Meet EPA Ecohydrologist J. Renée Brooks, Ph.D.
EPA researcher J. Renée Brooks works on understanding how stable isotope ratios of biologically important elements—Hydrogen (H), Carbon (C), Nitrogen (N), and Oxygen (O)—can help understand ecohydrological processes that influence the condition of the nation’s waters. Isotopes are atoms of the same element that have the same number of electrons and protons, but different numbers of neutrons. An extra neutron on an element means it moves slower and bonds more strongly. Because of these differences, stable isotope ratios measured within samples integrate, indicate, record, and trace fundamental processes in hydrology and ecology.
What research are you working on right now?
Currently, I am figuring out how stable isotopic ratios can help evaluate the condition of the nation’s waters by applying them to EPA’s National Aquatic Resource Surveys (NARS). For example, my most recent publication (Brooks et al. 2022) focuses on the nitrogen isotope ratio (15N/14N, denoted as δ15N) in aquatic insects collected from survey samples of lakes, rivers, and streams across the country. Measuring the δ15N in aquatic insects along with the total N concentration in streams helps identify places where agricultural fertilizer is moving into streams unimpeded, and places where ecosystems are cycling and removing much of that N before it reaches the aquatic systems. This indicator helps land managers and farmers identify which watersheds are providing the valuable ecosystem service of nitrogen retention and removal, and which watersheds need to be improved.
Tell us about your background.
My undergraduate degree was at the University of Georgia in the School of Forestry majoring in forest hydrology. My master’s degree and PhD were from College of Forest Resources at the University of Washington, specializing in tree physiology, where I climbed into forest canopies of the Pacific Northwest. My postdoctoral experience at the University of Utah opened the world of stable isotopes in ecology to me. All these educational experiences have been critical components to becoming an ecohydrologist using stable isotopes to understand our environment.
When did you first know you wanted to be a scientist?
My path to becoming a scientist was an evolution over time. Camping trips in Oregon in my youth exposed me to the dramatic changes water can induce in ecosystems from the coastal rain forest to inland deserts. I was fascinated by how water influenced the shape of ecosystems and led me on the educational path I outlined above. My first summer job in my freshman year at college was with Georgia’s Environmental Protection Division with the Clean Lakes Program. I learned all about collecting water quality data in lakes and spent my summer on boats in the middle of lakes all over the state. I really enjoyed it and realized I could make a career doing this type of work.
What do you like most about your research?
I love graphically analyzing data and seeing patterns. I love the “Aha!” moments when looking at data and gaining understanding and insights into ecological systems that I didn’t have before. I also like sharing these insights and working with others to learn about stable isotope analysis and how they can be applied to different research questions.
How does your science matter?
This research contributes to science at both national and local levels. The NARS program is how EPA reports to congress on the condition of the nation’s water as required under the Clean Water Act. In partnership with states and tribes, field crews sample approximately 1000 sites every year, collecting physical, chemical, and biological data and samples during a single-day visit. However, many important ecological processes cannot be measured in a single day visit and would be prohibitively expensive to attempt as part of NARS. Measuring stable isotope ratios on samples that are already collected as part of NARS offers insights into these critical processes and expands the information available for making assessments on the condition of our nations water resources. I also apply isotopic techniques to many more local and regional nutrient and water quality problems, like helping farmers determine better fertilizer applications.
If you weren’t a scientist, what would you be doing?
Hard to imagine following a different path from what I did. When I think about what I love to do, I love creating and teaching. I gain inspiration through walking in different ecosystems, from urban to wilderness, and being curious about my surroundings. With my science, I create new understanding of those ecosystems through data analysis, and then teach others. I also love creating things with my hands through sculpture, cooking, and gardening.
What advice would you give a student interested in a career in science?
Be curious and remain open to many opportunities. Don’t be afraid to put yourself out there and contact scientists that inspire you. In addition to loving science, connections and collaborations are important keys in a successful science career.
If you can have any superpower, what would you choose?
I would love to fly or float up into forest canopies and look at watersheds. When I was a graduate student at the University of Washington, we worked hard to gain access to forest canopies by building canopy towers and I always thought how cool it would be to just fly. Since then, I’ve accessed canopies through the Wind River Canopy Crane (now dismantled) and through rope climbing, but what if I could just fly up there? Now my focus has spread to watersheds and river basins, and that aerial view is so important for understanding water flowpaths.
What do you think is our biggest scientific challenge in the next 20/50/100 years?
Without a doubt, our biggest challenge is addressing climate change. While I’ve talked and taught about it for decades, the last few years have illustrated what words could not. In September 2020, the Willamette Basin experienced three massive wildfires related to climate change, and while my home was safe that time, most of the population of Oregon was forced to remain inside from the toxic wildfire smoke. Last June, we experienced an unprecedented heat dome with temperatures topping 110 F during a period that is usually wet and cool. The impact of that heat dome on our native trees and vegetation was highly visible through foliage scorch. The scientific challenge of climate change is now and for the next 20/50/100 years.
References
Brooks, J. R., J. E. Compton, J. Lin, A. T. Herlihy, A. Nahlik, W. Rugh, and M. Weber. 2022. d15N of Chironomidae: An index of nitrogen sources and processing within watersheds for national aquatic monitoring programs. Science of the Total Environment 813:151867.
Editor's Note: The opinions expressed herein are those of the researcher alone. EPA does not endorse the opinions or positions expressed.