T105 Surf’s Up: New Insights on the Geology, Karst, and Paleontology of Carbonate Systems of the Bahama Archipelago (Posters)

Monday, 5 November 2012
9:00 AM - 6:00 PM
Hall B

COMPARISON BETWEEN BIOTA OF TWO LAKES ON SAN SALVADOR ISLAND, BAHAMAS

Paper number: T105-6
Program: Technical Sessions
Time: 9:00 AM – 6:00 PM

Authors

Abstract

Localized floral and faunal communities respond to anthropogenic changes in ways that can be measured both qualitatively and quantitatively. Even close-by lakes can have different anthropogenic histories. For example, San Salvador Island is in the southeast Bahamian archipelago and has an array of inland lakes, each of which has experienced some degree of human impact. We studied two blue holes on San Salvador: Watling's Blue Hole, which has a history of being used by people—having a constructed wall around its perimeter as well as four pens on the northeast side of the lake, and Blue Hole Five, which is more pristine, having no human modification. To measure the effects of human activity on the biota of each lake, modern communities were assessed and sediment cores were collected to test if there were significant biotic differences with respect to these two different blue holes. Both lakes contain similar algal, fish, and mollusk communities but somewhat different surrounding vegetation.

Sediment cores from both blue holes contained high abundances of ostracodes and mollusks. Ostracode assemblages changed over time in response to salinity, with climate changes broadly synchronous between the two blue holes. Initial core descriptions revealed that the concentration of mollusks in Blue Hole Five cores were significantly greater than that of Watling's Blue Hole cores. Further analysis of mollusks found in Blue Hole Five cores showed four species--Cerithidea costata and Anomalocardia auberiana, with lesser, but significant abundances of Acteocina sp. and Polymesoda maritima. The distribution and diversity of mollusks within these lakes through time likely are related to sea level fluctuations. Further studies are needed to assess the taphonomic controls in these lakes to determine the relative impacts of natural versus anthropogenic change.