Every beach along Mississippi's Gulf Coast is closed for swimming as the entire shoreline is now under the same water warning tied to a blue-green algae bloom. CBS Biloxi affiliate WLOX-TV reported that Pascagoula's two beach testing sites on the east and west stations joined a list of 19 other beaches Sunday morning.

The Mississippi Department of Environmental Quality (MDEQ) issued a statement saying the closures were mandated in Jackson County, which spans a sizable chunk of the Mississippi coastline, "due to a blue-green Harmful Algal Bloom (HAB) extending into those areas."

According to the Mississippi Clarion Ledger, all of Mississippi's 21 beaches have now been closed and the algal bloom is caused by the opening of the Bonnet Carre spillway in Louisiana, which has brought an "excessive amount of freshwater to the coastline." The spillway was partially opened to offset a rising Mississippi River that swelled due to an especially wet winter in the Mississippi Valley.

Hancock County supervisors recently adopted new rules for beach signs and flags to warn residents and visitors which areas of the beach are off limits to swimming and fishing. WLOX-TV

The spillway is expected to close mid-July. Experts believe its closure will prompt the algae bloom to quickly dissipate. "Once they close the structure, conditions will start to change pretty quickly," John Lopez told CBS New Orleans affiliate WWL-TV. Lopez works for the Lake Pontchartrain Basin Foundation, a conservation organization that monitors water conditions throughout the Gulf Coast region.

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Harmful agal bloom is when algae grows quickly on the surface of the water. Warmer waters that experience increases in sea surface temperature or a change in sea currents are susceptible to the bloom. According to the Centers for Disease Control and Prevention, a HAB can look like foam, scum or mats on the surface of water and can be different colors. HABs can produce toxins that have caused a variety of illnesses in people and animals. HABs can occur in warm fresh, marine or brackish waters with abundant nutrients and are becoming more frequent with climate change.

The algae can cause rashes, stomach cramps, nausea, diarrhea and vomiting and that people and their pets should avoid contact with the water, according to a statement from the MDEQ. The MDEQ and the Mississippi Department of Marine Resources will be analyzing samples from the waters.

The MDEQ did not give an indication of when the beach openings would resume but said the advisory "may be revised as sampling results dictate."