Publication Date:
2017-01-20
Description:
The marine copepod Calanus finmarchicus is an important key species in the Northern
Atlantic due to his abundance and his position in the food web. It performs diel vertical
migration (DVM), staying in deeper water layers during the day and ascending to the
surface in the night. The exact trigger for the DVM is not known yet, but light seems to
have an important influence on the position of C. finmarchicus. Some studies suggest an
involvement of an endogenous rhythm, which controls the vertical position of
C. finmarchicus throughout the day. In this work the DVM and respiration rate of
C. finmarchicus were examined under natural simulated light conditions to identify
possible circadian rhythms. Therefore, two laboratory experiments were performed with
the CV-stage of C. finmarchicus under light/dark (LD) and constant darkness (DD)
conditions. The position of C. finmarchicus in the DVM experiment showed a clear diurnal
rhythm, with significant differences between day and night. The rhythm persisted in
weaker form during constant darkness, indicating that an endogenous circadian clock is
involved in the DVM. The results from the respiration experiment supported the
assumption, revealing a rhythmicity in the oxygen uptake that also persisted under
constant darkness. The light seemed to have in both experiments the role of a Zeitgeber
that synchronises the circadian clock. For a final identification of the assumed clock a
genetic analysis is necessary. However the experiments showed evidence that the DVM
and the metabolic activity of C. finmarchicus are controlled by a circadian clock.
Repository Name:
EPIC Alfred Wegener Institut
Type:
Thesis
,
notRev
Format:
application/pdf
