chlorophyll in brown algae

The lack of iron in the open ocean limits phytoplankton growth 10. . [15][16] Besides fronds, there are the large in size parenchymatic kelps with three-dimensional development and growth and different tissues (meristoderm, cortex and medulla) which could be consider the trees of the sea. There are no known species that exist as single cells or as colonies of cells,[11] and the brown algae are the only major group of seaweeds that does not include such forms. There are several causes that can contribute to an algal bloom. However, you may visit "Cookie Settings" to provide a controlled consent. First, members of the group possess a characteristic color that ranges from an olive green to various shades of brown. One example is carotenoid, which is a brown pigment (and is found in brown algae which, similar to dinoflagellates, can cause an algal bloom). This reflects their different metabolic pathways. Algae are aquatic and often unicellular organisms that use photosynthesis in order to get energy/food. Organic carbon can be found in many different things including sugars (glucose = C6H12O6), plants and animals. The form of chlorophyll a which emits long-wavelength bands is unstable and is easily destroyed by mechanical treatment of the tissue or cells of brown algae and diatoms Action spectra of fluorescence showed that 530-560 nm-light, absorbed by fucoxanthin, contributed to the emissions at 690-695 nm and 705-715 nm at 196C. [12] Although not all brown algae are structurally complex, those that are typically possess one or more characteristic parts. This combination of characteristics is similar to certain modern genera in the order Laminariales (kelps). How long should you meditate as a Buddhist? A personal account can be used to get email alerts, save searches, purchase content, and activate subscriptions. Microscopic phytoplankton play some of the biggest roles in climate control, oxygen supply and food production. Register, Oxford University Press is a department of the University of Oxford. As they need light to photosynthesize, phytoplankton in any environment will float near the top of the water, where sunlight reaches 10. This pigment appears as a blue-green color and is what's known as an accessory pigment. These different combinations of . This cookie is set by GDPR Cookie Consent plugin. However, in any marine environment, phytoplankton populations vary not only by season but by region. Tides, flooding and currents all encourage higher nutrient levels in the photic zone 13. While any one phytoplankton only lives for a few days, a population boom can last for weeks under the right conditions 11. The use of H2O introduced free oxygen (O2) into the environment as a byproduct. Regardless of size or form, two visible features set the Phaeophyceae apart from all other algae. This can be seen in a daily cycle as oxygen levels fluctuate with light levels throughout the day. Just as in plants, the chlorophyll in algae has a stronger relative absorption than the other molecules. 17: Ulva is a genus of multicellular marine green algae that forms flat sheets of cells. Do not use an Oxford Academic personal account. Cyanobacteria are the only bacteria that contain chlorophyll A, a chemical required for oxygenic photosynthesis (the same process used by plants and algae) 1,14. In form, the brown algae range from small crusts or cushions[10] to leafy free-floating mats formed by species of Sargassum. Phycoerythrin reflects red light, and can be found in red algae and cyanobacteria. The cell wall consists of two layers; the inner layer bears the strength, and consists of cellulose; the outer wall layer is mainly algin, and is gummy when wet but becomes hard and brittle when it dries out. Alberte RS, Friedman AL, Gustafson DL, Rudnick MS, Lyman H. Biochim Biophys Acta. Phytoplankton populations and their subsequent photosynthetic productivity will fluctuate due to a number of factors, most of which are part of seasonal changes 30. If oxygen levels get too low, fish and other aquatic creatures may die 44. Algae can be found residing in oceans, lakes, rivers, ponds and even in snow, anywhere on Earth. A large increase in the spring normally occurs as light conditions improve and water begins to mix 1. This affects the color of the organism, and certain types of chlorophyll can only be found in algae. Organisms that eat the shellfish (including humans) are consuming the concentrated toxins, which can reach deadly levels 52. [21], Genetic and ultrastructural evidence place the Phaeophyceae among the heterokonts (Stramenopiles),[22] a large assemblage of organisms that includes both photosynthetic members with plastids (such as the diatoms) as well as non-photosynthetic groups (such as the slime nets and water molds). As they are able to produce their own energy with the help of light, they are considered autotrophic (self-feeding). Brown algae belong to the group Heterokontophyta, a large group of eukaryotic organisms