Net removal of major marine dissolved organic carbon fractions in the subsurface ocean

作者：Hansell Dennis A^*; Carlson Craig A; Schlitzer Reiner

来源：Global Biogeochemical Cycles, 2012, 26(1): GB1016.

DOI：10.1029/2011GB004069

Marine dissolved organic matter is a massive reservoir of carbon holding %26gt;200x the ocean biomass inventory. Primarily produced at the ocean surface and then exported to depth with overturn of the water column, this carbon can be sequestered in the ocean interior for centuries. Understanding the loss of dissolved organic carbon (DOC) upon export has been data limited, but recent global ocean surveys are overcoming that problem. Here we characterize three fractions of exported carbon by apparent continuity in removal rates: semi-labile and semi-refractory, summing to 20 PgC, and the balance as refractory DOC. Distinct lifetimes coupled with ocean circulation control where the fractions are exported to depth, and thus the carbon sequestration time scales. Maximum remineralization rates of exported DOC occur in the convergent subtropical gyres, where a range of similar to 500 to %26lt;1500 mmol C m(-2) yr(-1) can exceed remineralization of sinking biogenic particles. Regions of high particle export production and highly stratified systems exhibit minimal exported DOC remineralization.

• 出版日期2012-2-4