|
Microatoll
A microatoll is a circular colony of coral, dead on the top but living around the perimeter. Growth is mainly lateral, as upward growth is limited by exposure to air. Microatolls may be up to in diameter. They are named for their resemblance to island atolls formed during the subsidence of volcanic islands, as originally suggested by Darwin (1842). They act as natural recorders of sea level, which allows the monitoring of sea level changes in response to global warming. They have also been used to quantify and date changes in relative sea level in seismically active areas, and to provide information on changes in sea surface temperature using oxygen isotope values as a proxy. Terminology The term 'microatoll' was first used by Krempf in 1927, although his description lacks a precise definition. Kuenen defined it in 1933 as "a colony of corals" with "a raised rim, more or less completely surrounding a lower, dead surface". This definition has been extended to include similar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
1833 Sumatra Earthquake
The 1833 Sumatra earthquake occurred on November 25 at about 22:00 local time, with an estimated magnitude in the range of 8.8–9.2 . It caused a large tsunami that flooded the southwestern coast of the island. There are no reliable records of the loss of life, with the casualties being described only as 'numerous'. The magnitude of this event has been estimated using records of uplift taken from coral microatolls. Background The island of Sumatra lies on the convergent plate boundary between the Indo-Australian plate and the Eurasian plate. The convergence between these plates is highly oblique near Sumatra, with the displacement being accommodated by near pure dip-slip faulting along the subduction zone, known as the Sunda megathrust, and near pure strike-slip faulting along the Great Sumatran fault. The major slip events on the subduction zone interface are typically of megathrust type. Historically, great or giant megathrust earthquakes have been recorded in 1797 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Coral
Corals are colonial marine invertebrates within the subphylum Anthozoa of the phylum Cnidaria. They typically form compact Colony (biology), colonies of many identical individual polyp (zoology), polyps. Coral species include the important Coral reef, reef builders that inhabit tropical oceans and secrete calcium carbonate to form a hard skeleton. A coral "group" is a colony of very many cloning, genetically identical polyps. Each polyp is a sac-like animal typically only a few millimeters in diameter and a few centimeters in height. A set of tentacles surround a central mouth opening. Each polyp excretes an exoskeleton near the base. Over many generations, the colony thus creates a skeleton characteristic of the species which can measure up to several meters in size. Individual colonies grow by asexual reproduction of polyps. Corals also breed sexually by spawning: polyps of the same species release gametes simultaneously overnight, often around a full moon. Fertilized eggs form ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Porites
''Porites'' is a genus of stony coral; they are small polyp stony (SPS) corals. (Also referred to as finger coral or hump coral) They are characterised by a finger-like morphology. Members of this genus have widely spaced calices, a well-developed wall reticulum and are bilaterally symmetrical. ''Porites'', particularly '' Porites lutea'', often form microatolls. Corals of the genus ''Porites'' also often serve as hosts for Christmas tree worms ('' Spirobranchus giganteus''). Aquarium trade Specimens of ''Porites'' are sometimes available for purchase in the aquarium trade. Due to the strict water quality, lighting and dietary requirements, keeping ''Porites'' in captivity is very difficult. Paleoclimatology ''Porites'' corals have been shown to be accurate and precise recorders of past marine surface conditions. Measurements of the oxygen isotopic composition of the aragonitic skeleton of coral specimens indicate the sea-surface temperature conditions and the oxygen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Heliopora
''Heliopora'' is a genus of cnidarian in the family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ... Helioporidae. The genus consists of reef building corals, and is ancient and highly conserved. The species ''heliopora coerulea'' is also known as "blue coral". Species Currently, the species known to be part of the genus Heliopora are: * '' Heliopora coerulea'' (Pallas, 1766) - blue coral * '' Heliopora fijiensis''† Hoffmeister, 1945 *'' Heliopora hiberniana'' Richards, Yasuda, Kikuchi, Foster, Mitsuyuki, Stat, Suyama & Wilson, 2018 References Octocorallia genera Helioporidae {{Octocorallia-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Isotope
