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Indiana University Bloomington

Department of Biology

Faculty & Research

Faculty Profile

Richard Phillips

Photo of Richard Phillips
Research Images
Research photo by Richard Phillips

Measuring CO2 flux from soil in a sugar maple stand, NY.

Research photo by Richard Phillips

Pulse labeling pine seedlings with 11CO2.

Research photo by Richard Phillips

Duke Forest FACE site, NC.

Research photo by Richard Phillips

Mycorrhizal tip on loblolly pine root.

Associate Professor of Biology, Director of Research (RTP)

IU Affiliations
Center for Research in Environmental Sciences
IU Research & Teaching Preserve
School of Public and Environmental Affairs

Contact Information
By telephone: 812-856-0593/6-1563(lab)
JH 247A/JH 245

Phillips Lab website

Evolution, Ecology & Behavior
Research Area

Postdoctoral Fellow, Duke University, 2005-2008
Ph.D., Cornell University, 2000-2005
M.S., SUNY College of Environmental Science and Forestry, 1996-1998

Research Description

My research broadly seeks to quantify and better understand how plants and soil microbes influence energy flow and nutrient cycling in terrestrial ecosystems in the wake of human-accelerated environmental change.  Of particular interest is the degree to which plant-microbial interactions in soils influence feedbacks to regional and global change through their effects on ecosystem carbon storage and nitrogen and phosphorus retention. I use a complimentary suite of approaches that integrate field observations with novel techniques (e.g. stable and radioactive isotopes) and controlled environmental systems (e.g. growth chambers, FACE sites) to address questions that intersect plant physiological ecology and soil microbial ecology in an ecosystem context. 

There are three broad themes to my research:

Coupling of plant and microbial productivity.  In terrestrial ecosystems, plants and soil microbes are highly interdependent as plants rely on microbes to transform nutrients to an “available” form, and microbes rely on plants to provide reduced C for metabolism.  Despite the apparent simplicity of the interaction, there are significant gaps in our understanding of factors that mediate the coupling of carbon and nutrient cycles.  It is often assumed leaf litter quality controls nutrients availability in soils.  However, plants also release appreciable amounts of carbon from roots, and these inputs may have a disproportionate effect on nutrient availability in the zone of soil adjacent to roots (i.e. the rhizosphere).  A theme of my research is to better understand the role of roots in influencing the coupling of plant and microbial productivity through their effects on nutrient cycling.  

Species effects on nutrient cycling.  A fundamental question in ecology is the role of species in influencing ecosystem processes.  This question has become increasingly important given the loss of species, increases in non-indigenous species, and predicted shifts in the distribution and abundance of species owing to global climate change.  In forests, most research has focused on tree species effects on ecosystem processes through differences in foliar traits, with little consideration of species differences in nutrient acquisition strategies.  My research seeks to improve upon our understanding of species effects on nutrient cycling by examining differences in nutrient acquisition strategies among tree species, with a focus on root-induced alterations of rhizosphere microbes and their impacts on carbon and nutrient economies.

Plant-soil-microbial feedbacks to global change.  Interactions between plants, soils, and microbes mediate the flow of energy and nutrients through ecosystems with the potential to feed-back to primary production through effects on carbon sequestration in biomass and soils.  This has led to speculation that terrestrial ecosystems – particularly forests – may mitigate elevated levels of atmospheric CO2 through increases in productivity.  However, the persistence of forests as carbon sinks over the long-term will likely depend on the degree to which trees increase access to soil resources such as water and nutrients.  A broad theme of my research is to quantify the degree to which plant-soil-microbial interactions mediate ecosystem-responses to global environmental changes such as drought, warming, N deposition and rising atmospheric CO2.

Select Publications
Finzi, A.F., Abramoff, R.Z., Spiller, K.S., Brzostek, E.B., Darby, A.B., Kramer, M.A., and R.P. Phillips. 2015. Rhizosphere processes are quantitatively important components of terrestrial carbon and nutrient cycles. Global Change Biology. DOI: 10.1111/gcb.12816
Midgley M.G., Brzostek, E.R. and R.P. Phillips. In Press. Decay rates of high-quality AM leaf litters are more sensitive to soil effects than low-quality ECM litters. Journal of Ecology
Roman, D.T., Novick, K.A., Brzostek, E.R., Dragoni, D., Rahman, F. and R.P. Phillips. In Press. The role of isohydric and anisohydric species in determining ecosystem-scale response to severe drought. Oecologia; DOI 10.1007/s00442-015-3380-9
Brzostek, E.R., Dragoni, D., Brown, Z.A., and R.P. Phillips. 2015. Mycorrhizal type determines the magnitude and direction of root-induced changes in decomposition in a temperate forest. New Phytologist. DOI: 10.1111/nph.13303
Yin, H., Wheeler, E., and R.P. Phillips. 2014. Root-induced changes in nutrient cycling in forests depend on mycorrhizal type. Soil Biology & Biochemistry. 78: 213-221
Midgley M.G. and R.P. Phillips. 2014. Mycorrhizal associations mediate nitrate leaching responses to N deposition: a meta-analysis. Biogeochemistry. 117 (2-3): 241-253
Sulman, B.N., Phillips, R.P, Oishi, C., Shevliakova, E., and S.W. Pacala. 2014. Microbe-driven turnover offsets mineral-mediated storage of soil carbon under elevated CO2. Nature Climate Change. 4:1099 – 1102
Brzostek, E.R., Dragoni, D., Schmid, H.P., Rahman, A.F., Sims, D., Wayson, C.A., Johnson, D.J., and R.P. Phillips. 2014. Chronic water stress reduces tree growth and the carbon sink of deciduous hardwood forests. Global Change Biology; 20(8):2531–2539
Meier, I.C., Pritchard, S., Brzostek, E.R., M. L. McCormack, and R.P. Phillips. 2014. Rhizosphere and hyphosphere differ in their impacts on carbon and nitrogen cycling in forests exposed to elevated CO2. New Phytologist. DOI: 10.1111/nph.13122  
Brzostek, E.B., J.B. Fisher and R.P. Phillips. 2014. Modeling the carbon cost of plant nitrogen acquisition: mycorrhizal trade-offs and multi-path resistance uptake improve predictions of retranslocation. JGR - Biogeosciences. DOI: 10.1002/2014JG002660
Phillips, R.P., Midgley, M.G. and E. Brzostek. 2013. The mycorrhizal-associated nutrient economy: A new framework for predicting carbon-nutrient couplings in forests. New Phytologist, 199:41-51,
Phillips, R.P., Meier, I.C., Bernhardt, E.S., Grandy A.S. Wickings, K, and A.F. Finzi. 2012. Roots and fungi accelerate carbon and nitrogen cycling in forests exposed to elevated CO2. Ecology Letters. 15: 1042-1049
Phillips, R.P., A.F. Finzi and E.S. Bernhardt. 2011. Enhanced root exudation induces microbial feedbacks to N cycling in a pine forest under long-term CO2 fumigation. Ecology Letters. 14: 187–194

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