A Versatile Sun‐lit Controlled‐Environment Facility for Studying Plant and Soil Processes

Abstract

A new environmental‐tracking, sun‐lit controlled‐environment facility (terracosm) that can control and manipulate climatic and edaphic factors while maintaining natural environmental variability was developed to study the effects of environmental stresses on a model ecosystem (i.e., plant and soil processes). An analysis of terracosm performance data indicates that the terracosms simulated natural seasonal and diurnal changes in atmospheric CO2, air and soil temperatures, vapor pressure deficit (VPD), and soil moisture. The terracosm performance data indicate that between 92 and 100% of the hourly CO2 concentrations are within ±50 µmol mol−1 of the target concentrations for both ambient and elevated treatments (1 Nov. 1993 through 30 Nov. 1994). Air temperatures are within 2°C of the target temperature between 85 and 100% of the hours for both ambient and elevated temperature treatments. The VPD was approximately the same (0.09 kPa difference between treatments) in the ambient and elevated temperature treatments. Distributed process control was implemented to minimize downtime. Terracosm downtime, periods when terracosm environmental conditions could not be reliably controlled, varied between 2.4 and 2.8% of all hours, and was equally distributed between biological sampling and equipment problems.

Morphotype community structure of ectomycorrhizas on Douglas fir ( Pseudotsuga menziesii Mirb. Franco) seedlings grown under elevated atmospheric CO 2 and temperature

“…Each chamber has a 1×2 m footprint (2 m 2 ) and is one component of an environment-tracking, sunlit, controlled-environment facility that links atmospheric, plant, and soil processes (Tingey et al 1996). The facility simulates natural seasonal and diurnal changes in atmospheric CO 2 , air and soil temperatures, vapor pressure deficit (VPD), and soil moisture.…”

“…Using an acceptance criterion of less than ±2°C, 85 and 100% of all monthly hours fell within nominal conditions for ambient and elevated treatments, respectively. See Tingey et al (1996) for a more detailed analysis of the performance of the facility.…”

“…This bottleneck will accentuate any previous changes in community composition and some time could elapse before the original level of diversity is reestablished. While our GCC experiment was designed to make an integrated, aboveground and belowground analysis of a coniferous seedling-native soil system (Tingey et al 1996), the experiment was suited to studying changes in richness and diversity of the ECM fungal community because we could evaluate the extent of changes in the community while monitoring numerous above-and belowground ecophysiological responses. Here we present findings on the community structure of ECM morphotypes using gross morphological traits to categorize the tips.…”

A method for estimating carbon dioxide leakage rates in controlled-environment chambers using nitrous oxide

“…A total of 18 outdoor chambers are available at this facility and are of two types, referred to here as either 'Daylit' (six chambers) and or Soil-Plant-Atmosphere-Research (SPAR, 12 chambers) chambers. This facility is comparable in design and operation to similar experimental systems at the University of Florida (Pickering et al, 1994), Corvallis, OR (Tingey et al, 1996), and Mississippi State University (Reddy et al, 2001).…”

Final Report for Effect of Asymmetric Versus Symmetric Warming on Grassland Mesocosms

“…The WED mesocosm facilities provided careful monitoring and control of both atmospheric and soil conditions for study of effects of the environment on vegetation and associated soil ecosystem (Tingey et al, 1996). Atmosphere factors monitored and controlled included temperature, carbon dioxide concentration and relative humidity.…”