cyanobacterium
Americannoun
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cyanobacteria
plural
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cyanobacteria
plural
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Any of a phylum of photosynthetic bacteria that live in water or damp soil and were once thought to be plants. Cyanobacteria have chlorophyll as well as carotenoid and phycobilin pigments, and they conduct photosynthesis in membranes known as thylakoids (which are also found in plant chloroplasts). Cyanobacteria may exist as individual cells or as filaments, and some species live in colonies. Many species secrete a mucilaginous substance that binds the cells or filaments together in colored (often bluish-green) masses. Cyanobacteria exist today in some 7,500 species, many of which are symbiotes, and have lived on Earth for 2.7 billion years. Since all species produce oxygen as a byproduct of metabolism, it is thought that much of Earth's atmospheric oxygen can be attributed to cyanobacteria. Many species can also fix nitrogen and so play an important role in the nitrogen cycle.
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Also called blue-green alga
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Significantly, the study also found evidence suggesting that far-red light photosynthesis can be gained by a cyanobacterium through horizontal gene transfer.
From Science Daily ● Nov. 28, 2023
The two are forever on the trail of these composite symbiotic organisms, which they describe in the book as “an intensive cooperation between a fungus and an alga or a cyanobacterium, and sometimes all three.”
From Seattle Times ● Nov. 22, 2021
Some 2 billion years ago, a single-celled organism in Earth’s primeval ocean engulfed a mitochondrion and a cyanobacterium — and, now able to generate energy and photosynthesize, shunted off to change the world.
From Nature ● Apr. 2, 2019
But Chisholm has found hidden complexity within Prochlorococcus, a cyanobacterium that is the smallest, most abundant photosynthesizing cell in the ocean—responsible for 5% of global photosynthesis, by some estimates.
From Science Magazine ● Mar. 9, 2017
Lichens are a symbiotic relationship between a fungus and a photosynthetic organism, usually an alga or cyanobacterium.
From Textbooks ● Apr. 25, 2013
Even today, cyanobacteria remain essential to life on Earth.
From Science Daily ● Apr. 20, 2026
Microbes living near cyanobacteria could have quickly absorbed the oxygen being released.
From Science Daily ● Feb. 18, 2026
Organisms living near cyanobacteria could have used this enzyme to rapidly consume small amounts of oxygen as it was produced.
From Science Daily ● Feb. 18, 2026
The beauty of the sky contrasts sharply with the water, sometimes blue, but often a murky green from cyanobacteria or stained black.
From BBC ● Jan. 29, 2026
"Understanding stress-responsive biosynthesis in extremophilic cyanobacteria may accelerate industrial biotechnology for natural pigment and antioxidant production," says Prof. Kageyama when describing the motivation behind the work.
From Science Daily ● Jan. 13, 2026
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
