Natural Resource Ecology Laboratory

Jenny Rocca (PhD Student)

Jenny RoccaJennifer comes from the University of Texas, where she earned her Masters in Plant Biology in 2010. She started at CSU in 2011, where she now studies the impacts of plant chemistry on belowground function.

Research

PHACE Leaf Chemistry impacts on Soil Function

Soils contain many microbes, which are responsible for the majority of organic breakdown in terrestrial ecosystems. We know a lot about how abiotic factors influence soil microbial function, but the role of water-soluble leaf chemistry in impacting soil microbial function is still generally unknown. Broadly, my research interests addresses the impacts of plant leaf chemistry on belowground soil function. Specifically, I am investigating the consequences of the altered chemistry of water-soluble compounds on soil microbial activity.

In the context of forecasted climate change, I am addressing the indirect impacts of altered climate on belowground activity, as driven by potential shifts in plant community and leaf chemistry in response to the altered environmental conditions. Currently, these questions are being addressed at the PHACE experimental grassland in southern Wyoming, where I am quantifying the effects of the long-term abiotic treatments, including elevated CO2 and temperature, on changes in plant species composition as well as within species plant chemistry and subsequent shift in the suite of compounds entering the soil profile. The indirect influence of altered plant chemistry, in response to elevated CO2 and warming, may be more influential than the direct impacts of these environmental conditions on belowground processes.Research description of primary project.

Meta Analysis: Do Gene Abundances Predict Rates of Corresponding Function

For any enzyme-catalyzed reaction to occur in soil, the presence of the corresponding functional gene and mRNA transcript are pre-requisites. Thus, it is reasonable to assume that the abundance of a functional gene, and better yet, a gene transcript, should correlate to the rate of the resultant function. Based on this underlying assumption, many studies quantify functional genes and transcripts with quantitative PCR. However, factors such as multiple transcriptional and translational events, as well as the transience of nucleic acids or the resultant product, may obscure this relationship. Additionally, certain processes, like denitrification, require the sequential activity of multiple enzymes to produce the final reaction product. DNA molecules may be more appropriate indicators of functional potential rather than instantaneous process rates and may be an integrated index of rates over longer time periods. Transcripts should correlate more closely to instantaneous process rates with their faster turnover rates, but the susceptibility of RNA to degradation also hinders precise quantification. Although fundamental biological theory predicts a close relationship between gene abundance and function, there are many reasons why this relationship could be concealed when linking gene abundance to process rates. We conducted a meta-analysis to address the validity of these assumptions. Is functional gene abundance correlated to rates of corresponding processes? Can gene or transcript quantities be used to infer differences in process rates between distinct habitats?

CV

UVBKonza Biological Field Station

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Matthew David Wallenstein, PhD

Natural Resource Ecology Lab, B258
Colorado State University
1499 Campus Delivery
Fort Collins CO, 80523-1499
(970) 491 - 1623