Exploring seasonal variability in mixed layer depth with Ocean Observatories Initiative Ocean Data Labs

Seasonal variability in water column stratification and the drivers of that change is a core topic in most introductory oceanography courses. However, with static textbook cartoons, students often struggle to conceptualize salinity and temperature impacts on density and the physical dynamics that alter mixing regimes. As part of an Ocean Observatories Initiative (OOI) Data Labs Workshop we developed a series of exercises that will address this teaching challenge. The OOI is amassing a wide range of geological and oceanographic data at advanced research arrays in the Atlantic and Pacific Oceans. Sorting through and downloading the data presents challenges for educators looking for activities they can quickly implement in their classrooms. For this activity, we compiled several years of temperature, salinity, wind speed, and heat flux data from the OOI Irminger Sea Array into a publicly available interactive widget. Students are guided through a series of orientation and interpretation questions as they zoom in and out on the data and view temperature data as both time series and depth profiles. At the end of the exercise students should be able to describe how atmospheric processes mix surface water and alter thermal structure of the sub-polar North Atlantic Ocean. In addition, they will have practiced making sense of data outliers and gaps, reading time-series and depth profile plots, and communicating that information in words. This exercise lays the foundation for several possible extensions, also using OOI Data Labs, that have students compare dynamics in the North Atlantic and North Pacific, consider deep water formation in the North Atlantic, and link mixed layer dynamics to seasonal phytoplankton blooms.