I am currently taking chemistry as part of my prerequisite courses for grad school. A lot of chemistry doesn’t seem that relevant, but one of my assignments is to write a paper and it can be on anything related to chemistry. This allowed me to look at the more broad view of chemistry (rather than tiny molecules and atoms) and I have discovered interesting things. I won’t bore you with the whole paper, but I looked into algae blooms when they are caused by eutrophication which is excessive amounts of nutrients in a body of water.
Eutrophication often occurs when nitrates and phosphates are suddenly found in excess. Algae are able to use this excess nitrogen and phosphorus to grow exponentially. It appears that algae can use phosphates from a variety of sources to gain this critical component to their cellular activity. The biggest industry in phosphates is agricultural fertilizers but they also appear in laundry detergents and human and animal waste. Agricultural runoff brings the phosphorus in fertilizers from cropland to lakes, rivers and the ocean. This runoff also includes phosphates that come from animal waste. Phosphates in human waste and household cleaning products like laundry detergents end up in wastewater, much of which also eventually ends up in lakes, rivers and the ocean. Problems occur because some of the algae is toxic and can contaminate drinking water and the fisheries and potentially poison human food. The other big affect is the decrease in oxygen in the water. The algae are stimulated to grow through excess nutrients, but this growth means they are taking other nutrients, such as oxygen, out of their environment. This can cause the death of other aquatic organisms who require enough oxygen to survive.