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116-538: Phytoplankton ( / ˌ f aɪ t oʊ ˈ p l æ ŋ k t ə n / ) are the autotrophic (self-feeding) components of the plankton community and a key part of ocean and freshwater ecosystems . The name comes from the Greek words φυτόν ( phyton ), meaning ' plant ', and πλαγκτός ( planktos ), meaning 'wanderer' or 'drifter'. Phytoplankton obtain their energy through photosynthesis , as trees and other plants do on land. This means phytoplankton must have light from

232-401: A cyst . Different types of dinoflagellate cysts are mainly defined based on morphological (number and type of layers in the cell wall) and functional (long- or short-term endurance) differences. These characteristics were initially thought to clearly distinguish pellicle (thin-walled) cysts from resting (double-walled) dinoflagellate cysts. The former were considered short-term (temporal) and

348-477: A haplontic life cycle , with the possible exception of Noctiluca and its relatives. The life cycle usually involves asexual reproduction by means of mitosis, either through desmoschisis or eleuteroschisis . More complex life cycles occur, more particularly with parasitic dinoflagellates. Sexual reproduction also occurs, though this mode of reproduction is only known in a small percentage of dinoflagellates. This takes place by fusion of two individuals to form

464-555: A monophyletic group of single-celled eukaryotes constituting the phylum Dinoflagellata and are usually considered protists . Dinoflagellates are mostly marine plankton , but they are also common in freshwater habitats . Their populations vary with sea surface temperature , salinity , and depth. Many dinoflagellates are photosynthetic , but a large fraction of these are in fact mixotrophic , combining photosynthesis with ingestion of prey ( phagotrophy and myzocytosis ). In terms of number of species, dinoflagellates are one of

580-560: A zygote , which may remain mobile in typical dinoflagellate fashion and is then called a planozygote. This zygote may later form a resting stage or hypnozygote , which is called a dinoflagellate cyst or dinocyst . After (or before) germination of the cyst, the hatchling undergoes meiosis to produce new haploid cells . Dinoflagellates appear to be capable of carrying out several DNA repair processes that can deal with different types of DNA damage . The life cycle of many dinoflagellates includes at least one nonflagellated benthic stage as

696-506: A better view of their global distribution. The term phytoplankton encompasses all photoautotrophic microorganisms in aquatic food webs . However, unlike terrestrial communities , where most autotrophs are plants , phytoplankton are a diverse group, incorporating protistan eukaryotes and both eubacterial and archaebacterial prokaryotes . There are about 5,000 known species of marine phytoplankton. How such diversity evolved despite scarce resources (restricting niche differentiation )

812-434: A body of water or cultured, though the former method is seldom used. Phytoplankton is used as a foodstock for the production of rotifers , which are in turn used to feed other organisms. Phytoplankton is also used to feed many varieties of aquacultured molluscs , including pearl oysters and giant clams . A 2018 study estimated the nutritional value of natural phytoplankton in terms of carbohydrate, protein and lipid across

928-580: A calcium carbonate shell called a coccosphere that is sensitive to ocean acidification. Because of their short generation times, evidence suggests some phytoplankton can adapt to changes in pH induced by increased carbon dioxide on rapid time-scales (months to years). Phytoplankton serve as the base of the aquatic food web, providing an essential ecological function for all aquatic life. Under future conditions of anthropogenic warming and ocean acidification, changes in phytoplankton mortality due to changes in rates of zooplankton grazing may be significant. One of

1044-525: A culture medium. This water must be sterilized , usually by either high temperatures in an autoclave or by exposure to ultraviolet radiation , to prevent biological contamination of the culture. Various fertilizers are added to the culture medium to facilitate the growth of plankton. A culture must be aerated or agitated in some way to keep plankton suspended, as well as to provide dissolved carbon dioxide for photosynthesis . In addition to constant aeration, most cultures are manually mixed or stirred on

1160-401: A dinokaryon are classified under Syndiniales . Although classified as eukaryotes , the dinoflagellate nuclei are not characteristically eukaryotic, as some of them lack histones and nucleosomes , and maintain continually condensed chromosomes during mitosis . The dinoflagellate nucleus was termed 'mesokaryotic' by Dodge (1966), due to its possession of intermediate characteristics between

1276-773: A fundamental principle to understand marine ecology, biogeochemistry and phytoplankton evolution. However, the Redfield ratio is not a universal value and it may diverge due to the changes in exogenous nutrient delivery and microbial metabolisms in the ocean, such as nitrogen fixation , denitrification and anammox . The dynamic stoichiometry shown in unicellular algae reflects their capability to store nutrients in an internal pool, shift between enzymes with various nutrient requirements and alter osmolyte composition. Different cellular components have their own unique stoichiometry characteristics, for instance, resource (light or nutrients) acquisition machinery such as proteins and chlorophyll contain

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1392-494: A high concentration of nitrogen but low in phosphorus. Meanwhile, growth machinery such as ribosomal RNA contains high nitrogen and phosphorus concentrations. Based on allocation of resources, phytoplankton is classified into three different growth strategies, namely survivalist, bloomer and generalist. Survivalist phytoplankton has a high ratio of N:P (>30) and contains an abundance of resource-acquisition machinery to sustain growth under scarce resources. Bloomer phytoplankton has

1508-401: A lack of diversity may occur in a bloom is through a reduction in predation and a decreased competition. The first may be achieved by having predators reject the dinoflagellate, by, for example, decreasing the amount of food it can eat. This additionally helps prevent a future increase in predation pressure by causing predators that reject it to lack the energy to breed. A species can then inhibit

1624-565: A low N:P ratio (<10), contains a high proportion of growth machinery, and is adapted to exponential growth. Generalist phytoplankton has similar N:P to the Redfield ratio and contain relatively equal resource-acquisition and growth machinery. The NAAMES study was a five-year scientific research program conducted between 2015 and 2019 by scientists from Oregon State University and NASA to investigated aspects of phytoplankton dynamics in ocean ecosystems, and how such dynamics influence atmospheric aerosols , clouds, and climate (NAAMES stands for