Isotopes are distinct nuclear species (or ''nuclides'') of the same chemical element. They have the same atomic number (number of protons in their Atomic nucleus, nuclei) and position in the periodic table (and hence belong to the same chemical element), but different nucleon numbers (mass numbers) due to different numbers of neutrons in their nuclei. While all isotopes of a given element have similar chemical properties, they have different atomic masses and physical properties. The term isotope is derived from the Greek roots isos (wikt:ἴσος, ἴσος "equal") and topos (wikt:τόπος, τόπος "place"), meaning "the same place"; thus, the meaning behind the name is that different isotopes of a single element occupy the same position on the periodic table. It was coined by Scottish doctor and writer Margaret Todd (doctor), Margaret Todd in a 1913 suggestion to the British chemist Frederick Soddy, who popularized the term. The number of protons within the atomic nuc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Oxygen
Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), group in the periodic table, a highly reactivity (chemistry), reactive nonmetal (chemistry), nonmetal, and a potent oxidizing agent that readily forms oxides with most elements as well as with other chemical compound, compounds. Oxygen is abundance of elements in Earth's crust, the most abundant element in Earth's crust, making up almost half of the Earth's crust in the form of various oxides such as water, carbon dioxide, iron oxides and silicates.Atkins, P.; Jones, L.; Laverman, L. (2016).''Chemical Principles'', 7th edition. Freeman. It is abundance of chemical elements, the third-most abundant element in the universe after hydrogen and helium. At standard temperature and pressure, two oxygen atoms will chemical bond, bind covalent bond, covalently to form dioxygen, a colorless and odorless diatomic gas with the chemical formula ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Earthquake
An earthquakealso called a quake, tremor, or tembloris the shaking of the Earth's surface resulting from a sudden release of energy in the lithosphere that creates seismic waves. Earthquakes can range in intensity, from those so weak they cannot be felt, to those violent enough to propel objects and people into the air, damage critical infrastructure, and wreak destruction across entire cities. The seismic activity of an area is the frequency, type, and size of earthquakes experienced over a particular time. The seismicity at a particular location in the Earth is the average rate of seismic energy release per unit volume. In its most general sense, the word ''earthquake'' is used to describe any seismic event that generates seismic waves. Earthquakes can occur naturally or be induced by human activities, such as mining, fracking, and nuclear weapons testing. The initial point of rupture is called the hypocenter or focus, while the ground level directly above it is the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Fossil
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood and DNA remnants. The totality of fossils is known as the ''fossil record''. Though the fossil record is incomplete, numerous studies have demonstrated that there is enough information available to give a good understanding of the pattern of diversification of life on Earth. In addition, the record can predict and fill gaps such as the discovery of '' Tiktaalik'' in the arctic of Canada. Paleontology includes the study of fossils: their age, method of formation, and evolutionary significance. Specimens are sometimes considered to be fossils if they are over 10,000 years old. The oldest fossils are around 3.48 billion years to 4.1 billion years old. Early edition, published online before prin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Sea Level
Mean sea level (MSL, often shortened to sea level) is an mean, average surface level of one or more among Earth's coastal Body of water, bodies of water from which heights such as elevation may be measured. The global MSL is a type of vertical datuma standardised geodetic datumthat is used, for example, as a chart datum in cartography and Navigation, marine navigation, or, in aviation, as the standard sea level at which atmospheric pressure is measured to Calibration, calibrate altitude and, consequently, aircraft flight levels. A common and relatively straightforward mean sea-level standard is instead a long-term average of tide gauge readings at a particular reference location. The term ''above sea level'' generally refers to the height above mean sea level (AMSL). The term APSL means above present sea level, comparing sea levels in the past with the level today. Earth's radius at sea level is 6,378.137 km (3,963.191 mi) at the equator. It is 6,356.752 km (3,94 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Goniastrea
''Goniastrea'' is a genus (biology), genus of Scleractinia, stony corals in the family (biology), family Merulinidae. Species belonging to the genus ''Goniastrea'' forms massive colonies, usually spherical or elongate, with well developed paliform lobes. Polyps can be seen only at night. Species The following species are currently recognized by the World Register of Marine Species : * ''Goniastrea columella'' Crossland, 1948 * ''Goniastrea edwardsi'' Chevalier, 1971 * ''Goniastrea favulus'' (Dana, 1846) * ''Goniastrea minuta'' Veron, 2002 * ''Goniastrea pectinata'' (Ehrenberg, 1834) * ''Goniastrea ramosa'' Veron, 2002 * ''Goniastrea retiformis'' (Lamarck, 1816) * ''Goniastrea stelligera'' (Dana, 1846) * ''Goniastrea thecata'' Veron, DeVantier & Turak, 2002 References Merulinidae Scleractinia genera {{scleractinia-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
