Are dinoflagellates harmful to humans?
Dinoflagellates can be harmful to humans if they eat fish that have been contaminated with the toxins they release. It can cause vomiting, dizzines...
What is the function of dinoflagellates?
Dinoflagellates are sometimes endosymbionts. This means that they live within another organism and the two help each other thrive. It is a mutually...
How do I get rid of dinoflagellates in a reef tank?
To prevent dinoflagellates from overtaking the reef tank in the first place, be careful not to over-clean. Some ways to get rid of them are siphoni...
Are dinoflagellates animals or plants?
Dinoflagellates are not plants or animals; they are single celled organisms. They have plant-like characteristics such as photosynthesis and cellul...
What are dinoflagellates known for?
Dinoflagellates are known for causing red tide, bioluminescence, and releasing dangerous toxins in the water. There are thousands of different spec...
What is the classification of dinoflagellates?
Dinoflagellates are then classified into many orders, genus and species based on characteristics such as feeding behavior, composition of their outer plate, overall anatomy and physiology.
What are dinoflagellates made of?
Dinoflagellates are encrusted with plates made of a cellulose-like material and silica. Most dinoflagellates contain the pigments chlorophyll-a, chlorophyll-c and carotenoids, which allow them to undergo the process of photosynthesis to generate energy. Some species of dinoflagellates secrete toxins into the water.
What is the name of the species that eats plankton?
This species is commonly referred to as sea sparkle because it exhibits bioluminescence and becomes particularly bright when disturbed in the water.
What are unicellular eukaryotic organisms with flagella used for movement?
Dinoflagellates. unicellular eukaryotic organisms with flagella used for movement, can be found in marine and freshwater environments. Photosynthetic. synthesize food from carbon dioxide and water. Heterotrophic. organisms that do not synthesize their own food.
How do dinoflagellates reproduce?
Dinoflagellates essentially have two means of reproduction. During normal conditions, they reproduce just like any cell, by asexual division. This means that new dinoflagellates break off from old dinoflagellates and grow into a separate organism.
What are the properties of dinoflagellates?
Others are heterotrophic, meaning they cannot synthesize their own food. Some dinoflagellates have luminescent properties that make the sea appear to sparkle at night.
Is a dinoflagellate an autotroph?
Dinoflagellates are unicellular protists found floating in bodies of fresh or saltwater. They can be either photosynthetic autotrophs or heterotrophs, and they normally reproduce asexual ly unless conditions are unfavorable. There are a remarkable variety of dinoflagellates in the world, and they are able to have big impacts on their environment by releasing toxins or through bioluminescence.
What supergroup are dinoflagellates in?
Dinoflagellates are kept in the supergroup Chromalveolata, they seem to have originated from the secondary symbiosis of red algae. The group Alveolata is characterised by the presence of similar ribosomal DNA sequence and alveoli, which is a flattened vesicle present inside the plasma membrane.
How many flagella are there in a dinoflagellate?
Dinoflagellates typically have two flagella. One of the flagella wraps around the transverse groove like a belt and the other flagellum projects behind the cell and present in the longitudinal groove, that is perpendicular to the transverse groove. Dinoflagellates move like a spinning top with the help of flagella.
What are some examples of bioluminescent dinoflagellate?
Examples of the ecosystem having bioluminescent dinoflagellate are: 3 of the 5 bioluminescent bays are present in Puerto Rico, Montego Bay in Jamaica and Indian river Lagoon in Central Florida.
What are the two types of protists that make up the Dinoflagellate?
Dinoflagellates . Dinoflagellates are unicellular protists comprising two flagella. Dinoflagellates are mostly marine plankton, but also found in freshwater habitats. Photosynthetic dinoflagellates form one of the largest group of eukaryotic algae apart from diatoms. Dinoflagellates have characteristics of both plants and animals.
Why do dinoflagellates multiply?
Dinoflagellates sometimes multiply rapidly, resulting in population explosions or blooms. Bloom may contain more than a million cells per ml of water. Rapid multiplication is due to the presence of abundant nutrient present in the water. This might be due to human activities or other natural reasons.
What species of dinoflagellates cause red tide?
