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Chen L, Yang G, Bai Y, Chang J, Qin S, Liu F, He M, Song Y, Zhang F, Peñuelas J, Zhu B, Zhou G, Yang Y. Permafrost carbon cycle and its dynamics on the Tibetan Plateau. SCIENCE CHINA. LIFE SCIENCES 2024; 67:1833-1848. [PMID: 38951429 DOI: 10.1007/s11427-023-2601-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Accepted: 04/19/2024] [Indexed: 07/03/2024]
Abstract
Our knowledge on permafrost carbon (C) cycle is crucial for understanding its feedback to climate warming and developing nature-based solutions for mitigating climate change. To understand the characteristics of permafrost C cycle on the Tibetan Plateau, the largest alpine permafrost region around the world, we summarized recent advances including the stocks and fluxes of permafrost C and their responses to thawing, and depicted permafrost C dynamics within this century. We find that this alpine permafrost region stores approximately 14.1 Pg (1 Pg=1015 g) of soil organic C (SOC) in the top 3 m. Both substantial gaseous emissions and lateral C transport occur across this permafrost region. Moreover, the mobilization of frozen C is expedited by permafrost thaw, especially by the formation of thermokarst landscapes, which could release significant amounts of C into the atmosphere and surrounding water bodies. This alpine permafrost region nevertheless remains an important C sink, and its capacity to sequester C will continue to increase by 2100. For future perspectives, we would suggest developing long-term in situ observation networks of C stocks and fluxes with improved temporal and spatial coverage, and exploring the mechanisms underlying the response of ecosystem C cycle to permafrost thaw. In addition, it is essential to improve the projection of permafrost C dynamics through in-depth model-data fusion on the Tibetan Plateau.
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Affiliation(s)
- Leiyi Chen
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- China National Botanical Garden, Beijing, 100093, China
| | - Guibiao Yang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- China National Botanical Garden, Beijing, 100093, China
| | - Yuxuan Bai
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- China National Botanical Garden, Beijing, 100093, China
| | - Jinfeng Chang
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Shuqi Qin
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- China National Botanical Garden, Beijing, 100093, China
| | - Futing Liu
- Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration, Ecology and Nature Conservation Institute, Chinese Academy of Forestry, Beijing, 100091, China
| | - Mei He
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- China National Botanical Garden, Beijing, 100093, China
| | - Yutong Song
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- China National Botanical Garden, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Fan Zhang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- China National Botanical Garden, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Josep Peñuelas
- Consejo Superior de Investigaciones Científicas (CSIC), Global Ecology Unit CREAF-CSIC- UAB (Universitat Autònoma de Barcelona), Barcelona, 08193, Spain
- Centre for Ecological Research and Forestry (CREAF), Barcelona, 08193, Spain
| | - Biao Zhu
- Institute of Ecology, College of Urban and Environmental Sciences, and Key Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing, 100871, China
| | - Guoying Zhou
- Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, 810008, China
- Key Laboratory of Tibetan Medicine Research, Chinese Academy of Sciences, Xining, 810008, China
| | - Yuanhe Yang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China.
- China National Botanical Garden, Beijing, 100093, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
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Zhang LX, Zhou B, Song B, Zhao C, Adams JM, Xu Z. Significant carbon isotopic fractionation during early formation of biological soil crusts with indications for dryland carbon cycling. iScience 2024; 27:109114. [PMID: 38375221 PMCID: PMC10875157 DOI: 10.1016/j.isci.2024.109114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 01/05/2024] [Accepted: 01/31/2024] [Indexed: 02/21/2024] Open
Abstract
Clarifying the accumulation and decomposition of soil organic carbon (SOC) is crucial for comprehending carbon cycling in terrestrial ecosystems. SOC enrichment and decomposition lead to the fractionation of stable carbon isotopes, a complex process influenced by various factors, including microbes. However, this fractionation process during early soil formation and the role of microorganisms remain poorly explored. This study investigated the relative composition of stable carbon isotopes (δ13C) of recently formed biological soil crusts (BSCs) on stabilized sand dunes in the Tengger Desert, Northern China. A notable increase in δ13C was observed during early BSC development, likely driven by cyanobacteria's direct fixation of CO2. Yet, δ13C values of BSCs gradually declined, approaching those of soils under native vegetation, probably linked to microbial succession within the BSCs. This finding highlights the potential microbial influence on early soil carbon turnover and underscores the effectiveness of isotope tracers for studying this process.
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Affiliation(s)
- Li-Xuan Zhang
- School of Geography and Ocean Science, Nanjing University, 163 Xianlin Boulevard, Nanjing 210023, China
| | - Bin Zhou
- School of Earth Sciences and Engineering, Nanjing University, 163 Xianlin Boulevard, Nanjing 210023, China
| | - Bin Song
- School of Geography and Ocean Science, Nanjing University, 163 Xianlin Boulevard, Nanjing 210023, China
| | - Cheng Zhao
- School of Geography and Ocean Science, Nanjing University, 163 Xianlin Boulevard, Nanjing 210023, China
| | - Jonathan M. Adams
- School of Geography and Ocean Science, Nanjing University, 163 Xianlin Boulevard, Nanjing 210023, China
| | - Zhiwei Xu
- School of Geography and Ocean Science, Nanjing University, 163 Xianlin Boulevard, Nanjing 210023, China
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Amill F, Gauthier J, Rautio M, Derome N. Characterization of gill bacterial microbiota in wild Arctic char ( Salvelinus alpinus) across lakes, rivers, and bays in the Canadian Arctic ecosystems. Microbiol Spectr 2024; 12:e0294323. [PMID: 38329329 PMCID: PMC10923216 DOI: 10.1128/spectrum.02943-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 01/05/2024] [Indexed: 02/09/2024] Open
Abstract
Teleost gill mucus has a highly diverse microbiota, which plays an essential role in the host's fitness and is greatly influenced by the environment. Arctic char (Salvelinus alpinus), a salmonid well adapted to northern conditions, faces multiple stressors in the Arctic, including water chemistry modifications, that could negatively impact the gill microbiota dynamics related to the host's health. In the context of increasing environmental disturbances, we aimed to characterize the taxonomic distribution of transcriptionally active taxa within the bacterial gill microbiota of Arctic char in the Canadian Arctic in order to identify active bacterial composition that correlates with environmental factors. For this purpose, a total of 140 adult anadromous individuals were collected from rivers, lakes, and bays belonging to five Inuit communities located in four distinct hydrologic basins in the Canadian Arctic (Nunavut and Nunavik) during spring (May) and autumn (August). Various environmental factors were collected, including latitudes, water and air temperatures, oxygen concentration, pH, dissolved organic carbon (DOC), salinity, and chlorophyll-a concentration. The taxonomic distribution of transcriptionally active taxa within the gill microbiota was quantified by 16S rRNA gene transcripts sequencing. The results showed differential bacterial activity between the different geographical locations, explained by latitude, salinity, and, to a lesser extent, air temperature. Network analysis allowed the detection of a potential dysbiosis signature (i.e., bacterial imbalance) in fish gill microbiota from Duquet Lake in the Hudson Strait and the system Five Mile Inlet connected to the Hudson Bay, both showing the lowest alpha diversity and connectivity between taxa.IMPORTANCEThis paper aims to decipher the complex relationship between Arctic char (Salvelinus alpinus) and its symbiotic microbial consortium in gills. This salmonid is widespread in the Canadian Arctic and is the main protein and polyunsaturated fatty acids source for Inuit people. The influence of environmental parameters on gill microbiota in wild populations remains poorly understood. However, assessing the Arctic char's active gill bacterial community is essential to look for potential pathogens or dysbiosis that could threaten wild populations. Here, we concluded that Arctic char gill microbiota was mainly influenced by latitude and air temperature, the latter being correlated with water temperature. In addition, a dysbiosis signature detected in gill microbiota was potentially associated with poor fish health status recorded in these disturbed environments. With those results, we hypothesized that rapid climate change and increasing anthropic activities in the Arctic might profoundly disturb Arctic char gill microbiota, affecting their survival.
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Affiliation(s)
- Flora Amill
- Institute of Integrative and Systems Biology, Laval University, Quebec, Canada
| | - Jeff Gauthier
- Institute of Integrative and Systems Biology, Laval University, Quebec, Canada
| | - Milla Rautio
- Département des sciences fondamentales, Université du Québec à Chicoutimi, Chicoutimi, Quebec, Canada
| | - Nicolas Derome
- Institute of Integrative and Systems Biology, Laval University, Quebec, Canada
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Zhou P, Tian L, Siddique MS, Song S, Graham NJD, Zhu YG, Yu W. Divergent Fate and Roles of Dissolved Organic Matter from Spatially Varied Grassland Soils in China During Long-Term Biogeochemical Processes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:1164-1176. [PMID: 38164759 DOI: 10.1021/acs.est.3c08046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
Terrestrial dissolved organic matter (DOM) is critical to global carbon and nutrient cycling, climate change, and human health. However, how the spatial and compositional differences of soil DOM affect its dynamics and fate in water during the carbon cycle is largely unclear. Herein, the biodegradation of DOM from 14 spatially distributed grassland soils in China with diverse organic composition was investigated by 165 days of incubation experiments. The results showed that although the high humified fraction (high-HS) regions were featured by high humic-like fractions of 4-25 kDa molecular weight, especially the abundant condensed aromatics and tannins, they unexpectedly displayed greater DOM degradation during 45-165 days. In contrast, the unique proteinaceous and 25-100 kDa fractions enriched in the low humified fraction (low-HS) regions were drastically depleted and improved the decay of bulk DOM but only during 0-45 days. Together, DOM from the high-HS regions would cause lower CO2 outgassing to the atmosphere but higher organic loads for drinking water production in the short term than that from the low-HS regions. However, this would be reversed for the two regions during the long-term transformation processes. These findings highlight the importance of spatial and temporal variability of DOM biogeochemistry to mitigate the negative impacts of grassland soil DOM on climate, waters, and humans.
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Affiliation(s)
- Peng Zhou
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Long Tian
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Muhammad Saboor Siddique
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shian Song
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Nigel J D Graham
- Department of Civil and Environmental Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, U.K
| | - Yong-Guan Zhu
- State Key Lab of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Wenzheng Yu
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
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5
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Jiang C, Zhang S, Wang J, Xia X. Nitrous Oxide (N 2O) Emissions Decrease Significantly under Stronger Light Irradiance in Riverine Water Columns with Suspended Particles. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:19749-19759. [PMID: 37945339 DOI: 10.1021/acs.est.3c05526] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
Nitrous oxide (N2O) emissions from riverine water columns with suspended particles are important for the global N2O budget. Although sunlight is known to influence the activity of nitrogen-cycling microorganisms, its specific influence on N2O emissions in river systems remains unknown. This study analyzed the influences of light irradiance on N2O emissions in simulated oxic water columns with 15N-labeling and biological molecular techniques. Our results showed that N2O emissions were inhibited by light in the ammonium system (only 15NH4+ was added) and significantly decreased with increasing light irradiance in the nitrate system (only 15NO3- was added), despite contrasting variations in N2 emissions between these two systems. Lower N2O emission rates in the nitrate system under higher light conditions resulted from higher promotion levels of N2O reduction than N2O production. Increased N2O reduction was correlated to higher organic carbon bioavailability caused by photodegradation and greater potential for complete denitrification. Lower N2O production and higher N2O reduction were responsible for the lower N2O emissions observed in the ammonium system under light conditions. Our findings highlight the importance of sunlight in regulating N2O dynamics in riverine water columns, which should be considered in developing large-scale models for N2O processing and emissions in rivers.
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Affiliation(s)
- Chenrun Jiang
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
- Department of Urban Engineering, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656, Japan
| | - Sibo Zhang
- Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, China
| | - Junfeng Wang
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
| | - Xinghui Xia
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
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Wei Z, Li N, Zhang X, Zheng L, Mo S, Korshin G, Li Q, Yan M. Characterizing photochemical production carboxyl content of dissolved organic matters using absorbance spectroscopy combined with FT-ICR MS. CHEMOSPHERE 2023; 344:140352. [PMID: 37806326 DOI: 10.1016/j.chemosphere.2023.140352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 08/27/2023] [Accepted: 10/02/2023] [Indexed: 10/10/2023]
Abstract
Irradiation can significantly impact the structure, reactivity and environmental behavior of dissolved organic matter (DOM). The extent of these processes remains to be ascertained in more detail but the heterogeneity and site-specificity of DOM, and the lack of methods to characterize DOM at its environmentally-relevant concentrations make it a challenge. In this study, the differences of DOM response to photodegradation in four typical origins (i.e., surface water, sediment and intracellular and extracellular algal DOM) were tracked on the molecular-level using Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR MS). Changes of the carboxyl and phenolic DOM moieties induced by irradiation were quantified by spectroscopic titrations, and the mechanism of functional groups affecting the changes of specific molecular composition was qualitatively proposed. The results demonstrated that intracellular algal organic matter (I-DOM) was most susceptible to photodegradation (ca. 63% DOM loss), then came extracellular algal organic matter (E-DOM) and surface water DOM (W-DOM) (ca. 15% DOM loss). Sediment DOM (S-DOM) was most resistant to irradiation, with a very small level of its mineralization. Lipids, lignin-like compounds and tannin-like compounds in I-DOM and E-DOM were relatively photo-labile. The photodegradation of lipids was related to the decarboxylation of carboxyl functional groups, while the photodegradation of tannin-like compounds was related to the rupture of phenolic functional groups. In comparison, the molecular composition of W-DOM and S-DOM was less affected by irradiation, which was also reflected in the fact that the carboxyl and phenolic functional groups were highly photo-resistant. This study showed that the photoactivity of DOM in surface water was closely related to the abundance of algae, so controlling the excessive reproduction of algae may have a positive effect on stability of quality and quantity of organic matter in surface water.
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Affiliation(s)
- Zizhuo Wei
- College of Resources and Civil Engineering, Northeastern University, Shenyang, 110819, Liaoning, China; Qinhuangdao key Laboratory of Water-saving Pollution Control and Ecological Restoration, College of Resources and Materials, Northeastern University at Qinhuangdao, Qinhuangdao, 066004, Hebei, China
| | - Na Li
- College of Resources and Civil Engineering, Northeastern University, Shenyang, 110819, Liaoning, China; Qinhuangdao key Laboratory of Water-saving Pollution Control and Ecological Restoration, College of Resources and Materials, Northeastern University at Qinhuangdao, Qinhuangdao, 066004, Hebei, China
| | - Xinyi Zhang
- College of Water Resources and Hydropower Engineering, North China Electric Power University, Beijing 102208, China
| | - Lei Zheng
- College of Water Resources and Hydropower Engineering, North China Electric Power University, Beijing 102208, China
| | - Shansheng Mo
- Department of Environmental Engineering, Peking University, The Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing 100871, China
| | - Gregory Korshin
- Department of Civil and Environmental Engineering, University of Washington, Box 352700, Seattle, WA 98195-2700, United States
| | - Qingwei Li
- College of Resources and Civil Engineering, Northeastern University, Shenyang, 110819, Liaoning, China; Qinhuangdao key Laboratory of Water-saving Pollution Control and Ecological Restoration, College of Resources and Materials, Northeastern University at Qinhuangdao, Qinhuangdao, 066004, Hebei, China
| | - Mingquan Yan
- Department of Environmental Engineering, Peking University, The Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing 100871, China.
