Climate change alters environmental conditions that are expected to have a profound effect on the biodiversity, community composition, and metabolic processes of microeukaryotic plankton in Arctic and Subarctic coastal waters. The molecular biodiversity [large subunit (LSU) rRNA gene] of three plankton size-fractions (micro-, nano-, and picoplankton) from coastal waters of ice-influenced west Greenland was compared with fractions from ice-free northwest Iceland within their summer environmental context. Putative metabolic functions were determined by differentially expressed mRNA (metatranscriptomics) of the microplankton. Temperature and salinity variations were more closely correlated than inorganic macronutrients with metabolic functions and community composition. Temperature explained much of the community variance, approximately 20% among micro- and nanoplankton, whereas other environmental factors accounted for rather low fractional variance (<7%). Species of smaller cell-size were more evenly distributed (Pielou’s evenness index J) across regions, with a higher diversity and total abundance, and thereby indicating high plasticity. The metatranscriptomic profiles in these respective microeukaryotic communities revealed that diatoms were more plastic in their gene expression than dinoflagellates, but dinoflagellates had a more diverse, albeit homogeneously expressed, gene pool. This could be interpreted as expression of alternative lifestyle strategies, whereby the functionally more conservative diatoms fill their niches primarily through variable resource use, whereas dinoflagellates apparently differentiate their niches through more diverse lifestyles. Patterns of microeukaryotic diversity are thus primarily associated with differences in metabolic function and activity of diatom- versus dinoflagellate-dominated communities in Arctic and Subarctic waters during summer.

中文翻译：

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西格陵兰岛和冰岛西北部沿海地表水中微真核生物的比较 Metabarcoding 和 Metatranscriptomic 分析

气候变化改变了环境条件，预计将对北极和亚北极沿海水域微真核浮游生物的生物多样性、群落组成和代谢过程产生深远影响。将来自受冰影响的格陵兰西部沿海水域的三种浮游生物大小部分（微型、纳米和微型浮游生物）的分子生物多样性 [大亚基 (LSU) rRNA 基因] 与夏季期间冰岛西北部无冰的部分进行比较环境背景。假定的代谢功能由微浮游生物的差异表达 mRNA（宏转录组学）确定。温度和盐度的变化比具有代谢功能和群落组成的无机常量营养素更密切相关。温度解释了大部分社区差异，在微型和纳米浮游生物中约为 20%，而其他环境因素占相当低的分数方差（<7%）。细胞尺寸较小的物种在区域间分布更均匀（Pielou 均匀度指数 J），具有更高的多样性和总丰度，从而表明具有较高的可塑性。这些微真核生物群落中的宏转录组学谱显示，硅藻的基因表达比鞭毛藻更具可塑性，但鞭毛藻具有更多样化但表达均匀的基因库。这可以解释为替代生活方式策略的表达，其中功能上更保守的硅藻主要通过可变资源使用来填补它们的生态位，而甲藻显然通过更多样化的生活方式来区分它们的生态位。