1740-458: A novel, dominant family of nuclear proteins that appear to be of viral origin, thus are called Dinoflagellate viral nucleoproteins (DVNPs) which are highly basic, bind DNA with similar affinity to histones, and occur in multiple posttranslationally modified forms. Dinoflagellate nuclei remain condensed throughout interphase rather than just during mitosis , which is closed and involves a uniquely extranuclear mitotic spindle . This sort of nucleus

1856-434: A nutritional supplement for captive invertebrates in aquaria . Culture sizes range from small-scale laboratory cultures of less than 1L to several tens of thousands of litres for commercial aquaculture. Regardless of the size of the culture, certain conditions must be provided for efficient growth of plankton. The majority of cultured plankton is marine, and seawater of a specific gravity of 1.010 to 1.026 may be used as

1972-510: A plastid derived from secondary endosymbiosis of red algae, however dinoflagellates with plastids derived from green algae and tertiary endosymbiosis of diatoms have also been discovered. Similar to other photosynthetic organisms, dinoflagellates contain chlorophylls a and c2 and the carotenoid beta-carotene. Dinoflagellates also produce the xanthophylls including peridinin , dinoxanthin , and diadinoxanthin . These pigments give many dinoflagellates their typical golden brown color. However,

2088-622: A portion of the ATP produced during photosynthesis or the oxidation of chemical compounds to reduce NADP to NADPH to form organic compounds. The term autotroph was coined by the German botanist Albert Bernhard Frank in 1892. It stems from the ancient Greek word τροφή ( trophḗ ), meaning "nourishment" or "food". The first autotrophic organisms likely evolved early in the Archean but proliferated across Earth's Great Oxidation Event with an increase to

2204-567: A potent neurotoxin that immobilizes its prey upon contact. When K. arminger are present in large enough quantities, they are able to cull whole populations of its copepods prey. The feeding mechanisms of the oceanic dinoflagellates remain unknown, although pseudopodial extensions were observed in Podolampas bipes . Dinoflagellate blooms are generally unpredictable, short, with low species diversity, and with little species succession. The low species diversity can be due to multiple factors. One way

2320-560: A reactor of the Chernobyl nuclear power plant . There are many different types of autotrophs in Earth's ecosystems. Lichens located in tundra climates are an exceptional example of a primary producer that, by mutualistic symbiosis, combines photosynthesis by algae (or additionally nitrogen fixation by cyanobacteria) with the protection of a decomposer fungus . As there are many examples of primary producers, two dominant types are coral and one of

2436-490: A regular basis. Light must be provided for the growth of phytoplankton. The colour temperature of illumination should be approximately 6,500 K, but values from 4,000 K to upwards of 20,000 K have been used successfully. The duration of light exposure should be approximately 16 hours daily; this is the most efficient artificial day length. Marine phytoplankton perform half of the global photosynthetic CO 2 fixation (net global primary production of ~50 Pg C per year) and half of

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2552-852: A result of the abundant nutrients in the water. Although the resulting red waves are an interesting visual phenomenon, they contain toxins that not only affect all marine life in the ocean, but the people who consume them as well. A specific carrier is shellfish . This can introduce both nonfatal and fatal illnesses. One such poison is saxitoxin , a powerful paralytic neurotoxin . Human inputs of phosphate further encourage these red tides, so strong interest exists in learning more about dinoflagellates, from both medical and economic perspectives. Dinoflagellates are known to be particularly capable of scavenging dissolved organic phosphorus for P-nutrient, several HAS species have been found to be highly versatile and mechanistically diversified in utilizing different types of DOPs. The ecology of harmful algal blooms

2668-542: A source of carbon , but are able to use light or inorganic compounds as a source of energy. Such organisms are mixotrophs . An organism that obtains carbon from organic compounds but obtains energy from light is called a photoheterotroph , while an organism that obtains carbon from organic compounds and energy from the oxidation of inorganic compounds is termed a chemolithoheterotroph . Evidence suggests that some fungi may also obtain energy from ionizing radiation : Such radiotrophic fungi were found growing inside

2784-493: A species increases rapidly under conditions favorable to growth can produce harmful algal blooms (HABs). Phytoplankton are a key food item in both aquaculture and mariculture . Both utilize phytoplankton as food for the animals being farmed. In mariculture, the phytoplankton is naturally occurring and is introduced into enclosures with the normal circulation of seawater. In aquaculture, phytoplankton must be obtained and introduced directly. The plankton can either be collected from

2900-531: A total of 2,294 living dinoflagellate species, which includes marine, freshwater, and parasitic dinoflagellates. A rapid accumulation of certain dinoflagellates can result in a visible coloration of the water, colloquially known as red tide (a harmful algal bloom ), which can cause shellfish poisoning if humans eat contaminated shellfish. Some dinoflagellates also exhibit bioluminescence , primarily emitting blue-green light, which may be visible in oceanic areas under certain conditions. The term "dinoflagellate"

3016-411: A turning force. The longitudinal flagellum is relatively conventional in appearance, with few or no hairs. It beats with only one or two periods to its wave. The flagella lie in surface grooves: the transverse one in the cingulum and the longitudinal one in the sulcus, although its distal portion projects freely behind the cell. In dinoflagellate species with desmokont flagellation (e.g., Prorocentrum ),

3132-649: Is a combination of the Greek dinos and the Latin flagellum . Dinos means "whirling" and signifies the distinctive way in which dinoflagellates were observed to swim. Flagellum means "whip" and this refers to their flagella . In 1753, the first modern dinoflagellates were described by Henry Baker as "Animalcules which cause the Sparkling Light in Sea Water", and named by Otto Friedrich Müller in 1773. The term derives from

3248-463: Is a notable exception). While almost all phytoplankton species are obligate photoautotrophs , there are some that are mixotrophic and other, non-pigmented species that are actually heterotrophic (the latter are often viewed as zooplankton ). Of these, the best known are dinoflagellate genera such as Noctiluca and Dinophysis , that obtain organic carbon by ingesting other organisms or detrital material. Phytoplankton live in

