Ecology Part 2 ( Cycles of Matter)

Biogeochemical Cycles

• Matter can neither be created or destroyed

• Cycle of transferring nutrients from the environment, to an organism, and back to the environment

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  Remember - Energy Pathways

• Energy enters an ecosystem in the form of sunlight

  • Eventually all energy is lost as heat

  • Biosphere requires a continual flow of new energy

Nutrient Cycling

• On Earth there is finite supply of nutrients

• To maintain balance, matter is recycled

Main elements that are recycled: Carbon, Hydrogen, Oxygen, Nitrogen

The Cycles

• Hydrologic Cycle or Water Cycle

• Carbon/Oxygen Cycle

• Nitrogen Cycle

• Phosphorus Cycle

Hydrologic Cycle/Water Cycle

path of water through the environment

The Water Molecule

Polarity:

The attraction of water molecules. One end of the molecule is positive, and otherend is negative.

Polarity Results in Hydrogen Bonding

Hydrogen Bonding

Attraction between slightly negative O and slightly positive H

Hydrogen bonds require energy to break:

• This is what allows water to gain and storelarge amounts of energy

• This also gives water a high boiling and freezing points.

Hydrologic Cycle – Abiotic/Biotic Components

Abiotic: Precipitation, Groundwater, Evaporation, Condensation

Biotic: Cellular Respiration

The Cycling of Water

Moves from atmosphere to earth through precipitation. Surface runoff and groundwater flows to other bodies of water.

Water enters the atmosphere through transpiration and evaporation

Acid Deposition

Sulfur dioxide and nitrogen oxides can condense with water vapor in the air to form tiny droplets of acid.

This is called acid rain.

Carbon/Oxygen Cycle

The flow of CO2 through the biosphere.

The main part of this cycle involves the relation between respiration and photosynthesis.

Enhanced Greenhouse Effect

CO2 in the atmosphere traps heat where it is re-emitted to the ground.

Other greenhouse gasses:

Water vapour (H2O)

Methane (CH4)

Nitrous oxides

Chlorofluorocarbons (CFCs) ,

Nitrogen Cycle

The complex cycling of nitrogen between organisms and the environment.

Nitrogen in the atmosphere is N2 gas. Organisms need nitrogen in the form of nitrates or nitrites to grow.

Nitrogen Use

There are 2 main ways atmospheric nitrogen can be converted into useful forms.

Lightning: Lightning can force nitrogen and oxygen together to form nitrates then plants turn it into proteins

Legumes: Legumes have nitrogen fixing nodules on their roots that can convert atmospheric nitrogen into nitrates. Called Nitrogen Fixation or nitrification.

Ammonification

After an organism dies, it decays. Decaying matter which contains nitrogen produces ammonia. Ammonia will degrade into nitrites then will turn into nitrates then those will re enter the cycle

Denitrification

Some bacteria convert the nitrates back into atmospheric nitrogen.

Denitrifying bacteria. NO3- 🡪 NO2- 🡪 N2

Phosphorous Cycle

Phosphorus is a nutrient required by all living things.

Long term cycle: Phosphorous in rocks dissolved in water and carried from land to the ocean then turned into sediments that may be thrusted upwards once again to form new land

Short term cycle: phospahates in water enter food chain through plants. Plants are eaten by animals. Decomposition of dead organisms put phosphates back into the soil