what pigment is present in all photosynthetic organisms
Photosynthetic pigment


A photosynthetic pigment (accessory pigment; chloroplast pigment; antenna pigment) is a pigment that is present in chloroplasts or photosynthetic bacteria and captures the light energy necessary for photosynthesis. Plants pigments (in order of increasing polarity): Chlorophyll "a" is the most common of the six, present in every plant that performs photosynthesis. The reason that there are so many pigments is that each absorbs light more efficiently in a different part of the electromagnetic spectrum. well at a wavelength of about 400–450 nm and at 650–700 nm;
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Chlorophyll a


P680 and P700 are located. Chlorophyll "a" is essential for most photosynthetic organisms to release chemical energy but is not the only pigment that can be used for photosynthesis. All oxygenic photosynthetic organisms use chlorophyll "a", but differ in accessory pigments like chlorophyll "b". Chlorophyll "z" can also be found in very small quantities in the green sulfur bacteria, an anaerobic photoautotroph. These organisms use bacteriochlorophyll and some chlorophyll "a" but do not produce oxygen. Anoxygenic photosynthesis is the term applied to this
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Bacterial antenna complex


Bacterial antenna complex proteins are the main light-absorbing components in photosynthetic bacteria. Also known as a light-harvesting complex/system, the bacterial antenna complex is responsible for the transfer of solar energy to the photosynthetic reaction centre. The Inall photosynthetic bacteria have similar features. They consist of light-absorbing pigments that are either non-covalently associated with integral proteins in the case of purple photosynthetic bacteria and cyanobacteria, or present in chlorosomes in the case of green photosynthetic bacteria. The light-absorbing pigments in chlorosomes do not
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Metabolism


green sulfur bacteria can use sunlight as a source of energy, while switching between carbon fixation and the fermentation of organic compounds. In many organisms the capture of solar energy is similar in principle to oxidative phosphorylation, as it involves the storage of energy as a proton concentration gradient. This proton motive force then drives ATP synthesis. The electrons needed to drive this electron transport chain come from light-gathering proteins called photosynthetic reaction centres or rhodopsins. Reaction centers are classed into two types depending on the type of photosynthetic pigment present,
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Prochlorococcus


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. "Prochlorococcus" microbes are among the major primary producers in the ocean, responsible for a large percentage of the photosynthetic production of oxygen. Analysis of the genome sequences of 12 "Prochlorococcus" strains show that 1,100 genes are common to all strains, and the average genome size is about
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Prochlorophyta


Prochlorophyta is a group of photosynthetic bacteria, an important component of picoplankton. These oligotrophic organisms are abundant in nutrient poor tropical waters and use a unique photosynthetic pigment, divinyl-chlorophyll, to absorb light and acquire energy. Prochlorophyta lack red and blue phycobilin pigments and have stacked thylakoids, making them distinctly different from Cyanobacteria (or Cyanophyta), but some authors consider them as part of the Cyanobacteria, as the group Prochlorales. This unique group of phytoplankton, with no phycobilin pigments, were initially found in 1975 near the Great
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Photodissociation


cyanobacteria and the chloroplasts of green algae and plants. The conventional, semi-classical, model describes the photosynthetic energy transfer process as one in which excitation energy hops from light-capturing pigment molecules to reaction center molecules step-by-step down the molecular energy ladder. The effectiveness of photons of different wavelengths depends on the absorption spectra of the photosynthetic pigments in the organism. Chlorophylls absorb light in the violet-blue and red parts of the spectrum, while accessory pigments capture other wavelengths as well. The phycobilins of red
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Bacterioplankton


. Some Cyanobacteria are capable of nitrogen fixation.The genus "Anabaena" uses specialized cells called heterocysts to physically separate nitrogen fixation and photosynthesis. "Trichodesmium" is an example of cyanobacteria that is capable of fixing nitrogen through an alternative photosynthetic pathway. Other photosynthetic bacterioplankton, including purple and green bacteria, undergo anoxygenic photosynthesis in anaerobic conditions. The pigments synthesized in these organisms are sensitive to oxygen. In purple bacteria the major pigments include bacteriochlorophyll a and b and carotenoids. Green bacteria have different light harvesting pigments consisting of bacteriochlorophyll c
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Myxoxanthophyll


Myxoxanthophyll is a carotenoid glycoside pigment present (usually as rhamnosides) in the photosynthetic apparatus of cyanobacteria. It is named after the word ""Myxophyceae"", a former term for cyanobacteria. As a monocyclic xanthophyll, it has a yellowish color. It is required for normal cell wall structure and thylakoid organization in the cyanobacterium "Synechocystis". The pigment is unusual because it is glycosylated on the 2'-OH rather than the 1'-OH position of the molecule. Myxoxanthophyll was first isolated from "Oscillatoria rubenscens" in 1936. The bright
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Bacterioplankton


donor, and the light harvesting pigments used for energy capture. Cyanobacteria are a large group of photosynthetic bacterioplankton, often growing as cells or in filamentous colonies. These organisms are the dominant group of bacterioplankton using oxygenic photosynthesis in aquatic ecosystems. Cyanobacteria, along with photosynthetic eukaryotes, are responsible for approximately half of the total global primary production making them key players in the food web. They use photosynthesis to generate energy in the form of organic compounds and produce oxygen as a byproduct. Major light harvesting pigments include chlorophylls, phycoerytherin,
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Antheraxanthin


Antheraxanthin (from "ánthos", Greek for "flower" and "xanthos", Greek for "yellow") is a bright yellow accessory pigment found in many organisms that perform photosynthesis. It is a xanthophyll cycle pigment, an oil-soluble alcohol within the xanthophyll subgroup of carotenoids. Antheraxanthin is both a component in and product of the cellular photoprotection mechanisms in photosynthetic green algae, red algae, euglenoids, and plants. Antheraxanthin is an intermediate molecule of the xanthophyll cycle in most photosynthetic eukaryotes, namely plants, and
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Photoprotection


chemical damage. When photosynthetic antenna pigments such as chlorophyll are excited by light absorption, unproductive reactions may occur by charge transfer to molecules with unpaired electrons. Because oxygenic phototrophs generate O as a byproduct from the photocatalyzed splitting of water (HO), photosynthetic organisms have a particular risk of forming reactive oxygen species. Therefore, a diverse suite of mechanisms have developed in photosynthetic organisms to mitigate these potential threats, which become exacerbated under high irradiance, fluctuating light conditions, in adverse environmental conditions such as cold or drought, and while
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Predatory dinoflagellate


