Environmental factors affecting planktonic foraminifera abundance and distribution in the Northeast Gulf of Mexico
The shell composition of planktonic foraminifera used in many paleoreconstructions assumes they are accurately representing conditions at the surface/mixed layer. However, planktonic foraminifera are known to inhabit a depth range that extends below the mixed layer. In the present study, foraminifer...
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fttexasamuniv:oai:oaktrust.library.tamu.edu:1969.1/2251 2023-07-16T04:00:33+02:00 Environmental factors affecting planktonic foraminifera abundance and distribution in the Northeast Gulf of Mexico Ravula, Sharath Reddy Slowey, Niall Wormuth, John Malone, Mitch 2005-08-29 1866750 bytes electronic application/pdf born digital https://hdl.handle.net/1969.1/2251 en_US eng Texas A&M University https://hdl.handle.net/1969.1/2251 planktonic foraminifera MOCNESS environmental factors Book Thesis Electronic Thesis text 2005 fttexasamuniv 2023-06-27T23:04:22Z The shell composition of planktonic foraminifera used in many paleoreconstructions assumes they are accurately representing conditions at the surface/mixed layer. However, planktonic foraminifera are known to inhabit a depth range that extends below the mixed layer. In the present study, foraminifera were collected at discrete depth intervals using a Multiple Opening and Closing Net Environmental Sensing System (MOCNESS) in either cyclonic or anticyclonic eddies that had contrasting environmental conditions. The foraminifera abundances and distributions were compared to the water depth, temperature, density, and chlorophyll profiles. Nine species were found consistently among all the tows and composed at least 96% of the species found, though a shift in the species abundances and depths occurred between eddies. Species occurred where physical factors were compatible with conditions and feeding opportunities they were adapted to. Three species pink and white Globigerinoides ruber and Globigerinoides sacculifer thrived best when a steep density gradient resulted in a shallower mixed-layer that restricted them under more intense light and allowed them to better exploit their algae symbionts. Globigerina bulloides was found outside its sub-polar habitat because the waters of the cyclones were cool enough (less than 26??C) at the same depths that sufficient chlorophyll was available. Two species Orbulina universa, and Globorotalia menardii were consistently absent in the mixed layer, but tracked deeper chlorophyll concentrations. Three other species were found inconsistently among the tows: Hastigerina pelagica, Globigerinella siphonifera, and Globigerinella calida. H. pelagica probably follows chlorophyll concentrations. G. siphonifera, and G. calida have a preference for deeper waters within the photic zone. The drastic doubling to tripling of the foraminifera abundances in cyclones biases downcore reconstructions of sea surface temperature towards cooler conditions. Also, the shift in species composition between ... Book Planktonic foraminifera Texas A&M University Digital Repository |
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Texas A&M University Digital Repository |
op_collection_id |
fttexasamuniv |
language |
English |
topic |
planktonic foraminifera MOCNESS environmental factors |
spellingShingle |
planktonic foraminifera MOCNESS environmental factors Ravula, Sharath Reddy Environmental factors affecting planktonic foraminifera abundance and distribution in the Northeast Gulf of Mexico |
topic_facet |
planktonic foraminifera MOCNESS environmental factors |
description |
The shell composition of planktonic foraminifera used in many paleoreconstructions assumes they are accurately representing conditions at the surface/mixed layer. However, planktonic foraminifera are known to inhabit a depth range that extends below the mixed layer. In the present study, foraminifera were collected at discrete depth intervals using a Multiple Opening and Closing Net Environmental Sensing System (MOCNESS) in either cyclonic or anticyclonic eddies that had contrasting environmental conditions. The foraminifera abundances and distributions were compared to the water depth, temperature, density, and chlorophyll profiles. Nine species were found consistently among all the tows and composed at least 96% of the species found, though a shift in the species abundances and depths occurred between eddies. Species occurred where physical factors were compatible with conditions and feeding opportunities they were adapted to. Three species pink and white Globigerinoides ruber and Globigerinoides sacculifer thrived best when a steep density gradient resulted in a shallower mixed-layer that restricted them under more intense light and allowed them to better exploit their algae symbionts. Globigerina bulloides was found outside its sub-polar habitat because the waters of the cyclones were cool enough (less than 26??C) at the same depths that sufficient chlorophyll was available. Two species Orbulina universa, and Globorotalia menardii were consistently absent in the mixed layer, but tracked deeper chlorophyll concentrations. Three other species were found inconsistently among the tows: Hastigerina pelagica, Globigerinella siphonifera, and Globigerinella calida. H. pelagica probably follows chlorophyll concentrations. G. siphonifera, and G. calida have a preference for deeper waters within the photic zone. The drastic doubling to tripling of the foraminifera abundances in cyclones biases downcore reconstructions of sea surface temperature towards cooler conditions. Also, the shift in species composition between ... |
author2 |
Slowey, Niall Wormuth, John Malone, Mitch |
format |
Book |
author |
Ravula, Sharath Reddy |
author_facet |
Ravula, Sharath Reddy |
author_sort |
Ravula, Sharath Reddy |
title |
Environmental factors affecting planktonic foraminifera abundance and distribution in the Northeast Gulf of Mexico |
title_short |
Environmental factors affecting planktonic foraminifera abundance and distribution in the Northeast Gulf of Mexico |
title_full |
Environmental factors affecting planktonic foraminifera abundance and distribution in the Northeast Gulf of Mexico |
title_fullStr |
Environmental factors affecting planktonic foraminifera abundance and distribution in the Northeast Gulf of Mexico |
title_full_unstemmed |
Environmental factors affecting planktonic foraminifera abundance and distribution in the Northeast Gulf of Mexico |
title_sort |
environmental factors affecting planktonic foraminifera abundance and distribution in the northeast gulf of mexico |
publisher |
Texas A&M University |
publishDate |
2005 |
url |
https://hdl.handle.net/1969.1/2251 |
genre |
Planktonic foraminifera |
genre_facet |
Planktonic foraminifera |
op_relation |
https://hdl.handle.net/1969.1/2251 |
_version_ |
1771549455510667264 |