The BiosphereChapter 8

What is the Biosphere?

• Lithosphere – solid layer

• Hydrosphere – the water layer

• Atmosphere – layer of air

• Biosphere – layer of life!!!

• The layers overlap each other

• The is the layer around the Earth that contains all living things.

2 – Biochemical cycles

• A biochemical cycle is a set of processes by which an elements passes from one environment to the next and eventually return to its original environment, in an infinite loop of recycling.

Respiration (animals) photosynthesis (plants)

2.1 – The Carbon Cycle

• Carbon is the basic element in complex molecules that make up living organisms.

• Protein, lipids, carbohydrates

• Carbon dioxide (CO2) and methane (CH4) are two gases that contain carbon that are present in the atmosphere.

• The carbon cycle is a biogeochemical cycle involving all the exchanges of carbon on Earth.

• Human activities have upset the carbon cycle.

– Started with the industrial revolution

– Burning fossil fuels!!!

– Methane is released from the decomposition of human waste!!

2.2 - The Nitrogen Cycle

• Living things need nitrogen

– DNA!!!

• Bacteria fix atmospheric nitrogen into forms that living organisms can use

– NH3 and NH4

– Occurs in both the lithosphere and the hydrosphere.

• The nitrogen cycle is a biogeochemical cycle involving all the exchanges of nitrogen on Earth.

2.3 - Phosphorus Cycle

• The phosphorus cycle is the biogeochemical cycle involving all the exchanges of phosphorus on Earth.

• Phosphorus is essential to life; as are C and N.

• Important component of DNA

• Important for the formation of bones, shells and teeth.

• Human activities have also destabilized this system.

– Heavy use of fertilizers, soap residue etc.

– Excess P in water causes eutrophication

– The oxygen concentration falls very low is deep water because of excessive nutrients.

– Animals cannot live in eutrophicated water!!!!

3 - Biomes

• Biomes are large regions of the world with distinctive climates, wildlife and vegetation

• There are terrestrial biomes and aquatic biomes

• The factors that determine a biome are shown in Table 8.5 on page 262

• These factors deterine which plants and animals can exist in certain biomes

Terrestrial Biomes Aquatic Biomes

Latitude Salinity

Altitude Turbidity (water clarity)

Temperature Temperature

Precipitation Direction and strength of current

Soil Type Presence of oxygen and carbon dioxide for respiration and photosynthesis

Solar energy – exposure to sunlight

Solar energy

Wind Nutrients (types)

Proximity to bodies of water Water depth

3.2 – Terrestrial Biomes • Temperature and precipitation are the two

factors that affect terrestrial biomes the most.

– These affect plant species which then affect animal species

• We will look at seven biomes:1. Tropical forest 5. Arctic Tundra

2. Boreal forest 6. Dessert

3. Temperate forest 7. Alpine biomes

4. Grassland and shrublands

Tropical Forests

• Found on either side of the equator

• Between the Tropic of Cancer and the Tropic of Capricorn

• Temperature various between 20 and 34 degrees Celcius

• Great biodiversity!!!• Help regulate the world’s

climate

Boreal Forest

• More than 25% of the world’s forest !!

• Cover most of Canada!!

• Composed mostly of conifer trees

• Diverse animals live here

• Source of timber

Temperate Forest

• Found in southern Canada, the U.S. and Europe

• Quebec’s temperate forest includes a mix of coniferous and deciduous trees

• Further south it is made mainly of deciduous trees

• Large portions have been destroyed and the land is used for farming.

Grasslands and Shrublands

• Can handle fire, drought, and mowing

• The roots of grasses are well developed!!

• Three main types:

1. Temperate grasslands

2. Savanna

3. Derived grasslands

Grasslands and Shrublands

• Can handle fire, drought, and mowing

• The roots of grasses are well developed!!

• Three main types:

1. Temperate grasslands

2. Savanna

3. Derived grasslands

Temperate grasslands

• Summers are hot and winters are long and cold

Savannas

• Tropical or subtropical grasslands where it is hot all year long

Derived grasslands

• “Artificial fields” of grass and grain that are replacing natural grasslands.

• 90% of the prairies are now artificial grasslands

Arctic Tundra

• North of the boreal forest

• Forms a ring of vegetation around the North Pole

• Covers 6% of the world’s surface

• Permafrost is found here

• Short growing season

• Many migratory animals!!

Desert

• Cover 1/3 of the Earth’s land mass

• Less than 25 cm of precipitation

• Very high or very low temperatures

• Rare plant life

• Only a few animals

Alpine Biome

• Defined by altitude rather than latitude

• Rocky Mountains, the Andes and the Himalayans

• Sub-mountain zone below 1300m.

• Montane zone between 1300 and 1800 m.

• Sub-alpine zone between 1800 and 2400 m.

• Alpine zone 2400 m and up.

• Nival zone - more than 3000m.

3.3 – Aquatic Biomes

• Approximately 75% of the Earth is covered in water.

– Freshwater 2.5% (<0.05% salt)

– Marine 97.5% (>3% salt)

• What are Quebec’s aquatic biomes?

Freshwater Biomes

Lakes

• Bodies of water surrounded by land and fed by streams, river or precipitation

• Quebec has more than half a millions acres of lakes!!!!

• The organism are in an interrelated system and together they make it balanced.

• Watersheds are the areas where water drains from to the lakes, rivers, and streams.

Rivers

• Streams and rivers form a permanent or seasonal drainage channels for surface water.

• Plants and animals must be adapted to the moving water.

• Water quality has been negatively affected by agricultural and industrial practices.

Wetlands• Areas permanently or temporarily covered in

water• The plants found here grow in water

saturated soil.• Maybe fresh or salt waterThree different types of wetlands:1. Marshes – land covered with stagnant water

and without trees2. Swamps – land covered with stagnant or

slow moving water in which trees and shrubs grow

3. Peat bogs – Poorly drained soil covered with moss

• 9% of Quebec and 14 % of Canada is covered in wetlands

• There are millions of prairie potholes!!!

• Habitat for many plants and animals.

• Absorb water and prevent flooding and help clean the water.

• 90% of the wetlands in rural quebec have been destroyed

Marine Biome

• Saltwater environments

• Unit estuaries, oceans, seas, and coral reefs

• Vary in temperature, chemical composition and depth

Estuaries

• Where the mouth of a river broadens and empties into the sea/ocean.

• The mixing zone between freshwater and marine environments

• Sediment builds up when the river water meets the ocean

• The St Lawrence Estuary runs from TroisRivieres to Point des Monts.

Oceans and seas

• Wide variety of living conditions!!!

• Marine habitats are subdivided by depth (3800m!!)

• Sunlight does not penetrate more than 200m

• Free living creatures and benthic creature (live in of on the sea bed)

• Most bottom dwellers are found within 350 km of the shore

• 80% of fishing activity is done near the coast

Coral Reefs

• Very bio-diverse.

• Most are found in the tropics

• Corals form colonies of thousands of individuals

• The coral produces calcium carbonate which makes the reef.

• 20% of coral reefs have been destroyed by pollution, overfishing, global warming and increased human activity