Opposite is true, many of common biological elements and compounds such as carbon, nitrogen and phosphorus are recycled
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What common features do all nutrient cycles have?
Nutrients taken up by producers. Nutrients are incorporated into organic molecules. Consumers eat the producers or the other consumers which passes on the nutrient.
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what next
When producers and consumers die saprobiontic microorganisms release the nutrient in its simple form
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What are saprobiontic bacteria?
Fungi and bacteria that secrete enzymes digest organic material then absorbed and returned to soil
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Why is phosphorus important?
Found in ATP, Phospholipids, DNA- needs constant recycling
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What does phosphate normally exist as?
Phosphate ion (PO4^3-) in rock deposits
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What enables these ions to dissolve and become available for absorption by plants?
Weathering and erosion of rocks
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What do consumers then do?
Eat plants and the nutrients will be passed on
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What can excess phosphate ions then do?
Excreted on death of producers or consumers- bacteria and fungi break them down releasing the phosphate into the water or soil
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Step 1
Rainerodes rocks releasing phosphate into soil (mineralised) p dissolved in water into water course or soil
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2
Plants take up P by diffusion and AT by roots from soil
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3
Plants encorporate into phospholipids and nucleotides - becomes part of it ADP and ATP
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4
Into animals (consumers eat and digest encorporate into tissues
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5
Animals/ plants die
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6
Decomposed by saprobionts put P into soil
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Other way
Trapped in sediment pushed down uplifted by geological uplift or rain
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Role of mycorrhizae?
Associations b/w types of fungi and roots in most plants. Fungi act like extensions of the plants root system hence inc SA for absorption of water and minerals
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What do they do
Improve uptake of scarce ions such as phosphate- mycorrihzal relationship b/w fungi and plants is mutualistic both organisms benefit from the arrangement
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Problem with N
Atmosphere is 78% N but few organisms can use atmospheric nitrogen directly
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What do plants do
Take up the majority of their nitrogen in the form of nitrate ions (NO3-). These ions are absorbed by AT
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How do animals obtain their N
By eating and digesting plant material
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What are N ion? what does this mean?
V soluble, can leach (wash away) from the soil away from plants
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What does the N cycle restore
Nitrate levels to enable plants to uptake nitrate
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In agriculture, what can be added to the soil to further inc nitrate levels to inc yield
Fertilisers
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What does the N cycle have and what is vital at each stage?
4 main stages, role of sabrobiontic microorganisms
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First stage?
Nitrogen fixation- N2 reduced to ammonia- atmospheric N gas into nitrgoen containing compounds occurs when lightening strikes but more importantly it is carried out by 2 types of microorganism
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First type
Free living N fixing bacteria which reduce gaseous N to ammonia which can then be used to make AA's
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2ND type
Mutualistic N fixing bacteria that live in root nodules of leguminous plants eg beans peas clovers. Bacteria get Carbohydrates and plants get amino acids
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Second stage
Ammonification- Production of ammonia from organic compounds- when organisms die or release waste the urea, protein nucleic acids and vitamins are digested by saprobiontic microbes that release ammonia which forms ammonium ions in the soil
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3RD
Nitrification- Ammonium ions are converted into nitrates in an oxidation rxn. This is a 2 staged process
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stage
First ammonium ions are converted to nitriles (NO2-) and then nitriles are oxidised to nitrates (NO3-) carried out by nitrifying bacteria. that req o2 pence soil must be aerated via ploughing to ensure conditions are kept aerobic
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Denitrification?
When soil becomes waterlogged and low in o2 there is a dec aerobic nitrifying bacteria and an inc in anaerobic denitrifying bacteria that convert soil nitrates into gasous nitrgoen
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Other cards in this set
Card 2
Front
What about in the case of nutrients?
Back
Opposite is true, many of common biological elements and compounds such as carbon, nitrogen and phosphorus are recycled
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