Brown foam seen at Brighton beach likely a type of algae

The swirling mass was spotted near a groyne on Sunday afternoon at Brighton beach by a photographer who was concerned as to what it was.

It comes after Brighton and Hove City Council issued a reminder that marine algae can often be “mistaken for sewage”.

Blue Planet Society, a marine conservation activist group, said its plankton scientist agreed that the brown mass “looks like a phaeocystis globosa phytoplankton bloom”.

A spokesman added: “They often occur after a period of heavy rainfall. It's also the right time of year with the increase in daylight hours and sunlight increase.

The algae at Brighton beach

“But the only way to be certain would be by looking under a microscope.”

The council reassured people last week that brown foam spotted near Southwick was actually “marine algae in a rapid stage of growth”.

There have not been any sewage dumps in Brighton according to Southern Water's BeachBuoy sewage map.

The council added: “It is composed of microscopic plant and animal plankton, not raw sewage. This is a natural process.

“After the spring equinox, when daylight hours and sunlight increase, the plant (and animal) plankton in the water column respond.

“The plant plankton photosynthesise and proliferate, the animal plankton responds in turn as the plant plankton is a food source.

“Eventually, the algae bloom dies off once the oxygen and nutrient levels in the water have been depleted.

“The various colours seen relate to the algae in various stages of growth. If there is an unpleasant smell, it is due to the algae having died and entered the stage of decomposition - think rotting vegetables.

“If the sunny conditions combine with southerly winds, the algae is ‘whipped up’ onto the surface and blown onto the coastline. This is what is seen and is sometimes mistaken for sewage.”