ECOSYSTEM RECYCLING

Material Cycles

As energy & matter move through ecosystem matter must be recycle and reused

Types of Cycle1. Carbon & Oxygen Cycles2. Water Cycle3. Nitrogen Cycle

Carbon & Oxygen cycle

Involves the process of photosynthesis & respiration Photosynthesis uses CO2 and produces O2

Respiration use O2 and produces CO2

 Different meanings of the word respiration1. Cellular Respiration (carbon cycle talks about

this) All living things do this

2. Breathing with lungs and mouth (only some do this)

The carbon cycle is one of the most important to humans because it is important to our existence:  One of the major elements forming human

tissues  Necessary to plants, the basis of human food  Important to the climate system which sets the

background for our environment:  Carbon dioxide (CO 2 ) and methane (CH 4 ) are

greenhouse gases which help set global temperatures

Human influences on carbon cycle

In last 150 years atmospheric CO2 has risen 30%

This is caused by burning fossil fuels Factories and cars

Also by burning forests (to clear land for agriculture) Now less vegetation is available to absorb

CO2 from atmosphere through photosynthesis

The burning also releases more CO2

Increased levels CO2 is causing global climate change

Water Cycle

Availability of water is one of the key factors that determine the productivity of a terrestrial/land ecosystem

Water is found in bodies of water, atmosphere, the ground and living organisms

InvolvesPhotosynthesis & Respiration Transpiration (movement of water through a

plant)Evaporation & CondensationExcretion

Heat causes water to EVAPORATE from bodies of water, soil and organisms TRANSPIRATION

is when water evaporates from plants

Water leaves the atmosphere through PRECIPITATION

Nitrogen Cycle

Organisms need nitrogen to make amino acids, proteins and nucleic acids. The nitrogen gas in the air is in a form that is not usable!

Nitrogen fixing bacteria—transform nitrogen gas into a usable form Live in soil and inside swellings on roots of

certain plants (mutualism)Involves decomposers and other soil bacteria which

break down and convert nitrogenous (urine) wastes and the remains of dead organisms into material that is usable by autotrophs (nitrates)

Another type of bacteria will return nitrogen gas to atmosphere (denitrification)