A snapshot of turbulence in the Northeastern Magellan Strait

First-ever measurements of the turbulent kinetic energy (TKE) dissipation rate in the northeastern Strait of Magellan (Segunda Angostura region), obtained in March 2019, are presented. During the microstructure measurements, the magnitude of the reversing tidal current ranged between 0.8 and 1.2 m s⁻¹. The probability distribution of the TKE dissipation rate in the water interior above the bottom boundary layer was lognormal, with a high median value of ε_MS(med) = 1.2 × 10⁻⁶ W kg⁻¹. Strong vertical shear, ranging from 1 × 10⁻² to 2 × 10⁻² s⁻¹, in the weakly stratified water interior resulted in a subcritical gradient Richardson number (Ri < 10⁻¹–10⁻²). In the bottom boundary layer (BBL), both the vertical shear and the TKE dissipation rate decreased exponentially with distance from the seafloor (ξ), leading to a turbulent regime characterized by an eddy viscosity K_M ≈ 10⁻³ m² s⁻¹. This parameter varied with time and location, while remaining independent of the vertical coordinate in the upper part of the BBL (for ξ ≳ 2 m above the bottom).