1.
The Coral Island
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The Coral Island, A Tale of the Pacific Ocean is a novel written by Scottish author R. M. Ballantyne. Among the novels themes are the civilising effect of Christianity, 19th-century British imperialism in the South Pacific. In the early 20th century, the novel was considered a classic for primary children in the UK. Born in Edinburgh in 1825, and raised there, Ballantyne was the ninth of ten children, tutored by his mother and sisters, his only formal education was a brief period at Edinburgh Academy in 1835–37. At the age of 16 he travelled to Canada, where he spent five years working for the Hudsons Bay Company and he returned to Scotland in 1847 and for some years worked for the publisher Messrs Constable, first as a clerk and then as a partner in the business. Ballantyne wrote The Coral Island while staying in a house on the Burntisland seafront opposite Edinburgh on the Firth of Forth in Fife, according to Ballantyne biographer Eric Quayle he borrowed extensively from an 1852 novel by the American author James F. Bowman, The Island Home. Edmond describes the novel as a cocktail of other writing about the Pacific. The Coral Island is Ballantynes second novel, and has never been out of print and he was an exceedingly prolific author who wrote more than 100 books in his 40-year career. The first edition of The Coral Island was published by T and he wrote bitterly to Nelsons in 1893 about the copyrights they held on his books while he had earned nothing, for thirty-eight years reaped the whole profits. The Coral Island – still considered a classic – was republished by Penguin Books in 1995, published during the first golden age of childrens fiction, The Coral Island began a trend in boys fiction by using boys as the main characters, a device now commonplace in the genre. According to literary critic Frank Kermode, The Coral Island could be used as a document in the history of ideas, a scientific and social background for the novel is found in Darwinism, of the natural and the social kind. For instance, published a year before Origin of Species, Charles Darwins 1842 The Structure, Ballantyne had been reading books by Darwin and by his rival Alfred Russel Wallace, in later publications he also acknowledged the naturalist Henry Ogg Forbes. The story is written as a first person narrative from the perspective of 15-year-old Ralph Rover, Ralph tells the story retrospectively, looking back on his boyhood adventure, I was a boy when I went through the wonderful adventures herein set down. The account starts briskly, only four pages are devoted to Ralphs early life and he and his two companions – 18-year-old Jack Martin and 13-year-old Peterkin Gay – are the sole survivors of the shipwreck. The narrative is in two parts, the first describes how the boys feed themselves, what they drink, the clothing and shelter they fashion, and how they cope with having to rely on their own resources. The second half of the novel is more action-packed, featuring conflicts with pirates, fruit, fish and wild pigs provide plentiful food, and at first the boys life on the island is idyllic. They build a shelter and construct a boat using their only possessions, a broken telescope, an iron-bound oar. Their first contact with other humans comes after several months when they observe two large outrigger canoes in the distance, one pursued by the other
2.
Island
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An island or isle is any piece of sub-continental land that is surrounded by water. Very small islands such as emergent land features on atolls can be called islets, skerries, an island in a river or a lake island may be called an eyot or ait, and a small island off the coast may be called a holm. A grouping of geographically or geologically related islands is called an archipelago, an island may be described as such, despite the presence of an artificial land bridge. Example, Singapore and its causeway, or the various Dutch delta islands, there are two main types of islands in the sea, continental and oceanic. The word island derives from Middle English iland, from Old English igland, Old English ieg is actually a cognate of Swedish ö and German Aue, and related to Latin aqua. There is a difference between islands and continents in terms of geology, continents sit on continental lithosphere which is part of tectonic plates floating high on Earths mantle. Oceanic crust is also part of tectonic plates, but it is denser than continental lithosphere, Islands are either extensions of the oceanic crust or geologically they are part of some continent sitting on continental lithosphere. This holds true for Australia, which sits on its own continental lithosphere, continental islands are bodies of land that lie on the continental shelf of a continent. A special type of island is the microcontinental island, which is created when a continent is rifted. Examples are Madagascar and Socotra off Africa, the Kerguelen Islands, New Caledonia, New Zealand, another subtype is an island or bar formed by deposition of tiny rocks where water current loses some of its carrying capacity. While some are transitory and may disappear if the volume or speed of the current changes, others are stable, oceanic islands are islands that do not sit on continental shelves. The vast majority are volcanic in origin, such as Saint Helena in the South Atlantic Ocean, the few oceanic islands that are not volcanic are tectonic in origin and arise where plate movements have lifted up the ocean floor above the surface. Examples are Saint Peter and Paul Rocks in the Atlantic Ocean, one type of volcanic oceanic island is found in a volcanic island arc. These islands arise from volcanoes where the subduction of one plate under another is occurring, examples are the Aleutian Islands, the Mariana Islands, and most of Tonga in the Pacific Ocean. The only examples in the Atlantic Ocean are some of the Lesser Antilles, another type of volcanic oceanic island occurs where an oceanic rift reaches the surface. There are two examples, Iceland, which is the second largest volcanic island, and Jan Mayen. A third type of oceanic island is formed over volcanic hotspots. A hotspot is more or less stationary relative to the tectonic plate above it
3.
