Temporal and spatial distribution of modern ostracod species of Lago Enriquillo (SW Dominican Republic)

Understanding modern species´ ecological preferences and distribution are prerequisites for their application as proxies in paleoenvironmental reconstructions. This knowledge is, however, missing for the majority of tropical species. In order to contribute to close this gap we characterize the ostracod fauna of Lago Enriquillo in the Dominican Republic. Located in the Main Development Region of North Atlantic tropical storms it has experienced rapid water level fluctuations in the past that are assumed to be related to storm activities. This highlights the relevance of the lake for reconstructions of changes in precipitation and storm activity. Living ostracods inhabiting Lago Enriquillo were analyzed in March and September (dry and rainy season) 2022 with the aim to understand their temporal and spatial distribution and changes in morphological characteristics (valve size). Lago Enriquillo is a warm (27.8-33.8°C), mesohaline (43.7-46.3 psu) and generally slightly alkaline lake (pH: 7.5-8.1) with a max. water depth of 25 m. The spatially variable ostracod fauna is composed of Cyprideis similis, Perissocytheridea cribrosa and Thalassocypria sarbui. The three species reflect the lake’s seasonality differently in terms of their morphology and population structure. C. similis occurred continuously but is smaller in spring than in autumn. P. cribrosa inhabits the lake only in autumn and shows a distinct distribution dominating littoral areas with seasonal freshwater inflow. T. sarbui forms larger populations only in spring and forms only tentative size clusters. Their occurrence is restricted to water depths above (temporary) minima of oxygen (below 10 – 14 m).