Belevich Tatiana A, Milyutina Irina A, Demidov Andrey B, Vorob'eva Olga V, Polukhin Alexander A, Shchuka Sergey A, Troitsky Aleksey V
Biological Faculty, Lomonosov Moscow State University, 119234 Moscow, Russia.
Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia.
Plants (Basel). 2025 Aug 22;14(17):2614. doi: 10.3390/plants14172614.
Increased Atlantic water transport and river discharge are more pronounced effects of global warming at high latitudes. Both phenomena may lead to changes in the species composition of small-celled algae populations in marine ecosystems, as well as to the emergence of new species. This study investigated the spatial distribution of picocyanobacterial (PC) abundance and the phylogenetic diversity of PC in the Kara Sea. PC abundance varied from 2 to 88 cells mL and increased with warming temperatures and decreasing salinity caused by river water influence. The contribution of to the total picophytoplankton biomass was low (<16%). The community was characterized at deep taxonomic level using amplicon sequencing targeting the gene. Diversity was low, revealing only subcluster 5.1 polar lineages I and IV, and euryhaline subcluster 5.2. subcluster 5.1.I represented on average 97% of the total reads assigned to cyanobacteria. For the first time, the presence of estuarine subcluster 5.2 was documented as far north as 82° N. Modified Atlantic water was the main source of cyanobacteria in the Kara Sea, followed by river discharge. Our study contributes to the understanding of PC sources in the Kara Sea and allows for the further monitoring of PC distribution and evolution.
北大西洋水体输送增加和河流径流量增加是全球变暖在高纬度地区更为显著的影响。这两种现象都可能导致海洋生态系统中小细胞藻类种群的物种组成发生变化，以及新物种的出现。本研究调查了喀拉海微微型蓝细菌（PC）丰度的空间分布及其系统发育多样性。PC丰度在2至88个细胞/毫升之间变化，并随着水温升高和河水影响导致的盐度降低而增加。其对总微微型浮游植物生物量的贡献较低（<16%）。利用靶向 基因的扩增子测序在深度分类水平上对PC群落进行了表征。多样性较低，仅揭示了5.1亚簇极地谱系I和IV以及广盐性5.2亚簇。5.1.I亚簇平均占分配给蓝细菌的总读数的97%。首次记录到河口5.2亚簇在北纬82°以北的存在。经改造的北大西洋水体是喀拉海蓝细菌的主要来源，其次是河流径流。我们的研究有助于了解喀拉海PC的来源，并有助于进一步监测PC的分布和演化。
