Large Contribution of Pteropods to Shallow CaCO3 Export

Erik Buitenhuis, Corinne Le Quere, Nina Bednarsek, Ralf Schiebel

Research output: Contribution to journalArticlepeer-review

22 Citations (Scopus)
19 Downloads (Pure)

Abstract

The literature on the relative contributions of pelagic calcifying taxa to the global ocean export of CaCO3 is divided. Studies based on deep sediment trap data tend to argue that either foraminifers or coccolithophores, both calcite producers, dominate export. However, the compilations of biomass observations for pteropods, coccolithophores, and foraminifers instead show that pteropods dominate the global ocean calcifier biomass and therefore likely also carbonate export. Here we present a new global ocean biogeochemical model that explicitly represents these three groups of pelagic calcifiers. We synthesize databases of the physiology of the three groups to parameterize the model and then tune the unconstrained parameters to reproduce the observations of calcifier biomass and CaCO3 export. The model can reproduce both these observational databases; however, substantial dissolution of aragonite above the aragonite saturation horizon is required to do so. We estimate a contribution of pteropods to shallow (100 m) export of CaCO3 of at least 33% and to pelagic calcification of up to 89%. The high production‐high dissolution configuration that shows closest agreement with all the observations has a CaCO3 production of 4.7 Pg C/year but CaCO3 export at 100 m of only 0.6 Pg C/year.
Original languageEnglish
Pages (from-to)458-468
JournalGlobal Biogeochemical Cycles
Volume33
Issue number3
Early online date23 Feb 2019
DOIs
Publication statusPublished - Mar 2019

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