Sedimen Terendap dan Terperangkap pada Turf Algae di Terumbu Karang Kepulauan Spermonde = Sediment Deposited and Trapped on Turf Algae in Coral Reefs of the Spermonde Archipelago

Background. The Spermonde Archipelago is an example of coral reefs in turbid waters that are heavily influenced by human activities and coastal development, resulting in a spatial gradient of water turbidity from Makassar to the outer islands of Spermonde. This condition affects the dynamics of the coral reef ecosystem, including turf algae. Turf algae are capable of trapping and stabilizing sediments in the waters. Objective. This study aims to analyze the relationship between turf algae height and sediment thickness on turf algae growing on different substrates (hard substrate/rock and coral rubble), as well as to analyze the sediment load and composition trapped in turf algae in the Spermonde Archipelago. Methods. The study was conducted in coral reef areas at a depth of 3-5 meters on eight islands in the Spermonde Archipelago, based on their distance from the mainland (Makassar). The measurement of turf algae height and sediment thickness on turf algae was carried out on two different substrates (hard substrate/rock and coral rubble). Sediment load and composition were analyzed using the Loss on Ignition method and sediment grain size analysis. Statistical analysis was performed using Two-way ANOVA and linear regression. Results. The average height of turf algae on coral rubble substrate (0.58 ± 0.01 cm) was greater than on hard substrate (0.44 ± 0.01 cm), while sediment thickness on coral rubble substrate (0.11 ± 0.006 cm) was smaller than on hard substrate (0.14 ± 0.007 cm). Sediment load on turf algae decreased based on the distance from the mainland (Makassar), with Lae-Lae Island having the highest sediment load (414.29 gr/m2) and Kapoposang Island the smallest (5.98 gr/m2). The sediment within turf algae at the research sites falls into the sand category, except for Lae-lae Island, which falls into the muddy sand category. Conclusion. Turf algae are positively correlated with deposited and trapped sediments on them. The sediment accumulation on turf algae shows a decreasing pattern based on the distance from the mainland (Makassar).