Biology Ecology (Alberta) 2

Second half of the unit (chapter 3 and 4)

Cycling of matter (digestion)

Complex organic molecules broken down to simple ones

Absorbed into body

Cycling of matter (decay)

Decomposers break down organic matter

Nutrients added to ecosystem

The Value of Water

Absorbs, releases and moderates

thermal energy

▪ Medium for metabolic reactions (metabolism)

▪ Universal solvent

▪ >60% of cell’s mass

▪ Is Polar

▪ Positive and negative ends

▪ Hydrogen bonds

Hydrologic (Water) Cycle steps

Overall water volumes in biosphere are constant, amount in specific phases is variable

Transpiration (Plants releasing water through their leaves)+ Evaporation (water turns to gas) —>

Condensation (gas turns to water) —>Precipitation (the falling of rain)

Sources of Fresh Water (surface)

Precipitation above ground

Sources of fresh water (ground)

Percolation

▪ Water percolates through

larger soil particles

▪ Fills lower levels of soil

▪ Water table above impermeable bedrock/clay

Leaching

Leaching

▪ Seeping H2O carries dissolved organic matter and minerals to lower layers of soil

▪ Plants reduce leaching by extending long branch roots deep into soil

Acid rain (how does it happen)

Plants, refineries, exhaust release sulfur (SO2) and nitrogen oxides (NOx) during combustion

▪ SO2 gas is toxic

Both gasses combine with H2O to form acids

Acid droplets precipitate (acid rain)

Acid rain (What does it affect and how is it combatted)

• Affects fish, soil bacteria, plants, crops. Acid rain leaches heavy metals from soil (mercury) and brings into lakes/rivers

• Alkaline soils minimize impact of acids

• Scrubbers in smoke stacks filter emissions

• Lime added to lakes to neutralize acids

What PH is normal

▪ pH 5.5-5.9 is “normal”

What is an Acid surge?

▪ Short intense acid deposition

▪ Snow melt, heavy rain

▪ 3 reservoirs for inorganic Carbon

▪ Atmosphere

▪ Crust

▪ Ocean

Oceans as a reservoir for inorganic carbon

Gas reacts with H2O and forms inorganic calcium carbonate (CaCO3)

Used for shellfish shells

Huge carbon sink

Organic reservoirs of Carbon

Carbon containing molecules are called Organic molecules, when sourced from living organisms

Includes

1) Bodies of living and dead things

2) Ecosystems

3) Fossil Fuels

Organic reservoirs of Carbon

1) Bodies of living and dead things

Plants (photosynthesis) and Animals

▪ Photosynthesis CO2 + H2O + energy → C6H12O6(glucose) + O2

▪ Cellular Respiration C6H12O6 + O2 → CO2 + H2O + energy (heat and ATP)

Organic reservoirs of carbon 2) Ecosystems

Bogs – Decomposition of peat (plant matter)

▪ Peat is when waterlogged areas lack oxygen and can’t fully decompose organic material, leaving high concentration of organic matter

Organic reservoirs of carbon 3) Fossil Fuels

Carbon from dead organism millions of years ago

Combustion

Climate change

The carbon and oxygen cycle (The oxygen cycle. What is it involved with and apart of?)

Integral part of Photosynthesis and

Cellular Respiration

▪ Oxygen involved with

▪ Ozone (O3)

▪ CO2

▪ Rocks

▪ Decomposition

Human Impact on the Carbon Cycle (The greenhouse effect—natural)

▪ Greenhouse Effect (is natural)

▪ Wavelengths strike Earth’s surface and are reflected

▪ Some of the waves are trapped via atmospheric gas (greenhouse gasses), as a blanket of heat

▪ Canada produces lots of CO2

▪ Greenhouse gasses increased 25% since 19th Century

Human Impact on the Carbon Cycle (Enhanced greenhouse effect)

Enhanced Greenhouse effect

▪ Not natural

▪ Avg global temp is 15oC, increased by 1oC in last 40 years

▪ Melting ice caps could raise sea level by 3 meters

▪ Increased severity in weather events

Human Impact on the Carbon Cycle (albedo affect)

Albedo Effect

▪ Describes extent to which a material can reflect sunlight

▪ Albedo of 0.08 means 8% of light is reflected

▪ Higher albedo, more sunlight reflected, less heat absorbed on Earth

▪ High albedo of snow contributes to low winter temperatures

▪ Cloud cover results in higher albedo

▪ “nuclear winter” involves high albedo cloud coverages

Equilibrium and the Earth’s Atmosphere

▪ “primitive” Earth had high concentration of CO2

▪ 3.5 billion years ago (bya)

▪ Microscopic marine life consumed CO2 and released CH4

▪ Fossils of these bacteria found in stromatolites (banded limestone)

▪ Evidence of warm planet

▪ CO2 and CH4 trapped heat while allowing sunlight to penetrate

▪ Increased temp increased water cycle aggressiveness

▪ Water “grabbed” and absorbed CO2 from the atmosphere, leaving behind CH4

▪ The methane (CH4) haze blocked sunlight, cooling Earth

3.3 The Nitrogen Cycle (the 4 main process)

4 main process

▪ Nitrogen Fixation

▪ Nitrification

▪ Ammonification

▪ Denitrification

▪ Nitrogen(N) makes up 78% of atmosphere, inaccessible to plants and animals in the form

▪ N is important for proteins, DNA and as nitrate ions (NO3- )

Nitrogen Cycle: Nitrogen Fixation

Nitrogen Fixation

▪ N2 is converted to NO3- (Nitrate)

▪ NH4+ ions (Ammonium) also released into the soil

▪ 90% of Nitrogen fixation is performed by nitrogen-fixing bacteria

▪ 10% of nitrogen fixation is the result of lightning

Nitrogen Cycle: Nitrification

▪ Nitrification

▪ NH4+ ions changed to NO3-

▪ Nitrifying bacteria in the soil convert Ammonium (NH4-) to nitrite (NO2-) to nitrate (NO3-)

▪ Most organisms utilize (NO3-) but some can use (NH4-) directly

▪ Nitrates are used for organic functions like proteins

▪ We get our nitrogen from the food we eat

Nitrogen Cycle: Ammonification

▪ Ammonification

▪ Performed by decomposers in the soil

▪ Organic Nitrogen waste and remains are converted into Ammonium (NH4+)

Nitrogen Cycle: Denitrification

▪ Dentification

▪ Denitrifying Bacteria convert NH4+,NO2-, NO3- into free N2 gas.

▪ Returns Nitrogen back to the atmosphere

Phosphorus Cycle

Phosphorus (P) is a component of

▪ Cell membranes

▪ DNA

▪ ATP

▪ Bones

-Phosphate (PO4 3-) is usually found in rock

- Fast track

- Slow track

Agriculture: Nitrogen and Phosphorus Cycles

▪ Fertilizer contains N and P

▪ Manure contains N, used as fertilizer

▪ Commercial Fertilizers

▪ 1st number - % nitrogen by weight

▪ 2nd number - % phosphorus by weight

▪ 3rd number - % potassium by weight

▪ Harvesting crops removes N and P form soil

▪ Disrupts natural cycles

▪ Fertilizing soil restores this disruption

▪ Irresponsible fertilizing makes land acidic

▪ Can lead to Eutrophication

Eutrophication

▪ N and P from fertilized soils is leached out from spring run off

▪ N and P end up into lakes

▪ Promotes aquatic growth

▪ Algae blooms

▪ Algae dies

▪ Bacteria decomposes the massive amounts of algae which depletes oxygen levels

▪ Fish begin to die due to low oxygen