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Environment Book Summary Presented B Aartee Mishra
CHAPTER 2 FUNCTIONS OF AN ECOSYSTEM (Part-3)
NITROGEN CYCLE A BIOGEOCHEMICAL CYCLE Nitrogen plays a vital role in the survival of all living organisms. It is one of the primary nutrients and component of biomolecules such as chlorophyll, DNA, and proteins. Nitrogen is the most abundant element present in the atmosphere. Even though it is widely available, it acts as a scarce resource. Only when used in ammonia, it can be used by primary producers such as plants. . NH, NITROGEN FIXING BACTERIA DENITRIFICATION BACTERIA NO NH NO NITRIFICATION NITRIFYING BACTERIA
Nitrogen in atmosphere Anthropogenic emission (NOT 1. Deposition 1 8 IFertilizers, crop and livestock 7. production Nitrogen organic matter in soil I 2. 2. 5. 4. Nitrite 4 Ammonium Nitrate (NO,) sol and water(NO21 soil and water (NH4) sall and water
Here are the different types of processes combined with the nitrogen cycle Nitrogen fixation Atmospheric nitrogen is converted into the usable form by lightning strikes or symbiotic bacteria which are known as Diazotrophs. These bacteria consist of a nitrogenase enzyme which has the capability to combine gaseous nitrogen with hydrogen to form ammonia. Ammonification When plants or animal die organic nitrogen is again released back into the soil. Bacteria or fungi present in the soil convert them back into ammonium. This process is also called as mineralization. . Assimilation Primary producers take in this gas from the soil with the help of their roots in the form of amino acids, nitrite ions, nitrate ions or ammonium ions. This way it enters the food cycle when the consumers eat the plants
N2 Dentrification Nitrogen fixation Ammonification Nitrogen fixing Bacterla NH4 Assimilation Denltrification bacterla NO2 NH3 NO3 Nitrifying bacteria
Nitrification .In this process, the ammonia is converted into nitrate by the presence of bacteria in the soil. Nitrites are formed by the oxidation of Ammonia with the help of Nitrosomonas bacterium species. Later, the produced nitrites are converted into nitrates by Nitrobacter. This conversion is very important as ammonia gas is toxic for plants. Denitrification In order to complete the nitrogen cycle, the nitrites are reduced back to inert nitrogen gas in this process. This is done by bacterial species such as Clostridium and Pseudomonas in the absence of oxygen.