A video-plankton and microstructure profiler for the exploration of in situ connections between zooplankton and turbulence

Turbulence and mixing are ubiquitous in the environment of planktonic organisms and critical in large-scale physical and chemical oceanographic budgets. Recent studies have shown conflicting results on the contribution of zooplankton to ocean mixing as well as the impact of turbulence on zooplankton feeding and swimming behavior. Some of the confusion arises from the lack of properly resolved, simultaneous and co-located observations of zooplankton and turbulence. This paper introduces and discusses results from preliminary deployments of a Video Plankton Recorder–Vertical Microstructure Profiler (VPR–VMP), which is shown to provide good quality, high-resolution, simultaneous observations of zooplankton and turbulence. Non-turbulent shear spectra associated with a zooplankton layer are discussed in terms of automating the rejection of unreliable dissipation estimates, the shear created by individual organisms and profiler avoidance. Comparing these fine-scale observations of zooplankton and turbulence with bulk measures and possible future improvements are also discussed.