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Milstead RP, Horvath ER, Remucal CK. Dissolved Organic Matter Composition Determines Its Susceptibility to Complete and Partial Photooxidation within Lakes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:11876-11885. [PMID: 37523443 DOI: 10.1021/acs.est.3c01500] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/02/2023]
Abstract
Dissolved organic matter (DOM) plays an important role in carbon cycling within inland surface waters. Under sunlight irradiation, DOM undergoes complete photooxidation to produce carbon dioxide (CO2) and partial photooxidation that alters the molecular composition of DOM. However, a mechanistic understanding of the relationship between DOM composition and its susceptibility to partial and complete photooxidation in surface waters is currently lacking. This work combines light exposure experiments with high-resolution mass spectrometry to investigate DOM photooxidation using two DOM isolates and DOM from 16 lakes that vary in trophic status and size. High ratios of oxygen consumption to dissolved inorganic carbon (DIC) production demonstrate that all samples undergo extensive partial photooxidation. At the molecular level, more oxidized, aromatic DOM formulas are associated with oxygen consumption and DIC production. Bulk level measurements indicate that DOM becomes less aromatic and lower in apparent molecular weight following partial photooxidation, and there is molecular level evidence of oxygen addition and loss of CO2 in all samples. However, formulas most susceptible to photooxidation vary depending on the initial DOM composition. Collectively, this work provides insights into the relationship between DOM composition and photooxidation, which has important implications for carbon cycling in diverse surface waters.
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Affiliation(s)
- Reid P Milstead
- Environmental Chemistry and Technology Program, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Emma R Horvath
- Department of Civil and Environmental Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Christina K Remucal
- Environmental Chemistry and Technology Program, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
- Department of Civil and Environmental Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
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Hu J, Kang L, Li Z, Feng X, Liang C, Wu Z, Zhou W, Liu X, Yang Y, Chen L. Photo-produced aromatic compounds stimulate microbial degradation of dissolved organic carbon in thermokarst lakes. Nat Commun 2023; 14:3681. [PMID: 37344478 DOI: 10.1038/s41467-023-39432-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 06/13/2023] [Indexed: 06/23/2023] Open
Abstract
Photochemical and biological degradation of dissolved organic carbon (DOC) and their interactions jointly contribute to the carbon dioxide released from surface waters in permafrost regions. However, the mechanisms that govern the coupled photochemical and biological degradation of DOC are still poorly understood in thermokarst lakes. Here, by combining Fourier transform ion cyclotron resonance mass spectrometry and microbial high-throughput sequencing, we conducted a sunlight and microbial degradation experiment using water samples collected from 10 thermokarst lakes along a 1100-km permafrost transect. We demonstrate that the enhancement of sunlight on DOC biodegradation is not associated with the low molecular weight aliphatics produced by sunlight, but driven by the photo-produced aromatics. This aromatic compound-driven acceleration of biodegradation may be attributed to the potential high abilities of the microbes to decompose complex compounds in thermokarst lakes. These findings highlight the importance of aromatics in regulating the sunlight effects on DOC biodegradation in permafrost-affected lakes.
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Affiliation(s)
- Jie Hu
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Luyao Kang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ziliang Li
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xuehui Feng
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Caifan Liang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zan Wu
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Wei Zhou
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xuning Liu
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yuanhe Yang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Leiyi Chen
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China.
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9
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Barnes PW, Robson TM, Zepp RG, Bornman JF, Jansen MAK, Ossola R, Wang QW, Robinson SA, Foereid B, Klekociuk AR, Martinez-Abaigar J, Hou WC, Mackenzie R, Paul ND. Interactive effects of changes in UV radiation and climate on terrestrial ecosystems, biogeochemical cycles, and feedbacks to the climate system. Photochem Photobiol Sci 2023; 22:1049-1091. [PMID: 36723799 PMCID: PMC9889965 DOI: 10.1007/s43630-023-00376-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 01/13/2023] [Indexed: 02/02/2023]
Abstract
Terrestrial organisms and ecosystems are being exposed to new and rapidly changing combinations of solar UV radiation and other environmental factors because of ongoing changes in stratospheric ozone and climate. In this Quadrennial Assessment, we examine the interactive effects of changes in stratospheric ozone, UV radiation and climate on terrestrial ecosystems and biogeochemical cycles in the context of the Montreal Protocol. We specifically assess effects on terrestrial organisms, agriculture and food supply, biodiversity, ecosystem services and feedbacks to the climate system. Emphasis is placed on the role of extreme climate events in altering the exposure to UV radiation of organisms and ecosystems and the potential effects on biodiversity. We also address the responses of plants to increased temporal variability in solar UV radiation, the interactive effects of UV radiation and other climate change factors (e.g. drought, temperature) on crops, and the role of UV radiation in driving the breakdown of organic matter from dead plant material (i.e. litter) and biocides (pesticides and herbicides). Our assessment indicates that UV radiation and climate interact in various ways to affect the structure and function of terrestrial ecosystems, and that by protecting the ozone layer, the Montreal Protocol continues to play a vital role in maintaining healthy, diverse ecosystems on land that sustain life on Earth. Furthermore, the Montreal Protocol and its Kigali Amendment are mitigating some of the negative environmental consequences of climate change by limiting the emissions of greenhouse gases and protecting the carbon sequestration potential of vegetation and the terrestrial carbon pool.
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Affiliation(s)
- P W Barnes
- Biological Sciences and Environment Program, Loyola University New Orleans, New Orleans, USA.
| | - T M Robson
- Organismal & Evolutionary Biology (OEB), Faculty of Biological and Environmental Sciences, Viikki Plant Sciences Centre (ViPS), University of Helsinki, Helsinki, Finland.
- National School of Forestry, University of Cumbria, Ambleside, UK.
| | - R G Zepp
- ORD/CEMM, US Environmental Protection Agency, Athens, GA, USA
| | - J F Bornman
- Food Futures Institute, Murdoch University, Perth, Australia
| | | | - R Ossola
- Atmospheric Chemistry Observations and Modeling Laboratory, National Center for Atmospheric Research, Boulder, USA
| | - Q-W Wang
- Institute of Applied Ecology, Chinese Academy of Sciences (CAS), Shenyang, China
| | - S A Robinson
- Global Challenges Program & School of Earth, Atmospheric and Life Sciences, Securing Antarctica's Environmental Future, University of Wollongong, Wollongong, Australia
| | - B Foereid
- Environment and Natural Resources, Norwegian Institute of Bioeconomy Research, Ås, Norway
| | - A R Klekociuk
- Antarctic Climate Program, Australian Antarctic Division, Kingston, Australia
| | - J Martinez-Abaigar
- Faculty of Science and Technology, University of La Rioja, Logroño (La Rioja), Spain
| | - W-C Hou
- Department of Environmental Engineering, National Cheng Kung University, Tainan City, Taiwan
| | - R Mackenzie
- Cape Horn International Center (CHIC), Puerto Williams, Chile
- Millennium Institute Biodiversity of Antarctic and Subantarctic Ecosystems (BASE), Santiago, Chile
| | - N D Paul
- Lancaster Environment Centre, Lancaster University, Lancaster, UK
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Zhou L, Zhou Y, Zhang Y, Wu Y, Jang KS, Spencer RGM, Brookes JD, Jeppesen E. Hydrological Controls on Dissolved Organic Matter Composition throughout the Aquatic Continuum of the Watershed of Selin Co, the Largest Lake on the Tibetan Plateau. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:4668-4678. [PMID: 36892554 DOI: 10.1021/acs.est.2c08257] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Alpine river and lake systems on the Tibetan Plateau are highly sensitive indicators and amplifiers of global climate change and important components of the carbon cycle. Dissolved organic matter (DOM) encompasses organic carbon in aquatic systems, yet knowledge about DOM variation throughout the river-lake aquatic continuum within alpine regions is limited. We used optical spectroscopy, ultrahigh-resolution mass spectrometry (Fourier transform ion cyclotron resonance mass spectrometry), and stable water isotopic measurements to evaluate linkages between DOM composition and hydrological connection. We investigated glacial influences on DOM composition throughout the watershed of Selin Co, including upstream glacier-fed rivers and downstream-linked lakes. We found that the dissolved organic carbon concentration increased, whereas specific ultraviolet absorbance (SUVA254) decreased along the river-lake continuum. Relative to rivers, the downstream lakes had low relative abundances of polyphenolic and condensed aromatic compounds and humic-like substances but increased relative abundances of aliphatics and protein-like compounds. SUVA254 decreased while protein-like components increased with enriched stable water isotope δ2H-H2O, indicating that DOM aromaticity declined while autochthonous production increased along the flow paths. Glacier meltwater contributed to elevated relative abundances of aliphatic and protein-like compounds in headwater streams, while increased relative abundances of aromatics and humic-like DOM were found in glacier-fed lakes than downstream lakes. We conclude that changes in hydrological conditions, including glacier melt driven by a warming climate, will significantly alter DOM composition and potentially their biogeochemical function in surface waters on the Tibetan Plateau.
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Affiliation(s)
- Lei Zhou
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
- Taihu Laboratory for Lake Ecosystem Research, State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China
| | - Yongqiang Zhou
- Taihu Laboratory for Lake Ecosystem Research, State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China
| | - Yunlin Zhang
- Taihu Laboratory for Lake Ecosystem Research, State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China
| | - Yonghong Wu
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Kyoung-Soon Jang
- Bio-Chemical Analysis Team, Korea Basic Science Institute, Cheongju 28119, South Korea
| | - Robert G M Spencer
- Department of Earth, Ocean and Atmospheric Science, Florida State University, Tallahassee, Florida 32306, United States
| | - Justin D Brookes
- Water Research Centre, School of Biological Science, The University of Adelaide, 5005 Adelaide, Australia
| | - Erik Jeppesen
- Department of Bioscience and Center for Water Technology (WATEC), Aarhus University, Vejlsøvej 25, DK-8600 Silkeborg, Denmark
- Sino-Danish Centre for Education and Research, Beijing 100190, China
- Limnology Laboratory, Department of Biological Sciences and Centre for Ecosystem Research and Implementation, Middle East Technical University, Ankara 06800, Turkey
- Institute of Marine Sciences, Middle East Technical University, Mersin 33731, Turkey
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11
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Xu X, Wu C, Xie D, Ma J. Sources, Migration, Transformation, and Environmental Effects of Organic Carbon in Eutrophic Lakes: A Critical Review. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2023; 20:860. [PMID: 36613182 PMCID: PMC9820045 DOI: 10.3390/ijerph20010860] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 12/29/2022] [Accepted: 12/29/2022] [Indexed: 06/17/2023]
Abstract
Organic carbon (OC) plays a leading role in the carbon cycle of lakes and is crucial to carbon balances at regional and even global scales. In eutrophic lakes, in addition to external river inputs, the decomposition of endogenous grass and algae is a major source of organic carbon. Outbreaks of algal blooms (algal eutrophication) and the rapid growth of aquatic grasses (grass eutrophication) can lead to the accumulation and decay of large amounts of algae and aquatic grass debris, which increases the intensity of the carbon cycle of lakes and greatly impacts aquatic environments and ecosystems. The structures, decomposition processes, and distribution characteristics of algae and higher aquatic plant debris in eutrophic lakes are different from mesotrophic and oligotrophic lakes. Studying their accumulation dynamics and driving mechanisms is key to further understanding lake carbon cycles and their many interdependent pathways. This paper focuses on the carbon sources, tracing technologies, migration and transformation processes, and environmental effects of OC in eutrophic lakes. Based on the existing knowledge, we further combed the literature to identify the most important knowledge gaps preventing an in-depth understanding of the processes and driving mechanisms of the organic carbon cycle in eutrophic lakes.
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Affiliation(s)
- Xiaoguang Xu
- School of Environment, Nanjing Normal University, Nanjing 210023, China
| | - Chao Wu
- School of Environment, Nanjing Normal University, Nanjing 210023, China
| | - Dongyu Xie
- School of Environment, Nanjing Normal University, Nanjing 210023, China
| | - Jie Ma
- Nanjing Institute of Environmental Sciences, Ministry of Ecology and Environment, Nanjing 210042, China
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12
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Begum MS, Park JH, Yang L, Shin KH, Hur J. Optical and molecular indices of dissolved organic matter for estimating biodegradability and resulting carbon dioxide production in inland waters: A review. WATER RESEARCH 2023; 228:119362. [PMID: 36427460 DOI: 10.1016/j.watres.2022.119362] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 10/20/2022] [Accepted: 11/12/2022] [Indexed: 06/16/2023]
Abstract
Biodegradable dissolved organic carbon (BDOC) constitutes the most labile fraction of dissolved organic matter (DOM), which also functions as a source of CO2 emissions from inland waters. However, no systematic review is available on DOM indicators of BDOC and CO2 production potential. Optical and molecular indices can be used to track small changes in DOM composition during biodegradation. In this review, we identified four different methods for measuring BDOC together with their strengths and limitations. In addition, we discuss the potential of using documented optical indices based on absorption and fluorescence spectroscopy and molecular indices based on Fourier transform ion cyclotron mass spectrometry as proxies for estimating BDOC and biodegradation-induced CO2 production based on previously reported relationships in the literature. Many absorbance- and fluorescence-based indices showed inconsistent relationships with BDOC depending on watershed characteristics, hydrology, and anthropogenic impacts. Nevertheless, several indices, including specific UV absorbance at 254 nm (SUVA254), humification index (HIX), and terrestrial humic-like fluorescent DOM (FDOM) components, tended to have negative relationships with BDOC in tropical and temperate watersheds under baseflow or drought periods. Protein-like FDOM exhibited the strongest correlation with BDOC in different systems, except during storms and flood events. Despite the limited number of studies, DOM molecular indices exhibited consistent relationships with BDOC, suggesting that the relative abundance of aliphatic formulas and the molecular lability index could act as reliable proxies. The DOM optical indices explain up to 96% and 78% variability in BDOC and CO2, respectively; nonetheless, there were limited studies on molecular indices, which explain up to 74% variability in BDOC. Based on literature survey, we recommend several sensitive indices such as SUVA254, HIX, and terrestrial humic- and protein-like FDOM, which could be useful indicators of BDOC and dissolved CO2 in inland water. Future research should incorporate a wider range of geographic regions with various land use, hydrology, and anthropogenic disturbances to develop system- or condition-specific DOM optical or molecular proxies for better prediction of BDOC and CO2 emissions.
