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Carbon-13 in Uvigerina: Tropical Rainforest History and the Equatorial Pacific Carbonate Dissolution Cycles.

ADA049905

Publication Date	1977
Personal Author	Shackleton, N. J.
Page Count	28
Abstract	Benthonic foraminifera in late Pleistocene deep-sea cores show significant variation in sigma 13cC with depth in sediment. This, and the report by Sommer et al.(in prep.) of sigma 13C variations in planktonic foraminifera, indicate that sigma 13C in dissolved oceanic C02 undergoes a significant change in a few thousand years. This is in apparent contradiction to the estimated 300 ka residence time for carbon in the ocean. It is suggested that this is a consequence of changes in the terrestrial plant biomass, which has a sigma 13C of about -25/00. Postulated changes in world vegetation, particularly in tropical rainforests during the late pleistocene, were sufficient to produce a change of the magnitude observed. Rapid expansion of forests between 13 ka and 8 ka ago may have resulted in the striking accumulation of aragonite pteropods in Atlantic Ocean sediments of that age. Rapid deforestation during an interglacial-glacial transition probably caused the intense carbonate dissolution which is observed in Equatorial Pacific Ocean sediments deposited over this interval. The current rate of injection of fossil fuel C02 into the atmosphere is substantially greater than the rate at which it was added during post-interglacial aridification in the tropics.
Keywords	Marine geology Forests Glacial geology Geologic age determination Carbon isotopes Stable isotopes Benthos Foraminifera Micropaleontology Fossil fuels Ocean bottom sampling Cores Sedimentology Tropical regions Pacific Ocean Equatorial regions Deep Oceans Glacial deposits Reprints Carbon 13 Paleoclimatology Biomass Carbon dioxide
Source Agency	Non Paid Reprints
NTIS Subject Category	48F - Geology & Geophysics 47C - Physical & Chemical Oceanography
Corporate Authors	Lamont-Doherty Geological Observatory Palisades N Y
Document Type	Journal Article
NTIS Issue Number	197809
Contract Number	N00014-75-C-0210

Carbon-13 in Uvigerina: Tropical Rainforest History and the Equatorial Pacific Carbonate Dissolution Cycles.

Carbon-13 in Uvigerina: Tropical Rainforest History and the Equatorial Pacific Carbonate Dissolution Cycles.
ADA049905

Publication Date	1977
Personal Author	Shackleton, N. J.
Page Count	28
Abstract	Benthonic foraminifera in late Pleistocene deep-sea cores show significant variation in sigma 13cC with depth in sediment. This, and the report by Sommer et al.(in prep.) of sigma 13C variations in planktonic foraminifera, indicate that sigma 13C in dissolved oceanic C02 undergoes a significant change in a few thousand years. This is in apparent contradiction to the estimated 300 ka residence time for carbon in the ocean. It is suggested that this is a consequence of changes in the terrestrial plant biomass, which has a sigma 13C of about -25/00. Postulated changes in world vegetation, particularly in tropical rainforests during the late pleistocene, were sufficient to produce a change of the magnitude observed. Rapid expansion of forests between 13 ka and 8 ka ago may have resulted in the striking accumulation of aragonite pteropods in Atlantic Ocean sediments of that age. Rapid deforestation during an interglacial-glacial transition probably caused the intense carbonate dissolution which is observed in Equatorial Pacific Ocean sediments deposited over this interval. The current rate of injection of fossil fuel C02 into the atmosphere is substantially greater than the rate at which it was added during post-interglacial aridification in the tropics.
Keywords	Marine geology Forests Glacial geology Geologic age determination Carbon isotopes Stable isotopes Benthos Foraminifera Micropaleontology Fossil fuels Ocean bottom sampling Cores Sedimentology Tropical regions Pacific Ocean Equatorial regions Deep Oceans Glacial deposits Reprints Carbon 13 Paleoclimatology Biomass Carbon dioxide
Source Agency	Non Paid Reprints
NTIS Subject Category	48F - Geology & Geophysics 47C - Physical & Chemical Oceanography
Corporate Authors	Lamont-Doherty Geological Observatory Palisades N Y
Document Type	Journal Article
NTIS Issue Number	197809
Contract Number	N00014-75-C-0210