Cyanobacteria

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Cyanobacteria

 
the blue-green bacteria (formerly called blue-green algae), a subgroup of the kingdom Procaryotae, unicellular or filamentous phototrophic organisms that use water as an electron donor and produce oxygen in the presence of light. They are the only organisms that fix both carbon dioxide (in the presence of light) and nitrogen. Most species are photosynthetic and many are strong nitrogen fixers. Several species are common causes of water pollution and are often used as indicators of eutrophication of lakes and streams.

Cy·a·no·bac·te·ri·a

(sī'ă-nō-bak-tēr'ē-ă),
A division of the kingdom Prokaryotae consisting of unicellular or filamentous bacteria that are either nonmotile or possess a gliding motility, reproduce by binary fission, and perform photosynthesis with the production of oxygen. These blue-green bacteria were formerly referred to as blue-green algae.
Synonym(s): Cyanophyceae

Cy·a·no·bac·te·ri·a

(sī'ă-nō-bak-tēr'ē-ă)
A division of the kingdom Prokaryotae consisting of unicellular or filamentous bacteria that are either nonmotile or possess a gliding motility, reproduce by binary fission, and perform photosynthesis with the production of oxygen.
Synonym(s): Cyanophyceae.

cyanobacteria (formerly blue-green algae)

a PHYLUM within the DOMAIN BACTERIA (see CLASSIFICATION). Cyanobacteria are a group of photosynthetic PROKARYOTES capable of OXYGENIC PHOTOSYNTHESIS. Some are also capable of ANOXYGENIC PHOTOSYNTHESIS. They were formerly called blue-green algae mainly because of the colour of many species, caused by a blue pigment called phycocyanin. They may also contain a red pigment called phycoerythrin. All members contain chlorophyll a. However, Prochloron additionally contains chlorophyll b (see CHLOROPHYLL). The cyanobacteria were possibly the first ORGANISMS on the earth to produce OXYGEN by photosynthesis. There is fossil evidence for their occurrence 3.5 x 109 years ago. The CELL WALL is analogous to that of Gram-negative BACTERIA (see GRAM'S STAIN and the LIGHT REACTIONS of photosynthesis occur on the THYLAKOID MEMBRANE system, within the cell. Other structures in the cell include carboxysomes, polyphosphate bodies as a PHOSPHATE reserve, and gas VACUOLES for buoyancy Some cyanobacteria are UNICELLULAR, others are filamentous (see FILAMENT (2)). They reproduce by fission or fragmentation. A number of species shows CELLULAR DIFFERENTIATION, with the formation of, for example, AKINETES, and specialized cells for NITROGEN FIXATION, called heterocysts. Cyanobacteria are widespread, being found in both terrestrial and aquatic environments that are illuminated. Some live in very inhospitable environments such as hot springs, where the temperature is in excess of 85 °C. They are responsible for much of the photosynthetic oxygen evolution in oceans and contribute to productivity through CARBON DIOXIDE fixation (see DARK REACTIONS) and NITROGEN FIXATION. Sometimes they accumulate in large numbers as BLOOMS on the surface of lakes, reservoirs and so on. These blooms may produce TOXINS.
References in periodicals archive ?
Vet Kathryn Claxton, fromWhite Cross Vets, which is part of the Independent Vetcare group, said: "There has been a significant increase in blue green algae cases this year across our practices -- and it seems to be happening earlier than other years too -- which may be due to the spells of very warm and very wet weather we have had.
There have been 39 suspected cases of blue green algae across the region since early June
The presence of blue green algae has been confirmed in water bodies across the country this summer.
"We have not had any previous reports of blue green algae in the pond at East Cramlington, and as algal blooms are more commonly associated with warm conditions it is particularly unusual to get an outbreak this early in the year.
Dai Walters, from Environment Agency Wales, said: "Our officers have been monitoring the lake very closely since we first identified the presence of blue green algae last month.
Yesterday a Wrexham council spokeswoman said: "Following tests by the Environment Agency on behalf of Wrexham County Borough Council a bloom of Blue Green Algae has been detected at Acton Park lake.
Blue green algae are generally found in water, such as ponds, and can cause fatal poisoning to pets, although not all species are toxic.
Blue green algae can cause allergic reactions including itchy and irritated eyes and skin and hay fever like symptoms.
It is sold in health food stores as blue green algae. Its supporters claim health benefits, including increased energy, improved memory, greater mental clarity and focus, improved digestion, control of appetite and cravings, heightened immune function, and relief from fatigue, hypoglycemia, PMS, anxiety and depression.
Blue green algae occurs naturally in lakes, rivers and ponds during the summer months every year and is not always toxic.
But organisers acting on the advice of health and safety experts cancelled the event due to the presence of blue green algae.