Question

The phosphorus cycle is important to ecosystems. Choose all of these statements that are true concerning the phosphorus cycle.

Answer 1

Answer:

The largest reservoir of phosphorous is sedimentary rock.

Major sources of phosphorous to aquatic ecosystems are fertilizer runoff, sewage leaks, and industrial wastes.

Eccess phosphorous can lead to eutrophication

Explanation:

Phosphorus come from different sources such as aquatic ecosystems and fertilizers used for plants. When these substances containing phosphorus and those from industrial wastes find their way into water bodies, they tend to cause eutrophication, which is the natural enrichment of water bodies.  

Also, it is known that a very small portion of phosphoric acid contribute to acid rain in the atmosphere.  

Answer 2

Answer:

The statements that are true are:

-The largest reservoir of phosphorous is sedimentary rock

- Major sources of phosphorous to aquatic ecosystems are fertilizer runoff, sewage leaks, and industrial wastes.

- Excess phosphorous can lead to eutrophication.

Explanation:

In nature, phosphorous is found in form of phosphate ions PO₄⁻³, which are forming part of sedimentary rocks. Upon the action of wind and rain, phosphorous is washed into the soil (it dissolves and its passes into the soil in form of phosphate compounds). So, the largest reservoir of phosphorous is sedimentary rock.

Phosporous in the soil is absorbed by animal and plants and it is transformed in biological components (like nucleic acids, phospholipids, etc), and when animal and plants die, phosphorous return to the soil. So, the most of the phosphorous cycle occurs in the Earth (soil, water, living beings). In fact, phosphorous does not circulate through atmosphere.

Human activities such as farming and industry impact in phosphorous cycle. Fertilizers, wastes from human activities and phosphorous-containing products are poured in oceans and they feed the cycle.

But the excess of phosphorous often leads to an overgrowth of algae, which causes a lack of oxygen in water and consequenty the death of aquatic organisms. This fenomena is called eutrophication.

Finally, the major acid found in acid rain is sulphuric acid (it is not phosphoric acid).