distinguished most prominently by having chloroplasts surrounded by four membranes, suggesting an origin from a symbiotic relationship between a basal eukaryote and another eukaryotic organism. Brown algae include a number of edible seaweeds. These effects can be caused by direct or indirect contact with an algal bloom. This process uses bacteriochlorophyll instead of chlorophyll A 19. A food web is a complex net of organisms and food chains (who-eats-who). In most of these organisms, the ratio of chlorophyll A to chlorophyll B is 3:1 21. They reproduce sexually through zoospore which maybe isogamous or anisogamous. Lastly, and most rarely, is chlorophyll E. Not much is known about this pigment except that it is found in some types of golden algae. FOIA Instead, phytoplankton can be divided into two classes, algae and cyanobacteria 10. The color of the tide depends on the pigments present in the phytoplankton 36. Most brown algae live in marine environments, where they play an important role both as food and as a potential habitat. Phycoerythrin. Marine cyanobacteria have higher levels of phycoerythrin, while freshwater species have dominating amounts of phycocyanin. If phytoplankton concentrations are abnormally high or low for a season, it may indicate other water quality concerns that should be addressed. In species of Fucus, the pneumatocysts develop within the lamina itself, either as discrete spherical bladders or as elongated gas-filled regions that take the outline of the lamina in which they develop. chlorophyll, any member of the most important class of pigments involved in photosynthesis, the process by which light energy is converted to chemical energy through the synthesis of organic compounds. Phaeophyta are greenish-brown colored algae that contain fucoxanthin, beta-carotene and chlorophyll a and c. They are the most complex forms of algae, commonly adapted in the marine environment. For all phytoplankton, photosynthetic production will increase with the temperature, though each organism has a slightly different optimum temperature range 1. 2023 Fondriest Environmental, Inc. | Questions? The cookie is used to store the user consent for the cookies in the category "Analytics". .mw-parser-output table.clade{border-spacing:0;margin:0;font-size:100%;line-height:100%;border-collapse:separate;width:auto}.mw-parser-output table.clade table.clade{width:100%;line-height:inherit}.mw-parser-output table.clade td.clade-label{min-width:0.2em;width:0.1em;padding:0 0.15em;vertical-align:bottom;text-align:center;border-left:1px solid;border-bottom:1px solid;white-space:nowrap}.mw-parser-output table.clade td.clade-label::before,.mw-parser-output table.clade td.clade-slabel::before{content:"\2060 "}.mw-parser-output table.clade td.clade-fixed-width{overflow:hidden;text-overflow:ellipsis}.mw-parser-output table.clade td.clade-fixed-width:hover{overflow:visible}.mw-parser-output table.clade td.clade-label.first{border-left:none;border-right:none}.mw-parser-output table.clade td.clade-label.reverse{border-left:none;border-right:1px solid}.mw-parser-output table.clade td.clade-slabel{padding:0 0.15em;vertical-align:top;text-align:center;border-left:1px solid;white-space:nowrap}.mw-parser-output table.clade td.clade-slabel:hover{overflow:visible}.mw-parser-output table.clade td.clade-slabel.last{border-left:none;border-right:none}.mw-parser-output table.clade td.clade-slabel.reverse{border-left:none;border-right:1px solid}.mw-parser-output table.clade td.clade-bar{vertical-align:middle;text-align:left;padding:0 0.5em;position:relative}.mw-parser-output table.clade td.clade-bar.reverse{text-align:right;position:relative}.mw-parser-output table.clade td.clade-leaf{border:0;padding:0;text-align:left}.mw-parser-output table.clade td.clade-leafR{border:0;padding:0;text-align:right}.mw-parser-output table.clade td.clade-leaf.reverse{text-align:right}.mw-parser-output table.clade:hover span.linkA{background-color:yellow}.mw-parser-output table.clade:hover span.linkB{background-color:green}, This is a list of the orders in the class Phaeophyceae:[46][47]. In coastal and open-ocean environments, oceanic circulation is responsible for phytoplankton concentrations. Chlorophyll pigments and other pigments found in brown algae play an important role in the photosynthesis process. [40] A number of Devonian fossils termed fucoids, from their resemblance in outline to species in the genus Fucus, have proven to be inorganic rather than true fossils. Algae. Extraction of Pigments from Brown Algae Functional cookies help to perform certain functionalities like sharing the content of the website on social media platforms, collect feedbacks, and other third-party features. While red tides specifically refer to harmful algal blooms (HABs), they are often simply associated with the discoloration due to a large concentration of phytoplankton 53,43. [11], The simplest browns are filamentousthat is, their cells are elongate and have septa cutting across their