1
|
McFarlin JM, Axford Y, Kusch S, Masterson AL, Lasher GE, Osburn MR. Aquatic plant wax hydrogen and carbon isotopes in Greenland lakes record shifts in methane cycling during past Holocene warming. SCIENCE ADVANCES 2023; 9:eadh9704. [PMID: 37774023 PMCID: PMC10541501 DOI: 10.1126/sciadv.adh9704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Accepted: 08/30/2023] [Indexed: 10/01/2023]
Abstract
Predicting changes to methane cycling in Arctic lakes is of global concern in a warming world but records constraining lake methane dynamics with past warming are rare. Here, we demonstrate that the hydrogen isotopic composition (δ2H) of mid-chain waxes derived from aquatic moss clearly decouples from precipitation during past Holocene warmth and instead records incorporation of methane in plant biomass. Trends in δ2Hmoss and δ13Cmoss values point to widespread Middle Holocene (11,700 to 4200 years ago) shifts in lake methane cycling across Greenland during millennia of elevated summer temperatures, heightened productivity, and lowered hypolimnetic oxygen. These data reveal ongoing warming may lead to increases in methane-derived C in many Arctic lakes, including lakes where methane is not a major component of the C cycle today. This work highlights a previously unrecognized mechanism influencing δ2H values of mid-chain wax and draws attention to the unquantified role of common aquatic mosses as a potentially important sink of lake methane across the Arctic.
Collapse
Affiliation(s)
- Jamie M. McFarlin
- Department of Geology and Geophysics, University of Wyoming, Laramie, WY, USA
- Department of Earth and Planetary Sciences, Northwestern University, Evanston, IL, USA
| | - Yarrow Axford
- Department of Earth and Planetary Sciences, Northwestern University, Evanston, IL, USA
| | - Stephanie Kusch
- Institut des Sciences de la Mer, Université du Québec à Rimouski, Rimouski, Canada
| | - Andrew L. Masterson
- Department of Earth and Planetary Sciences, Northwestern University, Evanston, IL, USA
| | - G. Everett Lasher
- Department of Earth and Planetary Sciences, Northwestern University, Evanston, IL, USA
| | - Magdalena R. Osburn
- Department of Earth and Planetary Sciences, Northwestern University, Evanston, IL, USA
| |
Collapse
|
2
|
Peng H, Rong Y, Chen D, Sun R, Huang J, Ding H, Olid C, Yan H. Anthropogenic activity and millennial climate variability affect Holocene mercury deposition of an alpine wetland near the largest mercury mine in China. CHEMOSPHERE 2023; 316:137855. [PMID: 36642145 DOI: 10.1016/j.chemosphere.2023.137855] [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: 11/10/2022] [Revised: 01/09/2023] [Accepted: 01/11/2023] [Indexed: 06/17/2023]
Abstract
Mercury (Hg) is a potentially toxic element that can be transported globally through the atmosphere, once deposited in the environment, has strong bioaccumulation and extreme toxicity in food webs, especially in wetland ecosystems. Anthropogenic Hg emissions have enhanced Hg deposition by 3-5 times since the industrial revolution, and the mining and smelting of Hg ore are important emission sources. However, the dynamics in Hg deposition around the largest Hg mine in China before the industrial revolution and their driving forces remain poorly explored. Here we reconstruct the atmospheric Hg depositional fluxes (named here Hg influx (Hginflux)) during the Holocene using a 450-cm alpine wetland sediment core taken from the Jiulongchi wetland, which is only 65 km to the Wanshan Mercury Mine. Our record shows an abrupt rapid increase in Hg concentration since 2500 cal yr BP, suggesting that Hg mining in southwest China may have started before the establishment of the Qin dynasty. Two major Hginflux peaks were found during the periods 10,000-6000 and 6000 - 3800 cal yr BP, with an increase in Hg deposition by a factor of 4-8. These two peaks are also found in other terrestrial archives from several sites across the Northern Hemisphere. We speculate that critical millennial-scale climate changes, i.e., the Holocene Climatic Optimum (HCO) and the Mid-Holocene Transition (MHT), were the potential triggers of these two Hginflux peaks. This study highlights the importance of climatic variability and local Hg mining in controlling atmospheric Hg deposition during the Holocene.
