Environmental Science Section 2: Biomes

what are biomes?

Major regions of differing vegetation and whildlife types

What are the 2 most important factors controlling the fomation and distibution of biomes? Why?

Global patterns of temperature and precipitation/moisture as they influence the amount of energy available in differing regions of the world

What are global patterns of temperature and precipitation influenced by?

Global air and water circulation

What is solar energy flux

The amount of the Sun's energy hitting different pats of the Earth

What does solar energy flux influence?

Global atmospheric ciculation which in turn drives global oceanic ciculation

How many hous a day does pats of the Earth receive?

12 hours a day.

Hadley cell

Air in the equator is heated the most by the sun and rises the most, cooler ai from both north and south moves in to replace, and the warm air cools as it rises (condensing and losing its moisture) and descends around 30 degrees both north and south.

Where are most deserts?

30 north and south degrees

What are seasons caused by?

The Earth's tilt

What is the Coriolis effect

North air masses move towards the right and South air masses move towards the left

Air direction is _______ in the north and ______ in the south

clockwise in the North and counterclockwise in the South

What are general patterns of wind modified by?

Land masses that split and redirect flow

Why are places like Anchorage, Alaska and Iceland not nearly as cold as their latitude would suggest?

Because they draw heat from moving waters form the equator towards the poles.

Tropical Rainforest(evergreen)

1. Warmest and Wettest

2. Amazon and in western and central Africa

3. High plant and animal diversity

4. High productivity, but most energy is in vegetation, so poor soil

Tropical dry (seasonal) forest

1. Some tropical forests experience a dry season

2. Deciduous trees, which drop their leaves and flowerrs during the dry season.

3. Productivity is less than tropical rainforests

Temperate rainforest

1. US Pacific Northwest

2. Tall, coniferous trees 60-70 m high

3. Mild winters, heavy rain and frequent fog

4. Rich soils

5. Productivity is 1/2 of tropical rainforests

Temperate broadleaf forest

1. Moderate rainfall and high seasonal temperature variation

2. Productivity like Temperate rainforests

3. Deciduous-dominated

4. East US, Southern Canada, Europe and eastern Asia

5. Rich soil because leaf litter

Boreal conifeous forest

1. Moderate to high rainfall

2. Spruces and firs 10-20 m high

3. Mammals like moose, bear, wolf and Siberian tiger

4. Productivity is 1/3 that of tropical rainforests

5.Yearly weather variation leads to yearly variation in seed production which causes fluctuations in animal populations

6. Low temperatures and chemicals in foliage result in low leaf litter decomposition and poor soils

Temperate grassland

1. Too little precipitation for dense forests

2. called prairies in the US and steppes in Asia

3. 1/3 of tropical rainforest productivity

4. Rich land

Savana/ Tropical Scrub Forest

1. 10-150 cm/year and is seasonal, during driest 3-4 months of the year, less than 5 cm per month

2. Most common in dry tropical regions of Africa

3. Scrub vegetation

4. Migrating herbivores

5. Fire and grazing necessary to maintain this biome

Mediterranean

1. Known as chaparral in CA

2. Receives most of their rain in winter, before temperatures rise enough to permit plant growth.

3. Mostly dense, woody shrubs and small trees with leathery and waxy leaves to retain water.

4. Frequent fires, many trees are now fire-resistant

5. Jackrabbits, kangaroo rats, chipmunks, mule deer and several species of lizards.

Desert

1. Less than 25 cm of rain

2. Mongolia and Montana and Antarctica: cold deserts

3. Sparse shrubs and grass

4. Sandy or rocky soil

5. 0-5 % of tropical rainforest productivity

Tundra

1. Arctic beyond the tree line, the upper limit of tree growth at high latitude or elevation

2. grasses and grass-like sedges, lichens and dwarf form of trees.

3. Permafrost all year round, but thaws a out 0.5m to 1 meters during the summer growing season

4. Rodents lemmingsabundant but fluctuates with variation in resources, and birds migrate south during the winters.

5. 5-10% of productivity of the tropical rainforests.

