The type of algae that causes brown tide is blooming again, covering parts of Great South, Moriches and Shinnecock bays in a coffee-colored haze.

The algae, Aureococcus anophagefferens, first appeared in May and was documented in area waters spanning from Jones Inlet to Shinnecock Bay.

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It appeared to dissipate at the end of July but, late last month, another bloom began in Great South Bay, according to Chris Gobler, an associate dean and professor at Stony Brook University’s School of Marine and Atmospheric Sciences.

By last week, concentrations of the algae were more than 1.1 million cells per milliliter, the highest densities recorded in the bay in October since the blooms began appearing in 1985.

Algae blooms flourish in shallow, poorly flushed and nitrogen-rich areas. High concentrations can cloud the water and deplete oxygen levels.

Brown tide does not pose a danger to human health, but it can be harmful to shellfish.