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Littorina Transgression
Littorina Sea (also Litorina Sea) is a geological brackish water stage of the Baltic Sea, which existed around 8500–4000 BP and followed the Mastogloia Sea (initial Littorina Sea), a transitional stage from the Ancylus Lake. This stage and form of the body of water is named after common periwinkle (''Littorina littorea''), then a prevailing mollusc in the waters, which indicates its salinity. Overview The last fully fresh water stage in the Baltic basin, the Ancylus Lake ended at 9,800 BP when salt water from the world ocean started entering the Mastogloia Sea in the Great Belt region commencing an initial Littorina Sea which as a saline or brackish sea continues to this day. These initial transgressions were incomplete and occurred at different times in different areas of the Baltic basin lasting until 8.5 ka cal. BP. The transition timings from fresh to brackish water that mark the onset of the Littorina Sea are not yet clearly defined. They may have been in th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Baltic History 5000-BC
Baltic may refer to: Peoples and languages *Baltic languages, a subfamily of Indo-European languages, including Lithuanian, Latvian and extinct Old Prussian *Balts (or Baltic peoples), ethnic groups speaking the Baltic languages and/or originating from the Baltic countries *Baltic Germans, historical ethnic German minority in Latvia and Estonia *Baltic Finnic peoples, the Finnic peoples historically inhabiting the area on the northeastern side of the Baltic sea Places Northern Europe * Baltic Sea, in Europe * Baltic region, an ambiguous term referring to the general area surrounding the Baltic Sea * Baltic states (also Baltic countries, Baltic nations, Baltics), a geopolitical term, currently referring to Estonia, Latvia and Lithuania * Baltic Provinces or governorates, former parts of the Swedish Empire and then Russian Empire (in modern Latvia, Estonia) * Baltic Shield, the exposed Precambrian northwest segment of the East European Craton * Baltic Plate, an ancient tectonic pla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Post-glacial Rebound
Post-glacial rebound (also called isostatic rebound or crustal rebound) is the rise of land masses after the removal of the huge weight of ice sheets during the last glacial period, which had caused isostatic depression. Post-glacial rebound and isostatic depression are phases of glacial isostasy (glacial isostatic adjustment, glacioisostasy), the deformation of the Earth's crust in response to changes in ice mass distribution. The direct raising effects of post-glacial rebound are readily apparent in parts of Northern Eurasia, Northern America, Patagonia, and Antarctica. However, through the processes of ''ocean siphoning'' and ''continental levering'', the effects of post-glacial rebound on sea level are felt globally far from the locations of current and former ice sheets.Milne, G.A., and J.X. Mitrovica (2008) ''Searching for eustasy in deglacial sea-level histories.'' Quaternary Science Reviews. 27:2292–2302. Overview During the last glacial period, much of northern Euro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Octactis
''Octactis'' is a genus of silicoflagellates, marine photosynthetic unicellular protists that take the form of either flagellates or axopodial amoebae. Described by Josef Schiller in 1925, ''Octactis'' contains various species of marine phytoplankton, some of them responsible for algal blooms that are toxic to fish. Characteristics ''Octactis'' species are unicellular protists that appear as several different multinucleate forms (i.e. with multiple nuclei). The most prevalent form is as amoebae surrounded by an external, basket-like siliceous skeleton, consisting of two conspicuous rings: a smaller apical ring supported by short struts that are attached to a larger basal ring. The skeleton pikes sometimes occur on the surface of the basal ring. The large window that the apical ring encloses is undivided. Other forms also present are naked amoebae and sometimes mucocyst-bearing amoebae. Both skeleton-bearing and naked cells present a long flagellum. The mucocysts appe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thalassionema Nitzschioides
''Thalassionema nitzschioides'' is a type of phytoplankton belonging to the pennate diatom A diatom (Neo-Latin ''diatoma'') is any member of a large group comprising several Genus, genera of algae, specifically microalgae, found in the oceans, waterways and soils of the world. Living diatoms make up a significant portion of Earth's B ... group. Characteristics *Length (apical axis): 10 - 110 μm *Width: 2 - 4 μm *Height: 3 - 8 μm *Marginal areolae: 10 - 12 in 10 μm ''Thalassionema nitzschioides'' are a yellow brown color. Their cells are straight and linear and they connect to form zigzagging chains. The cells are rectangular shaped, with rounded ends, and the cells are connected at the ends of each other. “Sometimes an apical spine is present and the marginal ornamentation is visible as ribs.” Global distribution ''Thalassionema nitzschioides'' can be found all over the world except in polar regions along shallow coastal ocean waters. They o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclotella
''Cyclotella'' is a genus of diatoms often found in oligotrophic environments, both marine and fresh water. It is in the family Stephanodiscaceae and the order Thalassiosirales. The genus was first discovered in the mid-1800s and since then has become an umbrella genus for over 100 different species, the most well-studied and the best known being '' Cyclotella meneghiniana''. Despite being among the most dominant genera in low-productivity environments, it is relatively understudied.Saros, J.E., Anderson, N.J. (2015). The ecology of the planktonic diatom Cyclotella and its implications for global environmental change studies. Biol Rev Camb Philos Soc. 90(2). 522-41. ''Cyclotella'' habitat has traditionally been described as low-productivity mesotrophic or oligotrophic freshwater environments. However, it is unclear whether there is an archetypal aquatic setting for this genus as some species are more cosmopolitan, such as ''C. meneghiniana,'' which occurs in warm, nutrient-rich ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chaetoceros
