Coral reef condition at different trophic status in marginal waters of Bone Bay, South Sulawesi, Indonesia

Coral reef ecosystems are best suited to live in clear water conditions and oligotrophic trophic status, but marginal waters with high trophic levels in Bone Bay also have coral reef ecosystems living in them. This study was conducted in August 2023 with the aim of determining the percentage of live coral cover and its condition at different trophic status in marginal waters. Based on the processing of water quality data at 16 observation stations using the TRIX Index, four categories of water trophic status were identified, namely very high (hypertrophic), high (eutrophic), medium (mesotrophic), and low (oligotrophic) categories. Water conditions in areas close to the coastline have a higher trophic status compared to distant areas. The percentage of hard coral cover in eutrophic waters is 59.08%, in mesotrophic waters 63.63% and oligotrophic waters 43.15%. Based on PCA analysis, environmental conditions that correlate with hard corals are temperature, chlorophyll-a, TSS, pH, phosphate, nitrate and turbidity. It is anticipated that the results of this study can be a consideration for coastal area managers to protect coral reefs in marginal waters as the world's future reef area.