width. Photosynth Res. Certain species of these phytoplankton can contain harmful toxins that can affect humans and other animals. A single bloom will only last one to two weeks, as the phytoplankton population will die without the proper oxygen and nutrient levels. [58] Additionally, they can store a great amount of carbon dioxide which can help us in the fight against climate change. Saltwater phytoplankton can be found all over the world, living in the photic (sunlit zone) of the ocean. If too many nutrients are available, it can trigger an algal bloom 12. Insights into the evolution of extracellular matrix polysaccharides in Eukaryotes", "Chemical and enzymatic fractionation of cell walls from Fucales: Insights into the structure of the extracellular matrix of brown algae", "The new higher level classification of eukaryotes with emphasis on the taxonomy of protists", "The eukaryotic tree of life: Endosymbiosis takes its TOL", "Origin and evolution of organisms as deduced from 5S ribosomal RNS sequences", "Transitions between marine and freshwater environments provide new clues about the origins of multicellular plants and algae", "Brown Algae Carbohydrates: Structures, Pharmaceutical Properties, and Research Challenges", University of California Museum of Paleontology, https://en.wikipedia.org/w/index.php?title=Brown_algae&oldid=1136261539, Articles with dead external links from November 2018, Articles with permanently dead external links, Short description is different from Wikidata, Creative Commons Attribution-ShareAlike License 3.0, This page was last edited on 29 January 2023, at 14:23. The difference between these seaweeds and submerged plants is in their structure. Like a root system in plants, a holdfast serves to anchor the alga in place on the substrate where it grows, and thus prevents the alga from being carried away by the current. Whether you need help solving quadratic equations, inspiration for the upcoming science fair or the latest update on a major storm, Sciencing is here to help. The cookie is set by the GDPR Cookie Consent plugin and is used to store whether or not user has consented to the use of cookies. This does not mean that brown algae completely lack specialized structures. [48] Between generations, the algae go through separate sporophyte (diploid) and gametophyte (haploid) phases. These accessory pigments are responsible for other organism colors, such as yellow, red, blue and brown. There are around 1500 species of brown algae, which vary greatly in their size and shape. To be considered a phytoplankton, the algae needs to use chlorophyll A in photosynthesis, be single-celled or colonial (a group of single-cells), and live and die floating in the water, not attached to any substrate 1. It's within these organelles that sunlight, water and carbon dioxide can be used to create energy in the form of glucose (plus oxygen as a by-product). Only the visible light range (blue to red) is considered photosynthetically active radiation 1. Phytoplankton require sunlight for photosynthesis. Green algae: -colored green - chloroplasts -plant ancestors Two main groups: chlorophyta and charophyta. Algae are aquatic, plant-like organisms. Chlorophyll B Chlorophyll B is also a green pigment, and it's found in plants and green algae. Each of these accessory pigments will strongly absorb different wavelengths, so their presence makes photosynthesis more efficient 20. Chls c differ from Chls a, b and d in being Mg-phytoporphyrins rather than Mg-chlorins. Chlorophyll B absorbs blue-violet wavelength light. Marine phytoplankton are mainly comprised of microalgae known as dinoflagellates and diatoms, though other algae and cyanobacteria can be present. An official website of the United States government. The relative carotenoid contents in red marine algae were generally lower than those of chlorophylls. Blades are also often the parts of the alga that bear the reproductive structures. If your institution is not listed or you cannot sign in to your institutions website, please contact your librarian or administrator. The sporophyte stage is often the more visible of the two, though some species of brown algae have similar diploid and haploid phases. Chlorophyll d Chloroblasts of brown algae contain, in addition to chlorophyll, the pigment fucoxanthin, resulting in a brown or olive-green color. [43] Each hollow blade bears up to eight pneumatocysts at its base, and the stipes appear to have been hollow and inflated as well. Select your institution from the list provided, which will take you to your institution's website to sign in. 2 Does brown algae have chlorophyll a and c? Yes, red algae and brown algae have chlorophyll. Phycoerythrin sensors use a wavelength around 540 nm, while phycocyanin sensors emit a wavelength at 600 nm 50. An algal bloom is a sudden increase in the concentration of phytoplankton. In general, chlorophyll a and chlorophyll b were chiefly present in green . Biochim Biophys Acta. The first type is