DiatomA diatom (Neo-Latin diatoma) is any member of a large group comprising several genera of algae, specifically microalgae, found in the oceans, waterways and soils of the world. Living diatoms make up a significant portion of the Earth's 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.
Community (ecology)In ecology, a community is a group or association of populations of two or more different species occupying the same geographical area at the same time, also known as a biocoenosis, biotic community, biological community, ecological community, or life assemblage. The term community has a variety of uses. In its simplest form it refers to groups of organisms in a specific place or time, for example, "the fish community of Lake Ontario before industrialization".
ScandinaviaScandinavia is a subregion in Northern Europe, with strong historical, cultural, and linguistic ties between its constituent peoples. Scandinavia most commonly refers to Denmark, Norway, and Sweden. In English usage, it can sometimes also refer more narrowly to the Scandinavian Peninsula (which excludes Denmark but includes part of Finland), or more broadly to all of the Nordic countries, also including Finland, Iceland, and the Faroe Islands.
History of ScandinaviaThe history of Scandinavia is the history of the geographical region of Scandinavia and its peoples. The region is located in Northern Europe, and consists of Denmark, Norway and Sweden. Finland and Iceland are at times, especially in English-speaking contexts, considered part of Scandinavia. Scandinavian prehistory Little evidence remains in Scandinavia of the Stone Age, the Bronze Age, or the Iron Age except limited numbers of tools created from stone, bronze, and iron, some jewelry and ornaments, and stone burial cairns.
Carpathian MountainsThe Carpathian Mountains or Carpathians (kɑrˈpeɪθiənz) are a range of mountains forming an arc across Central Europe. Roughly long, it is the third-longest European mountain range after the Urals at and the Scandinavian Mountains at . The range stretches from the far eastern Czech Republic (3%) and Austria (1%) in the northwest through Slovakia (21%), Poland (10%), Ukraine (10%), Romania (50%) to Serbia (5%) in the south. The highest range within the Carpathians is known as the Tatra mountains in Slovakia, where the highest peaks exceed .
SiltSilt is granular material of a size between sand and clay and composed mostly of broken grains of quartz. Silt may occur as a soil (often mixed with sand or clay) or as sediment mixed in suspension with water. Silt usually has a floury feel when dry, and lacks plasticity when wet. Silt also can be felt by the tongue as granular when placed on the front teeth (even when mixed with clay particles). Silt is a common material, making up 45% of average modern mud.
ScreeScree is a collection of broken rock fragments at the base of a cliff or other steep rocky mass that has accumulated through periodic rockfall. Landforms associated with these materials are often called talus deposits. Talus deposits typically have a concave upwards form, where the maximum inclination corresponds to the angle of repose of the mean debris particle size. The exact definition of scree in the primary literature is somewhat relaxed, and it often overlaps with both talus and colluvium.
Species evennessSpecies evenness describes the commonness or rarity of a species; it requires knowing the abundance of each species relative to those of the other species within the community. Abundance values can be difficult to obtain. Area-based counts, distance methods, and mark–recapture studies are the three general categories of methods for estimating abundance. Species evenness is combined with species richness, (the number of species in the community), in order to determine species diversity, which is an important measure of community structure.
BeggiatoaBeggiatoa is a genus of Gammaproteobacteria belonging to the order Thiotrichales, in the Pseudomonadota phylum. This genus was one of the first bacteria discovered by Ukrainian botanist Sergei Winogradsky. During his research in Anton de Bary's laboratory of botany in 1887, he found that Beggiatoa oxidized hydrogen sulfide (H2S) as an energy source, forming intracellular sulfur droplets, oxygen is the terminal electron acceptor and CO2 is used as a carbon source.
Competitive exclusion principleIn ecology, the competitive exclusion principle, sometimes referred to as Gause's law, is a proposition that two species which compete for the same limited resource cannot coexist at constant population values. When one species has even the slightest advantage over another, the one with the advantage will dominate in the long term. This leads either to the extinction of the weaker competitor or to an evolutionary or behavioral shift toward a different ecological niche.
