Oceans and Rivers

Question 1

How does the moon impact tides

Answer 1

Spring tide is highest tide when 
sun-moon-Earth line up (new 
and full moon0
Neap tide occurs about 2 
weeks later (moon and sun at 
right angles to Earth)

Question 2

define what a delta is

Answer 2

where river meets the sea

• slope of river drops to zero and flow velocity drops as it enters standing body of water –it therefore drops its bedload
• shape depends on dominant shoreline process

Question 3

define emergent and submergent coasts

Answer 3

Emergent coasts occur when sea level falls relative to land level. Such as Hudson Bay when considering glacial isostatic rebound
Submergent coasts occur where sea levels rise relative to land level. This leads to former plains being flooded.

Question 4

define the purpose of barrier islands

Answer 4

Ridges of sand, made from former beach sediments, that form parallel to the shoreline.
Common with Submergent coasts

Question 5

Explain Sable Island and why it exists

Answer 5

It is on the edge of the continental shelf, at one time this was the edge of the North American Continent, when glaciers melted the oceans fill up separating the island from the mainland.

Question 6

Explain Surface currents

Answer 6

solar energy is absorbed by oceans and distributed by currents

• Earth’s rotation and Coriolis effect exert influence on ocean and atmospheric currents
• Gyres rotate clockwise in northern hemisphere and counterclockwise in southern hemisphere

Question 7

Explain Deep water currents.

Answer 7

Warm water (gulf stream) slowly cools and becomes more saline and sinks in the North Atlantic as it rises into higher latitude. 
Greatest density of water is at 4 degrees Celsius*****
This circulation overturns and mixes into the entire world ocean (70% of surface and brings nutrients to marine life). This is critical for the distribution of climates today.

Question 8

What would happen if all of the Ice on Greenland melts

Answer 8

It would dilute the water currents and impact the global conveyor belt and possibly wreck the global climate.

Question 9

Define Thermohaline Circulation

Answer 9

part of the large-scale ocean circulation that is driven by global density gradients created by surface heat and freshwater fluxes.

often called conveyor belt

Question 10

define wavebase

Answer 10

is the depth at which water is
not disturbed by waves; = ½ wavelength
-wave lengths are lower (up to 6 m)
during fair-weather, therefore wave base
is about 3 m; during storms wave length is
longer and wave base is deeper (a few to
several 10’s of metres)

Question 11

define longshore drift

Answer 11

Waves usually approach shore at a 
slight angle; wave crest bends 
(refraction). This creates a slight angle 
between swash and backwash creating 
a longshore current and longshore 
drift of sand

Question 12

Why are beaches in north America shrinking

Answer 12

• dams are trapping river sediment upstream

- longshore drift