Biogeochemical proxies and diatoms in surface sediments across the Drake Passage reflect oceanic domains and frontal systems in the region
The Antarctic Circumpolar Current is the world's largest current system connecting all major ocean basins of the global ocean. Its flow, driven by strong westerly winds, is constricted to its narrowest extent in the Drake Passage, located between South America and the Antarctic Peninsula. Due t...
Published in: | Progress in Oceanography |
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Main Authors: | , , , , , , , , , , , |
Format: | Article in Journal/Newspaper |
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2019
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Online Access: | https://epic.awi.de/id/eprint/49687/ http://www.sciencedirect.com/science/article/pii/S0079661118301903 https://hdl.handle.net/10013/epic.75615f60-2aa1-4984-964b-76cf3cb6958e |
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institution |
Open Polar |
collection |
Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) |
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ftawi |
language |
unknown |
description |
The Antarctic Circumpolar Current is the world's largest current system connecting all major ocean basins of the global ocean. Its flow, driven by strong westerly winds, is constricted to its narrowest extent in the Drake Passage, located between South America and the Antarctic Peninsula. Due to the remoteness of the area, harsh weather conditions and strong bottom currents, sediment recovery is difficult and data coverage is still inadequate. Here, we report on the composition of 51 surface sediments collected during the R/V Polarstern PS97 expedition (Februaryâ-April 2016) across the western and central Drake Passage, from the Chilean/Argentinian continental margin to the South Shetland Islands and the Bransfield Strait (water depth: ∼100–4000 m). We studied microfossils (diatoms), bulk sediment composition and geochemical proxies (biogenic opal, organic carbon, calcium carbonate, carbon and nitrogen stable isotopes, sterols and photosynthetic pigments), and evaluated how they respond to, and reflect oceanic domains and polar to subpolar frontal systems in this region. Our multi-proxy approach shows a strong relationship between the composition of surface sediments and ocean productivity, terrigenous input, intensity of ocean currents, and ice proximity, clearly differentiating among 4 biogeographical zones. The Subantarctic Zone was characterized by warmer-water diatoms, high carbonate (>45) and low organic carbon contents (avg. 0.26), as well as low concentrations of pigments (avg. 1.75 μg/g) and sterols (avg. 0.90 μg/g). A general N-S transition from carbonate-rich to opal-rich sediment was observed at Drake Passage sites of the Polar Front and Permanently Open Ocean Zone. These sites were characterized by low organic carbon content (0.22), high relative abundances of heavily silicified diatoms (≥60% Fragilariopsis kerguelensis), and abundant foraminifera at shallower stations. Approaching the Antarctic Peninsula in the Transitional Zone, an increase in the concentrations of pigments and sterols (avg. 2.57 μg/g and 1.44 μg/g, respectively) and a strong decrease in carbonate content was observed. The seasonal Sea-Ice Zone in the southern section of the study area, had the highest contents of biogenic opal (avg. 14.6) and organic carbon (avg. 0.7), low carbonate contents (avg. 2.4), with the occurrence of sea-ice-related diatoms and sterols. In all zones, terrigenous input was detected, although carbon/nitrogen ratios and δ13Corg suggest a predominance of marine-derived organic matter; lower values of δ13Corg occurred south of the Polar Front. The new results presented here constitute a highly valuable reference dataset for the calibration of microfossil and geochemical proxies against observational data and provide a useful regional baseline for future paleo-research. |
