The nearshore benthic habitat supports 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. State and National agencies have been mandated to preserve and enhance these resources and require detailed habitat characterization in order to do so. The Seafloor Mapping and Benthic Habitat Studies Project of the USGS Western Coastal and Marine Geology Team maps the benthic habitat in areas that have been selected because they have been set aside as National Marine Sanctuaries, National Parks, State Fish Preserves, or are areas of ongoing or planned fish population studies.
Areas mapped around the Northern Channel Islands, to date.
See samples of our maps on the Seafloor Mapping web pages.
Accurate base maps are a prerequisite for any geological study, regardless of the objectives. Land-based studies commonly utilize aerial photographs, USGS 7.5-minute quadrangle maps, and satellite images as base maps. Until now, studies that involve the ocean floor have been at a disadvantage due to an almost complete lack of accurate marine base maps. Many base maps of the sea floor have been constructed over the past century but with a wide range in navigational and depth accuracies.
Only in the past few years has marine navigational accuracy approached 1 m and depth resolution 50 cm. We use state-of-the-art digital multibeam systems to systematically map the seafloor. The two types of data collected include bathymetry (seafloor depth) and backscatter (data that can provide insight into the geologic makeup of the seafloor). These data are of critical importance to groups as diverse as marine habitat biologists, state and local authorities setting regulations on seafloor uses, school children, and teachers. The new high-resolution base maps will be used for:
Ongoing research is attempting to derive better relationships between the backscatter collected from a multibeam mapping system and the seafloor geology. The ultimate goal of this research is to convert the backscatter maps into geologic maps.
See samples of our maps on the Seafloor Mapping web pages.
For additional information contact the project coordinator, Guy R. Cochrane.
|
U.S. Department of the Interior | U.S. Geological Survey
URL: http://walrus.wr.usgs.gov/nearshorehab/
Page Contact Information: Laura Zink Torresan
Page Last Modified: 27 June 2008 (lzt)
