A survey of marine pelagic coastal microbial communities was conducted over a large geographic latitude range, from Cape Mendocino in northern California USA to Queen Charlotte Sound in British Columbia Canada, during the spring to summer transition. DNA metabarcoding and flow cytometry were used to characterize microbial communities. Physical and chemical oceanography indicated moderate conditions during the survey with no widespread upwelling, marine heat wave, or other extreme conditions. However, four locations displayed features approaching acidified conditions: Heceta Head, Newport, Copalis Beach, and Cape Flattery. Although bacterial and archaeal communities at the Juan de Fuca canyon and northward had high similarity, those south of the Juan de Fuca canyon were well differentiated from each other. In contrast, eukaryotic microbial communities exhibited stronger geographic differentiation than bacterial and archaeal communities across the extent of the survey. Seawater parameters that were best predictors of bacterial and archaeal community structure were temperature, pH, and dissolved inorganic nutrients (nitrate, phosphate, silicate), while those that were best predictors of eukaryotic microbial community structure were salinity, dissolved oxygen, total alkalinity, and dissolved inorganic nutrients (nitrite, silicate). Although five bacterial and archaeal indicators for potentially corrosive waters were identified (Colwellia, Nitrosopumilus, Nitrosopelagicus, Sup05 cluster, Sva0996 marine group), no eukaryotic microbial indicators were found. Potentially pathogenic taxa detected in the survey included four disease-causing bacteria for mammals, finfish, and/or shellfish (Coxiella, Flavobacterium, Francisella, Tenacibaculum), sixteen genera of microalgae capable of producing biotoxins, and fifteen parasitic species. This study demonstrates the value of coordinating microbial sampling and analysis with broad-scale oceanographic surveys to generate insights into community structures of these important pelagic trophic levels.

中文翻译：

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加拿大和美国太平洋西北海岸的近岸微生物群落


在春季到夏季的过渡期间，对从美国加利福尼亚州北部门多西诺角到加拿大不列颠哥伦比亚省夏洛特皇后湾的大地理纬度范围内的海洋中上层沿海微生物群落进行了调查。 DNA 元条形码和流式细胞术用于表征微生物群落。物理和化学海洋学显示调查期间条件温和，没有大范围的上升流、海洋热浪或其他极端条件。然而，有四个地点显示出接近酸化条件的特征：赫塞塔角、纽波特、科帕利斯海滩和弗拉特里角。尽管胡安德富卡峡谷及其北部的细菌和古菌群落具有很高的相似性，但胡安德富卡峡谷以南的细菌和古菌群落彼此之间存在很大差异。相比之下，在整个调查范围内，真核微生物群落表现出比细菌和古菌群落更强的地理分化。细菌和古菌群落结构的最佳预测因子是温度、pH 值和溶解的无机营养物（硝酸盐、磷酸盐、硅酸盐），而真核微生物群落结构的最佳预测因子是盐度、溶解氧、总碱度和溶解度。溶解的无机营养物（亚硝酸盐、硅酸盐）。尽管鉴定出五种潜在腐蚀性水体的细菌和古菌指标（Colwellia、Nitrosopumilus、Nitrosopelagicus、Sup05 簇、Sva0996 海洋群），但没有发现真核微生物指标。 调查中检测到的潜在致病类群包括四种对哺乳动物、有鳍鱼类和/或贝类致病的细菌（柯克斯菌属、黄杆菌属、弗朗西斯菌属、粘杆菌属）、十六种能够产生生物毒素的微藻和十五种寄生物种。这项研究证明了将微生物采样和分析与大规模海洋学调查相协调的价值，以深入了解这些重要的中上层营养级的群落结构。