Seafloor Habitats and Mapping
The sanctuary seafloor is a rich and varied component of the marine ecosystem.
The glacial landscape that has been submerged for the last 10,000 years contains
deeply eroded canyons, rocky shorelines and scattered boulders, along with glacial
ridges and vast uninterrupted sandy plains. Each of these habitats has combined with
oceanographic conditions to foster its own diverse array of plants and animals that
contribute to the complexity of the ocean's vast ecological community. Seafloor
mapping allows us to explore this world.
The Washington State Outer Coast Seafloor Atlas
shows the primary surficial substrate types from the shoreline to 700 fathoms.
Take a closer look
View and/or download a high resolution PDF version of each page of the atlas by clicking
on its corresponding map grid rectangle below.
You can also download the
entire high resolution Map Atlas
Download the Washington State Seafloor Atlas map package
The Seafloor Atlas is a combination of two Washington Outer Coast Seafloor maps:
- The Olympic Coast Sanctuary Seafloor Mapping Data: A fine-scale map from OCNMS based on 35 multibeam and sidescan sonar surveys conducted from 2000 to 2013 in the northern sanctuary - re-processed and re-imaged by the Oregon State University Active Techtonics & Seafloor Mapping Lab (AT&SML) in 2015; and
- The Surficial Geologic Habitat Map V4, produced by OSU Active Tectonics & Seafloor Mapping Lab: A coarser-scale composite of seafloor substrate types from multiple sources including sonar surveys, sediment samples, seismic reflection profiles, and video images.
The substrate types from both fine and coarser scale substrate data have been classified using NOAA’s Coastal and Marine Ecological Classification Standard (CMECS). This classification structure provides a framework for organizing information about coasts and oceans and their living systems, including the physical, biological, and chemical data that are used to define ecosystems. The Substrate Component applied in the Atlas identifies the non-living seafloor material that forms an aquatic bottom to provide for growth for attached biota. It creates the context and setting for vital benthic aquatic processes.
Mapped seafloor sediments around Cape Flattery and Tatoosh Island, WA are the result of several types of technology and analytical disciplines.
Seafloor maps also allow OCNMS to support management, research, monitoring and education initiatives.
However, a map of the ocean floor is more than an image – it’s the result of several processes that include:
- Identifying and delineating seabed features captured through remote sensing, usually sonar or lidar;
- Groundtruthing or assessing the signature of the remotely sensed data using video or hands-on sediment analysis;
- Determining Benthic Sediment Types by their grain size and texture across the mapped and groundtruthed area;
- Characterizing the data according to a known Classification System so that it can be understood and shared with others;
- Writing metadata – the documentation that describes how the data were collected, processed and assessed – the final, essential component.
Multibeam image from 15 m seafloor in Makah Bay, WA shows complex benthic substrate.
Seafloor mapping is a priority of OCNMS. Since 2000 the sanctuary has mapped more than 3116 km2
(908 sq nautical miles) of the seabed, focusing on the area from the Juan de Fuca Canyon to Cape Alava
- roughly 37.7 percent of the sanctuary. Part of that area was mapped with sidescan sonar, producing a
seafloor image with a sediment reflection, and part was mapped with multibeam sonar, producing an
image with bathymetry and backscatter. In 2011 OCNMS mounted a multibeam sonar on its research vessel,
the R/V Tatoosh. With that dedicated technology, the sanctuary is now able to map the
remaining area of OCNMS and special features such as shipwrecks,
mooring sites and unique resources.
Contact for page content: Nancy Wright