Catching Our Breath

If you've ever had the opportunity to visit Dolphin Discovery at the National Aquarium, home to our pod of six Atlantic bottlenose dolphins, you are likely well aware that the portions of the exhibit closest to the dolphin pool are where the excitement is as guests watch Bayley, Beau, Chesapeake, Foster, Jade and Spirit as they cruise, jump, splash and spray.

Some sprays—which can range from a light mist to a powerful burst—are the result of the dolphins' respiratory process. Marine mammals come to the water's surface to take a breath and then can hold that breath for quite a while. Dolphins' lungs, which are far stronger and more elastic than those of land-bound mammals, draw oxygen directly through their blowholes into their lungs—a more direct connection than humans from nose to lung—before releasing it with varying degrees of force depending on their activity level as they return to the water's surface, sending water droplets airborne. As the dolphin then takes its next breath, some of those airborne water droplets are inhaled as the breathing process begins again.

This spray might look like pure fun in Dolphin Discovery, but what can it tell us about how—and what—ocean-dwelling dolphins are inhaling? An ongoing study involving the National Aquarium, the National Oceanic and Atmospheric Administration (NOAA), Johns Hopkins University and the University of New Hampshire is working to better understand how dolphins and other marine mammals are impacted by accidental oil spills.

Using special equipment and the cooperation of some very special subjects (our dolphins), the National Aquarium marine mammal team spent months training the Aquarium pod to take part in this important study, beginning by acclimating the dolphins to the presence of a specialized holographic camera apparatus designed specifically to record the dolphins as they exhaled and inhaled. Once trained to perform specific types of breaths on cue, the dolphins then learned to enter into the camera's physical framework and breathe as the precision camera carefully recorded the process.

Understanding what the dolphins are taking in will help scientists understand how they are impacted by petroleum products suspended in the ocean—specifically at the water's surface—when industrial oil spills occur. Knowing more about how dolphins and other marine mammals fare during oil spills will hopefully lead to a better understanding of how to help them and keep them healthy during environmental emergencies.

Because oil spill events are unpredictable and often occur in remote areas, scientists don't have a full understanding of the makeup and quality of the air at the surface of the water after a spill. The research, which is financed by the Deepwater Horizon oil spill restoration plan, is aimed at gaining a better understanding of the risks posed by compromised water while promoting science that helps marine mammals. A more thorough understanding of how marine mammals are impacted by pollution will help NOAA design restoration plans that help natural populations recover and guide future disaster response. NOAA's account of the full experiment sheds light on what scientists hope to learn and why it matters so much.

National Aquarium Marine Mammal Trainer Kimmy Barron explains that our dolphins were true to their own distinct personalities as they offered their respiratory expertise to the project. "All of our dolphins contributed to the study by breathing next to the camera. However, some of them were extra excited to participate. Foster was our superstar breather, able to do normal breaths, chuffs and exercise breaths reliably on cue. Even though the research is complete, he still gets excited—squeaking and chirping for himself—when we ask him to do the breathing behaviors he learned for the study."

As our team continues to prepare the Aquarium's dolphin pod to transition from the pools of Dolphin Discovery to a more natural ocean water setting, participation in a study like this one is good practice—for our dolphins and their caregiving team—for the kind of work we hope to continue once we establish North America's first dolphin sanctuary.

"We're very excited to have participated in this incredible research project," says Kimmy. "Being able to utilize the training and relationship building we do with our dolphins and apply it to on-the-ground practices that may have a direct impact on the welfare of ocean-dwelling dolphins is humbling and inspiring."