Aquatic Photochemistry

at Woods Hole Oceanographic Institution

Research Projects

Crude Oil

Sunlight alters the chemical and physical properties of crude oil spilled into marine environments. These alterations to oil properties impact how well chemical agents, like dispersants, perform in response to oil spills.

Dissolved Organic Matter

Sunlight can completely oxidize DOM into CO2, a greenhouse gas, and partially alter DOM into new compounds. These alterations impact the lability of DOM to microbes. Most of our DOM work focuses on permafrost DOM draining arctic soils.


Plastics are an emerging pollutant. We want to understand how long plastic consumer goods last in the environment. To do so, we characterize the rates, pathways, and products of plastic degradation by sunlight in the environment.

Instrument Development

We’re building a system that can measure rates of photochemical oxidation, microbial respiration, and photosynthesis in the water column.

The Ward Lab

Our state-of-the-art laboratory at the WHOI focuses on characterizing the prevalence, pathways, and products of the photochemical degradation of organic carbon in aquatic ecosystems. We study lots of different types of organic carbon, including naturally derived organic carbon, like dissolved organic matter and black carbon, and man-made pollutants, like crude oil and plastics.


  • Ward, C.P., Armstrong, C.J., *Walsh, A.N., *Jackson, J.J. & Reddy, C.M. Sunlight converts polystyrene into carbon dioxide and dissolved organic carbon. In press at Environmental Science & Technology Letters.
  • Ward, C.P., Sharpless, C.M., Valentine, D.L., Aeppli, C., *Sutherland, K.M., Wankel, S.D. & Reddy, C.M. Oxygen isotopes (δ18O) trace photochemical hydrocarbon oxidation at the sea surface. 2019. Geophysical Research Letters12, 6745-6754.
  • Ward, C. P., Armstrong, C. J., Conmy, R. N., French-McCay, D. P., & Reddy, C. M. Photochemical Oxidation of Oil Reduced the Effectiveness of Aerial Dispersants Applied in Response to the Deepwater Horizon Spill. 2018. Environmental Science & Technology Letters.
  • Ward, C.P., Sharpless, C.M., Aeppli, C., French-McCay, D.P., Valentine, D.L., Rodgers, R. P., Gosselin, K.M., Nelson, R.K., & Reddy, C.M. Partial photochemical oxidation was a dominant fate of Deepwater Horizon surface oil. 2018. Environmental Science & Technology, 52 (4), 1797-1805.
  • Ward, C.P., Nalven, S.G., Crump, B. C., Kling, G. W., & Cory, R. M. Photochemical alteration of dissolved organic carbon draining permafrost soils shifts microbial metabolic pathways and stimulates respiration. 2017. Nature Communications8, 1-8.