In fact, bubble bursts caused by wave energy can release 100,000 metric tons of microplastics into the atmosphere each year. Since dolphins and other marine mammals breathe at the water’s surface, they may be especially vulnerable to exposure.
Where there are more people, there is usually more plastic. But for the tiny plastic particles floating in the air, this connection isn’t always true. Airborne microplastics are not limited to heavily populated areas; they pollute undeveloped regions too.
Our research found microplastics in the breath of dolphins living in both urban and rural estuaries, but we don’t know whether there are major differences in amounts or types of plastic particles between the two habitats.
How We Do Our Work
Breath samples for our study were collected from wild bottlenose dolphins during catch-and-release health assessments conducted in partnership with the Brookfield Zoo Chicago, Sarasota Dolphin Research Program, National Marine Mammal Foundation, and Fundación Oceanogràfic.
During these brief permitted health assessments, we held a petri dish or a customized spirometer—a device that measures lung function—above the dolphin’s blowhole to collect samples of the animals’ exhaled breath. Using a microscope in our colleague’s lab, we checked for tiny particles that looked like plastic, such as pieces with smooth surfaces, bright colors or a fibrous shape.
Since plastic melts when heated, we used a soldering needle to test whether these suspected pieces were plastic. To confirm they were indeed plastic, our colleague used a specialized method called Raman spectroscopy, which uses a laser to create a structural fingerprint that can be matched to a specific chemical.
Our study highlights how extensive plastic pollution is—and how other living things, including dolphins, are exposed. While the impacts of plastic inhalation on dolphins’ lungs are not yet known, people can help address the microplastic pollution problem by reducing plastic use and working to prevent more plastic from polluting the oceans.