Nutrient Cycles In The Natural Ecosystem

They act as a type of decomposers. They feed on dead animalsand plants and on their waste products, breaking them down. It allows importantchemical elements in the remains and waste to be recycled.

Saprobionts secrete enzymes and feed usingextracellular digestion.

When food is digested outside a cell. During this organic molecules are brokendown into inorganic ions

Obtainingnutrients from dead organic matter and animal waste using extracellulardigestion

The symbiotic relationships betweena fungus and roots of plants

The fungi are made up of hyphae, which are long thin strands that connect to the plants roots. The hyphae increase the surface area of the plants roots system helping the plants to absorb ions from the soil that are usually scarce (e.g. phosphorus). Hyphae also increase the uptake of water by the plant. In return the fungi obtain organic compounds such as glucose from the plants

when nitrogen gas from the atmosphere is turned into nitrogen containingcompounds by nitrogen fixing bacteria.Nitrogen fixing bacteria such as Rhizobium is used to turn nitrogen into ammonia. The ammonia can be used byplants. Some nitrogen fixing bacteria are found in roots of a plant andsome in the soil. Rhizobium are foundinside root nodules of leguminous plants. They form a mutualistic relationshipwith the plants. A mutualistic relationship is a type of symbiotic relationship where both species benefits.The bacteria provides the plant with nitrogen compounds and the plant providesthe bacteria with carbohydrates.grU_;M

Ammonification is when nitrogen compounds from deadorganism are turned into ammonia and ammonium ions by saprobionts.Animal waste also contains nitrogen compounds. These are also turned intoammonia and ammonium ions by saprobionts

When ammonia and ammonium ions in the soil are turnedinto nitrogen compounds by nitrifying bacteria that can be used byplants. Nitrifying bacteria change ammonia and ammonium ions intonitrites. Then another nitrifying bacteria turns nitrites into nitrates

Denitrification is when nitrates in the soil areconverted into nitrogen gas by denitrifyingbacteria- they use nitrates in the soil to carry out respiration andproduce nitrogen gas. This happensunder anaerobic conditions

Thebreakdown of rocks by mechanical, chemical and biological processes. Phosphate ions in rocks are released into thesoil by weathering. Phosphate ions are taken intothe plants through the soil. Weatheringof rocks also releases phosphate ions into seas, rivers and lakes. This istaken up by aquatic producers and passed along the food chain.

It greatly increase the rate at whichphosphorus can be assimilated.Phosphate can be transferred through the food chain as animals eat the plantsand are in turn eaten by other animals. When plant and animals die saprobionts breakdown theorganic compounds releasing phosphate ions into the soil. They also release phosphate ions fromplants and animals waste.listic g_;,BM�

To makeproteins and nucleic acid

To convert nitrogen gas into nitrogen containing compound because plants and animals cannot use nitrogen directly from the air

makebiological molecules such as phospholipids, DNA and ATP

Rocks and dissolved in the oceans in the formof phosphate ions