3364-448: Is called a red tide , from the color the bloom imparts to the water. Some colorless dinoflagellates may also form toxic blooms, such as Pfiesteria . Some dinoflagellate blooms are not dangerous. Bluish flickers visible in ocean water at night often come from blooms of bioluminescent dinoflagellates, which emit short flashes of light when disturbed. A red tide occurs because dinoflagellates are able to reproduce rapidly and copiously as

3480-496: Is declining, leading to higher light penetration and potentially more primary production; however, there are conflicting predictions for the effects of variable mixing patterns and changes in nutrient supply and for productivity trends in polar zones. The effect of human-caused climate change on phytoplankton biodiversity is not well understood. Should greenhouse gas emissions continue rising to high levels by 2100, some phytoplankton models predict an increase in species richness , or

3596-489: Is driven by — the Redfield ratio of macronutrients generally available throughout the surface oceans. Phytoplankton also rely on trace metals such as iron (Fe), manganese (Mn), zinc (Zn), cobalt (Co), cadmium (Cd) and copper (Cu) as essential micronutrients, influencing their growth and community composition. Limitations in these metals can lead to co-limitations and shifts in phytoplankton community structure. Across large areas of

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3712-876: Is evaluating the contributions of phytoplankton to carbon fixation and forecasting how this production may change in response to perturbations. Predicting the effects of climate change on primary productivity is complicated by phytoplankton bloom cycles that are affected by both bottom-up control (for example, availability of essential nutrients and vertical mixing) and top-down control (for example, grazing and viruses). Increases in solar radiation, temperature and freshwater inputs to surface waters strengthen ocean stratification and consequently reduce transport of nutrients from deep water to surface waters, which reduces primary productivity. Conversely, rising CO 2 levels can increase phytoplankton primary production, but only when nutrients are not limiting. Some studies indicate that overall global oceanic phytoplankton density has decreased in

3828-412: Is extensively studied. At night, water can have an appearance of sparkling light due to the bioluminescence of dinoflagellates. More than 18 genera of dinoflagellates are bioluminescent, and the majority of them emit a blue-green light. These species contain scintillons , individual cytoplasmic bodies (about 0.5 μm in diameter) distributed mainly in the cortical region of the cell, outpockets of

3944-422: Is of utmost importance to secondary producers such as copepods, fish and shrimp, because it determines the nutritional quality and influences energy flow through the marine food chains . Climate change may greatly restructure phytoplankton communities leading to cascading consequences for marine food webs , thereby altering the amount of carbon transported to the ocean interior. The figure gives an overview of

4060-427: Is pH sensitive. When the pH drops, luciferase changes its shape, allowing luciferin, more specifically tetrapyrrole, to bind. Dinoflagellates can use bioluminescence as a defense mechanism. They can startle their predators by their flashing light or they can ward off potential predators by an indirect effect such as the "burglar alarm". The bioluminescence attracts attention to the dinoflagellate and its attacker, making

4176-445: Is predicted to co-occur with ocean acidification and warming, due to increased stratification of the water column and reduced mixing of nutrients from the deep water to the surface. The compartments influenced by phytoplankton include the atmospheric gas composition, inorganic nutrients, and trace element fluxes as well as the transfer and cycling of organic matter via biological processes (see figure). The photosynthetically fixed carbon

4292-450: Is rapidly recycled and reused in the surface ocean, while a certain fraction of this biomass is exported as sinking particles to the deep ocean, where it is subject to ongoing transformation processes, e.g., remineralization. Phytoplankton contribute to not only a basic pelagic marine food web but also to the microbial loop. Phytoplankton are the base of the marine food web and because they do not rely on other organisms for food, they make up

4408-793: Is sufficient for nutrition, are classified as amphitrophic. If both forms are required, the organisms are mixotrophic sensu stricto . Some free-living dinoflagellates do not have chloroplasts, but host a phototrophic endosymbiont. A few dinoflagellates may use alien chloroplasts (cleptochloroplasts), obtained from food ( kleptoplasty ). Some dinoflagellates may feed on other organisms as predators or parasites. Food inclusions contain bacteria, bluegreen algae, diatoms, ciliates, and other dinoflagellates. Mechanisms of capture and ingestion in dinoflagellates are quite diverse. Several dinoflagellates, both thecate (e.g. Ceratium hirundinella , Peridinium globulus ) and nonthecate (e.g. Oxyrrhis marina , Gymnodinium sp. and Kofoidinium spp. ), draw prey to

4524-600: Is supported by phylogenetic evidence – the physiology and habitat of the last universal common ancestor (LUCA) is inferred to have also been a thermophilic anaerobe with a Wood-Ljungdahl pathway, its biochemistry was replete with FeS clusters and radical reaction mechanisms. It was dependent upon Fe, H 2 , and CO 2 . The high concentration of K present within the cytosol of most life forms suggests that early cellular life had Na /H antiporters or possibly symporters. Autotrophs possibly evolved into heterotrophs when they were at low H 2 partial pressures where

4640-470: Is unclear. In terms of numbers, the most important groups of phytoplankton include the diatoms , cyanobacteria and dinoflagellates , although many other groups of algae are represented. One group, the coccolithophorids , is responsible (in part) for the release of significant amounts of dimethyl sulfide (DMS) into the atmosphere . DMS is oxidized to form sulfate which, in areas where ambient aerosol particle concentrations are low, can contribute to

4756-496: Is usually accumulated in the form of biomass and will be used as carbon and energy source by other organisms (e.g. heterotrophs and mixotrophs ). The photoautotrophs are the main primary producers, converting the energy of the light into chemical energy through photosynthesis , ultimately building organic molecules from carbon dioxide , an inorganic carbon source . Examples of chemolithotrophs are some archaea and bacteria (unicellular organisms) that produce biomass from

