Nitrogen Cycle nitrogen 3.0 / 5 based on 2 ratings ? BiologyEnergy flow through ecosystemsGCSEAll boards Created by: Emily MooreCreated on: 07-05-10 16:57 Nitrification and Denitrification Nitrification Ammonium compounds ----> Nitrites ----> Nitrates NITRIFYING BACTERIA carry this out Denitrification Nitrates ----> Nitrogen gas DENITRIFYING BACTERIA carry this out ANAEROBIC respiration e.g. in waterlogged soils - no oxygen 1 of 4 Nitrogen fixing Nitrogen fixing Nitrogen ----> Nitrates NITROGEN FIXING bacteria carry this out. Found in the root nodules of leguminous plants e.g. peas/ beans Symbiotic relationship with plants: - bacteria provide plants with nitrogen compounds - plant provides them with nutrients 2 of 4 Biological Control Definition: An organism is used to kill off another Example: Aphids pierce PHLOEM - **** plant sap high pressure --> aphids 'bloat up' + exude sap fungal spores grow in sap --> covers leaf less sunlight reaches + stomata blocked so less C0 absorption less photosynthesis --> less growth Methods of control: 1. ladybirds 2. encarsia (wasp) - larvae inside, hatch and eat from inside 3 of 4 Greenhouse Gases Greenhouse gases: absorb INFRARED radiation e.g. CO and CH Sun's rays enter atmosphere ---> heat up Earth Earth produces INFRARED radiation to cool itself down Some escapes but most ABSORBED and REFLECTED back to Earth by greenhouse gases This warms the Earth up and so the cycle continues... Ozone: nitrogen oxides react with hydrocarbons in reaction CATALYZED by SUNLIGHT Smog: mixture of pollutants and particulates 4 of 4
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