The SOSC value in P. abies-exposed individuals did not significantly
differ from the control with the underlying mechanism
remaining obscure. However, three exposures caused an oxidative
stress in the water fleas, which could be facilitated by two mechanisms:
external production of ROS from irradiated leachates (Zepp
et al., 1977; Cooper and Zika, 1983) or, after internalization of the
leachates via food or epithelia, internal activation of oxygen (=ROS
production). These mechanisms are not mutually exclusive, but a
comparison of both pathways in a cyanobacterium by Sun et al.
(2005, 2006) emphasized the dominance of the internal over the
external pathway. Most likely, this applies also to exposed Moina.