Abstract：
The Laptev Sea is a major Marginal Sea in the Western Arctic Ocean. The Arctic amplification brought by global warming influences the hydrological properties of rivers passing through the permafrost zone, which would alter the biological community structure at continental margin. In this study, the structure, assembly, and gene expression of planktonic microbial communities in two estuaries (Protoka Ularovskaya River Estuary, PURE; Lena River Estuary, LRE) of Laptev Sea were examined to investigate the environmental effects of polar rivers. PURE and LRE exhibited distinct environmental characteristics: low temperature and high salinity for PURE, and high temperature and low salinity for LRE, influenced by runoff size. Salinity more closely influenced microbial communities in LRE, with freshwater species playing a significant role in community composition. The findings revealed differences between two estuaries in community composition and diversity. Prokaryotes and microeukaryotes had shown different assembly patterns in response to habitat changes caused by terrestrial freshwater input. Furthermore, compared with the PURE, the co-occurrence and inter-domain network of the LRE, which was more affected by terrestrial input, was more complex and stable. Functional gene prediction revealed a higher gene expression of methane metabolism in LRE than in PURE, particularly those related to methane oxidation, and this conclusion could help better explore the impact of global warming on the methane cycle in the Arctic Marginal Seas. This study explored the increased freshwater runoffs under the background of global warming dramatically affect Arctic microplankton communities from community structure, assembly and gene expression aspects.
摘要：
拉普捷夫海是北冰洋西部的主要边缘海。全球变暖带来的北极放大影响了通过多年冻土带的河流的水文特性，这将改变大陆边缘的生物群落结构。在这项研究中,结构,装配,和两个河口浮游微生物群落的基因表达(ProtokaUlarovskaya河口，纯净；莉娜河口，LRE）对拉普捷夫海进行了检查，以调查极地河流的环境影响。PURE和LRE表现出独特的环境特征：PURE的低温和高盐度，LRE的高温和低盐度，受径流大小的影响。盐度更密切地影响LRE中的微生物群落，淡水物种在群落组成中起着重要作用。研究结果表明，两个河口在群落组成和多样性方面存在差异。原核生物和微真核生物对陆地淡水输入引起的栖息地变化表现出不同的组装模式。此外，与PURE相比，LRE的共现和域间网络，受地面输入的影响更大，更加复杂和稳定。功能基因预测显示LRE中甲烷代谢的基因表达高于PURE，特别是那些与甲烷氧化有关的，这一结论有助于更好地探讨全球变暖对北极边缘海域甲烷循环的影响。本研究从群落结构上探讨了全球变暖背景下淡水径流增加对北极微浮游生物群落的影响,组装和基因表达方面。
