Monthly Archives: May 2010

Tropical Forest Rainfall Manipulation Experiment

Tana Collecting Soils

Tana E. Wood & Whendee L. Silver

Tropical forest soils are a major source of radiatively-active trace gases, including carbon dioxide (CO2) and nitrous oxide (N2O). Climate change is likely to alter soil moisture availability in tropical forests, and consequently the magnitude and temporal pattern of trace gas efflux from these systems (Matson & Vitousek 1990; Davidson et al. 2004; Werner et al. 2006). Currently, quantitative research that definitively investigates the role of soil moisture as a regulator of gas efflux from tropical forest soils is limited (see Davidson et al. 2004; Vasconcelos et al. 2004; Werner et al. 2006). To fully understand how the chemical composition of our atmosphere and climate will change, research examining the processes controlling trace gas emissions from tropical soils is essential.

Building on long-term ecological data at the Luquillo Experimental Forest (LEF), in Puerto Rico, we are conducting a small-scale throughfall exclusion experiment to answer the following questions:

  • What is the role of soil moisture in mediating the efflux of the radiatively-active trace gases carbon dioxide (CO2), nitrous oxide (N2O) and methane (CH4) from the soils of a humid tropical forest?What is the relative contribution of trace gas efflux due to root-rhizophere response to soil moisture variability versus that of heterotrophic bulk soils?
  • What physical and chemical changes that accompany reduced soil moisture affect the efflux of trace gases from tropical soils.

Results from this study will provide critical data for predicting consequences of climate change in tropical regions.


Ariel E. Lugo, Eoin Brodie


Danielle Matthews, Braulio Quintero, Carlos Torrens



NOAA Global and Climate Change Postdoctoral Fellowship, Long-Term Ecological Research (LTER)- Luquillo Experimental Forest, International Institute of Tropical Forestry (IITF), Lawrence Berkeley National Laboratory, University of California, Berkeley

Effects of Rangeland Management on Soil Carbon Sequestration

becca lab

Rangelands represent one of the largest land-use footprints in the world and hold significant potential for employing soil carbon sequestration strategies to help mitigate climate change. California rangelands exhibit a wide range in soil carbon pool sizes. Theses differences are not correlated strongly with precipitation or soil type, indicating that management may play an important role in soil carbon storage or loss. To further explore the relationship between rangeland management and carbon storage, we have established large-scale field manipulations at two working grassland ecosystems: (1) the UC Sierra Foothills Research and Extension Center and (2) the Nicasio Native Grass Ranch. Specifically, we are looking at the short- and long-term effects of organic amendments and subsoiling on soil respiration, net primary productivity, soil carbon fractions, and extracellular enzyme activities. This work is part of a multi-stakeholder collaborative effort to assess the potential for soil carbon sequestration, called the Marin Carbon Project. For more information, see



Silver, W.L., Ryals, R.A., and Eviner, V. Regional patterns in soil carbon pools in California’s annual grassland ecosystems. Journal of Rangeland Management.

Greenhouse Gas Dynamics in Bay Delta Peatlands

cows delta California’s Sacramento-San Joaquin Delta

Peatlands play a significant role in the Earth’s terrestrial carbon (C) cycle, accounting for approximately one-third of the global soil C reservoir. In addition, peatland soils are a significant source of methane (CH4) to the atmosphere, a potent greenhouse gas with 25 times the global warming potential of carbon dioxide (CO2).

We are working in managed peatlands of the Sacramento-San Joaquin Delta of California to understand how methanogens and methanotrophs affect the production and consumption of methane as it diffuses through the soil profile (Silver et al., 1999; Teh et al., 2005). These studies will be supplemented with measurements of soil oxygen and the isotopic content of the methane and CO2. We are also conducting incubation studies to quantify carbon turnover times and sensitivity of CO2 and methane emission rates to temperature and soil moisture.


Dennis Baldocchi, Maggi Kelly

bay delta samplingPostdoctoral Students

Tana Wood, Yit Arn Teh

PhD Students

Wendy Yang

Institutions/Funding Sources

NSF, University of California-Berkeley