PHYSIOLOGICAL AND ECOSYSTEM STRUCTURE FORCINGS ON CARBON FLUXES IN THE SOUTHERN OCEAN MIXED LAYER

根据正在进行的对表层海水样品中溶解O2/Ar比率和氧的三同位素（16O,17O, 18O）组成的测量，将在帕尔默站附近LTER研究区域的巡航上确定两种非孵育生物地球化学指标的估计值。通过O2/Ar比可以测量生物产生的氧过饱和度。溶解氧的一个单独的三重同位素测定得到了浮游植物光合作用产生的溶解氧池的部分。随着氧气交换系数的知识，可以估计混合层的净群落生产量（NCP）和总初级生产量（GPP）。其他生物地球化学参数，如营养物质、光、中尺度变异性、脉冲幅度荧光（浮游植物生理应激的指示）、浮游生物分类（HPLC色素；卫星图像）以及颗粒有机碳可用于解释和合成生物生产力术语。对南大洋氧循环的研究可以建立一个对碳循环的补充观点，原则上可以作为对全球海洋这一重要的二氧化碳汇区碳预算项的独立检查。其次，通过研究净群落生产指标与南大洋浮游生物群落组合之间的关系，可以揭示南大洋生态系统变化的潜力。

Based on underway measurements of the dissolved O2/Ar ratio and the triple isotopic (16O,17O, 18O) composition of oxygen in surface seawater samples, estimates of two non-incubation biogeochemical proxies are to be determined on cruises in the LTER study region adjacent to Palmer Station. A measure of biological produced oxygen super-saturation can be made from the O2/Ar ratio. A separate triple isotopic determination of dissolved oxygen yields the fraction of the dissolved oxygen pool derived from phytoplankton photosynthesis. Along with a knowledge of the oxygen gas exchange coefficient, rates of net community production (NCP) and gross primary production (GPP) in the mixed layer can be estimated. Other biogeochemical parameters such as nutrients, light, mesoscale variability, pulse amplitude fluorescence (indication of phytoplankton physiological stress), plankton taxonomy (HPLC pigments; satellite imagery), along with particulate organic carbon may be used to interpret and synthesize the biological productivity terms. Study of the Southern Ocean oxygen cycle allows a complementary view of the carbon cycle to be constructed, and in principle may serve as an independent check of the carbon budget terms in this important CO2 sink region of the global ocean. Secondly, the potential for ecosystem change may also be revealed from study of the relationships between proxies of net community production and the assemblage of Southern Ocean plankton communities.