BUXTON — On yet another hot summer Sunday afternoon, large groups of interconnected tubes and inflatable swans and unicorns floated down the Saco River, creating a constant parade of plastic party barges. And many a reclining reveler carried a beer-cozy-wrapped beverage.

How many of those beer cans and bottles ended up in the river?

A group of divers and snorkelers who hail from Aroostook County and now live in southern Maine came to find out. Consider them Team Caribou, or the Scuba-and-Snorkel Samaritans.

The group of friends have made it their personal mission this summer to help clean up the Saco River. Three of them were certified in scuba diving in the past year.

“Who’d have thought the potato pickers would become divers?” said Sarae Sager, a medical student at the University of New England and the only female member of the group.

Since July 17, after a weekend of debauchery at Pleasant Point Park forced Buxton police to close the wooded park that flanks the river, the band of Caribou friends have come to the river at least a dozen times to dive and snorkel in search of trash. They always haul up at least a few bags full of bottles and cans. said 26-year-old Liam Bergin of Portland.

“If more people took out more than they throw in, they wouldn’t have to close the park,” Bergin said.

The weekend the park closed, 336 empty beer cans and bottles, 92 soda cans and 15 rubber floats were removed from the 60-acre park, according to Buxton police. Yellow police tape went up at the park’s three entrances and metal no-trespassing signs were posted.

But people still float along the river past the park and, according to Bergin, still dump in the river.

Pleasant Point is not the only park in Maine that closed because of derelict behavior this summer.

Recently, Mahoosuc Land Trust closed Step Falls Preserve in Newry until Sept. 7. It was chiefly an issue of “increasing and unacceptable overcrowding,” according to the land trust, but the result was dangerous behavior.

The weekend of July 25-26, cars overflowed the lot and parked illegally on busy Route 26 and the lawns of local residents, the land trust reported.

Closer to Buxton, The Nature Conservancy closed the Saco Heath at the onset of the pandemic in Maine for similar reasons.

For Buxton police, Pleasant Point Park remains a battleground. Young people continue to go to the park, despite several prominent “no trespassing” signs. In the days after the park closed, Buxton police said 40 people were cited for criminal trespassing.

Sager and George Belanger, both 27, and Lance Jandreau and Bergin, both 26, played sports together at Caribou High. When they all ended up in southern Maine – the three men for work and Sager for college – they continued to hang out and go camping together.

Bergin, a Florida native, always loved to snorkel. But two of the friends followed Jandreau’s lead into scuba classes to get certified in diving. His father, Robert Jandreau, a former diver in the U.S. Marine Corps, was his inspiration.

Cleaning up trash in lakes and rivers, Jandreau said, is simply a part of the diving ethic that’s taught in certification classes. But Sager said growing up in Aroostook County, where the forested landscape is wild and pristine and clean watersheds are rich with native, wild fish, picking up trash is an automatic response for all four in the group.

They went to the Saco River in mid-July to have fun diving. But when they heard about the reasons Pleasant Point Park closed, Sager said, they doubled down on their effort to find trash there.

“It’s just another way to explore Maine and our home,” Sager said. “I think it’s a privilege to be able to give back to our community and nature by cleaning it up. We didn’t know at first it was a need that was going unfilled. We were doing it last year. But now we’re doing it more.”

The diving team often sees people floating down the river tossing cans in the river, Jandreau said. They find antique beer cans clearly left years ago, and even unopened bottles discarded more recently.

“It’s just so easy to litter. So easy,” Jandreau said. “Leave it better than you found it. That’s the diver ethic.”

On Aug. 9, just as some of the last party floats on the Saco passed the park, a small motorboat weighed down with snorkelers and divers went the other way. A red-and-white dive flag – the international sign to alert boaters of a scuba diver underwater – hung from the back.

The boat slowly made its way to a spot on Pleasant Point Park beside the river known, appropriately, as “Party Rock,” where young revelers frequently gather on the cliffs above. Here the divers jumped into the shallow water to don their gear, while visiting friends from The County – including Jandreau’s younger brother, Cory – hopped out to snorkel.

Sager, Bergin, and Lance Jandreau slung scuba tanks on their backs, while Belanger prepared to snorkel near them.

“When we run out of (oxygen in our tanks), we snorkel, too,” Sager said with a grin.

The group swam over to a deep area next to the cliffs. Later they would move into the river channel. The diver flag attached to a buoy alerted the drivers of pontoon boats, motorboats and jet skis of the divers below.

“The reaction we get from most people is surprise,” Bergin said. “Anyone sees us with our gear on, they ask what we’re looking for. When we say we’re cleaning up trash – we always get a surprised reaction. Nobody’s ever heard of someone doing that before. What surprises me is how surprised they are.”

The fun part of their trash detail, Bergin said, is the “cool stuff” they find and return to people.

Three weeks ago, while Bergin and Belanger snorkeled together along a mile stretch of the river up to Pleasant Point Park, Bergin helped a man find the fishing rod he dropped in the river a week earlier – with the $200 reel intact. Bergin and Belanger have returned two wallets to people.

They often find cellphones or Apple watches – although those are harder to open to find contact information. Two weeks ago, Lance Jandreau found a bike on the bottom of the river (but it was too embedded in the river bottom to pull out).

Aug. 9 was their biggest haul yet, but Jandreau suspects there’s more in the river they never see.

“A lot of it is buried by silt and sand. You have to look for it,” he said.

Many of those floating down the river that day knew about the park’s closure – and the trash problem.

Barbara Gagnon came from Millinocket to float the river for the first time with friends from Biddeford and Sanford. Gagnon said she’d heard of the popular river trip for years and always wanted to do it. After an hour-and-a-half float, the three women proudly showed off a dozen returnables they picked out of the river in a dry bag.

Ludmila Svoboda of Limerick said she and her 8-year-old son watched as a large group floated past them and dropped cans in the river. Svoboda used it as a teaching moment for her son, Abner Deans.

“It’s unfortunate. It’s not uncommon to see it with large groups,” Svoboda said. “I told my son we have to respect the river to take care of the water and wildlife. We’ve been coming to the river for 10 years. We’re so lucky to live in Maine and to have this clean river. Kids need to know that behavior is not OK.”