Siliceous polycystines and phaeodarians are open-ocean planktonic protists found throughout the water column and characterized by complex siliceous skeletons that are formed, at least partly, through the uptake of silicic acid. These protists contribute to the marine organic carbon (C) and biogenic silica (bSi) pools, but little is known about their contribution to the silica (Si) biogeochemical cycle. Here we report the first measurements of the Si uptake rate of polycystine and phaeodarian cells from samples collected in the Mediterranean Sea using the 32 Si-based method. The elementary composition (bSi, particulate organic carbon and nitrogen) of these organisms was also measured. Combining our results with published data on the distribution and abundance of Polycystina and Phaeodaria in the global ocean, we conclude that these organisms could contribute from 0.2 to 2.2 mmol Si m −2 of the marine standing stock of bSi and from 2 to 58 Tmol Si yr −1 (1% to 19%) of the global oceanic biogenic silica production. The implications for the global marine Si cycle are discussed.

中文翻译：

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估计全球海洋中根茎的生物二氧化硅产量

硅质多囊藻类和 phaeodarians 是在整个水体中发现的开阔海洋浮游原生生物，其特征是复杂的硅质骨架，至少部分是通过摄取硅酸形成的。这些原生生物对海洋有机碳 (C) 和生物二氧化硅 (bSi) 池有贡献，但对它们对二氧化硅 (Si) 生物地球化学循环的贡献知之甚少。在这里，我们报告了使用基于 32 Si 的方法在地中海收集的样本中对多胱氨酸和 phaeodarian 细胞的 Si 吸收率的首次测量。还测量了这些生物的元素组成（bSi、颗粒有机碳和氮）。将我们的结果与已发表的关于全球海洋中多囊藻和褐藻分布和丰度的数据相结合，我们得出的结论是，这些生物可以贡献 0.2 到 2.2 mmol Si m -2 的 bSi 海洋常备库存和 2 到 58 Tmol Si yr -1（1% 到 19%）的全球海洋生物二氧化硅产量。讨论了对全球海洋硅循环的影响。