Spatial variations in the phytoplankton community compositions, carbon dioxide system and ancillary water column properties, were monitored across various frontal systems in the Indian Sector of Southern Ocean (ISSO) during austral summer 2013. Four major frontal systems, namely, the Agulhas Return Front (ARF), Southern Subtropical Front (SSTF), Subantarctic Front (SAF) and Polar Front (PF) were identified along the study area. Major groups of phytoplankton were distinguished adopting single marker pigment approach. Statistical computations showed the distribution of diatoms were influenced by the availability of inorganic nutrients (primarily silicate and nitrate) and mixed layer depths (MLD). Haptophytes were strongly dependent on phosphate availability, whereas, picoplankton flourished in water where regenerated nutrient ammonium was present. The lowest surface pCO₂ (267.26–291.5 µatm) along with in situ oxygen production (> 10 µM) was encountered at the two warmer fronts, ARF and SSTF, dominated by haptophytes and picoplankton. The colder Antarctic fronts, SAF and PF were dominated by diatoms where surface pCO₂ was relatively higher (> 350µatm). Poor statistical correlation among temperature and total chlorophyll with pCO₂ revealed complex interplay of multiple factors. Contribution of major phytoplankton groups towards pCO₂ drawdown was computed using a one-dimensional model describing the relative contributions of biological activities. In ISSO, calcifying and photosynthesizing haptophytes were observed to play a crucial role in the “biological pump” of CO₂ drawdown at ARF, SSTF and SAF, while the silicifying micro phytoplankton diatoms and picoplankton were more effective at PF.

2013 年南方夏季期间，在南大洋印度区 (ISSO) 的各个锋面系统中监测了浮游植物群落组成、二氧化碳系统和辅助水柱特性的空间变化。 四个主要锋面系统，即厄加勒斯回流锋（ ARF)、南亚热带锋 (SSTF)、亚南极锋 (SAF) 和极地锋 (PF) 沿研究区被确定。采用单一标记色素法区分主要浮游植物群。统计计算表明，硅藻的分布受无机养分（主要是硅酸盐和硝酸盐）和混合层深度（MLD）的影响。触生植物强烈依赖于磷酸盐的可用性，而微型浮游生物在存在再生营养铵的水中繁衍生息。₂ (267.26–291.5 µatm) 以及原位氧气产生 (> 10 µM) 在两个较暖的锋面 ARF 和 SSTF 中遇到，这些锋面以触藻和微型浮游生物为主。较冷的南极锋、SAF 和 PF 以硅藻为主，其中表面 pCO ₂相对较高（> 350µatm）。温度和总叶绿素与 pCO ₂之间的不良统计相关性揭示了多种因素的复杂相互作用。主要浮游植物群对 pCO ₂下降的贡献是使用描述生物活动相对贡献的一维模型计算的。在ISSO中，观察到钙化和光合作用的触生植物在CO ₂的“生物泵”中起着至关重要的作用 ARF、SSTF 和 SAF 的水位下降，而硅化微型浮游植物硅藻和微型浮游生物在 PF 中更有效。