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Aliwal Shoal
The Aliwal Shoal is a rocky reef which is the remains of an ancient sand dune approximately off the coast of KwaZulu-Natal, South Africa. The reef is inhabited by many kinds of hard and soft corals and other marine invertebrates, and a variety of tropical and subtropical fish species. Aliwal Shoal was named after the near-sinking in 1849 of the three-masted vessel ''Aliwal'', captained by James Anderson. There are two wrecks near the reef that are popular recreational dive sites. The Norwegian bulk carrier MV ''Produce'' sank in 1974, and SS ''Nebo'' sank in 1884. Aliwal Shoal has diverse marine life, including large predators, and is popular as a recreational scuba diving destination. The Shoal is known especially for its abundance of Grey nurse sharks (known locally as ragged tooth sharks or "raggies") between July and November when the sharks congregate there to mate. Morphology Aliwal shoal is part of a large offshore reef complex. The narrow ridge parallel to the coastline a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arch At Cathedral DSC05788a
An arch is a vertical curved structure that spans an elevated space and may or may not support the weight above it, or in case of a horizontal arch like an arch dam, the hydrostatic pressure against it. Arches may be synonymous with vaults, but a vault may be distinguished as a continuous arch forming a roof. Arches appeared as early as the 2nd millennium BC in Mesopotamian brick architecture, and their systematic use started with the ancient Romans, who were the first to apply the technique to a wide range of structures. Basic concepts An arch is a pure compression form. It can span a large area by resolving forces into compressive stresses, and thereby eliminating tensile stresses. This is sometimes denominated "arch action". As the forces in the arch are transferred to its base, the arch pushes outward at its base, denominated "thrust". As the rise, i. e. height, of the arch decreases the outward thrust increases. In order to preserve arch action and prevent collapse ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypnea
''Hypnea'' is a genus of red algae, and a well known carrageenophyte (plant producing polysaccharide carrageenan). Taxonomy and Nomenclature ''Hypnea'' is a genus of red seaweed under class Florideophyceae, order Gigartinales, and family Cystocloniaceae. There are 99 species listed on Algaebase with 78 being accepted taxonomically. The genus was originally classified under family Hypneaceae, which was considered distinct from Cystoclonoiaceae on the basis of differences in their carposporophyte structure, and the shape of the thalli and cortical cells. Differences in carrageenan chemistry, with Hypneaceae species producing kappa-carrageenan and Cystocloniaceae producing lambda-carrageenan, was another reason for their distinction. However, these criteria were questioned and molecular analysis later showed that the two families had similar vegetative and reproductive characters. Furthermore, it was proven that lambda-carrageenan and kappa-carrageen coexist within the Gigartinal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cliona Orientalis
''Cliona orientalis'' is a species of demosponge in the family Clionaidae. It occurs in the Indo-Pacific region and is a bioeroding species, with various specialisations for living on and inside calcareous substrates such as massive corals and molluscs. Distribution and habitat ''C. orientalis'' is native to the tropical Indo-Pacific region. Its range extends from East Africa and Madagascar, through India and the Maldives, to northern Australia, the Philippines, and many island groups in the Western Pacific Ocean. Its depth range is down to about . Ecology Like other demosponges, ''C. orientalis'' is a filter feeder. Water is drawn in through fine pores, the nutritious particles are filtered out, and the water exits the sponge through the oscula. In addition, this sponge is able to extract nutrition from dissolved sugars in the water. It is a hermaphrodite; sperm are liberated into the water column and drawn into another individual via the water current, fertilisation being i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dragmacidon Sanguineum
''Dragmacidon'' is a genus of sponges in the family Axinellidae, first described in 1917 by E.F.Hallman . List of species *'' Dragmacidon agariciforme'' (Dendy, 1905) *'' Dragmacidon alvarezae'' Zea & Pulido, 2016 *'' Dragmacidon australe'' (Bergquist, 1970) *'' Dragmacidon clathriforme'' (Lendenfeld, 1888) *'' Dragmacidon coccineum'' (Keller, 1891) *'' Dragmacidon condylia'' (Hooper & Lévi, 1993) *'' Dragmacidon debitusae'' (Hooper & Lévi, 1993) *'' Dragmacidon decipiens'' (Wiedenmayer, 1989) *'' Dragmacidon durissimum'' (Dendy, 1905) *'' Dragmacidon egregium'' (Ridley, 1881) *'' Dragmacidon fibrosum'' (Ridley & Dendy, 1886) *'' Dragmacidon grayi'' (Wells, Wells & Gray., 1960) *'' Dragmacidon incrustans'' (Whitelegge, 1897) *'' Dragmacidon kishinense'' Austin, Ott, Reiswig, Romagosa & McDaniel, 2013 *'' Dragmacidon lunaecharta'' (Ridley & Dendy, 1886) *'' Dragmacidon mexicanum'' (de Laubenfels, 1935) *'' Dragmacidon mutans'' (Sarà, 1978) *'' Dragmacidon ophisclera'' de Lau ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Porifera
Sponges, the members of the phylum Porifera (; meaning 'pore bearer'), are a basal animal clade as a sister of the diploblasts. They are multicellular organisms that have bodies full of pores and channels allowing water to circulate through them, consisting of jelly-like mesohyl sandwiched between two thin layers of cells. Sponges have unspecialized cells that can transform into other types and that often migrate between the main cell layers and the mesohyl in the process. Sponges do not have nervous, digestive or circulatory systems. Instead, most rely on maintaining a constant water flow through their bodies to obtain food and oxygen and to remove wastes. Sponges were first to branch off the evolutionary tree from the last common ancestor of all animals, making them the sister group of all other animals. Etymology The term ''sponge'' derives from the Ancient Greek word ( 'sponge'). Overview Sponges are similar to other animals in that they are multicellular, hete ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zonaria Subarticulata
