Penn was in the middle of the North Pacific Gyre, an area that has become notorious for its plastic problem. A large circulating current, it causes plastic pollution to accumulate, breaking down under UV rays until they become tiny fragments called microplastics. Some fragments stay on the surface, while others sink. As microplastics, some enter the food chain -- and, eventually, human bodies.
The experience spurred Penn on to a career in ocean conservancy, and she's been following the plastic ever since.
In 2014 Penn co-founded eXXpedition, a series of all-women sailing voyages. Age 27, she wanted to boost female participation in sailing and science careers, through expeditions that would highlight the abundance of plastic and toxic chemicals, study its distribution in the world's waters, and address possible impacts on human health.
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The latest and most ambitious voyage, eXXpedition Round the World, is a multi-year venture and will eventually travel to four of the planet's five giant ocean gyres in the North and South Atlantic, the South Pacific and the Indian Ocean. The crew comprises 300 women from over 30 nations, working in groups of 10 across 31 legs.
The idea came to her when investigating persistent organic pollutants (POPs), "highly toxic" chemicals that can last for several years before breaking down, according to the United Nations, and which research suggests can accumulate on plastic in water. Human exposure to POPs comes from a variety of sources, but mainly through food according to the World Health Organization. POPs work their way up food chains in a process called biomagnification, increasing in concentration the higher up the food chain they go.
A test for 35 POPs revealed 29 were present in Penn's body. "Being a woman, having those chemicals inside my body during pregnancy would be really bad news," she says. "I thought, 'Wow, this issue is actually quite a female-centered issue. Why not tackle it with an amazing team of women?'"
The team is focusing on microplastics, sampling for airborne particles, trawling the surface and scooping plastic from depths up to 25 meters (82 feet). Some samples are then tested for POPs.
One recent study estimated there could be between 12.5 and 125 trillion plastic particles floating in the oceans. "It really breaks our hearts when we pull that trawl over every time and find fragment after fragment of plastic," says Penn, who points out many more plastic particles will have sunk.
In March, Covid-19 stalled the eXXpedition's progress across the South Pacific. The mission was put on a 12-month pause, eight legs into its 38,000-nautical mile journey. The vessel remains moored in Tahiti while its international crew has returned home. In the meantime, the eXXpedition's advocacy work has moved online -- a fitting forum for a global problem.
"Our ocean doesn't know political borders or cultural boundaries," Penn says. "Th
