Boden Lisa, Bludau Dana, Sieber Guido, Deep Aman, Baikova Daria, David Gwendoline M, Hadžiomerović Una, Stach Tom L, Boenigk Jens
Department Biodiversity, University of Duisburg-Essen, Essen, NRW 45141, Germany.
Center for Water and Environmental Research, University of Duisburg-Essen, Essen, NRW 45141, Germany.
ISME Commun. 2025 Mar 21;5(1):ycaf049. doi: 10.1093/ismeco/ycaf049. eCollection 2025 Jan.
Microbial predator-prey interactions play a crucial role in aquatic food webs. Bacterivorous protists not only regulate the quantity and biomass of bacterial populations but also profoundly influence the structure of bacterial communities. Consequently, alterations in both the quantity and quality of protist bacterivory can influence the overall structure of aquatic food webs. While it is well-documented that changes in environmental conditions or the occurrence of abiotic stressors can lead to shifts in microbial community compositions, the impact of such disturbances on food selection remains unknown. Here, we investigated the effects of elevated temperature and salinization on food selectivity of heterotrophic nanoflagellates by monitoring the uptake of preselected target bacteria via catalyzed reporter deposition fluorescence hybridization and fluorescence microscopy. Our results indicate that salinization, but not increased temperature, significantly increased the flagellates' selection against (Actinomycetota). However, the effect of the reduced grazing pressure was counterbalanced by the negative effect of increased salinity on the growth of Actinomycetota. Our results suggest that the effect of stressors on the feeding behavior of protistan predators may strongly affect the composition of their prey community, when bacterial taxa are concerned that are less sensitive to the particular stressor.
微生物捕食者 - 猎物相互作用在水生食物网中起着至关重要的作用。食细菌原生生物不仅调节细菌种群的数量和生物量，还深刻影响细菌群落的结构。因此，原生生物食细菌作用在数量和质量上的改变都会影响水生食物网的整体结构。虽然有充分的文献记载环境条件的变化或非生物应激源的出现会导致微生物群落组成的转变，但这种干扰对食物选择的影响仍然未知。在这里，我们通过催化报告沉积荧光杂交和荧光显微镜监测预选目标细菌的摄取，研究了温度升高和盐渍化对异养纳米鞭毛虫食物选择性的影响。我们的结果表明，盐渍化而非温度升高显著增加了鞭毛虫对放线菌门的排斥选择。然而，放牧压力降低的影响被盐度增加对放线菌门生长的负面影响所抵消。我们的结果表明，当涉及对特定应激源不太敏感的细菌类群时，应激源对原生生物捕食者摄食行为的影响可能会强烈影响其猎物群落的组成。
