Phosphorus Cycle Evan, Laetitia, Nikki, and Sabrina

Define nutrients, stores and cycles  Nutrients: chemicals that are required by plants and animals for growth and other life processes.  Stores: areas where nutrients accumulate for short or long periods of time. Also known as sinks. Nutrients are accumulated for short or long periods of time in earth’s atmosphere, ocean and landmasses. Biotic processes, such as decomposition and abiotic processes, such as river run – off can cause nutrients to flow in and out of stores.  Nutrient cycles: continuous flow of nutrients in and out of stores (sinks). Also known as exchanges. Nutrient cycles are nearly in balance; the amount of nutrients flowing into the stores is nearly the same as the amounts flowing out of the stores.

How have humans impacted the Phosphorus Cycle?  Human activities such as land clearing, agriculture, urban expansion, mining, motorized transportation, either add or reduce excess phosphorus supplies in the ecosystem  Adding: animal wastes from livestock farming, and untreated human sewage. This can lead to fish death  Reducing: Slash and burn practices Releases phosphate from trees in the form of ash, and Phosphates accumulate in the soil and is leached from the ash into the water ways, where is settles and becomes unavailable to orgainisms.

How do changes in your nutrient cycle affect Biodiversity  Any significant changes to any of these nutrients (C, N, P, O and H) can greatly impact the health and biodiversity in an ecosystem. Phosphorous can affect food chains. Decreased phosphorous has reduced algae production in some lakes, which is an important source for herbivores.

Where can we find Phosphorus in our Biosphere?  We can find Phosphorous in plants. It is important for root growth, stem growth and seed production. It is also found in animals including humans. In animals it is important for bone strength. It enters our environment through the weathering of sedimentary rock. It is in water, soil and sediments.

How is Phosphorus stored?  Phosphorous is trapped in phosphate that makes up phosphate rock and sediments of ocean floors unlike carbon, oxygen and nitrogen. It is not stored in the atmosphere as a gas.

Describe how Phosphorus is cycled through the ecosystem  Through weathering and geological uplift  There are two types of weathering: physical and chemical

Physical Weathering  Phosphorus is cycled through the ecosystem by weathering when rocks and minerals containing phosphate are broken down into smaller fragments. The phosphate is generally released from rocks or minerals into water where it can be deposited on the ocean floor, river bank, etc.

Chemical Weathering  A chemical reaction that releases phosphate into soil. Ex. Acid Precipitation or lichen

Geological Uplift  Phosphate originates as salts in ocean sediments or in rocks  Geological uplift brings these sediments to the surface  Weathering releases the phosphate ions  Plants can absorb these phosphates from the soil, and use them in cellular processes  Phosphate may be passed on to animals when they are consumed by herbivores, and in turn consumed by carnivores  After death, organism decays and the phosphates are returned to soil by bacterial decomposition  The runoff from the land may run off into the ocean, and its reincorporated into the rocks

How is Phosphorus returned to the atmosphere?  It not returned to the atmosphere. It is excreted through the waste products created by animals, and is released by decomposing plants and animals.  Earth’s Crust  Ocean Sediments  Mineable Phosphates  Terrestrial Organisms  Marine Life  Only when the rock layers are exposed through a process called geologic uplift will phosphorus be made available, and then the cycle of weathering can begin again. Phosphate is mostly stored in ocean sediments, earths crust and minable phosphate.