cyanobacterium
Americannoun
plural
cyanobacteriaplural
cyanobacteria-
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
Other Word Forms
- cyanobacterial adjective
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
In tropical places such as Kenya, sunshine throughout the year helps microscopic photosynthesizers thrive, and the water’s high salinity and pH favors the growth of spirulina, a cyanobacterium that is the lesser flamingo’s primary food.
From Science Magazine • Apr. 12, 2024
Chloroplasts developed in the course of evolution when the ancestors of today's plant cells absorbed a photosynthetic cyanobacterium.
From Science Daily • Mar. 1, 2024
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
Lichens are a symbiotic relationship between a fungus and a photosynthetic organism, usually an alga or cyanobacterium.
From Textbooks • Apr. 25, 2013
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.
