We studied time-series fluxes of radiolarian particles collected by two sediment traps deployed at the eastern (Sta. NAP12t) and western (Sta. CAP12t) sides of the Chukchi Borderland in the Chukchi Sea from 04 October 2012 to 18 September 2013. In order to elucidate the contribution of radiolarian skeletons to the biogenic silica flux, a three-dimensional (3D) imaging technique using microfocus X-ray computed tomography (MXCT) was applied to radiolarian siliceous skeletons. We calculated volumes of individual radiolarian skeletons accurately using a 3D model of them, thereby estimating the mass of silica for each radiolarian species. The time-series fluxes of radiolarian abundance were combined with the mass of radiolarian silica and were transformed to estimate fluxes of radiolarian silica. As a result, we found that the main carrier of radiolarian silica in the western Arctic Ocean was represented by only two species; that is, Amphimelissa setosa (averages: 55.2 wt% at Sta. NAP12t, 70.8 wt% at Sta. CAP12t) and Spongotrochus glacialis (averages: 36.7 wt% at Sta. NAP12t, 23.2 wt% at Sta. CAP12t). The total radiolarian silica flux was usually higher in the eastern side than that in the western side of the Chukchi Borderland. The contribution of radiolarian silica to the biogenic silica flux was less than 10 wt% in general during the sampling duration, but occasionally reached 19.6–34.8 wt% during the open water season. This suggests that not only diatoms but also radiolarians make a significant contribution in driving the silica cycle in the Arctic Ocean.

中文翻译：

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使用微焦点 X 射线计算机断层扫描对北冰洋西部放射虫（根瘤菌）物种特异性生物二氧化硅通量的新评估

我们研究了 2012 年 10 月 4 日至 2013 年 9 月 18 日在楚科奇海楚科奇边境东部 (Sta. NAP12t) 和西部 (Sta. CAP12t) 部署的两个沉积物捕集器收集的放射虫粒子的时间序列通量。为了阐明放射虫骨骼对生物二氧化硅通量的贡献，将使用微焦点 X 射线计算机断层扫描 (MXCT) 的三维 (3D) 成像技术应用于放射虫硅质骨骼。我们使用它们的 3D 模型准确计算了单个放射虫骨骼的体积，从而估计了每个放射虫物种的二氧化硅质量。放射虫丰度的时间序列通量与放射虫二氧化硅的质量相结合，并被转换为估计放射虫二氧化硅的通量。其结果，我们发现北冰洋西部放射虫二氧化硅的主要载体只有两种；那是，Amphimelissa setosa（平均：Sta. NAP12t 的 55.2 wt%，Sta. CAP12t 的 70.8 wt%）和 Spongotrochus glacialis（平均：Sta. NAP12t 的 36.7 wt%，Sta. CAP12t 的 23.2 wt%）。楚科奇边疆区东部的放射虫二氧化硅总通量通常高于西部。在采样期间，放射虫二氧化硅对生物二氧化硅通量的贡献通常小于 10 wt%，但在开放水域季节偶尔会达到 19.6-34.8 wt%。这表明不仅硅藻而且放射虫也对推动北冰洋的二氧化硅循环做出了重大贡献。