 The Haber process has enabled ammonia to be produced on an industrial scale. Ammonia, as we know, can be used to make fertilizers. The large-scale production of ammonia-based fertilizers such as ammonium nitrate and ammonium sulfate has made it possible to sustain global food production. Although it may seem as if this is a good thing, there are actually very serious environmental and social consequences from the overuse of these fertilizers. Fertilizers must be dissolved in water before they can be absorbed by plants through their roots. This can happen for manual watering or rainfall. Heavy rainfall, however, can wash dissolved fertilizers into large bodies of water such as rivers and lakes. In fact, even without heavy rain, dissolved fertilizers can still leach from soil into water. We have to remember that there are also aquatic plants or plants that grow exclusively in water. The presence of these fertilizers will cause them to grow faster than usual. This is called eutrophication. The main issue here is that most of these aquatic plants are not a food source for humans. These plants just grow and die and they decay. Dead and decaying plant matter blocks sunlight from reaching live aquatic plants and thus prevents photosynthesis from occurring. So these plants also die and decay. In fact, it doesn't end here. Aerobic bacteria which require oxygen to live feed on these decaying plant matter. These bacteria then also grow faster than usual and consume a lot of oxygen. This then decreases the concentration of dissolved oxygen in water. So fish and other aquatic organisms suffocate and die. Now that we've looked at the environmental consequences, can you think about a few social consequences? Please pause the lesson to think about this and resume when you are ready. Fish are a main food source for some communities. So fewer fish means less food for people who live in these communities. As well, some communities rely heavily on the fishing industry. So fewer fish caught could mean that many people will struggle to make a living. Dissolved fertilizers can also cause algae or microscopic aquatic plant organisms to grow quicker than usual. When they grow too quickly, a phenomenon known as an algal bloom occurs. An algal bloom could span over many kilometers in a large body of water, thus blocking sunlight from reaching other aquatic organisms. The same scenario occurs. Aerobic bacteria feed on all the dead and decaying algal matter and are then able to thrive and multiply. They consume oxygen and decrease the concentration of dissolved oxygen in water, suffocating aquatic organisms.