Module 12 and 13

Terrestrial biomes are defined by

dominant plant growth forms

• Terrestrial biome A geographic region

categorized by a particular combination of

average annual temperature, annual

precipitation, and distinctive plant growth forms

on land.

• Aquatic biome An aquatic region

characterized by a particular combination of

salinity, depth, and water flow.

Terrestrial Biomes

Biomes. Biomes are categorized by particular combinations of average

annual temperature and annual precipitation.

Climate diagrams illustrate patterns of

annual temperature and precipitation

Climate diagrams. Climate diagrams display monthly temperature and precipitation

values, which help determine the productivity of a biome.

Terrestrial biomes range from tundra

to tropical forests

There are nine terrestrial biomes:

• Tundra

• Boreal Forest

• Temperate rainforest

• Temperate seasonal forest

• Woodland/shrubland

• Temperate grassland/cold desert

• Tropical rainforest

• Tropical seasonal forest/ savanna

• Subtropical desert

Tundra

• Tundra A cold and treeless biome with low-

growing vegetation.

• In winter, the soil is completely frozen.

• The tundra's growing season is very short,

usually only about 4 months during summer.

• The underlying subsoil, is permafrost.

• Permafrost An impermeable, permanently

frozen layer of soil.

Tundra

Tundra biome. The tundra

is cold and treeless, with

low-growing vegetation.

Boreal Forest

• Boreal forest A forest biome made up primarily

of coniferous evergreen trees that can tolerate

cold winters and short growing seasons.

• Boreal forests are found between about 50˚ and

60˚ N in Europe, Russia and North America.

• This subarctic biome has a very cold climate,

and plant growth is more constrained by

temperature than precipitation.

• The soil is nutrient-poor due to slow

decomposition.

Boreal Forest

Boreal forest biome.

Boreal forests are made

up primarily of coniferous

evergreen trees that can

tolerate cold winters and

short growing seasons.

Temperate Rainforest

• Temperate rainforest A coastal biome typified by

moderate temperatures and high precipitation.

• Coastal biome found along the west coast of North

America from northern California to Alaska, in

southern Chile, on the west coast of New Zealand,

and on the island of Tasmania.

• Ocean currents moderate temperature fluctuations

and provide a source of water vapor.

• Nearly 12-month growing season where winters are

rainy and summers are foggy.

• Mild temperatures and high precipitation support

growth of very large trees.

Temperate Rainforest

Temperate rainforest

biome.

Temperate rainforests

have moderate mean

annual temperatures and

high precipitation that

supports the growth of

very large trees.

Temperate Seasonal Forest

• Temperate seasonal forest A biome with warm

summers and cold winters with over 1 m (39 inches)

of precipitation annually.

• Receives over 1 m (39 inches) of precipitation

annually.

• Found in the eastern United States, Japan, China,

Europe, Chile and eastern Australia.

• Dominated by broadleaf deciduous trees such as

beech, oak and hickory.

• Warmer summer temperatures favor decomposition;

soils generally contain more nutrients than those of

boreal forests.

Temperate Seasonal Forest

Temperate seasonal forest

biome.

Temperate seasonal forest

biomes have moderate

mean annual temperatures

and moderate amounts of

precipitation that support

broadleaf deciduous trees

such as beech, maple, oak,

and hickory.

Woodland/Shrubland

• Woodland/shrubland A biome characterized

by hot, dry summers and mild, rainy winters.

• Found on the coast of southern California,

southern Australia, southern Africa and in the

area surrounding the Mediterranean Sea.

• There is a 12-month growing season, but plant

growth is constrained by low precipitation in

summer and by relatively low temperatures in

winter.

• Wildfires are common and plants of this biome

are well adapted to both fire and drought.

Woodland/Shrubland

Woodland/shrubland biome.

The woodland/shrubland biome is

characterized by hot, dry summers

and mild, rainy winters.

Temperate Grassland/Cold Desert

• Temperate grassland/cold desert A biome

characterized by cold, harsh winters, and hot, dry

summers.

• Lowest average annual precipitation of any temperate

biome.

• Found in the Great Plains of North America, in South

America, and in central Asia and eastern Europe.

• Plant growth constrained by both insufficient

precipitation in summer and cold temperatures in

winter.

• Plants include grasses and non woody flowering

plants well-adapted to wildfires and frequent grazing

by animals.

Temperate Grassland/Cold Desert

Temperate grassland/cold

desert biome.

The temperate grassland/cold

desert biome has cold, harsh

winters and hot, dry, summers

that support grasses and

nonwoody flowering plants.

Tropical Rainforest

• Tropical rainforest A warm and wet biome found

between 20° N and 20° S of the equator, with little

seasonal temperature variation and high precipitation.

• Average annual temperatures exceed 20˚C.

• Found in Central and South America, Africa,

Southeast Asia, and northeastern Australia.

• Precipitation occurs frequently; warm and wet with

little temperature variation.

• Contain more biodiversity per hectare than any other

terrestrial biome; contain up to two-thirds of Earth's

terrestrial species.

Tropical Rainforest

Tropical rainforest biome.

Tropical rainforests

are warm and wet, with little

seasonal temperature

variation. These forests are

highly productive with several

distinctive layers of

vegetation.

