A phenomenon known as “red tide” appeared in the Thermaikos Gulf and across the shores of Thessaloniki, the second biggest city of Greece.
The sea has been discolored and turned into red.
Red Tide is a common name for a phenomenon known as an algal bloom (large concentrations of aquatic microorganisms) when it is caused by a few species of dinoflagellates and the bloom takes on a red or brown color.
Red tides are events in which estuarine, marine, or fresh water algae accumulate rapidly in the water column, resulting in coloration of the surface water. It is usually found in coastal areas.
These algae, a form of phytoplankton, are single-celled protists, plant-like organisms that can form dense, visible patches near the water’s surface.
Causes: The occurrence of red tides in some locations appears to be entirely natural (algal blooms are a seasonal occurrence resulting from coastal upwelling, a natural result of the movement of certain ocean currents), while in others they appear to be a result of increased nutrient loading from human activities.
Coastal water pollution produced by humans and systematic increase in sea water temperature have also been implicated as contributing factors in red tides.
According to local online media Seleo.gr, the phenomenon is not rare in Thessaloniki.
Apart from the unaesthetic aspect of the red tide, there is also a very strong unpleasant smell, Seleo.gr notes.
see also: Red Tide