Zonaria is a melodic death metal band from Umeå, Sweden, formerly known as Seal Precious. The band is currently signed to Century Media Records. Background Formed in 2001 by Simon Berglund, Christoffer Vikström, and Mikael Hammarberg, the band originally went under the name Seal Precious. Initially the band's style was power metal, with clean vocals. Several line-up changes prevented the band from recording, but after 2003, with the addition of second guitarist, Emil Nyström, and the band's name changed to Zonaria, they spent two years playing gigs in and around Umeå before recording and releasing, in 2005, what would be '' Evolution Overdose''. New material and touring In the spring of 2006, Zonaria recorded the CD single " Rendered in Vain" (and later shot a video for it). After that, Zonaria toured outside of Sweden, opening for Finnish black metal band Impaled Nazarene on a European tour. In October, Zonaria announced they had signed a record deal with Swedmetal Reco ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stypopodium Multipartitum
''Stypopodium'' is a genus of thalloid brown alga in the family Dictyotaceae. Members of the genus are found in shallow tropical and subtropical seas around Africa, Pakistan, India, Japan, Indonesia, Australia, Micronesia, the Caribbean, Venezuela, and Brazil.''Stypopodium'' AlgaeBase. Retrieved 2012-06-29. Characteristics The are usually erect but sometimes prostrate, growing to a length of about . They are attached to the substrate by a al holdfast and often fo ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lobophora Variegata
''Lobophora variegata'' is a species of small thalloid brown alga which grows intertidally or in shallow water in tropical and warm temperate seas. It has three basic forms, being sometimes ruffled, sometimes reclining and sometimes encrusting, and each form is typically found in a different habitat. This seaweed occurs worldwide. It is the type species of the genus '' Lobophora'', the type locality being the Antilles in the West Indies. Description ''Lobophora variegata'' has three different morphological forms; an erect ruffled form, a decumbent or reclining form which grows flattened against the substrate and an encrusting form. Each of these forms may dominate its habitat. This seaweed is generally greenish-brown or pale brown. The sporangial sori are scattered across both surfaces of the thalli (fronds). The ruffled form grows in ball-like clumps of wavy fronds as a result of the continued growth of the lateral blades. It is most often found in sandy areas and among tu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dictyota Dichotoma
''Dictyota dichotoma'' is a species of Brown algae found in the temperate western and eastern Atlantic Ocean, the Mediterranean Sea, the Black Sea, the Red Sea and the western Indian Ocean. Description The thallus of ''Dictyota dichotoma'' grows in tufts and is a yellowish-brown or greenish colour, with a faint bluish iridescence when underwater. It forms membranous, flattened, dichotomously-branching fronds up to long and wide. These have a reticulated (net-like) structure and no midrib. The tufts are semi-erect and have little or no stalk; they are anchored to the seabed by rhizoids, filamentous outgrowths that can absorb nutrients from their surroundings. The thallus branches are strap-like, the branches being equal in length and having rounded ends. Clusters of spores develop in round or oval sori under the surface of the thallus, finally bursting through. Distribution and habitat ''Dictyota dichotoma'' has a wide range, being found in the western Atlantic Ocean and the ea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phaeophyta
Brown algae (singular: alga), comprising the class Phaeophyceae, are a large group of multicellular algae, including many seaweeds located in colder waters within the Northern Hemisphere. Brown algae are the major seaweeds of the temperate and polar regions. They are dominant on rocky shores throughout cooler areas of the world. Most brown algae live in marine environments, where they play an important role both as food and as a potential habitat. For instance, ''Macrocystis'', a kelp of the order Laminariales, may reach in length and forms prominent underwater kelp forests. Kelp forests like these contain a high level of biodiversity. Another example is ''Sargassum'', which creates unique floating mats of seaweed in the tropical waters of the Sargasso Sea that serve as the habitats for many species. Many brown algae, such as members of the order Fucales, commonly grow along rocky seashores. Some members of the class, such as kelps, are used by humans as food. Between 1,500 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peyssonnelia Capensis
''Peyssonnelia'' is a genus of thalloid red alga, named after naturalist Jean-André Peyssonnel (1694–1759) It includes the algae commonly known as rumoi-iwanokawa, mayoi-iwanokawa and akase-iwanokawa. Specimens can reach around 20 cm in size. ''Peyssonnelia'' produces tetraspores. Taxonomy and Nomenclature ''Peyssonnelia'' belongs to class Florideophyceae, of the order Peyssonneliales and Family Peyssonneliaceae. There are 89 currently recognized species as of 2021. Its lectotype is ''Peyssonnelia squamaria''. The genus is the largest in the Peyssonneliaceae. Segregate Genera The genera ''Cruoriella'' and ''Cruoriopsis'' are sometimes considered to be part of ''Peyssonnelia'', but a 2007 dissertation by Krayesky separates them. Morphology The genus is calcareous and is characterized by crustose, prostrate thalli attached to the substrate by uni- or multicellular rhizoids. Thalli may be partially or fully calcified, with calcium carbonate deposited as aragonite ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