Tropical Seasonal Forest/ Savanna

• Tropical seasonal forest/savanna A biome marked

by warm temperatures and distinct wet and dry

seasons.

• Tropical seasonal forests are common in much of

Central America, on the Atlantic coast of South

America, in southern Asia, in northwestern Australia,

and in sub-Saharan Africa.

• Soil in this biome is fairly fertile and can be farmed

due to high decomposition rates, but the low amount

of precipitation constrains plants from using the soil

nutrients that are released.

• Grasses and scattered deciduous trees are common.

Tropical Seasonal Forest/ Savanna

Tropical seasonal

forest/savanna biome.

Tropical seasonal forest and

savannas have warm

temperatures and distinct wet

and dry seasons. Vegetation

ranges from dense stands of

shrubs and trees to relatively

open landscapes dominated

by grasses and scattered

deciduous trees.

Subtropical Desert

• Subtropical desert A biome prevailing at

approximately 30° N and 30° S, with hot

temperatures, extremely dry conditions, and

sparse vegetation.

• The Mojave Desert in the southwestern United

States, the Sahara in Africa, the Arabian Desert

of the Middle East and the Great Victoria Desert

of Australia are all subtropical deserts.

• Cacti, euphorbs and succulent plants are well

adapted to this biome.

Subtropical Desert

Subtropical desert biome.

Subtropical deserts have hot

temperatures, extremely dry

conditions, and sparse

vegetation.

Module 13

Aquatic Biomes

After reading this module you should be able to

• identify the major freshwater biomes.

• identify the major marine biomes.

Freshwater biomes have low salinity

Freshwater biomes include:

• Streams and rivers

• Lakes and ponds

• Freshwater wetlands

Streams and Rivers

• Flowing fresh water that may originate from

underground springs or as runoff from rain or

melting snow.

• Streams are typically narrow and carry relatively

small amounts of water where rivers are usually

wider and carry larger amounts of water.

Lakes and Ponds

• Lakes and ponds contain standing water, at least some of

which is too deep to support emergent vegetation.

• Lakes are larger than ponds but there is no clear point at

which a pond is considered large enough to be called a lake.

• Littoral zone The shallow zone of soil and water in lakes and

ponds where most algae and emergent plants grow.

• Limnetic zone A zone of open water in lakes and ponds.

• Phytoplankton Floating algae.

• Profundal zone A region of water where sunlight does not

reach, below the limnetic zone in very deep lakes.

• Benthic zone The muddy bottom of a lake, pond, or ocean.

Lakes and Ponds

Lake zones. The littoral

zone consists of shallow

water with emerging, rooted

plants whereas the limnetic

zone is the deeper water

where plants do not

emerge. The deepest water,

where oxygen can be

limiting because little

sunlight penetrates to allow

photosynthesis by

producers, is the profundal

zone. The sediments

that lie beneath the littoral,

limnetic, and profundal

zones constitute the benthic

zone.

Lakes and Ponds

Lakes are classified by their level of primary

productivity.

• Oligotrophic Describes a lake with a low level

of productivity.

• Mesotrophic Describes a lake with a moderate

level of productivity.

• Eutrophic Describes a lake with a high level of

productivity.

Freshwater Wetlands

• Freshwater wetlands An aquatic biome that is

submerged or saturated by water for at least

part of each year, but shallow enough to support

emergent vegetation.

• Freshwater wetlands are among the most

productive biomes on Earth.

Marine biomes have high salinity

There are five marine biomes:

• Salt marsh

• Mangrove swamp

• Intertidal zone

• Coral reefs

• Open ocean

Salt Marsh

• Salt marsh A marsh containing nonwoody

emergent vegetation, found along the coast in

temperate climates.

• Found along the coast in temperate climates.

• The salt marsh is one of the most productive

biomes in the world.

Mangrove Swamp

• Mangrove swamp A swamp that occurs along

tropical and subtropical coasts, and contains

salt tolerant trees with roots submerged in

water.

• Mangrove trees are salt tolerant and help

protect the coastlines from erosion and storm

damage.

Intertidal Zone

• Intertidal zone The narrow band of coastline

between the levels of high tide and low tide.

• Waves that crash onto the shore in this biome

can make it a challenge for organisms to hold

on and not get washed away.

Coral Reefs

• Coral reef The most diverse marine biome on

Earth, found in warm, shallow waters beyond

the shoreline.

• Earth's most diverse marine biome even though

coral reefs are found in water that is relatively

poor in nutrients and food.

• Coral bleaching A phenomenon in which algae

inside corals die, causing the corals to turn

white.

Open Ocean

• Open ocean Deep ocean water, located away

from the shoreline where sunlight can no longer

reach the ocean bottom.

• Photic zone The upper layer of ocean water in

the ocean that receives enough sunlight for

photosynthesis.

• Aphotic zone The deeper layer of ocean water

that lacks sufficient sunlight for photosynthesis.

• Chemosynthesis A process used by some

bacteria in the ocean to generate energy with

methane and hydrogen sulfide.

Open Ocean

The open ocean. The open ocean can be separated into several distinct zones.