Leanne Powers
SUNY College of Environmental Science and Forestry, NY·Chemistry
Sunlight does more than warm lakes and oceans. It drives chemical reactions in the water.
- Fields
Chemistry
Earth & Environmental Science
- Topics
dissolved organic matter
dissolved organic carbon
photochemistry
- Grants
- 3 known grants, through Aug 2028
What they work on
- Measure apparent quantum yields, meaning how efficiently absorbed sunlight produces reactive species, for triplet DOM, singlet oxygen, superoxide, hydrogen peroxide and hydroxyl radical from field DOM and model compounds such as lignin, tannins and flavonoids.
- Test how pH, concentration and added seawater ions change production of reactive intermediates, to find which model compounds and dissolved salts best explain natural DOM photoreactivity and pollutant breakdown.
- Determine the photodegradation rates and products of common organic UV filters from sunscreens, using a custom-built, reproducible sunlight exposure system and mass spectrometry to identify product structures.
- Identify the disinfection by-products formed when sunscreen UV filters react with chlorine in seawater and freshwater, and evaluate whether sunlight and chlorination raise or lower their risk to aquatic organisms.
- Test whether carbon dioxide is really the main product when sunlight breaks down ocean DOC, by co-measuring small compounds such as carbon monoxide, formaldehyde, acetone, pyruvate and acetate in lab experiments and on a 19-day cruise.
- Determine wavelength- and temperature-dependent quantum yields for small carbon photoproducts, and combine them with satellite ocean-color data to model whether sunlight-driven carbon loss is a significant annual sink for marine DOC.
More about the research
Much of this chemistry starts with dissolved organic matter (DOM), the mix of carbon-rich molecules left over from plants, soils and plankton. DOM absorbs most of the ultraviolet light that reaches natural waters. That light energy can break down pollutants, transform sunscreen chemicals, or turn organic carbon into small molecules and gases. These reactions affect water quality and the global carbon cycle. The lab's three projects follow sunlight-driven chemistry from rivers to the open ocean, asking what forms, how fast, and why.
Why it matters
This work could help environmental managers and regulators predict how long pollutants, toxins and sunscreen ingredients persist in rivers, lakes and coastal waters, and whether sunlight or chlorine treatment makes them more or less harmful to aquatic organisms. The ocean carbon measurements may refine estimates of how sunlight removes dissolved carbon from the sea, information that climate scientists and ocean-atmosphere modelers use to predict changes in the global carbon cycle.
Known grants
From NIH and NSF research grants. Labs often have other funding we can't see.
Using a Bottom-Up Approach to Understand Dissolved Organic Matter Photoreactivity
NSF · Sep 2025 – Aug 2028
Collaborative Research: CAS: Environmentally Relevant Photoproducts of Organic UV Filters in Commercial Sunscreens
NSF · Sep 2023 – Aug 2027
Significance of one and two carbon photoproducts in the photolysis of marine dissolved organic matter
NSF · Jul 2023 – Jun 2027
Closest labs
Catherine Clark
Western Washington University, WA·Earth & Environmental Science
Measure the composition and amount of dissolved organic matter (DOM) exported from a salt marsh into the Padilla Bay estuary across tidal cycles and seasons, using spectroscopy, dissolved organic carbon and water-flow measurements.
Winifred Johnson
University of North Carolina Wilmington, NC·Earth & Environmental Science
Identify which marine microbial groups produce which osmolytes under nitrogen stress by pairing osmolyte measurements with transcriptomics in laboratory cultures.
Jonas Baltrusaitis
Lehigh University, PA·Chemistry
Synthesize struvite microcrystals with tailored iron content and characterize their chemical composition and physical properties, to predict how this wastewater-derived fertilizer behaves in the environment.
The school
SUNY College of Environmental Science and Forestry: 1 labs on PI Pages, $39M a year on research, 27 research doctorates a year.
More about SUNY College of Environmental Science and Forestry
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