Introduction to the HydrosphereIntroduction to the Hydrosphere

ObjectiveObjective

• Students will understand the components of the hydrosphere.

• Students will know the composition of ocean water, the physical structure of the ocean, and how the ocean is important to humanity.

Review: The Hydrosphere IReview: The Hydrosphere I

• Hydrosphere: the combined mass of water found on, under, and over the surface of the Earth

• Recall that the hydrosphere is connected to the other spheres of the Earth System

• Can anybody come up with one way that the hydrosphere is connected to another sphere?

Review: The Hydrosphere IIReview: The Hydrosphere II• The Water Cycle describes how the

hydrosphere is connected to the atmosphere, cryosphere, biosphere and lithosphere

The World’s Water IThe World’s Water I

• Most of the world’s water is in the ocean basins (97%)

• A much smalleramount (3%) is freshwater• Only 1% of the freshwater iseasily accessible

The World’s Water IIThe World’s Water II

The Importance of Water IThe Importance of Water I

• Water is a necessity for life on Earth• (1) Organisms need it to live• (2) Growing food• (3) Transportation• (4) Industry• (5) Other uses

Water is important to industry

The Importance of Water IIThe Importance of Water II• Water use varies from country to country,

poorer countries use water more for agriculture, and richer countries use water more for industry

The Importance of Water IIIThe Importance of Water III

• The world's six billion people are already appropriating 54 per cent of all the accessible freshwater contained in rivers, lakes and underground aquifers.

• By 2025 humankind's share will be 70 per cent

• As the world continues to industrialize, water demand will likely increase

The Importance of Water IVThe Importance of Water IV• Conflicts and wars have been

fought over water rights• Middle East fighting over the rights

to the Jordan River water• Water wars over Los Angeles water

access in California• "If the wars of this century were

fought over oil, the wars of the next century will be fought over water.“ - World Bank vice president

(Ismail Serageldin), 1995

The Importance of Water VThe Importance of Water V

• Nonrenewable resources—Can’t be replaced in nature very quickly

Vs.• Renewable resources—Can be replaced

in nature very quickly, once you use up the resource, it’s gone

• Do you think water is a renewable or nonrenewable resource? Explain

Ocean Water IOcean Water I

• Ocean water is commonly called “sea water”

• Composed of the following:• (1) Dissolved gases (including oxygen

and carbon dioxide)• (2) Dissolved nutrients (nitrates and

phosphates)• (3) Dissolved solids (salts)• (4) Suspended solids

Ocean Water IIOcean Water II• Salinity: The measure of the amount of

dissolved salts in seawater.• Salinity is usually measured in parts per

thousand (ppt), 1 ppt is 0.1%• The salinity of seawater varies:• Where is the salinitythe greatest? Theleast? Why?

Ocean Water IIIOcean Water III

• Density of freshwater = 1.0 g/cm3

• Density of saltwater = 1.02 g/cm3-1.03 g/cm3

• Which type of water sinks?

• Freshwater / Saltwater Demonstration

Ocean Water IVOcean Water IV• Ocean water absorbs light, this heats up ocean

water. However, some light is reflected.• Why does ocean water appear blue?• Blue wavelengths are absorbed the least by the

deep ocean water and are scattered and reflected back to the observer’s eye

• Why does ocean water appear black?• All light is absorbed by the water and little is

reflected back.• Why does ocean water appear green?• Living organisms reflect green light

Ocean Water VOcean Water V

• The temperature of the ocean water decreases with depth, in the area called the thermocline (see the diagram)

• There are a number of environments that are depth /temperature dependent. We willdiscuss these later.

Three major layers:(1) Epipleagic zone(2) Thermocline zone(3) Bottom zone

Ocean Water VIOcean Water VI• Scientists have divided the ocean into five main layers. These layers, known as "zones", extend

from the surface to the most extreme depths where light can no longer penetrate. These deep zones are where some of the most bizarre and fascinating creatures in the sea can be found. As we dive deeper into these largely unexplored places, the temperature drops and the pressure increases at an astounding rate. The following diagram lists each of these zones in order of depth.