Coral
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Corals are marine invertebrates in the class Anthozoa of phylum Cnidaria. They typically live in colonies of many identical individual polyps. The group includes the important reef builders that inhabit tropical oceans, a coral group is a colony of myriad genetically identical polyps. Each polyp is an animal typically only a few millimeters in diameter. A set of tentacles surround a central mouth opening, an exoskeleton is excreted near the base. Over many generations, the colony creates a large skeleton that is characteristic of the species. Individual heads grow by reproduction of polyps. Corals also breed sexually by spawning, polyps of the same species release gametes simultaneously over a period of one to several nights around a full moon and these are commonly known as zooxanthellae and the corals that contain them are zooxanthellate corals. Such corals require sunlight and grow in clear, shallow water, other corals do not rely on zooxanthellae and can live in much deeper water, with the cold-water genus Lophelia surviving as deep as 3,000 metres. Some have been found on the Darwin Mounds, north-west of Cape Wrath, Corals have also been found as far north as off the coast of Washington State and the Aleutian Islands. In his Scala Naturae, Aristotle classified corals as zoophyta, animals that had characteristics of plants and were therefore hypothetically in between animals and plants, the Persian polymath Al-Biruni classified sponges and corals as animals, arguing that they respond to touch. The phylogeny of Anthozoans is not clearly understood and a number of different models have been proposed, within the Hexacorallia, the sea anemones, coral anemones and stony corals may constitute a monophyletic grouping united by their eight-fold symmetry and cnidocyte trait. The Octocorallia appears to be monophyletic, and primitive members of this group may have been stolonate, the cladogram presented here comes from a 2014 study by Stampar et al. which was based on the divergence of mitochondrial DNA within the group and on nuclear markers. Corals are classified in the class Anthozoa of the phylum Cnidaria and they are divided into three subclasses, Hexacorallia, Octocorallia, and Ceriantharia. The Hexacorallia include the stony corals, the sea anemones and the zoanthids and these groups have polyps that generally have 6-fold symmetry. The Octocorallia include blue coral, soft corals, sea pens and these groups have polyps with 8-fold symmetry, each polyp having eight tentacles and eight mesenteries. Fire corals are not true corals, being in the order Anthomedusa of the class Hydrozoa, Corals are sessile animals in the class Anthozoa and differ from most other cnidarians in not having a medusa stage in their life cycle. The body unit of the animal is a polyp, most corals are colonial, the initial polyp budding to produce another and the colony gradually developing from this small start
4.
