If you want to get a picture of wild dolphin populations' health, it's typically necessary to capture some of the animals and then obtain blood samples or skin biopsies. Needless to say, it's hard work, and the dolphins tend not to like it. Soon, however, it may be possible to gather the same information using a device that samples their breath.

There are already systems that can detect diseases or other disorders by analyzing the mix of metabolites in a human patient's exhalations. Metabolites are small molecules from a variety of compounds, which are associated with metabolic functions. They can also be used to get a sense of someone's activity level, diet, or exposure to environmental elements.

Prof. Cristina Davis – a scientist at the University of California in Davis – had worked on such devices previously, and wanted to adapt the technology for use on dolphins. Given that the creatures are able to exchange up to 90 percent of their lung capacity in less than one second, she figured that their breath should be pretty data-rich.

Working with colleagues from UC Davis, the National Marine Mammal Foundation in San Diego and the Chicago Zoological Society's Mote Marine Laboratory, she developed an insulated tube-style device that is held over a dolphin's blowhole. When the creature exhales, the air goes into the tube and is frozen for subsequent analysis.

The breath-sampling tool in use (Photo: American Chemical Society)

The device was tested on wild bottlenose dolphins and captive animals. In both cases the dolphins still had to be captured and temporarily restrained, although we're told that future versions may allow for breath-sampling while the animals are free and swimming.

Back in the lab, the researchers "were able to identify changes in the breath of animals affected by disease or other factors" by comparing individual dolphins' readings to baseline profiles of animals that were known to be healthy. It is now hoped that once perfected, the device could be used not just to assess the health of dolphins, but by extension the marine ecosystem as a whole.

A paper on the research was recently published in the journal Analytical Chemistry.

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