Carbonate System And Air-sea CO2Fluxes In Prydz Bay, The Antarctica

The carbon cycle in the polar ocean changed greatly under the global change.Prydz Bay is a typical area of ocean carbon research in the Sourthern Ocean. It is thethird bay among the bays around the Antarctic continent. Sea ice processes, biologicalprocess, hydrological process and the coupling by them made the control mechanismof carbon cycle complication in Prydz Bay. It is also a key research area in ChineseNational Antarctic Research Expedition (CHINARE). In2008~2009and2009~2010,the25th and the26th CHINARE implemented, obtained a lot of valuable data, whichis bound up with the ocean carbon cycle. We comprehensively described thecarbonate systemcharacteristics in Prydz Bay by total alkalinity (TA), total dissolvedinorganic carbon (DIC), CO2partial pressure (pCO2), pH and calculated the air-seaCO2flux, net community productivity (NCP), Revelle factor. On the base of theseresults, we evaluated the CO2sink of Prydz Bay and discussed their controlmechanism.Prydz Bay is a area of CO2strong sink and the air-sea CO2flux is-34.5mmolm-2d-1. According to the variations of pCO2, Prydz Bay could be divided into theinside and outside regions by the boundary of66°S. The inside area has a low pCO2(220.3atm) and a strong air-sea CO2flux (-41.4mmol m-2d-1). The inside area hasa high pCO2(350.0atm) and a strong air-sea CO2flux (-6.1mmol m-2d-1). Duringthe underway monitoring in Prydz Bay in the sunmer of2009~2010, the Spatial andtemporal variations of pCO2are significant difference. In December2009, the pCO2is220.8atm and the air-sea CO2flux is-41.4mmol m-2d-1. In February2010, thepCO2is273.3atm and the air-sea CO2flux is-26.9mmol m-2d-1. In summary, thestrength of CO2is mainly controlled by the biological production. In the inside of thebay, phytoplankton assimilate the DIC greatly and reduces the pCO2; in the outside ofthe bay, the hydrological processes become the mainly controlled factors, the highCO2subsurface water upwelling in the Antarctic Divergence (AD) and affected the carbon cycle characteristics of near area.In the centre of Prydz Bay near73°E the carbon cycle characteristics areobviously. In December2009, the variations of pCO2in this area are: shelf area (southof67.5°S,162.2atm)<slope area (67.5~66°S,240.2atm)<south of the AD(66-64.5°S,353.5atm) north of the AD (64-62°S,351.0atm)<the centre of AD(64.5-64°S,369.4atm) and the variations of air-sea CO2flux are: shelf area (southof67.5°S,-54.5mmol m-2d-1)> slope area (67.5~66°S,-34.2mmol m-2d-1)> southof the AD (66-64.5°S,-4.8mmol m-2d-1) north of the AD (64-62°S,3-5.4mmol m-2d-1)> the centre of AD (64.5-64°S,-0.6mmol m-2d-1).In summer2009~2010, the surface pH of Prydz Bay is7.978far lower than theaverage of global ocean and shows a variation: shelf area> slope area> the deepocean of the outside bay. The R50(average of buffer factors at top of the water columabove the50m layer) of Prydz Bay is19.2far higher the average of the seasonal seaice area of southern ocean and and shows a variation: shelf area <slope area <thedeep ocean of the outside bay. CO2 pH H+1.3~1.6pH DIC TA pCO2...