The effects of Cu on the adenylate energy charge of open ocean phytoplankton

The effects of short-term, acute Cu exposure (6 h) on the adenylateenergy charge (EC_A) of open-ocean phytoplankton populations(northeastern equatorial Pacific) were investigated. Energycharge remained at {small tilde}0.77 over the range of Cu additions(0.025 – 5.µg l^–1), even though ¹⁴C uptakeand total adenylate levels (ATP + ADP + AMP) were reduced byas much as 60%. These findings suggest that EC_A alone is nota sensitive indicator of acute sublethal metal effects on phytoplankton. ¹This research was supported by the NSF Biological OceanographyProgram grant #OCE 81-17286.