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4872-529: The International Code of Botanical Nomenclature (ICBN, now renamed as ICN) and the International Code of Zoological Nomenclature (ICZN). About half of living dinoflagellate species are autotrophs possessing chloroplasts and half are nonphotosynthesising heterotrophs. The peridinin dinoflagellates, named after their peridinin plastids, appear to be ancestral for the dinoflagellate lineage. Almost half of all known species have chloroplasts, which are either

4988-449: The diatoms ). Most phytoplankton are too small to be individually seen with the unaided eye . However, when present in high enough numbers, some varieties may be noticeable as colored patches on the water surface due to the presence of chlorophyll within their cells and accessory pigments (such as phycobiliproteins or xanthophylls ) in some species. Phytoplankton are photosynthesizing microscopic protists and bacteria that inhabit

5104-419: The diatoms ). Many other organism groups formally named as phytoplankton, including coccolithophores and dinoflagellates , are now no longer included as they are not only phototrophic but can also eat. These organisms are now more correctly termed  mixoplankton . This recognition has important consequences for how we view the functioning of the planktonic food web. Phytoplankton obtain energy through

5220-603: The flagellate order Dinoflagellida. Botanists treated them as a division of algae, named Pyrrophyta or Pyrrhophyta ("fire algae"; Greek pyrr(h)os , fire) after the bioluminescent forms, or Dinophyta . At various times, the cryptomonads , ebriids , and ellobiopsids have been included here, but only the last are now considered close relatives. Dinoflagellates have a known ability to transform from noncyst to cyst-forming strategies, which makes recreating their evolutionary history extremely difficult. Dinoflagellates are unicellular and possess two dissimilar flagella arising from

5336-545: The oxidation of inorganic chemical compounds, these organisms are called chemoautotrophs , and are frequently found in hydrothermal vents in the deep ocean. Primary producers are at the lowest trophic level , and are the reasons why Earth sustains life to this day. Most chemoautotrophs are lithotrophs , using inorganic electron donors such as hydrogen sulfide, hydrogen gas , elemental sulfur , ammonium and ferrous oxide as reducing agents and hydrogen sources for biosynthesis and chemical energy release. Autotrophs use

5452-448: The photic zone of the ocean, where photosynthesis is possible. During photosynthesis, they assimilate carbon dioxide and release oxygen. If solar radiation is too high, phytoplankton may fall victim to photodegradation . Phytoplankton species feature a large variety of photosynthetic pigments which species-specifically enables them to absorb different wavelengths of the variable underwater light. This implies different species can use

5568-430: The process of photosynthesis and must therefore live in the well-lit surface layer (termed the euphotic zone ) of an ocean , sea , lake , or other body of water. Phytoplankton account for about half of all photosynthetic activity on Earth. Their cumulative energy fixation in carbon compounds ( primary production ) is the basis for the vast majority of oceanic and also many freshwater food webs ( chemosynthesis

5684-401: The sun . Plants can only use a fraction (approximately 1%) of this energy for photosynthesis . The process of photosynthesis splits a water molecule (H 2 O), releasing oxygen (O 2 ) into the atmosphere, and reducing carbon dioxide (CO 2 ) to release the hydrogen atoms that fuel the metabolic process of primary production . Plants convert and store the energy of the photons into

5800-455: The theca or lorica , as opposed to athecate ("nude") dinoflagellates. These occur in various shapes and arrangements, depending on the species and sometimes on the stage of the dinoflagellate. Conventionally, the term tabulation has been used to refer to this arrangement of thecal plates . The plate configuration can be denoted with the plate formula or tabulation formula. Fibrous extrusomes are also found in many forms. A transverse groove,

5916-468: The 350 described freshwater species and a little more than 10% of the known marine species. Dinoflagellates are alveolates possessing two flagella , the ancestral condition of bikonts . About 1,555 species of free-living marine dinoflagellates are currently described. Another estimate suggests about 2,000 living species, of which more than 1,700 are marine (free-living, as well as benthic) and about 220 are from fresh water. The latest estimates suggest

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6032-430: The Greek word δῖνος ( dînos ), meaning whirling, and Latin flagellum , a diminutive term for a whip or scourge. In the 1830s, the German microscopist Christian Gottfried Ehrenberg examined many water and plankton samples and proposed several dinoflagellate genera that are still used today including Peridinium, Prorocentrum , and Dinophysis . These same dinoflagellates were first defined by Otto Bütschli in 1885 as

6148-598: The North Atlantic Aerosols and Marine Ecosystems Study). The study focused on the sub-arctic region of the North Atlantic Ocean, which is the site of one of Earth's largest recurring phytoplankton blooms. The long history of research in this location, as well as relative ease of accessibility, made the North Atlantic an ideal location to test prevailing scientific hypotheses in an effort to better understand

6264-528: The United States, Central Florida is home to the Indian River Lagoon which is abundant with dinoflagellates in the summer and bioluminescent ctenophore in the winter. Dinoflagellates produce characteristic lipids and sterols. One of these sterols is typical of dinoflagellates and is called dinosterol . Dinoflagellate theca can sink rapidly to the seafloor in marine snow . Dinoflagellates have

6380-411: The ability of phytoplankton to store carbon that was emitted by human activities. Human (anthropogenic) changes to phytoplankton impact both natural and economic processes. Autotroph The primary producers can convert the energy in the light ( phototroph and photoautotroph ) or the energy in inorganic chemical compounds ( chemotrophs or chemolithotrophs ) to build organic molecules , which

6496-451: The ability of the dinoflagellate to prey upon larger copepods. Toxic strains of K. veneficum produce karlotoxin that kills predators who ingest them, thus reducing predatory populations and allowing blooms of both toxic and non-toxic strains of K. veneficum . Further, the production of karlotoxin enhances the predatory ability of K. veneficum by immobilizing its larger prey. K. arminger are more inclined to prey upon copepods by releasing

6612-455: The advantages of recombination and sexuality, such that in fungi, for example, complex combinations of haploid and diploid cycles have evolved that include asexual and sexual resting stages. However, in the general life cycle of cyst-producing dinoflagellates as outlined in the 1960s and 1970s, resting cysts were assumed to be the fate of sexuality, which itself was regarded as a response to stress or unfavorable conditions. Sexuality involves

