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Abstract Vertical profiles of temperature microstructure at 95 stations were obtained over the Beaufort shelf and shelfbreak in the southern Canada Basin during a November 2018 research cruise. Two methods for estimating the dissipation rates of temperature variance and turbulent kinetic energy were compared using this data set. Both methods require fitting a theoretical spectrum to observed temperature gradient spectra, but differ in their assumptions. The two methods agree for calculations of the dissipation rate of temperature variance, but not for that of turbulent kinetic energy. After applying a rigorous data rejection framework, estimates of turbulent diffusivity and heat flux are made across different depth ranges. The turbulent diffusivity of temperature is typically enhanced by about one order of magnitude in profiles on the shelf compared to near the shelfbreak, and similarly near the shelfbreak compared to profiles with bottom depth >1,000 m. Depth bin means are shown to vary depending on the averaging method (geometric means tend to be smaller than arithmetic means and maximum likelihood estimates). The statistical distributions of heat flux within the surface, cold halocline, and Atlantic water layer change with depth. Heat fluxes are typically <1 Wm⁻², but are greater than 50 Wm⁻²in ∼8% of the overall data. These largest fluxes are located almost exclusively within the surface layer, where temperature gradients can be large. 

The Ocean Observatory Initiative (OOI) funded by the U.S. National Science Foundation established four deep ocean observing sites between summer 2013 and spring 2015: Argentine Basin (42˚ 58.9’ S, 42˚ 29.9’ W, water depth 5200 m), Southern Ocean (54 ˚ 28.1’ S, 89˚ 22.1’ W, 4800 m), Station Papa (50˚ 4.2’ N, 144˚ 47.9 W, 4219 m), and Irminger Sea (59˚ 58.5’ N, 39 ˚ 28.9’ W, 2800 m). Each site was instrumented with four closely-spaced moorings of various design supporting a variety of sensors. As no single OOI mooring in these arrays provides temperature, salinity and horizontal velocity information over the full water column, observations from two or more moorings were combined to produce vertical profiles at ½-dbar vertical resolution of sea water temperature, salinity, east and north velocity and vertical displacement. These profile data are reported here. 

Abstract The meroplanktonic larvae of many invertebrate and vertebrate species rely on physical transport to move them across the shelf to their adult habitats. One potential mechanism for cross‐shore larval transport is Stokes drift in internal waves. Here, we develop theory to quantify the Stokes velocities of neutrally buoyant and depth‐keeping organisms in linear internal waves in shallow water. We apply the analyses to theoretical and measured internal wave fields, and compare results with a numerical model. Near the surface and bottom boundaries, both neutrally buoyant and depth‐keeping organisms were transported in the direction of the wave's phase propagation. However, neutrally buoyant organisms were transported in the opposite direction of the wave's phase at mid depths, while depth‐keeping organisms had zero net transport there. Weakly depth‐keeping organisms had Stokes drifts between the perfectly depth‐keeping and neutrally buoyant organisms. For reasonable wave amplitudes and phase speeds, organisms would experience horizontal Stokes speeds of several centimeters per second—or a few kilometers per day in a constant wave field. With onshore‐polarized internal waves, Stokes drift in internal waves presents a predictable mechanism for onshore transport of meroplanktonic larvae and other organisms near the surface, and offshore transport at mid depths.