Meet some of the amazing future scientists who have worked with me at the University of Notre Dame Environmental Research Center and the Kellogg Biological Station. Learn more about their experiences and the research they conducted on freshwater lakes and on marginal land Switchgrass soils. These students have not only significantly contributed to my research projects, but they have also taught me how to become a better science educator.
Kathryn Bloodworth
For the last eleven weeks I have had the privilege of working at the Kellogg Biological Station (KBS) alongside Dr. William West as part of the Research Experience for Undergraduate (REU) program. Although I am an REU, I am also a SEEDS Partnership for Undergraduate Research (SPUR) Fellow. SEEDS, an program run through the Ecological Society of America has given me the incredible opportunity to work at the Kellogg Biological Station this summer and travel to the Ecological Society of America’s annual meeting next summer. I took this summer (2016) as an opportunity to explore the country and enjoy new experiences. When I first started to work at KBS, I was eager to begin a research project that was far above anything I have learned or experienced before. Although this project required a lot of preliminary work and many long days of learning concepts and understanding ideas, it has been one of the most rewarding experiences of my life. This summer, my research set out to understand more about the affects that organic carbon quantity and quality have on the ratio of nitrous oxide to nitrogen gas that is released from the microbial community of marginal land Switchgrass Soils at KBS . Since climate change is impacted heavily by greenhouse gas emissions, much of which comes from the burning of fossi fules, biofuel crops are currently being evaluated as potential alternative energy sources. Switchgrass is considered an ideal candidate: consequently it is crucial to assess all aspects of its greenhouse gas budget and its potential as a sustainable biofuel crop. Although my summer research experience is only the beginning of a much larger project, I am excited to have contributed the work that I did and to be able to follow through with the project in the following months. During this project I learned a lot about the research process and how time consuming and difficult it can be to get the methodologies correct. I also learned how rewarding it is to receive results and to be able to interpret the data. This summer has also given me the opportunity to learn a variety of lab techniques and what it means to be a researcher in a lab setting with many colleagues. Through a summer of immense learning and incredible new experiences, I also made friends that I will have for a lifetime. We have spent countless hours together, whether it be doing work, helping each other with projects, making dinners, or camping. The people that I have met during my time at The Kellogg Biological Station have becoming family to me. The summer Research Experience for Undergraduate Program at the Kellogg Biological Station has been overwhelming amazing. The staff is unbelievable, and consistently goes out of their way to help you with what they can. Being a SPUR Fellow and REU is one that I would suggest for anyone. It is a great opportunity to learn more about the research process and our environment. These past eleven weeks have been some of the best of my life, and it has been an absolutely wonderful summer, to say the least.
Elyssa Schwendy
Methane (CH4, is a potent greehouse gas that has a significant effect on climate change, yet there are few reliable estimates of current emission rates. Freshwater ecosystems, and in particular northern lakes, are thought to contribute meaningfully to atmospheric levels of CH4, but the factors that control emission rates are not well known. This experiment studied five freshwater lakes over the course of ten weeks to determine the amount of CH4 being emitted by two of the major emission pathways—ebullition and diffusion—in an attempt to find meaningful relationships between ebullition rates and other factors. My work demonstrated that sediment temperature relates to ebullition, but that surface temperature, average depth, surface area, and production do not. Current estimates of the relative amounts of CH4 emitted by ebullition and diffusion were disproved, with our results suggesting that ebullition is not necessarily the dominant pathway for CH4 emissions in all lakes. Evidence that littoral sites display significantly higher ebullition rates compared to pelagic sites was supported by the data collected on the five lakes used for the study. Overall, the study suggests that factors that are currently accepted as indicators of ebullition rates may not be applicable for all lakes in all regions. These factors will have to be reevaluated in order to determine the effect freshwater lakes have on global atmospheric CH4 concentrations.
Mike Kipp
Freshwater inland lakes are a significant source of atmospheric methane (CH4), and despite covering less than 1% of the earth’s surface, lakes emit more CH4 than the ocean. With freshwater lakes missing from many atmospheric circulation models, there is a need to quantify their potential climate impact. A positive feedback in the global climate has been observed, with CH4 emissions from lakes increasing as lakes warm. The mechanism involves both an increased production of CH4 in the littoral sediments, and increased diffusive efflux from warm surface water. Methane cycles in lakes were characterized over the course of a summer, and drivers of emissions were determined. Methane production, CH4 storage, and lake surface area to volume ratio were determined to be reliable predictors of CH4 emissions. Additionally, a strong correlation exists between lake productivity and emissions. This suggests that eutrophication may be an amplifier of existing global change mechanisms. My findings have implications for both existing lakes in temperate and boreal zones, as well as newly forming glacial lakes and wetlands at higher latitudes.
Scott Baker
Methane (CH4) is most potent greenhouse gas, approximately 23x more effective at trapping heat in the atmosphere than carbon dioxide (CO2), on a per molar basis. Accordingly, increased human activity may be driving observed increases in atmospheric CH4. With the human population increasing at an unprecedented rate, the demand for food and fuel is correspondingly increasing. Nutrient additions to crops is a standard practice to promote maximum crop yields. However, increased fertilizer runoff into lakes may be increasing phytoplankton blooms (a potential substrate for microbial mediated CH4 production) and may be reducing the ability of methane oxidizing bacteria (methanotrophs) to consume diffusing CH4. My work involved examining whether methanotrophs have the potential to respond to increased concentrations of CH4 in the water column of lakes. My work demonstrated that methanotrophs respond to higher concentrations of CH4 diffusing through the water column and may potentially mitigate the effects of increased CH4 production in eutrophic lakes.
Shayna McCarthy
Freshwater lakes are subtly dynamic systems continuously managing fluxes while maintaining a seemingly constant physical state. Breakdown of organic matter is facilitated by nutrient cycling at different scales within a lake, and trophic status may play an important role in carbon cycling in freshwater lakes. Ultimately, sediment microbial communities are responsible for the breakdown of substrates into simpler compounds and greenhouse gases (carbon dioxide (CO2) and methane (CH4)). Our previous research has specifically pinpointed phytoplankton as an important labile substrate for methanogenesis (CH4 production) and sediment amended with additionally phytoplankton biomass produced greater quantities of CH4. However, it was unclear whether the quantity, quality, taxonomic affiliation of phytoplankton biomass plays a more important role in increasing sediment methanogenesis. Sediment from five lakes along a trophic gradient, was individually enriched with eukaryotic and cyanobacteria, of different lipid content our work aimed to determine whether total carbon, or specific macromolecular phytoplankton composition influenced sediment methanogenesis from freshwater lakes. Our work demonstrated that phytoplankton taxonomic affiliation was not important in enhancing sediment methanognenesis, but phytoplankton lipid content is a labile carbon source for methanogenesis (West et al. 2015).