ECOLOGY
CHEMICAL CYCLES
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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A decrease in the amount of lightning strikes.
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An increase in fertilizer usage at local farms.
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An increase in the biomass forming plants.
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A decrease in bacterial colonies within the soil.
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Detailed explanation-1: -Scientists have detected a dramatic decrease in usable nitrogen levels in the soil of a local ecosystem. Which of the following is a likely theory to explain this problem? A decrease in the amount of lightning strikes.
Detailed explanation-2: -If all the nitrogen-fixing bacteria disappeared, plants and animals wouldn’t receive the nitrogen compounds they need to carry out certain functions. The absence of this important source of nitrogen would probably cause disease and death among plants, which would lead to declines in animal populations.
Detailed explanation-3: -Some organic nitrogen falls to the ocean floor as sediment. Other organic nitrogen in the ocean is converted to nitrite and nitrate ions, which is then converted to nitrogen gas in a process analogous to the one that occurs on land.
Detailed explanation-4: -Organisms are unable to grow in the absence of nitrogen fixation. Plants that are deficient in nitrogen appear pale or yellowish. They produce quite fewer flowers & fruits than other plants. The majority of plants will also not be able to directly consume nitrogen from the environment.
Detailed explanation-5: -The symbiotic nitrogen-fixing bacteria invade the root hairs of host plants, where they multiply and stimulate formation of root nodules, enlargements of plant cells and bacteria in intimate association. Within the nodules the bacteria convert free nitrogen to ammonia, which the host plant utilizes for its development.