The species of dinoflagellates causing red tide are: Karenia brevis causing red tide in the Gulf of Mexico produces a neurotoxin called brevetoxin. Alexendrium fundyense is responsible for the red tide in the Gulf of Maine, produces a toxin named saxitoxin. Pfiesteria is a colourless dinoflagellate causing the toxic bloom.
What is the flash of light that a dinoflagellate emits?
Blooms of dinoflagellates emit short flashes of light when disturbed mechanically by waves, ships or swimming. This appears as a bluish flicker in the ocean water at night.
What is a dinoflagellate?
Neither plant nor animal, dinoflagellates are unicellular protists; most exhibit the following characteristics:
Why is the water in the Dinoflagellate red tide brown?
For dinoflagellate red tides, the water is discolored red or brown due to as high as 20 million cells per liter.
What are the neurotoxins in shellfish?
There are several types of neurotoxins produced by dinoflagellates. These chemicals may affect nerve action by interfering with the movement of ions across cell membranes, thus affecting muscle activity. The toxin saxitoxin, produced by Gonyaulax off the west coast of North America, and Alexandrium off the northeast coast, accumulates in shellfish. Eating contaminated shellfish causes paralytic shellfish poisoning (PSP). The worst cases of PSP result in respiratory failure and death within 12 hours. Another toxin that accumulates in shellfish is brevetoxin, produced by the dinoflagellate Karenia brevis. Brevetoxin is unique in that it becomes aerosolized when the dinoflagellates end up in the surf zone and then blows onto the beach causing respiratory irritation in humans. If you are on a beach on the Gulf coast of Florida and notice asthma-like breathing symptoms, chances are you are experiencing toxicity from a Karenia bloom. A toxin produced by the dinoflagellate Dinophysis causes diarrhetic shellfish poisoning (DSP), which results in digestive upset but which is not fatal. Ciguatera is another form of dinoflagellate toxicity in tropical areas caused by eating fish contaminated by toxins of the dinoflagellate Gambierdiscus toxicus.
What are the genera of Dinoflagellate?
For additional information on specific dinoflagellate genera, seeCeratium, Gonyaulax, Gymnodinium, Noctiluca, and Peridinium.
How big are dinoflagellates?
Dinoflagellates range in size from about 5 to 2,000 micrometres (0.0002 to 0.08 inch). Most are microscopic, but some form visible colonies. Nutrition among dinoflagellates is autotrophic, heterotrophic, or mixed; some species are parasitic or commensal.
What is the groove of a dinoflagellate cell?
The dinoflagellate cell is banded by a median or coiled groove, the annulus, which contains a flagellum. A longitudinal groove, the sulcus, extends from the annulus posteriorly to the point at which a second flagellum is attached. The nuclei of dinoflagellates are larger than those of other eukaryotes. So-called armoured dinoflagellates are covered with celluloseplates, which may have long spiny extensions; some species lacking armour have a thin pellicle (protective layer). Photosynthetic dinoflagellates have yellowish or brownish plastids (pigment-containing bodies) and may store food in the form of starches, starchlike compounds, or oils.
What is a photosynthetic dinoflagellate?
Photosynthetic dinoflagellates have yellowish or brownish plastids (pigment-containing bodies) and may store food in the form of starches, starchlike compounds, or oils. The dinoflagellate Ceratium tripos (magnified). Get a Britannica Premium subscription and gain access to exclusive content. Subscribe Now.
What is sea sparkle?
A species of dinoflagellate known as Noctiluca scintillans, commonly called sea sparkle, is a type of algae that can aggregate into an algal bloom, producing substances that are potentially toxic to marine life.
Which cell is banded by a median or coiled groove, the annulus, which contains a?
Douglas P. Wilson. The dinoflagellate cell is banded by a median or coiled groove, the annulus, which contains a flagellum. A longitudinal groove, the sulcus, extends from the annulus posteriorly to the point at which a second flagellum is attached. The nuclei of dinoflagellates are larger than those of other eukaryotes.
Do dinoflagellates live in freshwater?
Most are marine, though some live in freshwater habitats. The group is an important component of phytoplankton in all but the colder seas and is an important link in the food chain. Dinoflagellates also produce some of the bioluminescence sometimes seen in the sea.