chromista. Filamentous algae are often referred to as pond scum, and appear in eutrophic (nutrient-rich) bodies of water. These blades may be attached directly to the stipe, to a holdfast with no stipe present, or there may be an air bladder between the stipe and blade. "Molecular evolution of 5S ribosomal RNA from red and brown algae", Australian Journal of Marine and Freshwater Research, "A key to the genera of the British seaweeds", "Plant Proteus: brown algal morphological plasticity and underlying developmental mechanisms", "Gazing at Cell Wall Expansion under a Golden Light", "The cell wall polysaccharide metabolism of the brown alga Ectocarpus siliculosus. With less light available, photosynthetic production will decrease. Any one of certain large, tough, brown seaweeds; the source of potassium, iodine, algin, and sodium carbonate. Expected levels should be based on local, seasonal data from previous years. The rockweed shown at left, Fucus distichous, visible at low tide at the Berkeley Marina in California, is somewhat smaller. Fondriest Environmental, Inc. Algae, Phytoplankton and Chlorophyll. Fundamentals of Environmental Measurements. [33] Most fossils of soft-tissue algae preserve only a flattened outline, without the microscopic features that permit the major groups of multicellular algae to be reliably distinguished. [15] Specifically, the brown algal cell wall consists of several components with alginates and sulphated fucan being its main ingredients, up to 40% each of them. Higher plants and green algae contain chlorophyll a and chlorophyll b. Photosynthetic production peaks during the day and declines after dark 24. For librarians and administrators, your personal account also provides access to institutional account management. Large group of multicellular algae, comprising the class Phaeophyceae. The .gov means its official. Macroalgae are simpler, and attach themselves to the seabed with a holdfast instead of true roots 4. 4 Do red and brown algae contain chlorophyll? They are mostly found in marine environments. Phascolophyllaphycus possesses numerous elongate, inflated blades attached to a stipe. Careers. However, most scientists assume that the Phaeophyceae evolved from unicellular ancestors. In turbid water, photosynthesis is more likely to occur at the waters surface than on the lakebed, as more light is available. In many coastal regions, southerly winds cause this coastal upwelling in late summer and autumn 36. Need even more definitions? Ultraviolet light has too much energy for photosynthesis, and infrared light does not have enough. The extent and location of upwells are based on wind patterns, which cause currents across the globe 11. The chlorophyll reflects these wavelengths, so many plants appear green. [53], The photosynthetic system of brown algae is made of a P700 complex containing chlorophyll a. To further complicate this nomenclature, single-celled algae often fall under the broad category of phytoplankton. Phytoplankton consume a similar amount of carbon dioxide as all land plants combined 11. Phytoplankton, both algae and cyanobacteria, can be found in fresh or saltwater 13. For example, the most common types of chlorophyll appear as green. Chlorophyll D is a minor pigment found in some red algae, while the rare Chlorophyll E has been found in yellow-green algae. In the most structurally differentiated brown algae (such as Fucus), the tissues within the stipe are divided into three distinct layers or regions. Brown algae and their unicellular relatives (e.g. In some cases, the bloom cannot be seen by the human eye, though it is still releasing toxins 43. Within the visible light spectrum, chlorophyll strongly absorbs red and blue light while reflecting green light 48. Unable to load your collection due to an error, Unable to load your delegates due to an error. Accessibility Chlorophyll makes plants and algae appear green because it reflects the green wavelengths found in sunlight, while absorbing all other colors. In others (such as Nereocystis), the center of the stipe is hollow and filled with gas that serves to keep that part of the alga buoyant. Don't already have a personal account? Other groups of brown algae grow to much larger sizes. In the image on the right, a piece of an Ulva thallus is being viewed through a microscope. This means that it likely functions in a similar way to chlorophyll B to expand the amount of wavelengths of light that can be absorbed for photosynthesis. Chlorophyll sensors are also an in-situ method for determining the trophic state (nutrient-rich, stable, or nutrient-poor) of an aquatic system 47. The chemical composition and the absorption rate differ in each sub-type. These cookies help provide information on metrics the number of visitors, bounce rate, traffic source, etc. Does brown algae have chlorophyll a and c? A stipe is a stalk or stemlike structure present in an alga. This complex represents about 10--20% of the total chlorophyll in all species; the Acrocarpia