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Shaaban M. Microbial pathways of nitrous oxide emissions and mitigation approaches in drylands. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 354:120393. [PMID: 38364533 DOI: 10.1016/j.jenvman.2024.120393] [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: 11/10/2023] [Revised: 01/07/2024] [Accepted: 02/11/2024] [Indexed: 02/18/2024]
Abstract
Drylands refer to water scarcity and low nutrient levels, and their plant and biocrust distribution is highly diverse, making the microbial processes that shape dryland functionality particularly unique compared to other ecosystems. Drylands are constraint for sustainable agriculture and risk for food security, and expected to increase over time. Nitrous oxide (N2O), a potent greenhouse gas with ozone reduction potential, is significantly influenced by microbial communities in drylands. However, our understanding of the biological mechanisms and processes behind N2O emissions in these areas is limited, despite the fact that they highly account for total gaseous nitrogen (N) emissions on Earth. This review aims to illustrate the important biological pathways and microbial players that regulate N2O emissions in drylands, and explores how these pathways might be influenced by global changes for example N deposition, extreme weather events, and climate warming. Additionally, we propose a theoretical framework for manipulating the dryland microbial community to effectively reduce N2O emissions using evolving techniques that offer inordinate specificity and efficacy. By combining expertise from different disciplines, these exertions will facilitate the advancement of innovative and environmentally friendly microbiome-based solutions for future climate change vindication approaches.
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Affiliation(s)
- Muhammad Shaaban
- College of Agriculture, Henan University of Science and Technology, Luoyang, China.
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2
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Chen Y, Han M, Qin W, Hou Y, Zhang Z, Zhu B. Effects of whole-soil warming on CH 4 and N 2 O fluxes in an alpine grassland. GLOBAL CHANGE BIOLOGY 2024; 30:e17033. [PMID: 38273530 DOI: 10.1111/gcb.17033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 10/23/2023] [Indexed: 01/27/2024]
Abstract
Global climate warming could affect the methane (CH4 ) and nitrous oxide (N2 O) fluxes between soils and the atmosphere, but how CH4 and N2 O fluxes respond to whole-soil warming is unclear. Here, we for the first time investigated the effects of whole-soil warming on CH4 and N2 O fluxes in an alpine grassland ecosystem on the Tibetan Plateau, and also studied the effects of experimental warming on CH4 and N2 O fluxes across terrestrial ecosystems through a global-scale meta-analysis. The whole-soil warming (0-100 cm, +4°C) significantly elevated soil N2 O emission by 101%, but had a minor effect on soil CH4 uptake. However, the meta-analysis revealed that experimental warming did not significantly alter CH4 and N2 O fluxes, and it may be that most field warming experiments could only heat the surface soils. Moreover, the warming-induced higher plant litter and available N in soils may be the main reason for the higher N2 O emission under whole-soil warming in the alpine grassland. We need to pay more attention to the long-term response of greenhouse gases (including CH4 and N2 O fluxes) from different soil depths to whole-soil warming over year-round, which could help us more accurately assess and predict the ecosystem-climate feedback under realistic warming scenarios in the future.
