New in situ estimates of carbon biological production rates in the Southern Ocean from CARIOCA drifter measurements

Abstract

A CARbon Interface OCean Atmosphere (CARIOCA) surface buoy drifted from 2006 to 2007 in the polar regions of the South Atlantic and Indian Oceans. Derived values of the surface dissolved inorganic carbon (DIC) displayed conspicuous daily variations with a close to sunrise maximum and a close to sunset minimum. This decrease of carbon is a measurement of the Net Community Production (NCP) during daytime at 2 meters depth. NCP integrated over the mixed layer is computed from the daily change of the maxima of DIC. When combined with mixed layer depths estimated from Argo floats, we find that north of South Georgia Island, NCP ranges from 82 to 118 mmol m−2 d−1 in the fall and from 30 to 51 mmol m−2 d−1 close to 17°W in late spring. This study highlights the possibility of estimating biological carbon production rates by an in situ non‐intrusive method from unattended platforms.