paniculata complex has a chlorophyll/P700 ratio of 38. Aquatic plants, whether floating, submerged, or emergent (starting in the water and growing out) have specialized parts such as roots, stems and leaves 3. They range from simple branched, filamentous forms (Ectocarpus) to profusely branched forms as represented by kelps, which may reach a height of 100 meters. Oxygen depletion has two algal-bloom-related causes: respiration and decomposition. The site is secure. [33] Fossils of Drydenia consist of an elliptical blade attached to a branching filamentous holdfast, not unlike some species of Laminaria, Porphyra, or Gigartina. By contrast, diatoms, dinoflagellates, and brown algae do not contain chlorophyll b but do contain, in addition to chloro- phyll a, a characteristic green pigment,chlorophyll c (I, 2). This is what gives many plants their green color and is what allows plants and algae to absorb light for photosynthesis. It's thought that this chlorophyll evolved to suit algae and photosynthetic organisms that live in deep water where not much other light can penetrate. During the photosynthetic process, phytoplankton produce oxygen as a byproduct. KlYOSHI SUGAHARA, NORIO MURATA, ATUSI TAKAMIYA, Fluorescence of chlorophyll in brown algae and diatoms, Plant and Cell Physiology, Volume 12, Issue 3, June 1971, Pages 377385, https://doi.org/10.1093/oxfordjournals.pcp.a074631, At 196C, brown algae and a diatom showed two emission bands of fluorescence at 690695 nm and 705715 nm. Brown algae (brown algae): called "seaweeds", multicellular, mostly living in the sea Red algae get a red color from a pigment called phycoerythrin, which covers the green color of chlorophyll. This means that they are single-celled, prokaryotic (simple) organisms. These accumulations can vary from a small, woolly patch near shore to a widespread, slimy green covering. and transmitted securely. [34] Other algal groups, such as the red algae and green algae, have a number of calcareous members. Brown algae, Red algae, Diatoms, Dinoflagellates, and Euglenoids. Meiosis takes place within several unilocular sporangium along the algae's blade, each one forming either haploid male or female zoospores. As oxygen is required for fish and other aquatic organisms, a decrease in photosynthesis productivity is detrimental to aquatic populations. Cyanobacteria are oxygenic photosynthetic bacteria. Biochim Biophys Acta. The largest influence on phytoplankton levels is nutrient scarcity 13. The overall physical appearance of the holdfast differs among various brown algae and among various substrates. Red algae on the other hand have chlorophyll a and d. They also have the pigments r-phycoerythrin(a large amount which gives them their color) and r-phycocyanin. But, because some botanists define "true" stems, leaves, and roots by the presence of these tissues, their absence in the brown algae means that the stem-like and leaf-like structures found in some groups of brown algae must be described using different terminology. Before plants, algae and phytoplankton used water for photosynthesis, bacteria used H2S and other organic compounds to fix CO2 31. Though microscopic, early cyanobacteria have made a permanent impact on the Earths environment. In temperate and subpolar waters, the seasonal fluctuations are normally fairly large. However, the extent to which temperature affects photosynthesis in algae and cyanobacteria is dependent on the species. We also use third-party cookies that help us analyze and understand how you use this website. Plankton nets do not always catch the smallest of phytoplankton, and do not provide an accurate estimate of water volume 40. Certain species are also used as fertilizer, and several are eaten as a vegetable (e.g., Laminaria) in East Asia and elsewhere. These zoospores form in plurilocular sporangium, and can mature into the sporophyte phase immediately. An increase in the nutrient concentration of a body of water is called eutrophication 13. As upwelling brings nutrient-rich water up to the surface, phytoplankton blooms often appear at this time. To do this, cyanobacteria use the pigment chlorophyll a. The https:// ensures that you are connecting to the The brown algae include the largest and fastest growing of seaweeds. Chlorophyll c is a form of chlorophyll found in certain marine algae, including the photosynthetic Chromista (e.g. A few species (of Padina) calcify with aragonite needles. Chloroblasts that contain chlorophylls a and b give green algae their bright green color. In both fresh and saltwater, a lengthy decrease in phytoplanktonic productivity can lead to a fish kill (massive fish die-off) 1. brown algae, (class Phaeophyceae), class of about 1,500 species of algae in the division Chromophyta, common in cold waters along continental coasts. Kelp. While changes within the same calendar year are normal, populations should stay consistent with previous seasonal fluctuations from year to year. Without phytoplankton, the oxygen