Organic matterOrganic matter, organic material, or natural organic matter refers to the large source of carbon-based compounds found within natural and engineered, terrestrial, and aquatic environments. It is matter composed of organic compounds that have come from the feces and remains of organisms such as plants and animals. Organic molecules can also be made by chemical reactions that do not involve life. Basic structures are created from cellulose, tannin, cutin, and lignin, along with other various proteins, lipids, and carbohydrates.
Hypoxia (environmental)Hypoxia refers to low oxygen conditions. Normally, 20.9% of the gas in the atmosphere is oxygen. The partial pressure of oxygen in the atmosphere is 20.9% of the total barometric pressure. In water, oxygen levels are much lower, approximately 7 ppm or 0.0007% in good quality water, and fluctuate locally depending on the presence of photosynthetic organisms and relative distance to the surface (if there is more oxygen in the air, it will diffuse across the partial pressure gradient).
Trophic state indexThe Trophic State Index (TSI) is a classification system designed to rate water bodies based on the amount of biological productivity they sustain. Although the term "trophic index" is commonly applied to lakes, any surface water body may be indexed. The TSI of a water body is rated on a scale from zero to one hundred. Under the TSI scale, water bodies may be defined as: oligotrophic (TSI 0–40, having the least amount of biological productivity, "good" water quality); mesotrophic (TSI 40–60, having a moderate level of biological productivity, "fair" water quality); or eutrophic to hypereutrophic (TSI 60–100, having the highest amount of biological productivity, "poor" water quality).
Kelp forestKelp forests are underwater areas with a high density of kelp, which covers a large part of the world's coastlines. Smaller areas of anchored kelp are called kelp beds. They are recognized as one of the most productive and dynamic ecosystems on Earth. Although algal kelp forest combined with coral reefs only cover 0.1% of Earth's total surface, they account for 0.9% of global primary productivity. Kelp forests occur worldwide throughout temperate and polar coastal oceans.
Balanced budgetA balanced budget (particularly that of a government) is a budget in which revenues are equal to expenditures. Thus, neither a budget deficit nor a budget surplus exists (the accounts "balance"). More generally, it is a budget that has no budget deficit, but could possibly have a budget surplus. A cyclically balanced budget is a budget that is not necessarily balanced year-to-year but is balanced over the economic cycle, running a surplus in boom years and running a deficit in lean years, with these offsetting over time.
History of RussiaThe history of Russia begins with the histories of the East Slavs. The traditional start-date of specifically Russian history is the establishment of the Rus' state in the north in 862, ruled by Varangians. Staraya Ladoga and Novgorod became the first major cities of the new union of immigrants from Scandinavia with the Slavs and Finns. In 882, Prince Oleg of Novgorod seized Kiev, thereby uniting the northern and southern lands of the Eastern Slavs under one authority, moving the governance center to Kiev by the end of the 10th century, and maintaining northern and southern parts with significant autonomy from each other.
UpwellingUpwelling is an oceanographic phenomenon that involves wind-driven motion of dense, cooler, and usually nutrient-rich water from deep water towards the ocean surface. It replaces the warmer and usually nutrient-depleted surface water. The nutrient-rich upwelled water stimulates the growth and reproduction of primary producers such as phytoplankton. The biomass of phytoplankton and the presence of cool water in those regions allow upwelling zones to be identified by cool sea surface temperatures (SST) and high concentrations of chlorophyll a.
Ekman transportEkman transport is part of Ekman motion theory, first investigated in 1902 by Vagn Walfrid Ekman. Winds are the main source of energy for ocean circulation, and Ekman transport is a component of wind-driven ocean current. Ekman transport occurs when ocean surface waters are influenced by the friction force acting on them via the wind. As the wind blows it casts a friction force on the ocean surface that drags the upper 10-100m of the water column with it.
Soviet famine of 1930–1933The Soviet famine of 1930–1933 was a famine in the major grain-producing areas of the Soviet Union, including Ukraine and different parts of Russia, including Northern Caucasus, Kuban Region, Volga Region, Kazakhstan, the South Urals, and West Siberia. Estimates conclude that 5.7 to 8.7 million people died of famine across the Soviet Union. Major contributing factors to the famine include: the forced collectivization of agriculture as a part of the First Five-Year Plan, and forced grain procurement, combined with rapid industrialization and a decreasing agricultural workforce.
EcoregionAn ecoregion (ecological region) is an ecologically and geographically defined area that is smaller than a bioregion, which in turn is smaller than a biogeographic realm. Ecoregions cover relatively large areas of land or water, and contain characteristic, geographically distinct assemblages of natural communities and species. The biodiversity of flora, fauna and ecosystems that characterise an ecoregion tends to be distinct from that of other ecoregions.
