Past Sea Level & Climate Change during a Critical Time Period from Broward County

Grant Winners

Dean

Abstract

Of the many profound and contentious consequences Greenhouse warming poses, sea-level rise and large-scale coastal flooding will have the greatest impact on societies globally. There has been considerable debate as to the nature and magnitude of sea-level rise in the near future, but also in the recent past, since the last ice age (last 11,000 years). Specifically, the debate centers on whether changes in past sea-level position occurred in rapid meter-scale jumps or a general smooth rise. Evidence for both exists, however no clear defining trend has been totally resolved. It is therefore of importance to understand how changes in sea level actually occurred in the recent past during a time period of changing climatic conditions in order to gain an understanding of how it may act in the near future. The coral reefs of Broward County Florida are ideally poised to test these ideas since they were actively growing during this critical time period, and were also the basis of the argument for the rapid jumps in sea level. Our recent studies regarding the internal composition and geomorphology of the Broward County reefs revealed that potentially significant altered environmental conditions did occur, but for reasons still largely unknown. We propose to conduct intensive laboratory analyses of previously retrieved reef core coral material in order to constrain the rates of sea-level rise as well as the proxy environmental conditions during this time period of reef growth. This will be accomplished using newly obtained radiocarbon ages and geochemical isotope chronologies produced from coral sample material already in possession. These new analyses yield the potential to provide a better understanding of the environmental conditions that operated during that time, including changes in sea-level as well as significant climatic excursions.