Nitrogen cycle氮循环.pptVIP

Nitrogen cycle氮循環 Nitrogen fixation 固氮作用 symbiotic nitrogen fixing bacteria (Rhizobium) in root nodules of leguminous plants 豆科植物根瘤內的共生固氮細菌 atmospheric nitrogen ------- ammonium ions supplied to the plant for protein synthesis 將大氣中的氮轉化成銨離子供植物用作合成蛋白質 bacteria obtain shelter and carbohydrates from the plant 細菌由植物獲得保護及碳水化合物 * Nitrate in soil 泥土中的硝酸鹽 Plants植物 Animals動物 Ammonia and ammonium compound氨及銨化合物 Nitrite in soil泥土中的亞硝酸鹽 Nitrogen in the atmosphere 大氣中的氮 Absorption 吸收 Ingestion攝食 Dead remains, egesta,excreta 屍體, 糞便, 排泄物 Death 死亡 Death, egestion, excretion死亡,排遺, 排泄 Ammonification or putrefaction by putrefying bacteria and fungi 腐敗細菌及真菌的氨化作用或腐敗作用 Nitrification by nitrite bacteria亞硝酸細菌的硝化作用 Nitrification by nitrate bacteria硝酸細菌的硝化作用 * Nitrogen fixation by symbiotic nitrogen fixing bacteria 共生固氮細菌的固氮作用* Free living nitrogen fixing bacteria 自由生活的固氮細菌 Nitrogen fixation固氮作用 Death死亡 Lightning閃電 Denitrification by denitrifying bacteria反硝化細菌的反硝化作用 * Industrial synthesis 工業合成 (fertilizers 肥料) Absorption吸收 Leaching淋溶 硝化作用 Nitrification Conversion of ammonia to nitrite by nitrite bacteria 亞硝酸細菌將氨轉化成亞硝酸鹽 2NH3 + 3O2 2HNO2 + H2O + ENERGY Conversion of nitrite to nitrate by nitrate bacteria 硝酸細菌將亞硝酸鹽轉化成硝酸鹽 2HNO2 + O2 2HNO3 + ENERGY Nitrifying bacteria (nitrite and nitrate bacteria) 硝化細菌 (亞硝酸細菌及硝酸細菌) are chemosynthetic bacteria i.e. they can synthesize organic compound from inorganic materials with energy obtained from the oxidation of inorganic materials 為化合細菌, 它們利用來自氮化無機物的能量將無機物質轉化成有機化合物 are active in alkaline and well aerated soil 在鹼性及有充足氧氣的泥土較活躍 Denitrification 反硝化作用 Conversion of nitrate to gaseous nitrogen by denitrifying bacteria 反硝化細菌將硝酸鹽轉化成氮氣 decreases the availability of nitrogen to living organisms 減少可供給生物的氮 are active in warm and poorly aerated soil (e.g. waterlogged soil)