Biogeochemical Cycles: Ecosystem Recycling

• Energy and chemical compounds flow through the ecosystem

• WATER—NITROGEN—CARBON—PHOSPHORUS are RECYCLED!!!

• They move through a BIOGEOCHEMICAL CYCLE:

• They move from the ABIOTIC (non-living) parts of the environment (like the atmosphere) LIVING THINGS (BIOTIC) THEN BACK AGAIN

Water Cycle

Water Cycle • Cells contain 70-90% water (H2O)

• Most of Earth’s water is in the oceans (~97%) so it is unavailable to living things

• Water in the atmosphere= WATER VAPOR

• GROUND WATER = water that is in the soil or stored underground

• WATER CYCLE = movement of water between reservoirs, includes:

– EVAPORATION

– TRANSPIRATION

– PRECIPITATION

Evaporation

• ADDS H20 VAPOR TO ATMOSPHERE

• HEAT CAUSES WATER TO EVAPORATE

Transpiration

• Plants take in water though their roots

• Plants often release water when they absorb carbon dioxide from the air. The released water is the process of transpiration

Precipitation• Precipitation is when water

leaves the atmosphere

• Temperature & air pressure (ABIOTIC FACTORS) determine how much water can be stored in the atmosphere

• Once the atmosphere can’t store any more water, we have precipitation=

– SNOW, RAIN, SLEET, HAIL OR FOG

Carbon Cycle

The Carbon Cycle

• Carbon is important because all life on earth is based on carbon.

Carbon Cycle• The carbon cycle is the movement of carbon

through the living and non-living parts of the ecosystem

• The primary parts of the carbon cycle are: PHOTOSYNTHESIS + CELLULAR RESPIRATION

Photosynthesis• PHOTOSYNTHESIS = when plants and other

autotrophs use carbon dioxide in the atmosphere, water, and energy from sunlight to produce oxygen and glucose (a carbohydrate)

CELLULAR RESPIRATION

• The process in which all living things use oxygen (O2) to breakdown carbohydrates and release energy (ATP)

Photosynthesis vs. Cell Respiration

CO2 O2

Decomposition

• Decaying plants, animals, and waste decompose after millions of years and turn into fossil fuels.

HUMAN INFLUENCE ON

THE CARBON CYCLE

• In the past 150 years, the amount of carbon dioxide (CO2) in the atmosphere has risen quickly (as you can see in the graph)

• The cause of this sudden increase is human activity, mostly burning fossil fuels to use for energy

• Remember that FOSSIL FUELS:

– REMAINS OF ORGANISMS THAT HAVE BEEN TRANSFORMED BY DECAY, HEAT, & PRESSURE ENERGY RICH ORGANIC MOLECULES

Burning fossil fuels releases carbon dioxide that goes into the atmosphere

Human Impact on the Carbon Cycle (continued)

• Burning fossil fuels releases energy and carbon dioxide

• Burning vegetation (plants, forests, etc.) also releases CO2.

• Destroying forests (deforestation) and plants also stops the plants from absorbing carbon dioxide in the atmosphere.

• The extra carbon dioxide in the atmosphere then traps heat from the Sun, which causes the Earth’s temperature to increase, a process known as Global Warming.

Nitrogen Cycle

The Nitrogen Cycle

• The nitrogen cycle shows how nitrogen is recycled throughout the environment.

Nitrogen Cycle• Nitrogen is needed to produce amino acids (proteins) and

nucleotides (nucleic acids).

• These two important organic molecules form the structure of our cells and carry genetic information for the cell

• N2 (nitrogen gas) makes up 78% of the Earth’s atmosphere

• Unfortunately, we can’t directly use the nitrogen in the atmosphere, it needs to be “fixed” for our use

The Nitrogen Cycle

• Nitrogen gas (N2) must be broken down by lightning, fire, or bacteria before plants & animals can use it.

NITROGEN FIXATION

• Nitrogen fixation is the conversion of nitrogen gas (N2) into Ammonia

• This process can only be performed by certain types of bacteria, called Nitrogen Fixing Bacteria.

• These bacteria can live in the soil or theroots of plants.

The Nitrogen Cycle

• Animals get nitrogen by eatingplants.

• All nitrogen obtained by animals can be traced back to the eating of plants at some stage of the food chain.

Recycling Nitrogen

• Bodies of dead organisms contain Nitrogen, so does urine and other waste

• DECOMPOSERS break down dead organisms and remove that nitrogen