DP Environmental systems and societies

Topic 2

The ecosystem

2.4 BIOMES

BIOME is the collection of ecosystems sharing similar climatic conditions.

Uneven Solar Heating and Latitude

Earth as a whole is in thermal equilibrium, but different latitudes are not. Moving masses of air and ocean currents transport energy from locations with a surplus to those with a deficit.

Cell 3 South

Cold,dry air falls

Moist air rises — rain

Cell 2 South

Cool, dryair falls

Cell 1 South

Moistair rises,cools, andreleasesmoistureas rain

Cell 1 North

Cool, dryair falls

Cell 2 North

Moist air rises — rain

Cell 3 NorthCold,dry airfalls

Polar cap

Arctic tundra

60°

30°

0°

30°

60°

Polar cap

Evergreenconiferous forest

Temperate deciduousforest and grassland

Desert

Tropical deciduous forest

EquatorTropical rain forest

Tropical deciduous forest

DesertTemperate deciduousforest and grassland

Model of global air circulation and biomes.The direction of air flow and the ascent and descent of air masses in convection cells determine the earth’s climatic zones.

MountainIce and snow

Altitude

Tundra (herbs,lichens, mosses)

ConiferousForest

Tropical Forest

DeciduousForest

Tropical Forest

DeciduousForest

ConiferousForest

Tundra (herbs,lichens, mosses)

Polar iceand snow

Latitude

Generalized effects of altitude and latitude on climate and biomes.Parallel changes in vegetation occur when moving from the Equator to the poles or from the lowlands to mountaintops.

DESERT BIOMES

Tropical desert(Saudi Arabia)

Polar desert(northwest China)

GRASSLAND BIOMES

Tropical grassland (savanna)(Harare, Zimbabwe)

Polar grassland (arctic tundra)(Fort Yukon, Alaska)

FOREST BIOMES

Tropical rain forest(Manaus, Brazil) Temperate deciduous forest

(Nashville, Tennessee)

AQUATIC BIOMES

Coral reefsRivers

Lakes Mangroves

Ocean

High tideLow tide

Coastal Zone

EstuarineZone

Continentalshelf

Open SeaSea level

Sun

Euphotic Zone

Bathyal Zone

Abyssal Zone

Depth inmeters

0

50

100

200

Ph

oto

sy

nth

es

is

500

1,000

1,500

2,000

3,000

4,000

5,000

10,000

Da

rkn

es

sTw

ilig

ht

Biomes of the World

1. The Tundra

2. Low biotic diversity

alpine vs arctic tundra

1. Extremely cold climate

3. Simple vegetation structure4. Permafrost limited drainage

5. Short growing season

6. Energy and nutrients in the form of dead organic material

7. Large population oscillations

Biomes of the World2. The Taiga

1. Band of coniferous trees located just south of tundra

aka: boreal forest

2. Milder climate and more diverse biota than tundra

3. Forests subject to heavy logging pressure.

Biomes of the World3. Temperate Rain

Forest

1. Moderate climate and high annual rainfall

2. Relatively nutrient-poor soils3. Forests subject to heavy logging

pressure.

Biomes of the World4. Temperate Deciduous Forest

1. Located in the mid-latitude areas

2. Four distinct seasons

3. Short, cold winters & long, hot, wet summers

4. Trees adapted to the winter with a period of dormancy and thick bark to protect them from the cold weather

Biomes of the World5. Grasslands

1. Composed of a rich mix of grasses and forbs and some of the world's most fertile soils

2. Semiarid, continental climate3. Summers tend to be dry

4. Most precipitation falls at start of growing season

Biomes of the World6. Chaparral (aka: scrub forest)

1. Composed of drought tolerant trees, shrubs, and grasses

2. Occur in California, coastal Mediterranean, and south coast of Australia

3. Plants go dormant during very dry summer

4. Most precipitation falls in winter

Biomes of the World7. Deserts

1. Arid, with annual rainfall less than 10 in.2. Plants adapted to conserve water over long periods (e.g. cacti, sagebrush, and mesquite) or germinate, develop to maturity, flower, and produce a new crop of seeds within a few weeks following a rain event

3. Animals burrow to escape the heat of the desert sun

Biomes of the World8. Savanna

1. Tropical grasslands

2. Tropical climate with alternate wet and dry seasons

3. Characterized by a continuous cover of perennial grasses

Biomes of the World9. Tropical Rain Forests

1. Earth's most complex biome in terms of structure and species diversity

2. Climate characterized by abundant precipitation and year round warmth

3. Trees vertically stratification into three distinct layers

Aquatic EcosystemsTrophic Levels

Aquatic EcosystemsEnvironmental Factors

Temperature

Aquatic EcosystemsEnvironmental Factors

Light

Aquatic EcosystemsEnvironmental Factors

Salinity

Lake Michigan 0.5 PPT

Baltic Sea5-15 PPT

The Dead Sea332 PPT

The Black Sea16 PPT

The Red Sea & The Persian Gulf40 PPT

Pacific Ocean36 PPT

Aquatic EcosystemsEnvironmental Factors

Currents

Aquatic EcosystemsEnvironmental Factors

Dissolved OxygenDissolved Oxygen (mg/L)

Dep

th (

m)

Dep

th (

m)

Temperature (ºC)

DissolvedOxygen

Temperature

Aquatic EcosystemsZonation

Aquatic EcosystemsHuman Impacts

Waterways across the United States are contaminated by a medicine chest of antibiotics, hormones, caffeine, painkillers and other drugs

Agricultural runoff can carry fertilizers, including traces of antibiotics and hormones, into waterways