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Chapter 15 & 16

Water ResourcesTed Talk Video Water

The Water Cycle

• It involves

• condensation

• evaporation

• transpiration

• precipitation

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• Water Cycle: water molecules circulating between the Earth’s surface and the atmosphere.

The Water Cycle

Evaporation Transpiration

CondensationPrecipitation

Runoff

Seepage

Root

Uptake

The Water Cycle Properties of Water Supporting Life

High Specific Heat - fluctuations in heat are not as great as on land, reduce risk of temperature related problems

Buoyancy- physical support allows for larger sized creatures with less rigid support

Nutrient availability- nutrients are dissolved and “on tap” in surrounding waters

Waste elimination- wastes are quickly dissolved, dispensed, and diluted

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Global Water Distribution

• 71% of the Earth’s surface is covered in water

• 97% of that water is salt water: Unusable

• 3% is freshwater: Usable by humans

• 77% of the fresh water is frozen in icecaps and glaciers

• Fresh water is a limited resource

• Potable Water: Drinkable

Global Water Distribution

Fresh Water Biomes

• Total of fish species• Lentic Waters: Still

–Lakes & Ponds• Lotic Waters: Moving/flowing

–Streams, rivers

Earth’’’’s surface waterStreams, rivers, ponds, lakes and wetlands

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Over half have been drained and filled; many are now protected

Wetlands

• Marshes, swamps, bogs

• Very productive ecosystems;

• Ecosystem services slowing:- runoff, reducing

flooding, recharging groundwater, filtering pollutants

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How Wetlands Work

Eutrophic• High levels of

productivity

• Very Low O2

Oligotrophic

• Low amounts of nutrients Ex: P and N

• High O2

Productivity in a lake

Mesotrophic

• Some organic matter.

• Low O2

Mesotrophic

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Lakes & Ponds

• Littoral zone: - edge or shoreline

• Limnetic zone:- open water

• Profundal zone:- open water

beyond sunlight’s reach

• Benthic zone: - lake or pond

bottom

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• Aquifers: porous sediment that holds water • (2 types)

- Unconfined: porous rock covered by soil- Confined: surrounded by layer of impermeable rock or

clay• Recharge zone: An area in which water travels downward to

become part of an aquifer. • Percolation is the process of a liquid slowly passing through a filter.

Groundwater

Pollution

can enter

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• Cone of depression- an area where there is no longer any groundwater; may cause sinkholes

• Zone of saturation is at a depth were ground is filled with water

•Water table: uppermost layer at which water in an area fully saturates the rock or soil

•Falls in dry weather•Rises in wet weather

Groundwater

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The Ogallala Aquifer• The world’s largest known aquifer

• Great Plains of the U.S.

• 95% of water removed for irrigation (grains)

• Agriculture, municipal and industrial usage

• Removal rate is six times greater than the refreshing rate.

Groundwater

Major Aquifers of Georgia

1,2,3 – Floridan aquifer4. Claiborne, Clayton, Providence aquifers5. Cretaceous Aquifer

Groundwater Aquifer Subsidence

Area of Subsidence

Groundwater-related subsidence is the subsidence (or the sinking) of land resulting from groundwater extraction.

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Groundwater

Saltwater Intrusion

The movement of saltwater into freshwater aquifers, which can lead to

contamination of drinking water sources.

Porosity vs. Permeability

• Is the percentage of the total volume of a rock that has spaces or pores.

• The more porous a rock, the more water it can hold

• The ability of rock or soil to allow water to flow through it.

• Example: granite, sandstone, and limestone are permeable but clay is impermeable.

Marine Biomes

•71% of earth's surface•Currents distribute solar heatand regulate the earth's climate

•participate in nutrient cycles• reservoir for carbon dioxide -thus help regulate temperature of the troposphere

• Consist of coastal ocean, open ocean, coral reefs, estuaries, coastal marshes, and mangrove swamps.

• 2/3rds of population live

within 100 miles of the ocean

Ocean Terminology

4. Benthic- bottom

floor

5. Abyss- deepest

part of the ocean

6. Pelagic-Everything except areas near the coast

7. Photic-photosynthesis

8. Aphotic-no

sunlight

1. Intertidal- land exposed to tides

2. Neretic- covers continental shelf (coral reefs)

3. Oceanic-less productive

Ocean

divided vertically

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• Thermal Stratification• Epilimnion- at the surface and

warm water

• Thermocline-transition layer

between the mixed layer at the

surface and the deep water

layer.

• Hypolimnion- deeper water and

cold

Ocean water is vertically structured

• Oceans regulate the earth’s climate

– They absorb and release heat

– Ocean’s surface circulation

• Caused by winds and the movement of the earth

• The ocean currents move heat around the globe.

