419 / 2024-09-16 18:18:05
Deciphering the key multiple factors shaping the relative success of core mixotrophs across spatiotemporal scales
core mixotrophs,multiple factors,trophic modes,Generalized Additive Mixed Model,tipping point
Session 19 - Marine Plankton Ecosystem and Global Climate Change
Abstract Accepted
Deciphering the spatiotemporal dynamics and relative competitive advantages of trophic functional traits under multiple factors has been a long-standing challenge. Here, our study conducted high-density spatial and time-series sampling in the subtropical coastal waters. By integrating the core taxa identification with robust simulation modeling, we reveal key environmental factors influencing the diversity patterns and relative success of the three core trophic groups (autotroph, heterotroph, and mixotroph), with a particular focus on core mixotrophs. Temporally, core mixotrophs exhibited a higher relative proportion during the spring and winter, while heterotrophs were more competitive in the summer and autumn . Despite significant seasonal differences, core mixotrophs demonstrated a more uniform spatial distribution pattern. And the differences in community structure were more shaped by Physiochemistry and Nutrient categories rather than geographical distance. While seasonal preferences were observed in the environmental responses of the trophic groups, temperature, dissolved oxygen (DO), and nitrate-nitrogen (NO3-N) were identified as the most critical factors affecting the whole core mixotrophs by random forest algorithm. Furthermore, through univariate two-dimensional regression and three-dimensional Generalized Additive Mixed Model (GAMM), we captured the abundance changes of core mixotrophs across the gradients of three factors and characterized the coupled additive or antagonistic compound effects. Remarkably, the tipping point revealed that moderate level of NO3-N, lower temperature and DO are the potential optimal ecological threshold for core mixotrophs, which contrasts with the results from single-factor regressions. GAMM indicated that the preferred niche shifted upward for NO3-N and downward for DO when considering multiple factors, while temperature remained constant. Our findings highlight the strong impact of temperature and the importance of considering multiple factors. Taken together, this study links the ecological niche preference of core trophic functional traits with key multiple factors, facilitating a more precise monitoring and comprehension of the spatiotemporal dynamics of the plankton food web and its responses to changing environment at regional scales under scenarios of escalating global climate change and anthropogenic disturbances.