6728-404: The base of marine and freshwater food webs and are key players in the global carbon cycle . They account for about half of global photosynthetic activity and at least half of the oxygen production, despite amounting to only about 1% of the global plant biomass. Phytoplankton are very diverse, comprising photosynthesizing bacteria ( cyanobacteria ) and various unicellular protist groups (notably

6844-407: The biological systems of Earth would be unable to sustain themselves. Plants, along with other primary producers, produce the energy that other living beings consume, and the oxygen that they breathe. It is thought that the first organisms on Earth were primary producers located on the ocean floor. Autotrophs are fundamental to the food chains of all ecosystems in the world. They take energy from

6960-480: The chemical bonds of simple sugars during photosynthesis. These plant sugars are polymerized for storage as long-chain carbohydrates , such as starch and cellulose; glucose is also used to make fats and proteins . When autotrophs are eaten by heterotrophs , i.e., consumers such as animals, the carbohydrates , fats , and proteins contained in them become energy sources for the heterotrophs . Proteins can be made using nitrates , sulfates , and phosphates in

7076-562: The coiled DNA areas of prokaryotic bacteria and the well-defined eukaryotic nucleus. This group, however, does contain typically eukaryotic organelles , such as Golgi bodies, mitochondria, and chloroplasts. Jakob Schiller (1931–1937) provided a description of all the species, both marine and freshwater, known at that time. Later, Alain Sournia (1973, 1978, 1982, 1990, 1993) listed the new taxonomic entries published after Schiller (1931–1937). Sournia (1986) gave descriptions and illustrations of

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7192-416: The conclusion that encystment is associated with sexual reproduction. These observations also gave credence to the idea that microalgal encystment is essentially a process whereby zygotes prepare themselves for a dormant period. Because the resting cysts studied until that time came from sexual processes, dormancy was associated with sexuality, a presumption that was maintained for many years. This attribution

7308-480: The cysts remain in the sediment layer during conditions unfavorable for vegetative growth and, from there, reinoculate the water column when favorable conditions are restored. Indeed, during dinoflagellate evolution the need to adapt to fluctuating environments and/or to seasonality is thought to have driven the development of this life cycle stage. Most protists form dormant cysts in order to withstand starvation and UV damage. However, there are enormous differences in

7424-482: The dinoflagellates Karenia brevis , Karenia mikimotoi , and Karlodinium micrum have acquired other pigments through endosymbiosis, including fucoxanthin . This suggests their chloroplasts were incorporated by several endosymbiotic events involving already colored or secondarily colorless forms. The discovery of plastids in the Apicomplexa has led some to suggest they were inherited from an ancestor common to

7540-436: The environment in the form of sunlight or inorganic chemicals and use it to create fuel molecules such as carbohydrates. This mechanism is called primary production . Other organisms, called heterotrophs , take in autotrophs as food to carry out functions necessary for their life. Thus, heterotrophs – all animals , almost all fungi , as well as most bacteria and protozoa – depend on autotrophs, or primary producers , for

7656-432: The first cellular lifeforms were not heterotrophs as they would rely upon autotrophs since organic substrates delivered from space were either too heterogeneous to support microbial growth or too reduced to be fermented. Instead, they consider that the first cells were autotrophs. These autotrophs might have been thermophilic and anaerobic chemolithoautotrophs that lived at deep sea alkaline hydrothermal vents. This view

7772-501: The first form of heterotrophy were likely amino acid and clostridial type purine fermentations. It has been suggested that photosynthesis emerged in the presence of faint near infrared light emitted by hydrothermal vents. The first photochemically active pigments are then thought to be Zn-tetrapyrroles. Dinoflagellate The dinoflagellates (from Ancient Greek δῖνος ( dînos )  'whirling' and Latin flagellum  'whip, scourge') are

7888-497: The first trophic level. Organisms such as zooplankton feed on these phytoplankton which are in turn fed on by other organisms and so forth until the fourth trophic level is reached with apex predators. Approximately 90% of total carbon is lost between trophic levels due to respiration, detritus, and dissolved organic matter. This makes the remineralization process and nutrient cycling performed by phytoplankton and bacteria important in maintaining efficiency. Phytoplankton blooms in which

8004-529: The fusion of haploid gametes from motile planktonic vegetative stages to produce diploid planozygotes that eventually form cysts, or hypnozygotes , whose germination is subject to both endogenous and exogenous controls. Endogenously, a species-specific physiological maturation minimum period (dormancy) is mandatory before germination can occur. Thus, hypnozygotes were also referred to as "resting" or "resistant" cysts, in reference to this physiological trait and their capacity following dormancy to remain viable in

8120-459: The genus Symbiodinium ). The association between Symbiodinium and reef-building corals is widely known. However, endosymbiontic Zooxanthellae inhabit a great number of other invertebrates and protists, for example many sea anemones , jellyfish , nudibranchs , the giant clam Tridacna , and several species of radiolarians and foraminiferans . Many extant dinoflagellates are parasites (here defined as organisms that eat their prey from

8236-511: The global population of phytoplankton is an area of active research. Changes in the vertical stratification of the water column, the rate of temperature-dependent biological reactions, and the atmospheric supply of nutrients are expected to have important effects on future phytoplankton productivity. The effects of anthropogenic ocean acidification on phytoplankton growth and community structure has also received considerable attention. The cells of coccolithophore phytoplankton are typically covered in

8352-401: The growth of its competitors, thus achieving dominance. Dinoflagellates sometimes bloom in concentrations of more than a million cells per millilitre. Under such circumstances, they can produce toxins (generally called dinotoxins ) in quantities capable of killing fish and accumulating in filter feeders such as shellfish , which in turn may be passed on to people who eat them. This phenomenon

