History of S. RI Methods
Data & Results
Publications
Bibliography
Links
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Mapping
Side-scan Sonar Mapping The first mapping was done in 1999 using a Datasonics SIS-1000 Seafloor Imaging System at 100kHz. This resolution was not adequate to identify eelgrass beds, so a second survey was done in the fall of 2002 with an Edgetech DF-1000 Sidescan Sonar Towfish at 500kHz.  |
Grain Size Surface grab samples (0-2 cm) were analyzed for grain size (sand-silt-clay content). They were first treated with acid to remove carbonates, then hydrogen peroxide to remove organic material. They were rinsede through a 63um seive and analyzed using an Elzone particle analyzer. |
Groundtruthing In order to definitively identify and record the habitats of the lagoon, the sidescan sonar map was groundtruthed using an Applied Microvideo M-200 underwater video camera. The navigation was stamped on the video recording using a Sea Trak GPS video overlay system. The habitat was defined approximately every minute in the video and entered into a database with the location. All of the points were entered into the GPS, coded based on habitat type, and overlain on the side-scan map. |