Detritus
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In biology, detritus is dead particulate organic material. It typically includes the bodies or fragments of organisms as well as fecal material. Detritus is typically colonized by communities of microorganisms which act to decompose the material, in terrestrial ecosystems, it is encountered as leaf litter and other organic matter intermixed with soil, which is referred to as humus. Detritus of aquatic ecosystems is organic material suspended in water and piles up on seabed floors which is referred to as marine snow. Dead plants or animals, material derived from animal tissues gradually lose their form, decomposition, the process through which organic matter is decomposed, takes place in many stages. Materials like proteins, lipids and sugars with low weight are rapidly consumed and absorbed by micro-organisms and organisms that feed on dead matter. Other compounds, such as complex carbohydrates are broken down more slowly, the various micro-organisms involved in the decomposition break down the organic materials in order to gain the resources they require for their own survival and proliferation. Accordingly, at the time that the materials of plants and animals are being broken down. In ecosystems on land, detritus is deposited on the surface of the ground, in aquatic ecosystems, most detritus is suspended in water, and gradually settles. In particular, many different types of material are collected together by currents, much detritus is used as a source of nutrition for animals. In particular, many bottom feeding animals living in mud flats feed in this way, however, there are many micro-organisms which multiply in natural environments. A characteristic type of food chain called the cycle takes place involving detritus feeders, detritus. For example, mud flats are inhabited by many univalves which are detritus feeders, what is left behind by the detritivores is then further broken down and recycled by decomposers, such as bacteria and fungi. In ecosystems on land, far more material is broken down as dead material passing through the detritus chain than is broken down by being eaten by animals in a living state. In both land and aquatic ecosystems, the role played by detritus is too large to ignore, in contrast to land ecosystems, dead materials and excreta in aquatic ecosystems do not settle immediately, and the finer the particles involved are, the longer they tend to take. Detritus occurs in a variety of habitats including forest, chaparral. In forests the detritus is typically dominated by leaf, twig and this plant litter provides important cover for seedling protection as well as cover for a variety of arthropods, reptiles and amphibians. Some insect larvae feed on the detritus, there is an extremely large number of detritus feeders in water
5.
Coral reef
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Coral reefs are diverse underwater ecosystems held together by calcium carbonate structures secreted by corals. Coral reefs are built by colonies of tiny animals found in waters that contain few nutrients. Most coral reefs are built from stony corals, which in turn consist of polyps that cluster in groups, the polyps belong to a group of animals known as Cnidaria, which also includes sea anemones and jellyfish. Unlike sea anemones, corals secrete hard carbonate exoskeletons which support, most reefs grow best in warm, shallow, clear, sunny and agitated waters. Often called rainforests of the sea, shallow coral reefs form some of the most diverse ecosystems on Earth, paradoxically, coral reefs flourish even though they are surrounded by ocean waters that provide few nutrients. They are most commonly found at depths in tropical waters. Coral reefs deliver ecosystem services to tourism, fisheries and shoreline protection, the annual global economic value of coral reefs is estimated between US$29. 8-375 billion. However, coral reefs are fragile ecosystems, partly because they are sensitive to water temperature. Most of the coral reefs we can see today were formed after the last glacial period when melting ice caused the sea level to rise and this means that most modern coral reefs are less than 10,000 years old. As communities established themselves on the shelves, the reefs grew upwards, Reefs that rose too slowly could become drowned reefs. They are covered by so much water there was insufficient light. Coral reefs are found in the sea away from continental shelves, around oceanic islands. The vast majority of islands are volcanic in origin. The few exceptions have tectonic origins where plate movements have lifted the deep ocean floor on the surface. In 1842 in his first monograph, The Structure and Distribution of Coral Reefs, Charles Darwin set out his theory of the formation of atoll reefs and he theorized uplift and subsidence of the Earths crust under the oceans formed the atolls. Darwin’s theory sets out a sequence of three stages in atoll formation and it starts with a fringing reef forming around an extinct volcanic island as the island and ocean floor subsides. As the subsidence continues, the reef becomes a barrier reef. Darwin predicted that underneath each lagoon would be a bed rock base, where the level of the underlying earth allows, the corals grow around the coast to form what he called fringing reefs, and can eventually grow out from the shore to become a barrier reef
6.
Limestone
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Limestone is a sedimentary rock, composed mainly of skeletal fragments of marine organisms such as coral, forams and molluscs. Its major materials are the minerals calcite and aragonite, which are different crystal forms of calcium carbonate, about 10% of sedimentary rocks are limestones. The solubility of limestone in water and weak acid solutions leads to karst landscapes, most cave systems are through limestone bedrock. The first geologist to distinguish limestone from dolomite was Belsazar Hacquet in 1778, like most other sedimentary rocks, most limestone is composed of grains. Most grains in limestone are skeletal fragments of organisms such as coral or foraminifera. Other carbonate grains comprising limestones are ooids, peloids, intraclasts and these organisms secrete shells made of aragonite or calcite, and leave these shells behind when they die. Limestone often contains variable amounts of silica in the form of chert or siliceous skeletal fragment, some limestones do not consist of grains at all, and are formed completely by the chemical precipitation of calcite or aragonite, i. e. travertine. Secondary calcite may be deposited by supersaturated meteoric waters and this produces speleothems, such as stalagmites and stalactites. Another form taken by calcite is oolitic limestone, which can be recognized by its granular appearance, the primary source of the calcite in limestone is most commonly marine organisms. Some of these organisms can construct mounds of rock known as reefs, below about 3,000 meters, water pressure and temperature conditions cause the dissolution of calcite to increase nonlinearly, so limestone typically does not form in deeper waters. Limestones may also form in lacustrine and evaporite depositional environments, calcite can be dissolved or precipitated by groundwater, depending on several factors, including the water temperature, pH, and dissolved ion concentrations. Calcite exhibits a characteristic called retrograde solubility, in which it becomes less soluble in water as the temperature increases. Impurities will cause limestones to exhibit different colors, especially with weathered surfaces, Limestone may be crystalline, clastic, granular, or massive, depending on the method of formation. Crystals of calcite, quartz, dolomite or barite may line small cavities in the rock, when conditions are right for precipitation, calcite forms mineral coatings that cement the existing rock grains together, or it can fill fractures. Travertine is a banded, compact variety of limestone formed along streams, particularly there are waterfalls. Calcium carbonate is deposited where evaporation of the leaves a solution supersaturated with the chemical constituents of calcite. Tufa, a porous or cellular variety of travertine, is found near waterfalls, coquina is a poorly consolidated limestone composed of pieces of coral or shells. During regional metamorphism that occurs during the building process, limestone recrystallizes into marble
7.
Biodiversity
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Biodiversity, a contraction of biological diversity, generally refers to the variety and variability of life on Earth. One of the most widely used definitions defines it in terms of the variability within species and it is a measure of the variety of organisms present in different ecosystems. This can refer to genetic variation, ecosystem variation, or species variation within an area, biome, terrestrial biodiversity tends to be greater near the equator, which seems to be the result of the warm climate and high primary productivity. Biodiversity is not distributed evenly on Earth, and is richest in the tropics and these tropical forest ecosystems cover less than 10 per cent of earths surface, and contain about 90 percent of the worlds species. Marine biodiversity tends to be highest along coasts in the Western Pacific, there are latitudinal gradients in species diversity. Biodiversity generally tends to cluster in hotspots, and has been increasing through time, the number and variety of plants, animals and other organisms that exist is known as biodiversity. It is a component of nature and it ensures the survival of human species by providing food, fuel, shelter, medicines. The richness of biodiversity depends on the conditions and area of the region. All species of plants taken together are known as flora and about 300,000 species of plants are known to date, all species of animals taken together are known as fauna which includes birds, mammals, fish, reptiles, insects, crustaceans, molluscs, etc. Rapid environmental changes typically cause mass extinctions, more than 99 percent of all species, amounting to over five billion species, that ever lived on Earth are estimated to be extinct. Estimates on the number of Earths current species range from 10 million to 14 million, of which about 1.2 million have been documented and over 86 percent have not yet been described. More recently, in May 2016, scientists reported that 1 trillion species are estimated to be on Earth currently with only one-thousandth of one percent described, the total amount of related DNA base pairs on Earth is estimated at 5.0 x 1037 and weighs 50 billion tonnes. In comparison, the mass of the biosphere has been estimated to be as much as 4 TtC. In July 2016, scientists reported identifying a set of 355 genes from the Last Universal Common Ancestor of all living on Earth. The age of the Earth is about 4.54 billion years old, there are microbial mat fossils found in 3.48 billion-year-old sandstone discovered in Western Australia. Other early physical evidence of a substance is graphite in 3.7 billion-year-old meta-sedimentary rocks discovered in Western Greenland. More recently, in 2015, remains of life were found in 4.1 billion-year-old rocks in Western Australia. According to one of the researchers, If life arose relatively quickly on Earth, then it could be common in the universe
8.
Calcareous
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Calcareous is an adjective meaning mostly or partly composed of calcium carbonate, in other words, containing lime or being chalky. The term is used in a variety of scientific disciplines. The term also applies to the calcium carbonate tests of often more or less microscopic Foraminifera, note that not all tests are calcareous, diatoms and radiolaria have siliceous tests. The molluscs are calcareous, as are calcareous sponges, that have spicules which are made of calcium carbonate, calcareous grassland is a form of grassland characteristic of soils containing much calcium carbonate from underlying chalk or limestone rock. Species of algae such as the green-segmented genus Halimeda are calcareous, the term is used in pathology, for example in calcareous conjunctivitis, and when referring to calcareous metastasis or calcareous deposits, which may both be removed surgically. The term calcareous can be applied to a sediment, sedimentary rock, or soil type which is formed from, or contains a proportion of. Calcareous sediments are deposited in shallow water near land, since the carbonate is precipitated by marine organisms that need land-derived nutrients. Generally speaking, the farther from land sediments fall, the less calcareous they are, some areas can have interbedded calcareous sediments due to storms, or changes in ocean currents. Calcareous ooze is a form of calcium derived from planktonic organisms that accumulates on the sea floor. This can only occur if the ocean is shallower than the carbonate compensation depth, below this depth, calcium carbonate begins to dissolve in the ocean, and only non-calcareous sediments are stable, such as siliceous ooze or pelagic red clay. Calcareous soils are alkaline, in other words they have a high pH. This is because of the very weak acidity of carbonic acid, note that this is not the only reason for a high soil pH
9.
Hotspot (geology)
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In geology, the places known as hotspots or hot spots are volcanic regions thought to be fed by underlying mantle that is anomalously hot compared with the surrounding mantle. They may be on, near to, or far from plate boundaries. Currently, there are two hypotheses that attempt to explain their origins, one suggests that hotspots are due to mantle plumes that rise as thermal diapirs from the core–mantle boundary. The other hypothesis is that lithospheric extension permits the passive rising of melt from shallow depths and this hypothesis considers the term hotspot to be a misnomer, asserting that the mantle source beneath them is, in fact, not anomalously hot at all. Well known examples include Hawaii, Iceland and Yellowstone and it was later postulated that hotspots are fed by narrow streams of hot mantle rising from the Earths core–mantle boundary in a structure called a mantle plume. Whether or not such mantle plumes exist is currently the subject of a controversy in Earth science. Estimates for the number of hotspots postulated to be fed by mantle plumes has ranged from about 20 to several thousands, over the years, Hawaii, Réunion, Yellowstone, Galápagos, and Iceland are some of the currently most active volcanic regions to which the hypothesis is applied. As a result, they are less explosive than subduction zone volcanoes, where hotspots occur in continental regions, basaltic magma rises through the continental crust, which melts to form rhyolites. These rhyolites can form violent eruptions, for example, the Yellowstone Caldera was formed by some of the most powerful volcanic explosions in geologic history. However, when the rhyolite is completely erupted, it may be followed by eruptions of basaltic magma rising through the same lithospheric fissures, the hotspot hypothesis is now closely linked to the mantle plume hypothesis. Hotspot volcanoes are considered to have a different origin from island arc volcanoes. The latter form over subduction zones, at converging plate boundaries, when one oceanic plate meets another, the denser plate is forced downward into a deep ocean trench. This plate, as it is subducted, releases water into the base of the plate. It is this that fuels a chain of volcanoes, such as the Aleutian Islands, the joint mantle plume/hotspot hypothesis envisages the feeder structures to be fixed relative to one another, with the continents and seafloor drifting overhead. The hypothesis thus predicts that time-progressive chains of volcanoes are developed on the surface, examples are Yellowstone, which lies at the end of a chain of extinct calderas, which become progressively older to the west. Another example is the Hawaiian archipelago, where islands become progressively older, boschi, L. Becker, T. W. Steinberger, B. Mantle plumes, Dynamic models and seismic images, break-up spots, Could the Pacific open as a consequence of plate kinematics. Towards A Better Understanding Of Hot Spot Volcanism, formation of Hotspots Raising Hot Spots Large Igneous Provinces Maria Antretter, PhD Thesis, Moving hotspots – Evidence from paleomagnetism and modeling Do Plumes Exist
