A Baseline for Recognizing Change: Diversity and Biogeography of the Maldives Atolls' Shallow Water Foraminifera

The Maldives archipelago has become one of the most famous touristic locations in the world and is under noticeable pressure from various human activities such as extensive fisheries and tourism.  Because of this, the Pristine Seas Project (National Geographic) included the area in its efforts to fill existing knowledge gaps such as its species diversity and distribution as part of a larger aim to establish science-based protected marine reserve zones. Foraminifera, unicellular marine marvels, are renowned for their use as an environmental bioindicator of broader conditions. The present study investigates the diversity and biogeographic patterns of recent shallow water foraminifera that inhabit three distinctive atolls in the Maldives archipelago. Sediment samples were collected from reef and lagoon environments of the 26 distinct localities across three southern Maldives atolls - Addu, Fuvahmulah, and Huvadhoo. The most abundant taxa are Amphistegina followed by Calcarina, Heterostegina and Sorites. A species richness and diversity varied among sampling sites, with higher richness observed in MV18 station (Addu Atoll). Cluster analysis revealed distinct foraminiferal assemblages associated with different reef zones and sediment types. Here we discuss environmental parameters such as depth, substrate characteristics, ocean current influence, foraminiferal distribution patterns within and between different atolls of Maldives and also in comparison to the greater Indian Ocean datasets. The empirical data generated in this study offers a better understanding of ecosystem biodiversity in this remote location which may act as a baseline for future experimental and ecological studies, assessing possible anthropogenic influences and provides valuable insights into the regional vulnerability to climate change. Present study highlights the importance of habitat, microhabitat conservation and contributes to our knowledge of Indian Ocean marine biodiversity and biogeography.

Keywords: Indian Ocean, assemblage, habitat, distribution, large benthic foraminifera