Collapse
Affiliation(s)
- Haijun Peng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China; CAS Center for Excellence in Quaternary Science and Global Change, Xi'an, 710061, China.
| | - Yimeng Rong
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China; State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Di Chen
- State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ruiyang Sun
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China; State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jie Huang
- Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China
| | - Hanwei Ding
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Carolina Olid
- UB-Geomodels Research Institute, Departament de Dinàmica de la Terra i l'Oceà, Facultat de Ciències de la Terra, Universitat de Barcelona, Barcelona, 08028, Spain
| | - Haiyu Yan
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China
| |
Collapse
|
3
|
van Winden JF, Talbot HM, Reichart G, McNamara NP, Benthien A, Sinninghe Damsté JS. Influence of temperature on the δ 13 C values and distribution of methanotroph-related hopanoids in Sphagnum-dominated peat bogs. GEOBIOLOGY 2020; 18:497-507. [PMID: 32180328 PMCID: PMC7383571 DOI: 10.1111/gbi.12389] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2019] [Revised: 02/08/2020] [Accepted: 02/27/2020] [Indexed: 06/10/2023]
Abstract
Methane emissions from peat bogs are mitigated by methanotrophs, which live in symbiosis with peat moss (e.g. Sphagnum). Here, we investigate the influence of temperature and resultant changes in methane fluxes on Sphagnum and methanotroph-related biomarkers, evaluating their potential as proxies in ancient bogs. A pulse-chase experiment using 13 C-labelled methane in the field clearly showed label uptake in diploptene, a biomarker for methanotrophs, demonstrating in situ methanotrophic activity in Sphagnum under natural conditions. Peat cores containing live Sphagnum were incubated at 5, 10, 15, 20 and 25°C for two months, causing differences in net methane fluxes. The natural δ13 C values of diploptene extracted from Sphagnum showed a strong correlation with temperature and methane production. The δ13 C values ranged from -34‰ at 5°C to -41‰ at 25°C. These results are best explained by enhanced expression of the methanotrophic enzymatic isotope effect at higher methane concentrations. Hence, δ13 C values of diploptene, or its diagenetic products, potentially provide a useful tool to assess methanotrophic activity in past environments. Increased methane fluxes towards Sphagnum did not affect δ13 C values of bulk Sphagnum and its specific marker, the C23 n-alkane. The concentration of methanotroph-specific bacteriohopanepolyols (BHPs), aminobacteriohopanetetrol (aminotetrol, characteristic for type II and to a lesser extent type I methanotrophs) and aminobacteriohopanepentol (aminopentol, a marker for type I methanotrophs) showed a non-linear response to increased methane fluxes, with relatively high abundances at 25°C compared to those at 20°C or below. Aminotetrol was more abundant than aminopentol, in contrast to similar abundances of aminotetrol and aminopentol in fresh Sphagnum. This probably indicates that type II methanotrophs became prevalent under the experimental conditions relative to type I methanotrophs. Even though BHP concentrations may not directly reflect bacterial activity, they may provide insight into the presence of different types of methanotrophs.
Collapse
Affiliation(s)
- Julia F. van Winden
- Department of Earth SciencesFaculty of GeosciencesUtrecht UniversityUtrechtThe Netherlands
| | - Helen M. Talbot
- School of Civil Engineering and GeoscienceNewcastle UniversityNewcastle upon TyneUK
- Present address:
Department of Archaeology (BioArCh)University of YorkYorkUK
| | - Gert‐Jan Reichart
- Department of Earth SciencesFaculty of GeosciencesUtrecht UniversityUtrechtThe Netherlands
- Departments of Marine Microbiology and Biogeochemistry and Ocean SystemsNIOZ Royal Netherlands Institute for Sea Research, and Utrecht UniversityDen BurgThe Netherlands
| | - Niall P. McNamara
- UK Centre for Ecology & HydrologyLancaster Environment CentreLancasterUK
| | - Albert Benthien
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine ResearchBremerhavenGermany
| | - Jaap S. Sinninghe Damsté
- Department of Earth SciencesFaculty of GeosciencesUtrecht UniversityUtrechtThe Netherlands
- Departments of Marine Microbiology and Biogeochemistry and Ocean SystemsNIOZ Royal Netherlands Institute for Sea Research, and Utrecht UniversityDen BurgThe Netherlands
| |
Collapse
|
4
|
Argiriadis E, Martino M, Segnana M, Poto L, Vecchiato M, Battistel D, Gambaro A, Barbante C. Multi-proxy biomarker determination in peat: Optimized extraction and cleanup method for paleoenvironmental application. Microchem J 2020. [DOI: 10.1016/j.microc.2020.104821] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
|
5
|
Response of carbon cycle to drier conditions in the mid-Holocene in central China. Nat Commun 2018; 9:1369. [PMID: 29636471 PMCID: PMC5893629 DOI: 10.1038/s41467-018-03804-w] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2017] [Accepted: 03/14/2018] [Indexed: 11/15/2022] Open
Abstract
The nature and extent to which hydrological changes induced by the Asian summer monsoon affected key biogeochemical processes remain poorly defined. This study explores the relationship between peatland drying and carbon cycling on centennial timescales in central China using lipid biomarkers. The difference between peat n-alkane δ2H and a nearby stalagmite δ18O record reveals that intervals of prominent peatland drying occurred during the mid-Holocene. Synchronous with these drier conditions, leaf wax δ13C values show large negative excursions, with the utilization of CO2 respired from the peatland subsurface for plant photosynthesis being a possible mechanism. Crucially, successive drying events appear to have had a cumulative impact on the susceptibility of peat carbon stores to climate change. Concurrently, bacterially derived hopane δ13C values suggest the occurrence of enhanced methane oxidation during the drier periods. Collectively, these observations expand our understanding of how respiration and degradation of peat are enhanced during drying events. The effect of Asian summer monsoon hydrological changes on key biogeochemical processes remains poorly understood. Here, using a suite of biomarkers, the authors reconstruct palaeohydrological conditions during the Holocene and show that the peatland carbon cycle is strongly sensitive to paleohydrological changes.
