Offshore wind farms and associated wave-induced processes influence macrobenthic diversity and biomass in coastal ecosystems

Abstract

Appropriate decision making for ecosystem conservation is contingent on understanding the ecosystem. To evaluate the effect of offshore wind farms (OWFs) and predict future changes in benthic ecosystems, data on influencing factors must be collected. We aimed to assess the effect of OWF in a study area located off the central west coast of Korea. Based on the diversity and biomass anomaly criteria established for the west coast of Korea, we classified 28 survey rounds from 2014 to 2022 as anomalous or normal based on the number of anomalous samples. Regression analyses were performed to determine the sources of diversity/biomass variation. In any given period, the biomass anomalous samples/rounds were more dominant than those related to diversity. Significant factors identified during regression analyses included sediment, depth, suspended particulate matter, and weather-related variables, such as monthly averages of wind speed and significant wave heights, mainly measured at land-based weather stations. Biomass exhibited stronger correlations with weather variables than diversity. Binary logistic regression predicted anomaly occurrence at wind speeds ≥2.84 or ≥1.60 m/s for diversity and at ≥2.70 or ≥1.86 m/s for biomass, depending on the mild or harsh conditions of significant wave heights or maximum wind speed. Thus, our study showed that wave-induced processes and other natural factors influence macrobenthic diversity and biomass, and these predictions were potentially improved by measurements from land-based weather stations. The expected reduction in wave energy owing to wake effects from the OWF is expected to increase the productivity of benthic ecosystems.