UV-LIGHT AND VERTICAL-DISTRIBUTION OF THE MARINE PLANKTONIC COPEPOD ACARTIA-HUDSONICA PINHEY

Of the many hypotheses put forth to explain the possible adaptive value of daytime residence in subsurface waters and diel vertical migration behavior of Zooplankton, avoidance of potentially harmful UV radiation has only recently been proposed. We undertook a manipulative field experiment to test the effect of UV-B (290-315 nm) solar radiation on the daytime vertical distribution of the marine planktonic copepod Acartia hudsonica Pinhey. Since no statistically significant difference in the daytime depth distributions of adult A. hudsonica in control and UV-B-filtered treatments was found, we conclude that some other factor(s) must determine the daytime vertical distribution of this copepod. © 1990.