Recent benthic foraminiferal assemblages and sedimentary facies from two atolls of Maldivian Archipelago (Indian Ocean): Reef and seagrass indicators

Abstract

[eng] The Maldives Archipelago is an isolated tropical carbonate platform in the Indian Ocean that includes diverse reef and perireef modern environments. We provide a study of benthic foraminiferal assemblages from seagrass and macroalgae dominated habitat and from unvegetated environments. A total of 252 species of benthic foraminifera were identified from 35 samples and biotic indexes were calculated. The assemblages are dominated by genus Amphistegina, and its spatial distribution appears related to depth and seagrass cover, but it is also influenced by hydrodynamic energy. Multivariate analysis distinguished six principal assemblages, being A. lobifera-A. radiata assemblage associated with unvegetated seabed from 15 to 76 meters water depth (mwd). The study of recent tropical vegetated and unvegetated benthic associations is also useful for paleoecological and paleoenvironmental interpretations. The foraminiferal indexes (FI and I LS) are calculated to assess the health of reefal communities and compared with those given by previous works in the investigated areas.