Elongated chambers for field studies across atmospheric CO2 gradients

Authors

H. B. Johnson, Grassland, Soil and Water Research Laboratory
H. W. Polley, USDA-ARS Grassland, Soil and Water Research LaboratoryFollow
R. P. Whitis, USDA-ARS Grassland, Soil and Water Research Laboratory

Date of this Version

2000

Comments

Published in Functional Ecology (2000) 14, 388–396.

Abstract

We describe a field facility that controls CO₂ along continuous gradients from superambient to subambient concentrations. The facility consists of two transparent, tunnel-shaped chambers, each 1-m wide and tall and 60-m long. Pure CO₂ is injected into one chamber during daylight to initiate a superambient CO₂ gradient (550–350 µmol mol^–1). Ambient air is introduced to the second chamber to initiate a subambient CO₂ gradient (350–200 µmol mol^–1). CO₂ concentrations at night are regulated at 150 µmol mol^–1 above daytime values along each gradient. The CO₂ gradients are maintained by varying the rate and direction (day/night) of air flow.