KBS undergraduate summer researcher Aleah Dungee is majoring in Biology at Norfolk State University. She wrote about her Research Experience for Undergraduates experience working with Di Liang, an LTER graduate student in Phil Robertson’s lab. Aleah was funded by an NSF REU site award to the Kellogg Biological Station.
This summer as a participant in the Research Experience for Undergraduates program at the Kellogg Biological Station, I researched the relative contributions of ammonia oxidizing archaea (AOA) and ammonia oxidizing bacteria (AOB) to nitrification on different land use types. I worked in Dr. Phil Robertson’s lab with PhD student Di Liang. Here’s a little background information about my research before we dive into my experience I had with the forest. Soil nitrification is a biological process that converts ammonia to nitrate. It is known that AOA and AOB are able to nitrify, but it is unclear how much they contribute to this process individually. To answer this question, we conducted an experiment at the Kellogg Biological Station (KBS) Long Term Ecological Research (LTER) site to determine how AOA and AOB contribute to soil nitrification. Soil samples were taken from seven different treatments including T1 (conventional wheat), T4 (biologically-based wheat with cover crop), T5 (poplar), T7 (early successional community), T7 fertilized subplots, DF (deciduous forest), and DF fertilized subplots.
In LTER, there is a plot called T5 that contains poplar trees. This plot resembles a forest. When I buried my bottles in T5, I normally didn’t have an issue, but one day I saw a strange brown animal standing next to the spot where I had buried my bottles. My heart literally dropped into the pit of my stomach. I tried making little noises to get the animal to run along, but this strange creature would NOT budge. I do not know if you would call this crazy, but I got a little closer to the animal, as if I knew it would not bite. To my surprise, it ran off. It was then that I had realized this animal was not a strange creature, but a fawn (baby deer).
When I finally took a deep breath and lowered my heartrate, I proceeded to the spot where I had buried my bottles. To my amazement, they were not buried, someone or SOMETHING had dug them out and took them out of the bag. Take a look:
I do not know who or what could have done this. I knew if this happened here in T5 it could also happen in the deciduous forest, but WORSE. Once we removed all bottles from all of my experimental treatments, we proceeded to the deciduous forest…
There are three replicates of the deciduous forest: DF1 (biggest), DF2 (medium-sized), DF3 (smallest). DF1 and DF2 had a long trail that lead us to the place where we buried our bottles, but DF3 had only a short pathway. In DF3, we buried our bottles close to the entrance of the forest where the soil was nice and soft (almost like the Muskegon beach sand). Once we got there, we noticed an empty hole. We were stunned. ALL SIX OF OUR BOTTLES WERE MISSING. After searching the area, we found our bottles, but they looked as if an animal was trying to make our bottles their play toy. I came to the conclusion that it must have been a coyote. Fast forwarding to the next week, we went to dig our bottles out again, and long and behold…our bottles weren’t missing once, but twice.
“Let’s get a camera,” my mentor Di Lang suggested. So we got a camera and put it where our bottles were buried. The following week, our bottles were missing AGAIN, so we looked to see what the camera caught. ABSOLUTELY NOTHING!!! I was so depressed that the bottle-snatcher was not caught on camera, but we knew the animal was taunting us. Even though our bottles were not in their original place, we were always able to find them not too far from the site.
After the conclusion of my experiment, we obtained really interesting results. By sampling seven different ecosystems, we were able to obtain CO2 emission rates, field net nitrification rates, and soil pH. CO2 emission rates in T7 fertilized subplots are significantly higher than T1, T4 and T5. This might be because there is more organic carbon that accumulated in T7 fertilized subplots. T4 and DF had the highest field net nitrification rates. This reflects the constant supply of organic matter from the cover crop in T4 and plant detritus in DF. Heterotrophs dominated nitrification in T1 and T4; however, in DF there is was no evidence of heterotrophic nitrification. The pH of the fertilized subplots was significantly lower than their non-fertilized treatments (as shown in T7 and DF). This was expected because fertilizer facilitates nitrification, which causes soil acidification. Except DF and DF fertilized subplots, heterotrophic nitrification contributed to at least 30% of the total nitrification. In T5, T7 and T7 fertilized subplots, autotrophic nitrification was responsible for at least 70% of nitrification.
All in all, working in the deciduous forest was a great, scary, and eerie feeling. I was always looking over my shoulder, listening out for strange noises. On the other hand, the forest was a beautiful place, especially to escape from the treacherous summer sun. I have learned a vast amount of information over the summer working with my mentor Di Lang.
Nothing will compare to my experience at the W.K. Kellogg Biological Station or the experience of wild animals STEALING MY BOTTLES!