Figure 1.

(A) A close-up view of one experimental chamber unit on 8 December 2006, with an experimental mesocosm (with the central light level (i.e., PAR) sensor) monitored by both an opaque and transparent (Perspex) chamber. The black membrane prevented soil splashing and two “harvest collars” are seen in the background. Tilting of the collar limited collar rim shading and improved drainage. (B) Climatic conditions during the experiment showing hourly temperatures measured inside the chamber (Cham Temp), soil surface (Surf Temp) and in 2 and 5 cm soil depth (Soil Temp 2 and 5 cm, respectively) and mean hourly ambient PAR levels (PAR; delayed monitoring start).