A plastic microfiber found in the exhaled breath of a bottlenose dolphin is nearly 14 times smaller than a strand of hair and can be seen only with a microscope. Credit: Miranda Dziobak/College of Charleston,

Bottlenose dolphins in Sarasota Bay in Florida and Barataria Bay in Louisiana are exhaling microplastic fibers, according to our .

Tiny plastic pieces have spread all over the planet鈥, and even . An are estimated to be in the oceans alone. Across the globe, research has found and are exposed to microplastics mainly through , but also through .

Our study found the exhaled by bottlenose dolphins (Tursiops truncatus) are similar in chemical composition to those . Whether dolphins are exposed to more of these pollutants than people are is not yet known.

Why it matters

In humans, inhaled microplastics can cause , which can lead to problems including . Since dolphins and humans inhale similar plastic particles, dolphins may be at risk for the same lung problems.

Research also shows plastics contain chemicals that, in humans, can affect , and . Since , microplastics may well pose these for them, too.

As , bottlenose dolphins help scientists understand the impacts of pollutants on 鈥攁nd the related health risks for people living near coasts. This research is important because lives within 62 miles (100 km) of a coast.

What still isn't known

The ocean releases microplastics into the air through surface froth and wave action. Once the particles are released, wind can transport them to other locations. Credit: ,

Scientists estimate the , which get there through runoff, wastewater or settling from the air. Ocean waves can .

In fact, bubble bursts caused by wave energy can release 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 . 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 , too.

Our research found microplastics in the breath of dolphins living in both urban and rural , but we don't yet know whether there are major differences in amounts or types of between the two habitats.

How we do our work

Breath samples for our study were collected from wild during catch-and-release health assessments conducted in partnership with the , , and .

During these brief permitted health assessments, we held a petri dish or a customized 鈥攁 device that measures lung function鈥攁bove the dolphin's blowhole to collect samples of the animals' exhaled breath. Using a microscope in , 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, used a specialized method called , 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鈥攁nd 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.

Journal information: PLoS ONE

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