The Pacific Arctic region is characterized by seasonal sea-ice, the spatial extent and duration of which varies considerably. In this region, diatoms are the dominant phytoplankton group during spring and summer. To facilitate survival during periods that are less favorable for growth, many diatom species produce resting stages that settle to the seafloor and can serve as a potential inoculum for subsequent blooms. Since diatom assemblage composition is closely related to sea-ice dynamics, detailed studies of biophysical interactions are fundamental to understanding the lower trophic levels of ecosystems in the Pacific Arctic. One way to explore this relationship is by comparing the distribution and abundance of diatom resting stages with patterns of sea-ice coverage. In this study, we quantified viable diatom resting stages in sediments collected during summer and autumn 2018 and explored their relationship to sea-ice extent during the previous winter and spring. Diatom assemblages were clearly dependent on the variable timing of the sea-ice retreat and accompanying light conditions. In areas where sea-ice retreated earlier, open-water species such as Chaetoceros spp. and Thalassiosira spp. were abundant. In contrast, proportional abundances of Attheya spp. and pennate diatom species that are commonly observed in sea-ice were higher in areas where diatoms experienced higher light levels and longer day length in/under the sea-ice. This study demonstrates that sea-ice dynamics are an important determinant of diatom species composition and distribution in the Pacific Arctic region.

中文翻译：

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海冰动力学对太平洋北极地区沉积物中硅藻静止期空间分布的影响

太平洋北极地区以季节性海冰为特征，其空间范围和持续时间差异很大。在该地区，硅藻是春季和夏季的主要浮游植物群。为了在不利于生长的时期生存，许多硅藻物种会产生沉睡阶段，这些阶段会沉入海底，并可以作为后续藻华的潜在接种物。由于硅藻组合组成与海冰动力学密切相关，因此对生物物理相互作用的详细研究对于了解太平洋北极生态系统的较低营养水平至关重要。探索这种关系的一种方法是将硅藻休眠阶段的分布和丰度与海冰覆盖模式进行比较。在这项研究中，我们量化了 2018 年夏季和秋季收集的沉积物中有活力的硅藻休眠阶段，并探讨了它们与前一个冬季和春季期间海冰范围的关系。硅藻组合显然取决于海冰退缩的可变时间和伴随的光照条件。在海冰较早退缩的地区，开放水域的物种如角角藻属 和Thalassiosira属。很丰富。相比之下，Attheya spp 的比例丰度。海冰中常见的羽状硅藻物种在海冰中/下的硅藻光照水平较高和日照时间较长的地区较高。这项研究表明，海冰动力学是太平洋北极地区硅藻物种组成和分布的重要决定因素。