Northeastern Atlantic benthic foraminifera during the last 45,000 years: Changes in productivity seen from the bottom up
We studied benthic foraminifera from the last 45 kyr in the >63 mu m size fraction in Biogeochemical Ocean Flux Studies (BOFS) cores 5K (50 degrees 41.3'N, 21 degrees 51.9'W, depth 3547 m) and 14K (58 degrees 37.2'N, 19 degrees 26.2'W, depth 1756 m), at a time resolution of se...
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ftucl:oai:eprints.ucl.ac.uk.OAI2:101338 2023-12-24T10:18:42+01:00 Northeastern Atlantic benthic foraminifera during the last 45,000 years: Changes in productivity seen from the bottom up Thomas, E Booth, L Maslin, M Shackleton, NJ 1995-06 application/pdf https://discovery.ucl.ac.uk/id/eprint/101338/1/94PA03056.pdf https://discovery.ucl.ac.uk/id/eprint/101338/ eng eng AMER GEOPHYSICAL UNION https://discovery.ucl.ac.uk/id/eprint/101338/1/94PA03056.pdf https://discovery.ucl.ac.uk/id/eprint/101338/ open Paleoceanography , 10 (3) 545 - 562. (1995) Seasonally deposited phytodetritus Subpolar North-Atlantic Deep-ocean circulation Equatorial Pacific Glacial maximum Southern-ocean Organic flux Microhabitat preferences Continental-margin Heinrich events Article 1995 ftucl 2023-11-27T13:07:30Z We studied benthic foraminifera from the last 45 kyr in the >63 mu m size fraction in Biogeochemical Ocean Flux Studies (BOFS) cores 5K (50 degrees 41.3'N, 21 degrees 51.9'W, depth 3547 m) and 14K (58 degrees 37.2'N, 19 degrees 26.2'W, depth 1756 m), at a time resolution of several hundreds to a thousand years. The deepest site showed the largest fluctuations in faunal composition, species richness, and benthic foraminiferal accumulation rates; the fluctuations resulted from changes in abundance of Epistominella exigua and Alabaminella weddellensis. In the present oceans, these species bloom opportunistically when a spring plankton bloom results in seasonal deposition of phytodetritus on the seafloor. The ''phytodetritus species'' had very low relative abundances and accumulation rates during the last glacial maximum. A strong increase in absolute and relative abundance of E. exigua and A weddellensis during deglaciation paralleled the decrease in abundance of the polar planktonic foraminifer Neogloboquadrina pachyderma (s), and the increase in abundance of warmer water planktonic species such as Globigerina bulloides. This strong increase in relative abundance of the ''phytodetritus species'' and the coeval increase in benthic foraminiferal accumulation rate were thus probably caused by an increase in the deposition of phytodetritus to the seafloor (and thus probably of surface productivity) when the polar front retreated to higher latitudes. The abundance of ''phytodetritus species'' decreased during the Younger Dryas, but not to the low levels of fully glacial conditions. During Heinrich events (periods of excessive melt-water formation and ice rafting) benthic accumulation rates were very low, as were the absolute and relative abundances of the ''phytodetritus species'', supporting suggestions that surface productivity was very low during these events. In both cores Pullenia and Cassidulina species were common during isotope stages 2, 3 and 4, as were bolivinid, buliminid and uvigerinid species. High ... Article in Journal/Newspaper Neogloboquadrina pachyderma North Atlantic Southern Ocean University College London: UCL Discovery Southern Ocean Pacific |
institution |
Open Polar |
collection |
University College London: UCL Discovery |
op_collection_id |
ftucl |
language |
English |
topic |
Seasonally deposited phytodetritus Subpolar North-Atlantic Deep-ocean circulation Equatorial Pacific Glacial maximum Southern-ocean Organic flux Microhabitat preferences Continental-margin Heinrich events |
spellingShingle |
Seasonally deposited phytodetritus Subpolar North-Atlantic Deep-ocean circulation Equatorial Pacific Glacial maximum Southern-ocean Organic flux Microhabitat preferences Continental-margin Heinrich events Thomas, E Booth, L Maslin, M Shackleton, NJ Northeastern Atlantic benthic foraminifera during the last 45,000 years: Changes in productivity seen from the bottom up |
