© 2018 by Janelle E. Letzen, PhD

 
Oysters and Water Quality
Meet the Scientist

I’m Melanie Jackson (@mermelaniejo on Instagram), and I’m a PhD candidate at the University of Maryland Center for Environmental Science studying how oysters improve water quality.

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Science Snack

The Chesapeake Bay has too much nitrogen pollution from fertilizer runoff and other sources, which fuel algae blooms and can result in dead zones. 

The Chesapeake Bay has too much nitrogen pollution from fertilizer runoff and other sources, which fuel algae blooms and can result in dead zones. 


My research determines how much nitrogen pollution can be removed by oyster restoration and aquaculture, since a single oyster can filter up to 50 gallons of water per day!

Oysters remove nitrogen by eating algae and storing the nitrogen in their tissues, but my research focuses on a different way that oysters remove nitrogen, called denitrification. 

Sushi Science | Janelle Letzen | Oysters

Oysters create the ideal environment for denitrification, where bacteria convert nitrogen pollution to a nonharmful gas (N2) that goes into the atmosphere, which eliminates the nitrogen from the water completely! Yay Denitrification!

The rates of denitrification I measure from oysters will help inform policy on whether oysters planted for restoration or aquaculture can be used as a best management practice to help clean up Chesapeake Bay.

References

[1] Cornwell, J., Rose, J., Kellogg, L., Luckenbach, M., Bricker, S., Paynter, K., ... & Lacatell, A. (2016). Panel Recommendations on the Oyster BMP Nutrient and Suspended Sediment Reduction Effectiveness Determination Decision Framework and Nitrogen and Phosphorus Assimilation in Oyster Tissue Reduction Effectiveness for Oyster Aquaculture Practices. DRAFT for CBP Partnership and Public Review.

[2] Hagy, J. D., Boynton, W. R., Keefe, C. W., & Wood, K. V. (2004). Hypoxia in Chesapeake Bay, 1950–2001: long-term change in relation to nutrient loading and river flow. Estuaries, 27(4), 634-658.

[3] Kemp, W. M., Boynton, W. R., Adolf, J. E., Boesch, D. F., Boicourt, W. C., Brush, G., ... & Harding, L. W. (2005). Eutrophication of Chesapeake Bay: historical trends and ecological interactions. Marine Ecology Progress Series, 303, 1-29.

[4] Grizzle, R. E., Greene, J. K., & Coen, L. D. (2008). Seston removal by natural and constructed intertidal eastern oyster (Crassostrea virginica) reefs: a comparison with previous laboratory studies, and the value of in situ methods. Estuaries and coasts, 31(6), 1208-1220.

[5] Newell, R. I., Fisher, T. R., Holyoke, R. R., & Cornwell, J. C. (2005). Influence of eastern oysters on nitrogen and phosphorus regeneration in Chesapeake Bay, USA. In The comparative roles of suspension-feeders in ecosystems (pp. 93-120). Springer, Dordrecht.

[6] Piehler, M. F., & Smyth, A. R. (2011). Habitat‐specific distinctions in estuarine denitrification affect both ecosystem function and services. Ecosphere, 2(1), 1-17.

[7] Kellogg, M. L., Cornwell, J. C., Owens, M. S., & Paynter, K. T. (2013). Denitrification and nutrient assimilation on a restored oyster reef. Marine Ecology Progress Series, 480, 1-19.