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Whales are wonderful, charismatic animals whose majesty and near mythological size have always drawn human interest. Studying whales, however, comes with its share of challenges.
Whales spend much of their time below the surface, making it difficult to learn about their lives, health and habits. Many methods of study can also be disruptive and cause them stress. Science is thus constantly innovating technology to study animals and ecosystems in non-invasive ways with minimum disturbance. One such approach involves collecting genetic samples from the environment, rather than directly from the animal. For my research, this means… whale poop!
I extract DNA from whale poop (or faecal) samples to learn more about these beautiful creatures. The DNA present in whale poop comes from different sources – there is the whale’s own DNA, along with DNA from prey animals the whale has been feeding on, and lots of DNA from the bacteria that live in the whale’s gut that help it digest its food! I use these DNA samples to answer a few questions that can tell me quite a lot about the whale’s lifestyle and health.
For example, what is the whale eating? And based on this, where does it need to go to find its prey of choice? What happens if the krill it likes to eat most start dying out because of climate change?
What is the composition of its gut microbiome, or in other words, what are the different bacterial communities living in its gut? This gut microbiome should be fairly similar across all the whales belonging to one species. If some whales are different, this could indicate that they are stressed or unwell. As you can see, we can get a lot of information from a tiny (or huge!) sample of poop.
Ultimately, the whale is an integral part of the ocean ecosystem. Its poop provides lots of nutrients to the marine environment which help krill and plankton multiply. These krill and plankton then serve as food sources for so many other species, including the whales themselves!
This concept of balance between different species can translate across diverse ecosystems, and I use the Arludo video game, Quokkapocalypse, to help students explore this. In Quokkapocalypse, players take the role of ecosystem managers that must identify the connections between different species and resources in various ecosystems.
Using their trusty giant quokka, players can control the populations of some species to allow others to increase. Finding balance between predator and prey becomes more complex with each level as more factors are thrown into the mix.
The intricacies of ecosystem balance hold our planet together and are evident all around us. Tuning into the many connections between elements of an ecosystem can not only deepen our appreciation towards the natural world but also help us better understand and address the many risks she faces.
Written by Aashi Parikh
Aashi is a PhD candidate in the environmental DNA lab at Macquarie University. She is studying whales through their poop – extracting DNA from faecal samples to learn about the whales, their prey and their gut bacteria.