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Summer Research Project 2017
- Title: Global warming and forest soil microbiomes
- Group Project Leader: Jeffrey Blanchard
- Mentors: Jeffrey Blanchard; William RodrÃguez-Reillo
- Collaborators:
- Project Description:
Earth's climate is warming, and this is causing both biophysical (e.g., albedo) and biogeochemical (e.g., carbon cycle) feedbacks to the climate system. Increased temperature seems to alter soil organic matter (SOM) processing, and if warming accelerates SOM decomposition then carbon (C) stored in soils will transfer to the atmosphere, resulting in a self-reinforcing (positive) feedback to the climate system. Though soil microbes are major drivers of soil C cycling, we lack an understanding of how temperature affects SOM decomposition and CO2 flux. The results from prior experimental warming forest soil studies at Harvard Forest show that higher temperatures increase the flux of CO2 from forest soils into the atmosphere. Warming is also causing a decrease in the soil organic layer and changes in soil microbial community structure. Higher temperatures continue to stimulate CO2 flux despite these substantial changes to the soil.
Our objective in this proposed research is to determine the metabolic pathways differentially regulated in the warming sites by time series analysis of gas flux and microbial community data at the Prospect Hill and Barre Woods long-term warming sites. We will determine what molecular process and taxa are related to the increased CO2 flux and test hypotheses proposed to explain the warming-induced soil organic matter (SOM) decomposition and CO2 flux. The summer 2017 REU project will involve analysis of these time series data sets and conducting related experiments involving laboratory microcosms and DNA/RNA extraction. Some of the questions we are asking include:
1) Are some microbial species declining in abundance as a result of soil warming?
2) How has microbial community structure changed in response to soil warming?
3) What is the underlying mechanism for the observed decrease in temperature-dependent respiration.
This project will involve laboratory-based research at the University of Massachusetts and Harvard Forest, field work at Harvard Forest. Dr. Blanchard will be the primary mentor, meeting with the student on a regular basis to discuss project goals and progress.
The student researcher will be responsible for:
1. assisting in collecting soil cores, laboratory soil microcosms, DNA and RNA extraction from soils and the analyses of soil community genetic data.
2. learning and using statistical software programs (R, python) to analyze results
3. writing a manuscript-style final paper synthesizing background readings/literature and summer results
4. presenting project findings to the research community at the summer symposium
Must have a valid driver license to drive HF vehicles. No specific prior computer or laboratory skills are required...just a willingness to learn about the amazing diversity of microorganisms present in the forest soil.
- Readings:
Metagenomics and Our Microbial Planet. Resources from the National Academy of Sciences. http://dels-old.nas.edu/metagenomics/
Melillo JM, Butler S, Johnson J, Mohan J, Steudler P, Lux H, Burrows E, Bowles F, Smith R, Scott L, Vario C, Hill T, Burton A, Zhou YM, Tang J. Soil warming, carbon-nitrogen interactions, and forest carbon budgets. Proc Natl Acad Sci U S A. 2011 Jun 7;108(23):9508-12.
Pold G, Billings AF, Blanchard JL, Burkhardt DB, Frey SD, Melillo JM, Schnabel J, van Diepen LT, DeAngelis KM (2016) Long-term warming alters carbohydrate degradation potential in temperate forest soils. Appl Environ Microbiol. pii: AEM.02012-16.
DeAngelis KM, Pold G, Topcuoglu BD, van Diepen LTA, Varney R, Blanchard JL, Melillo J, Frey SD (2015) Long-term forest soil warming alters microbial communities in temperate forest soils. Frontiers in Microbiology. 6:104. doi: 10.3389/fmicb.2015.00104
- Research Category: Soil Carbon and Nitrogen Dynamics, Large Experiments and Permanent Plot Studies
