Benthic Habitat Maps for Rose Atoll Marine National Monument in American Samoa from 2004 to 2010

Benthic habitat maps for Rose Atoll, American Samoa were derived from high resolution, multispectral satellite imagery for 2004, 2006, and 2010. The benthic habitat maps for 2004 were previously generated by NOAA's NCCOS's BioGeography Branch before this project, and they were gathered from NOAA's 2005 publication (NCCOS, 2005). The benthic habitat maps for 2006 and 2010 were generated in this project. Bathymetry (water depth) from 0 to 30 meters was derived from satellite imagery for 2006 and 2010 and validated with multibeam and singlebeam depth data, respectively. Eight geomorphological features of the seafloor (Mean Depth, Standard Deviation of Depth, Slope, Slope of Slope, Rugosity, Curvature, Plan Curvature, and Profile Curvature) were derived from the bathymetry for 2006 and 2010. The geomorphological features were used to perform a Principal Component Analysis (PCA), and the first three Principal Components were used in combination with classified benthic imagery (underwater images of the seafloor) to classify the underwater habitat of the inner lagoon and sloping reef areas of Rose Atoll.

The final benthic habitat maps consist of two maps for each of the three years. The first map shows the four dominant cover types that make up the shallow water benthic habitat on Rose Atoll, which are coral, coralline algae, macroalgae, and turf algae. The area in square kilometers of each cover types is provided. The purpose of the first map is to show the most abundant biological cover types in the benthic habitat. The second map show the percentages of the four dominant cover types, which are divided into three bins: 10%-<50% coverage, 50%-<90% coverage, and 90%-100% coverage. The area in square kilometers of each of the cover types is also provided. The purpose of the second map is to examine the smaller changes in the benthic habitat over the three years.