Hidden by the murky and turbulent waters of the Amazon, the Mekong and the Congo, the biodiversity of the world’s great rivers remains largely a mystery to scientists. But now a multi-million pound project aims to describe and identify the web of life in major freshwater ecosystems around the world with game-changing DNA technology.
The International Union for Conservation of Nature (IUCN) and specialists in environmental DNA (eDNA) based in the United Kingdom NatureMetrics have launched a partnership to take thousands of water samples from freshwater river systems such as the Ganges and the Niger Delta to identify the fish, birds, amphibians and land animals that live in and around them.
Scientists have warned that human behavior is causing the sixth mass extinction of life on Earth, with a million species at risk. Freshwater ecosystems have been disproportionately affected, but conservation efforts are often hampered by a lack of data on the organisms that live in wetlands and river systems.
The $ 15 million (£ 10.6 million) EBioAtlas Programs It will target areas threatened by the climate crisis and human expansion.. The project will fill critical knowledge gaps and establish biodiversity baselines by analyzing genetic material in the water, starting with the Malagarasi river basin in Tanzania that flows into Lake Tanganyika.
EDNA analysis works by genetically profiling feces, mucus, and other matter that organisms shed to establish their presence in an ecosystem. In the United Kingdom, the technique is used to identify the habitat of great crested newt to support conservation work.
In the Peruvian Amazon, electronic DNA profiling of water samples has been used to study the habitat of pink river dolphins and manatees, as well as the web of life that surrounds them, including jaguars, monkeys, catfish and bats.
Over the next three years, the public, private sector and scientists are expected to take some 30,000 water samples from major freshwater ecosystems around the world and pass them through a simple filter kit that will then be analyzed. by NatureMetrics. A kit costs around £ 200 and provides about 200,000 sequences for analysis.
“Our goal is to carry out a global electronic DNA bombardment if we get sufficient funding,” said Will Darwall, director of IUCN’s freshwater biodiversity unit. “We cannot do little things here and there. I think this is a real game changer because identification can be much faster.
“If you are lucky and have clear rivers, as in some cases in the UK, you may see some life under the water. But if you go to a river like the Mekong with giant rays and giant catfish, you will never see them because of the turgid water. What you do not see, you do not miss “.
Darwall said the data will be used to better establish which freshwater species are most at risk of extinction in the IUCN Red List. He said eDNA sampling was much faster than traditional measurement methods such as electric fishing and using nets.
A disadvantage of the eDNA technique is that it relies on DNA barcode reference libraries against which species can be identified. While data exists for some groups of species, barcodes have not been collected for millions of plants, animals, and other organisms.
Kat Bruce, Founder and CTO of NatureMetrics, said she expected the increasing use of eDNA to fuel the growth of DNA barcode reference libraries.
“We are now at a point where there are serious calls for nature and biodiversity to be integrated into global economic models. You just can’t do that if you don’t have the data to back it up, ”he said.
“If you are looking for animals in the UK and Europe, the databases are quite comprehensive, even for insects. It’s a different story in the Amazon, for example, where only about a quarter of the fish species have been identified. But what’s amazing about eDNA is that even if you can’t name everything, you’ve captured the diversity and you have the sequences and you can retrospectively add new names to the data you already have as the references grow, ”Bruce said. .