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Affiliation(s)
- Most Shirina Begum
- Department of Environment and Energy, Sejong University, Seoul 05006, South Korea
| | - Ji-Hyung Park
- Department of Environmental Science and Engineering, Ewha Womans University, Seoul 03760, South Korea
| | - Liyang Yang
- College of Environment and Safety Engineering, Fuzhou University, Fuzhou, Fujian, China
| | - Kyung Hoon Shin
- Department of Marine Science and Convergence Engineering, Hanyang University, Ansan, Gyeonggi do 15588, South Korea
| | - Jin Hur
- Department of Environment and Energy, Sejong University, Seoul 05006, South Korea.
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13
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Ren Z, Cao S, Chen T, Zhang C, Yu J. Bacterial functional redundancy and carbon metabolism potentials in soil, sediment, and water of thermokarst landscapes across the Qinghai-Tibet Plateau: Implications for the fate of permafrost carbon. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 852:158340. [PMID: 36041614 DOI: 10.1016/j.scitotenv.2022.158340] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2022] [Revised: 08/23/2022] [Accepted: 08/23/2022] [Indexed: 06/15/2023]
Abstract
Permafrost thaw create widespread thermokarst landscapes. As a result, distinct habitats are provided to harbor different bacterial communities in degraded permafrost soil (PBCs), thermokarst lake sediment (SBCs), and lake water (WBCs), driving carbon metabolism differentially. In this study, we investigated functional diversity and redundancy, and carbon metabolism potentials of PBCs, SBCs, and WBCs in thermokarst landscapes across the Qinghai-Tibet Plateau. The results showed that PBCs and SBCs had higher taxonomic and functional alpha diversity than WBCs, while WBCs had lower functional redundancy. WBCs had the highest beta diversity followed by SBCs and PBCs, suggesting strong determination of taxonomic variations on functional differences. Community assembly processes also had significant influences on beta diversity, especially for SBCs. Metabolism pathways of carbohydrate metabolism, methane metabolism, and carbon fixation were enriched differentially in PBCs, SBCs, and WBCs, suggesting different C fate in distinct habitats. Carbohydrate metabolism data suggested that PBCs might have stronger potentials to mineralize a greater diversity of organic carbon substrate than SBCs and WBCs, promoting degradation of organic carbon stocks in degraded permafrost soils. Methane metabolism data showed that SBCs had a stronger methanogenesis potential followed by PBCs and WBCs, while PBCs had a stronger methane oxidation potential. High abundance of genes involving in formaldehyde assimilation might suggested that a large proportion of produced methane might be assimilated by methanotrophs in the thermokarst landscapes. Both aerobic and anaerobic carbon fixation pathways were enriched in PBCs. The results added our understanding of functional properties and biogeochemical carbon cycles in thermokarst landscapes, improving our abilities in accurate modeling of carbon dynamics and the ultimate fate of permafrost carbon in a warming world.
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Affiliation(s)
- Ze Ren
- Research and Development Center for Watershed Environmental Eco-Engineering, Advanced Institute of Natural Sciences, Beijing Normal University, Zhuhai 519087, China; School of Environment, Beijing Normal University, Beijing 100875, China.
| | - Shengkui Cao
- School of Geographical Science, Qinghai Normal University, Xining 810008, China.
| | - Tao Chen
- Center for Grassland Microbiome, State Key Laboratory of Grassland Agro-ecosystems, Lanzhou University, Lanzhou 730020, China
| | - Cheng Zhang
- Research and Development Center for Watershed Environmental Eco-Engineering, Advanced Institute of Natural Sciences, Beijing Normal University, Zhuhai 519087, China; School of Engineering Technology, Beijing Normal University, Zhuhai 519087, China
| | - Jinlei Yu
- Key Laboratory of Geographic Information Science, Ministry of Education, East China Normal University, Shanghai 200241, China
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14
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Berggren M, Guillemette F, Bieroza M, Buffam I, Deininger A, Hawkes JA, Kothawala DN, LaBrie R, Lapierre JF, Murphy KR, Al-Kharusi ES, Rulli MPD, Hensgens G, Younes H, Wünsch UJ. Unified understanding of intrinsic and extrinsic controls of dissolved organic carbon reactivity in aquatic ecosystems. Ecology 2022; 103:e3763. [PMID: 35612376 PMCID: PMC9540823 DOI: 10.1002/ecy.3763] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 04/18/2022] [Indexed: 11/15/2022]
Abstract
Despite our growing understanding of the global carbon cycle, scientific consensus on the drivers and mechanisms that control dissolved organic carbon (DOC) turnover in aquatic systems is lacking, hampered by the mismatch between research that approaches DOC reactivity from either intrinsic (inherent chemical properties) or extrinsic (environmental context) perspectives. Here we propose a conceptual view of DOC reactivity in which the combination of intrinsic and extrinsic factors controls turnover rates and determines which reactions will occur. We review three major types of reactions (biological, photochemical, and flocculation) from an intrinsic chemical perspective and further define the environmental features that modulate the expression of chemically inherent reactivity potential. Finally, we propose hypotheses of how extrinsic and intrinsic factors together shape patterns in DOC turnover across the land‐to‐ocean continuum, underscoring that there is no intrinsic DOC reactivity without environmental context. By acknowledging the intrinsic–extrinsic control duality, our framework intends to foster improved modeling of DOC reactivity and its impact on ecosystem services.
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Affiliation(s)
- Martin Berggren
- Department of Physical Geography and Ecosystem Science, Lund University, Lund, Sweden
| | - François Guillemette
- Département des sciences de l'environnement, Université du Québec à Trois-Rivières, Canada.,Groupe de recherche interuniversitaire en limnologie (GRIL), Montréal, Canada
| | - Magdalena Bieroza
- Department of Soil and Environment, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Ishi Buffam
- Department of Landscape Architecture, Planning and Management, Swedish University of Agricultural Sciences, Alnarp, Sweden
| | - Anne Deininger
- Norwegian Institute for Water Research (NIVA), Oslo, Norway.,Centre for Coastal Research (CCR), University of Agder, Kristiansand, Norway
| | - Jeffrey A Hawkes
- Department of Chemistry, BMC, Uppsala University, Uppsala, Sweden
| | - Dolly N Kothawala
- Department of Ecology and Genetics, Uppsala University, Uppsala, Sweden
| | - Richard LaBrie
- Groupe de recherche interuniversitaire en limnologie (GRIL), Montréal, Canada.,Département des Sciences biologiques, Université de Montréal, Montréal, Canada
| | - Jean-François Lapierre
- Groupe de recherche interuniversitaire en limnologie (GRIL), Montréal, Canada.,Département des Sciences biologiques, Université de Montréal, Montréal, Canada
| | - Kathleen R Murphy
- Department of Architecture and Civil Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Enass S Al-Kharusi
- Department of Physical Geography and Ecosystem Science, Lund University, Lund, Sweden
| | - Mayra P D Rulli
- Department of Physical Geography and Ecosystem Science, Lund University, Lund, Sweden
| | - Geert Hensgens
- Department of Physical Geography and Ecosystem Science, Lund University, Lund, Sweden
| | - Hani Younes
- Department of Physical Geography and Ecosystem Science, Lund University, Lund, Sweden
| | - Urban J Wünsch
- Department of Architecture and Civil Engineering, Chalmers University of Technology, Gothenburg, Sweden
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15
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Liu F, Wang D. Dissolved organic carbon concentration and biodegradability across the global rivers: A meta-analysis. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 818:151828. [PMID: 34813803 DOI: 10.1016/j.scitotenv.2021.151828] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 11/12/2021] [Accepted: 11/16/2021] [Indexed: 06/13/2023]
Abstract
Riverine dissolved organic carbon (DOC) exerts a vital role in the global carbon cycle. Although substantial studies have explored DOC dynamics in aquatic ecosystems, it remains unknown about the patterns and drivers of riverine DOC concentration and biodegradability at the global scale. Here, by synthesizing 396 data points from 42 published literatures worldwide, we explored the spatial variations and controls of riverine DOC concentration and biodegradability. Our results revealed that the DOC concentration varied largely across the global rivers, with an average concentration of 10.4 mg L-1. The variations of DOC concentration were influenced by mean annual precipitation, vegetation type, soil type, permafrost degradation and river order. Furthermore, our results illustrated that the riverine DOC also had high biodegradability, showing an average of 16.4% loss within less than 90 days. The biodegradability of DOC was dominantly regulated by inorganic nutrients and DOC composition, but the controlling factors exhibited significant differences between small streams and large rivers. For small streams, DOC composition was the primary driver influencing DOC biodegradability, while for large rivers, nitrogen availability became the dominant factor affecting DOC biodegradability. This study highlights the high concentration and biodegradability of riverine DOC, which could exert an important role in the feedbacks between the global carbon cycle and climate warming.
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Affiliation(s)
- Futing Liu
- Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration, Institute of Forest Ecology, Environment and Nature Conservation, Chinese Academy of Forestry, Beijing 100091, China; Key Laboratory of Tree Breeding and Cultivation of the State Forestry and Grassland Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing 100091, China
| | - Dong Wang
- Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration, Institute of Forest Ecology, Environment and Nature Conservation, Chinese Academy of Forestry, Beijing 100091, China; Key Laboratory of Tree Breeding and Cultivation of the State Forestry and Grassland Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing 100091, China.
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16
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Cooper WT, Chanton JC, D'Andrilli J, Hodgkins SB, Podgorski DC, Stenson AC, Tfaily MM, Wilson RM. A History of Molecular Level Analysis of Natural Organic Matter by FTICR Mass Spectrometry and The Paradigm Shift in Organic Geochemistry. MASS SPECTROMETRY REVIEWS 2022; 41:215-239. [PMID: 33368436 DOI: 10.1002/mas.21663] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 09/16/2020] [Accepted: 09/16/2020] [Indexed: 06/12/2023]
Abstract
Natural organic matter (NOM) is a complex mixture of biogenic molecules resulting from the deposition and transformation of plant and animal matter. It has long been recognized that NOM plays an important role in many geological, geochemical, and environmental processes. Of particular concern is the fate of NOM in response to a warming climate in environments that have historically sequestered carbon (e.g., peatlands and swamps) but may transition to net carbon emitters. In this review, we will highlight developments in the application of high-field Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) in identifying the individual components of complex NOM mixtures, focusing primarily on the fraction that is dissolved in natural waters (dissolved organic matter or DOM). We will first provide some historical perspective on developments in FTICR technology that made molecular-level characterizations of DOM possible. A variety of applications of the technique will then be described, followed by our view of the future of high-field FTICR MS in carbon cycling research, including a particularly exciting metabolomic approach.
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Affiliation(s)
- William T Cooper
- Department of Chemistry & Biochemistry, Florida State University, Tallahassee, FL
| | - Jeffrey C Chanton
- Department of Earth, Ocean and Atmospheric Science, Florida State University, Tallahassee, FL
| | | | | | | | | | - Malak M Tfaily
- Department of Environmental Science, University of Arizona, Tucson, AZ
| | - Rachel M Wilson
- Department of Earth, Ocean and Atmospheric Science, Florida State University, Tallahassee, FL
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17
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Harms TK, Groffman PM, Aluwihare L, Craft C, Wieder WR, Hobbie SE, Baer SG, Blair JM, Frey S, Remucal CK, Rudgers JA, Collins SL, Kominoski JS, Ball BA. Patterns and trends of organic matter processing and transport: Insights from the US long-term ecological research network. CLIMATE CHANGE ECOLOGY 2021. [DOI: 10.1016/j.ecochg.2021.100025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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18
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Crandall T, Jones E, Greenhalgh M, Frei RJ, Griffin N, Severe E, Maxwell J, Patch L, St. Clair SI, Bratsman S, Merritt M, Norris AJ, Carling GT, Hansen N, St. Clair SB, Abbott BW. Megafire affects stream sediment flux and dissolved organic matter reactivity, but land use dominates nutrient dynamics in semiarid watersheds. PLoS One 2021; 16:e0257733. [PMID: 34555099 PMCID: PMC8460006 DOI: 10.1371/journal.pone.0257733] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 09/08/2021] [Indexed: 01/05/2023] Open
Abstract
Climate change is causing larger wildfires and more extreme precipitation events in many regions. As these ecological disturbances increasingly coincide, they alter lateral fluxes of sediment, organic matter, and nutrients. Here, we report the stream chemistry response of watersheds in a semiarid region of Utah (USA) that were affected by a megafire followed by an extreme precipitation event in October 2018. We analyzed daily to hourly water samples at 10 stream locations from before the storm event until three weeks after its conclusion for suspended sediment, solute and nutrient concentrations, water isotopes, and dissolved organic matter concentration, optical properties, and reactivity. The megafire caused a ~2,000-fold increase in sediment flux and a ~6,000-fold increase in particulate carbon and nitrogen flux over the course of the storm. Unexpectedly, dissolved organic carbon (DOC) concentration was 2.1-fold higher in burned watersheds, despite the decreased organic matter from the fire. DOC from burned watersheds was 1.3-fold more biodegradable and 2.0-fold more photodegradable than in unburned watersheds based on 28-day dark and light incubations. Regardless of burn status, nutrient concentrations were higher in watersheds with greater urban and agricultural land use. Likewise, human land use had a greater effect than megafire on apparent hydrological residence time, with rapid stormwater signals in urban and agricultural areas but a gradual stormwater pulse in areas without direct human influence. These findings highlight how megafires and intense rainfall increase short-term particulate flux and alter organic matter concentration and characteristics. However, in contrast with previous research, which has largely focused on burned-unburned comparisons in pristine watersheds, we found that direct human influence exerted a primary control on nutrient status. Reducing anthropogenic nutrient sources could therefore increase socioecological resilience of surface water networks to changing wildfire regimes.
