(CNN) Russian scientists are finding themselves isolated as Russia's invasion of Ukraine enters its second month.
The country's Mars rover project with the European Space Agency is on hold. Russian institutions have been suspended from CERN, the world's largest particle physics lab, in Switzerland. A prestigious math conference has been moved from St. Petersburg to a virtual meeting, and Russian scientific journals are being frozen out of key international databases.
High-profile scientific journals such as Science and Nature aren't rejecting research submitted by Russian scientists, but financial sanctions placed on Russia may make paying journal processing fees tricky. Ukrainian researchers are calling for a complete boycott of Russian institutions and academics.
But while welcoming the outpouring of support across the West for Ukrainian scientists, some academics think that shunning all Russian scientists could be counterproductive.
"Shutting down all interaction with Russian scientists would be a serious setback to a variety of Western and global interests and values, which include making rapid progress on global challenges related to science and technology, maintaining non-ideological lines of communication across national boundaries, and opposing ideological stereotyping and indiscriminate persecution," said a letter published Thursday in the journal Science authored by five prominent scientists from the United States, Canada and the United Kingdom.
John Holdren, a research professor in environmental science and policy at Harvard Kennedy School and the science adviser to former US President Barack Obama, was one of the authors. He said he wanted to make sure there was balance in the measures taken to punish Russian President Vladimir Putin and his regime.
"I put a very high value on cooperation in science and technology, " Holdren said. "My colleagues and I who wrote that letter together were alarmed by reports that what was underway was a wholesale demonization and isolation of Russian scientists."
Germany has taken one of the swiftest and strongest stances. On February 25, the Alliance of Science Organisations in Germany recommended that all academic cooperation with state institutions and business enterprises in Russia be frozen with immediate effect and German research funds no longer benefit Russia.
A German-built space telescope making the largest map of black holes in the universe has been switched off. The black hole-hunting telescope, called eROSITA, short for extended ROentgen Survey with an Imaging Telescope Array, launched in 2019 from the Baikonur Cosmodrome in Kazakhstan aboard the Spectrum-Roentgen-Gamma satellite, a joint Russian-German science mission supported by Roscosmos, the Russian space agency.
The DFG or German Research Foundation, which had funded more than 300 German-Russian research projects with a total volume of over 110 million euros over the past three years, suspended all its research projects with Russia.
Scientific publisher Clarivate said earlier in March it had has ceased all commercial activity in Russia, closing its office there. Its influential Web of Science publication database won't include new journals based in Russia or Belarus, which has supported the Russian invasion. The database tracks citations -- a key yardstick of scientific success -- that helps scientists get noticed.
In the United States, MIT has ended the relationship it had with the Skolkovo Institute of Science and Technology (Skoltech) in Moscow, although it stressed that it was proud of the research the collaboration had produced over the past decade.
"This step is a rejection of the actions of the Russian government in Ukraine. We take it with deep regret because of our great respect for the Russian people and our profound appreciation for the contributions of the many extraordinary Russian colleagues we have worked with."
Nature, a leading UK publisher of scientific journals, said that calls for a comprehensive and worldwide boycott of all Russian research, and for scientific journals to refuse to consider papers by researchers from Russia were "understandable." But it said that it will continue to consider manuscripts from all over the world.
"That is because we think at this time that such a boycott would do more harm than good. It would divide the global research community and restrict the exchange of scholarly knowledge -- both of which have the potential to damage the health and well-being of humanity and the planet."
NASA has said it's still working closely with the Russian space agency on the International Space Station despite the mounting political tensions. On Wednesday, NASA astronaut Mark Vande Hei is set to return to Earth alongside Russian cosmonauts Anton Shkaplerov and Pyotr Dubrov.
Science has long been a cross-border endeavor, and many Russian scientists have close ties with their counterparts in the United States and Europe.
Mikhail Gelfand, a Russian professor who studies comparative genomics and molecular evolution, is one of them. Gelfand said that so far his day-to-day work has not been affected, but he said that he expected some of his experiments to be stalled because international sanctions would make it hard to get hold of some lab supplies.
He also said he was spending a lot more time writing letters of recommendation for colleagues and students trying to leave Russia.
A complete boycott of Russian scientists and institutions would be unfair, he said. "Unlike other actions, this will not influence the war; this will help the oppressive regime to get tighter hold on what is still alive in Russia; and it will punish mainly the people who oppose the war," Gelfand said.
Gelfand helped organize a letter against the war that he said was signed by more than 8,000 Russian scientists. It has since been blocked online by Russian authorities, he said.
In the letter to Science, Holdren and his colleagues said that while government-to-government collaboration was "understandably on hold," they stressed that "not all engagement with Russian scientists should be." Climate change and the Arctic were two areas were Russian scientific efforts were particularly important, Holdren said.
They also noted that many thousands of Russian academics and students "live and work in the West," according to the letter, and many have been critical of the Russian government.
"Surely these Russians should not be lumped together with leaders of the Russian state. Rather, humanitarian provision should be made to ensure that, as their visas and passports expire, they are not forcibly repatriated to face not only isolation from their Western colleagues but also, very possibly, persecution," they wrote.
"Decisions made in Western countries today about how to deal with Russia and Russians may be in place for a long time and, ultimately, difficult to reverse. We fervently hope that all future decisions about Russian scientists and Russian academic institutions will reflect a balanced appraisal."