Environmental DNA, or eDNA, is an emerging technology that enables scientists to map all the organisms in a river or lake with a small water sample. For around US$50-150, you can learn from one sample all the species passing by the river from a kilometre upstream within the last 24-40 hours. Previously, it took highly intrusive and time-consuming methods to understand species distribution. In comparison, eDNA is more sophisticated (requiring just a single cell of genetic material from an organism), cheaper and easier.
The next step in the technology's development would to more beyond gauging species distribution to estimating species abundance based on the DNA quantities in samples.
Conservation efforts have traditionally been painstaking and expensive. Even today, many species numbers are monitored using sampling methods and the tracking of individual organisms. With eDNA, a better mapping of river organisms can mean a more holistic understanding of the river ecosystem - thereby leading to more targeted conservation and a real-time understanding of the ecosystem impacts of conversation efforts. The technology is particularly useful for understanding invasive species distribution in one water body, the genetic diversity of fish stocks and the success of reintroduced native species. Furthermore, the DNA of species populations better adapted to environmental conditions such as warmer waters can be identified, studied and relocated.
The impact eDNA can have on conservation could also be more powerful due to the growth of citizen scientists. With the help of low-cost detection kits, more people than ever before - students, nature enthusiasts and volunteers - are now taking water samples, sending them to a university for analysis and then entering the mailed results into a database. A growing worldwide database in the future can also inform environmental impact assessments, being used as further proof points to take big polluters to task.