![[Skip Navigation]](/images/pixel.gif){kind=tracking}
|
Benthic Habitat Mapping
SummaryThis section highlights three example analyses that provide practical examples of utilization and integration of various data collection, display, and analysis techniques. The first example is a simple case of verifying and interpreting side-scan sonar data. Another example focuses on delineating habitat across broad stretches of the seafloor based on aerial photography. Finally, plan-view photography analysis is described for mapping a seagrass bed. Verifying and Interpreting Side-Scan Sonar Data Sonar data, such as from side-scan or multibeam sonar, is very useful for benthic habitat mapping applications because it can provide 100 percent coverage of the desired area of seafloor. However, the data must be verified to ensure accurate geologic and substrate classification. Direct benthic sampling (using grabs or cores) and bottom photography are useful verification tools. In the bottom cover map below, side-scan sonar data are first used to delineate geologic substrate types. Then sediment profile imagery (SPI) is used at a number of sampling points to verify the side-scan data and further to describe and define substrates. The combined side-scan sonar and SPI data provide a continuous and detailed picture of the seafloor.
Digitizing Habitats from Aerial Photography The National Oceanic and Atmospheric Administration (NOAA) conducted a U.S. Virgin Islands and Puerto Rico Mapping Project to create consistent and comprehensive maps of benthic habitats based on aerial photography. Through visual interpretation of aerial photographs, various habitats were classified and delineated, including coral reefs, seagrass beds, and mangrove forests. Mapping Seagrass Density with Plan-view Photography In 2001, a small eelgrass bed in Narragansett Bay, Rhode Island was mapped to provide baseline data for assessment of impacts from a planned dredging project. The small extent (approximately 1 acre) of this eelgrass bed and turbid water precluded the use of aerial mapping techniques; therefore water-based methods were used. This seagrass mapping example describes how plan-view photography can be analyzed to create a seagrass map for resource management.
|
