Strong contribution of diatom resting spores to deep sea carbon export fluxes in the naturally iron fertilized waters downstream of South Georgia
Biogeochemical and diatom export fluxes are presented from two bathypelagic sediment trap deployments in the Antarctic Zone of the Southern Ocean. One of the sediment traps was deployed in very productive, naturally iron-fertilized waters downstream of South Georgia (P3, 2000 m) and compared to a de...
Published in: | Deep Sea Research Part I: Oceanographic Research Papers |
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Online Access: | https://epic.awi.de/id/eprint/41042/ https://epic.awi.de/id/eprint/41042/1/Rembauville_et_al_2016c_Deep_Sea_Research_I.pdf https://hdl.handle.net/10013/epic.48001 https://hdl.handle.net/10013/epic.48001.d001 |
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ftawi:oai:epic.awi.de:41042 2023-05-15T13:40:27+02:00 Strong contribution of diatom resting spores to deep sea carbon export fluxes in the naturally iron fertilized waters downstream of South Georgia Rembauville, M Manno, C Tarling, G. A. Blain, S. Salter, I 2016-09 application/pdf https://epic.awi.de/id/eprint/41042/ https://epic.awi.de/id/eprint/41042/1/Rembauville_et_al_2016c_Deep_Sea_Research_I.pdf https://hdl.handle.net/10013/epic.48001 https://hdl.handle.net/10013/epic.48001.d001 unknown PERGAMON-ELSEVIER SCIENCE LTD https://epic.awi.de/id/eprint/41042/1/Rembauville_et_al_2016c_Deep_Sea_Research_I.pdf https://hdl.handle.net/10013/epic.48001.d001 Rembauville, M. , Manno, C. , Tarling, G. A. , Blain, S. and Salter, I. orcid:0000-0002-4513-0314 (2016) Strong contribution of diatom resting spores to deep sea carbon export fluxes in the naturally iron fertilized waters downstream of South Georgia , Deep-Sea Research Part I-Oceanographic Research Papers, 115 , pp. 22-35 . doi:10.1016/j.dsr.2016.05.002 <https://doi.org/10.1016/j.dsr.2016.05.002> , hdl:10013/epic.48001 EPIC3Deep-Sea Research Part I-Oceanographic Research Papers, PERGAMON-ELSEVIER SCIENCE LTD, 115, pp. 22-35, ISSN: 0967-0637 Article isiRev 2016 ftawi https://doi.org/10.1016/j.dsr.2016.05.002 2021-12-24T15:41:37Z Biogeochemical and diatom export fluxes are presented from two bathypelagic sediment trap deployments in the Antarctic Zone of the Southern Ocean. One of the sediment traps was deployed in very productive, naturally iron-fertilized waters downstream of South Georgia (P3, 2000 m) and compared to a deployment in moderately productive waters upstream of the island system (P2, 1500 m). At both sites significant diatom export events occurred in spring (November) and contained mostly empty cells that were associated with low particulate organic carbon (POC) fluxes. A summer export pulse occurred one month later at P2 (end February/March) compared to P3 (end January). Diatom fluxes at P3 were one order of magnitude higher than at P2, a difference mainly attributed to the short and intense export of resting spores from Chaetoceros Hyalochaete and Thalassiosira antarctica species. Aside from these resting spores, diatom export assemblages at both sites were dominated by empty Fragilariopsis kerguelensis frustules. The fraction of diatoms exported as empty frustules was considerably lower at P3 (52%) than P2 (91%). This difference was related to the flux of intact diatom resting spores at P3 and may partially explain the lower Si:C export stoichiometry observed at P3 (1.1) compared to P2 (1.5). Through the enumeration of full diatom frustules and subsequent biomass calculations we estimate that diatom resting spores account for 42% of annual POC flux in the productive waters downstream of South Georgia. At both sites the contribution of diatom vegetative stages to POC fluxes was considerably lower (<5%). From these analyses we conclude that resting spore export contributes towards the slightly higher bathypelagic (POC) flux at P3 (40.6 mmol m−2 y−1) compared to P2 (26.4 mmol m−2 y−1). We compared our sediment trap records with previously published diatom assemblage data from the mixed layer and surface sediments (3760 m) around South Georgia. The relative proportion of diatom resting spores within diatom assemblages increases as a function of depth and is explained by selective preservation of their robust frustules. Our study highlights the significance of diatom resting spore export as a carbon vector out of the mixed layer. Furthermore, the contribution or resting spores to POC flux in the bathypelagic ocean and sediments suggests they play a particularly important role in sequestering biologically fixed CO2 over climatically relevant timescales. Article in Journal/Newspaper Antarc* Antarctic Antarctica Southern Ocean Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) Antarctic Southern Ocean The Antarctic Deep Sea Research Part I: Oceanographic Research Papers 115 22 35 |
institution |
Open Polar |
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Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) |
op_collection_id |
ftawi |
language |
unknown |
description |
