EPA funds help Maui find
solutions to seaweed woes
KIHEI, Maui >> Seaweed is a common hidden ingredient in ice cream and luncheon meat. Some people even look for it in vitamin supplements and fancy face creams. But for an increasing number of beachfront neighborhoods and ecosystems, alien seaweeds are unwanted invaders.
Wading through several feet of algae spurred Kihei's Waipuilani Beach community to seek a $250,000 grant from the Environmental Protection Agency to develop an innovative seaweed-removal method, using a modified potato digger.
At Waipuilani, conditions are nearly perfect for seaweed: tradewinds drive it toward the shore, where shallow water, ancient fishponds and a natural coral formation prevent it from drifting away.
Native seaweeds have washed ashore here for much of the last century, at least, but the addition of the nonnative Hypnea musciformis variety has amplified the problem.
The variety more commonly called Hypnea probably leaked into Hawaiian waters in the 1970s after a failed attempt to cultivate it for kappa carrageenan, a gelling agent used in puddings, toothpastes and other products.
Now the variety is among several invasive seaweeds that plague the islands' beaches.
Invasive seaweeds are already well established elsewhere, said Celia Smith, a University of Hawaii botany professor who heads a research lab that is looking into Waipuilani's problem and similar problems in other parts of the world.
Caulerpa taxifolia has been vexing underwater ecosystems in the Mediterranean for about a decade. The robust and fast-growing seaweed has spread to Adriatic coasts, Australia and even California and Florida, annihilating seagrasses and other marine life along the way.
French navy divers have tried pulling it up by hand, and researchers have tried everything from killing it with salt to blocking its sunlight with giant plastic and aluminum tarps.
Waipuilani residents researched seaweed-removal techniques and decided on the modified potato-digging machine to pick up the unwanted beach cover. The county bought the machine, called a "beach master," last year.
"It's not a perfect solution, but it seems to be working pretty good compared to the 'bull dozer,"' said active community member David Mackwell, referring to a souped up Ford 2120 tractor that used to move seaweed (and sand) to one end of the beach.
Now the county plans to use the bulk of Kihei's EPA funds for a truck to haul the seaweed to a composting site. In the past, some of the seaweed has been used for fertilizer or ended up in the county landfill.
It makes economic sense to remove the seaweed from the beach, according to a study last year, which said Waipuilani's seaweed costs the area millions of dollars a year in lower property values. The county collects less property tax revenue and the beach gets less recreational use than others nearby.
But to Smith, whose research focuses on nutrient levels in Kihei's water, simply removing the seaweed doesn't isn't a solution. Increased seaweed is feeding off something in the water, and Smith is trying to find what that nutrient is and why it's there.
"We have to cure the problem," she said. "Trucking stuff away just treats the symptoms."