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The Honolulu Advertiser
Posted on: Monday, November 7, 2005

HAWAI'I'S ENVIRONMENT
Sea debris shed light on currents

By Jan TenBruggencate
Advertiser Columnist

An informal, small-scale "drifting camera" study of ocean currents, conducted by this writer's beachcombing family, confirms data found by sophisticated scientific surveys: that stuff on the surface can readily float from southeast to northwest up the Hawaiian Island chain.

The survey is a function of the popularity of cheap underwater cameras. Sometimes, tourists lose them in the water and they are thrown to the winds and currents. My family has found three such cameras while beachcombing in recent years, and they were in good enough shape that the photos could be processed.

We weren't able to determine who the cameras belonged to, but we were able in each case to determine that the island where the photos were taken was different from the one where the camera was found, suggesting the cameras had floated from one land mass to the next.

The first camera was found three years ago, drifting in a debris field off East Moloka'i. The images processed from the camera were tourist-type shots from Maui, which is just eight miles across the channel and visible southeast from where the camera was found.

The second camera was found last year on a rocky beach on East Kaua'i, near Lihu'e Airport. The pictures showed shots of O'ahu's north shore, including Waimea Bay, which is also southeast of where the camera was found.

The third camera was picked up last month on a rocky shore on the eastern side of Moloka'i's Makanalua Peninsula. The images were from West Maui. The camera's route would have required an interesting jog to the north through the Pailolo Channel between Maui and Moloka'i, and then east down the north Moloka'i coastline.

Disposable cameras float pretty high in the water, and would be affected by wind and surface currents.

Mark Merrifield, an oceanographer with the University of Hawai'i's School of Ocean and Earth Science and Technology, said there are eddies and hour-by-hour changes in current patterns between the islands, in addition to changing wind directions and speeds.

"Anything partially submerged in the water will certainly be carried along in part by the current, as well as the wind," he said. "There are all sorts of paths for interisland connections."

Merrifield cited a Web site that shows some surface-current predictions from a U.S. Navy current model. Check it out at www7320 .nrlssc.navy.mil/global_ ncom/haw.html.

If you have a question or concern about the Hawaiian environment, drop a note to Jan TenBruggencate at P.O. Box 524, Lihu'e, HI 96766 or jant@honoluluadvertiser.com. Or call him at (808) 245-3074.