NSF Award
2406856
The use of environmental DNA (eDNA, or genetic material shed by organisms) to measure biodiversity is a revolutionary approach that transforms the ability of biologists to observe biodiversity on Earth. In freshwater environments, eDNA in just a liter of water can indicate what fish, insects, and bacteria are present. Despite the rapid advances and adoption of this approach, very little is known about how long eDNA lasts and how fast it disintegrates in nature. Understanding the fate of eDNA in streams and rivers presents a major challenge for interpreting an eDNA “hit”. This NSF award, known as the "DISTANCE" project, will address this knowledge gap by studying the environmental factors that promote or inhibit eDNA movement and degradation in U.S. streams, especially those that are part of the National Ecological Observatory Network (NEON). Infrastructure of the NSF-funded Emerge training program, which broadens undergraduate and graduate student participation in freshwater science, will be expanded as part of the DISTANCE project. Opportunities for student and postdoctoral training will be integrated into the research studies. <br/><br/>The term “eDNA spiraling” has been used to describe the fate of eDNA as it flows downstream, where it can be degraded by microbes, deposited in streambed sediments, resuspended from the streambed, and transported further downstream. Hypotheses will be tested that relate water chemistry, microbial communities, and hydrogeomorphology to the three major processes driving eDNA fate: degradation, deposition, and transport. NEON infrastructure will be leveraged by conducting eDNA spiraling experiments at NEON stream sites. Replicated eDNA spiraling experiments will be conducted in two NEON streams and one Critical Zone Observatory site to determine how the type of eDNA (i.e., originating species) and eDNA particle size distribution (determined through sequential filtering) influence eDNA spiraling metrics. Fish and macroinvertebrate biodiversity assessments will be paired at NEON sites with eDNA metabarcoding to investigate whether eDNA spiraling metrics can predict the congruence of community data generated by eDNA metabarcoding compared to traditional methods. DISTANCE has three broader impacts. First, infrastructure of the NSF-funded Emerge program, which broadens participation in freshwater science, will be expanded. Emerge trains undergraduate, graduate, and early career scientists from underrepresented groups in data analysis and visualization (using R software) and in collaborative science. Training in data analysis and visualization for Emerge alumni will be expanded by offering in-person workshops on “Introduction to bioinformatics of eDNA and DNA metabarcoding data.” Workshops will follow The Carpentries pedagogy and be made open access for other Data Carpentries instructors to teach. Second, we will extend NEON infrastructure by generating new, open-access eDNA datasets for NEON sites. Third, this work will provide training experiences for undergraduate students, graduate students, and one postdoc funded by the project, giving them opportunities to practice teaching and mentorship themselves, as implemented in a hierarchical mentoring plan.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
