Digest this!

Fig 1. My experimental set-up when performing digestions in the Agroecology lab

Today marks the end of my time as an intern in the Agroecology Lab. I have been fortunate enough to spend the entirety of my senior year working in the lab with Dani Weissman and the other graduate students, Cullen McAskill the wonderful lab technician, and my fellow interns. Through my various research experiences in the lab, I have learned so much about biogeochemical cycling processes that impact agriculture, the importance of agroecology to integrate ecological and social approaches to agriculture, and standard chemical analysis research practices.

This semester I focused my efforts on a long-term research study to understand different nutrients, like nitrogen and phosphorus, that are dissolved and bound to soil particles in water samples taken from various agricultural plots on the Eastern Shore. Nitrogen in this form is formally called “Dissolved Organic Nitrogen” (DON), while other forms of nitrogen often found in the soil include nitrate and nitrite, which are necessary for plant growth. The agroecology lab is investigating these different forms of nutrients because it is important to understand how changing environmental conditions may impact the future of agriculture. Rising sea levels, for example, is causing saltwater from the ocean to intrude into agricultural plots on the Eastern Shore. This alters the chemical and biological processes that take place in agricultural soils (Osburn, 2016; Weston, 2006). To understand how nutrient forms have been changing over time in response to saltwater intrusion, I conducted digestion experiments on water samples to specifically target dissolved organic nutrients. Essentially, the experiment required me to add various chemicals to the water samples (as shown in Figure 1) and then run them through an autoclave, which heats the samples up to extremely high temperatures. This breaks up any bonds between the nutrients and dissolved soil components to isolate the nutrients to be further analyzed.

The results of this experimental digestion process will provide important information on plant nutrient availability once they undergo a next step of further chemical analysis. It is a good feeling to be able to contribute to the research findings of the Agroecology Lab. I will sorely miss my time working there now that the semester has come to a close, but I will be forever grateful to all that I have learned and for how it has changed my perspectives of agroecology.

References:
Osburn, Christopher L., Lauren T. Handsel, Benjamin L. Peierls, and Hans W. Paerl. 2016. “Predicting Sources of Dissolved Organic Nitrogen to an Estuary from an Agro-Urban Coastal Watershed.” Environmental Science & Technology, 50: 8473-8484.
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Weston, Nathanial B., Ray E. Dixon, and Samantha B. Joyce. 2006. “Ramifications of increased salinity in tidal freshwater sediments: geochemistry and microbial pathways of organic matter mineralization. Journal of Geophysical Research, 111: G01009.

- By Alexis Boytim

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