Collapse
|
6
|
Wang X, Huang X, Sachse D, Ding W, Xue J. Molecular Paleoclimate Reconstructions over the Last 9 ka from a Peat Sequence in South China. PLoS One 2016; 11:e0160934. [PMID: 27505008 PMCID: PMC4978407 DOI: 10.1371/journal.pone.0160934] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 07/27/2016] [Indexed: 11/24/2022] Open
Abstract
To achieve a better understanding of Holocene climate change in the monsoon regions of China, we investigated the molecular distributions and carbon and hydrogen isotope compositions (δ13C and δD values) of long-chain n-alkanes in a peat core from the Shiwangutian (SWGT) peatland, south China over the last 9 ka. By comparisons with other climate records, we found that the δ13C values of the long-chain n-alkanes can be a proxy for humidity, while the δD values of the long-chain n-alkanes primarily recorded the moisture source δD signal during 9–1.8 ka BP and responded to the dry climate during 1.8–0.3 ka BP. Together with the average chain length (ACL) and the carbon preference index (CPI) data, the climate evolution over last 9 ka in the SWGT peatland can be divided into three stages. During the first stage (9–5 ka BP), the δ13C values were depleted and CPI and Paq values were low, while ACL values were high. They reveal a period of warm and wet climate, which is regarded as the Holocene optimum. The second stage (5–1.8 ka BP) witnessed a shift to relatively cool and dry climate, as indicated by the more positive δ13C values and lower ACL values. During the third stage (1.8–0.3 ka BP), the δ13C, δD, CPI and Paq values showed marked increase and ACL values varied greatly, implying an abrupt change to cold and dry conditions. This climate pattern corresponds to the broad decline in Asian monsoon intensity through the latter part of the Holocene. Our results do not support a later Holocene optimum in south China as suggested by previous studies.
Collapse
Affiliation(s)
- Xinxin Wang
- Laboratory of Critical Zone Evolution, School of Earth Sciences, China University of Geosciences, Wuhan, China
| | - Xianyu Huang
- Laboratory of Critical Zone Evolution, School of Earth Sciences, China University of Geosciences, Wuhan, China
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, China
- * E-mail:
| | - Dirk Sachse
- Institute of Earth and Environmental Science, University of Potsdam, Potsdam, Germany
- Organic Surface Geochemistry Lab, Section 5.1 Geomorphology, GFZ German Research Centre for Geosciences, Potsdam, Germany
| | - Weihua Ding
- Laboratory of Critical Zone Evolution, School of Earth Sciences, China University of Geosciences, Wuhan, China
| | - Jiantao Xue
- Laboratory of Critical Zone Evolution, School of Earth Sciences, China University of Geosciences, Wuhan, China
| |
Collapse
|
7
|
Xu H, Lan J, Sheng E, Liu Y, Liu B, Yu K, Ye Y, Cheng P, Qiang X, Lu F, Wang X. Tropical/Subtropical Peatland Development and Global CH4 during the Last Glaciation. Sci Rep 2016; 6:30431. [PMID: 27465566 PMCID: PMC4964359 DOI: 10.1038/srep30431] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 07/01/2016] [Indexed: 11/09/2022] Open
Abstract
Knowledge of peatland development over the tropical/subtropical zone during the last glaciation is critical for understanding the glacial global methane cycle. Here we present a well-dated ‘peat deposit-lake sediment’ alternate sequence at Tengchong, southwestern China, and discuss the peatland development and its linkage to the global glacial methane cycle. Peat layers were formed during the cold Marine Isotope Stage (MIS)-2 and -4, whereas lake sediments coincided with the relatively warm MIS-3, which is possibly related to the orbital/suborbital variations in both temperature and Asian summer monsoon intensity. The Tengchong peatland formation pattern is broadly synchronous with those over subtropical southern China and other tropical/subtropical areas, but it is clearly in contrast to those over the mid-high Northern Hemisphere. The results of this work suggest that the shifts of peatland development between the tropical/subtropical zone and mid-high Northern Hemisphere may have played important roles in the glacial/interglacial global atmospheric CH4 cycles.
