2014 Research Experience for Undergrads
My name is Sophia Wensman. I am a Secondary Education student in the School of Education at the University of Michigan double majoring in Chemistry and Earth/Space Science.
This year I was very fortunate to be one of six students accepted to the University of Washington's Joint Institute for the Study of the Atmosphere and Ocean (JISAO) REU internship program. As a 2014 JISAO summer intern, I had the opportunity to work with Drs. Bonnie Chang, Rolf Sonnerup, Calvin Mordy, and Mark Warner. My project focused on the production and emission of nitrous oxide (N2O) from Hood Canal in Washington.
Nitrous oxide is a powerful greenhouse gas with a warming potential molecule for molecule of approximately 300 times that of carbon dioxide. Despite its climatic significance, the magnitude and production mechanisms of marine N2O production are not well known. Nitrous oxide emission from the world’s oceans is responsible for 25 – 30% of global inputs to the atmosphere. Up to 61% of the ocean source is from coastal environments where productivity is often intensified due to the upwelling of deep nutrients or runoff from land. This production eventually sinks, resulting in high respiration rates at depth. Byproducts of respiration (NH4+) are oxidized by microbes to N2O through a process called nitrification. Additionally, in low oxygen (O2) environments N2O production by nitrification is enhanced and eventually when O2 is fully depleted, anaerobic microbes reduce nitrate (NO3=) to N2O during the oxidation of organic matter. This process is called denitrification.
The location of our study was Hood Canal. It was chosen because it is a highly productive fjord, with restricted circulation, which results in the development of hypoxia during a typical summer. These factors suggest that Hood Canal may be a significant source of N2O emission. The goals of this study were to quantify the air-sea flux of N2O from Hood Canal and determine the processes that produced it.
I began my summer by going on a 3-day research cruise to Hood Canal. We obtained CTD data and water samples from a variety of depths at fifteen different stations.
After the cruise ended I began analyzing the water samples we had collected. I worked with Mark Warner in his laboratory using gas chromatography and electron capture detection. Through this process I was able to quantify the concentration of N2O in the water samples taken during the cruise.
I then worked at the National Oceanic and Atmospheric Administration (NOAA) Pacific Marine Environmental Laboratory (PMEL) in Calvin Mordy’s lab with the help of Eric Wisegarver, who taught me how to use a Technicon Autoanalyzer. This instrument separates the water by nutrient and uses a spectrometer to determine the concentration of those nutrients present in the water sample.
The results of the data collected from the cruise to Hood Canal indicate that Hood Canal is indeed a source of N2O to the atmosphere, and that nitrification is the primary process driving the production of N2O in Hood Canal.
I’d like to thank Dr. Tom Ackerman and Dr. Philip Hoffman for the opportunity to conduct research at the University of Washington this summer. Additionally I want to express my gratitude to my mentors and Jed Thompson who provided endless support and guidance over the course of the summer. My internship was an incredible learning experience and I thoroughly enjoyed the time I spent in Seattle.
Click on image for PDF