oceans 1

what are the four large inter connected ocean basins

atlantic, pacific, indian, southern

major seas connected to atlantic

Mediterranean, Black, Baltic, Caribbean, gulf of Mexico

major seas conneceted to the indian ocean

Persian Gulf, Red Sea, Arabian Sea

major seas connected to the pacific ocean

many marginal seas (bering sea, tasman sea)

breifly explain the origions of the oceans

lots of comets in early stages of earth as well as volcanic eruptions (>95% H2O) even though most of this water existsed in a vapour state

describe the composition of sea water 

in constant flux over geo time, an avg of 3.5% (varying from 1.0-4.1%) dissolved salt along with Mg, Ca, K, CL^- and SO4². these ions enter the ocean from valconoes and hydrothermal activity. 

describe how salt is removed from the ocean

CaCO3 to shells of marine organisms and creation of minerals

what makes salinity lower at the eqautor

high precipitation due to low P area

explain salinity variation with depth

Salinity decreases with depth, as most salinity addition occurs at the surface level (halocline). this relationship, combined with the T, produces up and down welling and drives thermohaline circulation.

what is global average sea surface T 

~17 C can range from (-2C to 36C )

describe the variation sin T - depth variation levels 

At mid-to-low lats there is significant variation in water T with change in depth (thermocline). At higher lats, T change is very minimal with a change in depth (no thermocline). 

thermohaline circulation

the denser water sinks, and the less dense water rises. this process is important for distributing heat, nutrients and maintaining the current climate system

density _____ as T ______

decreases, increases

density _____ as salinity _______

increases, increases

surface currents

currents that affect the circulation of seawater within the upper 100m of water, some can travel 1000s of kms 

equatorial currents

currents that follow the eqautor, can flow in two directions

eddies

smaller currents that are found on coast lines, margins of gyres and along equatorial currents.

what drives surface currents 

shear of wind, Coriolis effect, pressure gradients in water, physical barriers

the average flow direction of surface currents is_______ to the flow of the wind

perpendicular

Ekman spiral

Water initially flows in the direction of the wind; the effect of the Coriolis effect and friction causes the current to deflect to the right (in N hemi). This effect becomes more pronounced when travelling deeper, creating this effect.

ekman transport

the net flow direction of the surface current (perp to the surface wind)

the atmosphereic surface winds that blow from NE to SW

NE trade winds

gyres

a circular flowing ocean current that is a product of Ekman transport along with pressure gradient forces and physical barriers. found in all major ocean basins clockwise in Nhemi and counterclockwise in Shemi. large scale

explain the relationship between Ekman trasport and downwelling

In areas with shore-parallel winds, Ekman transport occurs and produces zones where near-surface water sinks and the reverse.