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Affiliation(s)
- Trevor Crandall
- Department of Plant and Wildlife Sciences, Brigham Young University, Provo, Utah, United States of America
- Cimarron Valley Research Station, Oklahoma State University, Perkins, Oklahoma, United States of America
| | - Erin Jones
- Department of Plant and Wildlife Sciences, Brigham Young University, Provo, Utah, United States of America
| | - Mitchell Greenhalgh
- Department of Plant and Wildlife Sciences, Brigham Young University, Provo, Utah, United States of America
| | - Rebecca J. Frei
- Department of Plant and Wildlife Sciences, Brigham Young University, Provo, Utah, United States of America
- Department of Renewable Resources, University of Alberta, Edmonton, Alberta, Canada
| | - Natasha Griffin
- Department of Plant and Wildlife Sciences, Brigham Young University, Provo, Utah, United States of America
| | - Emilee Severe
- Department of Plant and Wildlife Sciences, Brigham Young University, Provo, Utah, United States of America
| | - Jordan Maxwell
- Department of Plant and Wildlife Sciences, Brigham Young University, Provo, Utah, United States of America
| | - Leika Patch
- Department of Plant and Wildlife Sciences, Brigham Young University, Provo, Utah, United States of America
| | - S. Isaac St. Clair
- Department of Statistics, Brigham Young University, Provo, Utah, United States of America
| | - Sam Bratsman
- Department of Plant and Wildlife Sciences, Brigham Young University, Provo, Utah, United States of America
| | - Marina Merritt
- Department of Chemical Engineering, Brigham Young University, Provo, Utah, United States of America
| | - Adam J. Norris
- Department of Plant and Wildlife Sciences, Brigham Young University, Provo, Utah, United States of America
| | - Gregory T. Carling
- Department of Geological Sciences, Brigham Young University, Provo, Utah, United States of America
| | - Neil Hansen
- Department of Plant and Wildlife Sciences, Brigham Young University, Provo, Utah, United States of America
| | - Samuel B. St. Clair
- Department of Plant and Wildlife Sciences, Brigham Young University, Provo, Utah, United States of America
| | - Benjamin W. Abbott
- Department of Plant and Wildlife Sciences, Brigham Young University, Provo, Utah, United States of America
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19
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Chen M, Kim JH, Lee YK, Lee DH, Jin YK, Hur J. Subsea permafrost as a potential major source of dissolved organic matter to the East Siberian Arctic Shelf. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 777:146100. [PMID: 33684745 DOI: 10.1016/j.scitotenv.2021.146100] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Revised: 02/20/2021] [Accepted: 02/21/2021] [Indexed: 06/12/2023]
Abstract
Arctic subsea permafrost contains more organic carbon than the terrestrial counterpart (~1400 Pg C vs. ~1000 Pg C) and is undergoing fast degradation (at rates of ~10 to 30 cm yr-1 over the past 3 decades) in response to climate warming. Yet the flux of organic carbon sequestered in the sediments of subsea permafrost to overlying water column, which can trigger enormous positive carbon-climate feedbacks, remain unclear. In this study, we examined the dissolved organic matter (DOM) diffusion to bottom seawaters from East Siberian Sea (ESS) sediments, which was estimated at about 943-2240 g C m-2 yr-1 and 10-55 g C m-2 yr-1 at the continuous-discontinuous transition zone of subsea permafrost and the remainder shelf and slope sites, respectively. The released DOM is characterized by prevailing dominance (≥ 98%) of low molecular weight (Mn < 350 Da) fractions. A red-shifted (emission wavelength >500 nm) fluorescence fingerprint, a typical feature of sediment/soil DOM, accounts for 4-6% and 7-8% in the fluorescence distributions of seawaters and pore waters, respectively, on ESS shelf. Statistical analysis revealed that seawaters and pore waters possessed similar DOM composition. The estimated total benthic efflux of dissolved organic carbon (DOC) was ~0.7-1.0 Pg C yr-1 when the estimate was scaled up to the entire Arctic shelf underlain with subsea permafrost assuming the width of continuous-discontinuous transition zone is 1 to 10 m. This estimation is consistent with the established ~10-30 cm yr-1 degradation rates of subsea permafrost by estimating its thaw-out time. Compiled observation data suggested that subsea permafrost might be a major DOM source to the Arctic Ocean, which could release tremendous carbon upon remineralization via its degradation to CO2 and CH4 in the water column.
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Affiliation(s)
- Meilian Chen
- Environmental Program, Guangdong Technion - Israel Institute of Technology, Shantou 515063, China.
| | - Ji-Hoon Kim
- Petroleum and Marine Research Division, Korea Institute of Geoscience and Mineral Resources, 124 Gwahak-ro, Yuseong-gu, Daejeon 34132, South Korea
| | - Yun Kyung Lee
- Department of Environment & Energy, Sejong University, Seoul 05006, South Korea
| | - Dong-Hun Lee
- Hanyang University ERICA Campus, 15588 Ansan, South Korea; Marine Environment Research Division, National Institute of Fisheries Science, 216, Gijanghaean-ro, Gijang-eup, Busan 46083, South Korea
| | - Young Keun Jin
- Korea Polar Research Institute (KOPRI), Incheon 21990, South Korea
| | - Jin Hur
- Department of Environment & Energy, Sejong University, Seoul 05006, South Korea.
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20
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Wologo E, Shakil S, Zolkos S, Textor S, Ewing S, Klassen J, Spencer RGM, Podgorski DC, Tank SE, Baker MA, O'Donnell JA, Wickland KP, Foks SSW, Zarnetske JP, Lee‐Cullin J, Liu F, Yang Y, Kortelainen P, Kolehmainen J, Dean JF, Vonk JE, Holmes RM, Pinay G, Powell MM, Howe J, Frei RJ, Bratsman SP, Abbott BW. Stream Dissolved Organic Matter in Permafrost Regions Shows Surprising Compositional Similarities but Negative Priming and Nutrient Effects. GLOBAL BIOGEOCHEMICAL CYCLES 2021; 35:e2020GB006719. [PMID: 33519064 PMCID: PMC7816262 DOI: 10.1029/2020gb006719] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 09/05/2020] [Accepted: 09/22/2020] [Indexed: 05/04/2023]
Abstract
Permafrost degradation is delivering bioavailable dissolved organic matter (DOM) and inorganic nutrients to surface water networks. While these permafrost subsidies represent a small portion of total fluvial DOM and nutrient fluxes, they could influence food webs and net ecosystem carbon balance via priming or nutrient effects that destabilize background DOM. We investigated how addition of biolabile carbon (acetate) and inorganic nutrients (nitrogen and phosphorus) affected DOM decomposition with 28-day incubations. We incubated late-summer stream water from 23 locations nested in seven northern or high-altitude regions in Asia, Europe, and North America. DOM loss ranged from 3% to 52%, showing a variety of longitudinal patterns within stream networks. DOM optical properties varied widely, but DOM showed compositional similarity based on Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) analysis. Addition of acetate and nutrients decreased bulk DOM mineralization (i.e., negative priming), with more negative effects on biodegradable DOM but neutral or positive effects on stable DOM. Unexpectedly, acetate and nutrients triggered breakdown of colored DOM (CDOM), with median decreases of 1.6% in the control and 22% in the amended treatment. Additionally, the uptake of added acetate was strongly limited by nutrient availability across sites. These findings suggest that biolabile DOM and nutrients released from degrading permafrost may decrease background DOM mineralization but alter stoichiometry and light conditions in receiving waterbodies. We conclude that priming and nutrient effects are coupled in northern aquatic ecosystems and that quantifying two-way interactions between DOM properties and environmental conditions could resolve conflicting observations about the drivers of DOM in permafrost zone waterways.
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Affiliation(s)
- Ethan Wologo
- Department of Land Resources and Environmental SciencesMontana State UniversityBozemanMTUSA
| | - Sarah Shakil
- Department of Biological SciencesUniversity of AlbertaEdmontonAlbertaCanada
| | - Scott Zolkos
- Department of Biological SciencesUniversity of AlbertaEdmontonAlbertaCanada
- Woods Hole Research CenterWoods HoleMAUSA
| | - Sadie Textor
- Department of Earth, Ocean and Atmospheric Science and National High Magnetic Field Laboratory Geochemistry GroupFlorida State UniversityTallahasseeFLUSA
| | - Stephanie Ewing
- Department of Land Resources and Environmental SciencesMontana State UniversityBozemanMTUSA
| | - Jane Klassen
- Department of Land Resources and Environmental SciencesMontana State UniversityBozemanMTUSA
| | - Robert G. M. Spencer
- Department of Earth, Ocean and Atmospheric Science and National High Magnetic Field Laboratory Geochemistry GroupFlorida State UniversityTallahasseeFLUSA
| | - David C. Podgorski
- Department of Earth, Ocean and Atmospheric Science and National High Magnetic Field Laboratory Geochemistry GroupFlorida State UniversityTallahasseeFLUSA
| | - Suzanne E. Tank
- Department of Biological SciencesUniversity of AlbertaEdmontonAlbertaCanada
| | - Michelle A. Baker
- Department of Biology and Ecology CenterUtah State UniversityLoganUTUSA
| | | | | | | | - Jay P. Zarnetske
- Department of Earth and Environmental SciencesMichigan State UniversityEast LansingMIUSA
| | - Joseph Lee‐Cullin
- Department of Earth and Environmental SciencesMichigan State UniversityEast LansingMIUSA
| | - Futing Liu
- State Key Laboratory of Vegetation and Environmental Change, Institute of BotanyChinese Academy of SciencesBeijingChina
| | - Yuanhe Yang
- State Key Laboratory of Vegetation and Environmental Change, Institute of BotanyChinese Academy of SciencesBeijingChina
| | | | | | - Joshua F. Dean
- Department of Earth SciencesVrije Universiteit AmsterdamAmsterdamNetherlands
- School of Environmental SciencesUniversity of LiverpoolLiverpoolUK
| | - Jorien E. Vonk
- Department of Earth SciencesVrije Universiteit AmsterdamAmsterdamNetherlands
| | | | - Gilles Pinay
- Environnement‐Ville‐Société (UMR5600) ‐ Centre National de la Recherche Scientifique (CNRS)LyonFrance
| | - Michaela M. Powell
- Department of Land Resources and Environmental SciencesMontana State UniversityBozemanMTUSA
| | - Jansen Howe
- Department of Plant and Wildlife SciencesBrigham Young UniversityProvoUTUSA
| | - Rebecca J. Frei
- Department of Plant and Wildlife SciencesBrigham Young UniversityProvoUTUSA
- Department of Renewable ResourcesUniversity of AlbertaEdmontonAlbertaCanada
| | - Samuel P. Bratsman
- Department of Plant and Wildlife SciencesBrigham Young UniversityProvoUTUSA
| | - Benjamin W. Abbott
- Department of Plant and Wildlife SciencesBrigham Young UniversityProvoUTUSA
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21
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Schwab MS, Hilton RG, Raymond PA, Haghipour N, Amos E, Tank SE, Holmes RM, Tipper ET, Eglinton TI. An Abrupt Aging of Dissolved Organic Carbon in Large Arctic Rivers. GEOPHYSICAL RESEARCH LETTERS 2020; 47:e2020GL088823. [PMID: 33380763 PMCID: PMC7757186 DOI: 10.1029/2020gl088823] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 10/06/2020] [Accepted: 10/14/2020] [Indexed: 06/12/2023]
Abstract
Permafrost thaw in Arctic watersheds threatens to mobilize hitherto sequestered carbon. We examine the radiocarbon activity (F14C) of dissolved organic carbon (DOC) in the northern Mackenzie River basin. From 2003-2017, DOC-F14C signatures (1.00 ± 0.04; n = 39) tracked atmospheric 14CO2, indicating export of "modern" carbon. This trend was interrupted in June 2018 by the widespread release of aged DOC (0.85 ± 0.16, n = 28) measured across three separate catchment areas. Increased nitrate concentrations in June 2018 lead us to attribute this pulse of 14C-depleted DOC to mobilization of previously frozen soil organic matter. We propose export through lateral perennial thaw zones that occurred at the base of the active layer weakened by preceding warm summer and winter seasons. Although we are not yet able to ascertain the broader significance of this "anomalous" mobilization event, it highlights the potential for rapid and large-scale release of aged carbon from permafrost.
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Affiliation(s)
| | | | - Peter A. Raymond
- Yale School of Forestry and Environmental StudiesYale UniversityNew HavenCTUSA
| | - Negar Haghipour
- Department of Earth SciencesETH ZurichZurichSwitzerland
- Laboratory of Ion Beam PhysicsETH ZurichZurichSwitzerland
| | - Edwin Amos
- Aurora Research InstituteInuvikNorthwest TerritoriesCanada
| | - Suzanne E. Tank
- Department of Biological SciencesUniversity of AlbertaEdmontonAlbertaCanada
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22
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Nalven SG, Ward CP, Payet JP, Cory RM, Kling GW, Sharpton TJ, Sullivan CM, Crump BC. Experimental metatranscriptomics reveals the costs and benefits of dissolved organic matter photo‐alteration for freshwater microbes. Environ Microbiol 2020; 22:3505-3521. [DOI: 10.1111/1462-2920.15121] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 06/03/2020] [Indexed: 12/25/2022]
Affiliation(s)
- Sarah G. Nalven
- Oregon State University Corvallis OR USA
- College of Earth, Ocean, and Atmospheric Sciences Oregon State University Corvallis OR USA
| | | | - Jérôme P. Payet
- Oregon State University Corvallis OR USA
- College of Earth, Ocean, and Atmospheric Sciences Oregon State University Corvallis OR USA
| | - Rose M. Cory
- College of Literature, Science, and the Arts Earth and Environmental Sciences University of Michigan Ann Arbor MI USA
- University of Michigan Ann Arbor MI USA
| | - George W. Kling
- University of Michigan Ann Arbor MI USA
- College of Literature, Science, and the Arts Ecology and Evolutionary Biology University of Michigan Ann Arbor MI USA
| | - Thomas J. Sharpton
- Oregon State University Corvallis OR USA
- Department of Microbiology Oregon State University Corvallis OR USA
| | - Christopher M. Sullivan
- Oregon State University Corvallis OR USA
- Center for Genome Research and Biocomputing Oregon State University Corvallis OR USA
| | - Byron C. Crump
- Oregon State University Corvallis OR USA
- College of Earth, Ocean, and Atmospheric Sciences Oregon State University Corvallis OR USA
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23
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Gagné KR, Ewers SC, Murphy CJ, Daanen R, Walter Anthony K, Guerard JJ. Composition and photo-reactivity of organic matter from permafrost soils and surface waters in interior Alaska. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2020; 22:1525-1539. [PMID: 32567618 DOI: 10.1039/d0em00097c] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Yedoma permafrost soils are especially susceptible to abrupt thaw due to their exceptional thickness and high ice content. Compared to other mineral soils, yedoma has a high organic carbon content, which has shown to be particularly biolabile. The organic carbon in these deposits needs to be characterised to provide an identification toolkit for detecting and monitoring the thaw, mobilisation and mineralisation of yedoma permafrost. This study characterised organic carbon isolates from thermokarst lakes (either receiving inputs from thaw of original yedoma or refrozen-thermokarst deposits, or lacking recent thaw) during winter and summer seasons within the Goldstream Creek watershed, a discontinuous permafrost watershed in interior Alaska, to identify the extent to which thermokarst-lake environments are impacted by degradation of yedoma permafrost. Waters from lakes of varied age and thermokarst activity, as well as active layer and undisturbed yedoma permafrost soils were isolated and characterised by functional group abundance (multiCP-MAS 13C and SPR-W5-WATERGATE 1H NMR), absorbance and fluorescence, and photobleaching ability. DOM isolated from winter and summer seasons revealed differing composition and photoreactivity, suggesting varied active layer and permafrost influence under differing ground water flow regimes. Water extractable organic matter isolates from permafrost leachates revealed variation in terms of photoreactivity and photolability, with the youngest sampled permafrost isolate being the most photoreactive and photolabile. As temperatures increase, release of permafrost organic matter is inevitable. Obtaining a holistic understanding of DOM composition and photoreactivity will allow for a better prediction of permafrost thaw impacts in the coming decades.
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Affiliation(s)
- Kristin R Gagné
- Department of Chemistry & Biochemistry, University of Alaska Fairbanks, Fairbanks, Alaska 99775, USA.