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Affiliation(s)
- Ying Chen
- College of Urban and Environmental Sciences, and Key Laboratory for Earth Surface Processes of the Ministry of Education, Institute of Ecology, Peking University, Beijing, China
| | - Mengguang Han
- College of Urban and Environmental Sciences, and Key Laboratory for Earth Surface Processes of the Ministry of Education, Institute of Ecology, Peking University, Beijing, China
| | - Wenkuan Qin
- College of Urban and Environmental Sciences, and Key Laboratory for Earth Surface Processes of the Ministry of Education, Institute of Ecology, Peking University, Beijing, China
| | - Yanhui Hou
- College of Urban and Environmental Sciences, and Key Laboratory for Earth Surface Processes of the Ministry of Education, Institute of Ecology, Peking University, Beijing, China
| | - Zhenhua Zhang
- Qinghai Haibei National Field Research Station of Alpine Grassland Ecosystem, and Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, China
| | - Biao Zhu
- College of Urban and Environmental Sciences, and Key Laboratory for Earth Surface Processes of the Ministry of Education, Institute of Ecology, Peking University, Beijing, China
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3
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Fry EL, Ashworth D, Allen KAJ, Chardon NI, Rixen C, Björkman MP, Björk RG, Stålhandske T, Molau M, Locke-King B, Cantillon I, McDonald C, Liu H, De Vries FT, Ostle NJ, Singh BK, Bardgett RD. Vegetation type, not the legacy of warming, modifies the response of microbial functional genes and greenhouse gas fluxes to drought in Oro-Arctic and alpine regions. FEMS Microbiol Ecol 2023; 99:fiad145. [PMID: 37951295 PMCID: PMC10673709 DOI: 10.1093/femsec/fiad145] [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: 09/20/2023] [Revised: 10/31/2023] [Accepted: 11/09/2023] [Indexed: 11/13/2023] Open
Abstract
Climate warming and summer droughts alter soil microbial activity, affecting greenhouse gas (GHG) emissions in Arctic and alpine regions. However, the long-term effects of warming, and implications for future microbial resilience, are poorly understood. Using one alpine and three Arctic soils subjected to in situ long-term experimental warming, we simulated drought in laboratory incubations to test how microbial functional-gene abundance affects fluxes in three GHGs: carbon dioxide, methane, and nitrous oxide. We found that responses of functional gene abundances to drought and warming are strongly associated with vegetation type and soil carbon. Our sites ranged from a wet, forb dominated, soil carbon-rich systems to a drier, soil carbon-poor alpine site. Resilience of functional gene abundances, and in turn methane and carbon dioxide fluxes, was lower in the wetter, carbon-rich systems. However, we did not detect an effect of drought or warming on nitrous oxide fluxes. All gene-GHG relationships were modified by vegetation type, with stronger effects being observed in wetter, forb-rich soils. These results suggest that impacts of warming and drought on GHG emissions are linked to a complex set of microbial gene abundances and may be habitat-specific.
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Affiliation(s)
- Ellen L Fry
- School of Earth and Environment Sciences, University of Manchester, Oxford Road, Manchester, M13 9PL, United Kingdom
- Department of Biology, Edge Hill University, St Helens Road, Ormskirk, Lancashire, L39 4AP, United Kingdom
| | - Deborah Ashworth
- School of Earth and Environment Sciences, University of Manchester, Oxford Road, Manchester, M13 9PL, United Kingdom
| | - Kimberley A J Allen
- School of Earth and Environment Sciences, University of Manchester, Oxford Road, Manchester, M13 9PL, United Kingdom
| | - Nathalie Isabelle Chardon
- Biodiversity Research Centre, University of British Columbia, 2212 Main Mall Vancouver, BC V6T 1Z4, Canada
| | - Christian Rixen
- WSL Institute for Snow and Avalanche Research SLF, Flüelastrasse 11, CH-7260 Davos Dorf, Switzerland
- Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Flüelastrasse 11, 7260 Davos Dorf, Switzerland
- Climate Change, Extremes and Natural Hazards in Alpine Regions Research Centre CERC, Flüelastrasse 11, 7260 Davos Dorf, Switzerland
| | - Mats P Björkman
- Department of Earth Sciences, University of Gothenburg, Box 100 405 30 Gothenburg, Gothenburg, Sweden
- Gothenburg Global Biodiversity Centre, Box 100 405 30 Gothenburg, Gothenburg, Sweden
| | - Robert G Björk
- Department of Earth Sciences, University of Gothenburg, Box 100 405 30 Gothenburg, Gothenburg, Sweden
- Gothenburg Global Biodiversity Centre, Box 100 405 30 Gothenburg, Gothenburg, Sweden
| | - Thomas Stålhandske
- Department of Earth Sciences, University of Gothenburg, Box 100 405 30 Gothenburg, Gothenburg, Sweden
| | - Mathias Molau
- Department of Earth Sciences, University of Gothenburg, Box 100 405 30 Gothenburg, Gothenburg, Sweden
| | - Brady Locke-King
- Department of Biology, Edge Hill University, St Helens Road, Ormskirk, Lancashire, L39 4AP, United Kingdom
| | - Isabelle Cantillon
- Department of Biology, Edge Hill University, St Helens Road, Ormskirk, Lancashire, L39 4AP, United Kingdom
| | - Catriona McDonald
- Hawkesbury Institute for the Environment, Western Sydney University, Bourke Street, Penrith, NSW, Australia
| | - Hongwei Liu
- Hawkesbury Institute for the Environment, Western Sydney University, Bourke Street, Penrith, NSW, Australia
| | - Franciska T De Vries
- Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, 1090 GE Amsterdam, the Netherlands
| | - Nick J Ostle
- Lancaster Environment Centre, Lancaster University, Bailrigg, Lancaster, LA1 4YW, United Kingdom
| | - Brajesh K Singh
- Hawkesbury Institute for the Environment, Western Sydney University, Bourke Street, Penrith, NSW, Australia
- Global Centre for Land-Based Innovation, Western Sydney University, Bourke Street, Penrith, NSW, Australia
| | - Richard D Bardgett
- School of Earth and Environment Sciences, University of Manchester, Oxford Road, Manchester, M13 9PL, United Kingdom
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Pérez-Uz B, Galfione VC, Ochoa-Hueso R, Martín-Cereceda M. Protist Diversity Responses to Experimental N Deposition in Biological Crusts of a Semiarid Mediterranean Ecosystem. Protist 2023; 174:125929. [PMID: 36455480 DOI: 10.1016/j.protis.2022.125929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 11/03/2022] [Accepted: 11/04/2022] [Indexed: 11/17/2022]
Abstract
Biological soil crusts (BSC) are associations of different macro and microorganisms and aggregated soil particles located on the surface of soils in many different habitats. BSC harbour a diverse and complex community of ciliates and testate amoebae. These phagotrophic protists play an important role in C and N recycling in soil ecosystems but have not been frequently studied in BSC. In this context, the effects of three increasing N inputs on ciliates and testate amoebae in crusts from a semi-arid Mediterranean ecosystem were evaluated. A field experiment with artificial N-deposition was designed to mimic the effects caused by anthropogenic N depositions. The results have shown that the protist populations of these semi-arid Mediterranean environments have lower species richness than other soil environments. The increase in N produces a net loss of diversity in the populations studied and shifts in the community structure. It has also been shown that some ciliates and testate amoebae, due to their population responses to increased N concentrations, could potentially be used as bio-indicators of N contamination in these BSCs.
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Affiliation(s)
- Blanca Pérez-Uz
- Dept. Genética, Fisiología y Microbiología, Fac. Ciencias Biológicas, Universidad Complutense de Madrid, Madrid, Spain.
| | - Virginia C Galfione
- Dept. Genética, Fisiología y Microbiología, Fac. Ciencias Biológicas, Universidad Complutense de Madrid, Madrid, Spain
| | - Raul Ochoa-Hueso
- Instituto de Investigación Vitivinicola y Agroalimentaria, Universidad de Cádiz, Puerto Real, Spain
| | - Mercedes Martín-Cereceda
- Dept. Genética, Fisiología y Microbiología, Fac. Ciencias Biológicas, Universidad Complutense de Madrid, Madrid, Spain
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5
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Richardson AD, Kong GV, Taylor KM, Le Moine JM, Bowker MA, Barber JJ, Basler D, Carbone MS, Hayer M, Koch GW, Salvatore MR, Sonnemaker AW, Trilling DE. Soil-atmosphere fluxes of CO2, CH4, and N2O across an experimentally-grown, successional gradient of biocrust community types. Front Microbiol 2022; 13:979825. [PMID: 36225383 PMCID: PMC9549369 DOI: 10.3389/fmicb.2022.979825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 09/07/2022] [Indexed: 11/13/2022] Open
Abstract
Biological soil crusts (biocrusts) are critical components of dryland and other ecosystems worldwide, and are increasingly recognized as novel model ecosystems from which more general principles of ecology can be elucidated. Biocrusts are often diverse communities, comprised of both eukaryotic and prokaryotic organisms with a range of metabolic lifestyles that enable the fixation of atmospheric carbon and nitrogen. However, how the function of these biocrust communities varies with succession is incompletely characterized, especially in comparison to more familiar terrestrial ecosystem types such as forests. We conducted a greenhouse experiment to investigate how community composition and soil-atmosphere trace gas fluxes of CO2, CH4, and N2O varied from early-successional light cyanobacterial biocrusts to mid-successional dark cyanobacteria biocrusts and late-successional moss-lichen biocrusts and as biocrusts of each successional stage matured. Cover type richness increased as biocrusts developed, and richness was generally highest in the late-successional moss-lichen biocrusts. Microbial community composition varied in relation to successional stage, but microbial diversity did not differ significantly among stages. Net photosynthetic uptake of CO2 by each biocrust type also increased as biocrusts developed but tended to be moderately greater (by up to ≈25%) for the mid-successional dark cyanobacteria biocrusts than the light cyanobacterial biocrusts or the moss-lichen biocrusts. Rates of soil C accumulation were highest for the dark cyanobacteria biocrusts and light cyanobacteria biocrusts, and lowest for the moss-lichen biocrusts and bare soil controls. Biocrust CH4 and N2O fluxes were not consistently distinguishable from the same fluxes measured from bare soil controls; the measured rates were also substantially lower than have been reported in previous biocrust studies. Our experiment, which uniquely used greenhouse-grown biocrusts to manipulate community composition and accelerate biocrust development, shows how biocrust function varies along a dynamic gradient of biocrust successional stages.