What is a dinoflagellate?
Dinoflagellates are a group of unicellular protists that can be identified using the light microscope, and are (usually) recognized by their golden-brown plastids, assimilative cell with indented waist, distinctive swimming pattern, and relatively large nucleus that contains visible chromosomes.
What are the characteristics of a dinoflagellate?
Dinoflagellates are a monophyletic group of primarily unicellular organisms united by a suite of unique characteristics, including flagellar insertion, pigmentation, organelles, and features of the nucleus, that distinguish them from other groups. The name dinoflagellate comes from dinos (Greek) “whirling,” which describes their distinctive ...
How many species of dinoflagellate are there in the east coast?
The dinoflagellate species diversity in the east coast estuaries is relatively low (15 species in seven families) compared with the west coast estuaries (76 species from 10 families). The family Dinophyceae is dominant with 18 species, followed by Peridiniaceae and Ceratiaceae, with 13 and 10 species, respectively.
How do dinoflagellates reproduce?
The reproduction of dinoflagellates is most commonly asexual by mitosis. In the blooming period, vegetative cell divisions occur at a rate of about one per day. Sexual reproduction is also observed for many species. When blooming, dinoflagellates can be responsible for ‘red tides,’ so called because the large density of cells in the surface water induces a color change (green, brown, or red). Many dinoflagellates are bioluminescent and cause a glow at the sea surface by night. A few dinoflagellate species produce neurotoxins that may be bioconcentrated by filtering organisms, notably shellfish, which then become poisonous and dangerous for the health of animals (or people) that eat them.
Why is the nucleus of a dinoflagellate considered a mesokaryotic nucle?
Dodge (1966) termed the dinoflagellate nucleus “mesokaryotic” because it possessed characters intermediate between the coiled DNA areas (2.5 nm) of prokaryotic bacteria and the well-defined eukaryotic nucleus . The 1N nucleus in nonparasitic species has condensed, banded chromosomes during interphase, a permanent nuclear envelope, a permanent nucleolus, and chromosomes attached to the nuclear envelope. The chromosomes are mostly DNA as demonstrated in electron micrographs in which the application of DNAase left little residue (Leadbeater, 1967). Biochemical analyses reveal the absence of typical histones and nucleosomes in most dinoflagellates analyzed although some basic nuclear proteins are present ( Rizzo, 1987 ). Mitotic division, in most free-living species, is typically endonuclear starting with microtubules invading cytoplasmic channels and ending with typical anaphase and telophase.
What is the name of the group of organisms that are unicellular?
Dinoflagellates (Division or Phylum Pyrrhophyta) are a group of primarily unicellular organisms united by a suite of unique characteristics, including flagellar insertion, pigmentation, organelles, and features of the nucleus, that distinguishes them from other groups. The name dinoflagellate comes from dinos (Greek), ...
Why do dinoflagellates glow?
Many dinoflagellates are bioluminescent and cause a glow at the sea surface by night. A few dinoflagellate species produce neurotoxins that may be bioconcentrated by filtering organisms, notably shellfish, which then become poisonous and dangerous for the health of animals (or people) that eat them.
How are dinoflagellates classified?
Dinoflagellates, composed of some 1,200 to 2,000 species in 130 or more genera, are classified in the Phylum Dinoflagellata and the division Pyrrophyta. Their name comes from the Greek word dinos, meaning "whirling," with the latter part of their name derived from the characteristic flagella they possess. The dinoflagellates, about half of which are photosynthetic and some of which are bioluminescent, are important components of oceanic primary productivity. They are found dispersed in all oceans and all ocean zones, and can exist in pelagic or benthic zones or within host tissues. A small percentage of them are freshwater species. They are perhaps well-known as parasites or pathogens, and some are even symbionts of invertebrate hosts. Dinoflagellates may be capable of moving and swimming (all live in aquatic environments) using two flagella. These flagella, one oriented around the cell (the transverse flagellum), and the other oriented toward the posterior (the longitudinal flagellum) are the diagnostic criteria of this group.
What are the features of dinoflagellates?
