CHEMICALS IN THE ENVIRONMENT. CHEMICALS CYCLE Earth is a closed system – which means that all atoms on earth remain on earth, including carbon and nitrogen.

CHEMICALS IN THE ENVIRONMENT

CHEMICALS CYCLE

Earth is a closed system – which means that all atoms on earth remain on earth, including carbon and nitrogen.

As organisms grow and eventually die, they use and release certain elements.

These elements are continuously recycled within the environment.

CHEMICALS CYCLE - Carbon

Carbon is the “backbone” of life. Molecules existing as Carbon chains,

such as starches, sugars, proteins, and other compounds make up life as we know it.

Carbon exists in several forms on earth. By understanding the Carbon Cycle, we can understand the importance of carbon.

CARBON CYLE

USES OF CHEMICALS carbon →limestone

Limestone (CaCO3: Calcium Carbonate) is a sedimentary rock composed of the remains of sea organisms such as coral and the shells of mollusks

Has great benefits in agriculture - neutralizing agent for soil and water.

Used as a building material Used by organisms to create essential compounds

such as sugars and proteins Used as a raw material in the production of

cement, glass and iron.

BENEFITS OF CHEMICALS carbon →limestone

USES OF CHEMICALS carbon → carbon dioxide

Essential in photosynthesis

6H2O + 6CO2 ----------> C6H12O6+ 6O2 Used as a refrigerant – Dry Ice Used in fire extinguishers Beverage Carbonation Too much carbon dioxide in the atmosphere, some

believe, is causing global warming

USES OF CHEMICALS carbon → carbonic acid

Carbonic acid is produced when carbon dioxide reacts with water

CO2(gas)+H2O <---> H2CO3 Carbonic acid has been

a factor in the problems associated with acid rain

CHEMICALS CYCLE - Nitrogen

Nitrogen is essential to life as well – it is used to produce proteins and nucleic acids (DNA).

Nitrogen makes up 78% of the earth’s atmosphere, however most organisms are unable to utilize Nitrogen while it is in the atmosphere.

NITROGEN FIXATION

In order to be used by plants, nitrogen must first be converted to a useable form - this is called Nitrogen Fixation

Nitrogen can be “fixed”, or made useable, in several ways1. Biological Fixation - Nitrogen fixing bacteria exist in

the soil and are able to capture Nitrogen from the air and convert it into a form that plants may use.

2. Atmospheric Fixation - Lightning can convert atmospheric nitrogen to a useable form

3. Industrial Fixation - man-made processes can convert nitrogen to useable forms.

CHEMICALS CYCLE - Nitrogen

QuickTime and aﾪSorenson Video 3 decompressorare needed to see this picture.

NITROGEN CYCLE

PROBLEMS WITH NITROGEN

Too much Nitrogen in the environment can be hazardous.

Humans impact the amount of nitrogen by adding fertilizers, and generating industrial emissions.

Too much Nitrogen leads to eutrophication of lakes, acid rain, and health hazards especially to infants.

EUTROPHICATION

Too much Nitrogen (and Phosphorus) builds up in a body of water

This is usually due to runoff of fertilizers and other nitrogen products

The excess Nitrogen promotes algae growth - algal bloom

Bacteria feed on the dead algae. This activity depletes the lake of oxygen which is harmful to life in that body of water.

CITATIONS

Biology: The Science of Life: Ecosystems: The Role of Abiotic Factors. United Learning. 2003.unitedstreaming. 25 June 2007

<http://www.unitedstreaming.com/>