5. Geologic Investigations of the Processes Controlling Northern Gulf of Mexico Coastal Change

Most recently in a long history of storm impacts, several large hurricanes, notably Hurricanes Katrina and Rita in 2005, decimated large sections of the northern Gulf of Mexico coastal system. How the coastal systems will recover from these storms has broad implications to the barrier islands, estuaries, and wetlands of the area, as well as the safety of the human infrastructure along this coast. Additionally, understanding the potential future evolution of this coastal system under climate-change conditions, parts of which are subjected to unusually high rates (~1cm/yr) of relative sea level rise, will provide insight into the response of coastal systems in other regions of the United States to predicted accelerated sea-level rise in the future.

The northern Gulf of Mexico coastal system, in particular the coastline between Florida and Texas, contains a variety of geomorphologic environments resulting from complex geologic processes. Aside from the dominant Mississippi River Delta, these environments also include barrier islands and spits, tidal inlets, wetlands, deltaic headlands, Pleistocene terraces, and offshore shoals and marine sand bodies. The shoreline features are backed by narrow bays, large estuarine basins and fresh or saline wetlands. The response of these environments to sea-level rise, land subsidence, changes in sediment budgets, and storm impact are not well understood. In addition, the control of the underlying framework geology on geomorphic expression of coastal and offshore features is of interest but largely unknown.

There is a broad suite of research questions that would be appropriate to address; this position will focus on applying research to marine and coastal geology issues. Addressing these questions will help improve our understanding of the future evolution of this coastal system:

1. where did the sand from the barrier islands go during Hurricane Katrina (that is, the need to develop a quantitative, or semi-quantitative sediment budget)?
2. how has the coast changed since Katrina (that is, are there signs of recovery or further deterioration)?
3. what natural processes are acting on this area and are they leading to further deterioration or rebuilding of the coast?
4. how are modern modifications (beach renourishments, channel dredging, and so on) impacting natural coastal evolution?
5. on the basis of a short-term study, can we predict the future of this coastal system and perhaps extrapolate the results to other barrier systems?

While proposals focused on relevant processes will be considered, there are two particularly outstanding opportunities that would capitalize on recently acquired data sets from this region: (1) coastal change along the northern Gulf of Mexico barrier islands and near shelf region and (2) the bathymetric and topographic response of sections of the Gulf Coast to storm impact.

The primary objective of this research opportunity will be to work with a team of researcher geologists and oceanographers to determine the dominant processes that have resulted in observed coastal response. Postdoctoral research should result in a geomorphologic characterization for the complex nearshore, establishing the regional landscape evolution, and characterizing the processes that drive coastal change. This information will contribute to our understanding of coastal response to changing climatic conditions, sediment supply and transport, and regional land subsidence, all important parameters in modeling future coastal response. Activities planned to reach this objective will include working with a team to measure bathymetry and subottom stratigraphy (geophysical surveys), topography (using LIDAR), land subsidence (in situ using SET’s or remotely using inSAR data), sea level change (modeling) and storm impacts on the northern Gulf Coast (direct observations pre and post storms). To attain this objective, it will be necessary to quantify coastal processes that contribute to shoreline evolution, and determine the bathymetric and topographic response to Holocene sea level rise, land subsidence, and storm impact in the northern Gulf of Mexico.

The postdoctoral researcher will be at the forefront of coastal landscape evolution and coastal change research in the United States, and will participate in significantly improving our understanding of some of the most important and societal-relevant issues faced by the USGS. The postdoctoral fellow will have ample opportunities for interdisciplinary collaborations in geology, oceanography, data analyses, numerical modeling, and remote sensing.

Reference

U.S. Geological Survey, 2003, A plan for a comprehensive National Coastal Program, report requested by Congress, 42 p.

Proposed Duty Station: St. Petersburg, FL or Woods Hole, MA

Areas of Ph.D.: Geology, geophysics, geological oceanography

Qualifications: Applicants must meet one of the following qualifications: Research Geologist, Research Oceanographer

(This type of research is performed by those who have backgrounds for the occupations stated above. However, other titles may be applicable depending on the applicant's background, education, and research proposal. The final classification of the position will be made by the Human Resources specialist.)

Research Advisor(s): James Flocks, (727) 803-8747 x3012, jflocks@usgs.gov; S. Jeffress Williams, (508) 457-2383, jwilliams@usgs.gov; Dawn Lavoie, (225) 665-6310, dlavoie@usgs.gov; Shea Penland, (University of New Orleans, spenland@uno.edu; Mark Kulp, University of New Orleans, mkulp@uno.edu

Human Resources Office contact: Kathy McDuffie, (703) 648-7408, kmcduffie@usgs.gov

Summary of Opportunities