Plankton in 'extreme' bloom

By Jan TenBruggencate
Advertiser Kaua'i Bureau

Passengers flying over the channel between Kaua'i and O'ahu during the past two days may have noticed a lot of brownish scum on the water's surface.

"It was thick, mostly on the Kaua'i side of the channel," said Carolyn Larson, who saw it during a flight Tuesday.

The stuff was washing ashore on Kaua'i yesterday, and biologists identified it as an unusually large bloom of tiny marine creatures, but a natural occurrence.

"There's a tremendous amount of plankton out there," said Don Heacock, a marine biologist with the state Division of Aquatic Resources.

He and a state Department of Health specialist went out by boat to take samples and found that it was a complex array of marine life, including an upper layer of what appear to be reddish-gold diatoms, which are single-celled marine plants.

Beneath them were cone jellyfish, the abandoned shells of tiny marine shrimps and other crustaceans that had molted, and other stuff.

"We've seen this kind of bloom before, but never this extreme," Heacock said.

The stuff may have been highly visible because of calm sea conditions Tuesday.

"If we'd had 30-knot winds, it would have been churned up, and you never would have known about it," Heacock said.

For other forms of marine life, the small marine plants and animals that make up plankton are an important part of the food chain.

"Juvenile tunas and marlin, and the whole food chain would be feeding on this," Heacock said.