第八届青年地学论坛

We presented carbonate data collected during July and September 2018 to investigate the spatiotemporal distributions of sea surface partial pressure of CO₂ (pCO₂), CO₂ flux and their controls during warm seasons in the Bering Sea. In different geographic regions, the observed seawater pCO₂ in both months varied within a wide range of ~178-361 µatm, which was much lower than the overlying atmospheric CO₂, suggesting a net CO₂ sink with fluxes of -4.4 and -7.3 mmol m^-2 d^-1 in July and September, respectively. In the Bering Strait and the Shelf, low DIC (~1756-1991 µmol kg^-1) and pCO₂ (~178-278 µatm) were observed in the coastal plume water and the shelf water with a biological DIC drawdown of ~54.2 µmol kg^-1 and ~32.3-59.1 µmol kg^-1, respectively. In contrast, much higher values were observed in a coastal upwelling system of Bering Strait with ~2055 µmol kg^-1 for DIC and ~344 µatm for pCO₂. In terms of temporal variability, pCO₂ on the offshore shelf increased from ~244 µatm in July to ~278 µatm in September, which was mainly controlled by the joint influence of the intrusion of Ice-Melt Water (IMW) and the decreased DIC biological uptake. In the Bering Sea Basin and the Slope, pCO₂ was much higher than the shelf water with moderate temporal variabilities. The decreased pCO₂ from ~351-360 µatm in July to ~280-317 µatm in September was mainly controlled by the two end-member mixing of different water masses with negligible influence of biological uptake and temperature effect.
 

Bering Sea,partial pressure of CO2 (pCO2),spatial variability,temporal dynamics,air-sea CO2 flux,controlling processes