Abstract:

Community stability, the capacity to maintain ecological structure and function despite environmental changes, is pivotal for ecosystem resilience and biodiversity conservation. While understanding the dynamics of microbial communities is essential for predicting ecosystem responses to disturbances, limitations in traditional methods often hinder comprehensive insights. Environmental DNA (eDNA) metabarcoding, combined with advanced network analysis, provides a robust framework for unraveling ecological interactions and stability dynamics across diverse temporal and spatial scales.

In this dissertation, I applied eDNA-based approaches to assess microbial community stability in subtropical coastal waters. In Chapter 1, using eDNA metabarcoding and Weighted Gene Co-expression Network Analysis (WGCNA), I reconstructed cross-domain interaction networks to identify keystone taxa, revealing region-specific differences in network complexity and stability. Chapter 2 expanded this investigation by evaluating seasonal stability of free-living and particle-attached bacterial communities through long-term sampling and microbial co-occurrence networks, demonstrating the distinct influences of abiotic and biotic factors. Keystone taxa such as Nitrosopumilus and Synechococcales were found to play critical roles in community resilience under varying environmental conditions. Chapter 3 utilized Unified Information-theoretic Causality (UIC), a non-linear analytical framework, to explore temporal dynamics and predict the impacts of environmental fluctuations on microbial stability. 

These findings underscore the versatility of eDNA in understanding ecological networks, the critical role of keystone taxa in maintaining stability, and the utility of long-term datasets for forecasting ecosystem responses. This work contributes to advancing marine biodiversity conservation and developing strategies for sustainable ecosystem management in the face of rapid environmental change. 

All Are Welcome!