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.
Dmitry 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 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.
Dmitry 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.
The vigorous legal response by the authorities, including the seizure of the ship itself, appears to have caught Greenpeace off guard and left the crew's families and friends worried that the consequences of what the activists considered a peaceful protest could prove much graver than any expected when they set out.
"Naturally, every time Gizem sets out on a protest I feel anxious," Akhan's mother, Tulay, said in written responses delivered through Greenpeace. "I'm a mother, and most of the time she doesn't even tell us she is participating. I've known the risks but couldn't have foreseen that we would come face to face with such injustice."
Critics of the government of President Vladimir V. Putin have added the crew of the Arctic Sunrise to a catalog of prisoners here who have faced politically motivated or disproportionate punishment for challenging the state. Among them are former oil tycoon Mikhail B. Khodorkovsky, the punk performers of Pussy Riot, and the protesters awaiting trial more than a year after violence broke out on the day of Putin's inauguration in 2012.
But there is one crucial difference: Most of those who were aboard the Arctic Sunrise are foreigners.
They hail from 18 nations. Two of them, Denis Sinyakov of Russia and Kieron Bryan of Britain, are freelance journalists who joined the crew to chronicle the ship's voyage, which began in Amsterdam and ended Sept. 19 when Russian border guards borne by helicopters descended on the ship in the Pechora Sea.
Alexandra Harris, 27, of Britain, was on her first trip to the Arctic. Camila Speziale, 21, of Argentina, was on her first trip at sea. Others were veteran Greenpeace activists, including the American captain, Peter Willcox, who was skipper of the Rainbow Warrior in 1985 when French secret service agents bombed it at dockside in Auckland, New Zealand, leading to the drowning of a photographer, Fernando Pereira.
The activists knew the protest was risky. Two of them, Sini Saarela of Finland and Marco Weber of Switzerland, tried to scale the offshore oil platform in the Pechora Sea owned by Russia's state energy giant, Gazprom.
They plunged into the icy waters after guards sprayed water from fire hoses and fired warning shots, and they were plucked from the sea by a Russian coast guard ship and held as "guests." The next day, Sept. 19, however, the Arctic Sunrise was seized by border guards in international waters.
Greenpeace staged a similar but more successful protest in the summer of 2012. In that instance, activists, including Greenpeace's executive director, Kumi Naidoo, scaled the same platform and unfurled a banner. After several hours, they departed, and the Russian authorities did not pursue any charges.
The authorities have shown little sign of leniency since the ship's seizure, despite an international campaign by Greenpeace to draw attention to the prosecutions and even an appeal from Italy's oil giant Eni, a partner of Gazprom, to show clemency for the crew, which includes an Italian, Cristian D'Alessandro.
The prosecution of the Arctic Sunrise crew has punctuated Putin's warnings that he would not tolerate any infringement on Russia's development in the Arctic. The region has become a focus of political and economic strategy for the Kremlin as its natural resources have become more accessible because of the warming climate.
When the government of the Netherlands, where Greenpeace International is based, filed an appeal to the International Tribunal for the Law of the Sea to have the ship and crew released, Russia's Foreign Ministry said it would not recognize the tribunal's jurisdiction, citing the country's sovereignty. The tribunal has scheduled a hearing on the Dutch claim anyway, but unless Russia seeks a compromise that would free the prisoners, the crew could be detained for months awaiting trial.
Greenpeace's activists and their cause have not found much sympathy in Russia, their fate shaped in part by hostile coverage on state-owned or state-controlled television. The main state network, Channel One, recently broadcast an analysis that suggested that Greenpeace's protest had been orchestrated by powerful backers with economic incentives to undermine Gazprom.
After their formal arrest on Sept. 24, the crew members appeared one by one in court and were charged with piracy and ordered held at least until Nov. 24. One by one their appeals for bail were denied. Last week, the regional investigative committee reduced the charges to hooliganism, a crime that nonetheless carries a penalty of up to seven years in prison.
The committee raised the possibility of new charges against some crew members that could result in longer sentences upon conviction.
According to Greenpeace and relatives, the prisoners have not been mistreated in the detention center where they are now held, next to Murmansk's morgue. They have had access to lawyers and diplomats from their respective countries. They are allowed care packages delivered by Greenpeace, occasional phone calls and sporadic visits from those relatives who can make it to Murmansk. The captain and chief engineer were taken to visit and inspect the Arctic Sunrise, now moored in Murmansk's port.
Conditions, though, are grim.
In letters or phone calls to their families, they have described small, unheated cells, unappetizing meals and Russian cellmates who smoke relentlessly. They spend 23 hours a day in their cells, with only an hour of exercise a day in an enclosed courtyard and the periodic visits with lawyers or trips to court for a hearing.
"It's very cold now," Harris, the activist from Britain on her first Greenpeace operation in the Arctic, wrote in a letter to her parents and brother that was widely cited in the British press: "It snowed last night. The blizzard blew my very poorly insulated window open and I had to sleep wearing my hat."
She went on to express a measure of resolve, saying she practiced yoga in her cell and tapped on the wall to the music piped in, but she also wrote of uncertainty in a confinement that she compared to slowly dying.
"I heard that from December Murmansk is dark for six weeks," she wrote. "God, I hope I'm out by then."
By STEVEN LEE MYERS
The New York Times