globalchange  > 气候变化与战略
DOI: 10.1029/2019GB006282
论文题名:
Dark carbon fixation in the Arabian Sea oxygen minimum zone contributes to sedimentary organic carbon (SOM)
作者: Lengger S.K.; Rush D.; Mayser J.P.; Blewett J.; Schwartz-Narbonne R.; Talbot H.M.; Middelburg J.J.; Jetten M.S.M.; Schouten S.; Sinninghe Damsté J.S.; Pancost R.D.
刊名: Global Biogeochemical Cycles
ISSN: 0886-6236
EISSN: 1944-9224
出版年: 2019
卷: 33, 期:12
语种: 英语
英文关键词: ammonia ; anoxic conditions ; biochemical oxygen demand ; carbon cycle ; carbon fixation ; chemoautotrophy ; detritus ; organic matter ; oxidation ; oxygen minimum layer ; stable isotope ; Arabian Sea ; Indian Ocean
学科: Anammox ; Carbon cycle ; Chemoautotrophy ; Organic matter ; Oxygen minimum zones ; Stable isotopes
中文摘要: In response to rising CO2 concentrations and increasing global sea surface temperatures, oxygen minimum zones (OMZ), or “dead zones”, are expected to expand. OMZs are fueled by high primary productivity, resulting in enhanced biological oxygen demand at depth, subsequent oxygen depletion, and attenuation of remineralization. This results in the deposition of organic carbon-rich sediments. Carbon drawdown is estimated by biogeochemical models; however, a major process is ignored: carbon fixation in the mid- and lower water column. Here, we show that chemoautotrophic carbon fixation is important in the Arabian Sea OMZ; and manifests in a 13C-depleted signature of sedimentary organic carbon. We determined the δ13C values of Corg deposited in close spatial proximity but over a steep bottom-water oxygen gradient, and the δ13C composition of biomarkers of chemoautotrophic bacteria capable of anaerobic ammonia oxidation (anammox). Isotope mixing models show that detritus from anammox bacteria or other chemoautotrophs likely forms a substantial part of the organic matter deposited within the Arabian Sea OMZ (~17%), implying that the contribution of chemoautotrophs to settling organic matter is exported to the sediment. This has implications for the evaluation of past, and future, OMZs: biogeochemical models that operate on the assumption that all sinking organic matter is photosynthetically derived, without new addition of carbon, could significantly underestimate the extent of remineralization. Oxygen demand in oxygen minimum zones could thus be higher than projections suggest, leading to a more intense expansion of OMZs than expected. ©2019. American Geophysical Union. All Rights Reserved.
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/160078
Appears in Collections:气候变化与战略

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作者单位: Biogeochemistry Research Centre, School of Geography, Earth and Environmental Science, University of Plymouth, Plymouth, United Kingdom; Organic Geochemistry Unit, School of Chemistry, University of Bristol, Bristol, United Kingdom; NIOZ Royal Netherlands Institute for Sea Research, Dept. of Marine Microbiology and Biogeochemistry, and Utrecht University, Texel, Netherlands; School of Natural and Environmental Sciences, Newcastle University, Newcastle-upon-Tyne, United Kingdom; Now at BioArCh, Environment Building, University of York, Heslington, United Kingdom; Department of Earth Sciences, Faculty of Geosciences, Utrecht University, Utrecht, Netherlands; Department of Microbiology, IWWR, Radboud University Nijmegen, Nijmegen, Netherlands

Recommended Citation:
Lengger S.K.,Rush D.,Mayser J.P.,et al. Dark carbon fixation in the Arabian Sea oxygen minimum zone contributes to sedimentary organic carbon (SOM)[J]. Global Biogeochemical Cycles,2019-01-01,33(12)
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