Predatory dinoflagellates are predatory heterotrophic or mixotrophic alveolates that derive some or most of their nutrients from digesting other organisms. About one half of dinoflagellates lack photosynthetic pigments and specialize in consuming other eukaryotic cells, and even photosynthetic forms are often predatory. Organisms that derive their nutrition in this manner include "Oxyrrhis marina", which feeds phagocytically on phytoplankton, "Polykrikos kofoidii", which feeds on several species of red-tide and/or toxic dinoflagellates, "Ceratium furca", which is primarily photosynthetic but also capable of ingesting other protists such
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Ramlibacter tataouinensis


called superoxide dismutase. "Ramlibacter tataouinensis" possesses two forms of superoxide dismutase, one existing in the cytoplasm and the other in periplasm. "Ramlibacter tataouinensis" has genes encoding for carotenoid biosynthesis. Carotenoid are photosynthetic pigments usually found in chloroplasts of plants and in photosynthetic organisms like algae and fungus. These pigments assist in the transfer of light energy to the reactive centers during photosynthesis. Since "Ramlibacter tataouinensis" derives its energy from inorganic carbon compounds, the synthesis of carotenoids can be a means of quenching ROS. Three proteins may
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Photosynthesis


. These pigments are embedded in plants and algae in complexes called antenna proteins. In such proteins, the pigments are arranged to work together. Such a combination of proteins is also called a light-harvesting complex. Although all cells in the green parts of a plant have chloroplasts, the majority of those are found in specially adapted structures called leaves. Certain species adapted to conditions of strong sunlight and aridity, such as many "Euphorbia" and cactus species, have their main photosynthetic organs in their stems. The cells in
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Accessory pigment


Accessory pigments are light-absorbing compounds, found in photosynthetic organisms, that work in conjunction with chlorophyll "a". They include other forms of this pigment, such as chlorophyll "b" in green algal and higher plant antennae, while other algae may contain chlorophyll "c" or "d". In addition, there are many non-chlorophyll accessory pigments, such as carotenoids or phycobiliproteins, which also absorb light and transfer that light energy to photosystem chlorophyll. Some of these accessory pigments, in particular the carotenoids
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Chloroplast


in other gram-negative bacteria, and which is located between their two cell membranes. Like chloroplasts, they have thylakoids within. On the thylakoid membranes are photosynthetic pigments, including chlorophyll "a". Phycobilins are also common cyanobacterial pigments, usually organized into hemispherical phycobilisomes attached to the outside of the thylakoid membranes (phycobilins are not shared with all chloroplasts though). Somewhere around 1 to 2 billion years ago, a free-living cyanobacterium entered an early eukaryotic cell, either as food or as an internal parasite, but
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Bacterial antenna complex


associate with integral proteins for assembly. Green and purple photosynthetic bacteria utilize different bacteriochlorophyll molecules while cyanobacteria contain chlorophyll, the light-absorbing pigments found in plants. Purple photosynthetic bacteria, particularly "Rhodopseudomonos acidophilia" of purple non-sulfur bacteria, have been one of the main groups of organisms used to study bacterial antenna complexes so much is known about this group's photosynthetic components. In photosynthetic purple bacteria there are usually two antenna complexes that are generally composed of two types of polypeptides (alpha and beta chains). These proteins
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Heterotrophic theory


, according to Oparin, should have first appeared in evolution due to its simplicity. This was opposed to the idea, widely accepted at that time, that the first organisms emerged endowed with an autotrophic metabolism, which included photosynthetic pigments, enzymes and the ability to synthesize organic compounds from CO and HO; for Oparin it was impossible to reconcile the original photosynthetic organisms with the ideas of Darwinian evolution From the detailed analysis of the geochemical and astronomical data known at that date, Oparin also proposed a primitive atmosphere devoid of O and
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Algal bloom


can block the sunlight from reaching other organisms, deplete oxygen levels in the water, and some algae even secrete toxins into the water. Since 'algae' is a broad term including organisms of widely varying sizes, growth rates and nutrient requirements, there is no officially recognized threshold level as to what is defined as a bloom. For some species, algae can be considered to be blooming at concentrations reaching millions of cells per milliliter, while others form blooms of tens of thousands of cells per liter. The photosynthetic pigments in
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Light-harvesting complex


A light-harvesting complex has a complex of subunit proteins that may be part of a larger supercomplex of a photosystem, the functional unit in photosynthesis. It is used by plants and photosynthetic bacteria to collect more of the incoming light than would be captured by the photosynthetic reaction center alone. Light-harvesting complexes are found in a wide variety among the different photosynthetic species. The complexes consist of proteins and photosynthetic pigments and surround a photosynthetic reaction center to focus energy, attained from photons absorbed by the pigment, toward the reaction
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Lycopene


various "cis"-isomers constitute more than 60% of the total lycopene concentration, but the biological effects of individual isomers have not been investigated. Carotenoids like lycopene are found in photosynthetic pigment-protein complexes in plants, photosynthetic bacteria, fungi, and algae. They are responsible for the bright orange–red colors of fruits and vegetables, perform various functions in photosynthesis, and protect photosynthetic organisms from excessive light damage. Lycopene is a key intermediate in the biosynthesis of carotenoids, such as beta-carotene, and xanthophylls. Dispersed lycopene
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Photopigment


Photopigments are unstable pigments that undergo a chemical change when they absorb light. The term is generally applied to the non-protein chromophore moiety of photosensitive chromoproteins, such as the pigments involved in photosynthesis and photoreception. In medical terminology, "photopigment" commonly refers to the photoreceptor proteins of the retina. Photosynthetic pigments convert light into biochemical energy. Examples for photosynthetic pigments are chlorophyll, carotenoids and phycobilins. These pigments enter a high-energy state upon absorbing a photon which they can release in the form of chemical energy. This
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Bacterioplankton counting methods


bacterioplankton. Quantification of photosynthetic prokaryotes such as cyanobacteria and picoeukaryotic algae is made possible by the ability of photosynthetic pigments to fluoresce. For instance, the different formation of photosynthetic pigments in the two major photosynthetic prokaryotes, prochlorococcus and synechococcus, enable their very distinction. Prochlorococcus contains divynyl-chlorophylls "a" and "b" which display solely red fluorescence under excitation by blue or UV light, while synechococcus emits both orange and red fluorescence; orange from phycobilins and red from chlorophyll. Besides fluorescence, prochlorococcus and synechococus are of significantly
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Synechococcus


