Tiny indicators of big problems

The tiniest organisms living inside the guts of Antarctic seabirds can give us much vital information. Understanding the changes in gut microbiomes in animals and studying their poo over time can provide early warning of dramatic environmental changes – including toxins, diseases, food availability and climate change, says Federation University researcher Dr Meagan Dewar.

“It helps us understand changes in the microbial community and whether we are introducing things into the environment, and if migratory species are introducing things as well and how environmental change influences the microbes that are present,” she explains. “By doing disease surveillance, we can start to see if things are showing up or changing.”

An expert in host-microbiome interactions and pathogen and disease surveillance, Dr Dewar has worked with several national agencies in Antarctica, including French, British and Australian, in this world-first research. But she is not restricted to Antarctic species, having also studied microbiomes in koalas, seals and, now, sharks off the NSW coast.

After graduating as a marine biologist, Meagan took on an honours project studying the stress levels of little penguins during a research technique called stomach flushing. Noticing that the same tube was used with different birds, she began to wonder if this could spread diseases and how to mitigate the risks associated with the procedure. “And so,” she says, “I discovered the wonderful world of microbes and understood the important roles that microbes play.”

After learning that the last research on microbes in penguins was done in the 1970s, she completed a PhD on gut bacteria in penguins and other seabirds. This has led to work on the genetic sequencing of seabird poo to spy on the microbes of penguins, procellariiform seabirds, seals and sharks, and a $148,000 Australian Antarctic Science Grant to analyse samples collected from several Antarctic seabird species over the past 20 years.

“On a lot of our sub-Antarctic islands, we are seeing evidence of disease such as avian cholera, but little is known about East Antarctica.” Dr Meagan Dewar

During the worldwide COVID pandemic, fears were held for animals in Antarctica – the only continent free of COVID infection – as the COVID virus is known to be able to cross species. It could be possible that tourists or researchers in the Antarctic could spread the disease. So, as well as conducting searches for any signs of COVID infection in Antarctic species, Dr Dewar and colleagues studied the likelihood that the animals there would become infected.

“We know COVID can jump species, with cases being found in farmed minks, as well as domestic cats and tigers,” she says. “Based on the information we know about their biology and the virus’s cell structure, seabirds have a very low risk of contracting COVID. Whales have a relatively high risk but a low risk of exposure. Seals seem to have a relatively low risk as well.”

One of Dr Dewar’s current projects, funded by the Agreement on Conservation of Albatrosses and Petrels, is to develop portable disease surveillance techniques that can be rapidly applied in the field, rather than waiting weeks or even months to get results back from a laboratory. This could be particularly vital if, for example, there was a mass death event of many birds.

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