Evidence of separate influence of moon and sun on light synchronization of mussel's daily rhythm during the polar night

Damien Tran; Hector Andrade; Lionel Camus; Peter Leopold; Carl Ballantine; Jørgen Berge; Guillaume Durier; Mohamedou Sow; Pierre Ciret

doi:10.1016/j.isci.2023.106168

Evidence of separate influence of moon and sun on light synchronization of mussel's daily rhythm during the polar night

iScience. 2023 Feb 9;26(3):106168. doi: 10.1016/j.isci.2023.106168. eCollection 2023 Mar 17.

Authors

Damien Tran^{1

2}, Hector Andrade³, Lionel Camus⁴, Peter Leopold⁵, Carl Ballantine⁴, Jørgen Berge^{5

6}, Guillaume Durier¹, Mohamedou Sow^{1

2}, Pierre Ciret^{1

2}

Affiliations

¹ University of Bordeaux, EPOC, UMR 5805, 33120 Arcachon, France.
² CNRS, EPOC, UMR 5805, 33120 Arcachon, France.
³ Institute of Marine Research, 9007 Tromsø, Norway.
⁴ Akvaplan-niva, Fram Centre for Climate and the Environment, 9296 Tromsø, Norway.
⁵ Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, 9037 Tromsø, Norway.
⁶ Centre for Autonomous Marine Operations and Systems, Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway.

Abstract

Marine organisms living at high latitudes are faced with a light climate that undergoes drastic annual changes, especially during the polar night (PN) when the sun remains below the horizon for months. This raises the question of a possible synchronization and entrainment of biological rhythms under the governance of light at very low intensities. We analyzed the rhythms of the mussel Mytilus sp. during PN. We show that (1) mussels expressed a rhythmic behavior during PN; (2) a monthly moonlight rhythm was expressed; (3) a daily rhythm was expressed and influenced by both sunlight and moonlight; and (4) depending on the different times of PN and moon cycle characteristics, we were able to discriminate whether the moon or the sun synchronize the daily rhythm. Our findings fuel the idea that the capability of moonlight to synchronize daily rhythms when sunlight is not sufficient would be a crucial advantage during PN.

Keywords: Biological sciences; Evolutionary biology; Zoology.