Opened empty travel bag on the bed.

Many researchers’ suitcases have remained empty now for more than a year.Credit: Shutterstock

In ‘normal’ times, Mike McCulloch has to scour the globe to find a person able and willing to join his laboratory. “My science is quite controversial, so I don’t get many applications for posts,” he says.

But these are not normal times. The COVID-19 pandemic has severely disrupted the mobility of scientists, as evidenced by McCulloch’s recent job advertisement, posted in April on Twitter. Usually, McCulloch needs to look high and low for people able and willing to help him with his controversial work at the University of Plymouth, UK. His aim is to harness relativity to pull rockets through space without the need for backwards thrust — an approach with its fair share of detractors. But pandemic-related border restrictions meant that he needed to limit his search to the United Kingdom. Those restrictions have now eased a little, but McCulloch is unsure about what that means for his search. “It’s quite important for me to have a wide range of countries to recruit from,” he says.

His last search for a postdoc turned up a single qualified and available researcher, who was from Spain. “I’ll try to fill the post one way or another,” he says. The United Kingdom’s departure from the European Union is widely expected to complicate research mobility, particularly if junior scientists in Europe foresee bureaucratic tangles associated with having to move, but McCulloch thinks pandemic-related restrictions will be a bigger problem.

More than a year after the first lockdowns and border closings, scientists around the world are still grappling with the pandemic’s impacts on mobility. Researchers are navigating a world where the rules — and the challenges — are seemingly in constant flux. Whether they are stuck far from home, separated from team members or forced to rethink their approach to recruitment, they’re trying to keep their science moving forwards (see ‘Push on through’).

Uncertain future

Most scientists managed to stay productive in the first year of the pandemic, but the relative lack of mobility for the global scientific enterprise will have long-lasting impacts that could transform research and collaboration, warns Giorgio Marinoni. Marinoni is the manager of higher education and internationalization at the International Association of Universities (IAU), a non-governmental organization based in Paris that promotes global cooperation in higher education. He worries that disruptions in travel could stifle the careers of junior scientists. “For a young researcher, mobility is part of the career,” he says. “We might be heading for a future where there isn’t such a global research community.”

The pandemic threatens to undo much progress towards scientific globalization, agrees IAU secretary-general Hilligje van’t Land. Researchers from economically disadvantaged countries will bear most of the brunt, she says. “There’s no way for them to travel, and they may not have a vaccine for a while depending on where they are from.” And that will not only limit their own opportunities, it will also deprive the system of their

Vast watery parcels of plastic – made of soda bottle flotsam and shopping bag jetsam – appear in our oceans as large floating islands. On roadways, plastic is often tossed, broken down into smaller pieces and churned until it is microscopic, at which point it is swept into the atmosphere and travels the world.

By sea or by land, these tiny shards of plastic are more ubiquitous than science had known, according to a new study led by researchers at Cornell and Utah State University. The research was published April 12 in the Proceedings of the National Academy of Science.

A blue microplastic shard sits among dust and fibers on a filter under a microscope.

Natalie Mahowald, Cornell’s Irving Porter Church Professor in Engineering, and lead author Janice Brahney, Utah State University assistant professor of natural resources, have found that plastics cycle through the oceans and roadways and, if tiny enough, can become microplastic aerosols, which ride the jet stream across continents.

“We found a lot of legacy plastic pollution everywhere we looked; it travels in the atmosphere and it deposits all over the world,” Brahney said. “This plastic is not new from this year. It’s from what we’ve already dumped into the environment over several decades.”

Results from their study, “Constraining the Atmospheric Limb of the Plastic Cycle,” suggest that atmospheric microplastics in the western United States are primarily derived from secondary re-emission sources.

From December 2017 to January 2019, researchers collected atmospheric microplastic data from the western U.S., where 84% of microscopic shards came from road dust – cars and trucks agitating the plastic. About 11% entered the atmosphere from sea spray, and 5% was derived from agricultural soil dust.

As large clusters of refuse plastic merge into pods of plastic islands on the oceans, the oceanic action grinds them into mere micron-size particles, where the winds ferry them into the atmosphere – for as little as an hour, or as long as six days.

In the process of conducting other scientific research, Brahney had discovered bits of microplastic everywhere she went. Marje Prank, a postdoctoral fellow who  worked with Mahowald, developed a microplastic transport model to determine the tiny plastics’ origins. Together, they used the model to deduce the sources of these microplastics.

“We did the modeling to find out the sources, not knowing what the sources might be,” said Mahowald, a fellow at the Cornell Atkinson Center for Sustainability. “It’s amazing that this much plastic is in the atmosphere at that level, and unfortunately accumulating in the oceans and on land and just recirculating and moving everywhere, including remote places.

“Using our best estimate of plastic sources and modeled transport pathways, most continents are net importers of microplastics from the marine environment,” she said. “This underscores the cumulative role of legacy pollution in the atmospheric burden of plastic.”

Microplastics are landing and accumulating in all sorts of places, Mahowald said. “It’s not just in the cities or the oceans,” she said. “