Which statement best describes a human influence on the biogeochemical cycles?
a. increased eutrophication caused by high levels of nitrogen and phosphorous
b. increased nitrates available due to inaccurate methods of denitrification
c. increased global warming due to alternative energy sources
d. increased amount of water that is available to freshwater ecosystems
Answers
Answer:
A) Increased eutrophication caused by high levels of nitrogen and phosphorus.
Explanation:
The balanced recycling of ‘inorganic matter’ between organisms and their environment to sustain equilibrium is known as biogeochemical cycle. Nitrogen and phosphorous cycles are two such cycles. Atmospheric nitrogen is converted to biologically usable form in nitrogen cycle. Phosphorous from rocks and soils that get washed away by rain and again distributed to them is the phosphorous cycle. ‘Human activities’ have increased nitrogen content in the atmospheric.
Overgrazing and deforestation have leads to increased phosphorous contents. These when fixed into water bodies, greatly accelerates the growth of phytoplanktons, a process known as eutrophication which causes algal bloom. They deplete water oxygen levels and cause death of ‘aquatic life’ and results in poor water quality.