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Affiliation(s)
- Andrew D. Richardson
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, United States
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ, United States
- *Correspondence: Andrew D. Richardson,
| | - Gary V. Kong
- Department of Astronomy and Planetary Science, Northern Arizona University, Flagstaff, AZ, United States
- University of California, Santa Barbara, CA, United States
| | - Katrina M. Taylor
- Department of Astronomy and Planetary Science, Northern Arizona University, Flagstaff, AZ, United States
- Department of Astronomy and Astrophysics, The Pennsylvania State University, State College, PA, United States
| | - James M. Le Moine
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, United States
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ, United States
| | - Matthew A. Bowker
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, United States
- School of Forestry, Northern Arizona University, Flagstaff, AZ, United States
| | - Jarrett J. Barber
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ, United States
| | - David Basler
- Department of Environmental Sciences–Botany, University of Basel, Basel, Switzerland
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
| | - Mariah S. Carbone
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, United States
| | - Michaela Hayer
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, United States
| | - George W. Koch
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, United States
| | - Mark R. Salvatore
- Department of Astronomy and Planetary Science, Northern Arizona University, Flagstaff, AZ, United States
| | - A. Wesley Sonnemaker
- Department of Astronomy and Planetary Science, Northern Arizona University, Flagstaff, AZ, United States
- Lowell Observatory, Flagstaff, AZ, United States
| | - David E. Trilling
- Department of Astronomy and Planetary Science, Northern Arizona University, Flagstaff, AZ, United States
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6
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Hu Y, Xu B, Wang Y, He Z, Zhang P, Wang G. Reference for different sensitivities of greenhouse gases effluxes to warming climate among types of desert biological soil crust. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 830:154805. [PMID: 35341852 DOI: 10.1016/j.scitotenv.2022.154805] [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: 11/16/2021] [Revised: 03/19/2022] [Accepted: 03/20/2022] [Indexed: 06/14/2023]
Abstract
There is much uncertainty about how climate warming will impact greenhouse gases (GHG) budget in dry environments due to the lack of available data for desert biocrust soil. We implemented a 2.5-year field measurement of CO2, CH4 and N2O effluxes in cyanobacteria-dominated, moss-dominated and mixed (cyanobacteria, moss and lichen) biocrust soils using open-top-chambers to simulate climate warming (1.2 °C on average). Desert biocrust soils generally acted as a weak sink of atmospheric CH4 and N2O. Although warming effects on daily CO2, CH4, and N2O effluxes varied depending on sampling date and biocrust soil, there was no significant difference in daily, monthly and seasonal average CO2, CH4 and N2O effluxes between warming and control in most cases for three biocrust soils. However, warming caused a marginal (p = 0.06) decrease (14.2%) in annual accumulative CO2 efflux in moss-dominated biocrust soil due to the drought effects caused by warming indirectly and OTC sheltering of precipitation directly, while there was no significant difference between warming and control for cyanobacteria-dominated and mixed biocrust soils, implying a neutral response of GHG effluxes to climate warming. These results suggest that the GHG budget in arid desert biocrust soil would not be significantly changed in the warmer future when the direct negative effects of drought on CO2 effluxes were excluded. Therefore, a marginal decrease of accumulative CO2 effluxes in response to warming coupled with drought for moss-dominated biocrust soil might offer a weak negative feedback to warming and drier climate change pattern.
