The transition from summer stratification to winter stratification is considered for deep, dimictic Lake Superior. The fall transition is dynamically distinct from the better‐studied spring transition; it is characterized by a wind‐driven collapse of weakening summer stratification, a surface‐cooling–driven period during which the water column is essentially isothermal, and eventual onset of inverse (cold upper layer) stratifi...

High‐resolution dive depth and acceleration recordings from nearshore (Sarasota Bay, dive depth Tursiops spp.) were used to estimate the diving metabolic rate (DMR) and the locomotor metabolic rate (LMR, L O 2 /min) during three phases of diving (descent, bottom, and ascent). For shallow dives (depth ≤ 30 m), we found no differences between the two ecotypes in the LMR during diving, nor during the postdive shallow interval bet...

From May to July 2019, an array of moored equipment was deployed in Lake Superior to characterize the spatial and temporal scales of radiatively driven convection (RDC). Previous work suggested that convective plumes have horizontal scales on the order of tens of meters, posing a significant observational challenge. The centerpiece of the deployment was a large, two‐dimensional (2D) array of thermistors that provided resolutio...

Observations of radiatively driven convection in deep, ice‐free Lake Superior from a set of moorings and an autonomous glider are used to characterize the spatial and temporal scales of the phenomenon. The moored observations show that instability builds at the surface on scales of hours, water near the bottom of the lake begins warming roughly 6 h after sunup, and the water column homogenizes a few hours after sundown. Glider...

Wind‐driven turbidity plumes frequently occur in the western arm of Lake Superior and may represent a significant cross‐shelf transport mechanism for sediment, nutrient, and biota. Here, we characterize a plume that formed in late April 2016 using observations from in situ sensors and remote sensing imagery, and estimate the volume of cross‐shelf transport using both the observations and an idealized analytical model of plume...

Moorings equipped with thermistors that span the water column were deployed at up to seven locations throughout Lake Superior from October 2005 through May 2013. This year‐round, multi‐year, multi‐location, full water‐column record of the thermal structure reveals significant inter‐annual and spatial variability in Lake Superior's winter heat content, thermocline depth, and phenology. There is a stark contrast in thermal struc...

Directly measured velocity data collected in Lake Superior between 2008 and 2011 show that currents in the open waters of the lake are dominated by near‐inertial energy. The near‐inertial signal is composed almost entirely of clockwise rotation, with vertical structure dominated by the first baroclinic mode, where waters above and below the thermocline are roughly 180° out of phase with each other. The strength of the oscillat...

We use a one‐dimensional model, forced with realistic meteorological measurements, to determine to first order the sensitivity of summer surface water temperature, heat content, and vertical stratification scale to three forcing variables: air temperature, wind speed, and previous winter ice cover, all three of which have exhibited long‐term trends over the last few decades. Summer‐averaged surface temperature increases with i...

A 100‐yr‐long time series of water temperature measured just downstream of Lake Superior is used to produce proxy time series of open‐lake temperature. This analysis suggests that open‐water Lake Superior summer temperatures have increased by roughly 3.5°C over the last century, most of that warming occurring in the last three decades. Correspondingly, the length of the positively stratified season has increased from 145 d to...