Prominent bacterial heterotrophy and sources of 13 C-depleted fatty acids to the interior Canada Basin
In recent decades, the Canada Basin of the Arctic Ocean has experienced rapidly decreasing summer sea ice coverage and freshening of surface waters. It is unclear how these changes translate to deeper waters, particularly as our baseline understanding of organic carbon cycling in the deep basin is q...
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ftdoajarticles:oai:doaj.org/article:25f34a783b2345029e9d7d83dd996ee9 2023-05-15T15:14:15+02:00 Prominent bacterial heterotrophy and sources of 13 C-depleted fatty acids to the interior Canada Basin S. R. Shah D. R. Griffith V. Galy A. P. McNichol T. I. Eglinton 2013-11-01T00:00:00Z https://doi.org/10.5194/bg-10-7065-2013 https://doaj.org/article/25f34a783b2345029e9d7d83dd996ee9 EN eng Copernicus Publications http://www.biogeosciences.net/10/7065/2013/bg-10-7065-2013.pdf https://doaj.org/toc/1726-4170 https://doaj.org/toc/1726-4189 1726-4170 1726-4189 doi:10.5194/bg-10-7065-2013 https://doaj.org/article/25f34a783b2345029e9d7d83dd996ee9 Biogeosciences, Vol 10, Iss 11, Pp 7065-7080 (2013) Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 article 2013 ftdoajarticles https://doi.org/10.5194/bg-10-7065-2013 2022-12-31T06:26:32Z In recent decades, the Canada Basin of the Arctic Ocean has experienced rapidly decreasing summer sea ice coverage and freshening of surface waters. It is unclear how these changes translate to deeper waters, particularly as our baseline understanding of organic carbon cycling in the deep basin is quite limited. In this study, we describe full-depth profiles of the abundance, distribution and carbon isotopic composition of fatty acids from suspended particulate matter at a seasonally ice-free station and a semi-permanently ice-covered station. Fatty acids, along with suspended particulate organic carbon (POC), are more concentrated and 13 C-enriched under ice cover than in ice-free waters. But this influence, apparent at 50 m depth, does not propagate downward below 150 m depth, likely due to the weak biological pump in the central Canada Basin. Branched fatty acids have δ 13 C values that are similar to suspended POC at all depths and are more 13 C-enriched than even-numbered saturated fatty acids at depths above 3000 m. These are likely to be produced in situ by heterotrophic bacteria incorporating organic carbon that is isotopically similar to total suspended POC. Below surface waters, there is also the suggestion of a source of saturated even-numbered fatty acids which could represent contributions from laterally advected organic carbon and/or from chemoautotrophic bacteria. At 3000 m depth and below, a greater relative abundance of long-chain (C 20–24 ), branched and unsaturated fatty acids is consistent with a stronger influence of re-suspended sedimentary organic carbon. At these deep depths, two individual fatty acids (C 12 and iso-C 17 ) are significantly depleted in 13 C, allowing for the possibility that methane oxidizing bacteria contribute fatty acids, either directly to suspended particulate matter or to shallow sediments that are subsequently mobilized and incorporated into suspended particulate matter within the deep basin. Article in Journal/Newspaper Arctic Arctic Ocean canada basin Sea ice Directory of Open Access Journals: DOAJ Articles Arctic Arctic Ocean Canada Biogeosciences 10 11 7065 7080 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 |
spellingShingle |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 S. R. Shah D. R. Griffith V. Galy A. P. McNichol T. I. Eglinton Prominent bacterial heterotrophy and sources of 13 C-depleted fatty acids to the interior Canada Basin |
topic_facet |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 |
description |
In recent decades, the Canada Basin of the Arctic Ocean has experienced rapidly decreasing summer sea ice coverage and freshening of surface waters. It is unclear how these changes translate to deeper waters, particularly as our baseline understanding of organic carbon cycling in the deep basin is quite limited. In this study, we describe full-depth profiles of the abundance, distribution and carbon isotopic composition of fatty acids from suspended particulate matter at a seasonally ice-free station and a semi-permanently ice-covered station. Fatty acids, along with suspended particulate organic carbon (POC), are more concentrated and 13 C-enriched under ice cover than in ice-free waters. But this influence, apparent at 50 m depth, does not propagate downward below 150 m depth, likely due to the weak biological pump in the central Canada Basin. Branched fatty acids have δ 13 C values that are similar to suspended POC at all depths and are more 13 C-enriched than even-numbered saturated fatty acids at depths above 3000 m. These are likely to be produced in situ by heterotrophic bacteria incorporating organic carbon that is isotopically similar to total suspended POC. Below surface waters, there is also the suggestion of a source of saturated even-numbered fatty acids which could represent contributions from laterally advected organic carbon and/or from chemoautotrophic bacteria. At 3000 m depth and below, a greater relative abundance of long-chain (C 20–24 ), branched and unsaturated fatty acids is consistent with a stronger influence of re-suspended sedimentary organic carbon. At these deep depths, two individual fatty acids (C 12 and iso-C 17 ) are significantly depleted in 13 C, allowing for the possibility that methane oxidizing bacteria contribute fatty acids, either directly to suspended particulate matter or to shallow sediments that are subsequently mobilized and incorporated into suspended particulate matter within the deep basin. |
format |
Article in Journal/Newspaper |
author |
S. R. Shah D. R. Griffith V. Galy A. P. McNichol T. I. Eglinton |
author_facet |
S. R. Shah D. R. Griffith V. Galy A. P. McNichol T. I. Eglinton |
author_sort |
S. R. Shah |
title |
Prominent bacterial heterotrophy and sources of 13 C-depleted fatty acids to the interior Canada Basin |
title_short |
Prominent bacterial heterotrophy and sources of 13 C-depleted fatty acids to the interior Canada Basin |
title_full |
Prominent bacterial heterotrophy and sources of 13 C-depleted fatty acids to the interior Canada Basin |
title_fullStr |
Prominent bacterial heterotrophy and sources of 13 C-depleted fatty acids to the interior Canada Basin |
title_full_unstemmed |
Prominent bacterial heterotrophy and sources of 13 C-depleted fatty acids to the interior Canada Basin |
title_sort |
prominent bacterial heterotrophy and sources of 13 c-depleted fatty acids to the interior canada basin |
publisher |
Copernicus Publications |
publishDate |
2013 |
url |
https://doi.org/10.5194/bg-10-7065-2013 https://doaj.org/article/25f34a783b2345029e9d7d83dd996ee9 |
geographic |
Arctic Arctic Ocean Canada |
geographic_facet |
Arctic Arctic Ocean Canada |
genre |
Arctic Arctic Ocean canada basin Sea ice |
genre_facet |
Arctic Arctic Ocean canada basin Sea ice |
op_source |
Biogeosciences, Vol 10, Iss 11, Pp 7065-7080 (2013) |
op_relation |
http://www.biogeosciences.net/10/7065/2013/bg-10-7065-2013.pdf https://doaj.org/toc/1726-4170 https://doaj.org/toc/1726-4189 1726-4170 1726-4189 doi:10.5194/bg-10-7065-2013 https://doaj.org/article/25f34a783b2345029e9d7d83dd996ee9 |
op_doi |
https://doi.org/10.5194/bg-10-7065-2013 |
container_title |
Biogeosciences |
container_volume |
10 |
container_issue |
11 |
container_start_page |
7065 |
op_container_end_page |
7080 |
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1766344718610857984 |