Automated biodiversity monitoring in the North Sea through eDNA (ZERO-IMPACT)

Is it feasible to detect the presence of marine organisms based on “environmental” DNA (eDNA) in seawater? The ZERO impact project has answered this research question positively. The aim was to develop an innovative, sustainable and automatic method to detect marine species and marine biodiversity in a reliable and less invasive way. There are several advantages to this eDNA technique: 1/ because only seawater is collected to detect the presence of species, the organisms themselves are not disturbed or killed, 2/ only one sampling method is needed to identify different groups of organisms (fish, invertebrates, plankton), and 3/ by autonomous seawater collection, continuous time series for marine biodiversity and fish populations can be obtained.

ZERO-impact has investigated the spatial and temporal patterns of eDNA in the North Sea to efficiently monitor the good status of the marine environment. The potential of eDNA monitoring within the fishing sector was investigated through targeted case studies to map the spawning period of fish, the main period of shellfish spatfall and the presence of toxic algae and harmful parasites near shellfish farming installations. Furthermore, the first steps were taken towards automated sampling of eDNA in seawater.

The project has demonstrated that eDNA provides a non-invasive alternative to typical beam trawl sampling to investigate spatial and temporal patterns in fish communities. Despite the many sea currents in the shallow Belgian part of the North Sea, the project shows that eDNA dispersion is limited and that local patterns in fish populations can indeed be detected. Within the project, dPCR assays were developed for a number of commercially important species such as sole, plaice, whiting and oysters. Quantifying eDNA based on monthly sampling shows that the spawning period of sole in the Belgian part of the North Sea is reflected in eDNA, but that a more detailed sampling design is needed to characterize that spawning period. For detecting toxic algae species, eDNA appears to have a greater resolution than classical flow cytometric analysis. The assays for the oysters and their possible pathogens (Bonamia and Marteilia) have been optimized. There is clear potential to determine the presence of these species with eDNA in the field. Finally, the researchers have succeeded in developing an automatic eDNA sampler that can autonomously filter seawater over time and fix the eDNA. This opens the door to collect eDNA data with high temporal resolution.