Benthic Habitat Classification and 3-D Visualizations, Derived from Acoustic Multibeam Data, for Vatia Bay, American Samoa

2004 Association of American Geographers Centennial Meeting
Philadelphia

SPECIAL SESSION: GIS in Marine and Coastal Environments

R Rinehart

Dept of Geosciences, Oregon State Univ

Corvallis, OR 97331-5506

541-737-8818

D Wright

Dept of Geosciences, Oregon State Univ

Corvallis, OR 97331-5506

This study classifies the benthic zones and benthic habitats in Vatia Bay, American Samoa, based on multibeam bathymetry. The goal of this analysis is to contribute to the benthic habitat classification system being drafted by the National Oceanic and Atmospheric Administration's Coral Reef Ecosystem Investigation Task Force. Additionally, the results of this analysis will contribute to the broader resource management and conservation goals of the National Park of American Samoa, as well as the American Samoa GIS User Group. GIS analyses for benthic zones and benthic habitats will consider slope, aspect, rugosity, bathymetry, viewshed and topographic position index as factors. These analyses are combined with multiple 3-D visualizations to produce the first ever benthic zone and habitat maps for this part of the territory. Benthic zones and benthic habitats are differentiated by their resolution and scale. Benthic zones are larger, coarse resolution areas while benthic habitats are fine resolution regions that occur within benthic zones. Benthic zones are derived from bathymetry, slope and topographic position index. They are coupled with rugosity, aspect and viewsheds to produce the more detailed benthic habitat maps. The detailed multibeam data used to formulate the draft benthic habitat characterization zones that will be ground-truthed by upcoming submersible dives. Furthermore, these zones will be compared with a Ikonos-derived benthic classification scheme, also under draft by NOAA, for shallow, nearshore habitats.

Keywords: coastal/marine GIS, benthic habitat, coral reefs, seafloor mapping

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