eDNA-based research expanding in Hong Kong
In October 2023, an international eDNA workshop was held at the University of Hong Kong with the support of Croucher Foundation.
Recently, we caught up with Dr Mathew Seymour, the organiser of the workshop, to ask about the impact of that event and his research work using eDNA. This is a topic we have touched on previously, here and here.
If you Google the term eDNA, you might get three rather different answers from three different organisations, depending on their particular interest. So, we started with the question, What is eDNA?
“eDNA, environmental DNA… is genetic material that you extract from an environmental sample. This can include water, soil, air, anything…that interacts with the environment,” Seymour told us.
And why is it so useful? “It’s non-invasive. It’s a way to sample biological information without going in and (for example) collecting or harming fish or destroying habitat. It’s very simple. You just take a small water or soil sample, and you can get all the biological information of everything that’s interacted with that habitat in a simple collection method. You then can combine this with some modern molecular methods to standardise the process of identifying what species are in the sampled environment.”
Of course, the eDNA “signal” doesn’t stay there forever. “It depends on the environment, and it depends on the type of sample. In rivers, for example, it’s short-lived. The strongest signal is where the eDNA originates from in the river, but as eDNA flows downstream, it will degrade and dilute, making detection less likely the further it is from the source. In a lake, particularly in the main water body, eDNA will remain detectable for about a month. The ocean’s a bit trickier. I would still argue that the strongest signal is going to be the most local. But the strong currents, depending on where you are, and Hong Kong has some strong ones, can push the signal around a little bit.”
Seymour has found himself drawn into the use of eDNA quite naturally. “I work with analysing large ecological data sets, which are often needed to ask complex questions but can be difficult to obtain using traditional research methods. My PhD was all about analysing the influence of the environment on insect communities across time and space. My undergraduate and MSc involved population and landscape genetics to understand how populations are shaped by their environment. eDNA allows us to efficiently generate massive ecological data, getting information on hundreds to thousands of species from a single cup of water. My background in ecology and genetics merged well with eDNA, particularly when it was starting to be widely adapted for research.”
eDNA is still quite new, with its early use in biodiversity and conservation studies dating from the early 2000s. It’s become established in North America and Europe and is gaining ground quickly in mainland China. “Hong Kong’s a bit further behind in adopting eDNA approaches,” Seymour told us, which was a reason for his initiating this workshop. “I wanted to give people an opportunity to learn here, to encourage local researchers to learn about eDNA, and provide international eDNA practitioners an opportunity to network.”
The participants were early-career researchers, including PhD students and post-docs, except for one from a research company, and another from a nonprofit organisation. Few had much prior knowledge. Seymour told us that the workshop was deliberately kept at a “beginner” level to make sure nobody was left behind.
“They were mostly ecologists and conservation biologists, because they want to use it for monitoring something that’s directly of interest to them or for more general biodiversity-based applications.”
Although eDNA is still relatively new in Hong Kong, there are some interesting projects being developed. Seymour mentioned he is using it to monitor dolphin populations and marine fisheries around Hong Kong. In fact, his lab is leading several projects to establish eDNA for freshwater biomonitoring in Hong Kong.
“In terms of dolphin monitoring, we’re trying to establish a way to do that regularly in Hong Kong. We’ve been working with a couple of organisations to go out and collect the dolphin eDNA while recording dolphin sightings.”
“We also have several projects looking at biomonitoring and freshwater environments. Hong Kong does not have an established biomonitoring framework to assess water quality. Biomonitoring is an essential part of water quality, environmental services, and habitat monitoring as it provides a direct and routine assessment of biodiversity and pollution effects that are unable to be captured by chemistry-based means. Getting biomonitoring established within Hong Kong is a key interest for me.”
To help build on the progress so far and to build a community, Seymour would like to see more interaction in Hong Kong, and thinks further workshops would be invaluable to the local community.
“I’d like to get a society going to encourage more interactions and push forward some more group projects. We’re also trying to work with local agencies to try and bump up awareness in different sectors. Since eDNA can be highly standardised, it also opens the door for citizen science, enabling locals to get more involved and invested in the process.”
As for the workshop itself, he sees scope for running it periodically. “I’m hoping we can do it every two years, provided we get some funding support. And then, for future iterations, I’m hoping we can continue to update and introduce more advanced methodologies. eDNA is a fast and exciting area of research, so we’re constantly working on new stuff in the lab.”