Abby Lewis: Freshwater forecasting: A crystal ball for crystal clear water

The following story was written in April 2021 by Miran Seo in ENGL 4824: Science Writing as part of a collaboration between the English department and the Center for Communicating Science.

The picture shows a Virginia Tech student holding a beaker filled with murky river water

Before leaving home during the winter season, particularly when one lives where it might snow or sleet, people check the weather forecast. Doing so provides essential information that helps one choose which shoes to put on, how many layers to wear, and what clothes to take. According to research about people’s perceptions of weather forecasts, people check weather news daily and make a variety of decisions based on weather forecast information. This forecast is especially helpful to people like me, people who are sensitive to the cold.

Many of us are also sensitive to other environmental factors like water quality, mosquito emerging cycles, grasshopper swarm periods, or amounts of pollen in the air. These factors can affect our livelihoods or lifestyles. What if we had a daily forecast for these ecological changes, just as we do with the weather?

Abby Lewis, a second-year Ph.D. student in the Department of Biological Sciences at Virginia Tech, is working to answer this question. Her research on ecological forecasting will help develop daily ecological forecasts so that we can use the information in beneficial ways in various fields.

Lewis grew up in Wisconsin, a state with a natural environment that includes about 15,000 lakes, and she developed a love for aquatic ecosystems at a young age. During her undergraduate education, she held summer research internships in New York and Iceland, and the beautiful lakes and mountains of those areas captured her interest. These experiences inspired a passion for natural environmental research.

If it is possible to forecast ecosystem changes accurately, such as mosquito populations, bird migration, and grasshopper swarm movement, humans could benefit from the information, Lewis said.

"Farmers can potentially use highly accurate predictions of crop pests to target pesticide use to those times,” Lewis explained. “Thereby they can ensure safe food production, and also reduce pesticide-based pollution."

Last summer, Lewis spent time at Falling Creek Reservoir in Vinton, Virginia, collecting water quality and temperature data for her forecasts. In particular, Lewis’s current forecasting research is focused on predicting future oxygen concentrations in the reservoir.

"When you breathe in, you use up a lot of oxygen, and then you breathe out carbon dioxide,” she said. “The same thing is happening in lakes and reservoirs except that it's primarily done by these little guys called microbes, or microscopic organisms."

Lewis explained that high water temperature and oxygen concentration are critical factors to forecast water quality and the reservoir’s ecosystem health. At high temperatures, oxygen will be used faster, and the rate of change in oxygen concentration will be greater.

This photo shows a young Caucasian woman with a blond braid and bangs wearing beige pants, a dark jacket, and an orange life jacket. She is sitting on the back seat of a rowboat on a calm expanse of water with trees in autumn foliage behind her. — Abby Lewis checks the water temperature and oxygen concentration in the Falling Creek Reservoir (Vinton, VA). Photo courtesy of Abby Lewis.

Lewis stresses the importance of designating oxygen concentration to measure water quality, as sufficient oxygen concentration in water is necessary for the organisms living in the water.

"Oxygen concentrations play a critical role in determining a bunch of different aspects of water quality," she explains. Lewis offers one example that we can see in lakes: Fish need oxygen to survive, and when there are low oxygen concentrations, the fish will suffocate and float to the surface.

Other problems related to low oxygen levels in the water include the accumulation of toxic metals and the accumulation of nutrients. While nutrients are not necessarily harmful, they can cause harmful algal blooms. These nutrient-based algal blooms can affect fish and other organisms negatively.

Suppose Lewis can predict oxygen concentration through her research. In that case, a water quality manager will be able to prepare for related water quality problems or prevent them from happening in the first place.

Forecasting about ecosystems cannot be one hundred percent certain because many factors (e.g., unexpected weather conditions, climate change, and human activities) affect what will happen in the future. The researcher's observations are also not perfect, and models used to create forecasts reflect all of the factors of nature. Through the research at the reservoir and her research model program, Lewis focuses on this uncertainty and how it affects her forecast's interpretation. By presenting an accurate assessment of the amount of uncertainty in projections, she helps make sure people using the forecast will have all the information they need to respond to the range of possible scenarios that could happen in the future.

To complete her research, Lewis engages in a range of collaborations on different scales. She now works with five graduate students and three post-doctoral scholars. These researchers have also collaborated with other universities on the same water quality project. Lewis’s goal is to develop forecasts of water quality two weeks into the future. These forecasts will contribute to maintaining safe and healthy water quality.

I can't wait to see the results of her research on ecological forecasting. Five years from now, I might be able to check daily ecological forecasting through my mobile app before drinking tap water or going outside.