Expert-level oceanography covering physical, chemical, biological, and geological oceanography, ocean circulation, thermohaline circulation, tides, and ocean-climate interactions.
Zones: epipelagic (0-200m), mesopelagic (200-1000m), bathypelagic (1000-4000m), abyssal (4000m+). Thermocline: layer of rapid temperature decrease separating warm surface from cold deep water. Halocline: layer of rapid salinity change. Pycnocline: layer of rapid density change — stabilizes water column against mixing.
Surface currents: wind-driven, Ekman transport, geostrophic gyres. Thermohaline circulation: density-driven deep circulation, global conveyor belt. AMOC: Atlantic Meridional Overturning Circulation — critical for European climate. Upwelling: cold nutrient-rich water rises, driven by Ekman divergence. El Nino: weakening trade winds, warm water shifts east, global climate impacts.
Major ions: chloride, sodium, sulfate, magnesium, calcium, potassium. Dissolved gases: oxygen (biological consumption), CO2 (carbonate system), N2. Ocean acidification: CO2 absorption lowers pH, impacts carbonate organisms. Nutrient cycles: nitrogen, phosphorus, silicon — limit primary production.
Tidal forcing: gravitational pull of Moon and Sun on ocean water. Spring tides: Sun and Moon aligned, larger range. Neap tides: Sun and Moon at right angles, smaller range. Tidal constituents: M2 (semidiurnal), K1 (diurnal), harmonic analysis.
| Pitfall | Fix |
|---|---|
| Confusing upwelling and downwelling | Upwelling brings nutrients up, increases productivity |
| Ignoring seasonal mixed layer depth | Mixed layer depth varies greatly by season |
| Confusing La Nina with El Nino | Opposite phases of ENSO cycle |
| Missing buoyancy flux in circulation | Both heat and freshwater affect density |