Category Archives: Cyanobacteria revisited

Bluegreen “Algae,”   Pink Flamingos, Red Tides, (and Nonpolluting Buses)


Not many plants have a more diversified story than Cyanobacteria.  We know them in Florida as villians of “toxic algal bloom” news, featured even in the gubernatorial race.    That horror story is not my focus today.  Google will unleash that mess abundantly already.  Quickly, however, toxic “algae” blooms are not limited to the Florida Active Adult Lifestyle.  Ask the residents of Toledo who drink Lake Erie, or what’s left  of my home town, Wheeling, W.Va. where “a green paint spill” reported in the Ohio River turned out to be Cyanobacteria.  The problem is global, making it tough to point the finger of blame too ardently at any particular political entity, or demanding simplistic politicized “do something.”


Now hear this!…bluegreen “algae” are not algae.  They are Cyanobacteria. Even though the term “algae” is vague, Cyanobacteria are no more algae than I am.  They are large photosynthetic bacteria.

Cyanobacteria or similar paleo-germs are contenders to be the oldest life on Earth.  The globe is about 4.5 billion years old, with Cyanobacterial evidence extending back over 3.5 billion years.   Contrast that with humans, here for maybe 2 million years.    So then Cyanos are some 2000 times older than we are.  We curse them for polluting rivers, yet, looking back a few billenia, who kickstarted  the biological world with original oxygen?

BGA from fish tankCLOSE2

And even better, who makes the Flamingos pink?   With variation from species to species and from place to place, in a general sense Flamingo pink coloration owes mostly to pigments from Cyanobacteria, including the genus Spirulina on sale now in a health food store as a dietary aid.   I wonder if Spirulina over-consumption will give a ruddy glow.  (Just kidding.)

What about those pink Roseate Spoonbillls John and I witnessed today in Riverbend Park? They are more carnivorous than Flamingos, and their rosy pigments come from the little creatures they catch in their spoons, although ultimately the pink ink comes from plankton, presumably Cyanobacteria and perhaps also true Algae.  In the Spoonbill’s case, the path to pink may be complex.

CLICK HERE for quick peek at some Spoonbill Action!

Cyanobacteria have astounding grit.   They grow on trees, on rocks, on my back porch, on wet concrete, and mostly in salt and fresh water, where we may try to suppress them with shade.  Shade doesn’t work; some species cope by using cells called akinetes (AY-kuh-neats) able to sink and wait out bad times.

Many Cyanobacteria, especially planktonic species, including the Microcystis in toxic blooms,   have “air bladders.”  When the cell is near the sunny water surface photosynthesis there depletes buoyant carbon dioxide from the bladder and creates sinky heavy carbohydrates.  The cell thus loses buoyancy and sinks to deeper waters where there is less sun and more nutrients, such as phosphorus.   Down in the dark, the cell stocks up on nutrients, burns its heavy carbohydrates, generates carbon dioxide back into the bladder, and rises anew.  The yo-yo cycle is daily.


Lyngbya, with sheath

Fast growers demand much nitrogen.   Problem is, most plants can’t use nitrogen gas from the air.   Good thing we have Cyanobacteria with specialized cells called heterocysts to convert atmospheric nitrogen to ammonium fertilizer to their own benefit, to the benefit of plants that share their soil,  such as in Florida wet prairies, and to the benefit of many symbionts.

Cyanobacteria have more symbiotic relationships than you can shake an alga at.  They hook up with:  true algae, cycads, diatoms, ferns (including the floating fern Azolla used to fertilizer rice), flowering plants, fungi, hornworts, liverworts, marine worms, mosses (including Sphagnum), radiolarians, sea squirts, sponges by the dozen, and more, including partnerships awaiting discovery.  Oddly enough, if we shift our attention momentarily to the Red Tides befouling the beaches, those little agents of destruction are Dinoflagellate Algae, and guess what, Dinoflagellates and Cyanobacteria are known to have symbiotic relationships.   Every Cyanobacterial symbiosis has a story, but enough is enough for now.

Yet permit me one little example, the Southern-Hemisphere flowering plant genus Gunnera is unique so far as is known, having cyanobacteria living inside the host’s cells.   This growth-promoting intimacy is of interest in a hungry world, not merely because some Gunneras are food, but conceivably the little internal fertilizer generators could be extended to other crop plants.

Now for the surprise ending.  Not all Cyanobacteria are photosynthetic.  Recently in Spain some  turned up 2000 feet underground.   They get their energy from hydrogen just like a fuel cell.  Just think, the most primitive “plants”  of the deep past are demonstrating the most advanced energy form we know.


Photo by Donna Rogers


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