Why do aquatic regions not hhave biomes?

Because they don't have the variety of plants characteristic of terrestrial biomes

What are the types of aquatic systems?

Freshwater and Marine

What can freshwater systems be further subdivided into?

Flowing and standing waters

What is the benthic community?

Community on the floor of the body of water

What is the major eneergy producer of lakes and ponds?

Phytoplankton (algae)

What are zooplankton?

Small animals, mostly crustaceans.

What are thermoclines?

thermally separated layres in a body of water due to abrupt changes in the temperature of the water

What is the breaking level of photosynthesis in oceans?

100-200 meters

What percent of Earth is the ocean?

71 percent

What community does not need light?

The volcanic vent commuity

What is the limiting factor of surface level water?

Surface level water is low in nutrient content

What depth is the peak species diversity in oceans and exceptions?

2000-3000 m...exceptions are oceans with major upwellings (wind washes the water away so nutrient rich water can rise up) and places near coast (nutrients from land (where fisheries fish))

What are the transitional regions between terrestrial and aquatic?

Salt marshes, bogs and swamps, and intertidal areas.

What are the 3 types of wetlands?

1. Marine wetland (intertidal)

2. Estuarine wetland (mouth)

3. Freshwater wetlands

What wetland makes up how much of US wetlands?

Freshwater, 91%

What are freshwater wetlands?

Bogs, marshes, swamps, peatlands, less than 2 m deep.

What are considered the building blocks of life?

Carbon, Hydrogen, Oxygen

What are the macronutrients? (6)

1. Sulfur

2. Potassium

3. Phosphorus

4. Nitrogen

5. Magnesium

6. Calcium

Why are they called macronutrients?

Because they are required in relatively large amounts: usually over 0.1 % of an organism's dry weight

What are the plant-essential micronutrients?

1. Manganese

2. Iron

3. Copper

4. Zinc

5. Chloride

6. Molybdenum

7. Boron

What is considered the "original source" of elements?

The atmosphere and the rocks (but the soil is an intermediary for most plants)

What is the main energy source for the hydrologic cycle?

The Sun

What are the MRTs for the reservoirs of the hydrologic cycle?

MRT for ocean : 2650 years

MRT for terrestrial water: 403 years

MRT for atmosphere : 8 days

What is carbon fixation?

It is the initial incorporation of CO2 into organic material.

What other process is respiration similar to?

Combustion

What is the greatest amount of carbon on Earth?

Tied up in Carbonate rock like limestone and organic matter in sedimentary rocks such as shale

Does the abiotic pool of rocks carbon cycle quickly?

No

After rocks ,where is the next largest pool of carbon, and how quickly does it cycle?

Oceans, not very quickly

The oceans are becoming more ______ because of

acidic because of the increase in CO2 in the atmosphere

What is slash and burn agriculture?

burning plains for fertile soil and cleared area

What is the lithosphere>

crust and upper mantle

Why is nitrogen critical for life on Earth?

Because it is one of the elements in amino acids

Why is nitrogen important?

It is in amino acids

How much of the atmosphere is nitrogen?

78%

For most land plants, what is the limiting element?

Nitrogen

Which of the macronutrients does plants require the most of?

Nitrogen

What types of organisms can use the dominant form of nitrogen, N2?

Nitrogen fixation-capable organisms

In nitrogen fixation, what happens?

N2 to NH4+ or ammonium.

What is capable of nitrogen fixation?

Cyanobacteria, certain bacteria and fungi associated with legumes, like peas and trees such as alders

How is atmospheric nitrogen fixed apart from ammonium?

Fixed by lightning and combustion into nitrate anion, which is stored by the plant. When the plant dies this turns into ammonium cation via bacteria

What is the turning of organic matter to ammonium called?

Ammonification

What is nitrification

Ammonium into nitrate (with nitrite as an intermediate step)

What is nitrite toxic to?

Infants

What is nitrate susceptible to?

Leaching

When a lot of nitrate leaches, what happens?

Denitrification. It gets turned into nitrous oxide, which is emitted.