DNA-based tools boost marine coastal management
Around 60 % of the global human population lives on or near the coast. In some countries like Australia, this figure is closer to 85 %. Inevitably, this means that the pressures placed on marine coastal areas can be extreme. “Coastal environments host unique species assemblages and perform critical functions,” notes TEAM-Coast project coordinator Johan Pansu, lecturer at the University of Montpellier, France. “These include ecosystem services such as water purification and carbon sequestration. Salt marshes and mangroves for example capture lots of atmospheric carbon.” Coastal areas are also vital economically, maintaining fisheries and often playing a key role in tourism. “Basically, these are areas where a lot of people live, and which provide unique services to humankind,” says Pansu. “This is why we have to find ways of reducing our impact.”
Monitoring marine biodiversity
The TEAM-Coast project, which was coordinated by the French National Centre for Scientific Research and undertaken with the support of the Marie Skłodowska-Curie Actions programme, aimed to develop new ways of assessing the impact of human activities on marine biodiversity. “The result of such activity has often been difficult to capture,” explains Pansu. “Observations have often been limited to a small number of species. We might study fish and crustaceans, but we then miss out on a large fraction of biodiversity.” Integrating different pressures on biodiversity has also proven to be problematic. “Most impact assessments look at one contaminant or pressure at a time,” says Pansu. “This however ignores potential interactions and combined effects.” The TEAM-Coast project sought to overcome these issues with DNA-based tools and statistical modelling. “All living organisms leave behind some DNA,” explains Pansu. “So, a bit like forensic police we collected environmental samples, mostly sediment and water in this case, and from these samples extracted DNA.” These samples were collected off the Australian state of Queensland, home to the Great Barrier Reef and an incredible array of marine biodiversity. In the lab, DNA fragments, called DNA barcodes, that can provide information on species identity, were then targeted and sequenced. These barcodes were then compared with existing reference databases. “This approach allows for potentially characterising the diversity of all life forms, from bacteria to animals, without capturing or targeting any specific specimen,” adds Pansu. In the second part of the project, the team applied this data to statistical models. “We wanted to be able to weigh the impact of different stresses, such as contaminants and pesticides, on biodiversity,” remarks Pansu. “Our aim is to develop a template that can then be used in other environmental contexts.”
Measuring human impact
The key success of the TEAM-Coast project has been to demonstrate the effectiveness of this DNA-based approach for measuring biodiversity impacts. The technique enabled Pansu and his team to characterise and study virtually all communities within a sample – bacteria, plants, fish, crustacea etc. – in a comprehensive, rapid and cost-efficient way. “We could then use this data to make semi-predictive models,” he adds. “By proposing to reduce, say, pesticide contamination by half, we can predict what the expected change in biodiversity might be.” This tool could therefore help environmental managers and policymakers to better understand the balance between ecosystem health and human activity and make more informed and environmentally aware decisions. The tool could also be used for ongoing monitoring, to ensure that Europe’s critically important – and fragile – coastal areas continue to flourish.
Keywords
TEAM-Coast, marine, biodiversity, coast, carbon, mangrove, DNA
