Drones have a whale of a time!
In the past many species of whales were hunted for their oil to the point of extinction; thanks to international treaties observed by many countries whale numbers have since begun to recover. But we still know relatively little about them, and it’s hard to conserve something that you understand only poorly. At the same time, you don’t want to distress or disturb an animal in an attempt to study it.
So, researchers at Murdoch University, in Perth, Western Australia, have set up a programme to monitor whales using drones; these are used to capture samples of exhaled air that can be analysed to produce a chemical snapshot of the animal’s biochemistry - this is called its “phenome”. Chris Smith spoke to Murdoch University's Garth Maker...
Garth - The phenome is effectively the entire biochemistry of an organism as reflected by the interaction between their genes and the environment. In many respects, it’s the closest representation of the final physiological state of an individual – say, a human or another organism. And so, it’s reflective of everything that is potentially coded within the genes and then all of the other influences that then lead to that final state of the organism.
Chris - What sorts of things do you measure? What sorts of samples do you have to collect to do that?
Garth -So the key focus is on urine samples and blood samples, but there are other sample types that can also be analysed. In these analyses, we’re looking for all the small molecules – so the carbohydrates like the sugars, fats, proteins, amino acids specifically as well, and then a lot of other smaller molecules, and of course, anything that maybe not normally found within the organism; so maybe drug molecules or molecules that are present from food or environmental exposures as well.
Chris - So rather than looking for just one chemical, what you're saying is you look at a whole spectrum of different chemicals and you're looking at the levels of each of them relative to each other. It’s like a chemical fingerprint that you can then say, “Well, we know this person has disease or condition X, and when we see that condition, we see this sort of chemical fingerprint.”
Garth - That’s exactly right and it’s really taking the old-fashioned clinical biochemistry which would maybe measure a single molecule or a couple of molecules and saying, “Well, let’s measure as much as we can many thousands of these molecules in a single analysis and see how that entire fingerprint changes with – as you say, with diseases or maybe with specific exposures to treatments or other chemicals as well.”
Chris - What sorts of gadgetry or expensive equipment do you need to make those measurements?
Garth - So this is primarily achieved through a combination of two technologies – liquid chromatography which separates the molecules on the basis of their chemistry and then mass spectrometry which actually analyses the molecules and gives us a measurement of their specific mass that allows us to identify them and figure out what they are.
Chris - You can do this fast enough to actually make this a practical diagnostic tool.
Garth - The goal of the phenomics concept is to actually take these analyses which have typically been undertaken in a relatively slow fashion and now, make them higher throughput so that we can do them in a setting that is relevant to clinical diagnosis.
Chris - Just human medicine or are there other things you could do with it?
Garth - Absolutely, it can be applied to any biological system. The driver has certainly been medicine, but there are many other applications including agricultural settings and also in wildlife biology as well.
Chris - Like what?
Garth - So, an investigation we’re undertaking at the moment is to look at the breath that is exhaled by whales and dolphins.
Chris - Breath of a blowhole?!
Garth - Okay! So the "blow" that is provided by these animals! Breath analysis has been undertaken in humans. For some time, it is actually growing in popularity as a means of diagnosis because it’s really easy to collect. And so, that thinking has now led to a few studies which have started to look at whether we can do this in the large aquatic mammals. It’s very difficult to sample from these organisms. It’s difficult to get close to them safely. Many of them are threatened or endangered species, so we don’t wish to interfere with them in their natural environment. So ideally, we’d like a way to sample from these organism that is non-invasive, and one of the ways that we can potentially do that is to sample the blow that is exhaled by them as they surface.
Chris - This sounds very impractical. What are you going to do? Chase a whale down and every time it breaths out, you just try and catch some of the breath.
Garth - That’s a very good question. With things like dolphins which are often found closest to the shore, there are dolphin populations around Perth that are used to interacting with humans. So we can do that using basically a pole with a collection device at the end. For whales, the approach is actually to use drones. So the drones fly over the whales as they are approaching the surface and then hover over the animal. Once it then blows out its breath, that can then be sampled and then brought back to researchers on a boat.
Chris - What chemicals are in the breath that you can look at then?
Garth - Hormones – so things like cortisol which can be used to examine the stress levels of the animals, and at the same time, some of the hormones associated with pregnancy; things like progesterone may be able to determine the pregnancy status of the animal without having to conduct more invasive measurements.
Chris - And there's enough of those things in trace amounts in the breath for you to see that.
Garth - It’s very much a work in progress, but it seems from the literature, there are studies that have been undertaken so far that these analyses are actually practical from breath analysis.
Chris - You, presumably, are not just starting to try it out in the ocean with a team of drones. How are you sort of scaling this? How are you doing the preliminary studies?
Garth - So we’re undertaking some lab-based simulations at the moment to make sure that the technology is up to the task. Then we’ll move on to dolphins. They're more easily interacted with and they're used to humans being around them so we’ll undertake some preliminary work with dolphins. If that all goes to plan then some of our colleagues from the Murdoch University Cetacean research unit will actually collect these samples for us using their drone systems.
Chris - How much breath do you need?
Garth - It’s been suggested that maybe a single breath from one of these animals or potentially up to 3 or even 5 breaths. But that’s the maximum we’re trying to collect from a single animal so we don’t unnecessarily bother them by flying a drone over them for extended periods of times. So, we’re thinking it’s probably going to give us around maybe 0.1 mil of actual exhaled breath condensate from which we can sample.