Fundamentals of Oceanography IAFundamentals of Oceanography IA

• Ocean: Large body of salt water• Five principle oceans in the world• These oceans cover over 70% of the

surface of the Earth

Fundamentals of Oceanography IBFundamentals of Oceanography IB

• Some oceans are broken into southern / northern parts

• Seas: Large body of water marked off by land boundaries

• Examples:• North Sea• Weddell Sea• Ross Sea• Caribbean Sea

Fundamentals of Oceanography IIFundamentals of Oceanography II

• What is oceanography? Oceanography is the study of the great bodies of salt water comprising all the oceans and seas that cover nearly three-fourths of the surface of the earth, and the scientific study of the physical, chemical, and biological aspects of the so-called world ocean. The major goals of oceanography are to understand the geologic and geochemical processes involved in the evolution and alteration of the ocean and its basin, to evaluate the interaction of the ocean and the atmosphere so that greater knowledge of climatic variations can be attained, and to describe how the biological productivity in the sea is controlled.

Fundamentals of Oceanography IIIFundamentals of Oceanography III

• The ocean floor isn’t flat, there is underwater topography (called bathymetry)

• Tectonics• Mid ocean ridge system• Sea mounts• Black smokers• White smokers• Fault zones• Trenches

Fundamentals of Oceanography Fundamentals of Oceanography IVA IVA

• Mid ocean ridge extends for over 49,000 miles, a place where new ocean crust is forming

Fundamentals of Oceanography Fundamentals of Oceanography IVBIVB

• The mid ocean ridge system is essentially a long chain of volcanoes, a place where magma comes to the bottom of the ocean floor

• The ocean floor spreads apart away from the ridges

Fundamentals of Oceanography VFundamentals of Oceanography V

• Seamount: A mountain rising from the ocean seafloor that does not reach to the water's surface, and thus is not an island, extinct volcano

• Can provide habitats for marine species that are not found on or around the surrounding deeper ocean bottom

• Navigation hazards and good fishing

Fundamentals of Oceanography Fundamentals of Oceanography VIAVIA

• Hot spot—A location on the Earth's surface that has experienced active volcanism for a long period of time

• Hot spots are visible in ocean basins as a series of islands / seamounts (Hawaii)

Fundamentals of Oceanography Fundamentals of Oceanography VIBVIB

• Hawaiian-Emperor Seamount Chain, which is a whole series of islands / seamounts formed from the Hawaii hot spot:

Fundamentals of Oceanography VIIFundamentals of Oceanography VII

• Black smokers: A type of hydrothermal vent found on the ocean floor

• Unique ecosystems near both types of vents• Organisms around these vents don’t require sunlight to live, but chemicals - Possible extractable ore deposits• White smokers: White smokers are a type of

hydrothermal vent that emits lighter-hued minerals than

black smokers. They are generally cooler too.

Fundamentals of Oceanography VIIIAFundamentals of Oceanography VIIIA

• Faults, which are zones where rocks are displaced (moved), can occur underwater, below oceans and/or seas

• Tsunami: Is a series of waves created when a body of water, such as an ocean, is rapidly displaced

• Causes of tsunamis: (1) Displacement along a fault, (2) Underwater volcanic eruption, (3) Underwater avalanche, (4) Impact of an extraterrestrial body

• DID YOU KNOW? The largest tsunami recorded measured 210 feet, about 18 stories above sea level, when it reached Siberia's Kamchatka Peninsula in 1737.

Fundamentals of Oceanography VIIIBFundamentals of Oceanography VIIIB

• A tsunami struck multiple countries in Africa and Asia in 2004 due to an underwater earthquake

• Seawalls are built to protect coastal cities from

tsunamis• Tsunami warning network Watch tsunami videos

Fundamentals of Oceanography Fundamentals of Oceanography IXAIXA

• Trench: A relatively deep, linear and narrow oceanic feature that is formed by plate subduction.

• Deepest parts of the ocean floors• The deepest trench: Mariana Trench

(10,739 m (35,787 ft))• Chemosynthetic (turning chemicals into

carbon) communities thrive in certain deep trenches areas

Fundamentals of Oceanography Fundamentals of Oceanography IXBIXB

• The Puerto Rico Trench between the North American and Caribbean Plates:

Ocean Currents IOcean Currents IThe major surface currents in the world’s oceans are caused by prevailing winds. The

currents may be cold, as in the instance of the West Wind Drift, or warm, as the Gulf Stream. Currents circulate in paths called gyres, moving in a clockwise direction in the northern hemisphere and a counterclockwise direction in the southern hemisphere.

Ocean Currents IIOcean Currents II

• Density Current: Different densities caused by a difference in temperature and salinity.

• Surface Current: Can move as fast as 100 km a day and effect the top 200 m of the ocean. Driven by winds.

