* The oldest shell middens from South Africa have been dated in 140,000 years old * Modern science is based on the application of the scientific method Lecture 2
* In the middle, ascending mantle material makes a mid ocean ridge * In areas where two continents are pushing against each other, one sinks underneath the other producing subduction zones that create deep trenches * Solid water (ice) displaces more volume than liquid water, therefore it floats * Seawater contains dissolved gasses that are exchanged with the atmosphere: gas exchange * The ocean is usually layers or stratified
* Layers are separated by thermoclines and haloclines
* Surface layer (mixed layer): down to 100-200 m, mixed by wind and currents * Intermediate layer: down to 1000-1500 m ,separated by the main thermocline * Deep layer: below 1500 m, very stable conditions
* The Coriolois effect is caused by the curvature and rotation of the Earth, it creates circular movement of water and air particles * The movement from the surface layer of water is transmitted to the water below, called the Ekman spirtal or Ekman transport * Because denser water sinks, it leaves a void that is filled in by less dense water called the Great Ocean Conveyer * During new and full moon, the sun, moon, and Earth line up. Tidal forces due to the Sun reinforce those of the moon: spring tide * When the moon is at first or third quarter, the sun and moon are separated by 90 degrees. The forces of the sun and moon cancel causing: neap tide * Semidiurnal: two high tides and two low tides each day
* Diurnal: one tidal cycle per day
* In most places tides are mixed. Because of the diurnal contribution, there is a difference in height (the daily inequality) between the two high tides in a given day. * The size of wind waves depends on the fetch, the span of open water over which the wind blows Lecture 3
* Abiotic: environmental...