珠江口藻毒素检出水域小型真核浮游生物及其共附生细菌群落特征分析OA北大核心CSCDCSTPCD

Harmful algae significantly threaten marine ecosystem stability and public health.However,their impact on planktonic community diversity and interspecific interactions remains unclear.In June 2019,microplanktons(>20 μm in size)were sampled from the Pearl River Estuary,where harmful algae as well as the phycotoxins pectenotoxin-2(PTX2)and homo-yessotoxin(hYTX)were detected.DNA metabarcoding was employed to analyze the diversity,assembly mechanisms,and co-occurrence networks of microeukaryotic plankton and associated bacterial communities.Results showed that both communities were mainly shaped by the abundance of toxic/harmful algae.These were di-vided into two clusters:high and low abundance(H and L groups,respectively).However,the α-diversity did not show any significant intergroup differences.The plankton community was dominated by Bacillariophyta(18.73%)and Dinophyceae(16.58%),while the bacterial community was dominated by γ-(73.79%)and α-(13.76%)Proteobacteria.Temperature and cross-domain biotic interactions co-shaped the plankton community.It was additionally influenced by salinity and hYTX concentration.However,the bacterial communities responded to chlorophyll a and dissolved O2,while exhibiting an enhanced sensitivity to environmental filtering.Stochastic processes(dispersal limitation and eco-logical drift)governed community assembly.Co-occurrence networks were dominated by the associations among Ba-cillariophyta,Dinophyceae,Syndiniales,and Proteobacteria,accounting for 29.5%of the total edges.Non-abundant taxa constituted 77.32%of the nodes and 76.78%of the keystone OTUs,while 34.8%of the edges linked to these OTUs were represented by eukaryote-bacteria associations.In summary,this study elucidates the impacts of toxic algae on the community structure of microeukaryotic plankton and associated bacteria,providing a foundation for further research into the ecological roles of non-dominant taxa.