Answer:
The correct answer is algae bloom
Step-by-step explanation:
Algae bloom is a situation in which there is an uncontrollable increase in the amount/growth of algae in a water body (freshwater or marine water). This abnormal increase eventually gives the water body a different colour which is from the pigment of the algae. The processes involved in algae bloom leads to lowered oxygen levels in the water-body which causes the death of several aquatic organisms in the water-body. Since water pollution can be described as the processes involved in causing adverse effects that can contaminate a water-body which can lead to loss of aquatic animals and/or affect the physical properties of the water, algae bloom (as described earlier) is the correct option.
NOTE: volcanic activities and earthquakes may cause air pollution as they release several substances into the air but can hardly be directly linked to water pollution.