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24
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Drozdova OY, Aleshina AR, Tikhonov VV, Lapitskiy SA, Pokrovsky OS. Coagulation of organo-mineral colloids and formation of low molecular weight organic and metal complexes in boreal humic river water under UV-irradiation. CHEMOSPHERE 2020; 250:126216. [PMID: 32087384 DOI: 10.1016/j.chemosphere.2020.126216] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 02/11/2020] [Accepted: 02/13/2020] [Indexed: 06/10/2023]
Abstract
Photodegradation of dissolved organic matter (DOM) is highly important in humic waters of peatland regions, yet the coupling between organic and organo-mineral colloids, trace metals and bioavailability of photodegraded products is poorly known. Here we studied photo-destruction of organo-mineral colloids induced by UV-irradiation of sterile-filtered mire water. We revealed two simultaneously occurring processes of transformation of DOM and trace elements speciation: (i) disintegration of high molecular weight organo-mineral colloids into lower molecular weight (<1 kDa) DOM and metal complexes and (ii) formation of particulate (>0.22 μm) aggregates of metals and organic matter. Over 26 days of UV-irradiation, up to 20% of dissolved organic carbon from peat waters was transformed into CO2. In addition to transformation of organic compounds, sizeable change in speciation and size fractionation of many trace metals such as Fe, Pb, Cd, Co, Zn, Cu, V, La, Ni and Cr occurred. Although short-term (1 day) UV-irradiation of mire water stimulated growth of cultivable Pseudomonas sp. bacterium, the long-term exposure (26 days) of organic substrate had a negative effect on bacterial development. Therefore, while sizeable transformation of the organic and metal colloidal load of peat water may occur over first 10 days of UV-irradiation, the enhanced bioavailability of UV-treated substrate is achieved after first day of exposure. The present study demonstrates the importance of even short-term UV-irradiation on colloidal transformation and potential bioavailability of humic waters from temperate mires and highlights the need for more detailed study of coupled metal-organic matter transformation induced by sunlight exposure of mire waters.
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Affiliation(s)
- O Yu Drozdova
- Geological Faculty, Moscow State University, Leninskie Gory 1, 119234, Moscow, Russia.
| | - A R Aleshina
- Geological Faculty, Moscow State University, Leninskie Gory 1, 119234, Moscow, Russia; Scientific Geoinformation Center of Russian Academy of Sciences, New Arbat 11/1, 119019, Moscow, Russia
| | - V V Tikhonov
- Faculty of Soil Science, Moscow State University, Leninskie Gory 1/12, 119234, Moscow, Russia
| | - S A Lapitskiy
- Geological Faculty, Moscow State University, Leninskie Gory 1, 119234, Moscow, Russia
| | - O S Pokrovsky
- Geoscience and Environment Toulouse, UMR 5563 CNRS, University of Toulouse, 14 Avenue Edouard Belin, 31400, Toulouse, France; Institute of Ecological Problems of the North, N. Laverov Federal Center for Integrated Arctic Research, Nab. Severnoi Dviny 23, 163000, Arkhangelsk, Russia; BIO-GEO-CLIM Laboratory, Tomsk State University, Lenina Pr. 35, 634050, Tomsk, Russia
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25
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Ward CP, Cory RM. Assessing the prevalence, products, and pathways of dissolved organic matter partial photo-oxidation in arctic surface waters. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2020; 22:1214-1223. [PMID: 32073091 DOI: 10.1039/c9em00504h] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
In sunlit waters, photodegradation of dissolved organic matter (DOM) yields completely oxidized carbon (i.e., CO2) as well as a suite of partially oxidized compounds formed from oxygen incorporation (i.e., partial photo-oxidation). Of these two groups of DOM photo-products, more studies focus on CO2 (a greenhouse gas) than on partially oxidized DOM, which is likely a diverse group of compounds with poorly constrained roles in aquatic carbon cycling or biogeochemistry. The objective of this study is to address knowledge gaps on the prevalence, products, and pathways of DOM partial photo-oxidation. Here we traced the photochemical incorporation of isotopically labelled 18O2 into DOM isolated from Alaskan Arctic surface waters using high-resolution mass spectrometry. Complete and partial photo-oxidation of DOM was also quantified as CO2 production and O2 consumption. The majority of 18O-containing partial oxidation photo-products were classified as carboxylic rich alicyclic molecules (CRAM) and overlapped in composition with previously reported photo-products known to result from the oxidation of DOM by singlet oxygen. These results support a previously proposed hypothesis that photo-oxidation by singlet oxygen may contribute to the formation of CRAM, a compound class of DOM ubiquitously observed in surface waters. The novel application of an isotopic tracer for oxygen incorporation with a mass balance approach to quantify complete and partial photo-oxidation of DOM revealed that less than one mol of O2 is required to produce one mol of CO2. A sensitivity analysis based on this new knowledge demonstrated that the magnitude of DOM partial photo-oxidation may be underestimated by up to four-fold. Consequently, partial photo-oxidation likely plays a more prominent role in shaping DOM composition in sunlit waters of the Arctic than previously understood. Therefore, partial photo-oxidation should be increasingly incorporated into the experimental framework of studies focused on DOM composition in surface waters.
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Affiliation(s)
- Collin P Ward
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, USA.
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26
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Du H, Sun T, Wang D, Ming M. Bacterial and archaeal compositions and influencing factors in soils under different submergence time in a mercury-sensitive reservoir. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 191:110155. [PMID: 31972452 DOI: 10.1016/j.ecoenv.2019.110155] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 12/27/2019] [Accepted: 12/30/2019] [Indexed: 06/10/2023]
Abstract
Soils in the water-level-fluctuating zone (WLFZ) of Three Gorges Reservoir (TGR) inundated by water for different periods of time are confirmed to have disparate characteristics to mercury (Hg), and thus it is of great significance to further investigate microbial compositions and influencing factors. The objective of this study was to compare bacterial and archaeal richness, α-diversities and compositions, as well as affecting variables, especially Hg concentrations, among soils under different submergence time-SI (inundated soil), SS (semi-inundated soil), SN(non-inundated soil) and SSe (sediment)-based on high throughput sequencing. Results showed that sediment had significantly higher bacterial and archaeal richness and α-diversities than the other soil types. Anaerolinea and Aeromonas, as well as Altiarchaeales, Nitrosoarchaeum, and Methanosarta were dominant in SSe, while sharply decreasing in the other soil types, with significant difference among groups. An unclassified genus in SCG critically predominating in SI, SS and SN, drastically reduced in SSe, with extremely significant difference among groups. Bathyarchaeota and Nitrososphaera, both dominating in SSe, decreased dramatically and almost vanished in SI and SN. All the variables except pH posed a significant positive effect on bacterial and archaeal compositions in SSe, while opposite effect in the other three soil types. MeHg and THg concentrations had relatively weaker effects on microbial compositions comparing to variables like NH4+, CEC, OM and SO42+.
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Affiliation(s)
- Hongxia Du
- College of Resources and Environment, Southwest University, Chongqing, 400715, China; Chongqing Key Laboratory of Bioresource for Bioenergy, Southwest University, Chongqing, 400715, China
| | - Tao Sun
- College of Resources and Environment, Southwest University, Chongqing, 400715, China
| | - Dingyong Wang
- College of Resources and Environment, Southwest University, Chongqing, 400715, China
| | - Ma Ming
- College of Resources and Environment, Southwest University, Chongqing, 400715, China; Chongqing Key Laboratory of Bioresource for Bioenergy, Southwest University, Chongqing, 400715, China.
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27
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Jiang T, Wang D, Meng B, Chi J, Laudon H, Liu J. The concentrations and characteristics of dissolved organic matter in high-latitude lakes determine its ambient reducing capacity. WATER RESEARCH 2020; 169:115217. [PMID: 31675608 DOI: 10.1016/j.watres.2019.115217] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 10/16/2019] [Accepted: 10/18/2019] [Indexed: 06/10/2023]
Abstract
The reducing capacity (RC) of natural organic matter plays an important role in the carbon cycle and biogeochemical fates of environmental contaminants in the aquatic system. However, the electron donation potentials of dissolved organic matter (DOM) from high-latitude lakes are still uncertain. In this study, we collected DOM samples from high-latitude lakes across the Arctic and boreal regions in Sweden and Norway to investigate the effects of the DOM concentration and characteristics on its ambient reducing capacity (ARC). Mercury (Hg(II)) abiotic reduction in darkness was used to determine the ARC. The results showed that the DOM in Arctic lakes is less terrestrial-dominant than in reference sites (i.e., forest lakes). Between the two categories of Arctic lakes, tundra lakes are more terrestrial-influenced compared to mountain lakes. Additionally, terrestrial-originated DOM is a main controlling factor for enhancing the ambient reducing capacity, whereas the DOM concentration, i.e., dissolved organic carbon (DOC), resulted in variations in the Hg/DOC ratios that also cause the variations of the observed ARC values. Thus, comparisons of the ARC values can be conducted while oxidant/DOC ratios are kept the same and reported through the method using heavy metals as a chemical probe. After correction for Hg/DOC ratio interference, the ambient reducing capacity of DOM followed the order: boreal forest lakes > Arctic tundra lakes > Arctic mountain lakes. This study highlights that the DOM concentration should also be considered when estimating the ARC as compared to the previous that mainly focusing on the properties of DOM such as its origins. As climate change is projected to be severe in high latitudes, this study demonstrates a significant connection between aquatic DOM geochemical reactivity and terrestrial inputs, which is crucial for a better prediction of the role of DOM in high-latitude lakes in the context of climate change.
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Affiliation(s)
- Tao Jiang
- State Cultivation Base of Eco-agriculture for Southwest Mountainous Land, Department of Environmental Sciences and Engineering, College of Resources and Environment, Southwest University, Chongqing, 400716, China; Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, SE-90183, Sweden.
| | - Dingyong Wang
- State Cultivation Base of Eco-agriculture for Southwest Mountainous Land, Department of Environmental Sciences and Engineering, College of Resources and Environment, Southwest University, Chongqing, 400716, China; Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, SE-90183, Sweden
| | - Bo Meng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550002, China
| | - Jinshu Chi
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, SE-90183, Sweden
| | - Hjalmar Laudon
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, SE-90183, Sweden
| | - Jiang Liu
- State Cultivation Base of Eco-agriculture for Southwest Mountainous Land, Department of Environmental Sciences and Engineering, College of Resources and Environment, Southwest University, Chongqing, 400716, China; Centre for Earth Observation Science, Department of Environment and Geography, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
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28
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Zhou L, Zhou Y, Yao X, Cai J, Liu X, Tang X, Zhang Y, Jang KS, Jeppesen E. Decreasing diversity of rare bacterial subcommunities relates to dissolved organic matter along permafrost thawing gradients. ENVIRONMENT INTERNATIONAL 2020; 134:105330. [PMID: 31759274 DOI: 10.1016/j.envint.2019.105330] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 11/10/2019] [Accepted: 11/12/2019] [Indexed: 05/28/2023]
Abstract
Dissolved organic matter (DOM) released from permafrost thaw greatly influences the biogeochemical cycles of, among others, downstream carbon, nitrogen and phosphorus cycles; yet, knowledge of the linkages between bacterial communities with permafrost DOM heterogeneity is limited. Here, we aim at unravelling the responses of bacterial diversities and metabolic profiles to DOM quantity and composition across permafrost thawing gradients by coupling an extensive field investigation with bio-incubation experiments. Richness, evenness and dissimilarities of the whole and rare communities decreased from thermokarst pits to headstreams and to downstream rivers. The assemblages of the abundant subcommunities were mainly determined by ecological drift-driven stochastic processes. Both the optical and the molecular composition of DOM were significantly related to the changes of the whole (rare) bacterial communities (Mantel's correlation > 0.5, p < 0.01). Diversity indices of the whole and rare communities decreased with decreasing relative abundance of tannins, condensed aromatics and more aromatic and oxidized lignins as well as with decreased dissolved organic carbon and intensities of all fluorescence components. Laboratory DOM bio-incubation experiments further confirmed microbial consumption of more aromatic and oxidized compounds as well as decreasing metabolic diversities in terms of microbial degradation and production along permafrost thawing gradients. Our findings suggest that changes in the sources of permafrost-derived DOM induced by global warming can have different influences on the diversity and metabolism of bacterial communities and thus on permafrost carbon climate feedbacks along permafrost thawing gradients.
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Affiliation(s)
- Lei Zhou
- Taihu Laboratory for Lake Ecosystem Research, State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yongqiang Zhou
- Taihu Laboratory for Lake Ecosystem Research, State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaolong Yao
- Taihu Laboratory for Lake Ecosystem Research, State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jian Cai
- Taihu Laboratory for Lake Ecosystem Research, State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xin Liu
- Shanghai Municipal Engineering Design Institute (Group) CO., LTD, Shanghai 200092, China
| | - Xiangming Tang
- Taihu Laboratory for Lake Ecosystem Research, State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yunlin Zhang
- Taihu Laboratory for Lake Ecosystem Research, State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Kyoung-Soon Jang
- Biomedical Omics Group, Korea Basic Science Institute, Cheongju 28119, South Korea
| | - Erik Jeppesen
- Department of Bioscience and Arctic Research Centre, Aarhus University, DK-8600 Silkeborg, Denmark; Sino-Danish Centre for Education and Research, Beijing 100190, China; Limnology Laboratory and EKOSAM, Department of Biological Sciences, Middle East Technical University, Ankara, Turkey
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29
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Niu XZ, Harir M, Schmitt-Kopplin P, Croué JP. Sunlight-induced phototransformation of transphilic and hydrophobic fractions of Suwannee River dissolved organic matter. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 694:133737. [PMID: 31401506 DOI: 10.1016/j.scitotenv.2019.133737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 08/01/2019] [Accepted: 08/01/2019] [Indexed: 06/10/2023]
Abstract
Sunlight-induced chemical changes of both transphilic (SWR-TPH) and hydrophobic (SWR-HPO) fractions of Suwannee River dissolved organic matter (DOM) were followed by ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS). Irradiated SWR-TPH exhibited increase of chemodiversity, loss of some aromatic compounds, and almost no change in terms of average values of m/z, O/C and double bond equivalents (DBE). Irradiated SWR-HPO showed decrease of chemodiversity, average values of m/z, O/C and DBE. Irradiation of SWR-HPO produced oxygenated (O/C > 0.7) and aliphatic new compounds and removed some aromatics and carboxyl-rich alicyclic molecules (CRAM). Comparatively, CHO-compounds of SWR-TPH were relatively stable with a minor class of aromatic compounds disappeared under sunlight irradiation. Photochemical processing of SWR-HPO generated highly oxygenated new compounds that were readily present in SWR-TPH, implying that sunlight changes the hydrophobicity of DOM and that SWR-HPO is a photochemical precursor for SWR-TPH. This study contributed to the developing knowledge on organic matter phototransformation, particularly the transformation pattern of SWR-TPH that was never described previously; it also demonstrated the role of sunlight in producing SWR-TPH compounds from SWR-HPO and consequently driving the transformation of organic matter.