"Synechococcus" strains appear to be obligate photoautotrophs that are capable of supporting their nitrogen requirements using nitrate, ammonia, or in some cases urea as a sole nitrogen source. Marine "Synechococcus" species are traditionally not thought to fix nitrogen. The main photosynthetic pigment in "Synechococcus" is chlorophyll a, while its major accessory pigments are phycobilliproteins. The four commonly recognized phycobilins are phycocyanin, allophycocyanin, allophycocyanin B and phycoerythrin. In addition "Synechococcus" also contains zeaxanthin but no diagnostic pigment for this organism is known. Zeaxanthin
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Photosynthetically active radiation


take place. Other living organisms, such as cyanobacteria, purple bacteria, and heliobacteria, can exploit solar light in slightly extended spectral regions, such as the near-infrared. These bacteria live in environments such as the bottom of stagnant ponds, sediment and ocean depths. Because of their pigments, they form colorful mats of green, red and purple. Chlorophyll, the most abundant plant pigment, is most efficient in capturing red and blue light. Accessory pigments such as carotenes and xanthophylls harvest some green light and pass it
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Photosynthesis


membrane protein complexes of the photosynthetic system. Plants absorb light primarily using the pigment chlorophyll. The green part of the light spectrum is not absorbed but is reflected which is the reason that most plants have a green color. Besides chlorophyll, plants also use pigments such as carotenes and xanthophylls. Algae also use chlorophyll, but various other pigments are present, such as phycocyanin, carotenes, and xanthophylls in green algae, phycoerythrin in red algae (rhodophytes) and fucoxanthin in brown algae and diatoms resulting in a wide variety of colors
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Isopora palifera


live within the tissues of the coral polyps. These photosynthetic algae use sunlight to create organic compounds and the coral is able to use these to provide part of its nutritional needs. Fluorescent granules of pigment are present in the tissues and these are in greater concentrations in individuals growing in high-light environments. "Isopora palifera" closely resembles "Isopora cuneata", and often has similar forms of growth, but "I. cuneata" mostly occurs in more eastern parts of the Pacific and in shallower water, and the holes in
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Plastid evolution


A plastid is a membrane-bound organelle found in plants, algae and other eukaryotic organisms that contribute to the production of pigment molecules. Most plastids are photosynthetic, thus leading to color production and energy storage or production. There are many types of plastids in plants alone, but all plastids can be separated based on the number of times they have undergone endosymbiotic events. Currently there are three types of plastids; primary, secondary and tertiary. Endosymbiosis is reputed to have led to the evolution of eukaryotic organisms today, although the
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Cyanotoxin


green algae". Traditionally they were thought of as a form of algae, and were introduced as such in older textbooks. However modern sources tend to regard this as outdated; they are now considered to be more closely related to bacteria, and the term for true "algae" is restricted to eukaryotic organisms. Like true algae, cyanobacteria are photosynthetic and contain photosynthetic pigments, which is why they are usually green or blue. Cyanobacteria are found almost everywhere; in oceans, lakes and rivers as well as on land.
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Chlorophyll a


a" absorbs light within the violet, blue and red wavelengths while mainly reflecting green. This reflectance gives chlorophyll its green appearance. Accessory photosynthetic pigments broaden the spectrum of light absorbed, increasing the range of wavelengths that can be used in photosynthesis. The addition of chlorophyll "b" next to chlorophyll "a" extends the absorption spectrum. In low light conditions, plants produce a greater ratio of chlorophyll "b" to chlorophyll "a" molecules, increasing photosynthetic yield. Absorption of light by photosynthetic pigments converts photons into
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Biological pigment


binding of the chromogen and the protein subunits. For example, the blue carotenoprotein, linckiacyanin has about 100-200 carotenoid molecules per every complex. In addition, the functions of these pigment-protein complexes also change their chemical structure as well. Carotenoproteins that are within the photosynthetic structure are more common, but complicated. Pigment-protein complexes that are outside of the photosynthetic system are less common, but have a simpler structure. For example, there are only two of these blue astaxanthin-proteins in the jellyfish, "
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Chromera velia


when describing organelles of apparent algal descent in any protist, but that lack any chlorophyll or light absorbing pigment. Those found in apicomplexan parasites are a prominent example. The majority of members of the apicomplexan lineage still contain a genome in the plastid, indicating the organelle of the lineage's ancestors was once photosynthetic, but these plastids have no light absorbing pigments or light reaction machinery. While "Chromera velia" contains a photosynthetic plastid, the majority of apicomplexan relatives contain a non-photosynthetic plastid, and the remainder contain no plastid
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Chlorosome


A Chlorosome is a photosynthetic antenna complex found in green sulfur bacteria (GSB) and some green filamentous anoxygenic phototrophs (FAP) (Chloroflexaceae, Oscillochloridaceae; both members of Chlorflexia). They differ from other antenna complexes by their large size and lack of protein matrix supporting the photosynthetic pigments. Green sulfur bacteria are a group of organisms that generally live in extremely low-light environments, such as at depths of 100 metres in the Black Sea. The ability to capture light energy and rapidly deliver it to where it needs to
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Chlorophyll c


Chlorophyll "c" is a form of chlorophyll found in certain marine algae, including the photosynthetic Chromista (e.g. diatoms, brown algae) and dinoflagellates. It has a blue-greenish color and is an accessory pigment, particularly significant in its absorption of light in the 447-452 nm wavelength region, Like chlorophyll a and chlorophyll b, it helps the organism gather light and passes a quanta of excitation energy through the light harvesting antennae to the photosynthetic reaction centre. Chlorophyll "c" is unusual because it has a porphyrin
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Archaeplastida


date, it is not possible to confirm or refute alternative evolutionary scenarios to a single primary endosymbiosis. Photosynthetic organisms with plastids of different origin (such as brown algae) do not belong to the Archaeplastida. The archaeplastidans fall into two main evolutionary lines. The red algae are pigmented with chlorophyll "a" and phycobiliproteins, like most cyanobacteria, and accumulate starch outside the chloroplasts. The green algae and land plants – together known as Viridiplantae (Latin for "green plants") or Chloroplastida – are pigmented with chlorophylls "a
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Arrhenia


Arrhenia is a genus of fungi in the family Hygrophoraceae. "Arrhenia" also includes species formerly placed in the genera "Leptoglossum" and "Phaeotellus" and the lectotype species itself has an unusual growth form that would not normally be called agaricoid. All of the species grow in association with photosynthetic cryptogams such as mosses, including peat moss, and alga scums on decaying wood, and soil crusts consisting of mixes of such organisms. Typically the fruitbodies of "Arrhenia" species are grey to black or blackish brown, being pigmented
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Microbial metabolism


structures called chlorosomes (Green sulfur and non-sulfur bacteria), or the cytoplasmic membrane itself (heliobacteria). Different photosynthetic bacteria also contain different photosynthetic pigments, such as chlorophylls and carotenoids, allowing them to take advantage of different portions of the electromagnetic spectrum and thereby inhabit different niches. Some groups of organisms contain more specialized light-harvesting structures (e.g. phycobilisomes in Cyanobacteria and chlorosomes in Green sulfur and non-sulfur bacteria), allowing for increased efficiency in light utilization. Biochemically, anoxygenic photosynthesis is very different from oxygenic
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Peridinin