Ocean Currents IIIOcean Currents III• Upwelling: The upward motion of ocean water.

Cold water moves from the bottom to the surface. These waters are rich in nutrients and very productive for fisherman. High in oxygen.

• Upwelling = good fishin’!

Ocean Currents IVOcean Currents IV• Life in the oceans is not uniformly abundant. Because of the low

ratio of surface water to deep water and the lack of seasonal nutrient enrichment, much of the open ocean is a watery desert, especially the tropical seas. The most productive areas are the coastal regions, areas of upwellings (see below), and the Arctic and Antarctic oceans

• The rich Antarctic waters are pulled away from the shore and become part of the Antarctic Circumpolar Current, also known as West Wind Drift. This current, the strongest ocean current on earth, is partially diverted by the southern tip of South America, forming the Humboldt Current off the coast of Peru. As the surface water is pulled out by winds, the nutrient-rich deep water replaces it, aided by the absence of a continental shelf. This is an important upwelling region, and it supports an enormous amount of life. Copepods and opossum shrimp replace the krill of the Antarctic. Feeding on these crustaceans are immense schools of small fish that, in turn, are consumed by seabirds, replacing whales at the top of the food web.

Ocean Currents VOcean Currents V

• The flow of ocean currents plays a dominant part in the climate of many of the Earth’s regions

• The world’s oceans collect heat and transport it around the world

Ocean Resources IAOcean Resources IA

• Fishing is very important in provide world societies with protein

• World total of 86 million tons of fish were captured in 2000

• It will be necessary to manage ocean fisheries in the coming years to make sure the number of fish caught never makes it to zero

• Predictions are that the sea can yield only about 25 percent more than the present amount of organic food resources.

Ocean Resources IBOcean Resources IB• Fisheries: is the name of the business of

harvesting fish and other marine animals and plants in order to make a living. Fisheries include: (1) large industrial-scale operations with foreign fishermen who process their catch for export and commercial sales, (2) small-scale operations by local fishermen who primarily supply nearby markets, (3) aquaculture farms which raise marine animals and fish in a maintained environment, and (4) businesses that produce fish products.

• Exclusive Economic Zone (EEZ): More than 90% of world marine fish catch comes from the 10% of the oceans closest to land. This area is included in the Exclusive Economic Zone (EEZ). The EEZ refers to the coastal waters that lie adjacent to the coast and extend 200 nautical miles offshore.

Ocean Resources ICOcean Resources IC

• Countries have exclusive rights within the EEZ

Ocean Resources IIAOcean Resources IIA• Petroleum resources can be found off

of shorelines in oceans and/or seas• There are rocklayers under sea/ocean water thathold petroleum and trap it

Simplified cross-section showing a slice through the geologic layers under the Gulf of Mexico

Ocean Resources IIAAOcean Resources IIAA• Oil platforms are situated in waters off

of coastlines, including in the Gulf of Mexico

• These platforms are shut down when hurricanes approach

17 percent of the world petroleum production

Ocean Resources IIIOcean Resources III• The ocean is used for shipping products

from one country to another• Large number of products traveling

from China to the USA• Panama Canal expansion

Ships can spill oil (or other chemicals) or can create noise pollution, adversely affecting the marine environment

Ocean Resources IVOcean Resources IV

• Tourism is also an important industry in the oceans

• Eco-tourism

Ocean Resources VOcean Resources V

• Tidal energy farms• A lot of wind energy can be harnessed

by placing windmills out in seas and/or oceans. This is commonly called “offshore wind”

Ocean Resources VIOcean Resources VI• Desalinization plants: Plants that

remove excess salt and other minerals from water

• Desalinization of ocean water is very important in the dry Middle East, and may be increasingly more important in the future, worldwide

Ocean Resources VIIOcean Resources VII

• Mining operations are conducted in and under the ocean

• Diamonds, gold, silver, metal ores, sand, salt, and gravel mines

Climate Change & the Climate Change & the OceansOceans

Fun FactFun Fact

• Did you know? If all the gold suspended in the world's seawater were mined, each person on Earth could have about 9 pounds of gold.

ReferencesReferences

• http://www.unesco.org/water• http://www.worldwater.org• http://www.loc.gov• http://www.dictionary.com• http://oceanexplorer.noaa.gov• http://www.wikipedia.org• http://marinebio.org• http://www.mvtimes.com• http://www.aip.org• The Little Giant Book of Science Trivia