Questions
1. Compare and contrast gaseous biogeochemical cycle and sedimentary biogeochemical cycle.
2. Calcium and phosphorous cycles are sedimentary cycles. Justify.
3. Identify and explain two physical processes responsible for eroding phosphorous from the land.
4. Explain how humans influence or disrupt the biogeochemical cycles.
5. Strategize ways to maintain balance in thebiogeochemical cycles in the ecosystem.
6. What is biogeochemical cycle?
Answers
1. Gaseous cycles include those of nitrogen, oxygen, carbon, and water; sedimentary cycles include those of iron, calcium, phosphorus, and other more earthbound elements. In a sedimentary cycle elements move from land to water to sediment. Main reservoirs are the soil and sedimentary rocks.
2. The phosphorus cycle is a sedimentary cycle (unlike carbon, oxygen, and nitrogen), the atmosphere is not a reservoir for phosphorous nor do microorganisms fix phosphorus as they do nitrogen. Phosphorus enters the biosphere almost entirely from the soil through absorption by plant roots.
3. The global phosphorus cycle has four major components:
(i) tectonic uplift and exposure of phosphorus-bearing rocks to the forces of weathering;
(ii) physical erosion and chemical weathering of rocks producing soils and providing dissolved and particulate phosphorus to rivers;
(iii) riverine transport of phosphorus to ...
4. Human activities have greatly increased carbon dioxide levels in the atmosphere and nitrogen levels in the biosphere. Altered biogeochemical cycles combined with climate change increase the vulnerability of biodiversity, food security, human health, and water quality to a changing climate.
5. (i) Avoid using phosphorus fertilizers and nitrogen fertilizers.
(ii) Avoid deforestation, and clearing of vegetation to increase the carbon sinks and decrease the atmospheric CO2 concentration.
(iii) Prevention of acid rains, burning of coal and livestock ranching.
(iv) Reduce vehicular pollution.
(v) Overall reduction in pollution.
