Properties of Seawater Density review Mixing Dissolved Gases

Pressure in the Ocean Hydrostatic Equation Hydrostatic Balance

Density: amount of mass per unit volume Units: kg m -3 Linear Equation for “in situ” Density

A different way to express density

In situ Temperature Temperature of a particle of water measured at a particular depth and pressure (no correction for compressibility effects) Surface Deep ocean T1T1 T2T2 T1=θ1T1=θ1 T2≠θ1T2≠θ1 At the ocean surface In Situ and Potential Temperature are the same! θ1θ1 θ1θ1 Potential Temperature Temperature that a particle would have if raised adiabatically to the surface of the ocean (corrects for the effects of compression occurring at great depth  make the particle warmer)

In situ Density Potential Density

Tracking Water Masses on TS diagrams

Worlds ocean Water Masses

How do you mix water masses in the ocean?

Molecular diffusion Turbulent diffusion

Horizontal Stirring and Mixing

Mixing of two water masses with same Density O 1 T 1 S 1 O 2 T 2 S 2 Vertical Stirring and Mixing

y z + _ Mixing along surfaces of Constant Density Surfaces of constant density

y z + _ Mixing along surfaces of Constant Density Along - Isopycnal diffusive mixing Surfaces of constant density

y z + _ Along - Isopycnal diffusive mixing Across - Isopycnal diffusive mixing Mixing across surfaces of Constant Density Surfaces of constant density

y z + _ the “skew flux” Diapycnal Mixing Definitions of Mixing Surfaces of constant density

y z + _ the “skew flux” advection Diapycnal Mixing turbulent diffusion Definitions of Mixing Surfaces of constant density

Diabatic exchanges with the atmosphere at the surface Adiabatic changes and Mixing in ocean interior T 1 S 1 T 2 S 2

Surface: Wind stirring and vertical mixing in the surface layer Surface fluxes of heat and salt  buoyancy fluxes Surface Waves Interior: Along Isopycnal eddies and fronts Across Isopycnal internal wave breaking Bottom: Breaking internal waves over rough topography (ref: article) Summary of major mixing processes in the Ocean

Dissolved Gasses Air Seawater Total pressure = sum of partial pressures

Oxygen

Dissolved Gases in the Ocean Oxygen profile Anoxic environment compensation depth Respiration: Animal, plants and microbial decomposition

Dissolved Gases in the Ocean Oxygen profile

Why is the pH of seawater close to neutral? seawater pH=

Carbon Dioxide and Carbonate system Why is it important? 1. Regulates temperature of the planet 2. Important for life in the ocean 3. Regulates the pH of water

Carbonic Acid Bicarbonate Ion Sources for acidity in the ocean Carbon Dioxide and Carbonate system Carbonate