An hour into the Marine Research and Education, Inc. program, Oscar Genera delicately sampled the red plankton floating in the palm of his hand.

“I ate all mine, but I’m not filled up,” the Lake Tahoe Environmental Science Magnet School second-grader said. “They tasted yummy.”

In addition to observing — and, in Genera’s case, sampling — Tahoe’s living organisms, the students on the Wednesday cruise learned how to test water clarity with a Secchi disk, determine pH and measure dissolved oxygen content.

“It’s all about educating the kids. It’s important,” Program Manager Harold Singer said. “I don’t think many of them have been on a boat before.”

South Shore residents Dean Lockwood and John Shearer founded the Marine Research and Education Inc. nonprofit in 1999 to promote environmental awareness and conservation of the basin. Shearer operates Tahoe Sport Fishing and the 45-foot U.S. Coast Guard Certified boat, the Prophet, which serves as both a fishing charter and the research vessel for local students. One second-grader demanded to know if the crew worked as fishermen or scientists.

More than 13,500 South Shore students have passed through the marine research program since its inception 13 years ago. Typically every elementary school class gets the chance to participate on one of the trips, which run in the fall and the spring, according to Singer.

In addition to the on-the-water segment, the students learn about the Tahoe watershed and the impacts of pollution during an on-shore classroom session.

The children boarded the Prophet Wednesday morning at Ski Run Marina before motoring to a 335-foot-deep spot just off the Tahoe Keys, where they took water samples and measured the lake’s clarity by dropping the white Secchi disk into the water.

“It helps the kids visualize … If they’re second-graders, we just want them to understand the basics,” Marine Research and Education Teacher Kathy Percival said Wednesday.

The program, which costs about $450 per class, is funded by the Lake Tahoe Education Foundation, the El Dorado Community Fund and the Vail Resorts Giving Council. It’s closely aligned with schools’ curriculum and is designed to achieve grade-specific science standards for California and Nevada, Singer said.

Second-grader Mattison Broadfoot grinned as she peered out over the foamy wake. She’d been on a motor boat “bunches of times,” but the science-component was new.

“We’re just riding a boat and looking for fishes today,” she said.