Marjolaine Matabos (Post Doctoral Fellow, SEOS, UVic)
Understanding biological rhythms on the seafloor and their modulation by natural cycles (i.e. tides, 24h) has important implications for resource and ecosystem management. The VENUS Digital Stills camera (a.k.a. CMAP Cyclops) installed in Saanich Inlet proved to be a great tool to conduct in situ investigation of the behaviour of crustacean species in relation to natural cycles and habitat variability. In autumn 2009, a team of researchers from Spain, Italy and Canada began a 2-month study of the biological rhythms in Saanich Inlet. Fall is when bottom waters of the inlet, low in dissolved oxygen, are re-oxygenated by deep-water renewal events. The research team used the VENUS camera to document changes in the abundance of shrimp (Spirontocaris spp.) and squat lobster (Munida quadrispina), as well as bacterial mat coverage (Beggiatoa spp.) The abundances of these organisms served as an index of their activity. For example, some species migrate from the surface to the bottom following a given cycle, and will thus be absent from the seafloor at certain times of the day or tide. The 9-hour time difference between British Columbia and Europe permitted the team to carry out 24-hour photo time series, swapping camera control from Victoria to Barcelona or Rome, and then back to Victoria. To understand how species respond to changes in environmental conditions, biological data were compared to physical and chemical measurements (e.g. temperature, oxygen and nitrate concentrations, water pressure) provided by other VENUS network instruments. Research revealed that the shrimp displayed a tidal rhythmicity, which might correspond to changes in oxygen concentration, while the squat lobsters appeared to be more oxygen tolerant, with their numbers remaining constant throughout the entire experiment. I would like to thank everyone who has been collaborating on this project and made it possible:
Dr. Jacopo Aguzzi, Instituto de Ciencias del Mar (ICM-CSIC), Paseo Marítimo de la Barceloneta, Spain; Dr. Paolo Menesatti, Dr. Corrado Costa: AgritechLab – Agricultural Engineering Research Unit of the Agriculture Research Council (CRA-ING), Via della Pascolare, (Roma), Italy; Dr. Kim Juniper and PhD student Katleen Robert (Department of Biology, UVic).
