Data from: The effect of top-predator presence and phenotype on aquatic microbial communities

The presence of predators can impact a variety of organisms within the ecosystem, including microorganisms. Because the effects of fish predators and their phenotypic differences on microbial communities have not received much attention, we tested how the presence/absence, genotype, and plasticity of the predatory three-spine stickleback (Gasterosteus aculeatus) influence aquatic microbes in outdoor mesocosms. We reared lake and stream stickleback genotypes on contrasting food resources to adulthood, and then added them to aquatic mesocosm ecosystems to assess their impact on the planktonic bacterial community. We also investigated whether the effects of fish persisted following the removal of adults, and the subsequent addition of a homogenous juvenile fish population. The presence of adult stickleback increased the number of bacterial OTUs and altered the size structure of the microbial community, whereas their phenotype affected bacterial community composition. Some of these effects were detectable after adult fish were removed from the mesocosms, and after juvenile fish were placed in the tanks, most of these effects disappeared. Our results suggest that fish can have strong short-term effects on microbial communities that are partially mediated by phenotypic variation of fish.

捕食者的存在可对生态系统内的各类生物产生影响，其中亦包含微生物。鉴于鱼类捕食者及其表型差异对微生物群落的影响尚未得到充分研究，我们通过室外中型实验生态系统（mesocosms），探究了捕食性三刺鱼（Gasterosteus aculeatus）的存在与否、基因型以及表型可塑性对水生微生物的影响。我们将湖泊型与溪流型三刺鱼基因型在差异化食物资源下饲养至成体，随后将其接入水生中型实验生态系统，以评估其对浮游细菌群落的影响。我们同时探究了：在移除成体三刺鱼并后续接入均质化幼鱼种群后，鱼类对群落的影响是否仍会持续。成体三刺鱼的存在可提升细菌操作分类单元（Operational Taxonomic Unit，OTU）的数量，并改变微生物群落的大小结构；而其表型则会影响细菌群落的组成。在将成体三刺鱼移出中型实验生态系统后，部分影响仍可被检测到；而当幼鱼被接入实验水槽后，这类影响大多消失。本研究结果表明，鱼类可对微生物群落产生显著的短期影响，这类影响部分由鱼类的表型变异所介导。