It’s a sunny day in the middle of Lake Tahoe when Katie Senft, Carina Seitz and Consuelo Del Rio are aboard the ҹɫÊÓƵ at Lake Tahoe’s research vessel. The research team is testing the quality of water in Lake Tahoe by looking at microplastics, light and other biological parameters. Katie Senft, research faculty for the biology department and boat captain, drives Carina Seitz, a research assistant professor in the biology department at the University and the Tahoe Institute for Global Sustainability, and Consuelo Del Rio, a biology student, a few miles out from the boat dock at Sand Harbor beach in Incline Village, Nevada.
Repetition is key in this boat laboratory. The research team begins the day by running water from different lake depths (surface level, five and 15 meters deep) through a submersible pump, which is lowered to the specific meter level. The water is run through four sieves and into a five-gallon bucket. This filters out all microplastics, big and small. Then, the sieves are rinsed into a small mason jar, capturing enough water (and microplastics) to take back to the lab for testing. 
The team lowers research equipment into Lake Tahoe to get samples of the water.
“We’re looking at microplastics that are coming into the lake near Incline Creek,” Senft said. “We’re doing a transect from near shore all the way out to the middle of the lake to look at plastics floating on the surface and down at different depths.”
This filtering is the task at hand for several hours. The team rotates through directing water into the sieve, controlling the amount of water coming up through the clear pipe or keeping watch from the front of the boat.
Seitz’s research hasn’t always focused on microplastics. She graduated from Universidad Nacional de Río Cuarto with a bachelor’s degree in geology, then graduated from Universidad Nacional del Sur with her Ph.D. in geology, with specialization in paleolimnology, and Limnology. Both are universities in Argentina, where Seitz is from. She’s working with Sudeep Chandra, Ph.D., professor of limnology and faculty member with the Tahoe Institute for Global Sustainability, as a faculty researcher analyzing Lake Tahoe’s clarity and its microplastics. The project is funded by the National Oceanic and Atmospheric Administration and is a joint project with the Desert Research Institute. 
Researchers Katie Senft and Carina Seitz take multiple samples across the lake.
Microplastics aren’t the only culprit affecting lake clarity in Tahoe. Algae growth rises and falls naturally every summer and winter. However, an abundance of phosphorus and nitrogen act as a fertilizer for the lake, meaning algal blooms can get much higher than they should be, negatively impacting clarity.
For the research team, the real fun begins once the sieve sifting is over. Seitz pulls out a LISST 200X, a device that measures the size and count of particles. She carefully lowers into the water over the side of the boat and down to a specific depth. This allows the team to visualize how microplastics and other particles change in size or quantity throughout the water. 
However, this fall, Seitz and the research team are getting an exciting new device, the CytoSub. The CytoSub will allow the team to analyze particles as small as 0.1 micrometers in diameter.
Testing water samples right on the boat ensures the most accurate data.
“One of the CytoSub’s major advantages is its ability to capture not just high-resolution images and particle counts, but also data on how particles interact with light—including light scattering and fluorescence,” Seitz said. “These optical properties help us distinguish between different types of particles, such as very small plankton. With this advanced technology, we’ll gain a faster, more detailed understanding of the biological and physical dynamics shaping Lake Tahoe’s clarity.”
Seitz’s research will conclude toward the end of this year, but future analysis is likely in 2026. In the future, the team hopes to use this equipment to analyze the biological and pollutant components that affect Lake Tahoe’s quality.
