What is eDNA?
Coastal waters teem with DNA. Even the smallest organisms shed genetic traces of their presence through things like skin cells, hair, scales, feces, or mucus. All of this “environmental DNA”, known as eDNA, can easily be collected and analyzed from samples of water, air, sediment, soil, or snow—allowing us to track what organisms are present in the environment.
These eDNA samples are relatively easy to collect, do not require expert knowledge in taxonomic identification, and are increasingly low-cost to analyze. This makes eDNA a great tool for everyone from citizens to veteran scientists to rapidly assess and monitor biodiversity across space and time and detect rare or invasive species.
When employing eDNA in biodiversity monitoring, two major approaches are used:
DNA metabarcoding is useful if you want to get a picture of whole communities of fish or invertebrates or other groups of organisms in the environment.
Quantitative PCR (qPCR) is used to target the DNA of a species of interest and quantify how many copies of that organism’s DNA are in your sample.
What do we use it for?
Analyzing eDNA is ideal for:
Biodiversity monitoring: Quickly and non-invasively surveying species richness, diversity and community composition
Invasive species tracking: Early detection of invasive species before they become established to enable rapid and effective response
Conservation and management: Locating and tracking rare or endangered species without dramatically disturbing their habitat
Monitoring ecosystem health: Supporting efforts to evaluate an ecosystem’s ability to maintain its structure, function, and services through biodiversity assessments
Biosurveillance: Detection of pathogens, harmful algal blooms, or parasites that could negatively impact organismal and ecosystem health
The five stage workflow
This monitoring method will walk you through the basic steps necessary to set up and carry out an eDNA study in a marine environment. It consists of the following stages:
