Protozoa is an informal term for single-celled eukaryotes, either free-living or parasitic, which feed on organic matter such as other microorganisms or organic tissues and debris. The protozoa were regarded as "one-celled animals", because they possess animal-like behaviors, such as motility and predation, lack a cell wall, as found in plants and many algae. Although the traditional practice of grouping protozoa with animals is no longer considered valid, the term continues to be used in a loose way to identify single-celled organisms that can move independently and feed by heterotrophy. In some systems of biological classification, Protozoa is a high-level taxonomic group; when first introduced in 1818, Protozoa was erected as a taxonomic class, but in classification schemes it was elevated to a variety of higher ranks, including phylum and kingdom. In a series of classifications proposed by Thomas Cavalier-Smith and his collaborators since 1981, Protozoa has been ranked as a kingdom; the seven-kingdom scheme presented by Ruggiero et al. in 2015, places eight phyla under Kingdom Protozoa: Euglenozoa, Metamonada, Choanozoa sensu Cavalier-Smith, Percolozoa and Sulcozoa.
Notably, this kingdom excludes several major groups of organisms traditionally placed among the protozoa, including the ciliates, dinoflagellates and the parasitic apicomplexans, all of which are classified under Kingdom Chromista. Kingdom Protozoa, as defined in this scheme, does not form a natural group or clade, but a paraphyletic group or evolutionary grade, within which the members of Fungi and Chromista are thought to have evolved; the word "protozoa" was coined in 1818 by zoologist Georg August Goldfuss, as the Greek equivalent of the German Urthiere, meaning "primitive, or original animals". Goldfuss created Protozoa as a class containing; the group included not only single-celled microorganisms but some "lower" multicellular animals, such as rotifers, sponges, jellyfish and polychaete worms. The term Protozoa is formed from the Greek words πρῶτος, meaning "first", ζῶα, plural of ζῶον, meaning "animal"; the use of Protozoa as a formal taxon has been discouraged by some researchers because the term implies kinship with animals and promotes an arbitrary separation of "animal-like" from "plant-like" organisms.
In 1848, as a result of advancements in cell theory pioneered by Theodor Schwann and Matthias Schleiden, the anatomist and zoologist C. T. von Siebold proposed that the bodies of protozoans such as ciliates and amoebae consisted of single cells, similar to those from which the multicellular tissues of plants and animals were constructed. Von Siebold redefined Protozoa to include only such unicellular forms, to the exclusion of all metazoa. At the same time, he raised the group to the level of a phylum containing two broad classes of microorganisms: Infusoria, Rhizopoda; the definition of Protozoa as a phylum or sub-kingdom composed of "unicellular animals" was adopted by the zoologist Otto Bütschli—celebrated at his centenary as the "architect of protozoology"—and the term came into wide use. As a phylum under Animalia, the Protozoa were rooted in the old "two-kingdom" classification of life, according to which all living beings were classified as either animals or plants; as long as this scheme remained dominant, the protozoa were understood to be animals and studied in departments of Zoology, while photosynthetic microorganisms and microscopic fungi—the so-called Protophyta—were assigned to the Plants, studied in departments of Botany.
Criticism of this system began in the latter half of the 19th century, with the realization that many organisms met the criteria for inclusion among both plants and animals. For example, the algae Euglena and Dinobryon have chloroplasts for photosynthesis, but can feed on organic matter and are motile. In 1860, John Hogg argued against the use of "protozoa", on the grounds that "naturalists are divided in opinion—and some will continue so—whether many of these organisms, or living beings, are animals or plants." As an alternative, he proposed a new kingdom called Primigenum, consisting of both the protozoa and unicellular algae, which he combined together under the name "Protoctista". In Hoggs's conception, the animal and plant kingdoms were likened to two great "pyramids" blending at their bases in the Kingdom Primigenum. Six years Ernst Haeckel proposed a third kingdom of life, which he named Protista. At first, Haeckel included a few multicellular organisms in this kingdom, but in work he restricted the Protista to single-celled organisms, or simple colonies whose individual cells are not differentiated into different kinds of tissues.
Despite these proposals, Protozoa emerged as the preferred taxonomic placement for heterotrophic microorganisms such as amoebae and ciliates, remained so for more than a century. In the course of the 20th century, the old "two kingdom" system began to weaken, with the growing awareness that fungi did not belong among the plants, that most of the unicellular protozoa were no more related to the animals than they were to the plants. By mid-century, some biologists, such as Herbert Copeland, Robert H. Whittaker and Lynn Margulis, advocated the revival of Haeckel's Protista or Hogg's Protoctista as a kingdom-level eukaryotic group, alongside Plants and Fungi. A variety of multi-kingdom systems were proposed, Kingdoms Protista and Protoctista became well est
In marine and reef aquariums, a calcium reactor creates a balance of alkalinity. An acidic solution is produced by injecting carbon dioxide into a chamber with salt water and calcium rich media; the carbon dioxide lowers the pH by producing a solution high in carbonic acid, dissolves calcium. The effluent is returned to the reef aquarium where the calcium is consumed by organisms corals when building skeletons. A calcium reactor is an efficient method to supply calcium to a reef aquarium. Reactors may be used in elaborate freshwater and brackish aquariums where freshwater clams and other invertebrates need a constant supply of calcium; the reactor dissolves the calcium-laden media to provide bicarbonates HCO3− and calcium ions at the sames rate as consumed during calcification. Dissolving the media requires an acidic pH. Saltwater may have a pH of 7.8 or higher, so to reduce the pH carbon dioxide is used. The reaction formula is: CaCO3 + H2O + CO2 ⟷ Ca2+ + 2 HCO3−Inside the reaction chamber, a calcium rich media CaCO3, is forced into contact with water injected with carbon dioxide in order to create carbonic acid.
This increases the solubility of the calcium carbonate. The reaction frees the calcium and carbonate, supplying the aquarium with water rich in Ca2+ and CO32−, important for maintaining alkalinity and calcium levels; the bubble counter measures carbon dioxide. The flow rate of carbon dioxide is monitored so that the dissolved gas goes into the solution, with a minimum unconsumed. A needle valve or solenoid valve regulates the CO2 bubble rate. Valves with precise adjustment abilities improve bubble control; the feed pump controls the volume of water exchange. This is important because a high rate of water flow into the reactor reduces its efficiency, thus resulting in underproduction and a waste of CO2; some reactors siphon water into the input of the reactor's re-circulation pump. A potential complication is the medium in the reactor becoming compacted, increasing back pressure onto the pump and reducing water into the reactor. Placing a gate or needle valve on the reactor's outlet side will improve flow characteristics compared to control from the inlet side.
Peristaltic pumps are effective operating against pressure, capable of supplying an adjustable and continuous flow over flow rates with minimal maintenance. The pH control is connected to a probe in the reactor and adjusts the rate at which the calcium media dissolves; this probe monitors the pH level in the calcium reactor. The pH range for the typical calcium reactor is 6.5–6.8. When the pH rises above a certain level, a valve opens, allowing carbon dioxide to enter the reactor; the control closes the valve. Some pH controllers have an interface for an air pump; this air pump is connected to an airstone in main tank. If the probe detects a low pH level, the pump activates; the bubbles raise the pH by dissipating the CO2 gas. Aquarium Protein skimmer Filter Reefkeeping.com article on calcium reactors Georgia Tech information on calcium reactor
Invertebrates are animals that neither possess nor develop a vertebral column, derived from the notochord. This includes all animals apart from the subphylum Vertebrata. Familiar examples of invertebrates include arthropods, mollusks and cnidarians; the majority of animal species are invertebrates. Many invertebrate taxa have a greater number and variety of species than the entire subphylum of Vertebrata; some of the so-called invertebrates, such as the Tunicata and Cephalochordata are more related to the vertebrates than to other invertebrates. This makes the invertebrates paraphyletic, so the term has little meaning in taxonomy; the word "invertebrate" comes from the Latin word vertebra, which means a joint in general, sometimes a joint from the spinal column of a vertebrate. The jointed aspect of vertebra is derived from the concept of turning, expressed in the root verto or vorto, to turn; the prefix in- means "not" or "without". The term invertebrates is not always precise among non-biologists since it does not describe a taxon in the same way that Arthropoda, Vertebrata or Manidae do.
Each of these terms describes a valid taxon, subphylum or family. "Invertebrata" is a term of convenience, not a taxon. The Vertebrata as a subphylum comprises such a small proportion of the Metazoa that to speak of the kingdom Animalia in terms of "Vertebrata" and "Invertebrata" has limited practicality. In the more formal taxonomy of Animalia other attributes that logically should precede the presence or absence of the vertebral column in constructing a cladogram, for example, the presence of a notochord; that would at least circumscribe the Chordata. However the notochord would be a less fundamental criterion than aspects of embryological development and symmetry or bauplan. Despite this, the concept of invertebrates as a taxon of animals has persisted for over a century among the laity, within the zoological community and in its literature it remains in use as a term of convenience for animals that are not members of the Vertebrata; the following text reflects earlier scientific understanding of the term and of those animals which have constituted it.
According to this understanding, invertebrates do not possess a skeleton of bone, either internal or external. They include hugely varied body plans. Many have like jellyfish or worms. Others have outer shells like those of insects and crustaceans; the most familiar invertebrates include the Protozoa, Coelenterata, Nematoda, Echinodermata and Arthropoda. Arthropoda include insects and arachnids. By far the largest number of described invertebrate species are insects; the following table lists the number of described extant species for major invertebrate groups as estimated in the IUCN Red List of Threatened Species, 2014.3. The IUCN estimates that 66,178 extant vertebrate species have been described, which means that over 95% of the described animal species in the world are invertebrates; the trait, common to all invertebrates is the absence of a vertebral column: this creates a distinction between invertebrates and vertebrates. The distinction is one of convenience only. Being animals, invertebrates are heterotrophs, require sustenance in the form of the consumption of other organisms.
With a few exceptions, such as the Porifera, invertebrates have bodies composed of differentiated tissues. There is typically a digestive chamber with one or two openings to the exterior; the body plans of most multicellular organisms exhibit some form of symmetry, whether radial, bilateral, or spherical. A minority, exhibit no symmetry. One example of asymmetric invertebrates includes all gastropod species; this is seen in snails and sea snails, which have helical shells. Slugs appear externally symmetrical. Other gastropods develop external asymmetry, such as Glaucus atlanticus that develops asymmetrical cerata as they mature; the origin of gastropod asymmetry is a subject of scientific debate. Other examples of asymmetry are found in hermit crabs, they have one claw much larger than the other. If a male fiddler loses its large claw, it will grow another on the opposite side after moulting. Sessile animals such as sponges are asymmetrical alongside coral colonies. Neurons differ in invertebrates from mammalian cells.
Invertebrates cells fire in response to similar stimuli as mammals, such as tissue trauma, high temperature, or changes in pH. The first invertebrate in which a neuron cell was identified was the medicinal leech, Hirudo medicinalis. Learning and memory using nociceptors in the sea hare, Aplysia has been described. Mollusk neurons are able to detect tissue trauma. Neurons have been identified in a wide range of invertebrate species, including annelids, molluscs and arthropods. One type of invertebrate respi
International Standard Serial Number
An International Standard Serial Number is an eight-digit serial number used to uniquely identify a serial publication, such as a magazine. The ISSN is helpful in distinguishing between serials with the same title. ISSN are used in ordering, interlibrary loans, other practices in connection with serial literature; the ISSN system was first drafted as an International Organization for Standardization international standard in 1971 and published as ISO 3297 in 1975. ISO subcommittee TC 46/SC 9 is responsible for maintaining the standard; when a serial with the same content is published in more than one media type, a different ISSN is assigned to each media type. For example, many serials are published both in electronic media; the ISSN system refers to these types as electronic ISSN, respectively. Conversely, as defined in ISO 3297:2007, every serial in the ISSN system is assigned a linking ISSN the same as the ISSN assigned to the serial in its first published medium, which links together all ISSNs assigned to the serial in every medium.
The format of the ISSN is an eight digit code, divided by a hyphen into two four-digit numbers. As an integer number, it can be represented by the first seven digits; the last code digit, which may be 0-9 or an X, is a check digit. Formally, the general form of the ISSN code can be expressed as follows: NNNN-NNNC where N is in the set, a digit character, C is in; the ISSN of the journal Hearing Research, for example, is 0378-5955, where the final 5 is the check digit, C=5. To calculate the check digit, the following algorithm may be used: Calculate the sum of the first seven digits of the ISSN multiplied by its position in the number, counting from the right—that is, 8, 7, 6, 5, 4, 3, 2, respectively: 0 ⋅ 8 + 3 ⋅ 7 + 7 ⋅ 6 + 8 ⋅ 5 + 5 ⋅ 4 + 9 ⋅ 3 + 5 ⋅ 2 = 0 + 21 + 42 + 40 + 20 + 27 + 10 = 160 The modulus 11 of this sum is calculated. For calculations, an upper case X in the check digit position indicates a check digit of 10. To confirm the check digit, calculate the sum of all eight digits of the ISSN multiplied by its position in the number, counting from the right.
The modulus 11 of the sum must be 0. There is an online ISSN checker. ISSN codes are assigned by a network of ISSN National Centres located at national libraries and coordinated by the ISSN International Centre based in Paris; the International Centre is an intergovernmental organization created in 1974 through an agreement between UNESCO and the French government. The International Centre maintains a database of all ISSNs assigned worldwide, the ISDS Register otherwise known as the ISSN Register. At the end of 2016, the ISSN Register contained records for 1,943,572 items. ISSN and ISBN codes are similar in concept. An ISBN might be assigned for particular issues of a serial, in addition to the ISSN code for the serial as a whole. An ISSN, unlike the ISBN code, is an anonymous identifier associated with a serial title, containing no information as to the publisher or its location. For this reason a new ISSN is assigned to a serial each time it undergoes a major title change. Since the ISSN applies to an entire serial a new identifier, the Serial Item and Contribution Identifier, was built on top of it to allow references to specific volumes, articles, or other identifiable components.
Separate ISSNs are needed for serials in different media. Thus, the print and electronic media versions of a serial need separate ISSNs. A CD-ROM version and a web version of a serial require different ISSNs since two different media are involved. However, the same ISSN can be used for different file formats of the same online serial; this "media-oriented identification" of serials made sense in the 1970s. In the 1990s and onward, with personal computers, better screens, the Web, it makes sense to consider only content, independent of media; this "content-oriented identification" of serials was a repressed demand during a decade, but no ISSN update or initiative occurred. A natural extension for ISSN, the unique-identification of the articles in the serials, was the main demand application. An alternative serials' contents model arrived with the indecs Content Model and its application, the digital object identifier, as ISSN-independent initiative, consolidated in the 2000s. Only in 2007, ISSN-L was defined in the
Daphnia, a genus of small planktonic crustaceans, are 0.2–5 millimetres in length. Daphnia are members of the order Cladocera, are one of the several small aquatic crustaceans called water fleas because their saltatory swimming style resembles the movements of fleas. Daphnia live in various aquatic environments ranging from acidic swamps to freshwater lakes and ponds; the two most available species of Daphnia are D. pulex and D. magna. They are associated with a related genus in the order Cladocera: Moina, in the Moinidae family instead of Daphniidae and is much smaller than D. pulex. Daphnia eggs for sale are enclosed in ephippia; the body of Daphnia is 1–5 millimetres long, is divided into segments, although this division is not visible. The head is fused, is bent down towards the body with a visible notch separating the two. In most species, the rest of the body is covered by a carapace, with a ventral gap in which the five or six pairs of legs lie; the most prominent features are the compound eyes, the second antennae, a pair of abdominal setae.
In many species, the carapace is translucent or nearly so and as a result they make excellent subjects for the microscope as one can observe the beating heart. Under low-power microscopy, the feeding mechanism can be observed, with immature young moving in the brood pouch; the heart is at the top of the back, just behind the head, the average heart rate is 180 bpm under normal conditions. Daphnia, like many animals, are prone to alcohol intoxication, make excellent subjects for studying the effects of the depressant on the nervous system due to the translucent exoskeleton and the visibly altered heart rate, they are tolerant of being observed live under a cover slip and appear to suffer no harm when returned to open water. This experiment can be performed using caffeine, nicotine or adrenaline, each producing an increase in the heart rate. Due to its intermediate size, Daphnia utilizes both diffusion and circulatory methods, producing hemoglobin in low-oxygen environments. Daphnia is a large genus – comprising over 200 species – belonging to the cladoceran family Daphniidae.
It is subdivided into several subgenera, but the division has been controversial and is still in development. Each subgenus has been further divided into a number of species complexes; the understanding of species boundaries has been hindered by phenotypic plasticity, intercontinental introductions and poor taxonomic descriptions. Daphnia species are r-selected, meaning that they invest in early reproduction and so have short lifespans. An individual Daphnia life-span depends on factors such as temperature and the abundance of predators, but can be 13–14 months in some cold, oligotrophic fish-free lakes. In typical conditions, the life cycle is much shorter, not exceeding 5–6 months. Daphnia are filter feeders, ingesting unicellular algae and various sorts of organic detritus including protists and bacteria Beating of the legs produces a constant current through the carapace which brings such material into the digestive tract; the trapped food particles are formed into a food bolus which moves down the digestive tract until voided through the anus located on the ventral surface of the terminal appendage.
The second and third pair of legs are used in the organisms' filter feeding, ensuring large unabsorbable particles are kept out, while the other sets of legs create the stream of water rushing into the organism. Swimming is powered by the second set of antennae, which are larger in size than the first set; the action of this second set of antennae is responsible for the jumping motion. Most Daphnia species have a life cycle based on "cyclical parthenogenesis", alternating between parthenogenetic reproduction and sexual reproduction. For most of the growth season, females reproduce asexually, they produce. Under typical conditions, these eggs hatch after a day, remain in the female's brood pouch for around three days, they are released into the water, pass through a further 4–6 instars over 5–10 days before reaching an age where they are able to reproduce. The asexually produced offspring are female. Towards the end of the growing season, the mode of reproduction changes, the females produce tough "resting eggs" or "winter eggs".
When environmental condition deteriorate, some of the asexually produced offspring develop into males. The females start producing haploid sexual eggs. In species without males, resting eggs are produced asexually and are diploid. In either case, the resting eggs are protected by a hardened coat called the ephippium, are cast off at the female's next moult; the ephippia can withstand periods of extreme cold, drought or lack of food availability, hatch – when conditions improve – into females. Several Daphnia species are considered threatened; the following are listed as vulnerable by IUCN: Daphnia nivalis, Daphnia coronata, Daphnia occidentalis, Daphnia jollyi. Some species
A freshwater aquarium is a receptacle that holds one or more freshwater aquatic organisms for decorative, pet-keeping, or research purposes. Modern aquariums are most made from transparent glass or acrylic glass. Typical inhabitants include fish, plants and invertebrates, such as snails and crustaceans. Freshwater fish may be tropical species. Although freshwater aquariums can be set up as community tanks and tropical fish are not mixed due to incompatibilities in temperature requirements. Coldwater aquariums other species that do not require a heating apparatus. Warmer temperatures would increase their metabolism and shorten their lifespan. For a tropical fish tank, maintaining a warm environmental temperature ranging between 75 and 80 °F enables the fish to thrive. Aquariums may be decorated with sand or gravel, live or plastic plants, rocks, a variety of commercially made plastic sculptures; the smallest aquariums are fish bowls, but these are not recommended for most fish as they are too small, tend to stunt fish growth, may lead to eventual death.
The earliest known aquariums were artificial fish ponds constructed by the ancient Sumerians over 4500 years ago. The ancient Assyrians and Romans kept fish in ponds for food and entertainment purposes; the ancient Chinese were the first culture to breed fish with any degree of success. They raised carp for food around 2000 BC, developed ornamental goldfish by selective breeding. Goldfish were introduced to Europe during the 18th century. In the 18th century, widespread public interest in the study of nature was awakening, fish were kept in glass jars, porcelain containers, wooden tubs, small artificial ponds, it was during this time that zoologist and botanist, Johann Matthaeus Bechstein, kept a large number of fishes and amphibians and laid down the foundation for aquarium and terrarium science. The concepts of the proper aquarium and terrarium were developed by Nathaniel Bagshaw Ward in 1829. During the 19th century the idea of the "balanced aquarium" was developed; this approach was an attempt to mimic a balanced ecosystem in nature.
According to this method, fish waste could be consumed by plants, plants along with the air surface of the water could supply oxygen for the fish. In 1869, the first tropical fish was imported from Asia. In these days, tropical tanks were kept warm by an open flame; because early filters were noisy and expensive, fishkeeping was a hobby reserved for wealthy, scientifically inclined individuals. In 1878, Rear-Admiral Daniel Ammon brought the first tropical fish from the Far East to the United States which led to a decline in the popularity of goldfish. In the early 20th century, aeration, as well as particulate and charcoal filtration was introduced; the undergravel filter was introduced in the 1950s. By this time, the old idea of the balanced aquarium was viewed as unattainable and unnecessary by many people in the aquarium hobby, but it made a comeback at the end of the 20th Century with the rising popularity of the planted tank. Today fishkeeping has become a popular hobby that anyone can do.
Aquarium fish bred in Asia and Florida. Captive-bred species are inexpensive and available, are less to be infected with diseases or parasites. Successive generations of inbred fish have less color and sport smaller fins than their wild counterparts. A typical household freshwater aquarium set-up, apart from its aquatic tenants, consists of furnishings such as a gravel substrate, live or plastic plants, driftwood, a backcloth or background, other decorations. Other equipment includes a canopy or hood as an aquarium cover, an aquarium stand or base, lighting accessories, a heater, a thermometer, air pumps, filtration apparatus, fish food, a fish net, water conditioner, water quality testing kits, a siphon hose or gravel cleaner, a bucket for water changes. Surface area and height are important in the maintenance of a living biotope; the surface area contributes to providing superior in-tank oxygenation and it facilitates the creation of attractive aquatic themes. Freshwater environments benefit more from short and wide aquariums, due to the larger surface area they present to the air.
In general, a larger-sized aquarium provides a more stable water-world and the hobbyist can acquire a greater number of fish. A large aquarium can enhance aesthetic value. With regards to material, an all-glass aquarium is preferable due to its reasonable cost and its superior ability to resist scratches and discoloration. Indoor aquariums are placed far from windows and cooling ducts of the house because direct sunlight and temperature changes can negatively affect the aquatic environment. Overexposure to sunlight leads to rapid algae growth outside the tank. Sudden temperature variations are harmful to fish. Fish come from several different geographical regions. Most aquarium fish originated in South America, Africa, or Asia. Fish can be kept in different combinations of species and in different kinds of aquatic environments. Four common themes include the community aquarium, the goldfish aquarium, the African cichlid aquarium, the planted aquarium. A community aquarium refers to the mixing of fish and plants from different geographical areas with an emphasisis on the color and hardiness of the specimens.
An example would be the combination of gouramis and rasboras with a selection of hardy plants such as Hygrophila dif
Live rock is rock from the ocean, introduced into a saltwater aquarium. Along with live sand, it confers to the closed marine system multiple benefits desired by the saltwater aquarium hobbyist; the name sometimes leads to misunderstandings, as the "live rock" itself is not alive, but rather is made from the aragonite skeletons of long dead corals, or other calcareous organisms, which in the ocean form the majority of coral reefs. When taken from the ocean it is encrusted with coralline algae and inhabited by a multitude of marine organisms; the many forms of micro and macroscopic marine life that live on and inside of the rock, which acts as an ideal habitat, give it the name "live rock". Live rock is harvested for use in the aquarium trade from collections in the wild near reefs, where parts may become detached from the central body of coral by storms, it may be "seeded" from small coralline rocks by an aquaculturalist in warm ocean water, to be harvested later. Live rock can be seeded by adding base rock to an active reef aquarium that has live rock.
Live rock harbors a wide variety of corals, algae and other invertebrates, when they are collected. Corals added to the aquarium will become attached to the rock. Live rock is valued in the aquarium trade, it introduces a diverse array of bacteria and invertebrates to the closed marine environment and functions as a superior biological filter that hosts aerobic and anaerobic nitrifying bacteria required for the nitrogen cycle that processes waste. Live rock becomes the main biological nitrification base or biological filter of a saltwater aquarium. Additionally, live rocks have a stabilizing effect on the water chemistry, in particular on helping to maintain constant pH by release of calcium carbonate. Lastly, live rock when encrusted with multiple colors of coralline algae, becomes a major decorative element of the aquarium and provides shelter for the inhabitants, it is used to build caves, overhangs, or other structures in the tank, a practice known as aquascaping. In J. Charles Delbeek's article Your First Reef Aquarium, he states, Live rock must however be cured prior to aquarium installation.
Many of the organisms that lived in the rock would have died off during the harvesting and transportation process posing a risk to an immature aquarium of rapid ammonia production due to the dead organisms decomposing. To combat this a curing process must be carried out involving leaving the rock to sit in water for up to several weeks to ensure all dead organisms have decomposed and no longer pose a threat to water quality. There are many different types of live rock; each is named after the area. A large amount of live rock comes from the Southern Pacific region, in areas such as Fiji and the Marshall Islands, as well as from the Caribbean; each has its own distinct qualities. For instance, live rock from the Fiji region is porous and large, rock from the Tonga region is dense and elongated. Base rock, or dry rock, is a generic term for aragonite rock that has no organisms growing in or on the rock. Base rock is used as filler rock in the aquarium as it is much cheaper to purchase than live rock.
In time, base rock will become colonized by living organisms. Base rock, mined from inland ancient reefs has become a popular way to keep the aquarium trade going sustainably; this rock is either maricultured and sold as live rock, or can be purchased and grown in the home aquarium. Base rock can be made from artificial rock called aragocrete, a hand made concrete from combining crushed aragonite and Portland cement. After allowing the cement to dry, the pieces are sometimes acid washed to counteract the high pH of the materials, allowed to soak in clean water for one or more months, they tend to be heavier and less attractive when compared to natural base rock. As of August 4, 2008 CITES banned the collection of live rock from Tonga, the Marshall Islands, the Cook Islands; this is due to the over-collecting of rock in these areas. This ban remains in effect as of 2014. About Live Rock and its purpose