2. Ecosystems
Nutrient pollution from upstream (creeks and streams) often flow downhill and even travel miles into other larger water bodies. The effect is that, it breeds algae growth and causes the growth of many more water organism. This algae attack affects fish and other aquatic animals by absorbing and reducing their oxygen supply. Algae growth also clogs fish gills. Naturally, the order of ecosystems in that water are affected negatively, as the destruction or introduction of any foreign organism alter the entire food chain in there.