Karenia brevis is a species of algae native to the Gulf of Mexico. Times when its growth becomes uncontrollable are called harmful algal blooms (formerly called “red tide events”), and they are often caused by increased nutrients in the water. These excessive nutrients come from watersheds and runoff that contain anthropogenic materials like fertilizer, and the phosphate and nitrogen in fertilizers catalyze the growth of algae. As population density in Florida increases, fertilizer runoff increases as well. Harmful algal bloom events are dangerous to both humans and the environment. Thick layers of algal growth on the water’s surface create “dead zones” where sunlight cannot penetrate the ecosystem below the surface. This results in the death of aquatic animals, and an increase of Karenia brevis close to the shore causes respiratory irritation in humans. I examined the relation between algal blooms and increased population density between 1953 and 2023 in coastal Southwest counties of Florida. I predicted that the increase in population density has increased severe harmful algal blooms. BIO 340 final projec
