The use of coastal lagoon sediments to track the long-term hurricane history of Jamaica, West Indies
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Long-term data are needed to properly assess the influence of anthropogenic climate change on Atlantic hurricane frequency, however hurricane records are inconsistent prior to the development of modern monitoring techniques. Paleolimnological investigations from coastal Caribbean lagoons can be used to track changes in Atlantic hurricane activity because coastal lagoons can become inundated with seawater during hurricane events, which leaves distinct biological and geochemical signals in their sediments. This study analyzes changes in fossil diatom assemblages and chlorophyll-a (chl-a) concentrations of a ~1,500 year old sediment core from Grape Tree Pond, a coastal lagoon located in southern Jamaica. The diatom and chl-a profiles were used to evaluate overall changes in salinity and primary production, as well as to identify potential periods of enhanced hurricane activity. The results of this research identified three periods of pronounced hurricane activity around 1350, 1725-1785, and 1900-1925 CE, which were indicated by mixed-salinity diatom assemblages and distinct changes in chl-a concentrations. Additionally, two periods of drought occurring during 1650-1725 and ~1785-1900 were identified by low diatom abundance and decreased chl-a concentrations. These changes in the diatom assemblage and chl-a concentrations show that climate variability has increased following the onset of the Little Ice Age (~1450-1850 CE), however it is difficult to distinguish the impacts of recent anthropogenic climate warming on hurricane activity from those of natural Atlantic climate regimes, such as ENSO. This study is one of the first to report on the diatom species found in Jamaica, and demonstrates the potential of using fossil diatoms from coastal lagoons to track past storm activity.