Publication Date:
2024-05-13
Description:
Biological clocks are a ubiquitous ancient and adaptive
mechanism enabling organisms to anticipate
environmental cycles and to regulate behavioral and
physiological processes accordingly [1]. Although
terrestrial circadian clocks are well understood,
knowledge of clocks in marine organisms is still
very limited [2–5]. This is particularly true for abundant
species displaying large-scale rhythms like diel
vertical migration (DVM) that contribute significantly
to shaping their respective ecosystems [6]. Here
we describe exogenous cycles and endogenous
rhythms associated with DVM of the ecologically
important and highly abundant planktic copepod Calanus
finmarchicus. In the laboratory, C. finmarchicus
shows circadian rhythms of DVM, metabolism, and
most core circadian clock genes (clock, period1,
period2, timeless, cryptochrome2, and clockwork
orange). Most of these genes also cycle in animals
assessed in the wild, though expression is less rhythmic
at depth (50–140 m) relative to shallow-caught
animals (0–50 m). Further, peak expressions of clock
genes generally occurred at either sunset or sunrise,
coinciding with peak migration times. Including one
of the first field investigations of clock genes in a marine
species [5, 7], this study couples clock gene measurements
with laboratory and field data on DVM.
While the mechanistic connection remains elusive,
our results imply a high degree of causality between
clock gene expression and one of the planet’s largest
daily migrations of biomass. We thus suggest that
circadian clocks increase zooplankton fitness by
optimizing the temporal trade-off between feeding
and predator avoidance, especially when environmental
drivers are weak or absent [8].
Repository Name:
EPIC Alfred Wegener Institut
Type:
Article
,
isiRev
Format:
application/pdf
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