Larger CO(2) source at the equatorial Pacific during the last deglaciation

While biogeochemical and physical processes in the Southern Ocean are thought to be central to atmospheric CO(2) rise during the last deglaciation, the role of the equatorial Pacific, where the largest CO(2) source exists at present, remains largely unconstrained. Here we present seawater pH and pCO(2) variations from fossil Porites corals in the mid equatorial Pacific offshore Tahiti based on a newly calibrated boron isotope paleo-pH proxy. Our new data, together with recalibrated existing data, indicate that a significant pCO(2) increase (pH decrease), accompanied by anomalously large marine (14)C reservoir ages, occurred following not only the Younger Dryas, but also Heinrich Stadial 1. These findings indicate an expanded zone of equatorial upwelling and resultant CO(2) emission, which may be derived from higher subsurface dissolved inorganic carbon concentration.