8468-721: The inside, i.e. endoparasites , or that remain attached to their prey for longer periods of time, i.e. ectoparasites). They can parasitize animal or protist hosts. Protoodinium, Crepidoodinium, Piscinoodinium , and Blastodinium retain their plastids while feeding on their zooplanktonic or fish hosts. In most parasitic dinoflagellates, the infective stage resembles a typical motile dinoflagellate cell. Three nutritional strategies are seen in dinoflagellates: phototrophy , mixotrophy , and heterotrophy . Phototrophs can be photoautotrophs or auxotrophs . Mixotrophic dinoflagellates are photosynthetically active, but are also heterotrophic. Facultative mixotrophs, in which autotrophy or heterotrophy

8584-435: The key mediators of the biological pump . Understanding the response of phytoplankton to changing environmental conditions is a prerequisite to predict future atmospheric concentrations of CO 2 . Temperature, irradiance and nutrient concentrations, along with CO 2 are the chief environmental factors that influence the physiology and stoichiometry of phytoplankton. The stoichiometry or elemental composition of phytoplankton

8700-485: The largest groups of marine eukaryotes, although substantially smaller than diatoms . Some species are endosymbionts of marine animals and play an important part in the biology of coral reefs . Other dinoflagellates are unpigmented predators on other protozoa, and a few forms are parasitic (for example, Oodinium and Pfiesteria ). Some dinoflagellates produce resting stages, called dinoflagellate cysts or dinocysts , as part of their lifecycles; this occurs in 84 of

8816-432: The latter long-term (resting) cysts. However, during the last two decades further knowledge has highlighted the great intricacy of dinoflagellate life histories. More than 10% of the approximately 2000 known marine dinoflagellate species produce cysts as part of their life cycle (see diagram on the right). These benthic phases play an important role in the ecology of the species, as part of a planktonic-benthic link in which

8932-498: The main cell vacuole. They contain dinoflagellate luciferase , the main enzyme involved in dinoflagellate bioluminescence, and luciferin , a chlorophyll-derived tetrapyrrole ring that acts as the substrate to the light-producing reaction. The luminescence occurs as a brief (0.1 sec) blue flash (max 476 nm) when stimulated, usually by mechanical disturbance. Therefore, when mechanically stimulated—by boat, swimming, or waves, for example—a blue sparkling light can be seen emanating from

9048-405: The main phenotypic, physiological and resistance properties of each dinoflagellate species cysts. Unlike in higher plants most of this variability, for example in dormancy periods, has not been proven yet to be attributed to latitude adaptation or to depend on other life cycle traits. Thus, despite recent advances in the understanding of the life histories of many dinoflagellate species, including

9164-491: The many food chains in the ocean – remarkable due to the small number of links – is that of phytoplankton sustaining krill (a crustacean similar to a tiny shrimp), which in turn sustain baleen whales . The El Niño-Southern Oscillation (ENSO) cycles in the Equatorial Pacific area can affect phytoplankton. Biochemical and physical changes during ENSO cycles modify the phytoplankton community structure. Also, changes in

9280-498: The many types of brown algae, kelp. Gross primary production occurs by photosynthesis. This is the main way that primary producers get energy and make it available to other forms of life. Plants, many corals (by means of intracellular algae), some bacteria ( cyanobacteria ), and algae do this. During photosynthesis, primary producers receive energy from the sun and use it to produce sugar and oxygen. Without primary producers, organisms that are capable of producing energy on their own,

9396-1151: The marine genera of dinoflagellates, excluding information at the species level. The latest index is written by Gómez. English-language taxonomic monographs covering large numbers of species are published for the Gulf of Mexico, the Indian Ocean, the British Isles, the Mediterranean and the North Sea. The main source for identification of freshwater dinoflagellates is the Süsswasser Flora . Calcofluor-white can be used to stain thecal plates in armoured dinoflagellates. Dinoflagellates are found in all aquatic environments: marine, brackish, and fresh water, including in snow or ice. They are also common in benthic environments and sea ice. All Zooxanthellae are dinoflagellates and most of them are members within Symbiodiniaceae (e.g.

9512-590: The more dominant phytoplankton and reflect a larger portion of the biomass . In the early twentieth century, Alfred C. Redfield found the similarity of the phytoplankton's elemental composition to the major dissolved nutrients in the deep ocean. Redfield proposed that the ratio of carbon to nitrogen to phosphorus (106:16:1) in the ocean was controlled by the phytoplankton's requirements, as phytoplankton subsequently release nitrogen and phosphorus as they are remineralized. This so-called " Redfield ratio " in describing stoichiometry of phytoplankton and seawater has become

9628-446: The number of different species within a given area. This increase in plankton diversity is traced to warming ocean temperatures. In addition to species richness changes, the locations where phytoplankton are distributed are expected to shift towards the Earth's poles. Such movement may disrupt ecosystems, because phytoplankton are consumed by zooplankton, which in turn sustain fisheries. This shift in phytoplankton location may also diminish

9744-499: The ocean. Controversy about manipulating the ecosystem and the efficiency of iron fertilization has slowed such experiments. The ocean science community still has a divided attitude toward the study of iron fertilization as a potential marine Carbon Dioxide Removal (mCDR) approach. Phytoplankton depend on B vitamins for survival. Areas in the ocean have been identified as having a major lack of some B Vitamins, and correspondingly, phytoplankton. The effects of anthropogenic warming on

9860-511: The oceans such as the Southern Ocean , phytoplankton are often limited by the lack of the micronutrient iron . This has led to some scientists advocating iron fertilization as a means to counteract the accumulation of human-produced carbon dioxide (CO 2 ) in the atmosphere . Large-scale experiments have added iron (usually as salts such as ferrous sulfate ) to the oceans to promote phytoplankton growth and draw atmospheric CO 2 into

9976-522: The only other dinoflagellate genera known to use this particular feeding mechanism. Katodinium (Gymnodinium) fungiforme , commonly found as a contaminant in algal or ciliate cultures, feeds by attaching to its prey and ingesting prey cytoplasm through an extensible peduncle. Two related species, polykrikos kofoidii and neatodinium, shoots out a harpoon-like organelle to capture prey. Some mixotrophic dinoflagellates are able to produce neurotoxins that have anti-grazing effects on larger copepods and enhance

