Continuous summit-to-sea maps showing both land features and shallow-water coral reefs have been completed in Puerto Rico and the U.S.Virgin Islands,using circa 2000 Landsat 7 Enhanced Thematic Mapper (ETM+)Imagery.Continuous land/sea terrain was mapped by merging Digital Elevation Models (DEM)with satellite-derived bathymetry.Benthic habitat characterizations were created by unsupervised classifications of Landsat imagery clustered using field data,and produced maps with an estimated overall accuracy of >75%(Tau coefficient >0.65).These were merged with Geocover-LC (land use/land cover)data to create continuous land/ sea cover maps.Image pairs from different dates were analyzed using Principle Components Analysis (PCA)in order to detect areas of change in the marine environment over two different time intervals:2000 to 2001,and 1991 to 2003.This activity demonstrates the capabilities of Landsat imagery to produce continuous summit-to-sea maps,as well as detect certain changes in the shallow-water marine environment,providing a valuable tool for efficient coastal zone monitoring and effective management and conservation.

remote sensing; benthic habitats; change analysis; Landsat; coral reefs; mapping