For four weeks this summer, rising juniors Josh Friedman and Schuyler Nardelli sailed from Honolulu, Hawaii, to Sausalito, Calif. Aboard a 134-foot vessel with 17 other students and 12 crew members, they conducted research on the effects of ocean acidification on tiny pelagic snails and used celestial navigation to chart their ship’s course.

The two students were part of a study program run by Sea Education Association in Woods Hole, Mass. The SEA program is divided into two sections: one on land and the other on sea. Undergraduates first study oceanography, marine studies and nautical science, before taking off for a four-week, 3,000-mile sea trip.

Besides conducting self-designed research on the pteropod Limacina, research that culminated in a 51-page paper, Friedman and Nardelli learned how to sail a big boat without relying on GPS devices or radars. “We used a sextant to shoot the sun and the stars, and after doing reductions we were able to plot our position on a chart to find out where we were — the old way,” Friedman said.

For Nardelli, this was also her first experience being on the ocean. “I’ve always been a science person and into the environment, but the ocean was new and different for me,” she said. “It is so vast and mysterious, and it was cool to figure out some of the components that make it so mysterious.”

Both Friedman and Nardelli are majoring in earth and oceanographic studies and environmental studies. Nardelli said she chose her major after taking an introductory oceanography class last spring with Associate Professor of Earth and Oceanographic Science Collin Roesler, who also encouraged her to enroll in SEA’s research program. “I absolutely loved [Roesler’s course] and decided I wanted to explore the ocean more,” Nardelli said.

The two Bowdoin students ended up in a small research team, along with a third student in the program. The three collected pteropods at night, when the organisms rise to the ocean surface to feed. Using a microscope to observe the creatures, which can be the size of a pencil point, Friedman said his team discovered a correlation between shell degradation and decreasing pH levels of the ocean. Ocean acidification is the result of rising CO2 emissions. They also noticed a shift in zooplankton communities toward more gelatinous rather than calciferous (hard-shelled) organisms, such as the pteropod. “As the chemical factors change, causing a decrease in calciferous organisms, gelatinous organisms might fill that niche,” he said.

Nardelli said their research, and that of other scientists studying ocean acidification, augurs a poor outcome for marine life. “We found that a lowering of the pH in the water was indeed causing their shells to degrade, which is a sad future for the pteropod and zooplankton in general — and for the food chain, because zooplankton is at the low end of the food chain,” she said.

Nardelli and Friedman will receive three academic credits for their time at SEA. They also acquired another reason to focus their futures on the ocean. “There were some times I would be on deck and…see stars stretching from horizon to horizon and the sun rising,” Nardelli said. “And I’d see a bigger picture of the world and how insignificant the problems on land were.”

Friedman, who is from Santa Monica, said he grew up diving with his parents. He is also an avid underwater photographer. “The ocean is a spectacular place I always want to be,” he said.