Collapse
Affiliation(s)
- Hai Xu
- State key Laboratory of Loess and Quaternary Geology, institute of Earth Environment, Chinese Academy of Sciences. Xi'an, China.,Department of Environment Science and Technology, School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, China
| | - Jianghu Lan
- State key Laboratory of Loess and Quaternary Geology, institute of Earth Environment, Chinese Academy of Sciences. Xi'an, China
| | - Enguo Sheng
- State key Laboratory of Loess and Quaternary Geology, institute of Earth Environment, Chinese Academy of Sciences. Xi'an, China
| | - Yong Liu
- College of Tourism and Geographical Sciences, Yunnan Normal University, Kunming, China
| | - Bin Liu
- State key Laboratory of Loess and Quaternary Geology, institute of Earth Environment, Chinese Academy of Sciences. Xi'an, China
| | - Keke Yu
- State key Laboratory of Loess and Quaternary Geology, institute of Earth Environment, Chinese Academy of Sciences. Xi'an, China.,Graduate university of Chinese Academy of Sciences. Beijing, China
| | - Yuanda Ye
- State key Laboratory of Loess and Quaternary Geology, institute of Earth Environment, Chinese Academy of Sciences. Xi'an, China.,Graduate university of Chinese Academy of Sciences. Beijing, China
| | - Peng Cheng
- State key Laboratory of Loess and Quaternary Geology, institute of Earth Environment, Chinese Academy of Sciences. Xi'an, China
| | - Xiaoke Qiang
- State key Laboratory of Loess and Quaternary Geology, institute of Earth Environment, Chinese Academy of Sciences. Xi'an, China
| | - Fengyan Lu
- State key Laboratory of Loess and Quaternary Geology, institute of Earth Environment, Chinese Academy of Sciences. Xi'an, China
| | - Xulong Wang
- State key Laboratory of Loess and Quaternary Geology, institute of Earth Environment, Chinese Academy of Sciences. Xi'an, China
| |
Collapse
|
8
|
Oviedo JP, KC S, Lu N, Wang J, Cho K, Wallace RM, Kim MJ. In situ TEM characterization of shear-stress-induced interlayer sliding in the cross section view of molybdenum disulfide. ACS NANO 2015; 9:1543-1551. [PMID: 25494557 DOI: 10.1021/nn506052d] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The experimental study of interlayer sliding at the nanoscale in layered solids has been limited thus far by the incapability of mechanical and imaging probes to simultaneously access sliding interfaces and overcome through mechanical stimulus the van der Waals and Coulombic interactions holding the layers in place. For this purpose, straightforward methods were developed to achieve interlayer sliding in molybdenum disulfide (MoS2) while under observation within a transmission electron microscope. A method to manipulate, tear, and slide free-standing atomic layers of MoS2 is demonstrated by electrostatically coupling it to an oxidized tungsten probe attached to a micromanipulator at a bias above ±7 V. A first-principles model of a MoS2 bilayer polarized by a normal electric field of 5 V/nm, emanating from the tip, demonstrates the appearance of a periodic negative sliding potential energy barrier when the layers slide into the out-of-registry stacking configuration, hinting at electrostatic gating as a means of modifying the interlayer tribology to facilitate shear exfoliation. A method to shear focused ion beam prepared MoS2 cross section samples using a nanoindenter force sensor is also demonstrated, allowing both the observation and force measurement of its interlayer dynamics during shear-induced sliding. From this experiment, the zero normal load shear strength of MoS2 can be directly obtained: 25.3 ± 0.6 MPa. These capabilities enable the site-specific mechanical testing of dry lubricant-based nanoelectromechanical devices and can lead to a better understanding of the atomic mechanisms from which the interlayer tribology of layered materials originates.
Collapse
Affiliation(s)
- Juan Pablo Oviedo
- Materials Science and Engineering Department, The University of Texas at Dallas , 800 West Campbell Road, Richardson, Texas 75080, United States
| | | | | | | | | | | | | |
Collapse
|