10092-408: The order Gymnodiniales , suborder Actiniscineae . The formation of thecal plates has been studied in detail through ultrastructural studies. 'Core dinoflagellates' ( dinokaryotes ) have a peculiar form of nucleus , called a dinokaryon , in which the chromosomes are attached to the nuclear membrane . These carry reduced number of histones . In place of histones, dinoflagellate nuclei contain

10208-464: The original peridinin plastids or new plastids acquired from other lineages of unicellular algae through endosymbiosis. The remaining species have lost their photosynthetic abilities and have adapted to a heterotrophic, parasitic or kleptoplastic lifestyle. Most (but not all) dinoflagellates have a dinokaryon , described below (see: Life cycle , below). Dinoflagellates with a dinokaryon are classified under Dinokaryota , while dinoflagellates without

10324-420: The oxygen production despite amounting to only ~1% of global plant biomass. In comparison with terrestrial plants, marine phytoplankton are distributed over a larger surface area, are exposed to less seasonal variation and have markedly faster turnover rates than trees (days versus decades). Therefore, phytoplankton respond rapidly on a global scale to climate variations. These characteristics are important when one

10440-426: The past century, but these conclusions have been questioned because of the limited availability of long-term phytoplankton data, methodological differences in data generation and the large annual and decadal variability in phytoplankton production. Moreover, other studies suggest a global increase in oceanic phytoplankton production and changes in specific regions or specific phytoplankton groups. The global Sea Ice Index

10556-487: The poles. Phytoplankton release dissolved organic carbon (DOC) into the ocean. Since phytoplankton are the basis of marine food webs , they serve as prey for zooplankton , fish larvae and other heterotrophic organisms. They can also be degraded by bacteria or by viral lysis . Although some phytoplankton cells, such as dinoflagellates , are able to migrate vertically, they are still incapable of actively moving against currents, so they slowly sink and ultimately fertilize

10672-837: The population of cloud condensation nuclei , mostly leading to increased cloud cover and cloud albedo according to the so-called CLAW hypothesis . Different types of phytoplankton support different trophic levels within varying ecosystems. In oligotrophic oceanic regions such as the Sargasso Sea or the South Pacific Gyre , phytoplankton is dominated by the small sized cells, called picoplankton and nanoplankton (also referred to as picoflagellates and nanoflagellates), mostly composed of cyanobacteria ( Prochlorococcus , Synechococcus ) and picoeucaryotes such as Micromonas . Within more productive ecosystems, dominated by upwelling or high terrestrial inputs, larger dinoflagellates are

10788-641: The predator more vulnerable to predation from higher trophic levels. Bioluminescent dinoflagellate ecosystem bays are among the rarest and most fragile, with the most famous ones being the Bioluminescent Bay in La Parguera, Lajas , Puerto Rico; Mosquito Bay in Vieques, Puerto Rico ; and Las Cabezas de San Juan Reserva Natural Fajardo, Puerto Rico . Also, a bioluminescent lagoon is near Montego Bay, Jamaica, and bioluminescent harbors surround Castine, Maine. Within

10904-400: The rate of oxygenic photosynthesis by cyanobacteria . Photoautotrophs evolved from heterotrophic bacteria by developing photosynthesis . The earliest photosynthetic bacteria used hydrogen sulphide . Due to the scarcity of hydrogen sulphide, some photosynthetic bacteria evolved to use water in photosynthesis, leading to cyanobacteria . Some organisms rely on organic compounds as

11020-485: The raw materials and fuel they need. Heterotrophs obtain energy by breaking down carbohydrates or oxidizing organic molecules (carbohydrates, fats, and proteins) obtained in food. Carnivorous organisms rely on autotrophs indirectly, as the nutrients obtained from their heterotrophic prey come from autotrophs they have consumed. Most ecosystems are supported by the autotrophic primary production of plants and cyanobacteria that capture photons initially released by

11136-414: The role of cyst stages, many gaps remain in knowledge about their origin and functionality. Recognition of the capacity of dinoflagellates to encyst dates back to the early 20th century, in biostratigraphic studies of fossil dinoflagellate cysts. Paul Reinsch was the first to identify cysts as the fossilized remains of dinoflagellates. Later, cyst formation from gamete fusion was reported, which led to

11252-567: The role of phytoplankton aerosol emissions on Earth's energy budget. NAAMES was designed to target specific phases of the annual phytoplankton cycle: minimum, climax and the intermediary decreasing and increasing biomass, in order to resolve debates on the timing of bloom formations and the patterns driving annual bloom re-creation. The NAAMES project also investigated the quantity, size, and composition of aerosols generated by primary production in order to understand how phytoplankton bloom cycles affect cloud formations and climate. Phytoplankton are

11368-406: The sea surface. Dinoflagellate bioluminescence is controlled by a circadian clock and only occurs at night. Luminescent and nonluminescent strains can occur in the same species. The number of scintillons is higher during night than during day, and breaks down during the end of the night, at the time of maximal bioluminescence. The luciferin-luciferase reaction responsible for the bioluminescence

11484-487: The seafloor with dead cells and detritus . Phytoplankton are crucially dependent on a number of nutrients . These are primarily macronutrients such as nitrate , phosphate or silicic acid , which are required in relatively large quantities for growth. Their availability in the surface ocean is governed by the balance between the so-called biological pump and upwelling of deep, nutrient-rich waters. The stoichiometric nutrient composition of phytoplankton drives — and

11600-431: The sediments for long periods of time. Exogenously, germination is only possible within a window of favorable environmental conditions. Yet, with the discovery that planozygotes were also able to divide it became apparent that the complexity of dinoflagellate life cycles was greater than originally thought. Following corroboration of this behavior in several species, the capacity of dinoflagellate sexual phases to restore

