WAIMANALO — Natalie Cross of Manoa was driving to Kailua when she spotted the yellow roadway sign at the entrance to Bellows Air Force Station announcing yesterday's beach cleanup.

"I thought, 'Why not?' " Cross said while combing the white-sand stretch of beach at 4 p.m. yesterday for marine debris with about 100 other volunteers. "I've been wanting to get involved in beach cleanups."

Cross, 42, who teaches English at the University of Hawai'i-Manoa, planned to spend the afternoon relaxing at a beach in Kailua but thought her time was better spent at Bellows.

"I feel like I'm doing something constructive," she said after picking up a toothbrush and pulling a blue multifilament net line from the sand.

The East O'ahu Lifeguard Association, which is not affiliated with the city although its membership includes city lifeguards from East Honolulu and Windward O'ahu, organized yesterday's cleanup with the help of Hawai'i Kai residents Suzanne Frazer and Dean Otsuki.

Bellows was the third cleanup since April organized by Frazer, a Queensland, Australia, native who is studying dance at UH. She previously set up cleanups April 1 at Waimanalo Bay Recreation Area and April 29 at Waimanalo Beach Park.

"The thing about marine debris," Frazer said, "is it's not anybody's responsibility but it needs to be everybody's responsibility. People have the idea that it's the city, state or military's job to clean the beach. We need more people to be aware that they can do their bit.

"Where I grew up, we took responsibility to keep the beaches clean because like Hawai'i, they are a selling point in Queensland."

The April 29 beach park cleanup alone produced 80 bags of trash, two truckloads of netting and, more specifically, 9,000 pieces of plastic, 369 pieces of net twine and 163 Styrofoam items in addition to rubber, metal, glass and wood, according to Frazer.

"We went back the following week and filled 20 more bags of trash," Frazer said.

Yesterday's Bellows cleanup produced 98 bags of trash, according to Frazer. Volunteers found nine tires, a large wire cage and stacked more than 30 piles of driftwood, which will be removed today by Boy Scouts.

Marine debris in Hawai'i is affected by North Pacific, California, North Equatorial and Kurishio ocean currents and atmospheric winds. "We find black tubes from oyster traps in Japan," Frazer said.

Another source of debris are local streams and drainage canals, she said.

"And we have people who come to the beaches and leave their trash or shove paper wrappers into the rocks," Frazer said. Others use the beach for an ashtray.

Five Girl Scouts from Troop 377 — Carrie Glenn, 11; Lahela Naki, Catherine Coleman and Elianna deVre, all 10; and Jennie Yamada, 9 — and three junior scouts from Troop 702 — Gracie, 4, and Anna Zucchero, 6; and Elizabeth Coleman, 6 — came from Manoa to help with the cleanup yesterday.

"We want to keep our environment safe for fishes and other sea life," Lahela Naki said. "We don't want it to pile up."

Rap Craig of Kalama Valley, a Hawai'i Pacific University facilities manager and Coast Guard reservist whose duty this past weekend was lighthouse keeper at Makapu'u Lighthouse, brought his daughter, Ishay, 13, and son Kainoa, 6, to yesterday's cleanup.

While concerned with marine debris, Craig's big peeve is the trash some people thoughtlessly leave behind. Bellows is open to the public on weekends.

"I've been coming to this beach for 20 years and in the last two years, the rubbish has gotten out of control," Craig said. "Maybe they need to provide more garbage cans but I think it's mostly people just being lazy. We've found everything from aluminum beach chairs to body boards."

Ishay Craig added: "It's not hard to keep the beach clean. You just have to want to do it."

Reach Rod Ohira at rohira@honoluluadvertiser.com.