Algae are any of a large and diverse group of photosynthetic, eukaryotic organisms. The name is an informal term for a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular microalgae, such as Chlorella, Prototheca and the diatoms, to multicellular forms, such as the giant kelp, a large brown alga which may grow up to 50 metres (160 ft) in length. Most are aquatic and lack many of the distinct cell and tissue types, such as stomata, xylem and phloem that are found in land plants. The largest and most complex marine algae are called seaweeds. In contrast, the most complex freshwater forms are the Charophyta, a division of green algae which includes, for example, Spirogyra and stoneworts. Algae that are carried by water are plankton, specifically phytoplankton.
Cyanobacteria, also called Cyanobacteriota or Cyanophyta, are a phylum of autotrophic gram-negative bacteria that can obtain biological energy via oxygenic photosynthesis. The name "cyanobacteria" refers to their bluish green (cyan) color, which forms the basis of cyanobacteria's informal common name, blue-green algae, although as prokaryotes they are not scientifically classified as algae.
The lesser flamingo is a species of flamingo occurring in sub-Saharan Africa and western India. Birds are occasionally reported from further north, but these are generally considered vagrants.
Spirulina is the dried biomass of cyanobacteria that can be consumed by humans and animals. The three species are Arthrospira platensis, A. fusiformis, and A. maxima.
Phycobilins are light-capturing bilins found in cyanobacteria and in the chloroplasts of red algae, glaucophytes and some cryptomonads. Most of their molecules consist of a chromophore which makes them coloured. They are unique among the photosynthetic pigments in that they are bonded to certain water-soluble proteins, known as phycobiliproteins. Phycobiliproteins then pass the light energy to chlorophylls for photosynthesis.
Chlorella is a genus of about thirteen species of single-celled green algae of the division Chlorophyta. The cells are spherical in shape, about 2 to 10 μm in diameter, and are without flagella. Their chloroplasts contain the green photosynthetic pigments chlorophyll-a and -b. In ideal conditions cells of Chlorella multiply rapidly, requiring only carbon dioxide, water, sunlight, and a small amount of minerals to reproduce.
Phycocyanin is a pigment-protein complex from the light-harvesting phycobiliprotein family, along with allophycocyanin and phycoerythrin. It is an accessory pigment to chlorophyll. All phycobiliproteins are water-soluble, so they cannot exist within the membrane like carotenoids can. Instead, phycobiliproteins aggregate to form clusters that adhere to the membrane called phycobilisomes. Phycocyanin is a characteristic light blue color, absorbing orange and red light, particularly 620 nm, and emits fluorescence at about 650 nm. Allophycocyanin absorbs and emits at longer wavelengths than phycocyanin C or phycocyanin R. Phycocyanins are found in cyanobacteria. Phycobiliproteins have fluorescent properties that are used in immunoassay kits. Phycocyanin is from the Greek phyco meaning “algae” and cyanin is from the English word “cyan", which conventionally means a shade of blue-green and is derived from the Greek “kyanos" which means a somewhat different color: "dark blue". The product phycocyanin, produced by Aphanizomenon flos-aquae and Spirulina, is for example used in the food and beverage industry as the natural coloring agent 'Lina Blue' or 'EXBERRY Shade Blue' and is found in sweets and ice cream. In addition, fluorescence detection of phycocyanin pigments in water samples is a useful method to monitor cyanobacteria biomass.
Algaculture is a form of aquaculture involving the farming of species of algae.
A raceway pond is a shallow artificial pond used in the cultivation of algae.
Aphanizomenon flos-aquae is a brackish and freshwater species of cyanobacteria of the genus Aphanizomenon found around the world, including the Baltic Sea and the Great Lakes.
Phycocyanobilin is a blue phycobilin, i.e., a tetrapyrrole chromophore found in cyanobacteria and in the chloroplasts of red algae, glaucophytes, and some cryptomonads. Phycocyanobilin is present only in the phycobiliproteins allophycocyanin and phycocyanin, of which it is the terminal acceptor of energy. It is covalently linked to these phycobiliproteins by a thioether bond.
Arthrospira is a genus of free-floating filamentous cyanobacteria characterized by cylindrical, multicellular trichomes in an open left-hand helix. A dietary supplement is made from A. platensis and A. maxima, known as spirulina. The A. maxima and A. platensis species were once classified in the genus Spirulina. Although the introduction of the two separate genera Arthrospira and Spirulina is now generally accepted, there has been much dispute in the past and the resulting taxonomical confusion is tremendous.
A soda lake or alkaline lake is a lake on the strongly alkaline side of neutrality, typically with a pH value between 9 and 12. They are characterized by high concentrations of carbonate salts, typically sodium carbonate, giving rise to their alkalinity. In addition, many soda lakes also contain high concentrations of sodium chloride and other dissolved salts, making them saline or hypersaline lakes as well. High pH and salinity often coincide, because of how soda lakes develop. The resulting hypersaline and highly alkalic soda lakes are considered some of the most extreme aquatic environments on Earth.
Apophlaea is a genus of thalloid algae that is endemic to New Zealand. Species in the genus are found in the high intertidal zone on New Zealand's coasts. Specimens can reach around 15 cm in size. The thalli take a crustose form, but also contain upright, branching frond-like protrusions that reach 5–8 cm in height. Secondary pit connections and secondary pit connectionsare present in the organisms. Apophlaea reproduces by means of conceptacles; it produces tetraspores.
Microalgae or microscopic algae grow in either marine or freshwater systems. They are primary producers in the oceans that convert water and carbon dioxide to biomass and oxygen in the presence of sunlight.
Arthrospira platensis is a filamentous, gram-negative cyanobacterium. This bacterium is non-nitrogen-fixing photoautotroph. It has been isolated in Chenghai Lake, China, soda lakes of East Africa, and subtropical, alkaline lakes.
Spirulina ardissoni is a cyanobacteria from the family Microcoleaceae.
Phycotechnology refers to the technological applications of algae, both microalgae and macroalgae.
Avigad Vonshak is a Professor Emeritus at the French Associates Institute for Agriculture and Biotechnology of Drylands at the Jacob Blaustein Institutes for Desert Research at Ben-Gurion University of the Negev, Israel.
