A first estimation of the role of penguin guano on copper cycling and organic speciation in Antarctic coastal waters.

Cu is a vital micronutrient, but free Cu ions (Cu) in seawater, even at subnanomolar concentrations, can impede phytoplankton growth. Natural Cu complexation with organic ligands regulates Cu acquisition and, in most instances, reduces Cu concentrations below toxic thresholds. Along the Antarctic coast, the sources and sinks of Cu and its associated ligands remain poorly defined.