Algae turns lake pink in Romania due to increased temperature

This special colouration is caused by red-pigmented microorganisms, bacteria and algae that multiply under increased salinity and high temperatures. 

They are not dangerous to the environment nor to the renowned sapropelic mud in the lake, the only inconvenience is the unpleasant smell.

The pink film, covering parts of the salt-water lake shore, appeared recently after temperatures exceeded 30°C. Specialists say that the sulfur bacteria in Lake Techirghiol precipitate like pink dust on the light-exposed parts of algae and thus the water changes colour. 

This phenomenon occurs especially on shore, where salt concentrations are higher. For some tourists, the phenomenon is spectacular.

“It’s very beautiful, unique. I’ve been here before, but I haven’t seen it pink,” one woman visiting the lake told Euronews.

Specialists assure us that the phenomenon is not dangerous, on the contrary, it helps increase the quality of sapropelic mud in the lake. The only drawback is the smell caused by the algal bloom which will only last for a short period until temperatures drop.

“This pigment is a normal one, specific to salt lakes, to lakes with salt concentration and high temperature. Of course, in Africa, there are many such situations. And sometimes if you check the Himalayan salt, it is reddish” explained scientific researcher Adrian Bîlbă.

“The salt obtained by natural desalination under the sun goes through a stage of this kind of bacterial proliferation and turns a reddish colour.” 

Lake Techirghiol, renowned for its sapropelic mud, is highly sought after by tourists during this time of the year.

“Here we hope to get better, with mud and salt water. That’s how we put it and lay like this,” said a woman bathing in the lake.

The same lake also experienced an unusual climate-related phenomenon last year, when, due to a prolonged drought, the water retreated some 50 metres from the original shoreline.