FORAMINIFERAL ASSEMBLAGES AS BIONDICATORS IN AN ISOLATED REEF SETTING OF THE CARIBBEAN REALM (ALBUQUERQUE CAY, COLOMBIAN CARIBBEAN)

The San Andrés Archipelago (NW Colombia) constitutes a biological hotspot for the Western Caribbean. However, overpopulation and unrestrained exploitation of their natural resources jeopardizes the continuity of key ecosystems in most of the islands. Due its more isolated location in the archipelago, the Albuquerque Cay has been monitored in recent years and several marine organisms have been studied as possible bioindicators.

A survey of the living foraminifers of the cay illustrate that assemblages resemble the conditions of a typical reef lagoon for the Caribbean realm. The studied material, belonging to reef lagoon and shore face conditions comprise porcelanaceous forms (Quinqueloculina, Triloculina), and symbiont bearing genera such as Archaias, Amphistegina, Heterostegina, Sorites, among others. Selected calcareous taxa such as Rotorbinella and Cymbaloporetta are also present in variable proportions. In general, there is not a clear segregation of the foraminiferal assemblages which suggests homogenous environmental conditions for the cay. Therefore, a preliminary test of the FORAM Index (FI) was conducted in the reef lagoon samples in order to make ecological assessments. FI values suggests moderate to good conditions for the environments of Albuquerque Cay, contrasting with less promissory values of the FI in other parts of the archipelago.

Therefore, this preliminary survey reinforces the great potential that foraminiferal assemblages might have as bioindicators for this part of the Caribbean Sea.