Cyanobacteria Photos

Kingdom Monera: Division Cyanophyta

1. Cyanobacteria (and Liverworts) In Guatemala

A pyramid at the ancient Maya city of Tikal in Guatemala. The moist, limestone blocks are covered with a felty layer of dark cyanobacteria (Scytonema) and black lichens, mixed with bright green patches of mosses and liverworts.

Microscopic view (400x) of the cellular filaments of the cyanobacterium Scytonema. The filaments are composed of minute prokaryotic cells within a conspicuous outer sheath. A special cell called a heterocyst can be seen in the lower filament. In many cyanobacteria this is the site of nitrogen fixation where atmospheric nitrogen is converted into ammonia.

Close-up view of limestone block at the Maya pyramid of Tikal in Guatemala showing bright green patch of liverworts surrounded by a dark mass of cyanobacteria (Scytonema). The miniature, palm-like stalks on the liverworts are female reproductive structures called archegoniophores. There are probably some male antheridiophores mixed in with this dense population.

2. Other Examples of Cyanobacteria

Nostoc "balls" along the shore of a desiccated vernal pool in the Santa Rosa Plateau of Riverside County, California. Each gelatinous ball is composed of an aggregation of numerous filaments of cyanobacteria, each with bead-like strands of prokaryotic cells and heterocysts. Members of the genus Nostoc have been referred to as "star jelly," "witches' butter," and "mare's eggs." Balls of N. commune in wet meadows can be the size of a baseball. Dried Nostoc balls are sold in Asian markets. According to S. Facciola (Cornucopia II: A Sourcebook of Edible Plants, 1998) they are stir-fried, sautéed with oysters, and used in soups and as thickeners for other foods.

Fat Choy (Nostoc flagelliforme)

In Chinese cuisine, "fat choy" in Cantonese or "fa cai" in Mandarin refer to a black, hair-like vegetable served in China during festive seasons, such as the Chinese Lunar New Year. It is eaten as a vegetable primarily because "fat choy" reads the same as "strike a fortune," as one would find in Chinese greetings such as "kung hei fat choy" or "wishing you the luck to strike a fortune." This interesting vegetable comes from the black, hair-like strands of Nostoc flagelliforme (Nostocaceae), a terrestrial cyanobacterium native to northern China and other regions. Individual strands appear dull greenish when wet, but dried strands resemble black hair. A mass of strands is similar in size and shape to those of ordinary steel wool. Each macroscopic strand (visible to the naked eye) is actually composed of many microscopic, bead-like filaments of prokaryotic cells. This cyanobacterium grows very slowly in desert steppe and in arid and semi-arid regions of northern and northwestern China. According to Paul Pui-Hay But, et al. (2002), it forms a matlike growth that binds to the substrate.

Extensive harvesting of this cyanobacterium has seriously damaged its natural distribution, and further exploitation has been prohibited by the State Council of the People's Republic of China. When fat choy is removed from the ground, the surface soil is no longer bound together and is vulnerable to wind and water erosion. Uncontrolled harvesting of this valuable soil cyanobacterium has resulted in the desertification of large areas in northern China. Paul Pui-Hay But and his associates have found that fat choy sold in the marketplace is often adulterated with non-cellular strands of a starchy material. The starchy strands readily turn black in an iodine solution and are easily identified under a light microscope. Government restrictions on the harvesting of this cyanobacterium may be one of the reasons why fat choy for sale in markets has been adulterated with fillers.

Dried "fat choy" (Nostoc flagelliforme) packaged in cellophane and sold in an Asian market of San Diego County.

Macroscopic strands of fat choy (Nostoc flagelliforme) hydrated in water.

Microscopic view of a hydrated strand of "fat choy" (Nostoc flagelliforme) showing bead-like filaments of prokaryotic cells and several thick-walled heterocysts.

Microscopic view of a hydrated strand of "fat choy" (Nostoc flagelliforme) showing a bead-like filament of prokaryotic cells and a thick-walled heterocyst.

But, Paul Pui-Hay, Ling Cheng, Pui Kwan Chan, David Tai-Wai Lau and Joyce
Wing-Hin But. 2002. "Nostoc flagelliforme and Faked Items Retailed in Hong
Kong." Journal of Applied Phycology 14: 143-145.

The dried "black moss" imported from China and sold in Asian markets in San Diego County also appears to be Nostoc flagelliforme.

Size comparison between the strands of fat choy and ordinary steel wool.

Left: Colonies of mat-like cyanobacteria growing on the bottom of a bird bath. It took about one year for these cyanobacteria to become established in this new concrete bird bath. Right: Microscopic view (400x) of the prokaryotic filaments of cells. One filament has a distinct heterocyst at the end (red arrow). In many cyanobacteria this is the site of nitrogen fixation where atmospheric nitrogen is converted into ammonia.

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