Implications for the resilience of modern coastal systems derived from mesoscale barrier dynamics at Fire Island, New York

Earth Surface Dynamics
By: , and 

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Abstract

Understanding the response of coastal barriers to future changes in rates of sea level rise, sediment availability, and storm intensity/frequency is essential for coastal planning, including socioeconomic and ecological management. Identifying drivers of past changes in barrier morphology, as well as barrier sensitivity to these forces, is necessary to accomplish this. Using remote sensing, field, and laboratory analyses, we reconstruct the mesoscale (decades–centuries) evolution of central Fire Island, a portion of a 50 km barrier island fronting Long Island, New York, USA. We find that the configuration of the modern beach and foredune at Fire Island is radically different from the system's relict morphostratigraphy. Central Fire Island is comprised of at least three formerly inlet-divided rotational barriers with distinct subaerial beach and dune–ridge systems that were active prior to the mid-19th century. Varying morphologic states reflected in the relict barriers (e.g., progradational and transgressive) contrast with the modern barrier, which is dominated by a tall and nearly continuous foredune and is relatively static, except for erosion and drowning of its fringing marsh. We suggest that this state shift indicates a transition from a regime dominated by inlet-mediated gradients in alongshore sediment availability to one where human impacts exerted greater influence on island evolution from the late 19th century onward. The retention of some geomorphic capital in Fire Island's relict subaerial features combined with its static nature renders the barrier increasingly susceptible to narrowing and passive submergence. This may lead to an abrupt geomorphic state shift in the future, a veiled vulnerability that may also exist in other stabilized barriers.

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Publication type Article
Publication Subtype Journal Article
Title Implications for the resilience of modern coastal systems derived from mesoscale barrier dynamics at Fire Island, New York
Series title Earth Surface Dynamics
DOI 10.5194/esurf-12-449-2024
Volume 12
Issue 2
Year Published 2024
Language English
Publisher European Geosciences Union
Contributing office(s) St. Petersburg Coastal and Marine Science Center
Description 27 p.
First page 449
Last page 475
Country United States
State New York
Other Geospatial Fire Island
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