Two major issues for marine coastal ecosystems and their biodiversity are increasing sea surface temperature and nutrient concentrations (eutrophication). Especially the combined effect of increasing temperature and eutrophication can have negative impact to benthic organisms such as corals and molluscs, but could enhance the expansion of macroalgae, sponges, and cyanobacteria. Therefore, the reefs of the future will likely look and function differently from current coral dominated ecosystems. A major challenge to science is to understand and predict the response of marine species composition and community from environmental perturbation. In an attempt to fill this knowledge gap, marine lakes (islands of seawater within land) of Raja Ampat, Indonesia will be used as model systems to study future climate change scenarios and to predict the responses of coastal species communities under different degrees of eutrophication. Mollusc species diversity as well as their functional traits in marine lakes and coastal areas of Papua will be recorded and identified to assess differences in community composition and functional diversity of mollusc among sites under different scenarios. Furthermore, temporal and spatial variation in the total benthic community composition among marine lakes and reefs in response to environmental change will be assessed and the related shift in the energy flow from primary producers to consumers. Thus, food web structure will be elucidate across natural communities in the marine lake model systems. Overall, the proposed PhD project will contribute to scientific knowledge on marine biodiversity and species community responses to projected future environmental conditions.