Lab 5 – Investigating Density and Stratification in the Ocean

Understanding properties that control the formation and movement of different water masses can give us insight into how heat energy is moved around the globe. The density of seawater plays a vital role in driving ocean circulation and determining primary production because of the fact that dense seawater sinks below less dense seawater. In this lab you will explore how salinity and temperature affect the density of seawater and how density can change with season and location.

Activities in this Lab

Learning Outcomes

  • LO1. Students will demonstrate basic data literacy in graph interpretation by identifying changes in temperature and salinity with depth.
  • LO2. Students will explain how T and S relate to density stratification and stability of water masses in the ocean using a T-S diagram.
  • LO3. Students will describe the development of a seasonal pycnocline and explain the differences between and temperate and polar latitudes.
  • LO4. Students will predict what has a more controlling effect on density – temperature or salinity.
  • LO5. Students will identify the implications of ocean warming on water column stability and biological productivity.

Background information

  • Key terms: halocline, thermocline, pycnocline, mixed layer, stratification, stability, water mass, CASW, AABW, NADW, AAIW, thermohaline circulation, temperate latitude, polar latitude
  • OOI Arrays: Coastal Pioneer and Argentine Basin
  • Sensors:
    • Coastal Pioneer Offshore Profiler Mooring Wire-Following Profiler
    • Argentine Basin Apex Profiler Mooring Wire-Following Profiler
  • Other need-to-know scientific background: