Algal blooms in Bednesti Lake, British Columbia, Canada, over recent years led researchers to look into how humans impact aquatic life. Overall what they found was a chain reaction, when a type of aquatic plant like a lily pad was removed, other plants disappeared too.
Researchers analyzed 16 human-caused disturbances and 10 natural disturbances to see how much of an impact people truly have on aquatic plant life. Researches found six of those having an impact on individual aquatic plants, so if there was a sandy beach they would tend not to see one type of plant, but you might see another type of plant.