Answer to Question #150087 in Biology for pro gamer

Question

when mineral ions from soils are washed into streams and rivers there is often a rapid growth of algae these streams and rivers often have low concentrations of dissolved oxygen explain why

Answer 1

Normally algae numbers in the river water are low due to the low availability of nutrients. But ff the fertiliser is leached into the river, algae use them as food and therefore they can multiply very rapidly. The breakdown of dead algae by decomposing microorganisms can greatly reduce the concentration of oxygen dissolved in the water.