Abstract
The photobiology of sea anemones in shallow waters has been studied extensively in recent decades, while that of deep-dwelling species remains unclear. There is evidence that many deep-sea organisms are sensitive to blue light, and it may hold for sea anemones as well. The present study tested the hypothesis that the sea anemone Cribrinopsis japonica, caught at the depth of 800 m, is photosensitive to blue light, focusing on whether this anemone (1) showed behavioural responses to blue light, (2) possessed colour sensitivity, and (3) detected diminished intensity of light. When exposed to blue and red light separately, the anemone was behaviourally more sensitive to blue light than red light. The initiated behaviour was positive and immediate, and consisted of an increase in the area covered by tentacles and contraction of the column, which is considered as preparatory feeding behaviour. The anemone’s sensitivity to diminished intensity of light within the peak wavelength of bioluminescence opens up the possibility that the deep-sea anemone senses the presence of bioluminescent organisms.
Acknowledgements
We thank the staff at the Nyuzen Deep Seawater Facility for providing the specimens. We also thank the anonymous reviewers for their constructive comments and suggestions that improved the quality of our manuscript.
Disclosure statement
No potential conflict of interest was reported by the authors.
Supplementary material (Video S1)
The supplementary material for this article is available via the Supplemental tab of the article’s online page at http://dx.doi.org/10.1080/17451000.2015.1047382