format |
Article in Journal/Newspaper |
author |
Cárdenas, Paola Lange, Carina B. Vernet, Maria Esper, Oliver Srain, Benjamin Vorrath, Maria-Elena Ehrhardt, Sophie Müller, Juliane Kuhn, Gerhard Arz, Helge W. Lembke-Jene, Lester Lamy, Frank |
spellingShingle |
Cárdenas, Paola Lange, Carina B. Vernet, Maria Esper, Oliver Srain, Benjamin Vorrath, Maria-Elena Ehrhardt, Sophie Müller, Juliane Kuhn, Gerhard Arz, Helge W. Lembke-Jene, Lester Lamy, Frank Biogeochemical proxies and diatoms in surface sediments across the Drake Passage reflect oceanic domains and frontal systems in the region |
author_facet |
Cárdenas, Paola Lange, Carina B. Vernet, Maria Esper, Oliver Srain, Benjamin Vorrath, Maria-Elena Ehrhardt, Sophie Müller, Juliane Kuhn, Gerhard Arz, Helge W. Lembke-Jene, Lester Lamy, Frank |
author_sort |
Cárdenas, Paola |
title |
Biogeochemical proxies and diatoms in surface sediments across the Drake Passage reflect oceanic domains and frontal systems in the region |
title_short |
Biogeochemical proxies and diatoms in surface sediments across the Drake Passage reflect oceanic domains and frontal systems in the region |
title_full |
Biogeochemical proxies and diatoms in surface sediments across the Drake Passage reflect oceanic domains and frontal systems in the region |
title_fullStr |
Biogeochemical proxies and diatoms in surface sediments across the Drake Passage reflect oceanic domains and frontal systems in the region |
title_full_unstemmed |
Biogeochemical proxies and diatoms in surface sediments across the Drake Passage reflect oceanic domains and frontal systems in the region |
title_sort |
biogeochemical proxies and diatoms in surface sediments across the drake passage reflect oceanic domains and frontal systems in the region |
publishDate |
2019 |
url |
https://epic.awi.de/id/eprint/49687/ http://www.sciencedirect.com/science/article/pii/S0079661118301903 https://hdl.handle.net/10013/epic.75615f60-2aa1-4984-964b-76cf3cb6958e |
geographic |
Antarctic The Antarctic Antarctic Peninsula Drake Passage South Shetland Islands Bransfield Strait |
geographic_facet |
Antarctic The Antarctic Antarctic Peninsula Drake Passage South Shetland Islands Bransfield Strait |
genre |
Antarc* Antarctic Antarctic Peninsula Bransfield Strait Drake Passage Sea ice South Shetland Islands |
genre_facet |
Antarc* Antarctic Antarctic Peninsula Bransfield Strait Drake Passage Sea ice South Shetland Islands |
op_source |
EPIC3Progress in Oceanography, 174, pp. 72 - 88 |
op_relation |
Cárdenas, P. , Lange, C. B. , Vernet, M. , Esper, O. orcid:0000-0002-4342-3471 , Srain, B. , Vorrath, M. E. orcid:0000-0001-7208-1186 , Ehrhardt, S. , Müller, J. orcid:0000-0003-0724-4131 , Kuhn, G. , Arz, H. W. , Lembke-Jene, L. orcid:0000-0002-6873-8533 and Lamy, F. orcid:0000-0001-5952-1765 (2019) Biogeochemical proxies and diatoms in surface sediments across the Drake Passage reflect oceanic domains and frontal systems in the region , Progress in Oceanography, 174 , 72 - 88 . doi:10.1016/j.pocean.2018.10.004 <https://doi.org/10.1016/j.pocean.2018.10.004> , hdl:10013/epic.75615f60-2aa1-4984-964b-76cf3cb6958e |
op_doi |
https://doi.org/10.1016/j.pocean.2018.10.004 |
container_title |
Progress in Oceanography |
container_volume |
174 |
container_start_page |
72 |
op_container_end_page |
88 |
_version_ |
1766221641606496256 |
spelling |
