Researchers embark on mission to fill in gaps in data of seafloor depths around O`ahu

By John Rooney

Today, members of the benthic habitat mapping team of the PIFSC Coral Reef Ecosystem Division (CRED) and other CRED staff began a 3-week mission (SB-13-11) to survey around the island of O`ahu with a NOAA survey launch, the 8-m R/V AHI. Equipped with a 240-kHz Reson SeaBat 8101 ER multibeam echosounder and associated equipment, the R/V AHI has been used to collect seafloor depth data, or bathymetry, around many of the islands in the main and Northwestern Hawaiian Islands, American Samoa, the Pacific Remote Island Areas (Palmyra, Johnston, and  Wake Atolls, Howland, Baker, and Jarvis Islands, and Kingman Reef), and the Mariana Archipelago (Guam and the Commonwealth of the Northern Mariana Islands).

The NOAA R/V AHI, an 8-m survey launch, will be used to map seafloor depths around O`ahu from June 17 to July 3. NOAA photo

The NOAA R/V AHI, an 8-m survey launch equipped with a multibeam sonar, will be used to map seafloor depths around O`ahu from June 17 to July 3. NOAA photo

Funded by NOAA’s Coral Reef Conservation Program, the purpose of this survey mission is to fill gaps in existing high-resolution bathymetry around O`ahu. Large research ships, such as the R/V Kilo Moana, operated by the University of Hawai`i at Mānoa, or the NOAA Ship Hi`ialakai have collected bathymetry data in waters deeper than 200 m (600 ft) around the islands of the Hawaiian Archipelago, but they are unable to safely navigate close to shore, where most reef ecosystems are found. A small boat, the R/V AHI, then, is an ideal craft for this purpose. Data that CRED has collected with her have been used for a wide variety of resource management tasks, such as designing ecological monitoring, designing routes for subsea pipelines and cables to avoid coral-rich areas, and selecting anchorage areas that will minimize effects to coral reefs.

If weather conditions during the survey period are favorable, the CRED staff on this mission—Frances Lichowski, Jeremy Taylor, John Rooney, Kevin O’Brien, and Faith Knighton—should be able to fill in all the gaps in the existing bathymetry coverage around the island of O`ahu at depths shallower than approximately 200 m (660 ft). Processing the data will take another 6 months or so of time in the laboratory. The processed data will be provided to partners at the Hawaii Mapping Research Group (HMRG) in the School of Ocean and Earth Science and Technology at the University of Hawai`i at Mānoa. The new bathymetry data will become part of a synthesis of high-resolution bathymetry data around the main Hawaiian Islands that HMRG maintains and makes available for download. The processed data also will be provided to NOAA’s National Geophysical Data Center, which also maintains a website where bathymetry data can be downloaded.

The small white areas within the purple-colored band that surrounds the island of O`ahu in this map indicate gaps in the existing coverage of high-resolution bathymetry on the western, northern, and eastern sides of this island. Weather permitting, the current survey mission will fill all of those gaps at depths shallower than about 200 m (660 ft).

The small white areas within the purple-colored band that surrounds the island of O`ahu in this map indicate gaps in the existing coverage of high-resolution bathymetry on the western, northern, and eastern sides of this island. Weather permitting, the current survey mission will fill all of those gaps at depths shallower than about 200 m (660 ft).

This entry was posted in coral reef ecosystem and tagged , , , , , , , , , , , , , , , , , , , , , , , , . Bookmark the permalink.