The passage describes the ecological impacts of organic pollution and eutrophication in a freshwater stream. Complete the passage by writing a suitable word or words in each of the spaces.
The discharge of concentrated organic slurry from an intensive dairy farm into a freshwater stream triggers a cascade of ecological changes. Rainwater washes these pollutants from the fields into the stream channel by the process of [1] \text{\_________________}. The slurry is rich in inorganic mineral ions, notably [2] \text{\_________________}, which stimulate the rapid growth of [3] \text{\_________________} near the surface of the water, forming a dense mat that blocks light.
Additionally, the slurry contains high amounts of organic nitrogenous waste, such as [4] \text{\_________________}. Saprobiotic [5] \text{\_________________} feed on this organic matter, multiplying rapidly. As these decomposers carry out aerobic [6] \text{\_________________}, they severely deplete the concentration of dissolved [7] \text{\_________________} in the water column, causing death of fish and other aerobic aquatic organisms.
