Publications

In July (19 - 26) and November (17 - 18) of 1999, the USGS, in cooperation with the Florida Geological Survey (FGS), conducted two geophysical surveys in: (1) the Atlantic Ocean offshore of Florida's east coast from Orchid to Jupiter, FL, and (2) the Gulf of Mexico offshore of Venice, FL. This report serves as an archive of unprocessed digital boomer subbottom data, trackline maps...

From June 3 to 13, 2011, the U.S. Geological Survey conducted a geophysical survey to investigate the geologic controls on barrier island framework and long-term sediment transport along the oil spill mitigation sand berm constructed at the north end and just offshore of the Chandeleur Islands, LA. This effort is part of a broader USGS study, which seeks to better understand barrier...

The aim of this study is to improve estimates of wetland land loss in two study regions of coastal Louisiana, U.S.A., due to the extreme storms that impacted the region between 2004 and 2009. The estimates are based on change-detection-mapping analysis that incorporates pre and postlandfall (Hurricanes Katrina, Rita, Gustav, and Ike) fractional-water classifications using a combination...

Colonies of three coral species, Montastraea faveolata, Diploria strigosa, and Siderastrea siderea, located in the Dry Tortugas National Park (DRTO), Florida, were sampled and analyzed to evaluate annual linear extension rates. Montastraea faveolata had the highest average linear extension and variability in (DRTO: C2 = 0.67 centimeters/year (cm yr-1) ± 0.04, B3 = 0.85 cm yr-1 ± 0.07)...

Coral reefs are degrading on a global scale, and rates of reef-organism calcification are predicted to decline due to ocean warming and acidification. Systematic measurements of calcification over space and time are necessary to detect change resulting from environmental stressors. We established a network of calcification monitoring stations at four managed reefs along the outer Florida...

U.S. Geological Survey (USGS) scientists have provided a model-based assessment of transport and deposition of residual Deepwater Horizon oil along the shoreline within the northern Gulf of Mexico in the form of mixtures of sand and weathered oil, known as surface residual balls (SRBs). The results of this USGS research, in combination with results from other components of the overall...

Beaches serve as a natural barrier between the ocean and inland communities, ecosystems, and natural resources. However, these dynamic environments move and change in response to winds, waves, and currents. During extreme storms, changes to beaches can be large, and the results are sometimes catastrophic. Lives may be lost, communities destroyed, and millions of dollars spent on...

Beaches serve as a natural buffer between the ocean and inland communities, ecosystems, and natural resources. However, these dynamic environments move and change in response to winds, waves, and currents. During extreme storms, changes to beaches can be large, and the results are sometimes catastrophic. Lives may be lost, communities destroyed, and millions of dollars spent on...

The coastal region of the northern Gulf of Mexico owes its current landscape structure to an array of tectonic, erosional and depositional, climatic, geochemical, hydrological, ecological, and human processes that have resulted in some of the world's most complex, dynamic, productive, and threatened ecosystems. Catastrophic hurricane landfalls, ongoing subsidence and erosion exacerbated...

A three-dimensional groundwater-flow model was developed for Assateague Island in eastern Maryland and Virginia to simulate both groundwater flow and solute (salt) transport to evaluate the groundwater system response to sea-level rise. The model was constructed using geologic and spatial information to represent the island geometry, boundaries, and physical properties and was calibrated...

The demography, spatial distribution, and movement patterns of leopard sharks (Triakis semifasciata) aggregating near the head of a submarine canyon in La Jolla, California, USA, were investigated to resolve the causal explanations for this and similar shark aggregations. All sharks sampled from the aggregation site (n=140) were sexually mature and 97.1 % were female. Aerial photographs...

Carbon dioxide (CO2) in the atmosphere is absorbed at the surface of the ocean by reacting with seawater to form carbonic acid, a weak, naturally occurring acid. As atmospheric carbon dioxide increases, the concentration of carbonic acid in seawater also increases, causing a decrease in ocean pH and carbonate mineral saturation states, a process known as ocean acidification. The oceans...