Posted on: Tuesday, February 15, 2005
Divers prepare to map seafloor
By Jan TenBruggencate
Advertiser Science Writer
Teams of divers will use specialized seafloor mapping techniques today to assess the reef damage caused by the Feb. 2 grounding of the 555-foot bulk carrier Cape Flattery.
Researchers also are consulting with scientists from as far away as the East Coast to review techniques for cementing large, living coral heads back to the ocean floor before their coral communities are killed from being buried in sediment or abraded away by rolling around on the reef.
"We've got a lot of work to do," said coral reef specialist Dave Gulko of the state Division of Aquatic Resources.
Marine biologists called on the specialized skills of divers from the National Oceanic and Atmospheric Administration's Pacific Islands Fisheries Science Center to conduct a detailed survey of the reef, covering waters 20 feet to 60 feet deep about a quarter mile off Kalaeloa Barbers Point Harbor.
The Cape Flattery, carrying a load of granular cement, was freed from the reef Friday after most of its fuel and much of its load was removed. Divers in a preliminary survey Friday said they located a significant area of solidified concrete on the surface of the reef, apparently the result of spillage during the offloading operation.
Today's dives will include techniques used by NOAA divers to survey reefs in the Northwestern Hawaiian Islands and elsewhere in the Pacific.
"They'll be using our towed-diver fish and habitat survey protocol," said Rusty Brainard, head of the Pacific Islands Fisheries Science Center.
Dive teams were scrambling yesterday to get ready for today's dives. "Normally we have months to prepare for these surveys," said center marine ecologist Jean Kenyon.
She said each team normally includes two divers, referred to as the "bottom diver" and the "fish diver." They dive in 50-minute segments.
The bottom diver is towed with a board held about one meter above the ocean floor. The board is equipped with a camera that automatically takes a digital image of the bottom every 15 seconds. Every five minutes, the diver records on a data sheet a description of various features of the ocean floor.
The fish diver, being towed at the same time, uses a forward-facing video camera, and makes notes on the presence of larger fish.
Kenyon said there would be two teams of survey divers, and that they would cruise the reef in a back-and-forth "lawnmower pattern."
"The images provide a lot of data in a short period of time," Kenyon said.
The other crisis is to save some of the large coral heads that were knocked over during the salvage operation. The coral heads are important mini-habitats for reef life, but they also can become instruments of further damage if they begin rolling around in a large swell.
Researchers in the past have been able to wire smaller corals to the reef and let them reattach themselves. But with big corals, they are hoping for some kind of system that will permanently attach them to the reef so they grow in one place and can't roll away.
"I think they're looking at techniques for epoxying of damaged coral heads back on the reef," Kenyon said.
Reach Jan TenBruggencate at jant@honoluluadvertiser.com or (808) 245-3074.