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Affiliation(s)
- Xi-Zhi Niu
- Curtin Water Quality Research Centre, School of Molecular and Life Sciences, Curtin University, GPO Box U1987, Perth, Western Australia 6845, Australia.
| | - Mourad Harir
- Analytical BioGeoChemistry, German Research Centre for Environmental Health, Helmholtz Zentrum München, Ingolstädter landstrasse. 1, 85764 Neuherberg, Germany; Chair of Analytical Food Chemistry, Technische Universität München, Freising-Weihenstephan, Germany
| | - Philippe Schmitt-Kopplin
- Analytical BioGeoChemistry, German Research Centre for Environmental Health, Helmholtz Zentrum München, Ingolstädter landstrasse. 1, 85764 Neuherberg, Germany; Chair of Analytical Food Chemistry, Technische Universität München, Freising-Weihenstephan, Germany
| | - Jean-Philippe Croué
- Curtin Water Quality Research Centre, School of Molecular and Life Sciences, Curtin University, GPO Box U1987, Perth, Western Australia 6845, Australia; Institut de Chimie des Milieux et des Materiaux IC2MP UMR 7285 CNRS, Universite de Poitiers, France.
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30
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Pieristè M, Chauvat M, Kotilainen TK, Jones AG, Aubert M, Robson TM, Forey E. Solar UV-A radiation and blue light enhance tree leaf litter decomposition in a temperate forest. Oecologia 2019; 191:191-203. [PMID: 31363838 PMCID: PMC6732127 DOI: 10.1007/s00442-019-04478-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 07/23/2019] [Indexed: 11/30/2022]
Abstract
Sunlight can accelerate the decomposition process through an ensemble of direct and indirect processes known as photodegradation. Although photodegradation is widely studied in arid environments, there have been few studies in temperate regions. This experiment investigated how exposure to solar radiation, and specifically UV-B, UV-A, and blue light, affects leaf litter decomposition under a temperate forest canopy in France. For this purpose, we employed custom-made litterbags built using filters that attenuated different regions of the solar spectrum. Litter mass loss and carbon to nitrogen (C:N) ratio of three species: European ash (Fraxinus excelsior), European beech (Fagus sylvatica) and pedunculate oak (Quercus robur), differing in their leaf traits and decomposition rate, were analysed over a period of 7–10 months. Over the entire period, the effect of treatments attenuating blue light and solar UV radiation on leaf litter decomposition was similar to that of our dark treatment, where litter lost 20–30% less mass and had a lower C:N ratio than under the full-spectrum treatment. Moreover, decomposition was affected more by the filter treatment than mesh size, which controlled access by mesofauna. The effect of filter treatment differed among the three species and appeared to depend on litter quality (and especially C:N), producing the greatest effect in recalcitrant litter (F. sylvatica). Even under the reduced irradiance found in the understorey of a temperate forest, UV radiation and blue light remain important in accelerating surface litter decomposition.
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Affiliation(s)
- Marta Pieristè
- Organismal and Evolutionary Biology (OEB), Viikki Plant Science Centre (ViPS), University of Helsinki, P.O. Box 65, Viikinkaari1, 00014, Helsinki, Finland. .,Normandie Université, UNIROUEN, IRSTEA, ECODIV, FR Scale CNRS 3730, Rouen, France.
| | - Matthieu Chauvat
- Normandie Université, UNIROUEN, IRSTEA, ECODIV, FR Scale CNRS 3730, Rouen, France
| | - Titta K Kotilainen
- Organismal and Evolutionary Biology (OEB), Viikki Plant Science Centre (ViPS), University of Helsinki, P.O. Box 65, Viikinkaari1, 00014, Helsinki, Finland.,Natural Resources Institute Finland, Itäinen Pitkäkatu 4a, 20520, Turku, FI, Finland
| | - Alan G Jones
- Earthwatch Institute, Mayfield House, 256 Banbury Road, Oxford, OX2 7DE, UK.,Forest Systems, Scion. 49 Sala Street, Private Bag 3020, Rotorua, 3046, New Zealand
| | - Michaël Aubert
- Normandie Université, UNIROUEN, IRSTEA, ECODIV, FR Scale CNRS 3730, Rouen, France
| | - T Matthew Robson
- Organismal and Evolutionary Biology (OEB), Viikki Plant Science Centre (ViPS), University of Helsinki, P.O. Box 65, Viikinkaari1, 00014, Helsinki, Finland
| | - Estelle Forey
- Normandie Université, UNIROUEN, IRSTEA, ECODIV, FR Scale CNRS 3730, Rouen, France
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Li A, Aubeneau AF, King T, Cory RM, Neilson BT, Bolster D, Packman AI. Effects of vertical hydrodynamic mixing on photomineralization of dissolved organic carbon in arctic surface waters. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2019; 21:748-760. [PMID: 30907904 DOI: 10.1039/c8em00455b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Photomineralization, the transformation of dissolved organic carbon (DOC) to CO2 by sunlight, is an important source of CO2 in arctic surface waters. However, quantifying the role of photomineralization in inland waters is limited by the understanding of hydrologic controls on this process. To bridge this gap, this study evaluates mixing limitations, i.e., whether and by how much vertical mixing limits the depth-integrated photomineralization rate, in freshwater systems. We developed a conceptual model to qualitatively assess mixing limitations across the range of light attenuation and hydrologic conditions observed in freshwaters. For the common case of exponential light attenuation over depth, we developed a mathematical model to quantify mixing limitation, and used this model to assess a range of arctic freshwater systems. The results demonstrate that mixing limitations are important when there is significant light attenuation by suspended sediment (SS), which is the case in some arctic, boreal and temperate waters. Mixing limitation is pronounced when light attenuation over depth is strong and when the photomineralization rate at the water surface exceeds the vertical mixing rate. Arctic streams and rivers have strong vertical mixing relative to surface photomineralization, such that model results demonstrate no mixing limitation regardless of how much SS is present. Our analysis indicates that well-mixed assumptions used in prior work are valid in many, but not all, arctic surface waters. The effects of mixing limitations in reducing the photomineralization rate must be considered in arctic lakes with high SS concentrations.
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Affiliation(s)
- Angang Li
- Civil and Environmental Engineering, Northwestern University, Evanston, IL, USA
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32
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Sulzberger B, Austin AT, Cory RM, Zepp RG, Paul ND. Solar UV radiation in a changing world: roles of cryosphere-land-water-atmosphere interfaces in global biogeochemical cycles. Photochem Photobiol Sci 2019; 18:747-774. [PMID: 30810562 PMCID: PMC7418111 DOI: 10.1039/c8pp90063a] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 12/19/2018] [Indexed: 12/29/2022]
Abstract
Global change influences biogeochemical cycles within and between environmental compartments (i.e., the cryosphere, terrestrial and aquatic ecosystems, and the atmosphere). A major effect of global change on carbon cycling is altered exposure of natural organic matter (NOM) to solar radiation, particularly solar UV radiation. In terrestrial and aquatic ecosystems, NOM is degraded by UV and visible radiation, resulting in the emission of carbon dioxide (CO2) and carbon monoxide, as well as a range of products that can be more easily degraded by microbes (photofacilitation). On land, droughts and land-use change can reduce plant cover causing an increase in exposure of plant litter to solar radiation. The altered transport of soil organic matter from terrestrial to aquatic ecosystems also can enhance exposure of NOM to solar radiation. An increase in emission of CO2 from terrestrial and aquatic ecosystems due to the effects of global warming, such as droughts and thawing of permafrost soils, fuels a positive feedback on global warming. This is also the case for greenhouse gases other than CO2, including methane and nitrous oxide, that are emitted from terrestrial and aquatic ecosystems. These trace gases also have indirect or direct impacts on stratospheric ozone concentrations. The interactive effects of UV radiation and climate change greatly alter the fate of synthetic and biological contaminants. Contaminants are degraded or inactivated by direct and indirect photochemical reactions. The balance between direct and indirect photodegradation or photoinactivation of contaminants is likely to change with future changes in stratospheric ozone, and with changes in runoff of coloured dissolved organic matter due to climate and land-use changes.
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Affiliation(s)
- B Sulzberger
- Eawag: Swiss Federal Institute of Aquatic Science and Technology, Duebendorf, Switzerland.
| | - A T Austin
- Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura (IFEVA) and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Facultad de Agronomía, Universidad de Buenos Aires en las afiliations, Buenos Aires, Argentina
| | - R M Cory
- University of Michigan, Earth & Environmental Science, Ann Arbor, Michigan, USA
| | - R G Zepp
- United States Environmental Protection Agency, Athens, Georgia, USA
| | - N D Paul
- Lancaster Environment Centre, Lancaster University, LA1 4YQ, UK
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33
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Zhou Y, Xiao Q, Yao X, Zhang Y, Zhang M, Shi K, Lee X, Podgorski DC, Qin B, Spencer RGM, Jeppesen E. Accumulation of Terrestrial Dissolved Organic Matter Potentially Enhances Dissolved Methane Levels in Eutrophic Lake Taihu, China. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:10297-10306. [PMID: 30141916 DOI: 10.1021/acs.est.8b02163] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Inland waters play an important role for the storage of chromophoric dissolved organic matter (CDOM) and outgassing of methane (CH4). However, to date, linkages between the optical dynamics of CDOM and dissolved CH4 levels remain largely unknown. We used multi-year (2012-2014) seasonal data series collected from Lake Taihu and 51 connecting channels to investigate how CDOM optical dynamics may impact dissolved CH4 levels in the lake. High dissolved CH4 in the northwestern inflowing river mouths coincided with high underwater UV-vis light availability, dissolved organic carbon (DOC), chemical oxygen demand (COD), DOM aromaticity, terrestrial humic-rich fluorescence, in situ measured terrestrial CDOM, depleted dissolved oxygen (DO), stable isotopic δ2H, and δ18O compared with other lake regions. Our results further revealed positive relationships between dissolved CH4 and CDOM absorption at 350 nm, i.e. a(350), COD, DOC, terrestrial humic-rich fluorophores, and DOM aromaticity, and negative relationships between dissolved CH4 and DO, δ2H, and δ18O. The central lake samples showed a major contribution of terrestrial-sourced molecular formulas to the ultrahigh resolution mass spectrometry data, suggesting the presence of allochthonous DOM sources even here. We conclude that an elevated terrestrial CDOM input likely enhances dissolved CH4 levels in Lake Taihu.
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Affiliation(s)
- Yongqiang Zhou
- State Key Laboratory of Lake Science and Environment , Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences , Nanjing 210008 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
- Sino-Danish Centre for Education and Research , Beijing 100190 , China
| | - Qitao Xiao
- State Key Laboratory of Lake Science and Environment , Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences , Nanjing 210008 , China
| | - Xiaolong Yao
- State Key Laboratory of Lake Science and Environment , Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences , Nanjing 210008 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Yunlin Zhang
- State Key Laboratory of Lake Science and Environment , Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences , Nanjing 210008 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Mi Zhang
- Yale-NUIST Center on Atmospheric Environment, International Joint Laboratory on Climate and Environment Change (ILCEC) , Nanjing University of Information Science and Technology , Nanjing 210044 , China
| | - Kun Shi
- State Key Laboratory of Lake Science and Environment , Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences , Nanjing 210008 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Xuhui Lee
- Yale-NUIST Center on Atmospheric Environment, International Joint Laboratory on Climate and Environment Change (ILCEC) , Nanjing University of Information Science and Technology , Nanjing 210044 , China
| | - David C Podgorski
- Pontchartrain Institute for Environmental Sciences, Department of Chemistry , University of New Orleans , New Orleans 70148 , Louisiana United States
| | - Boqiang Qin
- State Key Laboratory of Lake Science and Environment , Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences , Nanjing 210008 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Robert G M Spencer
- Department of Earth, Ocean and Atmospheric Science , Florida State University , Tallahassee , Florida 32306 , United States
| | - Erik Jeppesen
- Sino-Danish Centre for Education and Research , Beijing 100190 , China
- Department of Bioscience and Arctic Research Centre , Aarhus University , Vejlsøvej 25 , DK-8600 Silkeborg , Denmark
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34
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Jubb AM, Eskelsen JR, Yin X, Zheng J, Philben MJ, Pierce EM, Graham DE, Wullschleger SD, Gu B. Characterization of iron oxide nanoparticle films at the air-water interface in Arctic tundra waters. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 633:1460-1468. [PMID: 29758898 DOI: 10.1016/j.scitotenv.2018.03.332] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 03/26/2018] [Accepted: 03/27/2018] [Indexed: 06/08/2023]
Abstract
Massive amounts of organic carbon have accumulated in Arctic permafrost and soils due to anoxic and low temperature conditions that limit aerobic microbial respiration. Alternative electron acceptors are thus required for microbes to degrade organic carbon in these soils. Iron or iron oxides have been recognized to play an important role in carbon cycle processes in Arctic soils, although the exact form and role as an electron acceptor or donor remain poorly understood. Here, Arctic biofilms collected during the summers of 2016 and 2017 from tundra surface waters on the Seward Peninsula of western Alaska were characterized with a suite of microscopic and spectroscopic methods. We hypothesized that these films contain redox-active minerals bound to biological polymers. The major components of the films were found to be iron oxide nanoparticle aggregates associated with extracellular polymeric substances. The observed mineral phases varied between films collected in different years with magnetite (Fe2+Fe23+O4) nanoparticles (<5nm) predominantly identified in the 2016 films, while for films collected in 2017 ferrihydrite-like amorphous iron oxyhydroxides were found. While the exact formation mechanism of these Artic iron oxide films remains to be explored, the presence of magnetite and other iron oxide/oxyhydroxide nanoparticles at the air-water interface may represent a previously unknown source of electron acceptors for continual anaerobic microbial respiration of organic carbon within poorly drained Arctic tundra.
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Affiliation(s)
- Aaron M Jubb
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA.
| | - Jeremy R Eskelsen
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Xiangping Yin
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Jianqiu Zheng
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Michael J Philben
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Eric M Pierce
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - David E Graham
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA; Climate Change Science Institute, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Stan D Wullschleger
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA; Climate Change Science Institute, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Baohua Gu
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA; Department of Biosystems Engineering and Soil Science, University of Tennessee, Knoxville, TN, USA.
