Blue-green algae bloom found in Lake Harriet 01:40. ... Despite the name, blue-green algae can be many colors and can look like spilled paint on the surface of the water.

In 2022, 19 blue-green algae advisories were issued in Rhode Island. The same number was issued in 2021, and there were 17 in 2020, 14 in 2019, and 16 in 2018, according to RIDEM stats.

During a bloom, the water becomes less clear and may look green, blue-green or greenish-brown. Scums can form during calm weather when several bloom forming species rise to the surface.