''Chaetoceros'' is a genus of diatoms in the family Chaetocerotaceae, first described by the German naturalist C. G. Ehrenberg in 1844. Species of this genus are mostly found in marine habitats, but a few species exist in freshwater. It is arguably the common and most diverse genus of marine planktonic diatoms, with over 200 accepted species. It is the type genus of its family. Species in the genus ''Chaetoceros'' are found in marine waters all over the world, where they can often form algal blooms. Some strains grow quickly and produce high amounts of lipids, sparking interest in potential usage for biofuels. Description ''Chaetoceros'' consists of cells linked together, forming long chains. Individual cells are elliptical to circular in valve view, making them centric diatoms, and are rectangular in girdle view. Like other diatoms, cells of ''Chaetoceros'' are surrounded by siliceous cell walls known as frustules. Each frustule has four hollow processes called setae, o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aulacoseira
''Aulacoseira'' is a genus of diatoms belonging to the family Aulacoseiraceae. The genus has cosmopolitan distribution In biogeography, a cosmopolitan distribution is the range of a taxon that extends across most or all of the surface of the Earth, in appropriate habitats; most cosmopolitan species are known to be highly adaptable to a range of climatic and en .... Species: *'' Aulacoseira accincta'' *'' Aulacoseira acicularia'' *'' Aulacoseira aculeifera'' *'' Aulacoseira granulata'' References Diatoms Diatom genera {{diatom-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Øresund
Øresund or Öresund (, ; ; ), commonly known in English as the Sound, is a strait which forms the Denmark–Sweden border, Danish–Swedish border, separating Zealand (Denmark) from Scania (Sweden). The strait has a length of ; its width varies from to . The narrowest point is between Helsingør in Denmark and Helsingborg in Sweden. Øresund, along with the Great Belt, the Little Belt and the Kiel Canal, is one of four waterways that connect the Baltic Sea to the Atlantic Ocean via Kattegat, Skagerrak, and the North Sea; this makes it one of the busiest waterways in the world. The Øresund Bridge, between the Danish capital Copenhagen and the Swedish city of Malmö, inaugurated on 1 July 2000, connects a bi-national Øresund Region, metropolitan area with close to 4 million inhabitants. The HH Ferry route, between Helsingør, Denmark and Helsingborg, Sweden, in the northern part of Øresund, is one of the world's busiest international ferry routes, with more than 70 departu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Halocline
A halocline (or salinity chemocline), from the Greek words ''hals'' (salt) and ''klinein'' (to slope), refers to a layer within a body of water ( water column) where there is a sharp change in salinity (salt concentration) with depth. Haloclines are typically found in oceans or large estuaries and it is a type of chemical stratification that is most commonly found in places where freshwater from rivers or melting ice, mixes with salty ocean water. Description In the midlatitudes, an excess of evaporation over precipitation leads to surface waters being saltier than deep waters. In such regions, the vertical stratification is due to surface waters being warmer than deep waters and the halocline is destabilizing. Such regions may be prone to salt fingering, a process which results in the preferential mixing of salinity. In these regions, the halocline is important in allowing for the formation of sea ice, and limiting the escape of carbon dioxide to the atmosphere. In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diatom
A diatom (Neo-Latin ''diatoma'') is any member of a large group comprising several Genus, genera of algae, specifically microalgae, found in the oceans, waterways and soils of the world. Living diatoms make up a significant portion of Earth's Biomass (ecology), biomass. They generate about 20 to 50 percent of the oxygen produced on the planet each year, take in over 6.7 billion tonnes of silicon each year from the waters in which they live, and constitute nearly half of the organic material found in the oceans. The Protist shell, shells of dead diatoms are a significant component of marine sediment, and the entire Amazon basin is fertilized annually by 27 million tons of diatom shell dust transported by transatlantic winds from the African Sahara, much of it from the Bodélé Depression, which was once made up of a system of fresh-water lakes. Diatoms are unicellular organisms: they occur either as solitary cells or in Colony (biology), colonies, which can take the shape of ribb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atlantic Period
The Atlantic in palaeoclimatology was the warmest and moistest Blytt–Sernander period, pollen zone and chronozone of Holocene northern Europe. The climate was generally warmer than today. It was preceded by the Boreal, with a climate similar to today's, and was followed by the Subboreal, a transition to the modern. Because it was the warmest period of the Holocene, the Atlantic is often referenced more directly as the Holocene climatic optimum, or just climatic optimum. Subdividing the Atlantic The Atlantic is equivalent to pollen zone VII. Sometimes a Pre-atlantic or early Atlantic is distinguished, on the basis of an early dividing cold snap. Other scientists place the Atlantic entirely after the cold snap, assigning the latter to the Boreal. The period is still in the process of definition. Dating Beginning of the Atlantic period It is a question of definition and the criteria: Beginning with the temperatures, as derivable from Greenland ice core data, it is possibl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