topic_facet |
Seasonally deposited phytodetritus Subpolar North-Atlantic Deep-ocean circulation Equatorial Pacific Glacial maximum Southern-ocean Organic flux Microhabitat preferences Continental-margin Heinrich events |
description |
We studied benthic foraminifera from the last 45 kyr in the >63 mu m size fraction in Biogeochemical Ocean Flux Studies (BOFS) cores 5K (50 degrees 41.3'N, 21 degrees 51.9'W, depth 3547 m) and 14K (58 degrees 37.2'N, 19 degrees 26.2'W, depth 1756 m), at a time resolution of several hundreds to a thousand years. The deepest site showed the largest fluctuations in faunal composition, species richness, and benthic foraminiferal accumulation rates; the fluctuations resulted from changes in abundance of Epistominella exigua and Alabaminella weddellensis. In the present oceans, these species bloom opportunistically when a spring plankton bloom results in seasonal deposition of phytodetritus on the seafloor. The ''phytodetritus species'' had very low relative abundances and accumulation rates during the last glacial maximum. A strong increase in absolute and relative abundance of E. exigua and A weddellensis during deglaciation paralleled the decrease in abundance of the polar planktonic foraminifer Neogloboquadrina pachyderma (s), and the increase in abundance of warmer water planktonic species such as Globigerina bulloides. This strong increase in relative abundance of the ''phytodetritus species'' and the coeval increase in benthic foraminiferal accumulation rate were thus probably caused by an increase in the deposition of phytodetritus to the seafloor (and thus probably of surface productivity) when the polar front retreated to higher latitudes. The abundance of ''phytodetritus species'' decreased during the Younger Dryas, but not to the low levels of fully glacial conditions. During Heinrich events (periods of excessive melt-water formation and ice rafting) benthic accumulation rates were very low, as were the absolute and relative abundances of the ''phytodetritus species'', supporting suggestions that surface productivity was very low during these events. In both cores Pullenia and Cassidulina species were common during isotope stages 2, 3 and 4, as were bolivinid, buliminid and uvigerinid species. High ... |
format |
Article in Journal/Newspaper |
author |
Thomas, E Booth, L Maslin, M Shackleton, NJ |
author_facet |
Thomas, E Booth, L Maslin, M Shackleton, NJ |
author_sort |
Thomas, E |
title |
Northeastern Atlantic benthic foraminifera during the last 45,000 years: Changes in productivity seen from the bottom up |
title_short |
Northeastern Atlantic benthic foraminifera during the last 45,000 years: Changes in productivity seen from the bottom up |
title_full |
Northeastern Atlantic benthic foraminifera during the last 45,000 years: Changes in productivity seen from the bottom up |
title_fullStr |
Northeastern Atlantic benthic foraminifera during the last 45,000 years: Changes in productivity seen from the bottom up |
title_full_unstemmed |
Northeastern Atlantic benthic foraminifera during the last 45,000 years: Changes in productivity seen from the bottom up |
title_sort |
northeastern atlantic benthic foraminifera during the last 45,000 years: changes in productivity seen from the bottom up |
publisher |
AMER GEOPHYSICAL UNION |
publishDate |
1995 |
url |
https://discovery.ucl.ac.uk/id/eprint/101338/1/94PA03056.pdf https://discovery.ucl.ac.uk/id/eprint/101338/ |
geographic |
Southern Ocean Pacific |
geographic_facet |
Southern Ocean Pacific |
genre |
Neogloboquadrina pachyderma North Atlantic Southern Ocean |
genre_facet |
Neogloboquadrina pachyderma North Atlantic Southern Ocean |
op_source |
Paleoceanography , 10 (3) 545 - 562. (1995) |
op_relation |
https://discovery.ucl.ac.uk/id/eprint/101338/1/94PA03056.pdf https://discovery.ucl.ac.uk/id/eprint/101338/ |
op_rights |
open |
_version_ |
1786208202138845184 |