Event Deposition and Biological Response of a Saline Inland Pond: Storrs Lake, San Salvador Island, Bahamas

Because of its position within the southwestern Atlantic, San Salvador Island has been the site of many hurricane strikes throughout its history. As such, it remains an effective setting in which to examine hurricane intensity in the Late Holocene. The lakes along the island's margin provide a depositional archive recording the paleotempestites from these storm events. Storrs Lake is a shallow (<2m), hypersaline (>66µs) lake located along the eastern side of the island and is separated from the ocean by Holocene dunes. It, like other lakes on SSI, is constantly recording climatic changes, vegetation shifts and the history of colonization. This study addresses the following questions: 1) What is the depositional history of Storrs Lake through the last 4,000 years and 2) Can we see large storm events in the sediment record and determine the biologic response to these events?

We recovered cores from Storrs Lake that varied in length from 5 to 200 cm, including transects across the Fortune Hill Basin. These cores were analyzed for organic and carbonate content, dry bulk density, grain size, chemical composition, sediment fabric, trace elements, X-ray fluorescence, and ostracode and mollusk faunal composition. Preliminary results indicate that large storms can be identified through time by a distinct change in grain size and a change in dry bulk density. The adjacent dunes have been mapped and sediment analyzed. The allochthonous sand found within the basin matches the sand found on the dune faces and identified as storm wash-over deposits. Biologic patterns suggest that species richness and abundance change after these large storm events, possibly due to the freshening that occurred from the storm and a change in the basin substrate. Algal mats, or stromatolites that are prevalent throughout many of the lakes on SSI, also have a documented response to these freshening events.