Peridinin is a light-harvesting apocarotenoid, a pigment associated with chlorophyll and found in the peridinin-chlorophyll-protein (PCP) light-harvesting complex in dinoflagellates, best studied in "Amphidinium carterae". Peridinin is an apocarotenoid pigment that some organisms use in photosynthesis. Many photosynthetic dinoflagellates use peridinin, which absorbs blue-green light in the 470-550nm range, outside the range accessible to chlorophyll molecules. The peridinin-chlorophyll-protein complex is a specialized molecular complex consisting of a boat-shaped protein molecule
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Light-dependent reactions


transmembrane proton gradient is used to make ATP via ATP synthase. The overall process of the photosynthetic electron transport chain in chloroplasts is: PS II is extremely complex, a highly organized transmembrane structure that contains a "water-splitting complex", chlorophylls and carotenoid pigments, a "reaction center" (P680), pheophytin (a pigment similar to chlorophyll), and two quinones. It uses the energy of sunlight to transfer electrons from water to a mobile electron carrier in the membrane called "plastoquinone": Plastoquinone, in
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Photosynthetic pigment


on to the chlorophylls. (Some cyanobacteria, the prochlorophytes, use chlorophyll b instead of phycobilin.) It is thought that the chloroplasts in plants and algae all evolved from cyanobacteria. Several other groups of bacteria use the bacteriochlorophyll pigments (similar to the chlorophylls) for photosynthesis. Unlike the cyanobacteria, these bacteria do not produce oxygen; they typically use hydrogen sulfide rather than water as the electron donor. Recently, a very different pigment has been found in some marine γ-proteobacteria: proteorhodopsin. It is similar to and
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Photosynthesis


dioxygen (O) molecule as a waste product. The overall equation for the light-dependent reactions under the conditions of non-cyclic electron flow in green plants is: Not all wavelengths of light can support photosynthesis. The photosynthetic action spectrum depends on the type of accessory pigments present. For example, in green plants, the action spectrum resembles the absorption spectrum for chlorophylls and carotenoids with absorption peaks in violet-blue and red light. In red algae, the action spectrum is blue-green light, which allows these
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Photosynthetic reaction centre


is used to excite an electron of a pigment. The free energy created is then used to reduce a chain of nearby electron acceptors, which have subsequently higher redox-potentials. These electron transfer steps are the initial phase of a series of energy conversion reactions, ultimately resulting in the conversion of the energy of photons to the storage of that energy by the production of chemical bonds. Reaction centers are present in all green plants, algae, and many bacteria. Although these species are separated by billions of years of evolution,
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Leucoplast


Leucoplasts (λευκός leukós "white", πλαστός plastós "formed, molded") are a category of plastid and as such are organelles found in plant cells. They are non-pigmented, in contrast to other plastids such as the chloroplast. Lacking photosynthetic pigments, leucoplasts are not green and are located in non-photosynthetic tissues of plants, such as roots, bulbs and seeds. They may be specialized for bulk storage of starch, lipid or protein and are then known as amyloplasts, elaioplasts, or proteinoplasts (also
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Red tide


, and estuaries, but they cannot thrive in freshwater environments. Certain species of phytoplankton and dinoflagellates found in red tides contain photosynthetic pigments that vary in color from brown to red. When the algae are present in high concentrations, the water may appear to be discolored or murky. The most conspicuous effects of red tides are the associated wildlife mortalities and harmful human exposure. The production of natural toxins such as brevetoxins and ichthyotoxins are harmful to marine life. Red tides occur naturally off coasts all over the world. Marine dinoflagellates
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Triparma


. The genus "Triparma" is actively studied because of their close relationship to the diatoms, and it has been discovered that they have different silica-limitation responses. While diatoms stop growing and cell division is inhibited under low-silica conditions, "Triparma" continues to grow and divide normally even under nanomolar concentrations of silica, although the silica plates are no longer produced. Photosynthetic pigments present in bolydophyte choroplasts include chlorophylls a, c, c, c, fucoxanthin, diatoxanthin, diadinoxanthin. The genus now includes all species
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Plant physiology


. Chlorophyll is the primary pigment in plants; it is a porphyrin that absorbs red and blue wavelengths of light while reflecting green. It is the presence and relative abundance of chlorophyll that gives plants their green color. All land plants and green algae possess two forms of this pigment: chlorophyll "a" and chlorophyll "b". Kelps, diatoms, and other photosynthetic heterokonts contain chlorophyll "c" instead of "b", red algae possess chlorophyll "a". All chlorophylls serve as the primary means plants use
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Dinoflagellate


The chloroplasts in most photosynthetic dinoflagellates are bound by three membranes, suggesting they were probably derived from some ingested algae. Most photosynthetic species contain chlorophylls "a" and c2, the carotenoid beta-carotene, and a group of xanthophylls that appears to be unique to dinoflagellates, typically peridinin, dinoxanthin, and diadinoxanthin. These pigments give many dinoflagellates their typical golden brown color. However, the dinoflagellates "Karenia brevis, Karenia mikimotoi," and "Karlodinium micrum" have acquired other pigments through endosymbiosis, including fucoxanthin. This suggests
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Light-dependent reactions


photosynthesis is: The two photosystems are protein complexes that absorb photons and are able to use this energy to create a photosynthetic electron transport chain. Photosystem I and II are very similar in structure and function. They use special proteins, called light-harvesting complexes, to absorb the photons with very high effectiveness. If a special pigment molecule in a photosynthetic reaction center absorbs a photon, an electron in this pigment attains the excited state and then is transferred to another molecule in the reaction center. This reaction, called photoinduced charge
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Thermophile


temperature optima occurs. Often, these organisms are colored, due to the presence of photosynthetic pigments. Thermophiles can be discriminated from mesophiles from genomic features. For example, the GC-content levels in the coding regions of some signatures genes were consistently identified as correlated with the temperature range condition when the association analysis was applied to mesophilic and thermophilic organisms regardless of their phylogeny, oxygen requirement, salinity, or habitat conditions. "Sulfolobus solfataricus" and "Sulfolobus acidocaldarius" are hyperthermophilic archaea. When these organisms are exposed to the
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Photosynthetic reaction centre


A photosynthetic reaction center is a complex of several proteins, pigments and other co-factors that together execute the primary energy conversion reactions of photosynthesis. Molecular excitations, either originating directly from sunlight or transferred as excitation energy via light-harvesting antenna systems, give rise to electron transfer reactions along the path of a series of protein-bound co-factors. These co-factors are light-absorbing molecules (also named chromophores or pigments) such as chlorophyll and phaeophytin, as well as quinones. The energy of the photon
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Terraforming of Venus


the carbon dioxide has already been removed. Although it is generally conceded that Venus could not be terraformed by introduction of photosynthetic biota alone, use of photosynthetic organisms to produce oxygen in the atmosphere continues to be a component of other proposed methods of terraforming. On Earth nearly all carbon is sequestered in the form of carbonate minerals or in different stages of the carbon cycle, while very little is present in the atmosphere in the form of carbon dioxide. On Venus, the situation is the opposite. Practically all of the carbon is
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Chloroplast


cytoplasm, even though they are nonphotosynthetic. Apicoplasts have lost all photosynthetic function, and contain no photosynthetic pigments or true thylakoids. They are bounded by four membranes, but the membranes are not connected to the endoplasmic reticulum. The fact that apicomplexans still keep their nonphotosynthetic chloroplast around demonstrates how the chloroplast carries out important functions other than photosynthesis. Plant chloroplasts provide plant cells with many important things besides sugar, and apicoplasts are no different—they synthesize fatty acids, isopentenyl pyrophosphate, iron-sulfur clusters, and carry out part of
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Mycosporine-like amino acid


high levels of reactive oxygen species. In these ecosystems, MAA-rich cyanobacteria may be providing antioxidant activity. MAAs are able to absorb UV light. A study published in 1976 demonstrated that an increase in MAA content was associated with an increase in photosynthetic respiration. Further studies done in marine cyanobacteria showed that the MAAs synthesized in response to UV-B correlated with an increase in photosynthetic pigments. Though not absolute proof, these findings do implicate MAAs as accessory pigments to photosynthesis. The eyes for the mantis shrimp contain four different
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Peridinin-chlorophyll-protein complex


structures. Photosynthetic dinoflagellates contain membrane-bound light-harvesting complexes similar to those found in green plants. They additionally contain water-soluble protein-pigment complexes that exploit carotenoids such as peridinin to extend their photosynthetic capacity. Peridinin absorbs light in the blue-green wavelengths (470 to 550 nm) which are inaccessible to chlorophyll by itself; instead the PCP complex uses the geometry of the relative pigment orientations to effect extremely high-efficiency energy transfer from the peridinin molecules to their neighboring chlorophyll molecule. PCP has served as a
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Chromoplast


Chromoplasts are plastids, heterogeneous organelles responsible for pigment synthesis and storage in specific photosynthetic eukaryotes. It is thought that like all other plastids including chloroplasts and leucoplasts they are descended from symbiotic prokaryotes. Chromoplasts are found in fruits, flowers, roots, and stressed and aging leaves, and are responsible for their distinctive colors. This is always associated with a massive increase in the accumulation of carotenoid pigments. The conversion of chloroplasts to chromoplasts in ripening is a classic example. They are generally found in mature tissues and are derived from preexisting
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Theodor Wilhelm Engelmann


highest concentration of oxygen. He concluded that the most photosynthetically active regions will have the highest concentrations of bacteria. The bacteria accumulated in the regions of red and violet light, showing that these wavelengths of light generated the most photosynthetic activity. However, his experiment was somewhat flawed because he used the sun as his light source. He failed to account for the fact that the sun does not emit all visible wavelengths of light at the same intensity. However, further analysis of plant pigments proved that his results were valid. A
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Argyropelecus affinis


, fish make short daily vertical migrations. Adult "Argyropelecus affinis" feed on planktonic organisms, salps, krill, arrow worms, copepods and ostracods. Smaller fish consume mainly copepods and ostracods, and their adult arrangement of photophores develop when they are about long. The lenses of the eyes of "A. affinis" contains yellow pigments that absorb short-wave radiation; the proportions of the two carotenoid-like pigments present change as the fish grows older. It is not clear what precise function is served by the pigments,
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Cytochrome b559


Cytochrome b559 is an important component of Photosystem II. PSII is a multisubunit protein-pigment complex containing polypeptides both intrinsic and extrinsic to the photosynthetic membrane. Within the core of the complex, the chlorophyll and beta-carotene pigments are mainly bound to the antenna proteins CP43 (PsbC) and CP47 (PsbB), which pass the excitation energy on to chlorophylls in the reaction centre proteins D1 (Qb, PsbA) and D2 (Qa, PsbD) that bind all the redox-active cofactors involved in the energy conversion process
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Carotenoid oxygenase


Carotenoid oxygenases are a family of enzymes involved in the cleavage of carotenoids to produce, for example, retinol, commonly known as vitamin A. This family includes an enzyme known as RPE65 which is abundantly expressed in the retinal pigment epithelium where it catalyzed the formation of 11-cis-retinol from all-trans-retinyl esters. Carotenoids such as beta-carotene, lycopene, lutein and beta-cryptoxanthine are produced in plants and certain bacteria, algae and fungi, where they function as accessory photosynthetic pigments and as scavengers of oxygen radicals for
17315266
Chloroplast membrane


, 15.5% phospholipids and 6.5% sulfolipids in spinach chloroplasts. The thylakoid membrane encloses a single, continuous aqueous compartment called the thylakoid lumen. These are the sites of light absorption and ATP synthesis, and contain many proteins, including those involved in the electron transport chain. Photosynthetic pigments such as chlorophylls a,b,c and some others, e.g., xanthophylls, carotenoids, phycobilins are also embedded within the granum membrane. With exception of chlorophyll a, all the other associated pigments are "accessory" and transfer energy to
8718804
Zooxanthellae


that partake in similar endosymbiotic relationships in both marine and freshwater habitats are green algae zoochlorellae. Zooxanthellae are photosynthetic organisms, which contain chlorophyll a and chlorophyll c, as well as the dinoflagellate pigments peridinin and diadinoxanthin. These provide the yellowish and brownish colours typical of many of the host species. During the day, they provide their host with the organic carbon products of photosynthesis, sometimes providing up to 90% of their host's energy needs for metabolism, growth and reproduction. In return, they receive nutrients, carbon dioxide,
14352893
Yellow


yellow and red organic pigments that are found in the chloroplasts and chromoplasts of plants and some other photosynthetic organisms like algae, some bacteria and some fungi. They serve two key roles in plants and algae: they absorb light energy for use in photosynthesis, and they protect the green chlorophyll from photodamage. In late summer, as daylight hours shorten and temperatures cool, the veins that carry fluids into and out of the leaf are gradually closed off. The water and mineral intake into the leaf is reduced, slowly at first,
15581716
Coral reef


corals that are pigmented with their own proteins) and is said to be bleached, a condition which, unless corrected, can kill the coral. There are eight clades of "Symbiodinium" phylotypes. Most research has been conducted on clades A–D. Each clade contributes their own benefits as well as less compatible attributes to the survival of their coral hosts. Each photosynthetic organism has a specific level of sensitivity to photodamage to compounds needed for survival, such as proteins. Rates of regeneration and replication determine the organism's ability to
5548029
Biological pigment


well-known UV-protector. Carotenoids and photopigments both indirectly act as photo-protective pigments, as they quench oxygen free-radicals. They also supplement photosynthetic pigments that absorb light energy in the blue region. It's known that animals use their color patterns to warn off predators, however it has been observed that a sponge pigment mimicked a chemical which involved the regulation of moulting of an amphipod that was known to prey on sponges. So whenever that amphipod eats the sponge, the chemical pigments prevents the moulting, and
18542137
Aerobic anoxygenic phototrophic bacteria


pigment that exists in AAPB is BChl a. Anaerobic phototrophic bacteria, on the contrary, can contain numerous species of photosynthetic pigments like bacteriochlorophyll a, b, c, d, e, f, etc. There is still a large void in the areas regarding the abundance and genetic diversity of the AAPB, as well as the environmental variables that regulate these properties. Research suggests that all currently known AAPB contain Gram-negative cell walls. The majority, have shapes that resemble cylinders, as well as flagella and cilia. AAPB
18867091
Photosynthetic reaction centre protein family


PsaB) making up a qausi-symmetrical 5-helical core complex with pockets for pigment binding. The two types are structually related and share a common ancestor. Each type have different pockets for ligands to accomendate their specific reactions: while Type I RCs use iron sulfur clusters to accept electrons, Type II RCs use quinones. The centre units of Type I RCs also have six extra transmembrane helices for gathering energy. The Type II photosynthetic apparatus in non-oxygenic bacteria consists of light-harvesting protein-pigment complexes LH1 and LH2,
16385181
Accessory pigment


broadened and flattened such that a wider range of visible and infrared radiation is absorbed by plants and algae. Most photosynthetic organisms do not absorb green light well, thus most remaining light under leaf canopies in forests or under water with abundant plankton is green, a spectral effect called the "green window". Organisms such as some cyanobacteria and red algae contain accessory phycobiliproteins that absorb green light reaching these habitats. In aquatic ecosystems, it is likely that the absorption spectrum of water, along with gilvin and tripton (dissolved and particulate
6692477
Photosynthetically active radiation


on to the photosynthetic process, but enough of the green wavelengths are reflected to give leaves their characteristic color. An exception to the predominance of chlorophyll is autumn, when chlorophyll is degraded (because it contains N and Mg) but the accessory pigments are not (because they only contain C, H and O) and remain in the leaf producing red, yellow and orange leaves. In land plants, leaves absorb mostly red and blue light in the first layer of photosynthetic cells because of Chlorophyll absorbance. Green light, however
222294
Orange (colour)


orange is azure – a colour that is one quarter of the way between blue and green on the colour spectrum. The actual complementary colour of true blue is yellow. Orange pigments are largely in the ochre or cadmium families, and absorb mostly greenish-blue light. (See also shades of orange). Other orange pigments include: The orange colour of carrots, pumpkins, sweet potatoes, oranges, and many other fruits and vegetables comes from carotenes, a type of photosynthetic pigment. These pigments convert the light energy that
20911665
Polyamines in plant stress


of their cationic nature (-) at physiological pH. This feature of polyamine makes it possible to interact with negatively charged macromolecules, stabilizing and protecting compounds under stress condition. These polyamines can bind to diverse types of proteins non-specifically, and this make it possible to the conjugation of polyamines to photosynthetic complexes and proteins is catalyzed by transglutaminase and leads to enhanced photosynthetic activity under stress conditions. Since polyamines perform essential roles for growth in all organisms, and most polyamine biosynthetic genes are present in at least two copies in plants,
5523910
Photosynthetic pigment


chlorophyll "b" at 450–500 nm and at 600–650 nm. Xanthophyll absorbs well at 400–530 nm. However, none of the pigments absorbs well in the green-yellow region, which is responsible for the abundant green we see in nature. Like plants, the cyanobacteria use water as an electron donor for photosynthesis and therefore liberate oxygen; they also use chlorophyll as a pigment. In addition, most cyanobacteria use phycobiliproteins, water-soluble pigments which occur in the cytoplasm of the chloroplast, to capture light energy and pass it
4839135
Isotope geochemistry


fractionated primarily by photosynthesis (Faure, 2004). The C/C ratio is also an indicator of paleoclimate: a change in the ratio in the remains of plants indicates a change in the amount of photosynthetic activity, and thus in how favorable the environment was for the plants. During photosynthesis, organisms using the C pathway show different enrichments compared to those using the C pathway, allowing scientists not only to distinguish organic matter from abiotic carbon, but also what type of photosynthetic pathway the organic matter was using. Occasional spikes
3905375
Myco-heterotrophy


such as some orchid species, that are non-photosynthetic and obligately myco-heterotrophic for part of their life cycle, and photosynthetic and facultatively myco-heterotrophic or non-myco-heterotrophic for the rest of their life cycle. Not all non-photosynthetic or "" plants are myco-heterotrophic – some non-photosynthetic plants like dodder directly parasitize the vascular tissue of other plants. In the past, non-photosynthetic plants were mistakenly thought to get food by breaking down organic matter in a manner similar to saprotrophic fungi
4087259
Biological pigment


(found in lettuce), and alpha carotene (found in carrots). In cyanobacteria, many other carotenoids exist such as canthaxanthin, myxoxanthophyll, synechoxanthin, and echinenone. Algal phototrophs such as dinoflagellates use peridinin as a light harvesting pigment. While carotenoids can be found complexed within chlorophyll-binding proteins such as the photosynthetic reaction centers and light-harvesting complexes, they also are found within dedicated carotenoid proteins such as the orange carotenoid protein of cyanobacteria. A particularly noticeable manifestation of pigmentation in plants is seen with autumn leaf color
18542117
Ornithocercus


the cytoplasm (approximately 3 µm in length and 0.25 µm), have been observed in "Ornithocercus" species. They’re thought to function in prey capture as trichocysts although no signs of emission have ever been observed. The observation of a cytosome with a microtubular strand was used as evidence of potential food uptake via the peduncle. "Ornithocercus" lacks photosynthetic pigments (and chloroplasts) and they are thus obligate heterotrophs. Along with other heterotrophic dinoflagellate genera, they were thought to exclusively feed through osmotrophy of dissolved organic manner.
13408038
Halobacterium


to its reddish hue as well. An optimal temperature for growth has been observed at 37 °C. "Halobacterium" may be a candidate for a life form present on Mars. One of the problems associated with the survival on Mars is the destructive ultraviolet light. These microorganisms develop a thin crust of salt that can moderate some of the ultraviolet light. Sodium chloride is the most common salt and chloride salts are opaque to short-wave ultraviolet. Their photosynthetic pigment, bacteriorhodopsin, is actually opaque to the longer-wavelength
14295722
Evolution of photosynthesis


and, in modified form, as the plastids of marine algae. Early photosynthetic systems, such as those from green and purple sulfur and green and purple nonsulfur bacteria, are thought to have been anoxygenic, using various molecules as electron donors. Green and purple sulfur bacteria are thought to have used hydrogen and sulfur as an electron donor. Green nonsulfur bacteria used various amino and other organic acids. Purple nonsulfur bacteria used a variety of nonspecific organic molecules. Fossils of what are thought to be filamentous photosynthetic organisms have been dated at
19060761
Photochemical Reflectance Index


The Photochemical Reflectance Index (PRI) is a reflectance measurement developed by John Gamon during his tenure as a postdoctorate fellow supervised by Christopher Field at the Carnegie Institution for Science at Stanford University. The PRI is sensitive to changes in carotenoid pigments (e.g. xanthophyll pigments) in live foliage. Carotenoid pigments are indicative of photosynthetic light use efficiency, or the rate of carbon dioxide uptake by foliage per unit energy absorbed. As such, it is used in studies of vegetation productivity and stress. Because the PRI measures plant responses to stress
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Orange (colour)


Orange is the colour between yellow and red on the spectrum of visible light. Human eyes perceive orange when observing light with a dominant wavelength between roughly 585 and 620 nanometres. In painting and traditional colour theory, it is a secondary colour of pigments, created by mixing yellow and magenta. It is named after the fruit of the same name. The orange colour of carrots, pumpkins, sweet potatoes, oranges, and many other fruits and vegetables comes from carotenes, a type of photosynthetic pigment. These pigments convert the light
20911642
Chloroplast


. Some contain pyrenoids. Rhodoplasts have chlorophyll "a" and phycobilins for photosynthetic pigments; the phycobilin phycoerytherin is responsible for giving many red algae their distinctive red color. However, since they also contain the blue-green chlorophyll "a" and other pigments, many are reddish to purple from the combination. The red phycoerytherin pigment is an adaptation to help red algae catch more sunlight in deep water—as such, some red algae that live in shallow water have less phycoerytherin in their rhodoplasts, and can appear more greenish
6481754
Microbial mat


, argues that, if one did not know their age, one would classify some of the fossil organisms in Australian stromatolites from as cyanobacteria, which are oxygen-producing photosynthesizers. There are several different types of photosynthetic reaction, and analysis of bacterial DNA indicates that photosynthesis first arose in anoxygenic purple bacteria, while the oxygenic photosynthesis seen in cyanobacteria and much later in plants was the last to evolve. The earliest photosynthesis may have been powered by infra-red light, using modified versions of pigments whose original function was to detect
3661172
Photosynthesis


Some organisms employ even more radical variants of photosynthesis. Some archaea use a simpler method that employs a pigment similar to those used for vision in animals. The bacteriorhodopsin changes its configuration in response to sunlight, acting as a proton pump. This produces a proton gradient more directly, which is then converted to chemical energy. The process does not involve carbon dioxide fixation and does not release oxygen, and seems to have evolved separately from the more common types of photosynthesis. In photosynthetic bacteria, the proteins that gather light for photosynthesis
4838984
Chloroplast


Chloroplasts are organelles that conduct photosynthesis, where the photosynthetic pigment chlorophyll captures the energy from sunlight, converts it, and stores it in the energy-storage molecules ATP and NADPH while freeing oxygen from water in plant and algal cells. They then use the ATP and NADPH to make organic molecules from carbon dioxide in a process known as the Calvin cycle. Chloroplasts carry out a number of other functions, including fatty acid synthesis, much amino acid synthesis, and the immune response in plants. The number of chloroplasts per cell varies
6481740
June Lascelles


pre-molecular genetics to the biosynthesis of the photosynthetic pigments called bacteriochlorophyll. She was awarded her D.Phil in 1952, and continued her work at Oxford. In 1956, Lascelles was awarded a Rockefeller Foundation fellowship, and went to Stanford University for a year to work with C. B. van Niel at the Hopkins Marine Station at Pacific Grove, California. Van Niel was legendary in his knowledge of microorganism biology, and this experience afforded Lascelles a great deal, especially the ability to study more exotic bacterial organisms. She worked at dispelling
9785274
Purple Earth hypothesis


regions of the solar spectrum. The simplicity of haloarchaeal retinal pigments in comparison to the more complex chlorophyll-based photosynthetic membrane, their association with isoprenoid lipids in the cell membrane, as well as the discovery of archaeal membrane components in ancient sediments on the early Earth are consistent with an early appearance of life forms with purple membrane prior to green photosynthesis. Co-existence of purple and green pigment containing microorganisms in many environments suggests their co-evolution. Astrobiologists have suggested that retinal pigments may serve as remote biosignatures in exoplanet research
16732927
Emmett Chappelle


famous for designing airplanes and spacecraft. There, Chappelle made a major discovery that has largely contributed to the knowledge of bacteria, cyanobacteria, and other single-celled organisms around the world. He discovered that even single-celled organisms such as algae, are photosynthetic, meaning they are able to convert carbon dioxide to oxygen. This ability to photosynthesize atmospheric carbon dioxide to oxygen is characteristic of all plants that is the opposite process of cellular respiration, that all animals and non-photosynthetic organism rely on to sustain life. Both
5730536
Plastid terminal oxidase


cells. PTOX is also thought to determine the redox poise of the developing photosynthetic apparatus and without it, plants fail to assemble organized internal membrane structures in chloroplasts when exposed to high light during early development. Plants deficient in the "IMMUTANS" gene that encodes the oxidase are especially susceptible to photooxidative stress during early plastid development. The knockout plants exhibit a phenotype of variegated leaves with white patches that indicate a lack of pigmentation or photodamage. This effect is enhanced with increased light and temperature during plant development. The lack of plastid
9873462
Nelumbo


rapid and dramatic increase in photosystems, photosynthetically involved pigments, electron transport rates, and the presence of 13 in the receptacle and petals, all of which assist in increasing photosynthesis rates. After this transition, all thermogenesis in the flower is lost. Pollinators do not need to be attracted once the ovary is fertilized, and thus the receptacle's resources are better used when it is photosynthesizing to produce carbohydrates that can be put toward plant biomass or fruit mass. Other plants that utilize thermoregulation in their life cycles are the eastern skunk
18018762
Browsing (herbivory)