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35
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Liu F, Chen L, Zhang B, Wang G, Qin S, Yang Y. Ultraviolet radiation rather than inorganic nitrogen increases dissolved organic carbon biodegradability in a typical thermo-erosion gully on the Tibetan Plateau. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 627:1276-1284. [PMID: 30857092 DOI: 10.1016/j.scitotenv.2018.01.275] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 01/26/2018] [Accepted: 01/27/2018] [Indexed: 05/21/2023]
Abstract
Permafrost thaw could lead to frozen carbon (C) being laterally transferred to aquatic systems as dissolved organic carbon (DOC). If this part of DOC has high biodegradability, it could be decomposed during the delivery process, release greenhouse gases to the atmosphere and trigger positive C-climate feedback. Thermokarst is an abrupt permafrost thaw process that can enhance DOC export and also impact DOC processing through increased inorganic nitrogen (N) and ultraviolet (UV) light exposure. Especially on the Tibetan Plateau, where thermokarst develops widely and suffers from serious UV radiation and N limitation. However, it remains unclear how thermokarst-impacted biodegradable DOC (BDOC) responds to inorganic N addition and UV radiation. Here, we explored the responses of DOC concentration, composition and its biodegradability to inorganic N and UV amendments in a typical thermokarst on the Tibetan Plateau, by using laboratory incubations with spectral analyses (UV-visible absorption and three-dimensional fluorescence spectra) and parallel factor analyses. Our results showed that BDOC in thermokarst outflows was significantly higher than in reference water. Our results also revealed that inorganic N addition had no influence on thermokarst-impacted BDOC, whereas exposure to UV light significantly increased BDOC by as much as 2.3 times higher than the dark-control. Moreover, N addition and UV radiation did not generate additive effects on BDOC. Our results further illustrated that dissolved organic matter (DOM) composition explained more of the variability in BDOC, while the nutrients and other physicochemical properties played a minor role. Overall, these results imply that UV light rather than inorganic N significantly increases thermokarst-derived BDOC, potentially strengthening the positive permafrost C-climate feedback.
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Affiliation(s)
- Futing Liu
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Leiyi Chen
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Beibei Zhang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Guanqin Wang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shuqi Qin
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuanhe Yang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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36
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Chupakova AA, Chupakov AV, Neverova NV, Shirokova LS, Pokrovsky OS. Photodegradation of river dissolved organic matter and trace metals in the largest European Arctic estuary. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 622-623:1343-1352. [PMID: 29890600 DOI: 10.1016/j.scitotenv.2017.12.030] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2017] [Revised: 11/30/2017] [Accepted: 12/04/2017] [Indexed: 06/08/2023]
Abstract
Photo-induced degradation of dissolved organic matter (DOM) and organo-mineral colloids is one of the major factor responsible for transformation of DOM and dissolved metals in boreal and subarctic waters. In contrast to fairly good understanding of this process in inland waters of high latitude zone, the transformation of riverine DOM and associated trace element (TE) colloids in the Arctic estuaries remains virtually unknown. We incubated, under sunlight in outdoor pools, quartz reactors filled with mixtures of sterile filtered riverine and estuarine water. The water samples were collected in the estuarine zone of the largest European Arctic river, Severnaya Dvina. After 1month of exposure to sunlight, ≤5% change of dissolved organic carbon (DOC) concentration and specific ultraviolet (254nm) absorption occurred. This decrease was within the experimental uncertainty and it implies quite high resistance of river dissolved organic matter to photo-degradation in this estuary. Moreover, very low photodegradability of DOM in the freshwater point of the Severnaya Dvina River may require revisiting the current paradigm of the importance of DOC photolysis in large Arctic rivers. A novel finding was that the percentages of overall removal of Fe and some insoluble elements were quite similar across the full range of studied salinities, whereas the apparent rate of metal removal decreased with the increase of salinity. Overall, the salinity weakly impacted the removal of riverine DOC and metals in the estuarine water via photolysis and coagulation under sunlight. As a result, photoreactivity of DOM and dissolved metals in riverine end members corrected for estuarine dilution can be used to approximate the photolytic transformation of riverine material in the Arctic coastal zone.
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Affiliation(s)
- Anna A Chupakova
- N. Laverov Federal Center for Integrated Arctic Research, IEPS, Russian Academy of Science, Arkhangelsk, Russia
| | - Artem V Chupakov
- N. Laverov Federal Center for Integrated Arctic Research, IEPS, Russian Academy of Science, Arkhangelsk, Russia
| | - Natalia V Neverova
- N. Laverov Federal Center for Integrated Arctic Research, IEPS, Russian Academy of Science, Arkhangelsk, Russia
| | - Liudmila S Shirokova
- N. Laverov Federal Center for Integrated Arctic Research, IEPS, Russian Academy of Science, Arkhangelsk, Russia; Geoscience and Environment Toulouse, UMR 5563 CNRS, University of Toulouse, Toulouse, France
| | - Oleg S Pokrovsky
- Geoscience and Environment Toulouse, UMR 5563 CNRS, University of Toulouse, Toulouse, France; BIO-GEO-CLIM Laboratory, Tomsk State University, Tomsk, Russia.
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37
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Cui Q, Song C, Wang X, Shi F, Yu X, Tan W. Effects of warming on N 2O fluxes in a boreal peatland of Permafrost region, Northeast China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 616-617:427-434. [PMID: 29127796 DOI: 10.1016/j.scitotenv.2017.10.246] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 10/23/2017] [Accepted: 10/24/2017] [Indexed: 06/07/2023]
Abstract
Climate warming is expected to increasingly influence boreal peatlands and alter their greenhouse gases emissions. However, the effects of warming on N2O fluxes and the N2O budgets were ignored in boreal peatlands. Therefore, in a boreal peatland of permafrost zone in Northeast China, a simulated warming experiment was conducted to investigate the effects of warming on N2O fluxes in Betula. Fruticosa community (B. Fruticosa) and Ledum. palustre community (L. palustre) during the growing seasons from 2013 to 2015. Results showed that warming treatment increased air temperature at 1.5m aboveground and soil temperature at 5cm depth by 0.6°C and 2°C, respectively. The average seasonal N2O fluxes ranged from 6.62 to 9.34μgm-2h-1 in the warming plot and ranged from 0.41 to 4.55μgm-2h-1 in the control plots. Warming treatment increased N2O fluxes by 147% and transformed the boreal peatlands from a N2O sink to a source. The primary driving factors for N2O fluxes were soil temperature and active layer depth, whereas soil moisture showed a weak correlation with N2O fluxes. The results indicated that warming promoted N2O fluxes by increasing soil temperature and active layer depth in a boreal peatland of permafrost zone in Northeast China. Moreover, elevated N2O fluxes persisted in this region will potentially drive a noncarbon feedback to ongoing climate change.
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Affiliation(s)
- Qian Cui
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Changchun Song
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, PR China.
| | - Xianwei Wang
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, PR China
| | - Fuxi Shi
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, PR China
| | - Xueyang Yu
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Wenwen Tan
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, PR China
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38
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Ward CP, Nalven SG, Crump BC, Kling GW, Cory RM. Photochemical alteration of organic carbon draining permafrost soils shifts microbial metabolic pathways and stimulates respiration. Nat Commun 2017; 8:772. [PMID: 28974688 PMCID: PMC5626735 DOI: 10.1038/s41467-017-00759-2] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 07/25/2017] [Indexed: 11/10/2022] Open
Abstract
In sunlit waters, photochemical alteration of dissolved organic carbon (DOC) impacts the microbial respiration of DOC to CO2. This coupled photochemical and biological degradation of DOC is especially critical for carbon budgets in the Arctic, where thawing permafrost soils increase opportunities for DOC oxidation to CO2 in surface waters, thereby reinforcing global warming. Here we show how and why sunlight exposure impacts microbial respiration of DOC draining permafrost soils. Sunlight significantly increases or decreases microbial respiration of DOC depending on whether photo-alteration produces or removes molecules that native microbial communities used prior to light exposure. Using high-resolution chemical and microbial approaches, we show that rates of DOC processing by microbes are likely governed by a combination of the abundance and lability of DOC exported from land to water and produced by photochemical processes, and the capacity and timescale that microbial communities have to adapt to metabolize photo-altered DOC. The role of dissolved organic carbon (DOC) photo-alteration in the microbial respiration of DOC to CO2 is unclear. Here, the authors show that the impact of this mechanism depends on whether photo-alteration of DOC produces or removes molecules used by native microbial communities prior to light exposure.
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Affiliation(s)
- Collin P Ward
- Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, 48109-1048, USA.,Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, 02543-1050, USA
| | - Sarah G Nalven
- Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR, 97331-5503, USA
| | - Byron C Crump
- Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR, 97331-5503, USA
| | - George W Kling
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, 48109-1048, USA
| | - Rose M Cory
- Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, 48109-1048, USA.
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39
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Qu B, Sillanpää M, Li C, Kang S, Stubbins A, Yan F, Aho KS, Zhou F, Raymond PA. Aged dissolved organic carbon exported from rivers of the Tibetan Plateau. PLoS One 2017; 12:e0178166. [PMID: 28552976 PMCID: PMC5446113 DOI: 10.1371/journal.pone.0178166] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 05/08/2017] [Indexed: 11/18/2022] Open
Abstract
The role played by river networks in regional and global carbon cycle is receiving increasing attention. Despite the potential of radiocarbon measurements (14C) to elucidate sources and cycling of different riverine carbon pools, there remain large regions such as the climate-sensitive Tibetan Plateau for which no data are available. Here we provide new 14C data on dissolved organic carbon (DOC) from three large Asian rivers (the Yellow, Yangtze and Yarlung Tsangpo Rivers) running on the Tibetan Plateau and present the carbon transportation pattern in rivers of the plateau versus other river system in the world. Despite higher discharge rates during the high flow season, the DOC yield of Tibetan Plateau rivers (0.41 gC m-2 yr-1) was lower than most other rivers due to lower concentrations. Radiocarbon ages of the DOC were older/more depleted (511±294 years before present, yr BP) in the Tibetan rivers than those in Arctic and tropical rivers. A positive correlation between radiocarbon age and permafrost watershed coverage was observed, indicating that 14C-deplted/old carbon is exported from permafrost regions of the Tibetan Plateau during periods of high flow. This is in sharp contrast to permafrost regions of the Arctic which export 14C-enriched carbon during high discharge periods.
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Affiliation(s)
- Bin Qu
- Laboratory of Green Chemistry, Lappeenranta University of Technology, Mikkeli, Finland
| | - Mika Sillanpää
- Laboratory of Green Chemistry, Lappeenranta University of Technology, Mikkeli, Finland
- Department of Civil and Environmental Engineering, Florida International University, Miami, Florida, United States of America
| | - Chaoliu Li
- Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, China
- * E-mail:
| | - Shichang Kang
- State Key Laboratory of Cryospheric Sciences, Norwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, Gansu, China
- CAS Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing, China
| | - Aron Stubbins
- Skidaway Institute of Oceanography, Department of Marine Science, University of Georgia, Savannah, Georgia, United States of America
| | - Fangping Yan
- Laboratory of Green Chemistry, Lappeenranta University of Technology, Mikkeli, Finland
| | - Kelly Sue Aho
- Yale School of Forestry and Environmental Studies, Yale University, New Haven, Connecticut, United States of America
| | - Feng Zhou
- Sino-France Institute of Earth Systems Science, Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing, China
| | - Peter A. Raymond
- Yale School of Forestry and Environmental Studies, Yale University, New Haven, Connecticut, United States of America
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Degradation potentials of dissolved organic carbon (DOC) from thawed permafrost peat. Sci Rep 2017; 7:45811. [PMID: 28378792 PMCID: PMC5395014 DOI: 10.1038/srep45811] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 03/06/2017] [Indexed: 11/23/2022] Open
Abstract
Global warming can substantially affect the export of dissolved organic carbon (DOC) from peat-permafrost to aquatic systems. The direct degradability of such peat-derived DOC, however, is poorly constrained because previous permafrost thaw studies have mainly addressed mineral soil catchments or DOC pools that have already been processed in surface waters. We incubated peat cores from a palsa mire to compare an active layer and an experimentally thawed permafrost layer with regard to DOC composition and degradation potentials of pore water DOC. Our results show that DOC from the thawed permafrost layer had high initial degradation potentials compared with DOC from the active layer. In fact, the DOC that showed the highest bio- and photo-degradability, respectively, originated in the thawed permafrost layer. Our study sheds new light on the DOC composition of peat-permafrost directly upon thaw and suggests that past estimates of carbon-dioxide emissions from thawed peat permafrost may be biased as they have overlooked the initial mineralization potential of the exported DOC.
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42
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Tanski G, Lantuit H, Ruttor S, Knoblauch C, Radosavljevic B, Strauss J, Wolter J, Irrgang AM, Ramage J, Fritz M. Transformation of terrestrial organic matter along thermokarst-affected permafrost coasts in the Arctic. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 581-582:434-447. [PMID: 28088543 DOI: 10.1016/j.scitotenv.2016.12.152] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 12/22/2016] [Accepted: 12/22/2016] [Indexed: 05/21/2023]
Abstract
The changing climate in the Arctic has a profound impact on permafrost coasts, which are subject to intensified thermokarst formation and erosion. Consequently, terrestrial organic matter (OM) is mobilized and transported into the nearshore zone. Yet, little is known about the fate of mobilized OM before and after entering the ocean. In this study we investigated a retrogressive thaw slump (RTS) on Qikiqtaruk - Herschel Island (Yukon coast, Canada). The RTS was classified into an undisturbed, a disturbed (thermokarst-affected) and a nearshore zone and sampled systematically along transects. Samples were analyzed for total and dissolved organic carbon and nitrogen (TOC, DOC, TN, DN), stable carbon isotopes (δ13C-TOC, δ13C-DOC), and dissolved inorganic nitrogen (DIN), which were compared between the zones. C/N-ratios, δ13C signatures, and ammonium (NH4-N) concentrations were used as indicators for OM degradation along with biomarkers (n-alkanes, n-fatty acids, n-alcohols). Our results show that OM significantly decreases after disturbance with a TOC and DOC loss of 77 and 55% and a TN and DN loss of 53 and 48%, respectively. C/N-ratios decrease significantly, whereas NH4-N concentrations slightly increase in freshly thawed material. In the nearshore zone, OM contents are comparable to the disturbed zone. We suggest that the strong decrease in OM is caused by initial dilution with melted massive ice and immediate offshore transport via the thaw stream. In the mudpool and thaw stream, OM is subject to degradation, whereas in the slump floor the nitrogen decrease is caused by recolonizing vegetation. Within the nearshore zone of the ocean, heavier portions of OM are directly buried in marine sediments close to shore. We conclude that RTS have profound impacts on coastal environments in the Arctic. They mobilize nutrients from permafrost, substantially decrease OM contents and provide fresh water and nutrients at a point source.
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Affiliation(s)
- George Tanski
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Periglacial Research Unit, Potsdam, Germany; Potsdam University, Institute of Earth and Environmental Sciences, Potsdam, Germany.
| | - Hugues Lantuit
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Periglacial Research Unit, Potsdam, Germany; Potsdam University, Institute of Earth and Environmental Sciences, Potsdam, Germany.
| | - Saskia Ruttor
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Periglacial Research Unit, Potsdam, Germany; Potsdam University, Institute of Earth and Environmental Sciences, Potsdam, Germany.
| | | | - Boris Radosavljevic
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Periglacial Research Unit, Potsdam, Germany; Potsdam University, Institute of Earth and Environmental Sciences, Potsdam, Germany.
| | - Jens Strauss
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Periglacial Research Unit, Potsdam, Germany.
| | - Juliane Wolter
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Periglacial Research Unit, Potsdam, Germany; Potsdam University, Institute of Earth and Environmental Sciences, Potsdam, Germany.
| | - Anna M Irrgang
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Periglacial Research Unit, Potsdam, Germany; Potsdam University, Institute of Earth and Environmental Sciences, Potsdam, Germany.
| | - Justine Ramage
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Periglacial Research Unit, Potsdam, Germany; Potsdam University, Institute of Earth and Environmental Sciences, Potsdam, Germany.
| | - Michael Fritz
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Periglacial Research Unit, Potsdam, Germany.
