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Aquatic Ecology
An aquatic ecosystem is an ecosystem formed by surrounding a body of water, in contrast to land-based terrestrial ecosystems. Aquatic ecosystems contain communities of organisms that are dependent on each other and on their environment. The two main types of aquatic ecosystems are marine ecosystems and freshwater ecosystems. Freshwater ecosystems may be lentic (slow moving water, including pools, ponds, and lakes); lotic (faster moving water, for example streams and rivers); and wetlands (areas where the soil is saturated or inundated for at least part of the time). Types Marine ecosystems Marine coastal ecosystem Marine surface ecosystem Freshwater ecosystems Lentic ecosystem (lakes) Lotic ecosystem (rivers) Wetlands Functions Aquatic ecosystems perform many important environmental functions. For example, they recycle nutrients, purify water, attenuate floods, recharge ground water and provide habitats for wildlife. Aquatic ecosystems are also used f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biogeochemical Cycle
A biogeochemical cycle (or more generally a cycle of matter) is the pathway by which a chemical substance cycles (is turned over or moves through) the biotic and the abiotic compartments of Earth. The biotic compartment is the biosphere and the abiotic compartments are the atmosphere, hydrosphere and lithosphere. There are biogeochemical cycles for chemical elements, such as for calcium, carbon, hydrogen, mercury, nitrogen, oxygen, phosphorus, selenium, iron and sulfur, as well as molecular cycles, such as for water and silica. There are also macroscopic cycles, such as the rock cycle, and human-induced cycles for synthetic compounds such as polychlorinated biphenyls (PCBs). In some cycles there are reservoirs where a substance can remain or be sequestered for a long period of time. Overview Energy flows directionally through ecosystems, entering as sunlight (or inorganic molecules for chemoautotrophs) and leaving as heat during the many transfers between trophic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Euryhaline
Euryhaline organisms are able to adapt to a wide range of salinities. An example of a euryhaline fish is the molly (''Poecilia sphenops'') which can live in fresh water, brackish water, or salt water. The green crab ('' Carcinus maenas'') is an example of a euryhaline invertebrate that can live in salt and brackish water. Euryhaline organisms are commonly found in habitats such as estuaries and tide pools where the salinity changes regularly. However, some organisms are euryhaline because their life cycle involves migration between freshwater and marine environments, as is the case with salmon and eels. The opposite of euryhaline organisms are stenohaline ones, which can only survive within a narrow range of salinities. Most freshwater organisms are stenohaline, and will die in seawater, and similarly most marine organisms are stenohaline, and cannot live in fresh water. Osmoregulation Osmoregulation is the active process by which an organism maintains its level of water ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biomass
Biomass is plant-based material used as a fuel for heat or electricity production. It can be in the form of wood, wood residues, energy crops, agricultural residues, and waste from industry, farms, and households. Some people use the terms biomass and biofuel interchangeably, while others consider biofuel to be a ''liquid'' or ''gaseous'' fuel used for transportation, as defined by government authorities in the US and EU. The European Union's Joint Research Centre defines solid biofuel as raw or processed organic matter of biological origin used for energy, such as firewood, wood chips, and wood pellets. In 2019, biomass was used to produce 57 EJ ( exajoules) of energy, compared to 190 EJ from crude oil, 168 EJ from coal, 144 EJ from natural gas, 30 EJ from nuclear, 15 EJ from hydro and 13 EJ from wind, solar and geothermal combined. Approximately 86% of modern bioenergy is used for heating applications, with 9% used for transport and 5% for electricity. Most of the glob ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heterotrophic
A heterotroph (; ) is an organism that cannot produce its own food, instead taking nutrition from other sources of organic carbon, mainly plant or animal matter. In the food chain, heterotrophs are primary, secondary and tertiary consumers, but not producers. Living organisms that are heterotrophic include all animals and fungi, some bacteria and protists, and many parasitic plants. The term heterotroph arose in microbiology in 1946 as part of a classification of microorganisms based on their type of nutrition. The term is now used in many fields, such as ecology in describing the food chain. Heterotrophs may be subdivided according to their energy source. If the heterotroph uses chemical energy, it is a chemoheterotroph (e.g., humans and mushrooms). If it uses light for energy, then it is a photoheterotroph (e.g., green non-sulfur bacteria). Heterotrophs represent one of the two mechanisms of nutrition (trophic levels), the other being autotrophs (''auto'' = self, ''troph' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cambridge University Press
Cambridge University Press is the university press of the University of Cambridge. Granted letters patent by King Henry VIII in 1534, it is the oldest university press in the world. It is also the King's Printer. Cambridge University Press is a department of the University of Cambridge and is both an academic and educational publisher. It became part of Cambridge University Press & Assessment, following a merger with Cambridge Assessment in 2021. With a global sales presence, publishing hubs, and offices in more than 40 countries, it publishes over 50,000 titles by authors from over 100 countries. Its publishing includes more than 380 academic journals, monographs, reference works, school and university textbooks, and English language teaching and learning publications. It also publishes Bibles, runs a bookshop in Cambridge, sells through Amazon, and has a conference venues business in Cambridge at the Pitt Building and the Sir Geoffrey Cass Sports and Social Centre. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calyptogena Magnifica
