Global net CaCO3 export production estimated from the surface water total alkalinity change using Argo profiling data

Abstract

Global net CaCO3 export production can be determined from the decrease in salinity (S)-normalized total alkalinity (NA_T = A_T × 35/S) in the surface mixed layer. A_T has correlations with sea surface temperature (SST) and salinity (SSS), thus it can be calculated from region-specific algorithms derived from simple functions of SST and SSS in the form. Argo is broad-scale global array of temperature and salinity profiling floats and produces real time temperature and salinity profile data. Using Argo’s temperature and salinity data, global net CaCO3 export production can be estimated from the seasonal changes in NA_T based on modeling. CaCO3 export mechanism is important to looking how much carbon from the atmosphere is uptake into the ocean by calcifier annually. This study covers 10 years (2003 to 2012) annual global net CaCO3 export production. The annual global net CaCO3 export production is 0.84 ± 0.3 Gt C yr^(-1) in 2003 - 2012. Large variation from 2008 and 2009, these estimates are certainly high because La Niña condition leads lower SST in tropical Pacific Ocean and higher NA_T in early 2008 and 2009. Except the export value of 2008 and 2009, global net CaCO3 export production is 0.71 ± 0.2 Gt C yr^(-1).