ftawi:oai:epic.awi.de:49687 2023-05-15T13:45:21+02:00 Biogeochemical proxies and diatoms in surface sediments across the Drake Passage reflect oceanic domains and frontal systems in the region Cárdenas, Paola Lange, Carina B. Vernet, Maria Esper, Oliver Srain, Benjamin Vorrath, Maria-Elena Ehrhardt, Sophie Müller, Juliane Kuhn, Gerhard Arz, Helge W. Lembke-Jene, Lester Lamy, Frank 2019-10 https://epic.awi.de/id/eprint/49687/ http://www.sciencedirect.com/science/article/pii/S0079661118301903 https://hdl.handle.net/10013/epic.75615f60-2aa1-4984-964b-76cf3cb6958e unknown Cárdenas, P. , Lange, C. B. , Vernet, M. , Esper, O. orcid:0000-0002-4342-3471 , Srain, B. , Vorrath, M. E. orcid:0000-0001-7208-1186 , Ehrhardt, S. , Müller, J. orcid:0000-0003-0724-4131 , Kuhn, G. , Arz, H. W. , Lembke-Jene, L. orcid:0000-0002-6873-8533 and Lamy, F. orcid:0000-0001-5952-1765 (2019) Biogeochemical proxies and diatoms in surface sediments across the Drake Passage reflect oceanic domains and frontal systems in the region , Progress in Oceanography, 174 , 72 - 88 . doi:10.1016/j.pocean.2018.10.004 <https://doi.org/10.1016/j.pocean.2018.10.004> , hdl:10013/epic.75615f60-2aa1-4984-964b-76cf3cb6958e EPIC3Progress in Oceanography, 174, pp. 72 - 88 Article isiRev 2019 ftawi https://doi.org/10.1016/j.pocean.2018.10.004 2021-12-24T15:44:44Z The Antarctic Circumpolar Current is the world's largest current system connecting all major ocean basins of the global ocean. Its flow, driven by strong westerly winds, is constricted to its narrowest extent in the Drake Passage, located between South America and the Antarctic Peninsula. Due to the remoteness of the area, harsh weather conditions and strong bottom currents, sediment recovery is difficult and data coverage is still inadequate. Here, we report on the composition of 51 surface sediments collected during the R/V Polarstern PS97 expedition (Februaryâ-April 2016) across the western and central Drake Passage, from the Chilean/Argentinian continental margin to the South Shetland Islands and the Bransfield Strait (water depth: ∼100–4000 m). We studied microfossils (diatoms), bulk sediment composition and geochemical proxies (biogenic opal, organic carbon, calcium carbonate, carbon and nitrogen stable isotopes, sterols and photosynthetic pigments), and evaluated how they respond to, and reflect oceanic domains and polar to subpolar frontal systems in this region. Our multi-proxy approach shows a strong relationship between the composition of surface sediments and ocean productivity, terrigenous input, intensity of ocean currents, and ice proximity, clearly differentiating among 4 biogeographical zones. The Subantarctic Zone was characterized by warmer-water diatoms, high carbonate (>45) and low organic carbon contents (avg. 0.26), as well as low concentrations of pigments (avg. 1.75 μg/g) and sterols (avg. 0.90 μg/g). A general N-S transition from carbonate-rich to opal-rich sediment was observed at Drake Passage sites of the Polar Front and Permanently Open Ocean Zone. These sites were characterized by low organic carbon content (0.22), high relative abundances of heavily silicified diatoms (≥60% Fragilariopsis kerguelensis), and abundant foraminifera at shallower stations. Approaching the Antarctic Peninsula in the Transitional Zone, an increase in the concentrations of pigments and sterols (avg. 2.57 μg/g and 1.44 μg/g, respectively) and a strong decrease in carbonate content was observed. The seasonal Sea-Ice Zone in the southern section of the study area, had the highest contents of biogenic opal (avg. 14.6) and organic carbon (avg. 0.7), low carbonate contents (avg. 2.4), with the occurrence of sea-ice-related diatoms and sterols. In all zones, terrigenous input was detected, although carbon/nitrogen ratios and δ13Corg suggest a predominance of marine-derived organic matter; lower values of δ13Corg occurred south of the Polar Front. The new results presented here constitute a highly valuable reference dataset for the calibration of microfossil and geochemical proxies against observational data and provide a useful regional baseline for future paleo-research. Article in Journal/Newspaper Antarc* Antarctic Antarctic Peninsula Bransfield Strait Drake Passage Sea ice South Shetland Islands Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) Antarctic The Antarctic Antarctic Peninsula Drake Passage South Shetland Islands Bransfield Strait Progress in Oceanography 174 72 88 |