A late Holocene paleoenvironmental reconstruction of a coastal lake in northeastern Dominican Republic

Abstract

Coastal lakes, lagoons, and wetlands often provide excellent records of environmental change related to both marine and terrestrial processes. Although coastal paleoenvironments in the Caribbean have been a subject of increasing interest, long-term environmental reconstructions from lakes on the Atlantic side of the Caribbean islands are lacking. Laguna Limon is a freshwater lake in the El Seibo province of northeastern Dominican Republic. We collected a 315-cm sediment core from the center of the lake to examine lake evolution using loss-on-ignition and foraminiferal analysis. Loss-on-ignition results indicated the presence of a low-energy lagoon in the lake's present location between about 4700 and 1400 cal yr BP. During this period a foraminiferal assemblage dominated by the brackish-water Ammonia parkinsoniana but also containing relatively-abundant normal-marine salinity taxa (e.g., Quinqueloculina spp., Archaias angulatus, and Trochulina rosea) gradually was replaced by a low-diversity assemblage dominated by Ammonia tepida and Ammonia parkinsoniana, indicating a gradual decline in salinity due to the lagoon's growing isolation from the Atlantic Ocean. By 1400 cal. Yr. BP, the lake had become a shallow wetland, indicated by sediments with a high organic content. At 1200 cal. Yr. BP the lake flooded with freshwater, as it remains today. This study provides context for ongoing research into the environmental and human history of the Laguna Limon area.