Current calcite (CaCO3) dissolution at the seafloor caused by anthropogenic CO2 (NCEI Accession 0176672)

• Main Authors: Sulpis, Olivier, Boudreau, Bernard P., Mucci, Alfonso, Jenkins, Chris, Trossman, David S., Arbic, Brian K., Key, Robert M.
• Format: Dataset
• Language: unknown
• Published: NOAA National Centers for Environmental Information 2018
• Subjects: Pacific; Indian; North Atlantic; Ocean acidification
• Online Access: https://dx.doi.org/10.25921/kbqy-4v05; https://www.ncei.noaa.gov/archive/accession/0176672

This dataset consists of current CaCO3 dissolution at the seafloor caused by anthropogenic CO2 in the World Oceans. This dataset contains the main results from Sulpis et al. (PNAS, 2018). All the variables have a 1x1 degree resolution. It can be used to compute calcite dissolution at the seafloor for changing bottom-water chemistry, calcite rain rates or current speeds, for instance. Oceanic uptake of anthropogenic CO2 leads to decreased pH, carbonate ion concentration, and saturation state with respect to CaCO3 minerals, causing increased dissolution of these minerals at the deep seafloor. This additional dissolution will figure prominently in the neutralization of man-made CO2. Yet, there has been no concerted assessment of the current extent of anthropogenic CaCO3 dissolution at the deep seafloor. Here, recent databases of bottom-water chemistry, benthic currents, and CaCO3 content of deep-sea sediments are combined with a new rate model to derive the global distribution of benthic calcite dissolution rates and obtain primary confirmation of an anthropogenic component. By comparing pre-industrial with present-day rates, we determine that significant anthropogenic dissolution now occurs in the western North Atlantic, amounting to 40-100% of the total seafloor dissolution at its most intense locations. At these locations, the calcite compensation depth has risen ~300 m. Increased benthic dissolution was also revealed at various hot spots in the southern extent of the Atlantic, Indian and Pacific Oceans. Our findings place constraints on future predictions of ocean acidification, are consequential to the fate of benthic calcifiers, and indicate that a by-product of human activities is currently altering the geological record of the deep sea.