The Underwater Vision Profiler 6: an imaging sensor of particle size spectra and plankton, for autonomous and cabled platforms

Abstract

Autonomous and cabled platforms are revolutionizing our understanding of ocean systems by providing 4D monitoring of the water column, thus going beyond the reach of ship-based surveys and increasing the depth of remotely sensed observations. However, very few commercially available sensors for such platforms are capable of monitoring large particulate matter (100-2000 μm) and plankton despite their important roles in the biological carbon pump and as trophic links from phytoplankton to fish. Here, we provide details of a new, commercially available scientific camera-based particle counter, specifically designed to be deployed on autonomous and cabled platforms: the Underwater Vision Profiler 6 (UVP6). Indeed, the UVP6 camera-and-lighting and processing system, while small in size and requiring low power, provides data of quality comparable to that of previous much larger UVPs deployed from ships. We detail the UVP6 camera settings, its performance when acquiring data on aquatic particles and plankton, their quality control, analysis of its recordings, and streaming from in situ acquisition to users. In addition, we explain how the UVP6 has already been integrated into platforms such as BGC-Argo floats, gliders and long-term mooring systems (autonomous platforms). Finally, we use results from actual deployments to illustrate how UVP6 data can contribute to addressing longstanding questions in marine science, and also suggest new avenues that can be explored using UVP6-equipped autonomous platforms.

Constraining the Particle Size Distribution of Large Marine Particles in the Global Ocean With In Situ Optical Observations and Supervised Learning

“…This could allow a closer investigation of particle dynamics in the water column, a better diagnosis of the processes that cause deviations of PSD from a simple power law, and enable three‐dimensional reconstructions of size‐dependent processes such as particle sinking fluxes. Enhanced deployments of UVPs—also on Argo floats (Picheral et al., 2022)—combined with the approaches developed in this paper could also enable decadal or even annual estimates of global PSD and particle flux through the water column. Ultimately, a three‐dimensional view of particle abundance and size distribution in the ocean would shed light on an essential component of ocean biogeochemistry and ecosystem, and inform new models of the ocean's biological pump.…”

Recommendations for Plankton Measurements on OceanSITES Moorings With Relevance to Other Observing Sites

“…As such, they are optimally deployed on a cabled observatory. However, a recent successful long-term deployment on a mooring has been achieved [Picheral et al (2022)] opening an avenue for wider utilization. A practical overview of the challenges and potential of using imaging instruments to measure particles in the ocean is provided in Giering et al (2020).…”

Comparison of an In Situ Imaging Device and Net-Based Method to Study Mesozooplankton Communities in an Oligotrophic System

“…There are a wide range of tools which facilitate the study of zooplankton in situ. Examples of this technology include the zooglider (Ohman et al, 2018), ISIIS (Cowen and Guiginad, 2008), LOKI (Schulz et al, 2010), LOPC (Herman et al, 2004), PELAGIOS (Hoving et al, 2019), VPR (Davis et al, 1992), and UVP (Picheral et al, 2010;Picheral et al, 2022) (see Lombard et al, 2019 for a complete review of optical tools). Although these tools accomplish a similar goal, they have vastly different approaches and outcomes.…”

“…Although these tools accomplish a similar goal, they have vastly different approaches and outcomes. Some devices are independently towed (Cowen and Guiginad 2008;Hoving et al, 2019), while others are designed to be incorporated with oceanographic instrument rosettes (Picheral et al, 2010;Picheral et al, 2022). Illumination and imaging technology also varies between devices.…”

“…Illumination and imaging technology also varies between devices. Plankton cameras can include white-light (Hoving et al, 2019), single beam and two-beam red-light (Picheral et al, 2010;Picheral et al, 2022), shadowgraphy (Cowen and Guiginad 2008;Ohman et al, 2018), holography (Nayak et al, 2021), dark-field microscopy (Orenstein et al, 2020), and more. Additionally, these devices range in the quality of image taken, frequency of data collection, and volume sampled in a given profile (Lombard et al, 2019).…”