Abstract While nutrient loading has affected all levels of Lake Winnipeg’s ecology, its greatest influence has likely been on the microbial community. In addition to eutrophication, zebra mussels (Dreissena polymorpha) have recently invaded the ecosystem and threaten food web dynamics. Their filter-feeding predation and association with bacteria, specifically phototrophs, was investigated. A sampling trip to Lake Winnipeg in October 2017, focused on the isolation, enumeration, and identification of aerobic anoxygenic phototrophs in littoral water, sediment, and tissues of mussels. Gimli, Patricia, and Grand beaches, separated by >15 km across the South Basin, had similar bacterial counts when cultivated on rich organic, BG-11, purple non-sulphur, and K2TeO3-supplemented media. Culture-based enumeration on rich organic medium revealed 1.74% of heterotrophs from littoral waters were aerobic anoxygenic phototrophs, and represented 13.98% within sediments. In contrast, 0.48, 1.15, and 0.16% of cultured heterotrophs were aerobic anoxygenic phototrophs within zebra mussel gill, gut, and gonadal tissues, respectively. High-throughput sequencing of bacterial 16S V4 rDNA maintained similar trends in respective bivalve organs, where 0.22, 1.13, and 0.20% of total 16S genes belonged to these phototrophs. Several Sphingomonadaceae isolates were recovered from gut tissues, all with filamentous morphology large enough for predation. Bioaccumulation of metals was also studied in D. polymorpha. All tested associated aerobic anoxygenic phototrophs were capable of resisting the metalloid oxide tellurite. The consistent distribution of aerobic anoxygenic phototrophs within microbial communities across Lake Winnipeg, and their predominance in the gut tissues of zebra mussels suggested bacterial consumption by this invasive species.

中文翻译：

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温尼伯湖沿岸地区有氧缺氧光养生物和斑马贻贝的关联，多形德雷塞纳

摘要 虽然养分负荷影响了温尼伯湖生态的各个层面，但其最大的影响可能是对微生物群落的影响。除了富营养化，斑马贻贝 (Dreissena polymorpha) 最近侵入生态系统并威胁食物网动态。研究了它们的滤食捕​​食和与细菌，特别是光养生物的关联。2017 年 10 月对温尼伯湖进行了一次采样之旅，重点是隔离、计数和鉴定沿海水域、沉积物和贻贝组织中的好氧缺氧光养生物。Gimli、Patricia 和 Grand 海滩在南盆地相隔 15 公里以上，在富含有机、BG-11、紫色非硫和 K2TeO3 补充培养基上培养时，细菌数量相似。在丰富的有机培养基上进行的基于培养的计数显示 1。来自沿海水域的 74% 的异养生物是好氧缺氧光养生物，在沉积物中占 13.98%。相比之下，斑马贻贝鳃、肠道和性腺组织中分别有 0.48、1.15 和 0.16% 的培养异养生物是有氧无氧光养生物。细菌 16S V4 rDNA 的高通量测序在各自的双壳类器官中保持相似的趋势，其中 0.22、1.13 和 0.20% 的总 16S 基因属于这些光养生物。从肠道组织中回收了几种鞘氨醇单胞菌科分离株，它们都具有足够大的丝状形态以供捕食。还在 D. polymorpha 中研究了金属的生物积累。所有测试的相关有氧无氧光养生物都能够抵抗准金属氧化物亚碲酸盐。