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Botn (Trøndelag)
Botn (also called ''Rissa-Botn'') is an inland fjord in the Rissa area of the municipality of Indre Fosen in Trøndelag county, Norway. It flows through a short, small river into the Sundsbukta, a small bay off the Trondheimsfjorden. The village of Årnset lies on the north shore of Botn. Hydrography and water quality The extraordinarily shallow, narrow, and long inlet restrains the water exchange severely. The daily tidal amplitude is in the order of centimetres, about 1/10 of the tidal amplitude of the supplying Trondheimsfjord. The shallow river connecting Botn to the Trondheimsfjord blocks out more than half of the tidal wave, making the moon-phase driven tidal flood height cycles the primal driving force for the internal water level, with an abnormally small neap flood effect (zero has been observed during lowest neap tides and meteorologically suppressed sea level). In addition, the inlet is connected to a secluded bay sheltered from the strong tidal currents in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Indre Fosen
Indre Fosen is a municipality in Trøndelag county, Norway. It is located in the traditional district of Fosen. The administrative centre of the municipality is the village of Årnset. Other villages in Indre Fosen include Askjem, Dalbygda, Hasselvika, Husbysjøen, Leira, Leksvik, Råkvåg, Rørvika, Seter, Stadsbygd, Verrabotn, and Vanvikan. The Norwegian County Road 755 runs through the municipality. The municipality is the 102nd largest by area out of the 356 municipalities in Norway. Indre Fosen is the 113th most populous municipality in Norway with a population of 9,899. The municipality's population density is and its population has decreased by 1.7% over the previous 10-year period. General information The municipality was established on 1 January 2018, the same day that Trøndelag county was established. Indre Fosen straddles the former county border, as it was formed by the unification of the neighboring municipalities of Leksvik (formerly in Nord-Trøndelag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bottom Water
Bottom water is the lowermost water mass in a water body, by its bottom, with distinct characteristics, in terms of physics, chemistry, and ecology. Oceanography Bottom water consists of cold, dense water near the ocean floor. This water is characterized by low salinity and nutrient content. Generally, low salinity from seasonal ice melt and freshwater river output characterizes bottom water produced in the Antarctic. However, during colder months, the formation of sea ice is a crucial process that raises the salinity of bottom water through brine rejection. As saltwater freezes, salt is expelled from the ice into the surrounding water. The oxygen content in bottom water is high due to ocean circulation. In the Antarctic, salty and cold surface water sinks to lower depths due to its high density. As the surface water sinks, it carries oxygen from the surface with it and will spend an enormous amount of time circulating across the seafloor of ocean basins. Oxygen-rich water moving th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tsunami
A tsunami ( ; from ja, 津波, lit=harbour wave, ) is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a large lake. Earthquakes, volcanic eruptions and other underwater explosions (including detonations, landslides, glacier calvings, meteorite impacts and other disturbances) above or below water all have the potential to generate a tsunami. Unlike normal ocean waves, which are generated by wind, or tides, which are in turn generated by the gravitational pull of the Moon and the Sun, a tsunami is generated by the displacement of water from a large event. Tsunami waves do not resemble normal undersea currents or sea waves because their wavelength is far longer. Rather than appearing as a breaking wave, a tsunami may instead initially resemble a rapidly rising tide. For this reason, it is often referred to as a tidal wave, although this usage is not favoured by the scientific community because it might give ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quick Clay
Quick clay, also known as Leda clay and Champlain Sea clay in Canada, is any of several distinctively sensitive glaciomarine clays found in Canada, Norway, Russia, Sweden, Finland, the United States and other locations around the world. The clay is so unstable that when a mass of quick clay is subjected to sufficient stress, the material behavior may drastically change from that of a particulate material to that of a watery fluid. Landslides occur because of the sudden soil liquefaction caused by external sollicitations such as vibrations induced by an earthquake, or massive rainfalls. Quick clay main deposits Quick clay is found only in countries close to the north pole, such as Russia; Canada; Norway; Sweden; and Finland; and in Alaska, United States; since they were glaciated during the Pleistocene epoch. In Canada, the clay is associated primarily with the Pleistocene-era Champlain Sea, in the modern Ottawa Valley, the St. Lawrence Valley, and the Saguenay River regions. Qu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Norwegian Academy Of Science And Letters
The Norwegian Academy of Science and Letters ( no, Det Norske Videnskaps-Akademi, DNVA) is a learned society based in Oslo, Norway. Its purpose is to support the advancement of science and scholarship in Norway. History The Royal Frederick University in Christiania was established in 1811. The idea of a learned society in Christiania surfaced for the first time in 1841. The city of Trondhjem had no university, but had a learned society, the Royal Norwegian Society of Sciences and Letters, established in 1760. The purpose of a learned society in Christiania was to support scientific studies and aid publication of academic papers. The idea of the Humboldt-inspired university, where independent research stood strong, had taken over for the instrumental view of a university as a means to produce civil servants. The city already had societies for specific professions, for instance the Norwegian Medical Society which was founded in 1833. However, these societies were open for both acad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Algal Bloom
