RAPID: Disentangling the sedimentary storm signal in coastal submarine caves and ponds in Bermuda with implications for the entire North Atlantic Basin
Uncertainty in the timing of major storm events in the Atlantic Ocean, some of which have devastating impacts on infrastructure along the east coast of the United States, is a major hindrance in our ability to adequately understand, plan, and possibly mitigate the negative effects of future major storm events especially now that the ocean is documented to be warming and sea level along the east coast is documented to be rising. Much of what we know about the prehistoric record of ocean storm events, like hurricanes or like Super Storm Sandy, come from the sedimentary record in coastal lakes, lagoons, and other places where sediments are transported and deposited. Due to erosion by subsequent events or the mixing of sediments by organisms that live in coastal regions or in the sediments themselves, sometimes these records are hard to date and read due to disruption of characteristic sedimentary features or chemical indicators, like organic detritus and chemical or physical indicators of the timing of the deposit. As a result, this research, funded by a RAPID award, seeks to take samples from ponds and submarine caves on the island of Bermuda to examine fresh, unaltered sedimentary deposits left by category 3 Hurricane Gonzalo which struck the island on October 18, 2014 causing hundreds of millions of dollars in damage. This award funds the research of two early career faculty members, one from Texas A&M University and one from the University of Southern Mississippi to collect cores of fresh sedimentary material on Bermuda that is related to Hurricane Gonzalo and analyze samples using various isotopes (13C, 7Be, 137Cs) that will allow the determination of the origin of any organic matter and allow the deposits to be accurately dated. The study will also measure various sediment physical properties (e.g., particle size, weight percent organic matter) and carry out X-ray Fluoresence (XRF) scanning of the cores, which will enable studies of sedimentary structures that indicate the rates and processes of sediment deposition. Results of the investigation will be compared to older sedimentary records collected by these investigators in the same locations over the past six years. The fresh sediments will be used to help calibrate the older records and help the investigators distinguish between simple storminess records and major hurricane events.Broader impacts of the work are significant. Societal impacts include an improvement of our understanding of the timing and intensity of mid-Atlantic storm and hurricane records, a number of which originate in the tropics; travel north over the ocean; and then curve eastward wreaking major damage on western Europe coastal and inland communities. The research also has the potential to resolve the disparity of interpretations of prehistoric Bermudian storm records, which are important for understanding tropical hurricane frequency that impacts communities and infrastructure on the US eastern seaboard. Additional impacts include the funding of two early career scientists, one of whom is at an institution in an EPSCoR state (Mississippi). There will also be training of undergraduate and graduate students, some of whom are from a gender under-represented in the geological science. These students will be engaged in analyzing samples and comparing them with previously collected sedimentary records. In addition, the lead investigator will organize a local symposium in Bermuda to engage local stakeholders in the research program.