The average golf course slurps up more than 300,000 gallons of water per day, resorts are expensive and exclusive, and, let’s face it — the game is kind of boring. On top of all that, it seems coastal golf courses are contributing to our ocean plastics problem.

California teen Alex Weber discovered tons of golf balls blanketing the ocean floor off the coast of Central California, where she and her father go freediving. So many, they couldn’t see the sand. The balls came from five golf courses — two along the coast, and three more up Carmel River.

“It felt like a shot to the heart,” Weber told NPR. And she wasn’t about to stand idly by. She and her dad, later joined by marine plastics researcher Matt Savoca from Stanford, hauled up more than 50,000 golf balls over the course of two years.

Sometimes, during their collections, they would hear ominous “plinks” from above — more golf balls hitting the water, right where they were diving.

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The overall impact from golf balls on the ocean is probably small (like, say, straws), but they do emit toxic chemicals as they degrade. And, like other plastics, “decomposing” for golf balls really means breaking into tinier bits of plastic, which wind up in the stomachs of marine animals. Don’t hit golf balls into the ocean! And do be more like this teen, now a published author in a scientific journal, who saw something and did something.