Many have numerous structures near the periphery of their cell interior called trichocysts, features similar to those found in ciliates. They are discharged by rapid hydration and are thought to function in protection, toxin discharge, secretion or prey capture. Another feature found in some species are mucocysts, located directly below the cell membrane, which eject mucilagenous material that may aid cells in adhering to substrates, or may function in prey capture. A third type of ejectile organelle is found in some species. These are the cnidocysts, and are very similar in structure to cnidarian nematocysts. They are less numerous than trichocysts and their function is unknown, but they are believed to be involved in defense or prey capture. Other unusual cellular inclusions in dinoflagellates may include a peduncle, pusule, eyespots, virus-like particles, paranuclear bodies and others, and are reviewed by Spector (1994).
What are the fish parasites in the aquarium called?
Dinoflagellates in the Aquarium: "Snotty" Dinoflagellates and Fish Parasites
What is the outer covering of a dinoflagellate?
Dinoflagellates typically have an outer covering called the theca, or amphiesma , from which descriptive features can be ascertained. Two broad groups of dinoflagellates can be distinguished by the presence or absence of well-developed cellulose-containing thecal plates, and these groups are termed armored dinoflagellates or unarmored (naked) dinoflagellates, respectively. The theca may be divided into two parts by a transverse groove called the girdle, or cingulum, that rings the cell. The part of the theca above the girdle is the epitheca, and the part below is the hypotheca. The girdle is the location of the transverse flagellum. Another groove, the sulcus, runs longitudinally and is the location for attachment of the longitudinal flagellum. The cell's anterior end, the apex, may have an apical pore complex in armored dinoflagellates, the function of which is unknown. The posterior end of the cell, the antapex, often has projecting spines or protuberances. The theca can be shed, regenerated, or remain undeveloped during a dinoflagellate's various life stages.
What is a noctiluca?
Here is an image of some Noctiluca, probably N. miliaris. These are purportedly the largest dinoflagellates. They lack chlorophyll, and eat smaller protozoans. They are also brilliantly bioluminescent, a fact alluded to by their name as "noctiluca" means "night light." They are shaped rather like a lily pad, and what appear to be "threads" in this image are the large flagella that are used in prey capture. Photo and caption by Ronald Shimek.
Where are pigments found in corals?
Table 1. Pigments found to be contained within zooxanthellae of corals, comprising numerous species of dinoflagellates.
Do dinoflagellates have chromosomes?
Still other unusual features exist in dinoflagellates. In almost every species, nuclear chromosomes are permanently condensed in a condition that is similar to what is normally seen prior to mitosis in cell nuclei in other eukaryotes. Furthermore, dinoflagellate nuclei contain many times the amount of DNA found in most other eukaryotic cells, a feature which is discussed in more depth below. At least some species are probably polyploid. Dinoflagellates can reproduce asexually or sexually. In the former case, the cell divides longitudinally by fission, maintaining a haploid state. Each haploid daughter can, however, act as a gamete. The flagellated haploid cells can laterally fuse and form a diploid zygote that can remain motile. Under unfavorable conditions, however, some dinoflagellate zygotes enlarge and thicken (the hypnozygote stage), lose motility and produce red bodies within the cell. This diploid form, called a cyst (or dinocyst), settles to the bottom of the water column and is a "resting stage" in the dinoflagellate's life cycle. The cyst can have a tough coating of a substance called sporopollenin, or it may be embedded with calcium carbonate or silica. The cysts emerge, or germinate, in a motile stage upon encountering favorable environmental conditions, with another round of division, this time by meiosis, again resulting in a haploid cell. This type of life cycle strategy is termed haplontic.
How many species of dinoflagellates are there?
There are nearly 2000 known living species of dinoflagellates, classified in about 125 genera. Relationships of the Dinoflagellata to other protists are not well known. Part of the problem is that they have many unusual features. (Click on the Morphology button to see more.)
Where did photosynthetic dinoflagellates come from?
Understanding about the origin of the photosynthetic dinoflagellates has recently come from the theory of endosymbiosis . According to this theory, all mitochondria and plastids originated as bacteria which were swallowed, but not digested. The bacteria became symbiotic with the organisms which swallowed them. This is the explanation now given for the double membrane around mitochondria and plastids -- the inner membrane is bacterial, and the outer membrane comes from the host.
