Glacial-Holocene changes in atmospheric CO2 and the deep-sea record

Reconstruction of Low and Middle Latitude Export Productivity, 30,000 Years BP to Present: Implications for Global Carbon Reservoirs

“…Accordingly, we may expect a more polarized distribution of the nutrient inventory in the glacial surface ocean than for the distribution today, with a shift from the widespread low-productivity zones to the narrow high-productivity zones. Furthermore, this shift will induce a general increase in the 'rain ratio,' which varies nonlinearly with the strength of the productivity (Berger and Keir, 1984) and produces, in turn, an increase in (deep) ocean alkalinity (Boyle, 1988). This mechanism possibly has the potential to explain the carbonate dissolution spikes that are characteristic of the abrupt clirnatic change linked to the onset of glaciations.…”

“…In harmony with Berger and Vincent (1986), Boyle (1988) inferred that the CO 2 -induced higher acidity of the bottom water temporarily increased the carbonate dissolution and, hence, the oceanic alkalinity. With a delay of about 3000 years, this higher alkalinity resulted in an extraction of CO 2 from the atmosphere to the ocean, a mechanism that is related to, and enhances, the general effect of the organic carbonlcarbonate carbon rain ratio proposed by Berger and Keir (1984).…”

“…This glacial-to-interglacial difference had a considerable feedback on global climatic cooling and warming (Hansen et al, 1984) and on the climatic link between the Northem and Southem Hemispheres (Mitchell, 1988). The scientific community has largely agreed that combined variations in the "biological pump" (Berger and Keir, 1984) driving carbon dioxide into the deep ocean, and in the chemical and physical circulations of the ocean, must provide the dominant forcings for the observed changes in atmospheric CO 2 • In this context numerous models were proposed and examined in the literature (Sundquist and Broecker, 1985) 319 M. E. Schlesinger (ed. ), Most receotly, Boyle (1988) calculated and tested a model that recogoizes the primary driviog factor for atmospheric pC02change to be a glacial rearrangement of the vertical ocean chemistry distributions, that is~ a global shift of labile nutrients and (isotopically light) metabolic CO 2 from the Intermediate Water to the deep ocean.…”

“…Special attention is given to the narrow high-productivity belts in low latitudes. Based on the distribution patterns (Koblentz-Mishke et al, 1970) and empirical relationships found by Eppley and Peterson (1979) and Berger and Keir (1984), these belts may be expected to dominate the budgets of vertical carbon transfer in the ocean. Moreover, we document the carbon isotopic response of the ocean to paleoproductivity changes, in particular, the phase relationships between the oceanic response, productivity variations and atmospheric pC0 2 changes, to arrive at a better understanding of the possible forcing chains for c1imatic change.…”

Pliocene-Pleistocene Carbon Isotope Record, Site 586, Ontong Java Plateau

“…Organic carbon is depleted in 13 C; building up a reservoir, therefore, enriches the ocean in the heavy isotope, and vice versa (Tappan, 1968;Fischer and Arthur, 1977;Shackleton, 1977;Vincent and Berger, 1985;Woodruff et al, 1985;Raymo et al, 1989). The glacial-to-interglacial contrast for the last cycle, for example, is between 0.4‰ and 0.5‰ (Berger and Keir, 1984;Herguera et al, 1992), which corresponds to a transfer of carbon of approximately one atmospheric carbon mass (ACM) in and out of organic pools.…”