Oceanography

The Vast World Ocean Nearly 71 percent of Earth’s surface is covered by ocean. Oceanography - includes geology, chemistry, physics, and biology to study all aspects of the ocean.

Ocean Basins The world ocean can be divided into four main ocean basins—the Pacific, Atlantic, Indian, and Arctic. The Pacific Ocean is the largest and deepest The Atlantic Ocean is half the size of the Pacific and not as deep The Indian Ocean is slightly smaller than the Atlantic The Arctic Ocean is 7 % the size of the Pacific

Topography of the Ocean Makes no sense without caption in book Topography is the arrangement of the natural and artificial physical features of an area.

Continental Margin Continental shelves – underwater extension of the continent contains important mineral deposits, large reservoirs of oil and natural gas, and huge sand and gravel deposits. Continental slope - connects the continental shelf and ocean floor Continental rise – gently sloping hill of accumulated sediments at the base of the continental slope. Makes no sense without caption in book

Continental Shelf

Abyssal Plain Abyssal plain - deep, level ocean floor Seamount – underwater volcano that may rise above the ocean Guyot - an eroded, flat-topped seamount. Deep ocean trenches -form where subduction occurs Makes no sense without caption in book

Ocean Floor Features Mid-Ocean Ridge – forms where seafloor spreading occurs

Mid-Ocean Ridges Hydrothermal vents form along mid-ocean ridges. These are zones where hot, mineral-rich water, escapes through cracks in the oceanic crust into surrounding water

Energy Resources from the Seafloor Oil and natural gas are the main energy products currently being obtained from the ocean floor.

Resources from the Seafloor Other major resources from the ocean floor include sand and gravel, evaporative salts, and manganese nodules. The offshore sand-and-gravel industry is second in economic value only to the petroleum industry.

The Composition of Seawater Salinity - amount of solids dissolved in water (35 ppt-parts per thousand or 3.5%) 2 main dissolved solids: Chlorine = 55% from earth’s interior (volcanoes) Sodium = 30.6% from chemical weathering of rocks (carried by rivers)

Processes Affecting Salinity Salinity varies from 33 to 38 ppt

Processes Affecting Salinity Processes that DECREASE the salinity of seawater: 1. Precipitation 2. Runoff 3. Ice melting Processes that INCREASE the salinity of seawater: 1. Evaporation 2. Freezing of sea ice Makes no sense without caption in book

Ocean Temperature Variation Temperature varies with the amount of sunlight, which depends on latitude. Thermocline – begins at 300 meters where there is a rapid change of temperature

Water Layers in the Tropics Makes no sense without caption in book

Ocean Zones 1. Surface Zone: sunny and shallow 2. Transition Zone: Includes the thermocline 3. Deep Zone: dark, a few degrees above freezing, high-density Makes no sense without caption in book

Ocean Density Affected by: Temperature Lower temp. = higher density Salinity Higher salinity = higher density Depth Deeper = higher density

Classification of Marine Organisms Marine organisms can be classified according to where they live and how they move. 1. Plankton - drift with the currents Phytoplankton - algae (plants) Zooplankton - animal

Nekton All animals that can swim/move on their own Fish, squids, turtles, etc.

Benthos Live on or in the ocean bottom Worms, coral, starfish

Marine Life Zones 3 factors are used to divide the ocean into distinct marine life zones: 1. availability of sunlight 2. distance from shore 3. water depth Makes no sense without caption in book

Waves obtain their energy and motion from wind Crest = top Trough = bottom Wave height = distance from trough up to crest Wavelength = distance from crest to next crest

Factors Affecting Waves wind speed length of time the wind has blown Fetch (distance wind blows)

Wave Motion (1) water particles move in a circle energy moves forward particles return to original position energy decreases with depth (2) Breakers - breaking depth = ½ wavelength - surf –turbulent water after wave breaks

Surface Currents Ocean current - mass of ocean water that flows from one place to another Flows horizontally Caused by wind friction Warm currents move from equator to poles Cold currents move from poles to equator

Ocean Surface Currents Makes no sense without caption in book Gyres - huge circular-moving current systems Coriolis effect - deflection of currents away from their original course as a result of Earth’s rotation.

Deep Ocean Circulation Vertical (up and down) movement of water Density currents = vertical currents of water due to density differences Upwelling = cold water rising from deep layers to replace warm surface water Brings nutrients to surface(good for fishing)

A Conveyor Belt

Effects of Upwelling Makes no sense without caption in book

SHORELINE PROCESSES/FEATURES Forces: Eroding Depositing Longshore Transport Wave impact Wave refraction Abrasion

Sea Erosional Features 1. Sea Cave 2. Sea Arch 3. Sea Stacks 4. Wave-cut platform

Depositional Feature 1. Spit 2. Baymouth Bar 3. Tombolo 4. Barrier Islands

Stabilizing/Protecting Features 1. Jetties or groins 2. Breakwaters 3. Seawalls 4. Beach nourishments

Stabilizing/protecting shores: Natural protectors: sand bars, sand dunes, coral reefs

Coral Reefs Fringing reef Atoll Barrier reef