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The oldest undisputed evidence of cyanobacteria is dated to be 2.1 Ga ago, but there is some evidence for them as far back as 2.7 Ga ago. [27] Cyanobacteria might have also emerged 3.5 Ga ago. [173] Oxygen concentrations in the atmosphere remained around or below 0.001% of today's level until 2.4 Ga ago (the Great Oxygenation Event). [174]
In a reversal of the pattern on land, in the oceans, almost all photosynthesis is performed by algae and cyanobacteria, with a small fraction contributed by vascular plants and other groups. Algae encompass a diverse range of organisms, ranging from single floating cells to attached seaweeds. They include photoautotrophs from a variety of groups.
Photosynthesis (/ ˌ f oʊ t ə ˈ s ɪ n θ ə s ɪ s / FOH-tə-SINTH-ə-sis) [1] is a system of biological processes by which photosynthetic organisms, such as most plants, algae, and cyanobacteria, convert light energy, typically from sunlight, into the chemical energy necessary to fuel their metabolism.
Three major groups of organisms constitute photosynthetic picoplankton: Cyanobacteria belonging to the genus Synechococcus of a size of 1 μm (micrometer) were first discovered in 1979 by J. Waterbury [3] (Woods Hole Oceanographic Institution). They are quite ubiquitous, but most abundant in relatively mesotrophic waters.
In aquatic habitats, unicellular cyanobacteria are considered as an important group regarding abundance, diversity, and ecological character. [47] Unicellular cyanobacteria have spherical, ovoid, or cylindrical cells that may aggregate into irregular or regular colonies bound together by the mucous matrix ( mucilage ) secreted during the growth ...
Prochlorococcus is a genus of very small (0.6 μm) marine cyanobacteria with an unusual pigmentation (chlorophyll a2 and b2).These bacteria belong to the photosynthetic picoplankton and are probably the most abundant photosynthetic organism on Earth.
Primary nutritional groups are groups of organisms, divided in relation to the nutrition mode according to the sources of energy and carbon, needed for living, growth and reproduction. The sources of energy can be light or chemical compounds; the sources of carbon can be of organic or inorganic origin.
Chemical and geological evidence indicate that photosynthetic cyanobacteria existed about 2.6 billion years ago and anoxygenic photosynthesis had been taking place since a billion years before that. [1] Oxygenic photosynthesis was the primary source of free oxygen and led to the Great Oxidation Event roughly 2.4 to 2.1 billion years ago during ...