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Affiliation(s)
- Yigang Hu
- Shapotou Desert Experiment and Research Station, Northwest Institute of Eco-Environmental and Resources, Chinese Academy of Sciences, Lanzhou, China.
| | - Bingxin Xu
- Shapotou Desert Experiment and Research Station, Northwest Institute of Eco-Environmental and Resources, Chinese Academy of Sciences, Lanzhou, China; University of Chinese Academy of Sciences, Beijing, China
| | - Yani Wang
- Shapotou Desert Experiment and Research Station, Northwest Institute of Eco-Environmental and Resources, Chinese Academy of Sciences, Lanzhou, China; University of Chinese Academy of Sciences, Beijing, China
| | - Zhenzi He
- Shapotou Desert Experiment and Research Station, Northwest Institute of Eco-Environmental and Resources, Chinese Academy of Sciences, Lanzhou, China; University of Chinese Academy of Sciences, Beijing, China
| | - Peng Zhang
- Shapotou Desert Experiment and Research Station, Northwest Institute of Eco-Environmental and Resources, Chinese Academy of Sciences, Lanzhou, China
| | - Guojie Wang
- Eastern Oregon Agriculture and Natural Resource Program, Oregon State University, La Grande, OR, USA
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Xiao J, Lan S, Zhang Z, Yang L, Qian L, Xia L, Song S, Farías ME, Torres RM, Wu L. Physical Disturbance Reduces Cyanobacterial Relative Abundance and Substrate Metabolism Potential of Biological Soil Crusts on a Gold Mine Tailing of Central China. Front Microbiol 2022; 13:811039. [PMID: 35464943 PMCID: PMC9019783 DOI: 10.3389/fmicb.2022.811039] [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: 11/08/2021] [Accepted: 02/21/2022] [Indexed: 11/19/2022] Open
Abstract
As the critical ecological engineers, biological soil crusts (biocrusts) are considered to play essential roles in improving substrate conditions during ecological rehabilitation processes. Physical disturbance, however, often leads to the degradation of biocrusts, and it remains unclear how the physical disturbance affects biocrust microorganisms and their related metabolism. In this study, the photosynthetic biomass (indicated by chlorophyll a), nutrients, enzyme activities, and bacterial communities of biocrusts were investigated in a gold mine tailing of Central China to evaluate the impact of physical disturbance on biocrusts during the rehabilitation process of gold mine tailings. The results show that physical disturbance significantly reduced the photosynthetic biomass, nutrient contents (organic carbon, ammonium nitrogen, nitrate nitrogen, and total phosphorus), and enzyme activities (β-glucosidase, sucrase, nitrogenase, neutral phosphatase, and urease) of biocrusts in the mine tailings. Furthermore, 16S rDNA sequencing showed that physical disturbance strongly changed the composition, structure, and interactions of the bacterial community, leading to a shift from a cyanobacteria dominated community to a heterotrophic bacteria (proteobacteria, actinobacteria, and acidobacteria) dominated community and a more complex bacterial network (higher complexity, nodes, and edges). Altogether, our results show that the biocrusts dominated by cyanobacteria could also develop in the tailings of humid region, and the dominants (e.g., Microcoleus) were the same as those from dryland biocrusts; nevertheless, physical disturbance significantly reduced cyanobacterial relative abundance in biocrusts. Based on our findings, we propose the future work on cyanobacterial inoculation (e.g., Microcoleus), which is expected to promote substrate metabolism and accumulation, ultimately accelerating the development of biocrusts and the subsequent ecological restoration of tailings.