supply of the ocean would be cut in half. This is the only pigment directly involved in photosynthesis, but other pigments called . This authentication occurs automatically, and it is not possible to sign out of an IP authenticated account. Enter your library card number to sign in. Red algae, however, contain a variety of pigments, including chlorophyll, red phycoerythrin, blue phycocyanin, carotenes, lutein, and zeaxanthin. Like a dominant trait, the more intense, reflected green wavelengths can mask the other, less-reflected colors 20. Species of Sargassum also bear many blades and pneumatocysts, but both kinds of structures are attached separately to the stipe by short stalks. To survive, every living thing needs organic carbon 29. [41] Likewise, the fossil Protosalvinia was once considered a possible brown alga, but is now thought to be an early land plant. Cyanobacteria and other phytoplankton photosynthesize as plants do, and produce the same sugar and oxygen for use in cellular respiration. Oceanic circulation and upwelling ensures that the coastal environments have the highest rates of primary production in the ocean 13. These algal blooms can grow large enough to be seen from a satellite, covering hundreds of square kilometers 11. These types have a habitat on rocky coasts in temperate zones or open seas . Photosynthesis is the process by which organisms use sunlight to produce sugars for energy. In most of these organisms, the ratio of chlorophyll A to chlorophyll B is 3:1 21. 8600 Rockville Pike Freshwater species are rare. These harmful algal blooms can also cause shellfish poisoning in humans and other adverse effects 13. These estimates are then used to develop parameter limits for bodies of water. These cookies will be stored in your browser only with your consent. Red algae possess chlorophyll a and lipid-based pigments called phycobilins, which give them the brilliant red(or deep blue) color. [39] Because these fossils lack features diagnostic for identification at even the highest level, they are assigned to fossil form taxa according to their shape and other gross morphological features. This cookie is set by GDPR Cookie Consent plugin. They are single cellular organisms. The single known specimen of Hungerfordia branches dichotomously into lobes and resembles genera like Chondrus and Fucus[33] or Dictyota. It may be a single or a divided structure, and may be spread over a substantial portion of the alga. In addition to Chls c 1, c 2 and c 3, many new Chl c-like pigments have recently been isolated and . The term single-celled plants is a misnomer, and should not be used. Importance of Algae. Omissions? As such, algal taxonomy is still under debate, with some organizations classifying algae under different kingdoms, including Plantae, Protozoa and Chromista 4,6,8,9. (a) Brown algae contain chlorophyll a, chlorophyll c, -and -carbotenes, xanthophylls and fucoxanthin pigments in the chromatophores. Even during non-toxic algal blooms, the aquatic environment can be compromised. Search for other works by this author on: Department of Biophysics and Biochemistry, Faculty of Science, University of Tokyo. However, a few groups (such as Ectocarpus) grow by a diffuse, unlocalized production of new cells that can occur anywhere on the thallus. Blue-green algae, or cyanobacteria, are the only phytoplankton that contain phycocyanin and phycoerythrin, making the pigments good indicators of the amount of cyanobacteria in a body of water 15. Two main light-harvesting complexes have also been isolated, which have properties unique to brown algae. Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree. To purchase short-term access, please sign in to your personal account above. Turbidity, or the presence of suspended particles in the water, affects the amount of light that reaches into the water 1. Photosynthetic acclimation: structural reorganisation of light harvesting antenna--role of redox-dependent phosphorylation of major and minor chlorophyll a/b binding proteins. Pigments appear as a certain color since they only absorb certain wavelengths of light and reflect the light (and thus the color) that they do not absorb. Early cyanobacteria were the first organism to use water to fix carbon 31. [42], A number of Paleozoic fossils have been tentatively classified with the brown algae, although most have also been compared to known red algae species. Algal blooms come in many colors from green to red, brown, blue, white or purple 43. 22 Oct. 2014. Direct exposure can occur from swimming or drinking affected water. This is supported by the fact that it isn't found in all photosynthetic organisms. By clicking Accept All, you consent to the use of ALL the cookies. The smallest members of the group grow as tiny, feathery tufts of threadlike cells no more than a few centimeters (a few inches) long. It has a blue-green color and is an accessory pigment, particularly significant in its absorption of light in the 44752 nm wavelength region.