Terrestrial and Aquatic Biomes

How many terrestrial biomes are there?

9

What are the 3 temperature ranges?

< 5 degrees C

5 degrees C - 20 degrees C

> 20 degrees C

In climate diagrams, when is plant growth constrained by temperature?

When the temperature line goes below the precipitation line

Describe tundras

Coldest biome

Treeless expanse above permafrost

Precipitation is < 600 mm

Soils are acidic and nutrient-poor

Plants grow low to the ground to gain protection under snow and ice

Describe Boreal Forests

Densely populated by evergreen needle-leaved trees

Short growing season

Severe winters

Temperatures are < 5 degrees C

Precipitation is 50 - 1,000 mm

Soils are acidic and podsolized

Species diversity is low

Describe Temperate Rainforests

Mild temperatures

Abundant precipitation

Dominated by evergreen forests

Warmer conditions due to nearby warm ocean currents

Typically support low species diversity

Describe Temperate Seasonal Rainforests

Moderate temperature and precipitation conditions

Dominated by deciduous trees

Conditions fluctuate

Precipitation exceeds transpiration

Soils are podsolized, slightly acidic, and support a layer of small plants beneath the dominant trees

Describe Woodlands/Shrublands

Hot, dry summers

Mild, wet winters

12-month growing season

Frequent fires

Dominated by schlerophyllous vegetation

Describe Temperate Grasslands/Cold Deserts

Hot, dry summers

Cold winters

Dominated by grasses, non-woody flowering plants, and drought-adapted shrubs

Soils are low in acidity and nutrient-rich with lots of organic matter

When do tallgrass prairies occur?

When rainfall is high

Where do shortgrass praires occur?

In areas with less precipitation

Describe Tropical Rainforests

Warm and rainy

Multiple layers of lush vegetation

Canopy of 30-40 m trees

Highest species diversity

Organic matter decomposes quickly

Soils are devoid of humus and clay, and retain nutrients very poorly

Describe Tropical Seasonal Forests/Savannas

Warm temperatures

Pronounced wet and dry areas

Dominated by deciduous trees

Long dry periods

Contain grasses and occasional trees

Fire and grazing maintain savannas

Soils do not hold nutrients

Warm climate favors rapid decomposition and fast growth

Describe Subtropical Deserts

Hot temperatures

Scarce rainfall

Long growing seasons

Sparse vegetation

Shallow soils that are devoid of organic matter and have a neutral pH

Describe Streams

Support fewer species than other aquatic biomes

Shaded

Nutrient poor

What is most of the organic matter in streams?

Allochthonous

What is most of the organic matter in rivers?

Autochthonous

What are dams built for?

Control flooding

Provide water for irrigation

Generate electricity

What are the results of dam?

Waters behind the dams often become warmer

Stream bottoms become filled with silt

Water released from dams contain low oxygen concentrations

Alter seasonal cycles of flooding

Disrupt the natural movement of aquatic organisms upstream and downstream

Where does most of production occur in ponds and lakes?

In the epilimnion because it is well-aerated

Why does the hypolimnion layer contain anaerobic conditions?

Lack of light and high rates of bacteria-driven organic matter decomposition

What are the different freshwater wetlands?

Swamps

Marshes

Bogs

Describe Swamps

Contain emergent trees

Describe Marshes

Contain emergent non-woody vegetation

Describe Bogs

Contain acidic water and plants adapted to these conditions

Where are salt marshes often found?

At continental coasts

In estuaries

Describe Estuaries

Contain abundant nutrients and sediments carried downstream by rivers

Support extremely high biological productivity

Often surrounded by tidal marshes

What do mangrove trees do in their environments?

Prevent the erosion of shorelines from incoming waves

Provide habitat for many species of fish and shellfish

Describe the water of intertidal zones

Widely fluctuating temperatures and salt concentrations