Different environments can be affected by various types of pollution. how would bacteria and algae in a pond kill fish and other aquatic wildlife?

By using the majority of oxygen present in the water.

Explanation:

Bacteria and algae present in a pond would probably kill fish and other wild aquatic species as they can utilize the majority of the oxygen present in the water body. Fish and other species found in such waters surely would require more oxygen in order to thrive.  

Thus, if algae and bacteria would consume the majority of the oxygen found in water, then naturally the species present in the water would be not able to survive the loss of that very essential constituent.  

step 1: nitrogen fixation- conversion of atmospheric no₂ into forms useful to plants by lightning, bacteria, and cyanobacteria.

step 2: nitrification-process of converting ammonia to nitrite or nitrate.

step 3: assimilation-plant roots absorb new form of nitrogen.

step 4: ammonification-conversion of organic nitrogen to ammonia by bacteria involved in decomposition.

step 5: denitrification-bacteria turns the decomposed matter back into n₂o, which is released into atmosphere; repeat cycle.