Harnessing the eDNA in tidal flows to assess marine biodiversity

In order to have effective management of an environment, we first need to know which species are present. However, sampling a marine environment can be quite difficult - traditional methods such as nets and specialist grabs are both time consuming and can even damage the habitat of the species they wish to observe. Furthermore, the marine environment is quite large, and constantly changing.
Recently, environmental DNA (eDNA) has become a popular method for environmental conservation and species monitoring. It is considered to be an effective, sensitive method, especially for detecting rare, small or evasive species. This method uses DNA fragments left behind by organisms - such as skin cells, faeces and decomposing tissue, to name a few. Essentially, due to advances in bioinformatics and sequencing, it is now possible to take a water sample, amplify the eDNA present, and subsequently sequence samples. These sequences are then used to create a "snapshot" of what species are present in the water body. Potentially, this is a faster and less expensive method than traditional sampling, not to mention less damaging to the environment. The majority of eDNA work in water has been carried out in freshwater systems, with a lesser amount looking at the marine environment, which has its own challenges.
Sampling will be carried out at Strangford Lough, County Down, Northern Ireland. It is the largest sea inlet in the UK, and approximately 2000 species have been observed there. Strangford Lough was designated as Northern Ireland's first Marine Conservation Zone (MCZ), and it has also been named a Special Area of Conservation under the EU Habitats Directive. There are at least 70 small islands, and a number of different habitats. This project will look at each of these habitats and assess the eDNA profile associated with each, over a period of time. In addition, other factors will be investigated to establish whether or not they can affect the eDNA signal - factors such as tidal flows, eDNA persistence times/degradation.
The information gathered from this project can be used to monitor what species are present, and track any changes or trends through space and time. Furthermore, the information gathered could be used to apply better management schemes/strategies. In addition to this, sampling would allow invasive (non-native) species to be detected long before traditional methods could detect them. This is important as it can be very difficult to remove an invasive species once it has been established, and they can have a detrimental effect on native species in the area. The results of this study could potentially be extrapolated to other sea inlets, as well as other marine environments.