Publication Date:
2024-05-13
Description:
The copepod Calanus finmarchicus plays a crucial role in the north Atlantic food web. Its seasonal life cycle
involves reproduction and development in surface waters before overwintering in diapause at depth. Although
diapause has been studied for more than a century, the factors responsible for the initiation and termination of
it are still unclear. Endogenous clocks have been identified as potent tools for photoperiod measurement and
seasonal rhythmicity in many terrestrial species, but knowledge of these remains scarce in the marine realm.
Focusing on the dominant CV copepodid stage, we sampled a population of C. finmarchicus from a Scottish sea
loch to characterize population dynamics, several physiological parameters, and diel and seasonal expression
rhythms of 35 genes representing different metabolic pathways, including the circadian clock machinery. This
generated a detailed overview of the seasonal cycle of C. finmarchicus including the most extensive field dataset
on circadian clock gene expression in a marine species to date. Gene expression patterns revealed distinct gene
clusters upregulated at different phases of the copepod’s seasonal cycle. While diel clock cycling was restricted
to the active spring/summer phase, many clock genes exhibited the highest expression during diapause. Our
results provide new insights into diapause on physiological and genetic levels. We suggest that photoperiod, in
interaction with internal and external factors (lipid content, temperature, food availability) and the endogenous
clock mechanism, plays an important role in the timing of diapause in C. finmarchicus.
Repository Name:
EPIC Alfred Wegener Institut
Type:
Article
,
isiRev
Format:
application/pdf
