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UPSC Prelims & Mains Questions
In case of which one of the following biogeochemical cycles, the weathering of rocks is the main source of release of nutrient to enter the cycle?
A)
Carbon cycle
B)
Nitrogen cycle
C)
Phosphorus cycle
D)
Sulphur cycle

Correct Answer :   Phosphorus cycle

Note :

The phosphorus cycle is the biogeochemical cycle that describes the movement of phosphorus through the lithosphere, hydrosphere, and biosphere. Unlike many other biogeochemical cycles, the atmosphere does not play a significant role in the movement of phosphorus, because phosphorus and phosphorus-based compounds are usually solids at the typical ranges of temperature and pressure found on Earth. The production of phosphine gas occurs in only specialized, local conditions. Therefore, the phosphorus cycle should be viewed from whole Earth system and then specifically focused on the cycle in terrestrial and aquatic systems.
 
The global phosphorus cycle includes four major processes :

(i) tectonic uplift and exposure of phosphorus-bearing rocks such as apatite to surface weathering;

(ii) physical erosion, and chemical and biological weathering of phosphorus-bearing rocks to provide dissolved and particulate phosphorus to soils, lakes and rivers;

(iii) riverine and subsurface transportation of phosphorus to various lakes and run-off to the ocean;

(iv) sedimentation of particulate phosphorus (e.g., phosphorus associated with organic matter and oxide/carbonate minerals) and eventually burial in marine sediments (this process can also occur in lakes and rivers)

Year : 2021
Category : General Studies
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