Synura - The golden algae

When we hear the word algae many of us associate that with the color green. And some algae like desmids, are in fact green. But there are a lot of different kinds of algae, and far from all of them are green. Some are red or red and green like haematococcus, some are blue-green like spirulina, while others are yellowish, brown, or even golden.

Golden algae, or chrysophytes, are a large group of algae. Like other algae they contain chlorophyll and carry out photosynthesis to produce energy. But in addition to the green chlorophyll the chrysophytes contain the pigment fucoxanthin which is responsible for their golden color. One of them is synura which are tiny colonies measuring only 20-30 microns in diameter. Synura are present in many freshwater habitats around the world, where they can be found in relatively small numbers. But in spring and fall when the water is cold, massive blooms of the synura colonies can occur like here. If a bloom is especially large, the water can acquire a brownish color and a fishy smell due to waste products from the algae’s metabolism.

Each cell in the colonies is equipped with two whip-like structures called flagella, allowing synura to move gracefully through the water. Together with an incredibly primitive form of an eye in each cell, the whole colony is able to move according to light to find the optimal place for photosynthesis.

Narrated video of the golden algae Synura viewed with brightfield microscopy at 

various magnifications (20x, 40x, and 60x objectives)