An algal bloom or algae bloom is a rapid increase or accumulation in the population of algae in freshwater or marine water systems. It is often recognized by the discoloration in the water from the algae's pigments. The term ''algae'' encompasses many types of aquatic photosynthetic organisms, both macroscopic multicellular organisms like seaweed and microscopic unicellular organisms like cyanobacteria. ''Algal bloom'' commonly refers to the rapid growth of microscopic unicellular algae, not macroscopic algae. An example of a macroscopic algal bloom is a kelp forest. Algal blooms are the result of a nutrient, like nitrogen or phosphorus from various sources (for example fertilizer runoff or other forms of nutrient pollution), entering the aquatic system and causing excessive growth of algae. An algal bloom affects the whole ecosystem. Consequences range from the benign feeding of higher trophic levels to more harmful effects like blocking sunlight from reaching other organ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ecological Crisis
An ecological or environmental crises occurs when changes to the environment of a species or population destabilizes its continued survival. Some of the important causes include: * Degradation of an abiotic ecological factor (for example, increase of temperature, less significant rainfalls) * Increased pressures from predation * Rise in the number of individuals (i.e. overpopulation) The evolutionary theory of punctuated equilibrium sees infrequent ecological crises as a potential driver of rapid evolution. Because of the impact of humans on the natural environment in the recent geological period, the term ecological crisis is often applied to environmental issues caused by human civilizations such as: the climate crisis, biodiversity loss and plastic pollution which have emerged as major global challenges during the first few decades of the 21st century. Examples Crises caused by abiotic factors Climate change is starting to have major impacts on ecosystems. With globa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eutrophication
Eutrophication is the process by which an entire body of water, or parts of it, becomes progressively enriched with minerals and nutrients, particularly nitrogen and phosphorus. It has also been defined as "nutrient-induced increase in phytoplankton productivity". Water bodies with very low nutrient levels are termed oligotrophic and those with moderate nutrient levels are termed mesotrophic. Advanced eutrophication may also be referred to as dystrophic and hypertrophic conditions. Eutrophication can affect freshwater or salt water systems. In freshwater ecosystems it is almost always caused by excess phosphorus. In coastal waters on the other hand, the main contributing nutrient is more likely to be nitrogen, or nitrogen and phosphorus together. This depends on the location and other factors. When occurring naturally, eutrophication is a very slow process in which nutrients, especially phosphorus compounds and organic matter, accumulate in water bodies. These nutrients deriv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing military alliances: the Allies and the Axis powers. World War II was a total war that directly involved more than 100 million personnel from more than 30 countries. The major participants in the war threw their entire economic, industrial, and scientific capabilities behind the war effort, blurring the distinction between civilian and military resources. Aircraft played a major role in the conflict, enabling the strategic bombing of population centres and deploying the only two nuclear weapons ever used in war. World War II was by far the deadliest conflict in human history; it resulted in 70 to 85 million fatalities, mostly among civilians. Tens of millions died due to genocides (including the Holocaust), starvation, ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mussel
Mussel () is the common name used for members of several families of bivalve molluscs, from saltwater and Freshwater bivalve, freshwater habitats. These groups have in common a shell whose outline is elongated and asymmetrical compared with other edible clams, which are often more or less rounded or oval. The word "mussel" is frequently used to mean the bivalves of the marine family Mytilidae, most of which live on exposed shores in the intertidal zone, attached by means of their strong Byssus, byssal threads ("beard") to a firm substrate. A few species (in the genus ''Bathymodiolus'') have colonised hydrothermal vents associated with deep ocean ridges. In most marine mussels the shell is longer than it is wide, being wedge-shaped or asymmetrical. The external colour of the shell is often dark blue, blackish, or brown, while the interior is silvery and somewhat nacreous. The common name "mussel" is also used for many freshwater bivalves, including the freshwater pearl mussels. F ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seaweed
Seaweed, or macroalgae, refers to thousands of species of macroscopic, multicellular, marine algae. The term includes some types of '' Rhodophyta'' (red), ''Phaeophyta'' (brown) and ''Chlorophyta'' (green) macroalgae. Seaweed species such as kelps provide essential nursery habitat for fisheries and other marine species and thus protect food sources; other species, such as planktonic algae, play a vital role in capturing carbon, producing at least 50% of Earth's oxygen. Natural seaweed ecosystems are sometimes under threat from human activity. For example, mechanical dredging of kelp destroys the resource and dependent fisheries. Other forces also threaten some seaweed ecosystems; a wasting disease in predators of purple urchins has led to a urchin population surge which destroyed large kelp forest regions off the coast of California. Humans have a long history of cultivating seaweeds for their uses. In recent years, seaweed farming has become a global agricultural practic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrodynamics
In physics and engineering, fluid dynamics is a subdiscipline of fluid mechanics that describes the flow of fluids—liquids and gases. It has several subdisciplines, including ''aerodynamics'' (the study of air and other gases in motion) and hydrodynamics (the study of liquids in motion). Fluid dynamics has a wide range of applications, including calculating forces and moments on aircraft, determining the mass flow rate of petroleum through pipelines, predicting weather patterns, understanding nebulae in interstellar space and modelling fission weapon detonation. Fluid dynamics offers a systematic structure—which underlies these practical disciplines—that embraces empirical and semi-empirical laws derived from flow measurement and used to solve practical problems. The solution to a fluid dynamics problem typically involves the calculation of various properties of the fluid, such as flow velocity, pressure, density, and temperature, as functions of space and time. Bef ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
