Watersheds may be contaminated by fertilizers and other pollutants. When these substances enter a waterway, they can cause algal blooms, which are rapid overgrowths of algae. When the algae die, the decay uses up a large portion of dissolved oxygen. Declining oxygen levels can then cause large die-offs of animals in the waterway. What will an algal bloom in a watershed most likely cause?

Completed options

A)A decrease in the watershed’s biodiversity, which will reduce its ability to supply clean and safe drinking water.

B)A decrease in the watersheds ecosystem diversity, which would improve its ability to supply large volumes of water.

C)An increase in the watersheds genetic diversity, which would reduce its ability to supply clean and safe drinking water.

D)An increase in the watersheds species diversity, which would improve its ability to supply large volumes of wate

)A decrease in the watershed’s biodiversity, which will reduce its ability to supply clean and safe drinking water.

Explanation:

This sequnces of events is called  Eutrophication. It is the process of washing of  nutrients salts e.g., (NPK) into aquatic bodies which leads to change in the  ecosystem structure of the  aquatic bodies with the boom in algae growth, and drop in O2.

The cut in oxygen availability  in the aquatic bodies , leads to death of the fauna and flora.Theses are the varieties of life in this habitat.(biodiversity).

With the an increase in the death of these inhabitants(flora and fauna)couple with the activities of the (decomposers) the water bodies becomes dirty and unfit for drinking.

Besides as the pathways of the  watershield  ecosystem  as it filters the these polluted  water may be blocked by the dead organic matter from the flora and fauna. Thus A is the best.  

c.more precipitation,but only when emission levels.