Doctoral Dissertation Research: Multi-Proxy Paleoecological Records from the Shark River Estuary: Wetland Evolution in the Light of Paleohurricane Activity and Sea-Level Changes

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This doctoral dissertation research project will examine the long-term response of coastal wetland communities to past sea-level fluctuations and recurrent hurricane strikes to reveal the Holocene history of mangrove forests in the Everglades of southwestern Florida. No palynological record older than 5,000 years before the present currently exists for this region. The doctoral student will help fill this gap by integrating various paleoecological methods including palynological, x-ray fluorescence, and loss-on-ignition analyses to produce the first pollen record and paleo-hurricane proxy record over the past 7,500 years and reveal the oldest depositional history of the coastal Everglades. Radioactive isotope analyses of 14-carbon, 137-cesium, and 210-lead will be used to date sediment samples collected from locations along and near the Shark River Slough. Analyses of a sediment core previously collected at the mouth of the Shark River Slough had identified a distinctive stratigraphic signature for Hurricane Wilma, an intense hurricane that directly struck the study area in 2005. This storm deposit will be used as a modern analog for identifying other hurricane events in other cores. Analyses of these cores and the resulting vegetation chronologies that will be produced should help reveal the response of mangrove forests to past sea-level rise and hurricane disturbance.Coastal mangrove forests in the Everglades are an important natural resource. By coupling palynology with paleotempestology, the results of this study will shed light on the response of the mangrove ecosystem to multiple extreme events over timescales of centuries to millennia. Such a database addresses two key issues in the management and restoration of the Everglades coastal ecosystems: rapid sea-level rise and extreme hurricane disturbances. The palynological results will provide guidelines and background knowledge for management planning for coastal protection and restoration. This project also should help identify the frequency of catastrophic hurricanes in South Florida, which is information vital for risk assessment and disaster management in the region. As a Doctoral Dissertation Research Improvement award, this project will provide support to enable a promising student to establish an independent research career.