Anshula Dhiman, a Cleveland State University graduate student, is developing a tool to help scientists distinguish between muddy water and algae-rich water, a critical step in tracking the nutrients that fuel harmful algal blooms, including in Lake Erie.

Dhiman, an international student who is pursuing a Ph.D. in regulatory biology while working as a research assistant, is focused in her research on “mass-specific backscattering partitioning and associated phosphorus dynamics from hyperspectral observation.”

Hyperspectral observation uses hundreds of tiny bands of light—far more than the human eye can detect—to take highly detailed images of water and reveal what’s in it, such as algae or sediment. Backscattering partitioning then builds on that by analyzing how light reflects off those particles and separates the signals to determine exactly what is causing the cloudiness.

In short, Dhiman separates images of sediment-rich water from algae-rich water, then uses that information to monitor phosphorus levels, which can contaminate water, in this case the water in Lake Erie.

Her research builds on previous NASA-funded work that examined the extent to which phosphorus originates within a lake. Internal phosphorus can significantly affect water quality by contributing to algal blooms.

“We have harmful algae blooms each year in the summer season,” Dhiman said. “Most of it is tied to how much phosphorus is available.”
 

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Dhiman completed two of her master’s degrees in India, where she has long been passionate about environmental science and the study of natural systems. She said her curiosity about the unseen processes in nature – and how even the smallest particles in water can reveal critical information – motivates her research.

“It’s very interesting to see all these processes happening in the system… the tiniest particle in the water would tell us more than we think,” Dhiman said. “So that’s what drives me.”

Dhiman’s current research focuses on phosphorus dynamics in Lake Erie and how the nutrient contributes to harmful algal blooms each summer. 

While phosphorus is typically a limiting nutrient in freshwater ecosystems, decades of agricultural runoff have increased its levels in the lake, fueling blooms. Much of that phosphorus has settled into the bottom sediments over time.

Her work examines how wind and large wave events can disturb those sediments, releasing stored phosphorus back into the water. Dhiman has developed estimates of the amount of phosphorus that could be released during these resuspension events and has learned how these events may influence the severity of the blooms.

“I have this manuscript for the work that I’m doing because when we have an event, a wind event or a wave, it resuspends all the sediments that are there in the bottom.” Dhiman said. “That releases the phosphorus from those sediments and this phosphorus could be tied to the severity of the harmful algae blooms.”

Dhiman said her research is ultimately driven by a desire to improve water quality and assist the community. 

Though officials closely monitor how much phosphorus enters Lake Erie from rivers and agricultural runoff, she said those efforts do not fully account for the amount of phosphorus released from sediments already in the lake, a gap in our understanding of the lake's dynamics she wants to close.

“I really want to help the community,” Dhiman said. “We have authorities checking how much phosphorus is getting into the system, but it's not doing much.” 

What began as a long-standing fascination with environmental science has grown into a commitment to ensuring her work has a practical impact. With plans to complete her Ph.D. in 2027, Dhiman said she hopes her research will contribute to more informed decisions about managing Lake Erie’s water quality.

As Dhiman progressed through her research, she said she began thinking more intentionally about how her findings could move beyond academic journals and truly help people. 

“Research is not just for yourself,” Dhiman said. “It is also finding things which would benefit other people.”