The effects of organic matter and anaerobic oxidation of methane on the microbial sulfate reduction in cold seeps

Cold seep sediments are dominated by intensive microbial sulfate reduction coupled to anaerobic oxidation of methane. However, the contribution proportion between this process and the role of organic matter has remained enigmatic. Here, pore water data combined with PROFILE model, fluxes of sulfate...

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Main Authors: Tiantian Sun, Daidai Wu, Nengyou Wu, Ping Yin
Format: Article
Language:English
Published: Frontiers Media S.A. 2023-03-01
Series:Frontiers in Marine Science
Subjects:
Online Access:https://www.frontiersin.org/articles/10.3389/fmars.2023.1111133/full
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author Tiantian Sun
Tiantian Sun
Daidai Wu
Nengyou Wu
Nengyou Wu
Ping Yin
Ping Yin
author_facet Tiantian Sun
Tiantian Sun
Daidai Wu
Nengyou Wu
Nengyou Wu
Ping Yin
Ping Yin
author_sort Tiantian Sun
collection DOAJ
description Cold seep sediments are dominated by intensive microbial sulfate reduction coupled to anaerobic oxidation of methane. However, the contribution proportion between this process and the role of organic matter has remained enigmatic. Here, pore water data combined with PROFILE model, fluxes of sulfate and methane concentration calculated from Fick's first law, and δ34SSO4 and δ18OSO4 of pore water sulfate were studied to reconstruct co-occurring microbial organoclastic sulfate reduction and anaerobic oxidation of methane coupled with sulfate reduction in methane seep sediments collected from South China Sea. The sulfate concentration profiles of C9 and C14 in Qiongdongnan Basin generally show quasilinear depletion with depth. Reaction-transport modeling provided close fits to concentration data. δ18OSO4 and δ34SSO4 increase fastest with sediment depth above 400 cmbsf and slowest below that depth. The values of methane flux are always lower than those of total sulfate reduction of sulfate diffusive flux at GC-10, GC-9, GC-11 and HD319 sites in Taixinan Basin. Besides, positions of sulfate methane transition zone in all study sites are approximately ~400 to 800 centimeters below seafloor. These results showed that microbial sulfate reduction in sediments is mainly controlled by intense anaerobic oxidation of methane, but there is a certain relationship with organic matter metabolism process. This emphasizes that traditional redox order of bacterial respiration is highly simplified, where, in sediments such as these seeps, all of these microbial sulfate reduction processes can occur together with complex couplings between them.
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spelling doaj.art-295be98f964342e588f476161c13b0662023-03-15T11:51:14ZengFrontiers Media S.A.Frontiers in Marine Science2296-77452023-03-011010.3389/fmars.2023.11111331111133The effects of organic matter and anaerobic oxidation of methane on the microbial sulfate reduction in cold seepsTiantian Sun0Tiantian Sun1Daidai Wu2Nengyou Wu3Nengyou Wu4Ping Yin5Ping Yin6Qingdao Institute of Marine Geology, China Geological Survey, Ministry of Natural Resources, Qingdao, ChinaLaboratory for Marine Geology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, ChinaGuangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou, ChinaQingdao Institute of Marine Geology, China Geological Survey, Ministry of Natural Resources, Qingdao, ChinaLaboratory for Marine Geology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, ChinaQingdao Institute of Marine Geology, China Geological Survey, Ministry of Natural Resources, Qingdao, ChinaLaboratory for Marine Geology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, ChinaCold seep sediments are dominated by intensive microbial sulfate reduction coupled to anaerobic oxidation of methane. However, the contribution proportion between this process and the role of organic matter has remained enigmatic. Here, pore water data combined with PROFILE model, fluxes of sulfate and methane concentration calculated from Fick's first law, and δ34SSO4 and δ18OSO4 of pore water sulfate were studied to reconstruct co-occurring microbial organoclastic sulfate reduction and anaerobic oxidation of methane coupled with sulfate reduction in methane seep sediments collected from South China Sea. The sulfate concentration profiles of C9 and C14 in Qiongdongnan Basin generally show quasilinear depletion with depth. Reaction-transport modeling provided close fits to concentration data. δ18OSO4 and δ34SSO4 increase fastest with sediment depth above 400 cmbsf and slowest below that depth. The values of methane flux are always lower than those of total sulfate reduction of sulfate diffusive flux at GC-10, GC-9, GC-11 and HD319 sites in Taixinan Basin. Besides, positions of sulfate methane transition zone in all study sites are approximately ~400 to 800 centimeters below seafloor. These results showed that microbial sulfate reduction in sediments is mainly controlled by intense anaerobic oxidation of methane, but there is a certain relationship with organic matter metabolism process. This emphasizes that traditional redox order of bacterial respiration is highly simplified, where, in sediments such as these seeps, all of these microbial sulfate reduction processes can occur together with complex couplings between them.https://www.frontiersin.org/articles/10.3389/fmars.2023.1111133/fullmethane seepageanaerobic oxidation of methanemicrobial sulfate reductionOrganoclastic Sulfate ReductionQiongdongnan BasinTaixinan Basin
spellingShingle Tiantian Sun
Tiantian Sun
Daidai Wu
Nengyou Wu
Nengyou Wu
Ping Yin
Ping Yin
The effects of organic matter and anaerobic oxidation of methane on the microbial sulfate reduction in cold seeps
Frontiers in Marine Science
methane seepage
anaerobic oxidation of methane
microbial sulfate reduction
Organoclastic Sulfate Reduction
Qiongdongnan Basin
Taixinan Basin
title The effects of organic matter and anaerobic oxidation of methane on the microbial sulfate reduction in cold seeps
title_full The effects of organic matter and anaerobic oxidation of methane on the microbial sulfate reduction in cold seeps
title_fullStr The effects of organic matter and anaerobic oxidation of methane on the microbial sulfate reduction in cold seeps
title_full_unstemmed The effects of organic matter and anaerobic oxidation of methane on the microbial sulfate reduction in cold seeps
title_short The effects of organic matter and anaerobic oxidation of methane on the microbial sulfate reduction in cold seeps
title_sort effects of organic matter and anaerobic oxidation of methane on the microbial sulfate reduction in cold seeps
topic methane seepage
anaerobic oxidation of methane
microbial sulfate reduction
Organoclastic Sulfate Reduction
Qiongdongnan Basin
Taixinan Basin
url https://www.frontiersin.org/articles/10.3389/fmars.2023.1111133/full
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