气候变化领域集成服务门户(CCPortal): Dark carbon fixation in the Arabian Sea oxygen minimum zone contributes to sedimentary organic carbon (SOM)

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DOI	10.1029/2019GB006282
	Dark carbon fixation in the Arabian Sea oxygen minimum zone contributes to sedimentary organic carbon (SOM)
	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.
发表日期	2019
ISSN	0886-6236
EISSN	1944-9224
起始页码	1715
结束页码	1732
卷号	33 期号:12
英文摘要	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.
英文关键词	Anammox; Carbon cycle; Chemoautotrophy; Organic matter; Oxygen minimum zones; Stable isotopes
语种	英语
scopus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
来源期刊	Global Biogeochemical Cycles
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/129683
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
推荐引用方式 GB/T 7714	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],2019,33(12).
APA	Lengger S.K..,Rush D..,Mayser J.P..,Blewett J..,Schwartz-Narbonne R..,...&Pancost R.D..(2019).Dark carbon fixation in the Arabian Sea oxygen minimum zone contributes to sedimentary organic carbon (SOM).Global Biogeochemical Cycles,33(12).
MLA	Lengger S.K.,et al."Dark carbon fixation in the Arabian Sea oxygen minimum zone contributes to sedimentary organic carbon (SOM)".Global Biogeochemical Cycles 33.12(2019).