Overview/Objective
To facilitate the expanded use of hydropower as a reliable and consistent source of renewable energy, researchers at the US Department of Energy’s Oak Ridge National Laboratory (ORNL) are using a novel approach to monitor and determine biological and environmental impacts to aquatic species near hydropower facilities.
Conventional biomonitoring is an invasive, time-consuming, and expensive process of catching and identifying fish and other aquatic organisms to secure DNA samples. By contrast, ORNL researchers in a 3-year pilot study begun in 2020 are collecting DNA from water samples rather than from the organism itself, minimizing the impact to species and habitats. This alternative approach is possible because fish and other organisms shed their DNA into the water as a result of excreting waste, reproduction, or decay. This environmental DNA (eDNA) is then sequenced and compared with a genetic database of known species to identify which organisms are living in and near the water. Another benefit is that these surveys are a fraction of the cost of conventional surveys. A conventional survey to monitor organisms at the Kerckhoff Hydroelectric Dam, for example, cost $294,012, while a comparable eDNA survey at this facility cost only $42,086.
Results
The ORNL research team secured eDNA samples from across four locations at the Melton Hill Dam in the fall, winter, and spring from 2020 to 2021. The initial findings confirmed the effectiveness of the new approach, which successfully detected dozens of common fish species found in previous biomonitoring studies, as well as additional rare species that were not previously detected with conventional methods. Capabilities unique to both approaches suggest that the eDNA surveys could be combined with conventional sampling to provide more comprehensive characterization of aquatic biota.
Impact
Identifying changes in these species and in the overall ecosystem may shed light on environmental impacts of hydropower, and ultimately lead to smarter, more environmentally sustainable facility operation and design.
The novel approach can also be used in multiple applications to do the following:
- Rapidly measure biodiversity
- Detect invasive species
- Detect environmental change
- Detect toxic algal blooms
- Sample difficult-to-access environments
- Determine pollinator–agriculture relationships
- Uncover pollutants
The scope of the project is expanding beyond fish to other aquatic organisms, such as freshwater mussels, invertebrates, algae, and amphibians, including salamanders. Future eDNA research at ORNL will assess the feasibility of determining species’ sex and reproductive status in hydropower biomonitoring studies.
