Chemical Oxygen Demand: A Key Determinant in Shaping Biological Community Structure

In response to growing global concerns about the impacts of environmental changes on marine ecosystems, scientists have increasingly turned their attention to the role of aquatic environments in shaping biodiversity. This study aimed to assess the biodiversity of northern Liaodong Bay in the context of environmental changes and to elucidate the mechanisms by which aquatic environmental factors influenced different biological groups. Based on the 2024 survey data of phytoplankton, zooplankton, macrobenthos and nekton, the average Marine Biodiversity Index (MBI, a comprehensive index) was calculated as 53.08, corresponding to a moderate evaluation level. This suggests a relatively rich diversity of marine species and a fairly even distribution. A correlation analysis between water quality factors and biological community structure reveals that biodiversity in the bay is under pressure from multiple environmental stressors, including elevated COD and heavy metal contamination (e.g., Pb). The study recommends targeted biodiversity conservation strategies and ecosystem management measures to enhance the resilience of the bay’s ecosystem and mitigate the effects of these environmental stressors.