• Gulf Stream currents are rapid

and powerful• The warm water moderates

Europe’s climate

Ocean currents• Currents = the upper waters of the ocean composed of

vast riverlike flows

El Nińo

• Upwelling = the vertical flow of cold, deep water towards the surface – High primary productivity and lucrative fisheries– Also occurs where strong winds blow away from, or

parallel to, coastlines

Simulation

Ocean currents• Surface winds and heating create vertical currents Kelp forests

• Kelp = large, dense, brown algae growing from the floor of continental shelves

• Cold temperatures

• Shelter and food for organisms

• Absorbs wave energy and protects shorelines from erosion

• Used cosmetics, paints, paper, and soaps

• High Biodiversity

Open ocean systems

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Coral reefs

• Corals = tiny colonial marine organisms

• Coral reef = a mass of

calcium carbonate composed

of the skeletons of corals

Open ocean systems

• Highest areas of biodiversity and most abundant of ocean organisms (plankton, nekton, and benthos)

• Protect shoreline by absorbing

waves• Found in the Neritic Zone in

tropical waters

Causes of decline of Coral reefs around the world

1. Coral bleaching = occurs when zooxanthellae leave the coral

– Coral lose their color and die, leaving white patches

– From climate change, pollution, or unknown natural causes

Open ocean systems

2. Nutrient pollution causes algal growth, which covers coral3. Divers damage reefs by using cyanide to capture fish4. Acidification of oceans deprives

corals of necessary carbonate ions for their structural parts

Intertidal zone

• Changing tides cause rocky shores to be completely covered with water at certain times and completely exposed to the air and sunlight at others.

Salt marshes• Salt marsh = occur along coasts at temperate

latitude

– Tides wash over gently sloping, sandy, silty substrates

– High primary productivity

– Critical habitat for birds and commercial fish

and shellfish species

– Filter pollution

– Stabilize shorelines against storm surges

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Mangrove forests• In tropical and subtropical latitudes coast lines

• Mangroves = trees with unique roots

– Curve upwards for oxygen

– Curve downwards for support

• Nurseries for commercial fish and shellfish

• Nesting areas for birds• Food, medicine, tools,

construction materials

Estuaries• Estuaries = water bodies

where rivers flow into the ocean (freshwater mixes with saltwater)

– Wide fluctuations in salinity

• Critical habitat for shorebirds and shellfish

• Chesapeake Bay

• Largest estuary in the US.• Very productive

• High amounts of pollution

introduced

• Restoration program

introduced in the 80s• Transitional zone (Fish spawn

in freshwater, mature in salt water) Ex: Salmon

• Affected by development, pollution, habitat alteration,

and overfishing

• Excess nutrients introduced to ocean

due to runoff

• Can produce harmful algal blooms (red tide)

• The Gulf of Mexico’s “dead zone” is

currently the most notorious eutrophic body of water within the world.

• Hypoxia is a result of excess

nutrients in the water, more

specifically nitrates and

phosphates.

Human Impact on Coastal Zones

• Wetlands destruction• Toxic pollution• Beach erosion• Reduced resources

Energy from the Ocean

• We extract energy from oceans

• Crude oil and Natural gas• Oil spills damage fisheries

• Renewable energy sources, such as waves, tides, heat

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Emptying the oceans• We are placing unprecedented pressure on marine

resources

– Half the world’s marine fish populations are fully exploited

• Total fisheries catch leveled off after 1998, despite increased fishing effort

– It is predicted that populations of all ocean species we fish for today will collapse by the year 2048

Seafood Watch Video

Fishing has industrialized

• Factory fishing = highly industrialized, huge vessels use powerful technologies to capture fish in huge volumes

• Trawling for pelagic fish and groundfish

• Longlinefishing for tuna and swordfish

• Driftnets for schools of herring, sardines, mackerel, sharks

• Fishing practices kill non-target animals

• By-catch = the accidental capture of animals

– Driftnetting drowns dolphins, turtles, and

seals

– Longline fishing kills turtles, sharks, and albatrosses

– Bottom-trawling destroys communities

• Same level of destruction as clear-cutting and strip mining

Fishing has industrialized We are “fishing down the food chain”

• As fishing increases, the size and age of fish caught decline

– 10-year-old cod, once common, are now rare

• As species become too rare to fish, fleets target other species

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We can protect areas in the ocean

• Marine protected areas (MPAs) = established along the coastlines of

developed countries

– Protect habitat and habitat

– Support fisheries ( young fish are allowed to grow and replenish)

• Many commercial, recreation fishers, and businesses do not support marine reserves

• Levees- an enlarged bank built up on each side of the river.

Altering the Availability of Water

• Dikes- similar to a levee but built to prevent ocean waters from flooding adjacent land.

• Dams- a barrier that runs across a river or stream to control the flow of water.

– World’s Largest= Three Gorges.

– World's largest hydroelectric dam, Three Gorges, Yangtze River

– 1.2 - 1.9 million people displaced

Altering the Availability of Water

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• Fish ladders- a set of stairs with water flowing over them that have been added to some dams to help migrating fish such as salmon get upstream.

• Interruption of natural flow of water to which organisms are adapted.

Altering the Availability of Water

Dams

• Reservoir- the area where water is stored behind the dam.

DamsAdvantages

• No CO2 emissions or other ghgs

• Provides irrigation & drinking water

• Provides flood control

• Cheap electricity

• Reservoir can be used for recreation such as boating

Disadvantages• Displaces people living behind

dams

• Decreases sediment/nutrient flow downstream

• Fish harvest downstream decrease

• Disrupts fish migration patterns

• Loss of water by evaporation

• Loss of some recreation such as fly-fishing, rafting