|
Phytodetritus
In oceanography, phytodetritus is the organic particulate matter resulting from phytoplankton and other organic material in surface waters falling to the seabed. This process takes place almost continuously as a "marine snow" of descending particles, falling at the rate of about per day. Under certain conditions, phytoplankton may aggregate and fall rapidly through the water column to arrive little changed on the seabed. These fluxes sometimes occur seasonally or periodically, are sometimes associated with algal blooms and may constitute the greater part of descending organic matter. If the amount is greater than the benthic detritivores can process, the phytodetritus forms a fluffy layer on the surface of the sediment. It accumulates in many shallow and deep water locations throughout the world. Phytodetritus varies in colour and appearance and may be greenish, brown or grey, flocculent or gelatinous. It includes the microscopic remains of diatoms, dinoflagellates, dictyochales, c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Foraminifera
Foraminifera ( ; Latin for "hole bearers"; informally called "forams") are unicellular organism, single-celled organisms, members of a phylum or class (biology), class of Rhizarian protists characterized by streaming granular Ectoplasm (cell biology), ectoplasm for catching food and other uses; and commonly an external shell (called a "Test (biology), test") of diverse forms and materials. Tests of chitin (found in some simple genera, and ''Textularia'' in particular) are believed to be the most primitive type. Most foraminifera are marine, the majority of which live on or within the seafloor sediment (i.e., are benthos, benthic, with different sized species playing a role within the macrobenthos, meiobenthos, and Benthos, microbenthos), while a smaller number float in the water column at various depths (i.e., are planktonic), which belong to the suborder Globigerinina. Fewer are known from freshwater or brackish conditions, and some very few (nonaquatic) soil species have been id ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marine Snow
In the deep ocean, marine snow (also known as "ocean dandruff") is a continuous shower of mostly organic detritus falling from the upper layers of the water column. It is a significant means of exporting energy from the light-rich photic zone to the aphotic zone below, which is referred to as the ''biological pump''. Export production is the amount of organic matter produced in the ocean by primary production that is not recycled (remineralisation, remineralised) before it sinks into the aphotic zone. Because of the role of export production in the ocean's biological pump, it is typically measured in units of carbon (e.g. milligram, mg C square metre, m−2 day, d−1). The term was coined by explorer William Beebe as observed from his bathysphere. As the origin of marine snow lies in activities within the productive photic zone, the prevalence of marine snow changes with seasonal fluctuations in photosynthesis, photosynthetic activity and ocean currents. Marine snow can be an impo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oceanography
Oceanography (), also known as oceanology, sea science, ocean science, and marine science, is the scientific study of the ocean, including its physics, chemistry, biology, and geology. It is an Earth science, which covers a wide range of topics, including ocean currents, waves, and geophysical fluid dynamics; fluxes of various chemical substances and physical properties within the ocean and across its boundaries; ecosystem dynamics; and plate tectonics and seabed geology. Oceanographers draw upon a wide range of disciplines to deepen their understanding of the world’s oceans, incorporating insights from astronomy, biology, chemistry, geography, geology, hydrology, meteorology and physics. History Early history Humans first acquired knowledge of the waves and currents of the seas and oceans in pre-historic times. Observations on tides were recorded by Aristotle and Strabo in 384–322 BC. Early exploration of the oceans was primarily for cartography and mainly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cadaver
A cadaver, often known as a corpse, is a Death, dead human body. Cadavers are used by medical students, physicians and other scientists to study anatomy, identify disease sites, determine causes of death, and provide tissue (biology), tissue to repair a defect in a living human being. Students in medical school study and dissect cadavers as a part of their education. Others who study cadavers include archaeologists and arts students. In addition, a cadaver may be used in the development and evaluation of surgical instruments. The term ''cadaver'' is used in courts of law (and, to a lesser extent, also by media outlets such as newspapers) to refer to a dead body, as well as by recovery teams searching for bodies in natural disasters. The word comes from the Latin word ''cadere'' ("to fall"). Related terms include ''cadaverous'' (resembling a cadaver) and ''cadaveric spasm'' (a muscle spasm causing a dead body to twitch or jerk). A cadaver graft (also called “postmortem graft”) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Globigerina
''Globigerina'' () is a genus of planktonic Foraminifera, in the order of Rotaliida.Globigerina World Foraminifera Database, accessed 3 December 2018 It has populated the world's oceans since the Middle Jurassic. ''Globigerina'' ooze Vast areas of the ocean floor are covered with ''Globigerina'' Pelagic sediments, ooze, dominated by the foraminiferous shells of ''Globigerina'' and other Globigerinina. The name was originally applied to mud collected from the bottom of the Atlantic Ocean when planning the location of the first transatlantic telegraph cables and it was mainly composed of the shells of ''Globigerina bulloides''.Description ''Globigerina'' is a marine microorganism characterized by its spherical, coiled shell known as a test (biology), test. The t ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plankton
Plankton are the diverse collection of organisms that drift in Hydrosphere, water (or atmosphere, air) but are unable to actively propel themselves against ocean current, currents (or wind). The individual organisms constituting plankton are called plankters. In the ocean, they provide a crucial source of food to many small and large aquatic organisms, such as bivalves, fish, and baleen whales. Marine plankton include bacteria, archaea, algae, protozoa, microscopic fungi, and drifting or floating animals that inhabit the saltwater of oceans and the brackish waters of estuaries. fresh water, Freshwater plankton are similar to marine plankton, but are found in lakes and rivers. Mostly, plankton just drift where currents take them, though some, like jellyfish, swim slowly but not fast enough to generally overcome the influence of currents. Although plankton are usually thought of as inhabiting water, there are also airborne versions that live part of their lives drifting in the at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Picoplankton
