Coccolithophores are calcifying protists that have a significant role in marine biological pump through calcite production (CP). We determined the biological calcification rate and ecologically key species (e.g., Gephyrocapsa oceanica ) contribution to total calcite stocks in the eastern Indian Ocean (EIO) during spring intermonsoon; this region was quite undersampled compared to other oceanic regions. Our results indicated that the numerically dominant species are of great importance to cell calcite even with low cellular calcite. CP rate in EIO ranged from 0.148 to 85.017 μmol C·m⁻³·day⁻¹ in the entire data set, which was lower than those in the global ocean. Coccolithophores contributed 8.5% of total phytoplankton carbon fixation. CP acted as a function of light irradiance in the euphotic zone, while a decoupling between CP and primary productivity was found in most of the bottom of euphotic zone. To some degree, this decoupling indicated calcification was more nitrate dependent and less light dependent than photosynthesis. CP/primary productivity ratios were highly variable in our database and were possibly influenced by photoacclimation across various coccolithophore species. As roughly estimated, the turnover rate of coccolith calcite took values around 0.02–0.05 day⁻¹. The association between particulate organic carbon and calcite stocks implied a potential increasing ballast as depth increase. The current profiles of calcification and associated biogeochemical elements obtained from this field study helps our understanding about characteristics of biological pump in the EIO and are valuable for estimating calcification rate in the region using satellite data and numerical modeling.

中文翻译：

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东印度洋的球石珊瑚生物钙化率和物种特异性贡献对方解石总库存的影响

球墨石化钙化生物，通过方解石生产（CP）在海洋生物泵中起重要作用。我们确定了春季季风期间印度洋东部（EIO）的生物钙化率和生态关键物种（例如，Gephyrocapsa oceanica）对方解石总储量的贡献；与其他海洋区域相比，该区域的采样率相当低。我们的结果表明，即使孔道方解石含量低，数值上占优势的物种对方解石也非常重要。EIO中的CP速率介于0.148至85.017μmolC·m ^-3 ·day ^-1整个数据集中的数据低于全球海洋中的数据。球隐藻对总浮游植物固碳的贡献为8.5％。磷在富营养区的作用是光辐照度的函数，而富磷区的大部分底部则发现磷与初级生产力之间存在脱钩。在某种程度上，这种脱钩表明钙化比光合作用对硝酸盐的依赖性更大，对光的依赖性更小。CP /初级生产力比在我们的数据库中是高度可变的，并且可能受各种球石藻物种的光驯化的影响。粗略估计，可可石方解石的周转率约为0.02–0.05天^-1。颗粒有机碳和方解石储量之间的联系意味着随着深度的增加，压载物的潜在增加。从该现场研究中获得的钙化作用及其相关生物地球化学元素的当前概况有助于我们了解EIO中生物泵的特征，对于利用卫星数据和数值模型估算该地区的钙化率具有重要价值。