Ocean Structure and Circulation 1

Ocean Model Temperature Depth Surface Deeper WarmerColder 2

Ocean Model 3

“Warm” shallow surface layer Cold deep layer Transition Zone Ocean Model 4 How do the layers form?

Surface Layer Deep Water Transition Zone 5 Homogeneous Ocean

Taking the Temperature 6 Conductivity Temperature Depth C T D

Ocean Temperature Deep Water 90% of the total volume of ocean is this cold, deep water. At depths greater than 1000m, temperature is approximately 4ºC (even in the tropics!!). windows.ucar.edu Why do layers form? Thermocline = Temperature Change Surface Layer Transition Zone 7

Mass per unit volume Lighter 1000 kg/m 3 Denser kg/m 3 hawaiianphotos.net Because of Density Lighter 100 kg/m 3 Denser 19,300 kg/m 3 Slashfood.com 8

Ocean Density Surface Layer Deep Water Seawater density is controlled by Temperature and Salinity In the ocean, Temperature has a greater effect on density windows.ucar.edu Pycnocline = Density Change Pycnocline Transition Zone 9

Surface Layer Deep Water Boundary Transition Zone Thermocline & Pycnocline 10

Surface Layer Deep Water Boundary 11 Mixed Warmed and lit by sun Photosynthesis Cold, Dark, No Photosynthesis Less Nutrients, More Nutrients

Surface Ocean Warm Lit by the sun Has photosynthesis Less nutrients Deep Ocean Cold Dark No photosynthesis More Nutrients 12 Summary