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.

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

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 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 Temperatures 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

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

TIDES Tides - daily changes in the elevation of the ocean Due to the gravitational pull of the moon Most places have 2 high & 2 low tides each day

2 TIDE TYPES SPRING Tide During full & new moon (twice a month) largest tidal range moon-earth-sun are all in a straight line

2 Tide Types 2. NEAP Tide During 1st and 3rd quarter moons (twice a month) Smallest tidal range Moon-earth-sun at 90 degree angles

Estuaries Estuaries are sometimes called “marine nurseries” Partially enclosed area where freshwater from rivers meets saltwater (protected from waves) Nutrient rich from land runoff, highly productive salinity varies, often based on tides Estuaries are sometimes called “marine nurseries” habitats for many juvenile organisms, especially for fishes many fish are born and grow up in estuaries migrate to the open ocean

Intertidal Zone The area where the land meets the sea between high and low tides Organisms adapt to waves, wet or dry conditions, and changes in salinity

Coral Reef Clear, warm, coastal waters of tropics and subtropics Currents and waves constantly bring nutrients Coral secrete a hard external skeleton of calcium carbonate forming a stony structure of limestone New polyps attach to old coral and gradually build the reef

Coral Reef Vulnerable because: Grow slowly Disrupted easily Thrive only in clear, warm, shallow water of constant high salinity and temp 18-30C Increase in temp results in coral bleaching

Coral Reefs Fringing reefs Barrier reefs Atolls Submerged platforms of living coral extending from the shore into the sea (attached to land) Barrier reefs Follow the shore but are separated from it by water Great Barrier Reef is world’s largest Atolls Ring-shaped islands of coral in open sea Form on submerged mud banks or volcano craters Surround a seawater lagoon

Oceanic Pelagic Most of the ocean's water – open ocean Generally cold - hard to give a general temperature range because of thermal stratification andconstant mixing of warm and cold ocean currents Large fast swimming predatory fish

Oceanic Pelagic Euphotic zone -Lighted upper zone Photosynthesis Low nutrient levels High DO Bathyl – dimly lit middle zone – zooplankton and smaller fish

Oceanic Benthos Ocean bottom Abyssal – deep bottom very cold high pressure low DO enough nutrients to support 98% of species of ocean (dead decaying organisms fall)