1431 / 2024-09-27 08:02:41

Nutrient enrichment destabilizes multidimensional macrofaunal diversity in tropical coastal waters

coastal waters,community structure,eutrophication,macrofaunal diversity

Rapid agricultural development has led to eutrophication in coastal waters, negatively impacting the protection of biodiversity and the functioning of marine ecosystems. Harsh natural and contaminated conditions constrain marine biotic factors, and the community structure of their environments can be altered. However, the mechanism responsible for such effects remains unclear, with few studies having addressed how eutrophication influences the natural gradient shift in the community structure. Herein, a field survey was conducted in tropical coastal waters adjacent to farmland to examine how biodiversity responds to environmental changes. We found greater habitat quality and macrofaunal diversity in eastern and western regions than in the center region. When the marine habitat was under slight disturbance, its macrofaunal diversity was higher, having a rich array of sensitive and pollution-tolerant species. With deteriorating habitat quality, the structure of the macrofaunal community tended to become simpler. Different environmental factors were decisive for benthic species whose sensitivity to them varied. Natural variables, such as pH and water transparency, significantly affected the sensitive species. By contrast, eutrophication factors, such as suspended solids, affected the proportion of pollution-tolerant species present. Overall, the habitat quality in the study area was above the medium level, and the contribution of natural environmental variables amounted to a 63% weight. Hence, they constituted the main factor affecting the macrofaunal community. Hierarchical succession theory and the intermediate disturbance hypothesis could explain well the dynamic changes of community. This study is helpful not only for inferring community composition, structure, and function but also for determining the impact of contaminants on macrofauna, and for providing insight into their community responses following marine disturbances.