Which of the following statements are correct about nutrient cycle ?
A. Carbon dioxide gas which makes up about 0.040% of the volume of the earth's atmosphere
B. Specialised bacteria convert most of the $NH_3$ and $NH_4^+$ in the soil to nitrate ions $NO_3$-
C. Phosphorus does cycle through the atmosphere and its cycle is fast
D. Much of the earth's sulfur is stored underground in rocks and minerals
Choose the most appropriate answer from the options given below:
Nutrient Cycle Statements: A, B, D Correct Explained
This section explains the correctness of statements related to nutrient cycles, focusing on atmospheric composition, nitrogen conversion, phosphorus movement, and sulfur storage.
Statement A: Carbon Dioxide Concentration
The statement that carbon dioxide ($CO_2$) gas makes up about 0.040% of the Earth's atmosphere is correct. Current atmospheric concentrations hover around 420 parts per million (ppm), which is equivalent to approximately 0.042%. Therefore, 0.040% is an accurate representation.
Statement B: Soil Bacteria and Nitrogen Conversion
This statement describes the process of nitrification, which is a crucial part of the nitrogen cycle. Specialized bacteria in the soil play a vital role in converting ammonia ($NH_3$) and ammonium ($NH_4^+$) ions into nitrate ions ($NO_3^-$). This process involves multiple steps, starting with the oxidation of ammonia/ammonium to nitrite ($NO_2^-$) by bacteria like Nitrosomonas, followed by the oxidation of nitrite to nitrate by bacteria like Nitrobacter. Thus, the statement is correct.
Statement C: Phosphorus Cycle Dynamics
The statement claims that phosphorus cycles through the atmosphere and its cycle is fast. This is incorrect. The phosphorus cycle is primarily a terrestrial and aquatic cycle. Unlike carbon and nitrogen, phosphorus does not have a significant gaseous phase that cycles through the atmosphere. Its main reservoir is in rocks and sediments. The weathering of rocks releases phosphorus into the soil and water, making its cycle relatively slow compared to cycles involving atmospheric components.
Statement D: Sulfur Storage
The statement indicates that much of the Earth's sulfur is stored underground in rocks and minerals. This is correct. Large quantities of sulfur are found in the Earth's crust, mainly in sedimentary rocks as sulfide minerals (like pyrite, $FeS_2$) and sulfate minerals (like gypsum, $CaSO_4 \cdot 2H_2O$). Fossil fuels, such as coal and oil, also contain significant amounts of sulfur.
Conclusion on Correct Statements
Based on the analysis, statements A, B, and D are correct descriptions of aspects related to nutrient cycles. Statement C is incorrect because the phosphorus cycle does not significantly involve the atmosphere and is generally a slower process.
Therefore, the correct option includes statements A, B, and D.
Important Questions from Ecology and Ecosystem
Which one of the following is an example of ex situ conservation of biological resources?
All eco-systems begin with energy input from-
What is the transition zone between two ecosystems known as?
Given below are two statements one is labelled as Assertion (A) and the other is labelled as Reason (R):
Assertion (A): It is crucial to sustain Himalayan ecosystem
Reason (R): Himalayan ecosystem is home to a number of indigenous tribes.
In the light of the above two statements choose the correct answer from the options given below
Among all recorded species in the world, India accounts for about