''Calyptogena magnifica'' is a species of giant white clam found clustered around hydrothermal vents at abyssal depths in the Pacific Ocean. Description The systematics of the family Vesicomyidae is unclear because of the small number of specimens collected, the variability between specimens of the same species and their wide dispersal in isolated, deep water locations. The morphology of ''Calyptogena magnifica'' resembles another member of the genus, '' Calyptogena elongata'', the type locality of which is several hundred miles further north. ''C elongata'' is only known from three small specimens and the size of mature individuals is unknown. The two valves of ''Calyptogena magnifica'' are oval or slightly kidney-shaped and about two times as long as they are high. The umbones are towards the anterior end of the valve and the growth rings are most noticeable near the margins. The shell material is thick and the exterior is white and usually chalky in appearance. The perios ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Giant Tube Worm
''Riftia pachyptila'', commonly known as the giant tube worm and less commonly known as the Giant beardworm, is a marine invertebrate in the phylum Annelida (formerly grouped in phylum Pogonophora and Vestimentifera) related to tube worms commonly found in the intertidal and pelagic zones. ''R. pachyptila'' lives on the floor of the Pacific Ocean near hydrothermal vents, the vents provide a natural ambient temperature in their environment ranging from 2 to 30 °C, at the same time it can tolerate extremely high hydrogen sulfide levels. These worms can reach a length of , and their tubular bodies have a diameter of . Its common name "giant tube worm" is, however, also applied to the largest living species of shipworm, '' Kuphus polythalamius'', which despite the name "worm", is a bivalve mollusc rather than an annelid. Discovery ''R. pachyptila'' was discovered in 1977 on an expedition of the American bathyscaphe DSV ''Alvin'' to the Galápagos Rift led ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcanic Vent
A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plates are diverging or converging, and most are found underwater. For example, a mid-ocean ridge, such as the Mid-Atlantic Ridge, has volcanoes caused by divergent tectonic plates whereas the Pacific Ring of Fire has volcanoes caused by convergent tectonic plates. Volcanoes can also form where there is stretching and thinning of the crust's plates, such as in the East African Rift and the Wells Gray-Clearwater volcanic field and Rio Grande rift in North America. Volcanism away from plate boundaries has been postulated to arise from upwelling diapirs from the core–mantle boundary, deep in the Earth. This results in hotspot volcanism, of which the Hawaiian hotspot is an example. Volcanoes are usually not created where two tectonic plates slide ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen Sulfide
Hydrogen sulfide is a chemical compound with the formula . It is a colorless chalcogen-hydride gas, and is poisonous, corrosive, and flammable, with trace amounts in ambient atmosphere having a characteristic foul odor of rotten eggs. The underground mine gas term for foul-smelling hydrogen sulfide-rich gas mixtures is ''stinkdamp''. Swedish chemist Carl Wilhelm Scheele is credited with having discovered the chemical composition of purified hydrogen sulfide in 1777. The British English spelling of this compound is hydrogen sulphide, a spelling no longer recommended by the Royal Society of Chemistry or the International Union of Pure and Applied Chemistry. Hydrogen sulfide is toxic to humans and most other animals by inhibiting cellular respiration in a manner similar to hydrogen cyanide. When it is inhaled or it or its salts are ingested in high amounts, damage to organs occurs rapidly with symptoms ranging from breathing difficulties to convulsions and death. Despite this, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autotroph
An autotroph or primary producer is an organism that produces complex organic compounds (such as carbohydrates, fats, and proteins) using carbon from simple substances such as carbon dioxide,Morris, J. et al. (2019). "Biology: How Life Works", 3rd edition, W. H. Freeman. generally using energy from light ( photosynthesis) or inorganic chemical reactions ( chemosynthesis). They convert an abiotic source of energy (e.g. light) into energy stored in organic compounds, which can be used by other organisms (e.g. heterotrophs). Autotrophs do not need a living source of carbon or energy and are the producers in a food chain, such as plants on land or algae in water (in contrast to heterotrophs as consumers of autotrophs or other heterotrophs). Autotrophs can reduce carbon dioxide to make organic compounds for biosynthesis and as stored chemical fuel. Most autotrophs use water as the reducing agent, but some can use other hydrogen compounds such as hydrogen sulfide. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aerenchyma
Aerenchyma or aeriferous parenchyma or lacunae, is a modification of the parenchyma to form a spongy tissue that creates spaces or air channels in the leaves, stems and roots of some plants, which allows exchange of gases between the shoot and the root. The channels of air-filled cavities (see image to right) provide a low-resistance internal pathway for the exchange of gases such as oxygen, carbondioxide and ethylene between the plant above the water and the submerged tissues. Aerenchyma is also widespread in aquatic and wetland plants which must grow in hypoxic soils. The word "aerenchyma" is Modern Latin derived from Latin ' for "air" and Greek ' for "infusion." Aerenchyma formation and hypoxia When soil is flooded, hypoxia develops, as soil microorganisms consume oxygen faster than diffusion occurs. The presence of hypoxic soils is one of the defining characteristics of wetlands. Many wetland plants possess aerenchyma, and in some, such as water-lilies, there is mass flow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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