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NUTRIENTS CYCLEPREPARED BY:ABUSO, CHRISTELLE B.BS ARCHI 4-1

NUTRIENT CYCLE These are chemical elements that all plants and animals require forgrowth. - There is aconstantandnatural cyclehow these elements are incorporated when an organism grows, and degraded if an organism dies.NUTRIENTS

The most important are those involving the elements:

Carbon dioxideOxygenNitrogenPhosphorus

- A concept that describes how nutrients move from the physical environment into living organisms and subsequently are recycled back to the physical environment.

This movement of nutrients is essential to any given ecosystem, and it must be balanced and stable for the system to be maintained so that the organisms that live in that environment are to flourish and be maintained in a constant populationNUTRIENT CYCLE

OXYGEN CYCLE

Photosynthesis, which releases oxygen into the air.2. This, in turn, is absorbed by oxygen-breathing organisms, which combine it with carbon and release carbon dioxide into the atmosphere.3. Carbon dioxide from other sources, such as the decomposition of dead organic material and the burning of fossil fuels, is also used in photosynthesis, producing oxygen.

CARBON CYCLEPhotosynthesis- process by which plants use energy fromsunlightto combine carbon dioxide that they use to build cells or storeasfood.2. Herbivores eat the plants that transfer some carbon that they can use to build and repair their cells and provides energy to them.3.Through respiration, it is combined with oxygen from the air to form CO2, which is then exhaled, returning the carbon directly to the atmosphere. 4. The carbon stored in the body of a herbivore can be recycled when the animal dies.

CARBON CYCLE5. Dead plant and animal matter is decomposed by other organisms, such asfungiand bacteria. This process releases carbon, in the form of carbon dioxide, back into the atmosphere.6. Deadorganic mattercan be buried under sediment. This buried material has formed deposits ofcoaland oil, which humans are now exploiting asfossilfuels. The combustion of these compounds forms carbon dioxide, which is released into the atmosphere. 7. Some types of marine organismscan combine dissolved carbon dioxide withcalciumto build shells. When it dies, the shells accumulate as sediment, Over vast timescales, this can be uplifted to the surface by geological processes, where acidic water can react with it to release CO2back into the atmosphere.

NITROGEN CYCLENitrogen is an essential element for all known life forms, and it is required to form amino acids, proteins, andDNA. This element cannot be used directly.1. The energy come from lightning causes some nitrogen to combine with oxygen, forming nitrogen oxides. These can dissolve in rainwater to form very dilute nitric acid, which reacts with minerals in soil to form nitrates that are easily absorb by plants.

2 MAIN WAYS TO MAKE NITROGEN AVAILABLE TO LIVING ORGANISMS

NITROGEN CYCLENitrogen is an essential element for all known life forms, and it is required to form amino acids, proteins, andDNA. This element cannot be used directly.2.NITROGEN FIXATION - This involves the conversion of atmospheric nitrogen in soils into ammonia by various types of bacteria. One such group of bacteria calledRhizobium, forms nodules in the roots of peas and beans. For this reason, these plants are often grown as crops by farmers when the soil needs to be enriched with this element. MAIN WAYS TO MAKE NITROGEN AVAILABLE TO LIVING ORGANISMS

NITROGEN CYCLENitrogen is an essential element for all known life forms, and it is required to form amino acids, proteins, andDNA. This element cannot be used directly.3. DENITRIFICATION - returns nitrogen gas to the atmosphere. This is performed by bacteria, which reduce nitrates in the soil to nitrogen.

PHOSPHORUS CYCLE

1. The main natural source of phosphorus is from rocks. The element enters water and soil in the form of phosphates through erosion and weathering, and it is taken up by plants. 2. It then progresses through the food chain via herbivores and carnivores, returning to the soil when these organisms die.3. Phosphates can be washed out of the soil by rainwater, accumulating in lakes and rivers, where some of it is used by aquatic plants and other organisms.

PHOSPHORUS CYCLE

4. Some of the phosphate, however, undergoes chemical reactions that form insoluble compounds that are deposited as sediments. These eventually form rock and, in this way, phosphorus can be locked up for very long periods5. Geological processes may uplift this rock, allowing erosion and weathering to return it to living organisms.

HUMANS INFLUENCE NUTRIENT CYCLE

Agriculture accelerates land erosion because plowing and tilling disturb and expose the soil so morenutrientsdrains away withrunoffFlooding causes too muchnutrientsfrom eroded soil that confine in water bodies resulting to spurs massive, uncontrolled blooms of algae that when it dies theirdecay starves other organisms of oxygen, creating DEAD ZONES and contributing to the depletion of fisheries

The problem with the human alterations, such as using artificial fertilizer, to naturalnutrient cycle is the one that we are extractingnutrientsfrom the soil, and discharging them essentially in aquatic environment thisleadsto a heavy imbalance with severe consequences.