The Water and Phosphorus Cycles

By:Maren HambyMegan WhitleySebastian Belk Ashley Dolan

The Water Cycle

Water Cycle

• The water cycle, also known as the hydrologic cycle, collects, cleans, and circulates all of the earth’s water supply.

• The water cycle is powered by the sun and by gravity.

Water Cycle

Water Cycle

• Organic reservoirs– Lakes– Rivers– Streams– Oceans– Water tables

• Inorganic reservoirs– Man made dams– Cisterns

Pathway of Movement

• Evaporation: water to water vapor

• Transpiration: evaporation of water from plants

• Condensation: water vapor to water drops

• Precipitation: rain, sleet, hail, and snow

• Infiltration: water soaks into soil

• Percolation: water in soil moves to aquifers

• Runoff: movement back to sea

Impact of Human Intervention On the Water Cycle

• Take water from streams, lakes, oceans, etc.– Underground water depletion– Oceans salts move to underground fresh water

• Modify water quality– Change the processes that purify water naturally– Add nutrients and other pollutants

• like phosphates and nitrates in fertilizers

Impact of Human Intervention On the Water Cycle

• Clear land for mining, road and building construction, agriculture– Increase runoff– Reduces infiltration in ground water– Increase risk of flooding– Increase soil erosion and land slides

Phosphorous Cycle

Pathway of Movement

• Salt phosphates are in water or in rock formations

• Released and absorbed by plants• Animals eat the plants• Animals die and the phosphorous returns

to the ocean and rock formations where it stays for a long time

• Does not circulate through atmosphere• Very slow process

Chemical Reactions

• When absorbed by plants, converted to ATP (adenosine triphosphate) for energy

• When animals eat plants phosphate is incorporated into:– ATP– DNA– Teeth– Bones

Phosphorus Cycle

• Organic reservoirs– Bones– Teeth– ATP– DNA

• Inorganic reservoirs– rocks

Impact of Human Intervention On the Phosphorus Cycle

• Mining phosphate rock for use in inorganic fertilizers and detergents

• Reducing phosphates in forests by removing trees– Phosphorus and other nutrients are washed

away and the land becomes unproductive

Impact of Human Intervention On the Phosphorus Cycle

• Add excess phosphate to aquatic ecosystems through:– Runoff from animal wastes– Runoff of fertilizers from croplands

• Too much can cause explosive growth of:– Cyanobacteria– Algae– Aquatic plants

• When they die and decompose they use up dissolved oxygen and disrupt aquatic life