![]() ![]() ![]() 2018 Jaccard and Galbraith 2012 Jacobel et al. Indeed, proxy reconstructions focused on dissolved oxygen and respired carbon consistently demonstrate the key role of respired carbon storage in the Pacific Ocean and its role in glacial atmospheric CO 2 minima (e.g. Zhao and Keigwin 2018), suggesting that direct reconstructions of water-mass carbon and oxygen concentrations are a more straightforward way to avoid these interpretive challenges. Numerous caveats to the ventilation age approach have been identified in recent years (e.g. Until recently, consensus on the significance of glacial respired carbon storage in the Pacific Ocean was hampered by conflicting interpretations procured in part from 14C-derived water-mass ventilation ages, taken to be indicative of carbon accumulation in the abyssal ocean. Figure composed using Ocean Data View with in situ data gridded using data-interpolating varational analysis (Schlitzer 2018). Data from the PACIFICA dataset (Suzuki et al. South-to-north transect from 150°W and west-to-east transect along the equator. Not only do these reconstructions help provide insight into the relative importance of different air-sea carbon exchange mechanisms, they also help us to balance the global carbon budget by quantifying how much additional carbon was stored in the glacial ocean.įigure 1: Modern distribution of oxygen in the Pacific Ocean. One way to tease apart these mechanisms is to reconstruct relative changes in the carbon storage of the ocean's various water masses, especially those which have biogeochemical signatures strongly influenced by processes occurring in the Southern Ocean that are propogated to other basins. The glacial drawdown of atmospheric CO 2 is thought to be largely a consequence of changes in southern high-latitude surface-ocean processes including increased CO 2 solubility, enhanced water-column stratification, decreased air-sea gas exchange, improved efficiency of the biological pump, and heightened ocean alkalinity (e.g. Over at least the last 800 kyr BP, glacial-interglacial cycles have been characterized by variations in atmospheric CO 2 concentrations of 50-100 ppm (Bereiter et al. ![]()
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