Hot Spots of Carbon and Alkalinity Cycling in the Coastal Oceans

Ocean calcium carbonate (CaCO(3)) production and preservation play a key role in the global carbon cycle. Coastal and continental shelf (neritic) environments account for more than half of global CaCO(3) accumulation. Previous neritic CaCO(3) budgets have been limited in both spatial resolution and ability to project responses to environmental change. Here, a 1° spatially explicit budget for neritic CaCO(3) accumulation is developed. Globally gridded satellite and benthic community area data are used to estimate community CaCO(3) production. Accumulation rates (PgC yr(−1)) of four neritic environments are calculated: coral reefs/banks (0.084), seagrass-dominated embayments (0.043), and carbonate rich (0.037) and poor (0.0002) shelves. This analysis refines previous neritic CaCO(3) accumulation estimates (~0.16) and shows almost all coastal carbonate accumulation occurs in the tropics, >50% of coral reef accumulation occurs in the Western Pacific Ocean, and 80% of coral reef, 63% of carbonate shelf, and 58% of bay accumulation occur within three global carbonate hot spots: the Western Pacific Ocean, Eastern Indian Ocean, and Caribbean Sea. These algorithms are amenable for incorporation into Earth System Models that represent open ocean pelagic CaCO(3) production and deep-sea preservation and assess impacts and feedbacks of environmental change.