Teen Is Tops in Science for Gauging Harm to Seaweed

Sometimes a walk on the beach is not as harmless as it seems.

A talented high school student has won the top honor at the state science fair with a study finding that people who go tide-pooling or rock scrambling along Southern California’s shores might inadvertently be hurting marine life.

Marin McDonald, recently selected Science Student of the Year at the state science fair, spent almost two years studying how humans’ recreational use of the shoreline affects a form of seaweed.

“Human trampling does cause damage,” she said. “People in Southern California have to be more aware of what they’re doing, and should be more ecologically concerned than we are.”

McDonald, 17, studied how people affect a rockweed called Pelvetia compressa. The fleshy brown seaweed anchors itself to rocks, where it can grow knee high, and provides food and a protective habitat for mussels, barnacles and other invertebrates in rocky areas along the shore.

McDonald collected pounds of rockweed at Monarch Bay, Shaw’s Cove in Laguna Beach and Treasure Island in Long Beach, and lugged it back to a laboratory at Cal State Fullerton, where she worked with a team under the guidance of Steven Murray. Murray directs the Coastal Marine Ecology Laboratory, which has special expertise in protected but heavily visited marine environments.

McDonald found that in the areas that offered easier access to people, rockweed was more badly damaged and broken, and had more branches missing.

“She certainly worked hard,” Murray said. And research on the role people play in the reduction of rockweed cover is important, because by altering the size of these plants, they are degrading coastal habitats, he said.

McDonald found that the rockweed was most vulnerable during low tide, when people are more likely to be scrambling over the rocks. The rockweed was least damaged at Monarch Bay, which receives relatively few visitors, she said. Both of the other areas yielded badly damaged seaweed.

But the most degraded spot she saw was in Dana Point, though that site was not included in the study.

“There’s not much rockweed there,” she said. “It’s kind of sad.”

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Another McDonald mentor also praised her work. Robert Phalen, director of the air pollution laboratory at UCI Medical School, is associated with the Southern California Junior Academy of Sciences and had read McDonald’s paper. He was impressed by the results.

Phalen said McDonald’s paper changed the way he thought about coastal plant life.

“It caused me to look at plants in different way. When I now see a plant on the ground, I think of how resistant it is to being stepped on. . . . It elevates the status of plants,” Phalen said.

The findings also changed McDonald’s habits.

“I’ve never been tide-pooling since. I stay on the sand. It’s made me more concerned, and I lecture my friends all the time,” she said.

The California Coastal Act gives the public access to virtually all beach land up to the high tide line, although it prohibits the taking of wildlife from tide pools.

“It’s possible for large numbers of people to visit consistently,” Murray said. “Corona del Mar gets extensive visitation. Visitors put their feet all over the organisms there,” such as seaweed, mussels, sea snails, anemones and tiny hermit crabs.

Murray contrasted the loose regulations at marine areas with management of certain parks, where “we don’t let everybody go wherever they want and just let everyone in. . . . We need to consider how to best manage that visitation to conserve resources.”

The public simply doesn’t understand the laws governing marine wildlife and how important they are, said Harry Helling, a marine biologist and vice president of the Orange County Marine Institute.

When tide-pooling, Helling said, people often “pick and poke. . . . They take a cool shell. Then at home they find there’s an animal in it.”

Helling also agreed that there are too many visitors.

“It’s frightening to see more and more people pile into a refuge, turning rocks,” he said.

Helling explained that although the state Fish and Game Department responds quickly against poachers, it has a hard time preventing the slow, steady damage people cause.

“Because it’s a gradual impact, it’s hard to detect. . . . It takes a trained eye to notice anything,” he said.

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McDonald developed a keen eye studying the rockweed several hours at a time. In the middle of cold nights during low tide, she was careful not to lose her footing on the slippery, desolate boulders of Monarch Bay.

“What put her in the finals was her depth of knowledge, the dedication and commitment,” said Robyn McGuire, a state fair judge during the Science Student of the Year selection. “She was having fun. One of the things we look for is if they are enjoying it.”

The project adds to knowledge about the environment, McGuire said, and the way McDonald articulated her passion about it won her the top prize.

“I put her on par with something like competing in the Olympics,” Phalen said. “She framed the project as something important to all of us.”

* INSIDE LOOK

What makes a winning science project? Marin McDonald explains. B2