, which have all photosynthetic tissues and reproductive organs at the apex of a singular stem. This means that a deer may eat all the reproductive and photosynthetic tissues at once, reducing the plant’s height, photosynthetic capabilities, and reproductive output. This is one example of how overbrowsing can lead to the loss of reproductive individuals in a population, and a lack of recruitment of young plants. Plants also differ in their palatability to herbivores. At high densities of herbivores, plants that are highly selected as browse may be missing small
6513489
PI curve


individuals vary in size, it is also useful to normalise C concentration to Chlorophyll a (an important photosynthetic pigment) to account for specific biomass. As far back as 1905, marine researchers attempted to develop an equation to be used as the standard in establishing the relationship between solar irradiance and photosynthetic production. Several groups had relative success, but in 1976 a comparison study conducted by Alan Jassby and Trevor Platt, researchers at the Bedford Institute of Oceanography in Dartmouth, Nova Scotia, reached a conclusion that solidified the way in which
1690228
Chimera (genetics)


that part of the plant tissue has no green pigment and no photosynthetic ability. This mutated tissue is unable to survive on its own but is kept alive by its partnership with normal photosynthetic tissue. Sometimes chimeras are also found with layers differing in respect of both their nuclear and their plastid genes. There are multiple reasons to explain the occurrence of plant chimera during plant recovery stage: (1) The process of shoot organogenesis starts form the multicellular origin. (2) The endogenous tolerance leads to the ineffectiveness of the weak selective
20590358
Vaucheria litorea


obtains its energy through photosynthesis taking place in chloroplasts. The chloroplasts of "V. litorea" contain the photosynthetic pigments Chlorophyll a, Chlorophyll c, β-Carotene, and the carotenoid diadinoxanthin. "V. litorea" are consumed by the sea slug "Elysia chlorotica", but are only partially digested by them in order to retain the photosynthetic chloroplasts in a process called kleptoplasty. The sea slug feeds on "V. litorea", retaining the chloroplasts in storage in cells along the slug's digestive tract. The chloroplasts continue to photosynthesize
779540
Photosynthetic picoplankton


divide all at the same time at the end of the day. This synchronization could be due to the presence of an internal biological clock. In the 2000s, genomics allowed to cross a supplementary stage. Genomics consists in determining the complete sequence of genome of an organism and to list every gene present. It is then possible to get an idea of the metabolic capacities of the targeted organisms and understand how it adapts to its environment. To date, the genomes of several types of "Prochlorococcus" and "Synechococcus",
11178075
Tropical salt pond ecosystem


used to produce components used in highly technological processes. Photosynthetic pigment found in "Halobacterium halobium" is produced commercially and used for optical data processing, non-linear optics and as light sensors. Halophilic bacteria could also be used to produce polyhydroxyalkanoates (PHA) which are biodegradable, water resistant thermoplastics. Both anthropogenic and natural threats affect tropical salt ponds. Natural threats include hurricanes and other large storms, salinity changes, runoff, sedimentation, and grazing and predation. Hurricanes and other large storms can damage salt pond organisms as well
12631580
Albinism


totally devoid of chlorophyll. Terms associated with this phenomenon are "hypochromia" and "albiflora". Biological pigments are substances produced by living organisms that have a colour resulting from selective colour absorption. What we perceive as "colour" are the wavelengths of light that are not absorbed by the pigment, but instead are reflected. Biological pigments include plant pigments and flower pigments. Animals can appear colored due to two mechanisms, pigments and structural colors. Animals may have both biological pigments and structural colors, for example, some butterflies
19261517
Bacteriochlorophyll


Bacteriochlorophylls (BChl) are photosynthetic pigments that occur in various phototrophic bacteria. They were discovered by C. B. van Niel in 1932. They are related to chlorophylls, which are the primary pigments in plants, algae, and cyanobacteria. Groups that contain bacteriochlorophyll conduct photosynthesis, but do not produce oxygen. They use wavelengths of light not absorbed by plants or Cyanobacteria. Replacement of Mg2+ with protons gives bacteriophaeophytin (BPh), the phaeophytin form. Bacteriochlorophylls "a", "b", and "g" are bacteriochlorins
1843815
Chloroflexi (class)


The Chloroflexia are one of six classes of bacteria in the phylum Chloroflexi, known as filamentous green non-sulfur bacteria. They produce energy from light and are named for their green pigment, usually found in photosynthetic bodies called chlorosomes. Chloroflexia are typically filamentous, and can move about through bacterial gliding. They are facultatively aerobic, but do not produce oxygen in the process of producing energy from light, or phototrophy. Additionally, Chloroflexia have a different method of phototrophy (photoheterotrophy) than true photosynthetic bacteria. Whereas most bacteria,
10950535
Picozoa


Picobiliphyta". Two studies published in 2011 found the hypothesis that biliphytes, or picobiliphytes, were photosynthetic was likely to be false. A 2011 study by an international team from the Monterey Bay Aquarium Research Institute, Dalhousie University and the Natural History Museum London found that cells in the Pacific Ocean did not have fluorescence indicative of photosynthetic pigments, and concluded "...biliphytes are likely not obligate photoautotrophs but rather facultative mixotrophs or phagotrophs, whereby transient detection of orange fluorescence could represent ingested prey items (e.g., the cyanobacterium Synechococcus)"
16864136
PI curve


population success; using the PI curve to elicit predictions of rate flux to environmental changes is useful for monitoring phytoplankton bloom dynamics and ecosystem stability. The second equation accounts for the phenomenon of photoinhibition. In the upper few meters of the ocean, phytoplankton may be subjected to irradiance levels that damage the chlorophyll-a pigment inside the cell, subsequently decreasing photosynthetic rate. The response curve depicts photoinhibition as a decrease in photosynthetic rate at light intensities stronger than those necessary for achievement of Pmax. Terms not included in the above equation are
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