Biogeochemical and diatom export fluxes are presented from two bathypelagic sediment trap deployments in the Antarctic Zone of the Southern Ocean. One of the sediment traps was deployed in very productive, naturally iron-fertilized waters downstream of South Georgia (P3, 2000 m) and compared to a deployment in moderately productive waters upstream of the island system (P2, 1500 m). At both sites significant diatom export events occurred in spring (November) and contained mostly empty cells that were associated with low particulate organic carbon (POC) fluxes. A summer export pulse occurred one month later at P2 (end February/March) compared to P3 (end January). Diatom fluxes at P3 were one order of magnitude higher than at P2, a difference mainly attributed to the short and intense export of resting spores from Chaetoceros Hyalochaete and Thalassiosira antarctica species. Aside from these resting spores, diatom export assemblages at both sites were dominated by empty Fragilariopsis kerguelensis frustules. The fraction of diatoms exported as empty frustules was considerably lower at P3 (52%) than P2 (91%). This difference was related to the flux of intact diatom resting spores at P3 and may partially explain the lower Si:C export stoichiometry observed at P3 (1.1) compared to P2 (1.5). Through the enumeration of full diatom frustules and subsequent biomass calculations we estimate that diatom resting spores account for 42% of annual POC flux in the productive waters downstream of South Georgia. At both sites the contribution of diatom vegetative stages to POC fluxes was considerably lower (<5%). From these analyses we conclude that resting spore export contributes towards the slightly higher bathypelagic (POC) flux at P3 (40.6 mmol m−2 y−1) compared to P2 (26.4 mmol m−2 y−1). We compared our sediment trap records with previously published diatom assemblage data from the mixed layer and surface sediments (3760 m) around South Georgia. The relative proportion of diatom resting spores within diatom assemblages increases as a function of depth and is explained by selective preservation of their robust frustules. Our study highlights the significance of diatom resting spore export as a carbon vector out of the mixed layer. Furthermore, the contribution or resting spores to POC flux in the bathypelagic ocean and sediments suggests they play a particularly important role in sequestering biologically fixed CO2 over climatically relevant timescales. |
format |
Article in Journal/Newspaper |
author |
Rembauville, M Manno, C Tarling, G. A. Blain, S. Salter, I |
spellingShingle |
Rembauville, M Manno, C Tarling, G. A. Blain, S. Salter, I Strong contribution of diatom resting spores to deep sea carbon export fluxes in the naturally iron fertilized waters downstream of South Georgia |
author_facet |
Rembauville, M Manno, C Tarling, G. A. Blain, S. Salter, I |
author_sort |
Rembauville, M |
title |
Strong contribution of diatom resting spores to deep sea carbon export fluxes in the naturally iron fertilized waters downstream of South Georgia |
title_short |
Strong contribution of diatom resting spores to deep sea carbon export fluxes in the naturally iron fertilized waters downstream of South Georgia |
title_full |
Strong contribution of diatom resting spores to deep sea carbon export fluxes in the naturally iron fertilized waters downstream of South Georgia |
title_fullStr |
Strong contribution of diatom resting spores to deep sea carbon export fluxes in the naturally iron fertilized waters downstream of South Georgia |
title_full_unstemmed |
Strong contribution of diatom resting spores to deep sea carbon export fluxes in the naturally iron fertilized waters downstream of South Georgia |
title_sort |
strong contribution of diatom resting spores to deep sea carbon export fluxes in the naturally iron fertilized waters downstream of south georgia |
publisher |
PERGAMON-ELSEVIER SCIENCE LTD |
publishDate |
2016 |
url |
https://epic.awi.de/id/eprint/41042/ https://epic.awi.de/id/eprint/41042/1/Rembauville_et_al_2016c_Deep_Sea_Research_I.pdf https://hdl.handle.net/10013/epic.48001 https://hdl.handle.net/10013/epic.48001.d001 |
geographic |
Antarctic Southern Ocean The Antarctic |
geographic_facet |
Antarctic Southern Ocean The Antarctic |
genre |
Antarc* Antarctic Antarctica Southern Ocean |
genre_facet |
Antarc* Antarctic Antarctica Southern Ocean |
op_source |
EPIC3Deep-Sea Research Part I-Oceanographic Research Papers, PERGAMON-ELSEVIER SCIENCE LTD, 115, pp. 22-35, ISSN: 0967-0637 |
op_relation |
https://epic.awi.de/id/eprint/41042/1/Rembauville_et_al_2016c_Deep_Sea_Research_I.pdf https://hdl.handle.net/10013/epic.48001.d001 Rembauville, M. , Manno, C. , Tarling, G. A. , Blain, S. and Salter, I. orcid:0000-0002-4513-0314 (2016) Strong contribution of diatom resting spores to deep sea carbon export fluxes in the naturally iron fertilized waters downstream of South Georgia , Deep-Sea Research Part I-Oceanographic Research Papers, 115 , pp. 22-35 . doi:10.1016/j.dsr.2016.05.002 <https://doi.org/10.1016/j.dsr.2016.05.002> , hdl:10013/epic.48001 |
op_doi |
https://doi.org/10.1016/j.dsr.2016.05.002 |
container_title |
Deep Sea Research Part I: Oceanographic Research Papers |
container_volume |
115 |
container_start_page |
22 |
op_container_end_page |
35 |
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1766135053314686976 |