Rivers and estuaries along the central Oregon margin transport large amounts of fluvialand terrestrial-derived materials into the coastal ocean during the winter season, which can become trapped in a nearshore coastal current by local density gradients and wind forcing. The influence of these substantial and persistent allochthonous inputs on wintertime biological activity in the Oregon coastal region is not well understood. We compared prokaryotic communities inside and outside of 2 buoyant coastal river plumes off the central Oregon coast in order to understand the relationship between plume conditions and the distributions of prokaryotic populations that form the base of the wintertime coastal food web by transforming carbon and nitrogen compounds. Both free-living and particle-associated communities inside nearshore plume zones were significantly different from communities outside the plume influence. Particulate organic matter concentrations correlated with the distribution of several Bacteroidetes populations with established roles in complex organic matter degradation in coastal ecosystems. Plume conditions also correlated with marine Gammaproteobacteria that are known to degrade terrestrially derived material. Peak heterotrophic respiration rates across sampling stations occurred at a local plume particle maximum, suggesting that particulate resources transported to coastal ocean waters by river plumes may be used or transformed by co-localized heterotrophic microorganisms. Taken together, the associations between river plume resources and prokaryotic populations implicated in organic matter turnover suggest that microbes in Oregon coastal ecosystems use allochthonous resources that are transported into the coastal ocean during winter, and that these resources help shape the coastal food web during the winter season.

中文翻译：

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冬季河流羽流塑造了俄勒冈海岸异养微生物的群落组成和活动

沿着俄勒冈州中部边缘的河流和河口在冬季将大量源自河流的陆源材料输送到沿海海洋中，这些材料可能会因局部密度梯度和风力强迫而被困在近岸沿海洋流中。这些大量和持久的外来输入对俄勒冈沿海地区冬季生物活动的影响尚不清楚。我们比较了俄勒冈州中部海岸 2 条漂浮的沿海河流羽流内部和外部的原核生物群落，以了解羽流条件与原核生物种群分布之间的关系，这些原核生物种群通过转化碳和氮化合物而形成冬季沿海食物网的基础。近岸羽流区内的自由生活和粒子相关群落与羽流影响之外的群落显着不同。颗粒有机物浓度与几个拟杆菌种群的分布相关，这些种群在沿海生态系统的复杂有机物降解中发挥着既定的作用。羽状条件还与已知可降解陆源材料的海洋 Gammaproteobacteria 相关。采样站的异养呼吸率峰值发生在当地羽流颗粒最大值处，这表明通过河流羽流输送到沿海海水的颗粒资源可能被共定位的异养微生物使用或转化。综合起来，