Study of microfauna foraminifera as bioindicator for coral reef condition in Tambelan Island, Riau Island Province

Abstract

Tambelan Islands is one of the coral reef habitats in Indonesia. This area is the southern part of Natuna Sea and South China Sea Throughflow (SCSTF) exit area, which influenced the dynamics of the ocean and climate in Indonesia. Foraminifera is one of the potential bioindicator that can be used to determine the conditions of waters and the environmental health of coral reef. Twenty surface sediment samples were taken and quantitative analysis were made in order to obtain the condition of waters. This analysis including calculation of abundance, community structure, and analysis of biozonation (cluster and SHEBI). Meanwhile, to determine the condition of coral reef was using FORAM Index (FI). The results showed that there were 52 species of benthic foraminifera included in 41 genera. The most abundant genera were Amphistegina (average 28.08%) and Operculina (average 23.85%) which were a type of genera that associated with coral reefs. The FI values range from 3.57–9.12 indicating that environmental conditions are conducive to coral reefs. Biozonation from the cluster and SHEBI showed different results, indicating that the abundance of foraminifera in research area are influenced by complex factors such as substrate conditions and the activities on land.