How Do Dead Zones Affect Humans

When the algae eventually dies, the oxygen in the water is consumed. … Elevated nutrient levels and algal blooms can also cause problems in drinking water in communities nearby and upstream from dead zones. Harmful algal blooms release toxins that contaminate drinking water, causing illnesses for animals and humans.

Why are dead zones bad?

Dead zones are the most severe result of eutrophication. This dramatic increase in previously limited nutrients causes massive algal blooms. These “red tides” or Harmful Algal Blooms can cause fish kills, human illness through shellfish poisoning, and death of marine mammals and shore birds.

What human activity causes dead zones?

What Causes Dead Zones? Dead zones are caused by excessive nitrogen and phosphorous pollution from human activities, including: Agricultural runoff from farmland that carries nutrients from fertilizers and animal manure into rivers and streams, eventually flowing into the Chesapeake Bay.