MOSCOW — Gizem Akhan, 24, was about to begin her final year studying the culinary arts at Yeditepe University in Istanbul. Tomasz Dziemianczuk, 36, took a vacation from his job as a cultural adviser at the University of Gdansk in Poland that has now unexpectedly turned into an unpaid leave of absence.

Dmitri Litvinov, 51, is a veteran activist who as a child spent four years in Siberian exile after his father, Pavel, took part in the Red Square protest against the Soviet invasion of Czechoslovakia in 1968.

“I didn’t expect my son to get in their clutch,” the elder Mr. Litvinov said in a telephone interview from Irvington, N.Y., where he settled to teach physics in nearby Tarrytown after being expelled from the Soviet Union in 1974.

Dmitri Litvinov and the others are just three of the 30 people aboard a Greenpeace International ship, the Arctic Sunrise, who are now confined in separate cells in the far northern city of Murmansk after staging a high-seas protest last month against oil exploration in the Arctic. All face criminal charges that could result in years in prison as a result of having grossly underestimated Russia’s readiness to assert — and even expand — its sovereignty in a region potentially rich with natural resources.