Department of Ecology Environment and Plant Sciences, Stockholm University, Stockholm, Sweden.
Institute for the Oceans and Fisheries, University of British Columbia, Vancouver, Canada.
Microb Ecol. 2024 Feb 26;87(1):48. doi: 10.1007/s00248-024-02362-7.
In aquatic ecosystems, zooplankton-associated bacteria potentially have a great impact on the structure of ecosystems and trophic networks by providing various metabolic pathways and altering the ecological niche of host species. To understand the composition and drivers of zooplankton gut microbiota, we investigated the associated microbial communities of four zooplankton genera from different seasons in the Baltic Sea using the 16S rRNA gene. Among the 143 ASVs (amplified sequence variants) observed belonging to heterotrophic bacteria, 28 ASVs were shared across all zooplankton hosts over the season, and these shared core ASVs represented more than 25% and up to 60% of relative abundance in zooplankton hosts but were present at low relative abundance in the filtered water. Zooplankton host identity had stronger effects on bacterial composition than seasonal variation, with the composition of gut bacterial communities showing host-specific clustering patterns. Although bacterial compositions and dominating core bacteria were different between zooplankton hosts, higher gut bacteria diversity and more bacteria contributing to the temporal variation were found in Temora and Pseudocalanus, compared to Acartia and Synchaeta. Diet diatom and filamentous cyanobacteria negatively correlated with gut bacteria diversity, but the difference in diet composition did not explain the dissimilarity of gut bacteria composition, suggesting a general effect of diet on the inner conditions in the zooplankton gut. Synchaeta maintained high stability of gut bacterial communities with unexpectedly low bacteria-bacteria interactions as compared to the copepods, indicating host-specific regulation traits. Our results suggest that the patterns of gut bacteria dynamics are host-specific and the variability of gut bacteria is not only related to host taxonomy but also related to host behavior and life history traits.
在水生生态系统中，浮游动物相关细菌通过提供各种代谢途径和改变宿主物种的生态位，对生态系统和营养网络的结构具有巨大影响。为了了解浮游动物肠道微生物群的组成和驱动因素，我们使用 16S rRNA 基因研究了波罗的海四个浮游动物属在不同季节的相关微生物群落。在所观察到的属于异养细菌的 143 个扩增序列变异体 (ASV) 中，有 28 个 ASV 在整个季节的所有浮游动物宿主中共享，这些共享的核心 ASV 代表了浮游动物宿主中相对丰度的 25%以上，高达 60%，但在过滤水中的相对丰度较低。浮游动物宿主身份对细菌组成的影响大于季节性变化，肠道细菌群落的组成表现出宿主特异性聚类模式。尽管浮游动物宿主之间的细菌组成和占主导地位的核心细菌不同，但与 Acartia 和 Synchaeta 相比，Temora 和 Pseudocalanus 中的肠道细菌多样性更高，且更多的细菌有助于时间变化。硅藻和丝状蓝藻的饮食与肠道细菌多样性呈负相关，但饮食组成的差异并不能解释肠道细菌组成的差异，这表明饮食对浮游动物肠道内部条件有一般影响。与桡足类相比，Synchaeta 保持了肠道细菌群落的高度稳定性，细菌间相互作用出人意料地低，这表明宿主具有特异性的调节特征。我们的研究结果表明，肠道细菌动态的模式是宿主特异性的，肠道细菌的可变性不仅与宿主分类有关，还与宿主行为和生活史特征有关。
