Why is the water brown at some Tampa Bay area beaches?

(Pinellas County)

TAMPA, Fla. (WFLA) — Beachgoers may notice something unusual about the water color at some Tampa Bay area beaches.

In Pinellas County, leaders said they have received numerous reports of discolored water at the beaches.

Some people reported seeing the brown water at Treasure Island, Madeira Beach and Redington Beach.

According to the Florida Fish and Wildlife Conservation Commission, the brown water is due to a bloom called “sea sawdust.”

“Sea sawdust,” also known as Trichodesmium, blooms every year in the Gulf of Mexico, FWC said. The blooms can extend for miles and even be seen from space.

Researchers have not documented any negative effects of Trichodesmium on marine life or people in Florida.

“Small blooms look like sawdust floating on the water surface, whereas larger blooms can look like oil slicks or foamy pollution. The amount of Trichodesmium on the surface may vary with time of day,” FWC said.

The blooms can appear brown when the blooms is healthy and green when the bloom is starting to decay. When the bloom starts to decay, it can smell similar to freshly cut hay, according to FWC.

The blooms usually happen between May and September, when iron-rich dust blows from the Sahara Desert in Africa across the Atlantic and settles in the Gulf of Mexico, officials said.