Determining the Geologic Controls on Coastal and Marine Habitats: Ecosystem Interactions

Assessing Coral Reef Health in Biscayne National Park

Pictured above: Submersible Habitat for Analyzing Reef Quality (SHARQ).

Biscayne National Park, Florida, encompasses a marine coastal environment characterized by coral reefs, mangrove islands, sea grass beds, and a variety of other tropical marine benthic (sea-floor) habitats. The close proximity of BNP to a major metropolitan area and agricultural region has raised concern for the health of this marine resource.

USGS scientists Kim Yates, Bob Halley, Phil Thompson, and Alex Moomaw have been monitoring rates of key metabolic processes such as calcification, photosynthesis, and respiration (collectively termed productivity) as a method for quantifying reef health in terms of system functionality. This enables geographic comparisons of system health between different reef environments.

Productivity rates associated with representative benthic habitats in Biscayne NP were measured using the Submersible Habitat for Analyzing Reef Quality (SHARQ), a large incubation chamber invented by Yates and Halley. The large surface area and water volume isolated by the SHARQ enables 24-hour, community-level productivity measurements for several substrate types including live rock, coral and coral rubble, live sand, and sea grass communities.

Pictured above: A specialized underwater microphone monitors the natural sounds of a reef.

A cooperative NPS and USGS study led by Gary Hill of the USGS St. Petersburg Field Center focuses on evaluating the use of "reef sounds" (passive acoustic emissions monitoring) to map reefs thematically, identify reef processes, and assess reef health quantitatively. In the photograph above, a hydrophone, located in the center of a parabolic dish, captures sounds made by the star coral Montastrea annularis and other reef sounds made by biologic, geologic, hydrologic processes.

Assessing Physical Characteristics of Near Shore Benthic Habitats

Geophysical surveys can provide information about the physical characteristics of near shore benthic habitats that support a diversity of marine life that are commercially, recreationally, and intrinsically valuable. Some of these resources are known to be endangered including species of rockfish and shellfish. Recent and current studies include surveys of the sea floor at Channel Islands National Park, California and Glacier Bay National Park and Preserve, Alaska.

Pictured above: Map of Anacapa Reserve, Channel Islands NP. Geophysical surveys of the sea floor help to identify the characteristics of the sea bottom.

Pictured above: Section of side scan and sub-bottom profiler data from 1998 Channel Islands survey north of Anacapa Island. The side scan image of the surface shows circular rock outcrops (dark gray areas), surrounded by sandy areas (medium gray).

Pictured above: Glacier Bay National Park and Preserve, Alaska: A side-scan sonar image showing "pits", apparently resting places for male crabs. Pits are several meters wide. (Picture taken in 1996).

Investigating Horse-Grazing Impacts on Assateague Island Using Airborne LIDAR Surveys

Pictured above: The feral horses of Assateague Island grazing on dune vegetation.

The U.S. Geological Survey (USGS), National Park Service (NPS), and National Aeronautics and Space Administration (NASA) are jointly investigating horse-grazing impacts on American beach grass and resulting effects on natural dune establishment along Assateague Island National Seashore.

American beach grass is a pioneer dune-building plant as well as a major staple in the feral horse diet at Assateague Island. Using NASA Airborne Topographic Mapper (ATM) elevation surveys, color-infrared photography, and field data, scientists are investigating the changes in topography and vegetation cover in experimental plots to determine the impacts of horse grazing on geomorphology.

Pictured above: USGS scientists assembling a research station at Tomales Bay, Point Reyes National Seashore.

Acquiring Baseline Data for Tidal Marshland Restoration Project at Point Reyes National Seashore, California

Point Reyes National Seashore recently acquired 563 acres of ranch land at the headwaters of Tomales Bay. The National Park Service intends to restore the dairy land to tidal marshland. At present, levees and tide gates prevent tidal incursion and stream flooding. To design a successful wetland, the site has to be surveyed; soil and plant types determined; river, tidal, and meteorological conditions determined; and an integrated model developed. The USGS is collaborating with the National Park Service in the development of high precision surveys of topography, water-level elevations, and wind climate.