The Role of Biological Production in Pleistocene Atmospheric Carbon Dioxide Variations and the Nitrogen Isotope Dynamics of the Southern Ocean.

• Main Author: Sigman, Daniel M.
• Other Authors: WOODS HOLE OCEANOGRAPHIC INSTITUTION MA
• Format: Text
• Language: English
• Published: 1997
• Subjects: Atmospheric Physics; Isotopes; *NITROGEN; *ISOTOPES; *CARBON DIOXIDE; *ATMOSPHERIC CHEMISTRY; EQUATORIAL REGIONS; PRODUCTION; BIOLOGY; MODELS; DYNAMICS; SATURATION; CALCITE; HYPOTHESES; OCEANS; PRESERVATION; SOUTH(DIRECTION); LATITUDE; Southern Ocean
• Online Access: http://www.dtic.mil/docs/citations/ADA342811; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA342811

This dissertation contributes to the search for a cause of glacial/interglacial variations in atmospheric carbon dioxide. The hypotheses addressed involve changes in low and high-latitude biological export production. A modelling exercise demonstrates that the paleoceanographic record of calcite preservation places constraints on hypothesized changes in low latitude biological production. The model results indicate that large, production-driven changes in the depth of the calcite saturation horizon during the last ice age would have caused a similar deepening of the calcite lysocline, even when the effect of sediment respiration-driven dissolution is considered. Such a large glacial lysocline deepening is not evident on an ocean-average basis. The results indicate very few mechanisms by which low latitude production could have driven Pleisotocene carbon dioxide variations, generally arguing against a low latitude cause for these variations.