Endogenous clocks have a key role in shaping an organism’s rhythmic life, thereby determining fitness and interactions with other organisms. In the open ocean, pelagic animals like zooplankton perform vertical migrations that actively shape the realized environmental cycles that they experience. As endogenous clocks affect migrations and environmental cycles entrain endogenous clock, this creates a paradoxical chicken-and-egg situation that in this form does not exist in terrestrial habitats.
We want to understand how pelagic clocks do properly function in the unique interplay between their own rhythmicity, migration behavior, and the 3D pelagic environment.
- What mechanistic adaptation ensure proper clock functioning in the pelagic
environment?
- What environmental cues are central for entraining clock rhythmicity?
- What aspects of phenotypic rhythmicity are driven by a clock, and what are direct
responses to the environment?
soeren.haefker@awi.de
+49.(0)471/4831-2360
Dr. Khurshid Bhuiyan
khurshid.bhuiyan@awi.de
+49.(0)471/4831-2360
The planktonic copepod Calanus finmarchicus is an ecological key species in the northern Atlantic food web, with a distribution range from the Gulf of Maine to Svalbard. Like various other pelagic organisms, it performs diel vertical migrations (DVM) that can change depending on environmental conditions. Additionally, the copepod also performs seasonal vertical migrations (SVM), retreating to deeper waters in autumn/winter to enter a resting state (“diapause”).
C. finmarchicus possesses a functional circadian clock with robust clock gene cycling under both lab and field conditions. Further, both respiration and migration rhythms are affected by the clock. Yet, the exact drivers of DVM behavior as well as the mechanisms triggering SVM are so far unknown.
We aim to answer ecologically relevant questions by using integrative approaches that address and connect multiple levels of biological organization.
To disentangle the mechanistic interactions within the copepod's circadian clock, we employ diverse molecular approaches included gene expression, cell culture assays, and in situ stainings. Physiological assays and behavioral experiments provide insight into organismic processes and phenotypic rhythmicity. Further, field investigations are used to integrate our laboratory results into a real-world context.
Rhythms and Clocks in Marine Organisms
NS Häfker, G Andreatta, A Manzotti, A Falciatore, F Raible, K Tessmar-Raible
Annual Review of Marine Science 15, 509-538 (2023) https://doi.org/10.1146/annurev-marine-030422-113038
Animal Behavior Is Central in Shaping the Realized Diel Light Niche
NS Häfker, S Connan-McGinty, L Hobbs, D McKee, JH Cohen, KS Last
Communications Biology 5: 562 (2022) https://doi.org/10.1038/s42003-022-03472-z
Circadian Clock Involvement in Zooplankton Diel Vertical Migration
NS Häfker, B Meyer, KS Last, DW Pond, L Hüppe, M Teschke
Current Biology 27: 2194-201 (2017) https://doi.org/10.1016/j.cub.2017.06.025
Calanus finmarchicus Seasonal Cycle and Diapause in Relation to Gene Expression, Physiology, and Endogenous Clocks
NS Häfker, M Teschke, KS Last, DW Pond, L Hüppe, B Meyer
Limnology and Oceanography 63: 2815-38 (2018) https://doi.org/10.1002/lno.11011
Evidence for oscillating circadian clock genes in the copepod Calanus finmarchicus during the summer solstice in the high Arctic
L Hüppe, L Payton, K Last, D Wilcockson, E Ershova, B Meyer
Biology Letters 16: 20200257 (2020) https://doi.org/10.1098/rsbl.2020.0257
Widely Rhythmic Transcriptome in Calanus finmarchicus during the High Arctic Summer Solstice Period
L Payton, L Hüppe, C Noirot, C Hoede, KS Last, D Wilcockson, E Ershova, S Valière, B Meyer
iScience 24: 101927 (2021) https://doi.org/10.1016/j.isci.2020.101927
Revealing the Profound Influence of Diapause on Gene Expression: Insights from the Annual Transcriptome of the Copepod Calanus finmarchicus
L Payton, KS Last, J Grigor, C Noirot, L Hüppe, DVP Conway, M Dannemeyer, D Wilcockson, B Meyer
Molecular Ecology 33: e17425 (2024) https://doi.org/10.1111/mec.17425
