Spatiotemporal Differences in Marine Environment Quality in China and the Influencing Factors

Based on 2011-2020 panel data for China's coastal cities and provinces, this study used the entropy method and Theil index to measure marine environment quality (MEQ) and construct MEQ indicators. We used the Theil index to measure heterogeneity in regional MEQ and a geographic detector model to explore the driving factors of MEQ. Our study resulted in the following findings: (1) MEQ increased in waves, but the overall quality was relatively low, forming a spatial distribution pattern of high in the north and south, and low in the east. Moreover, MEQ was polarized between provinces. (2) Regional MEQ showed a distribution pattern of significant differences between the east and the north but small differences in the south. The regional gap was significant but gradually narrowing, with the contribution rate of intra-regional differences reaching over 90%. Meanwhile, interregionalinter-regional differences were relatively small and showed a balanced development trend. (3) Agricultural and aquaculture pollution were found to be the main factors affecting MEQ. The effect of marine engineering pollution was significantly increasing while that of environmental regulation intensity was relatively weak. The interaction between different driving factors mainly manifested as dual-factor enhancement and nonlinear enhancement.