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43
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Environmental effects of ozone depletion and its interactions with climate change: Progress report, 2016. Photochem Photobiol Sci 2017; 16:107-145. [PMID: 28124708 PMCID: PMC6400464 DOI: 10.1039/c7pp90001e] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Accepted: 01/05/2017] [Indexed: 12/12/2022]
Abstract
The Parties to the Montreal Protocol are informed by three Panels of experts. One of these is the Environmental Effects Assessment Panel (EEAP), which deals with two focal issues. The first focus is the effects of UV radiation on human health, animals, plants, biogeochemistry, air quality, and materials. The second focus is on interactions between UV radiation and global climate change and how these may affect humans and the environment. When considering the effects of climate change, it has become clear that processes resulting in changes in stratospheric ozone are more complex than previously believed. As a result of this, human health and environmental issues will be longer-lasting and more regionally variable. Like the other Panels, the EEAP produces a detailed report every four years; the most recent was published as a series of seven papers in 2015 (Photochem. Photobiol. Sci., 2015, 14, 1-184). In the years in between, the EEAP produces less detailed and shorter Progress Reports of the relevant scientific findings. The most recent of these was for 2015 (Photochem. Photobiol. Sci., 2016, 15, 141-147). The present Progress Report for 2016 assesses some of the highlights and new insights with regard to the interactive nature of the direct and indirect effects of UV radiation, atmospheric processes, and climate change. The more detailed Quadrennial Assessment will be made available in 2018.
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44
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Roiha T, Peura S, Cusson M, Rautio M. Allochthonous carbon is a major regulator to bacterial growth and community composition in subarctic freshwaters. Sci Rep 2016; 6:34456. [PMID: 27686416 PMCID: PMC5043279 DOI: 10.1038/srep34456] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 09/14/2016] [Indexed: 11/09/2022] Open
Abstract
In the subarctic region, climate warming and permafrost thaw are leading to emergence of ponds and to an increase in mobility of catchment carbon. As carbon of terrestrial origin is increasing in subarctic freshwaters the resource pool supporting their microbial communities and metabolism is changing, with consequences to overall aquatic productivity. By sampling different subarctic water bodies for a one complete year we show how terrestrial and algal carbon compounds vary in a range of freshwaters and how differential organic carbon quality is linked to bacterial metabolism and community composition. We show that terrestrial drainage and associated nutrients supported higher bacterial growth in ponds and river mouths that were influenced by fresh terrestrial carbon than in large lakes with carbon from algal production. Bacterial diversity, however, was lower at sites influenced by terrestrial carbon inputs. Bacterial community composition was highly variable among different water bodies and especially influenced by concentrations of dissolved organic carbon (DOC), fulvic acids, proteins and nutrients. Furthermore, a distinct preference was found for terrestrial vs. algal carbon among certain bacterial tribes. The results highlight the contribution of the numerous ponds to cycling of terrestrial carbon in the changing subarctic and arctic regions.
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Affiliation(s)
- Toni Roiha
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland.,Département des sciences fondamentales, Université du Québec à Chicoutimi, Chicoutimi, Quebec, Canada
| | - Sari Peura
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland.,Department of Ecology and Genetics, Limnology, Uppsala University, Uppsala, Sweden
| | - Mathieu Cusson
- Département des sciences fondamentales, Université du Québec à Chicoutimi, Chicoutimi, Quebec, Canada
| | - Milla Rautio
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland.,Département des sciences fondamentales, Université du Québec à Chicoutimi, Chicoutimi, Quebec, Canada.,Centre for Northern Studies (CEN), Laval University, Quebec City, Quebec, Canada.,Group for Interuniversity Research in Limnology and aquatic environment (GRIL), University of Montreal, Montreal, Quebec, Canada
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45
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Sulzberger B, Arey JS. Impacts of Polar Changes on the UV-induced Mineralization of Terrigenous Dissolved Organic Matter. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:6621-6631. [PMID: 27110903 DOI: 10.1021/acs.est.5b05994] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Local climates in the Northern and Southern Hemisphere are influenced by Arctic Amplification and by interactions of the Antarctic ozone hole with climate change, respectively. Polar changes may affect hydroclimatic conditions in temperate regions, for example, by increasing the length and intensity of precipitation events at Northern Hemisphere midlatitudes. Additionally, global warming has led to the thawing of ancient permafrost soils, particularly in Arctic regions, due to Arctic Amplification. Both heavy precipitation events and thawing of permafrost are increasing the net transfer of terrestrially derived dissolved organic matter (DOM) from land to surface waters. In aquatic ecosystems, UV-induced oxidation of terrigenous DOM (tDOM) produces atmospheric CO2 and this process is one of several mechanisms by which natural organic matter in aquatic and soil environments may play an important role in climate feedbacks. The Arctic is particularly affected by these processes: for example, melting of Arctic sea ice allows solar UV radiation to penetrate into the ice-free Arctic Ocean and to cause photochemical reactions that result in bleaching and mineralization of tDOM. Open questions, in addition to those shown in the Graphical Abstract, remain regarding the resulting contributions of tDOM photomineralization to CO2 production and global warming.
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Affiliation(s)
- Barbara Sulzberger
- Academic Guest, Eawag: Swiss Federal Institute of Aquatic Science and Technology , P.O. Box 611, CH-8600 Duebendorf, Switzerland
| | - J Samuel Arey
- Environmental Chemistry Modeling Laboratory, Department of Architecture, Civil and Environmental Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), Ecole Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne, Switzerland
- Department of Environmental Chemistry, Eawag: Swiss Federal Institute of Aquatic Science and Technology , P.O. Box 611, CH-8600 Duebendorf, Switzerland
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46
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Ward CP, Cory RM. Complete and Partial Photo-oxidation of Dissolved Organic Matter Draining Permafrost Soils. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:3545-53. [PMID: 26910810 DOI: 10.1021/acs.est.5b05354] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Photochemical degradation of dissolved organic matter (DOM) to carbon dioxide (CO2) and partially oxidized compounds is an important component of the carbon cycle in the Arctic. Thawing permafrost soils will change the chemical composition of DOM exported to arctic surface waters, but the molecular controls on DOM photodegradation remain poorly understood, making it difficult to predict how inputs of thawing permafrost DOM may alter its photodegradation. To address this knowledge gap, we quantified the susceptibility of DOM draining the shallow organic mat and the deeper permafrost layer of arctic soils to complete and partial photo-oxidation and investigated changes in the chemical composition of each DOM source following sunlight exposure. Permafrost and organic mat DOM had similar lability to photomineralization despite substantial differences in initial chemical composition. Concurrent losses of carboxyl moieties and shifts in chemical composition during photodegradation indicated that photodecarboxylation could account for 40-90% of DOM photomineralized to CO2. Permafrost DOM had a higher susceptibility to partial photo-oxidation compared to organic mat DOM, potentially due to a lower abundance of phenolic moieties with antioxidant properties. These results suggest that photodegradation will likely continue to be an important control on DOM fate in arctic freshwaters as the climate warms and permafrost soils thaw.
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Affiliation(s)
- Collin P Ward
- Department of Earth and Environmental Sciences, 2534 C.C. Little Building, 1100 North University Avenue, University of Michigan , Ann Arbor, Michigan 48109, United States
| | - Rose M Cory
- Department of Earth and Environmental Sciences, 2534 C.C. Little Building, 1100 North University Avenue, University of Michigan , Ann Arbor, Michigan 48109, United States
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Abbott BW, Jones JB. Permafrost collapse alters soil carbon stocks, respiration, CH4 , and N2O in upland tundra. GLOBAL CHANGE BIOLOGY 2015; 21:4570-4587. [PMID: 26301544 DOI: 10.1111/gcb.13069] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2015] [Accepted: 08/12/2015] [Indexed: 06/04/2023]
Abstract
Release of greenhouse gases from thawing permafrost is potentially the largest terrestrial feedback to climate change and one of the most likely to occur; however, estimates of its strength vary by a factor of thirty. Some of this uncertainty stems from abrupt thaw processes known as thermokarst (permafrost collapse due to ground ice melt), which alter controls on carbon and nitrogen cycling and expose organic matter from meters below the surface. Thermokarst may affect 20-50% of tundra uplands by the end of the century; however, little is known about the effect of different thermokarst morphologies on carbon and nitrogen release. We measured soil organic matter displacement, ecosystem respiration, and soil gas concentrations at 26 upland thermokarst features on the North Slope of Alaska. Features included the three most common upland thermokarst morphologies: active-layer detachment slides, thermo-erosion gullies, and retrogressive thaw slumps. We found that thermokarst morphology interacted with landscape parameters to determine both the initial displacement of organic matter and subsequent carbon and nitrogen cycling. The large proportion of ecosystem carbon exported off-site by slumps and slides resulted in decreased ecosystem respiration postfailure, while gullies removed a smaller portion of ecosystem carbon but strongly increased respiration and N2 O concentration. Elevated N2 O in gully soils persisted through most of the growing season, indicating sustained nitrification and denitrification in disturbed soils, representing a potential noncarbon permafrost climate feedback. While upland thermokarst formation did not substantially alter redox conditions within features, it redistributed organic matter into both oxic and anoxic environments. Across morphologies, residual organic matter cover, and predisturbance respiration explained 83% of the variation in respiration response. Consistent differences between upland thermokarst types may contribute to the incorporation of this nonlinear process into projections of carbon and nitrogen release from degrading permafrost.
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Affiliation(s)
- Benjamin W Abbott
- OSUR, CNRS, UMR 6553 ECOBIO, Université de Rennes 1, Rennes, France
- Department of Biology and Wildlife and Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK, USA
| | - Jeremy B Jones
- Department of Biology and Wildlife and Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK, USA
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Pearce AR, Rastetter EB, Kwiatkowski BL, Bowden WB, Mack MC, Jiang Y. Recovery of arctic tundra from thermal erosion disturbance is constrained by nutrient accumulation: a modeling analysis. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2015; 25:1271-89. [PMID: 26485955 DOI: 10.1890/14-1323.1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Abstract. We calibrated the Multiple Element Limitation (MEL) model to Alaskan arctic tundra to simulate recovery of thermal erosion features (TEFs) caused by permafrost thaw and mass wasting. TEFs could significantly alter regional carbon (C) and nutrient budgets because permafrost soils contain large stocks of soil organic matter (SOM) and TEFs are expected to become more frequent as the climate warms. We simulated recovery following TEF stabilization and did not address initial, short-term losses of C and nutrients during TEF formation. To capture the variability among and within TEFs, we modeled a range of post-stabilization conditions by varying the initial size of SOM stocks and nutrient supply rates. Simulations indicate that nitrogen (N) losses after the TEF stabilizes are small, but phosphorus (P) losses continue. Vegetation biomass recovered 90% of its undisturbed C, N, and P stocks in 100 years using nutrients mineralized from SOM. Because of low litter inputs but continued decomposition, younger SOM continued to be lost for 10 years after the TEF began to recover, but recovered to about 84% of its undisturbed amount in 100 years. The older recalcitrant SOM in mineral soil continued to be lost throughout the 100-year simulation. Simulations suggest that biomass recovery depended on the amount of SOM remaining after disturbance. Recovery was initially limited by the photosynthetic capacity of vegetation but became co-limited by N and P once a plant canopy developed. Biomass and SOM recovery was enhanced by increasing nutrient supplies, but the magnitude, source, and controls on these supplies are poorly understood. Faster mineralization of nutrients from SOM (e.g., by warming) enhanced vegetation recovery but delayed recovery of SOM. Taken together, these results suggest that although vegetation and surface SOM on TEFs recovered quickly (25 and 100 years, respectively), the recovery of deep, mineral soil SOM took centuries and represented a major ecosystem C loss.
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49
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Climate change and the permafrost carbon feedback. Nature 2015; 520:171-9. [DOI: 10.1038/nature14338] [Citation(s) in RCA: 1830] [Impact Index Per Article: 203.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Accepted: 02/12/2015] [Indexed: 11/08/2022]
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50
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Lara MJ, McGuire AD, Euskirchen ES, Tweedie CE, Hinkel KM, Skurikhin AN, Romanovsky VE, Grosse G, Bolton WR, Genet H. Polygonal tundra geomorphological change in response to warming alters future CO2 and CH4 flux on the Barrow Peninsula. GLOBAL CHANGE BIOLOGY 2015; 21:1634-1651. [PMID: 25258295 DOI: 10.1111/gcb.12757] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Accepted: 09/09/2014] [Indexed: 06/03/2023]
Abstract
The landscape of the Barrow Peninsula in northern Alaska is thought to have formed over centuries to millennia, and is now dominated by ice-wedge polygonal tundra that spans drained thaw-lake basins and interstitial tundra. In nearby tundra regions, studies have identified a rapid increase in thermokarst formation (i.e., pits) over recent decades in response to climate warming, facilitating changes in polygonal tundra geomorphology. We assessed the future impact of 100 years of tundra geomorphic change on peak growing season carbon exchange in response to: (i) landscape succession associated with the thaw-lake cycle; and (ii) low, moderate, and extreme scenarios of thermokarst pit formation (10%, 30%, and 50%) reported for Alaskan arctic tundra sites. We developed a 30 × 30 m resolution tundra geomorphology map (overall accuracy:75%; Kappa:0.69) for our ~1800 km² study area composed of ten classes; drained slope, high center polygon, flat-center polygon, low center polygon, coalescent low center polygon, polygon trough, meadow, ponds, rivers, and lakes, to determine their spatial distribution across the Barrow Peninsula. Land-atmosphere CO2 and CH4 flux data were collected for the summers of 2006-2010 at eighty-two sites near Barrow, across the mapped classes. The developed geomorphic map was used for the regional assessment of carbon flux. Results indicate (i) at present during peak growing season on the Barrow Peninsula, CO2 uptake occurs at -902.3 10(6) gC-CO2 day(-1) (uncertainty using 95% CI is between -438.3 and -1366 10(6) gC-CO2 day(-1)) and CH4 flux at 28.9 10(6) gC-CH4 day(-1) (uncertainty using 95% CI is between 12.9 and 44.9 10(6) gC-CH4 day(-1)), (ii) one century of future landscape change associated with the thaw-lake cycle only slightly alter CO2 and CH4 exchange, while (iii) moderate increases in thermokarst pits would strengthen both CO2 uptake (-166.9 10(6) gC-CO2 day(-1)) and CH4 flux (2.8 10(6) gC-CH4 day(-1)) with geomorphic change from low to high center polygons, cumulatively resulting in an estimated negative feedback to warming during peak growing season.
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Affiliation(s)
- Mark J Lara
- Institute of Arctic Biology, University of Alaska, Fairbanks, AK, 99775, USA
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