title: Contribution of fish to the marine inorganic carbon cycle.
abstract: Oceanic production of calcium carbonate is conventionally attributed to marine plankton (coccolithophores and foraminifera). Here we report that marine fish produce precipitated carbonates within their intestines and excrete these at high rates. When combined with estimates of global fish biomass, this suggests that marine fish contribute 3 to 15% of total oceanic carbonate production. Fish carbonates have a higher magnesium content and solubility than traditional sources, yielding faster dissolution with depth. This may explain up to a quarter of the increase in titratable alkalinity within 1000 meters of the ocean surface, a controversial phenomenon that has puzzled oceanographers for decades. We also predict that fish carbonate production may rise in response to future environmental changes in carbon dioxide, and thus become an increasingly important component of the inorganic carbon cycle.
authors.affiliation: School of Biosciences, University of Exeter, Exeter EX4 4PS, UK. r.w.wilson@ex.ac.uk
authors.forename: R W
authors.initials: RW
authors.lastname: Wilson
authors.forename: F J
authors.initials: FJ
authors.lastname: Millero
authors.forename: J R
authors.initials: JR
authors.lastname: Taylor
authors.forename: P J
authors.initials: PJ
authors.lastname: Walsh
authors.forename: V
authors.initials: V
authors.lastname: Christensen
authors.forename: S
authors.initials: S
authors.lastname: Jennings
authors.forename: M
authors.initials: M
authors.lastname: Grosell
mesh_terms: D000818:Animals; D018533:Biomass; D002113:Calcification, Physiologic; D002119:Calcium Carbonate / Q000737:chemistry / Q000378:metabolism*; D002244:Carbon / Q000737:chemistry; D002245:Carbon Dioxide / Q000097:blood; D011232:Chemical Precipitation; D017753:Ecosystem; D005399:Fishes / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007413:Intestinal Mucosa / Q000378:metabolism*; D009792:Oceans and Seas; D010933:Plankton / Q000502:physiology; D012623:Seawater / Q000737:chemistry*; D012995:Solubility; D013696:Temperature
chemical_list: D002245:Carbon Dioxide; D002244:Carbon; D002119:Calcium Carbonate