Picoplankton is the fraction of plankton composed by cell (biology), cells between 0.2 and 2 μm that can be either prokaryotic and eukaryotic phototrophs and heterotrophs: * photosynthetic * heterotrophic They are prevalent amongst microbial plankton communities of both freshwater and marine ecosystems. They have an important role in making up a significant portion of the total biomass of phytoplankton communities. Classification In general, plankton can be categorized on the basis of physiological, taxonomic, or dimensional characteristics. Subsequently, a generic classification of a plankton includes: * Bacterioplankton * Phytoplankton * Zooplankton However, there is a simpler scheme that categorizes plankton based on a logarithmic size scale: * Macroplankton (200–2000 μm) * Micro-plankton (20–200 μm) * Nanoplankton (2–20 μm) This was even further expanded to include picoplankton (0.2–2 μm) and fem-toplankton (0.02–0.2 μm), as well as net plankton, ultrap ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protozoa
Protozoa (: protozoan or protozoon; alternative plural: protozoans) are a polyphyletic group of single-celled eukaryotes, either free-living or parasitic, that feed on organic matter such as other microorganisms or organic debris. Historically, protozoans were regarded as "one-celled animals". When first introduced by Georg Goldfuss, in 1818, the taxon Protozoa was erected as a class within the Animalia, with the word 'protozoa' meaning "first animals", because they often possess animal-like behaviours, such as motility and predation, and lack a cell wall, as found in plants and many algae. This classification remained widespread in the 19th and early 20th century, and even became elevated to a variety of higher ranks, including phylum, subkingdom, kingdom, and then sometimes included within the paraphyletic Protoctista or Protista. By the 1970s, it became usual to require that all taxa be monophyletic (derived from a common ancestor that would also be regarded as protozo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crustacean
Crustaceans (from Latin meaning: "those with shells" or "crusted ones") are invertebrate animals that constitute one group of arthropods that are traditionally a part of the subphylum Crustacea (), a large, diverse group of mainly aquatic arthropods including decapods (shrimps, prawns, crabs, lobsters and crayfish), seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, opossum shrimps, amphipods and mantis shrimp. The crustacean group can be treated as a subphylum under the clade Mandibulata. It is now well accepted that the hexapods (insects and entognathans) emerged deep in the Crustacean group, with the completed pan-group referred to as Pancrustacea. The three classes Cephalocarida, Branchiopoda and Remipedia are more closely related to the hexapods than they are to any of the other crustaceans ( oligostracans and multicrustaceans). The 67,000 described species range in size from '' Stygotantulus stocki'' at , to the Japanese ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tintinnid
Tintinnids are ciliates of the choreotrich order Tintinnida, the name deriving from a Latin source meaning a small tinkling bell. They are distinguished by vase-shaped shells called '' loricae'', which are mostly protein but may incorporate minute pieces of minerals. Fossil record Fossils resembling tintinnid loricas in shape and size, calpionellids, appear as early as the Ordovician period but are formed of calcite and as no extant ciliate taxa forms calcite shells they are unlikely to be tintinnids and probably not ciliates at all. Fossils which can be reliably related to extant tintinnids (e.g. fossils of agglutinated lorica) are in the fossil record during the Jurassic but do not become abundant until the Cretaceous. Tintinnids are an important part of the fossil record because of the rarity with which most other ciliates become preserved under the conditions of the marine environment. The loricae of some tintinnids are easily preserved, giving them a relatively good fossi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phaeodarea
Phaeodarea or Phaeodaria is a group of amoeboid cercozoan organisms. They are traditionally considered radiolarians, but in molecular trees do not appear to be close relatives of the other groups, and are instead placed among the Cercozoa. They are distinguished by the structure of their central capsule and by the presence of a phaeodium, an aggregate of waste particles within the cell. The term "Radiozoa" has been used to refer to radiolaria when Phaeodarea is explicitly excluded. Phaeodarea produce hollow skeletons composed of amorphous silica and organic material, which rarely fossilize. The endoplasm is divided by a cape with three openings, of which one gives rise to feeding pseudopods, and the others let through bundles of microtubules that support the axopods. Unlike true radiolarians, there are no cross-bridges between them. They also lack symbiotic algae, generally living below the photic zone, and do not produce any strontium sulfate. Characteristics Cell stru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coccolithophore
Coccolithophores, or coccolithophorids, are single-celled organisms which are part of the phytoplankton, the autotrophic (self-feeding) component of the plankton community. They form a group of about 200 species, and belong either to the kingdom Protista, according to Robert Whittaker (ecologist), Robert Whittaker's five-kingdom system, or clade Hacrobia, according to a newer biological classification system. Within the Hacrobia, the coccolithophores are in the phylum or division (botany), division Haptophyta, class Prymnesiophyceae (or Coccolithophyceae). Coccolithophores are almost exclusively Marine (ocean), marine, are photosynthesis, photosynthetic and mixotrophic, and exist in large numbers throughout the Photic zone, sunlight zone of the ocean. Coccolithophores are the most productive calcifying organisms on the planet, covering themselves with a calcium carbonate shell called a ''coccosphere''. However, the reasons they calcify remain elusive. One key function may be that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
