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
Affiliations
Damien Tran
University of Bordeaux, EPOC, UMR 5805, 33120 Arcachon, France; CNRS, EPOC, UMR 5805, 33120 Arcachon, France; Corresponding author
Hector Andrade
Institute of Marine Research, 9007 Tromsø, Norway
Lionel Camus
Akvaplan-niva, Fram Centre for Climate and the Environment, 9296 Tromsø, Norway
Peter Leopold
Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, 9037 Tromsø, Norway
Carl Ballantine
Akvaplan-niva, Fram Centre for Climate and the Environment, 9296 Tromsø, Norway
Jørgen Berge
Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, 9037 Tromsø, Norway; Centre for Autonomous Marine Operations and Systems, Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway
Guillaume Durier
University of Bordeaux, EPOC, UMR 5805, 33120 Arcachon, France
Mohamedou Sow
University of Bordeaux, EPOC, UMR 5805, 33120 Arcachon, France; CNRS, EPOC, UMR 5805, 33120 Arcachon, France
Pierre Ciret
University of Bordeaux, EPOC, UMR 5805, 33120 Arcachon, France; CNRS, EPOC, UMR 5805, 33120 Arcachon, France
Summary: 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.
