To investigate the spatial distributions and determinants of nutrient concentrations, we measured NO+NO, PO, and Si(OH) concentrations in the eastern Indian Ocean sector of the Antarctic Ocean (80 − 150°E, south of 60°S) between December 2018 and February 2019. In the region influenced by the Antarctic Circumpolar Current, nutrient concentrations were increased by nutrients supplied from the deep layer and by organic matter decomposition and remineralization within the seasonal pycnocline after the development of strong stratification. Strong stratification also enhanced phytoplankton growth and nutrient consumption by photosynthesis. In contrast, in the subpolar region, nutrient concentrations were increased by nutrients supplied by brine discharged during sea ice formation and decreased by dilution with sea ice meltwater. Although high salinity in the surface and subsurface layers corresponded well to upwelling areas around subpolar subgyres, high salinity was not necessarily correlated with nutrient concentrations. We estimated primary production both from in situ nutrient data and from satellite-acquired chlorophyll- data. According to both estimation methods, primary production was high in the subpolar region, especially around 120 − 130°E. However, nutrient-based estimation also showed high production in coastal areas where, because of sea ice and cloud cover, estimation based on satellite data was not possible. To understand primary production in seasonal ice areas, the best estimation method should be selected for the research goals or multiple methods should be used in combination.

中文翻译：

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决定南大洋副极地营养物和初级生产力分布的海洋因素


为了研究营养物浓度的空间分布和决定因素，我们在 12 月间测量了南极洲东印度洋部分（80 – 150°E，60°S 以南）的 NO+NO、PO 和 Si(OH) 浓度2018年和2019年2月。在受南极绕极流影响的区域，由于深层供应的养分以及强烈分层发展后季节性密斜斜内有机物的分解和再矿化，养分浓度增加。强烈的分层还增强了浮游植物的生长和光合作用的营养消耗。相比之下，在副极地地区，养分浓度因海冰形成过程中排放的盐水提供的养分而增加，并因海冰融水的稀释而降低。尽管表层和次表层的高盐度与副极地亚环流周围的上升流区域很好地对应，但高盐度不一定与营养物浓度相关。我们根据原位养分数据和卫星获取的叶绿素数据估算了初级产量。根据这两种估算方法，副极地地区的初级生产力很高，尤其是在 120 − 130°E 附近。然而，基于营养物的估计也显示沿海地区的产量很高，但由于海冰和云层覆盖，无法根据卫星数据进行估计。为了了解季节性冰区的初级产量，应选择适合研究目标的最佳估算方法或多种方法结合使用。