Models for changes in atmospheric carbon dioxide, ocean geochemistry and circulation during the late Pleistocene
This report provides a review of various hypotheses put forward so far as to the role of the oceans in controlling the glacial-interglacial climatic cycles through controls on the atmospheric carbon dioxide. The available paleochemical data appear to provide little support for the hypotheses involvi...
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ftnio:oai:dsr.nio.org:2264/2476 2023-05-15T13:59:28+02:00 Models for changes in atmospheric carbon dioxide, ocean geochemistry and circulation during the late Pleistocene Naqvi, S.W.A. SenGupta, R. 1990 http://drs.nio.org/drs/handle/2264/2476 en eng Vikas Publication Copyright [1990]. All efforts have been made to respect the copyright to the best of our knowledge. Inadvertent omissions, if brought to our notice, stand for correction and withdrawal of document from this repository. atmospheric gases atmospheric chemistry carbon dioxide geochemistry ocean circulation palaeoclimate pleistocene models Book Chapter 1990 ftnio 2012-08-25T20:07:21Z This report provides a review of various hypotheses put forward so far as to the role of the oceans in controlling the glacial-interglacial climatic cycles through controls on the atmospheric carbon dioxide. The available paleochemical data appear to provide little support for the hypotheses involving changes in the overall oceanic nutrient inventory, but there are definite indications of substantial differences in the water mass distribution during the glacial and interglacial times. A shift in the vertical chemical structure (greater accumulation of the labile nutrients and metabolic CO@d2@@ in the deep ocean at the expense of the intermediate layers during the ice ages), strongly suggested by the available data, could cause significant increases in oceanic alkalinity (and hence a decrease in atmospheric CO@d2@@) due to CaCO@d3@@ compensation. A likely mechanism for this rearrangement could be an orbital-forced insolation related increase in biological production in the Southern Ocean. This, coupled with greater production of the Antarctic Bottom Water (AABW) as compared to the North Atlantic Deep Water (NADW), seems to explain most of the observations. However, it is still not entirely clear how the system actually works. For example, the role of the dissolved organic matter (DOM) is being appreciated just now, but the factors which constrain the size of the oceanic DOM pool remain hitherto unknown. One of the major shortcomings of the models proposed so far is that they do not take into consideration the regionally varying responses of primary productivity and water circulation to the climatic changes. For example, given the unique seasonally varying circulation pattern and an acute deficiency in dissolved oxygen at mid-depth, the feedback mechanisms operating in the North Indian Ocean could substantially modify the magnitude of the global responses. However, very little data are presently available on the paleoceanography of this region to assess these effects Book Part Antarc* Antarctic NADW North Atlantic Deep Water North Atlantic Southern Ocean National Institute of Oceanography, India: Digital Repository Service (DRS@nio) Antarctic Indian Southern Ocean The Antarctic |
institution |
Open Polar |
collection |
National Institute of Oceanography, India: Digital Repository Service (DRS@nio) |
op_collection_id |
ftnio |
language |
English |
topic |
atmospheric gases atmospheric chemistry carbon dioxide geochemistry ocean circulation palaeoclimate pleistocene models |
spellingShingle |
atmospheric gases atmospheric chemistry carbon dioxide geochemistry ocean circulation palaeoclimate pleistocene models Naqvi, S.W.A. SenGupta, R. Models for changes in atmospheric carbon dioxide, ocean geochemistry and circulation during the late Pleistocene |
topic_facet |
atmospheric gases atmospheric chemistry carbon dioxide geochemistry ocean circulation palaeoclimate pleistocene models |
description |
This report provides a review of various hypotheses put forward so far as to the role of the oceans in controlling the glacial-interglacial climatic cycles through controls on the atmospheric carbon dioxide. The available paleochemical data appear to provide little support for the hypotheses involving changes in the overall oceanic nutrient inventory, but there are definite indications of substantial differences in the water mass distribution during the glacial and interglacial times. A shift in the vertical chemical structure (greater accumulation of the labile nutrients and metabolic CO@d2@@ in the deep ocean at the expense of the intermediate layers during the ice ages), strongly suggested by the available data, could cause significant increases in oceanic alkalinity (and hence a decrease in atmospheric CO@d2@@) due to CaCO@d3@@ compensation. A likely mechanism for this rearrangement could be an orbital-forced insolation related increase in biological production in the Southern Ocean. This, coupled with greater production of the Antarctic Bottom Water (AABW) as compared to the North Atlantic Deep Water (NADW), seems to explain most of the observations. However, it is still not entirely clear how the system actually works. For example, the role of the dissolved organic matter (DOM) is being appreciated just now, but the factors which constrain the size of the oceanic DOM pool remain hitherto unknown. One of the major shortcomings of the models proposed so far is that they do not take into consideration the regionally varying responses of primary productivity and water circulation to the climatic changes. For example, given the unique seasonally varying circulation pattern and an acute deficiency in dissolved oxygen at mid-depth, the feedback mechanisms operating in the North Indian Ocean could substantially modify the magnitude of the global responses. However, very little data are presently available on the paleoceanography of this region to assess these effects |
format |
Book Part |
author |
Naqvi, S.W.A. SenGupta, R. |
author_facet |
Naqvi, S.W.A. SenGupta, R. |
author_sort |
Naqvi, S.W.A. |
title |
Models for changes in atmospheric carbon dioxide, ocean geochemistry and circulation during the late Pleistocene |
title_short |
Models for changes in atmospheric carbon dioxide, ocean geochemistry and circulation during the late Pleistocene |
title_full |
Models for changes in atmospheric carbon dioxide, ocean geochemistry and circulation during the late Pleistocene |
title_fullStr |
Models for changes in atmospheric carbon dioxide, ocean geochemistry and circulation during the late Pleistocene |
title_full_unstemmed |
Models for changes in atmospheric carbon dioxide, ocean geochemistry and circulation during the late Pleistocene |
title_sort |
models for changes in atmospheric carbon dioxide, ocean geochemistry and circulation during the late pleistocene |
publisher |
Vikas Publication |
publishDate |
1990 |
url |
http://drs.nio.org/drs/handle/2264/2476 |
geographic |
Antarctic Indian Southern Ocean The Antarctic |
geographic_facet |
Antarctic Indian Southern Ocean The Antarctic |
genre |
Antarc* Antarctic NADW North Atlantic Deep Water North Atlantic Southern Ocean |
genre_facet |
Antarc* Antarctic NADW North Atlantic Deep Water North Atlantic Southern Ocean |
op_rights |
Copyright [1990]. All efforts have been made to respect the copyright to the best of our knowledge. Inadvertent omissions, if brought to our notice, stand for correction and withdrawal of document from this repository. |
_version_ |
1766268027631828992 |