by Piter Kehoma Boll
Let’s return once more to the troublesome and neglected protists. This time I’m bringing you another tiny but beautiful alga, more precisely a golden alga. Its name is Dinobryon divergens and as usual there is no common name, so I invented one by simply translating the scientific name, thus I’ll call it the divergent dinobryon.
The divergent dinobryon is part of the class Chrysophyceae, commonly known as golden algae. Measuring about 50 µm in length, it lives in temperate lakes around the world and forms colonies composed of about 6 to 50 ovoid cells that are surrounded by a vase-like shell (lorica) of cellulose, as seen in the picture below.
During colony formation, an original cell divides and one of the two daughter cells slides to the opening of the lorica and starts to construct a new one. It starts by creating the base of the lorica, which has a funnel shape and is attached to the inner wall of the original lorica. With further divisions, the colony starts to grow in a tree-like form. And the most interesting part is that the cells have two flagella and use them to swim, pulling the whole colony through the water.
As with other golden algae, the divergent dinobryon produces an internal siliceous structure that is globose, hollow and has a single opening connecting to the outside. This structure is called a statospore or stomatocyst and allows the cell to enter a resting state (cyst). The statospore is an important structure to help distinguish different species of golden algae.
The divergent dinobryon is a mixotrophic organism, meaning that it feeds by photosynthesis and by ingesting food too, especially bacteria. Kind of an interesting fellow, don’t you think?
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Franke, W., & Herth, W. (1973). Cell and lorica fine structure of the chrysomonad alga, Dinobryon sertularia Ehr. (Chrysophyceae) Archiv für Mikrobiologie, 91 (4), 323-344 DOI: 10.1007/BF00425052
Herth, W. (1979). Behaviour of the chrysoflagellate alga, Dinobryon divergens, during lorica formation Protoplasma, 100 (3-4), 345-351 DOI: 10.1007/BF01279321
Karim, A., & Round, F. (1967). Microfibrils in the lorica of the freshwater alga Dinobryon New Phytologist, 66 (3), 409-412 DOI: 10.1111/j.1469-8137.1967.tb06020.x
Sandgren, C. (1981). Characteristics of sexual and asexual resting cyst (statospore) formation in Dinobryon cylindricum Imhof (Chrysophyta) Journal of Phycology, 17 (2), 199-210 DOI: 10.1111/j.1529-8817.1981.tb00840.x
Sheath, R., Hellebust, J., & Sawa, T. (1975). The statospore of Dinobryon divergens Imhof: Formation and germination in a subarctic lake Journal of Phycology, 11 (2), 131-138 DOI: 10.1111/j.1529-8817.1975.tb02760.x
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