Partitioning Effects during Terminal Carbon and Electron Flow in Sediments of a Low-Salinity Meltwater Pond near Bratina Island, McMurdo Ice Shelf, Antarctica
A study of anaerobic sediments below cyanobacterial mats of a low-salinity meltwater pond called Orange Pond on the McMurdo Ice Shelf at temperatures simulating those in the summer season (<5°C) revealed that both sulfate reduction and methane production were important terminal anaerobic processe...
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ftpubmed:oai:pubmedcentral.nih.gov:91748 2023-05-15T13:55:23+02:00 Partitioning Effects during Terminal Carbon and Electron Flow in Sediments of a Low-Salinity Meltwater Pond near Bratina Island, McMurdo Ice Shelf, Antarctica Mountfort, Douglas O. Kaspar, Heinrich F. Downes, Malcolm Asher, Rodney A. 1999-12 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC91748 http://www.ncbi.nlm.nih.gov/pubmed/10584008 en eng American Society for Microbiology http://www.ncbi.nlm.nih.gov/pmc/articles/PMC91748 http://www.ncbi.nlm.nih.gov/pubmed/10584008 Copyright © 1999, American Society for Microbiology General Microbial Ecology Text 1999 ftpubmed 2013-08-29T09:19:34Z A study of anaerobic sediments below cyanobacterial mats of a low-salinity meltwater pond called Orange Pond on the McMurdo Ice Shelf at temperatures simulating those in the summer season (<5°C) revealed that both sulfate reduction and methane production were important terminal anaerobic processes. Addition of [2-14C]acetate to sediment samples resulted in the passage of label mainly to CO2. Acetate addition (0 to 27 mM) had little effect on methanogenesis (a 1.1-fold increase), and while the rate of acetate dissimilation was greater than the rate of methane production (6.4 nmol cm−3 h−1 compared to 2.5 to 6 nmol cm−3 h−1), the portion of methane production attributed to acetate cleavage was <2%. Substantial increases in the methane production rate were observed with H2 (2.4-fold), and H2 uptake was totally accounted for by methane production under physiological conditions. Formate also stimulated methane production (twofold), presumably through H2 release mediated through hydrogen lyase. Addition of sulfate up to 50-fold the natural levels in the sediment (interstitial concentration, ∼0.3 mM) did not substantially inhibit methanogenesis, but the process was inhibited by 50-fold chloride (36 mM). No net rate of methane oxidation was observed when sediments were incubated anaerobically, and denitrification rates were substantially lower than rates for sulfate reduction and methanogenesis. The results indicate that carbon flow from acetate is coupled mainly to sulfate reduction and that methane is largely generated from H2 and CO2 where chloride, but not sulfate, has a modulating role. Rates of methanogenesis at in situ temperatures were four- to fivefold less than maximal rates found at 20°C. Text Antarc* Antarctica Bratina Island Ice Shelf McMurdo Ice Shelf PubMed Central (PMC) Bratina Island ENVELOPE(165.533,165.533,-78.017,-78.017) McMurdo Ice Shelf ENVELOPE(166.500,166.500,-78.000,-78.000) |
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PubMed Central (PMC) |
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ftpubmed |
language |
English |
topic |
General Microbial Ecology |
spellingShingle |
General Microbial Ecology Mountfort, Douglas O. Kaspar, Heinrich F. Downes, Malcolm Asher, Rodney A. Partitioning Effects during Terminal Carbon and Electron Flow in Sediments of a Low-Salinity Meltwater Pond near Bratina Island, McMurdo Ice Shelf, Antarctica |
topic_facet |
General Microbial Ecology |
description |
A study of anaerobic sediments below cyanobacterial mats of a low-salinity meltwater pond called Orange Pond on the McMurdo Ice Shelf at temperatures simulating those in the summer season (<5°C) revealed that both sulfate reduction and methane production were important terminal anaerobic processes. Addition of [2-14C]acetate to sediment samples resulted in the passage of label mainly to CO2. Acetate addition (0 to 27 mM) had little effect on methanogenesis (a 1.1-fold increase), and while the rate of acetate dissimilation was greater than the rate of methane production (6.4 nmol cm−3 h−1 compared to 2.5 to 6 nmol cm−3 h−1), the portion of methane production attributed to acetate cleavage was <2%. Substantial increases in the methane production rate were observed with H2 (2.4-fold), and H2 uptake was totally accounted for by methane production under physiological conditions. Formate also stimulated methane production (twofold), presumably through H2 release mediated through hydrogen lyase. Addition of sulfate up to 50-fold the natural levels in the sediment (interstitial concentration, ∼0.3 mM) did not substantially inhibit methanogenesis, but the process was inhibited by 50-fold chloride (36 mM). No net rate of methane oxidation was observed when sediments were incubated anaerobically, and denitrification rates were substantially lower than rates for sulfate reduction and methanogenesis. The results indicate that carbon flow from acetate is coupled mainly to sulfate reduction and that methane is largely generated from H2 and CO2 where chloride, but not sulfate, has a modulating role. Rates of methanogenesis at in situ temperatures were four- to fivefold less than maximal rates found at 20°C. |
format |
Text |
author |
Mountfort, Douglas O. Kaspar, Heinrich F. Downes, Malcolm Asher, Rodney A. |
author_facet |
Mountfort, Douglas O. Kaspar, Heinrich F. Downes, Malcolm Asher, Rodney A. |
author_sort |
Mountfort, Douglas O. |
title |
Partitioning Effects during Terminal Carbon and Electron Flow in Sediments of a Low-Salinity Meltwater Pond near Bratina Island, McMurdo Ice Shelf, Antarctica |
title_short |
Partitioning Effects during Terminal Carbon and Electron Flow in Sediments of a Low-Salinity Meltwater Pond near Bratina Island, McMurdo Ice Shelf, Antarctica |
title_full |
Partitioning Effects during Terminal Carbon and Electron Flow in Sediments of a Low-Salinity Meltwater Pond near Bratina Island, McMurdo Ice Shelf, Antarctica |
title_fullStr |
Partitioning Effects during Terminal Carbon and Electron Flow in Sediments of a Low-Salinity Meltwater Pond near Bratina Island, McMurdo Ice Shelf, Antarctica |
title_full_unstemmed |
Partitioning Effects during Terminal Carbon and Electron Flow in Sediments of a Low-Salinity Meltwater Pond near Bratina Island, McMurdo Ice Shelf, Antarctica |
title_sort |
partitioning effects during terminal carbon and electron flow in sediments of a low-salinity meltwater pond near bratina island, mcmurdo ice shelf, antarctica |
publisher |
American Society for Microbiology |
publishDate |
1999 |
url |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC91748 http://www.ncbi.nlm.nih.gov/pubmed/10584008 |
long_lat |
ENVELOPE(165.533,165.533,-78.017,-78.017) ENVELOPE(166.500,166.500,-78.000,-78.000) |
geographic |
Bratina Island McMurdo Ice Shelf |
geographic_facet |
Bratina Island McMurdo Ice Shelf |
genre |
Antarc* Antarctica Bratina Island Ice Shelf McMurdo Ice Shelf |
genre_facet |
Antarc* Antarctica Bratina Island Ice Shelf McMurdo Ice Shelf |
op_relation |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC91748 http://www.ncbi.nlm.nih.gov/pubmed/10584008 |
op_rights |
Copyright © 1999, American Society for Microbiology |
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