Olympic Coast National Marine Sanctuary Science section includes Seafloor Mapping, Oceanography, Deep Sea Coral and Sponges, Wildlife Research, Coastal Habitats, Citizen Science, Ecosystem Processes, Research Surveys, and Research Assets
Olympic Coast National Marine Sanctuary Science section includes Seafloor Mapping, Oceanography, Deep Sea Coral and Sponges, Wildlife Research, Coastal Habitats, Citizen Science, Ecosystem Processes, Research Surveys, and Research Assets
Olympic Coast National Marine Sanctuary Science section includes Seafloor Mapping, Oceanography, Deep Sea Coral and Sponges, Wildlife Research, Coastal Habitats, Citizen Science, Ecosystem Processes, Research Surveys, and Research Assets Olympic Coast National Marine Sanctuary Science section includes Seafloor Mapping, Oceanography, Deep Sea Coral and Sponges, Wildlife Research, Coastal Habitats, Citizen Science, Ecosystem Processes, Research Surveys, and Research Assets

Seafloor Habitat Mapping
Data Classification

Seafloor habitat classification systems are designed to describe the ocean floor and categorize it for broader application. Olympic Coast National Marine Sanctuary uses the "Deep-Water Marine Benthic Habitat Classification Scheme" which was created to easily distinguish seafloor habitats types and make it easier to analyze and generate reports using GIS, database, and spreadsheet software programs. The classification system provides codes for each of seven categories determined by remote sensing and three additional categories determined from video, still photos or direct observations. These ten components can be used to define habitats across spatial scales or to compare habitat types.

Close-up photo of boulders with attached sessile organisms

A sample site interpreted using the Deep-Water Marine Benthic Habitat Classification Scheme. The coded charactarization for GIS-related applications would read S h(bc)b 1 C: A hard substrate (h) with a biomodal (b) distribution of sediments - specifically boulder and cobble (bc), found on a flat slope (1) on the Shelf (S) and having a high XYZ complexity when compared statistically with its areal neighbors.

At the broadest scale megahabitat defines the depth and physiographic boundaries of a unique habitat on a scale of 10s of kilometers. Seafloor induration refers to substrate hardness, where hard, soft and mixed substrate can then be further subdivided into distinct sediment types. At a finer scale, meso/macrohabitat denotes areas in depth or physiographic uniqueness less than a kilometer in scale. Texture is an important seafloor characteristic that describes the nature of seabed such as the relief or level of erosion. Slope is calculated from x-y-z multibeam data and is coded in categories ranging from flat ocean bottom to overhanging rocky ledges. Seafloor complexity is derived from derived from slope data in a GIS program using neighborhood statistics. When the geologic unit is known, it is added to the classification code.

From groundtruthing data, additional codes can be added to the habitat classification structure. To inform a macro/microhabitat data layer, geologic attributes such as sediment grain size (e.g. boulder, cobble, sand) and biological inclusions (e.g. algae, corals, anemones) can be plotted. Micro scale seafloor slope may be groundtruthed to validate the classification. Finally,micro scale seafloor complexity is based on seafloor rugosity values taken along a transect.

Map of the area which has already been classified in the sanctuary

OCNMS separates its seafloor classification into shelf (browns) which are areas less than 200 meters depth, and flank (blues) which are canyons deeper than 200 meters. Other seafloor habitat characteristics are subset within these megahabitats.

Approximately 1,461 square km (425.99 sq nm) of OCNMS has been classified for seafloor habitat. At its simplest, the seafloor data can be viewed in a GIS program as hard substrate, soft substrate, or mixed hard/soft substrate. Other characterization details are available depending on the year of the data, the type of survey that was conducted, and they type of sonar that was used.



Contact for page content: Nancy Wright
photo of a buoy on the ocean
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