The University of Arizona

Research Faculty

Joost van Haren

Assistant Research Professor, Biosphere 2

vanHaren

Area of Expertise:

I am an earth scientist who currently studies soil-plant-atmosphere interactions. I specialize in concentration and stable isotope analysis of greenhouse gases (CH4, CO2, and N2O), soil conditions (physical and chemical), and forest dynamics (tree growth and mortality). I currently serve as lead scientist of B2 rainforest and coordinator for the Amazon-PIRE field course in Brazil.

Research Interests:

My research interests fall within the realm of how biology affects the atmosphere and how this interaction is affected by climate and human perturbations. I have focused on the production of nitrous oxide (N2O) and how this responds to precipitation variability and tree species identity and carbon sequestration. Also, since soil microorganisms are the main producers of N2O, I am working on linking microbial ecology and activity to biogeochemistry. The ultimate goal is to increase our understanding and predictive capability of how microbes affect the atmosphere.

On the ecosystem level, I am interested in the responses of tree species to climate change and soil fertility.

I am developing research programs that address the human role in greenhouse gas emissions and how we can maximize our land-use for both food security and greenhouse gas mediation.

Education:

  • PhD Environmental Science, 2011, University of Arizona, Tucson, AZ
  • MS Geology & Geophysics, 1995, Yale University, New Haven, CT
  • BS Earth Sciences, 1989, Utrecht University, Utrecht, The Netherlands

Current Research Projects:

  • Tropical rainforest drought. Drought is the major climate change threat to the Amazon basin, but we know very little about how tropical forests and individual tree species respond to drought. The B2 research facility provides an unique environment to impose drought and then measure how the whole ecosystem and it’s parts (plants and soils) respond over time. The infrastructure at B2 also allows us to use and test experimental technology before these methods would be deployed in remote tropical locations. We currently are planning to conduct a drought in the B2 rainforest starting late October through December.
  • Influence of light, temperature and water availability on carbon and nutrient cycling in the plant-soil continuum of the tropical rainforest biome: a seedling-scale experiment. We started a five-year potted-seedling experiment in the B2 rainforest. Through this seedling-level the experiment, we aim to gain valuable insight into how light, temperature, and VPD interact and affect carbon and nitrogen cycling both above and below ground in a selection of tropical forest tree species, beginning at the newly-emerged seedling stage. The results of this experiment will add to the growing body of knowledge on how tropical forests will respond to global climate change, but most importantly will fill in critical gaps by isolating variables such as temperature and moisture that have proven difficult to independently characterize in recent experimentation.
  • Linking tropical N2O emissions to ecosystem properties. This project is a continuation of my thesis research, during which I linked soil N2O fluxes to tree species identity (in diverse tropical forests), tree growth, and overall forest growth. My previous work was conducted within the central Amazon basin, and currently I am expanding that work to the western Amazon basin where high forest growth rates suggest that soil N2O fluxes are high. I am also planning to use the gained knowledge on tree species identity to assess the generality of that information and whether it can be used for flux predictions.
  • Development of automated, no-impact soil chambers. Most commercially available and custom designed automated soil chambers cut through the soil surface to provide a seal between soil and chamber. This design not only cuts the soil, but also shallow roots. Since plants have a strong influence on soil microbes, root cutting can disturb this link and lead to erroneous soil flux measurements (Heinemeyer et al. 2011, European J. Soil Sci.). Chamber designs that do not cut the soil often have problems sealing the soil surface, which will be overcome by a 3cm wide 1cm thick closed cell foam seal on the bottom of the chamber.

Publications:

Publications (in Prep.)

  • van Haren J, Oliveira RC, Keller M, Saleska S (Submitted) Tree Species effects on soil CO2 and N2O production in a tropical monoculture and diverse forest. Biotropica.
  • van Haren J, Saleska S, Oliveira RC, Li C, Frolking, S, Varner R, Keller M, Crill P (To Be submitted Fall 2011) Forest growth predicts tropical soil N2O fluxes. PNAS.
  • van Haren J, Varner R, Oliveira RC, Li C, Frolking S, Keller M, Saleska S (To be submitted Fall 2011) Spatial and temporal variability of soil CO2 and N2O fluxes in a clay-rich east-central Amazonian forest. Global Change Biology.
  • van Haren J, Yamagishi H, Yoshida N (To be submitted Fall 2011) Large impact of N2O consumption on soil N2O fluxes: evidence from stable isotope and isotopomer analysis. JGR-Biogeosciences.

Teaching:

  • Soil development and trace gas emission components of the NSF Amazon-PIRE funded course Ecology and Biogeochemistry of the Amazon (ECOL 495T/596T; 2008-current)
  • Guest lecture on soil development and nutrient dynamics in Tropical Ecology and Biogeochemistry (ECOL 596L; fall 2010)

Personnel:

  • Neill Prohaska, Graduate Research Assistant
  • Steve Bissel, electronics technician

Quick Links

Contact Information:
520.838.6165
jvanhare@email.
arizona.edu
The University of Arizona
Biosphere 2
PO Box 8746
Tucson, AZ 85738