JOURNAL OF PLANKTON RESEARCH
VOLUME 32 j
NUMBER 4 j
PAGES 441–456 j 2010
Fig. 3. The distribution pattern of the animals in the experimental chamber: (a) Polychaeta larvae, May; (b) non-mature copepodites of Oithona similis, August; (c) naupliar and young (CI-CIII) copepodite stages of emora longicornis, early June; (d) CIV-CV copepodites of T. longicornis, October; (e) naupliar stages of Calanus glacialis, May; (f) CIV copepodites of Netridia longa, October; (g) Pseudocalanus minutus naupliar stages, May; (h) P. minutus CI-CII copepodite stages, early June; (i) P. minutus CIII copepodite stages, early June. Vertical bars represent the standard deviation (s, P , 0.05).
48 h of acclimation both in total darkness and in light in August. Individuals of the last generation (October) also had positive phototaxis, but their behavioral responses to the RY light were not significantly different after being kept under various acclimation environ- ments. In contrast to Acartia, immature copepods (August) and mature females (October) of C. hamatus dis- played pronounced negative phototaxis after 48 h acclimation in different light conditions (Table I). At the
end of September to the beginning of October, imma- ture individuals of this species were characterized by positive phototaxis, but the effects of the duration and light conditions of acclimation were not significant. emora longicornis also had a different pattern of response. During the polar day period (May–June) naupliar and immature copepods had strong positive phototaxis (Fig. 3c), which increased significantly in agreement suggest with the acclimation duration. Maintaining the
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