11716-469: The smallest known eye. Some athecate species have an internal skeleton consisting of two star-like siliceous elements that has an unknown function, and can be found as microfossils . Tappan gave a survey of dinoflagellates with internal skeletons . This included the first detailed description of the pentasters in Actiniscus pentasterias , based on scanning electron microscopy . They are placed within

11832-401: The so-called cingulum (or cigulum) runs around the cell, thus dividing it into an anterior (episoma) and posterior (hyposoma). If and only if a theca is present, the parts are called epitheca and hypotheca, respectively. Posteriorly, starting from the transverse groove, there is a longitudinal furrow called the sulcus. The transverse flagellum strikes in the cingulum, the longitudinal flagellum in

11948-516: The soil. Aquatic algae are a significant contributor to food webs in tropical rivers and streams. This is displayed by net primary production, a fundamental ecological process that reflects the amount of carbon that is synthesized within an ecosystem. This carbon ultimately becomes available to consumers. Net primary production displays that the rates of in-stream primary production in tropical regions are at least an order of magnitude greater than in similar temperate systems. Researchers believe that

12064-430: The structure of the phytoplankton, such as a significant reduction in biomass and phytoplankton density, particularly during El Nino phases can occur. The sensitivity of phytoplankton to environmental changes is why they are often used as indicators of estuarine and coastal ecological condition and health. To study these events satellite ocean color observations are used to observe these changes. Satellite images help to have

12180-406: The sulcal region of the cell (either via water currents set up by the flagella or via pseudopodial extensions) and ingest the prey through the sulcus. In several Protoperidinium spp., e.g. P. conicum , a large feeding veil—a pseudopod called the pallium—is extruded to capture prey which is subsequently digested extracellularly (= pallium-feeding). Oblea , Zygabikodinium , and Diplopsalis are

12296-452: The sulcus. Together with various other structural and genetic details, this organization indicates a close relationship between the dinoflagellates, the Apicomplexa , and ciliates , collectively referred to as the alveolates . Dinoflagellate tabulations can be grouped into six "tabulation types": gymnodinoid , suessoid , gonyaulacoid – peridinioid , nannoceratopsioid , dinophysioid , and prorocentroid . Most Dinoflagellates have

12412-406: The sun, so they live in the well-lit surface layers ( euphotic zone ) of oceans and lakes. In comparison with terrestrial plants, phytoplankton are distributed over a larger surface area, are exposed to less seasonal variation and have markedly faster turnover rates than trees (days versus decades). As a result, phytoplankton respond rapidly on a global scale to climate variations. Phytoplankton form

12528-415: The two flagella are differentiated as in dinokonts, but they are not associated with grooves. Dinoflagellates have a complex cell covering called an amphiesma or cortex, composed of a series of membranes, flattened vesicles called alveoli (= amphiesmal vesicles) and related structures. In thecate ("armoured") dinoflagellates, these support overlapping cellulose plates to create a sort of armor called

12644-456: The two groups, but none of the more basal lines has them. All the same, the dinoflagellate cell consists of the more common organelles such as rough and smooth endoplasmic reticulum , Golgi apparatus , mitochondria , lipid and starch grains, and food vacuoles . Some have even been found with a light-sensitive organelle, the eyespot or stigma , or a larger nucleus containing a prominent nucleolus . The dinoflagellate Erythropsidinium has

12760-498: The upper sunlit layer of marine and fresh water bodies of water on Earth. Paralleling plants on land, phytoplankton undertake primary production in water, creating organic compounds from carbon dioxide dissolved in the water. Phytoplankton form the base of — and sustain — the aquatic food web , and are crucial players in the Earth's carbon cycle . Phytoplankton are very diverse, comprising photosynthesizing bacteria ( cyanobacteria ) and various unicellular protist groups (notably

12876-445: The various environmental factors that together affect phytoplankton productivity . All of these factors are expected to undergo significant changes in the future ocean due to global change. Global warming simulations predict oceanic temperature increase; dramatic changes in oceanic stratification , circulation and changes in cloud cover and sea ice, resulting in an increased light supply to the ocean surface. Also, reduced nutrient supply

12992-506: The ventral cell side (dinokont flagellation). They have a ribbon-like transverse flagellum with multiple waves that beats to the cell's left, and a more conventional one, the longitudinal flagellum, that beats posteriorly. The transverse flagellum is a wavy ribbon in which only the outer edge undulates from base to tip, due to the action of the axoneme which runs along it. The axonemal edge has simple hairs that can be of varying lengths. The flagellar movement produces forward propulsion and also

13108-469: The wavelength of light different efficiently and the light is not a single ecological resource but a multitude of resources depending on its spectral composition. By that it was found that changes in the spectrum of light alone can alter natural phytoplankton communities even if the same intensity is available. For growth, phytoplankton cells additionally depend on nutrients, which enter the ocean by rivers, continental weathering, and glacial ice meltwater on

13224-399: The world ocean using ocean-colour data from satellites, and found the calorific value of phytoplankton to vary considerably across different oceanic regions and between different time of the year. The production of phytoplankton under artificial conditions is itself a form of aquaculture. Phytoplankton is cultured for a variety of purposes, including foodstock for other aquacultured organisms,

13340-426: Was coincident with evolutionary theories about the origin of eukaryotic cell fusion and sexuality, which postulated advantages for species with diploid resting stages, in their ability to withstand nutrient stress and mutational UV radiation through recombinational repair, and for those with haploid vegetative stages, as asexual division doubles the number of cells. Nonetheless, certain environmental conditions may limit

13456-536: Was once considered to be an intermediate between the nucleoid region of prokaryotes and the true nuclei of eukaryotes , so were termed " mesokaryotic ", but now are considered derived rather than primitive traits (i. e. ancestors of dinoflagellates had typical eukaryotic nuclei). In addition to dinokaryotes, DVNPs can be found in a group of basal dinoflagellates (known as Marine Alveolates , "MALVs") that branch as sister to dinokaryotes ( Syndiniales ). Dinoflagellates are protists and have been classified using both

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