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Affiliation(s)
- Jingshang Xiao
- School of Resources and Environmental Engineering, Wuhan University of Technology, Wuhan, China
| | - Shubin Lan
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Zulin Zhang
- School of Resources and Environmental Engineering, Wuhan University of Technology, Wuhan, China.,The James Hutton Institute, Aberdeen, United Kingdom
| | - Lie Yang
- School of Resources and Environmental Engineering, Wuhan University of Technology, Wuhan, China
| | - Long Qian
- School of Resources and Environmental Engineering, Wuhan University of Technology, Wuhan, China
| | - Ling Xia
- School of Resources and Environmental Engineering, Wuhan University of Technology, Wuhan, China
| | - Shaoxian Song
- School of Resources and Environmental Engineering, Wuhan University of Technology, Wuhan, China
| | - María E Farías
- Laboratorio de Investigaciones Microbiológicas de Lagunas Andinas (LIMLA), Planta Piloto de Procesos Industriales Microbiológicos (PROIMI), Centro Científico Tecnológico (CCT), Consejo Nacional de Investigaciones Científicas y Técnicas, San Miguel de Tucumán, Argentina
| | - Rosa María Torres
- CETMIC- CONICET- CCT La Plata, Comisión de Investigaciones Científicas de la Provincia de Buenos Aires (CICBA), La Plata, Argentina
| | - Li Wu
- School of Resources and Environmental Engineering, Wuhan University of Technology, Wuhan, China
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8
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Abstract
Arid ecosystems cover ∼40% of the Earth's terrestrial surface and store a high proportion of the global nitrogen (N) pool. They are low-productivity, low-biomass, and polyextreme ecosystems, i.e., with (hyper)arid and (hyper)oligotrophic conditions and high surface UV irradiation and evapotranspiration. These polyextreme conditions severely limit the presence of macrofauna and -flora and, particularly, the growth and productivity of plant species. Therefore, it is generally recognized that much of the primary production (including N-input processes) and nutrient biogeochemical cycling (particularly N cycling) in these ecosystems are microbially mediated. Consequently, we present a comprehensive survey of the current state of knowledge of biotic and abiotic N-cycling processes of edaphic (i.e., open soil, biological soil crust, or plant-associated rhizosphere and rhizosheath) and hypo/endolithic refuge niches from drylands in general, including hot, cold, and polar desert ecosystems. We particularly focused on the microbially mediated biological nitrogen fixation, N mineralization, assimilatory and dissimilatory nitrate reduction, and nitrification N-input processes and the denitrification and anaerobic ammonium oxidation (anammox) N-loss processes. We note that the application of modern meta-omics and related methods has generated comprehensive data sets on the abundance, diversity, and ecology of the different N-cycling microbial guilds. However, it is worth mentioning that microbial N-cycling data from important deserts (e.g., Sahara) and quantitative rate data on N transformation processes from various desert niches are lacking or sparse. Filling this knowledge gap is particularly important, as climate change models often lack data on microbial activity and environmental microbial N-cycling communities can be key actors of climate change by producing or consuming nitrous oxide (N2O), a potent greenhouse gas.
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Durán J, Rodríguez A, Fangueiro D, De Los Ríos A. In-situ soil greenhouse gas fluxes under different cryptogamic covers in maritime Antarctica. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 770:144557. [PMID: 33508664 DOI: 10.1016/j.scitotenv.2020.144557] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 11/24/2020] [Accepted: 12/13/2020] [Indexed: 06/12/2023]
Abstract
Soils can influence climate by sequestering or emitting greenhouse gases (GHG) such as carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). We are far from understanding the direct influence of cryptogamic covers on soil GHG fluxes, particularly in areas free of potential anthropogenic confounding factors. We assessed the role of well-developed cryptogamic covers in soil attributes, as well as in the in-situ exchange of GHG between Antarctic soils and the atmosphere during the austral summer. We found lower values of soil organic matter, total organic carbon, and total nitrogen in bare areas than in soils covered by mosses and, particularly, lichens. These differences, together with concomitant decreases and increases in soil temperature and moisture, respectively, resulted in increases in in-situ CO2 emission (i.e. ecosystem respiration) and decreases in CH4 uptake but no significant changes in N2O fluxes. We found consistent linear positive and negative relationships between soil attributes (i.e. soil organic matter, total organic carbon and total nitrogen) and CO2 emissions and CH4 uptake, respectively, and polynomial relationships between these soil attributes and net N2O fluxes. Our results indicate that any increase in the area occupied by cryptogams in terrestrial Antarctic ecosystems (due to increased growing season and increasingly warming conditions) will likely result in parallel increases in soil fertility as well as in an enhanced capacity to emit CO2 and a decreased capacity to uptake CH4. Such changes, unless offset by parallel C uptake processes, would represent a paradigmatic example of a positive climate change feedback. Further, we show that the fate of these terrestrial ecosystems under future climate scenarios, as well as their capacity to exchange GHG with the atmosphere might depend on the relative ability of different aboveground cryptogams to thrive under the new conditions.
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Affiliation(s)
- J Durán
- Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, 3000-456 Coimbra, Portugal.
| | - A Rodríguez
- Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, 3000-456 Coimbra, Portugal
| | - D Fangueiro
- LEAF, Instituto Superior de Agronomia, Universidade de Lisboa, Tapada da Ajuda, 1349-017 Lisboa, Portugal
| | - A De Los Ríos
- Department of Biogeochemistry and Microbial Ecology, National Museum of Natural Sciences (MNCN), CSIC, E-28006 Madrid, Spain
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