It is well accepted that temperature is a key driver of general marine biodiversity, but its specific role in the community assembly and interaction of microeukaryotic plankton remains elusive. Here, we used metabarcoding approach to investigate the diversity, assembly mechanism and molecular ecological network (MEN) of microeukayrotic plankton (0.45-200 um) in the South Yellow Sea (SYS) across four seasons in 2019, and compared their dependencies on temperature between SYS and global oceans. Over 125 samples from the SYS were clustered into four groups mainly associated with temperature and dissolved oxygen: i) spring, ii) the surface water in summer and autumn, iii) the Yellow Sea cold water mass (YSCWM) and some bottom waters in winter, iv) others in winter. Alpha diversity showed a U-shaped correlation with temperature, but decrease linearly with dissolved oxygen. Moreover, temperature was also the main factor mediating the contribution of stochastic and deterministic assembly processes in microeukaryotic plankton community as the proportion of determinism increased with temperature. The MENs of the communities with higher determinism (group i and ii) exhibited lower negative cohesion and higher vulnerability, while that with higher stochasticity (group iii and iv) showed the opposite. Further analysis using public metabarcoding data of microeukaryotic plankton (3-5 um) from global oceans (the Tara Oceans expeditions) showed the similar pattern of community assembly mechanisms and MENs driven by temperature, suggesting that warming reduced the interspecies competition and the network stability. Our results from a year-round regional data and global data can help us to understand the long-term response of marine microeukaryotic plankton to climate change, which is distinct from that of prokaryotes and microbes from other ecosystems.

Temperature,Community assembly mechanism,Molecular ecological network,Microeukaryotic plankton,the Southern Yellow Sea