Perth, Oct 22: A few litres of seawater is enough to reveal hundreds of species living along a coastline, from bacteria to whales, under a UNESCO program launched today at the UN Biodiversity Conference, COP17.
The eDNA Expeditions program, funded by the Perth-based Minderoo Foundation, will support local teams at 25 marine sites worldwide to sample their waters repeatedly over three years, from 2026 to 2028.
Environmental DNA, or eDNA, is the genetic material that living things shed into the water around them. Teams collect it by filtering seawater through a syringe and a small handheld filter, with no harm to the environment.
“From a single litre of filtered water, we can identify on average 100 species, and there’s no limitation on the type of species we can detect,” said Saara Suominen, an eDNA program specialist at UNESCO’s Intergovernmental Oceanographic Commission.
“All organisms leave traces behind. That’s from bacteria to whales.”
That includes sharks. Asked by DailyStraits whether eDNA could detect them, Suominen said the project’s lab partner, Wilderlab, analyses each sample with 13 genetic markers to capture “the whole tree of life”, which “definitely includes sharks”.
Children as young as six
A pilot phase at 21 Marine World Heritage sites showed that citizen scientists, including children as young as six, could collect reliable samples. About 500 samples identified more than 4,000 species, including 120 on the IUCN Red List of threatened species.
The new phase aims to collect about 3,000 samples by 2028, seven times more than the pilot. So far, 208 samples have been collected, and the first 100 sequenced have already identified 1,800 species. Results reach local teams in about a month.
Ward Appeltans, head of UNESCO’s Ocean Biodiversity Information System (OBIS), said school students sampling Aldabra Atoll in the Seychelles detected more than 800 species in just a few litres of water, including 13 sharks and rays, some not previously known to be there.
“If you just show them a list of 800 names, that’s not the same as showing 800 pictures,” he said.
From Mexico to Greenland
Local teams decide what to study. In Huatulco National Park on Mexico’s Pacific coast, the focus is marine heatwaves, coral bleaching and invasive species arriving on ships. In Iligan Bay in the Philippines, a brigade of former fishers known as the Bantay Dagat, or sea guardians, will help build the bay’s first systematic biodiversity baseline.
Tales Carvalho Resende of UNESCO’s Marine World Heritage Programme said at least five very remote World Heritage sites would also be sampled, including the French Austral Lands and Seas in the southern Indian Ocean, which can be reached only a few times a year.
In Greenland’s Ilulissat Icefjord, local fishers have reported fish and whales appearing where they were rarely or never seen before, as Arctic waters warm.
“Even a few litres of seawater can really tell us a great deal about the marine life that is there,” Carvalho Resende said.
Limits of the method
eDNA shows which species are present, but not how many. Sampling is limited to coastal waters no deeper than 15 metres, and Suominen said the method is meant to support, not replace, traditional surveys such as diving.
Local communities keep ownership of their data, which is quality-checked by local experts and then shared openly on OBIS.
UNESCO did not name any Australian sites during the briefing. The full list of participating sites is on the eDNA Expeditions website, and more sites are expected to join.
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