Figure 2. Changes in biomass (chlorophyll content) of periphyton (top panel), phytoplankton (middle panel) and epipelon (bottom panel) in replicated control (solid lines) and nutrient-spiked (dotted lines) enclosures in the Blind Channel. Vertical solid bars indicate the N+P additions on 20 June and 2 August 1993. Error bars are the standard deviation of six replicate substrata from each of two replicated enclosures.