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Siliceous Ooze
Siliceous ooze is a type of biogenic pelagic sediment located on the Abyssal, deep ocean floor. Siliceous oozes are the least common of the deep sea sediments, and make up approximately 15% of the ocean floor. Oozes are defined as sediments which contain at least 30% skeletal remains of pelagic microorganisms. Siliceous oozes are largely composed of the silica based skeletons of microscopic marine organisms such as diatoms and radiolarians. Other components of siliceous oozes near continental margins may include terrestrially derived silica particles and sponge spicules. Siliceous oozes are composed of skeletons made from opal silica SiO2, SiO2·''n''H2O, as opposed to calcareous oozes, which are made from skeletons of calcium carbonate (CaCO3, CaCO3SiO2, ·''n''H2O) organisms (i.e. coccolithophores). Silicon (Si) is a bioessential element and is efficiently recycled in the marine environment through the silica cycle. Distance from land masses, water depth and ocean fertility are al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Centric Diatom (3075277530)
The Coscinodiscophyceae are a proposed class(s) of diatoms. They are similar to the Centrales, a traditional, paraphyletic subdivision of the heterokont algae known as diatoms. The order is named for the shape of the cell wall#Diatom cell walls, cell walls (or valves or frustules) of centric diatoms, which are circular or ellipsoid in valve view. The valves often bear Symmetry (biology), radially symmetrical ornamental patterns that can appear as dots when viewed with an optical microscope. Some also bear spines on their valves, which may either increase cell surface area and reduce sinking, or act as a deterrent to zooplankton grazers. Unlike pennate diatoms, centric diatoms never have a raphe. In terms of cell cycle, vegetative reproduction, vegetative cells are diploid and undergo mitosis during normal cell division. In sexual species, oogamy, oogamous meiosis produces haploid gametes, either ovum, ova or sperm cells. These fuse to produce a zygote which expands in size t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chert
Chert () is a hard, fine-grained sedimentary rock composed of microcrystalline or cryptocrystalline quartz, the mineral form of silicon dioxide (SiO2). Chert is characteristically of biological origin, but may also occur inorganically as a precipitation (chemistry), chemical precipitate or a diagenesis, diagenetic replacement, as in petrified wood. Chert is typically composed of the petrified remains of siliceous ooze, the biogenic sediment that covers large areas of the deep ocean floor, and which contains the silicon skeletal remains of diatoms, Dictyochales, silicoflagellates, and radiolarians. Precambrian cherts are notable for the presence of fossil cyanobacteria. In addition to Micropaleontology, microfossils, chert occasionally contains macrofossils. However, some chert is devoid of any fossils. Chert varies greatly in color, from white to black, but is most often found as gray, brown, grayish brown and light green to rusty redW.L. Roberts, T.J. Campbell, G.R. Rapp Jr., ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iron Fertilization
Iron fertilization is the intentional introduction of iron-containing compounds (like iron sulfate) to iron-poor areas of the ocean surface to stimulate phytoplankton production. This is intended to enhance biological productivity and/or accelerate carbon dioxide () sequestration from the atmosphere. Iron is a trace element necessary for photosynthesis in plants. It is highly insoluble in sea water and in a variety of locations is the limiting nutrient for phytoplankton growth. Large algal blooms can be created by supplying iron to iron-deficient ocean waters. These blooms can nourish other organisms. Ocean iron fertilization is an example of a geoengineering technique. Iron fertilization attempts to encourage phytoplankton growth, which removes carbon from the atmosphere for at least a period of time. This technique is controversial because there is limited understanding of its complete effects on the marine ecosystem, including side effects and possibly large deviations ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbon Sequestration
Carbon sequestration is the process of storing carbon in a carbon pool. It plays a crucial role in Climate change mitigation, limiting climate change by reducing the amount of Carbon dioxide in Earth's atmosphere, carbon dioxide in the atmosphere. There are two main types of carbon sequestration: biologic (also called ''biosequestration'') and geologic. Biologic carbon sequestration is a naturally occurring process as part of the carbon cycle. Humans can enhance it through deliberate actions and use of technology. Carbon dioxide () is naturally captured from the atmosphere through biological, chemical, and physical processes. These processes can be accelerated for example through changes in land use and agricultural practices, called carbon farming. Artificial processes have also been devised to produce similar effects. This approach is called carbon capture and storage. It involves using technology to capture and sequester (store) that is produced from human activities under ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Industrial Revolution
The Industrial Revolution, sometimes divided into the First Industrial Revolution and Second Industrial Revolution, was a transitional period of the global economy toward more widespread, efficient and stable manufacturing processes, succeeding the Second Agricultural Revolution. Beginning in Kingdom of Great Britain, Great Britain around 1760, the Industrial Revolution had spread to continental Europe and the United States by about 1840. This transition included going from craft production, hand production methods to machines; new Chemical industry, chemical manufacturing and Puddling (metallurgy), iron production processes; the increasing use of Hydropower, water power and Steam engine, steam power; the development of machine tools; and rise of the mechanisation, mechanised factory system. Output greatly increased, and the result was an unprecedented rise in population and population growth. The textile industry was the first to use modern production methods, and textiles b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biological Pump
The biological pump (or ocean carbon biological pump or marine biological carbon pump) is the ocean's biologically driven Carbon sequestration, sequestration of carbon from the atmosphere and land runoff to the ocean interior and seafloor sediments.Sigman DM & GH Haug. 2006. The biological pump in the past. In: Treatise on Geochemistry; vol. 6, (ed.). Pergamon Press, pp. 491-528 In other words, it is a biologically mediated process which results in the sequestering of carbon in the deep ocean away from the atmosphere and the land. The biological pump is the biological component of the "marine carbon pump" which contains both a physical and biological component. It is the part of the broader oceanic carbon cycle responsible for the cycling of organic matter formed mainly by phytoplankton during photosynthesis (soft-tissue pump), as well as the cycling of calcium carbonate (CaCO3) formed into shells by certain organisms such as plankton and mollusks (carbonate pump). Budget calcul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photic Zone
The photic zone (or euphotic zone, epipelagic zone, or sunlight zone) is the uppermost layer of a body of water that receives sunlight, allowing phytoplankton to perform photosynthesis. It undergoes a series of physical, chemical, and biological processes that supply nutrients into the upper water column. The photic zone is home to the majority of Aquatic ecosystem, aquatic life due to the activity (Marine primary production, primary production) of the phytoplankton. The thicknesses of the photic and euphotic zones vary with the intensity of sunlight as a function of season and latitude and with the degree of water turbidity. The bottommost, or aphotic, zone is the region of perpetual darkness that lies beneath the photic zone and includes most of the ocean waters. Photosynthesis in photic zone In the photic zone, the photosynthesis rate exceeds the respiration rate. This is due to the abundant solar energy which is used as an energy source for photosynthesis by primary produce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phytoplankton Bloom Off Argentina - November 9, 2013
Phytoplankton () are the autotrophic (self-feeding) components of the plankton community and a key part of ocean and freshwater ecosystems. The name comes from the Greek words (), meaning 'plant', and (), meaning 'wanderer' or 'drifter'. Phytoplankton obtain their energy through photosynthesis, as trees and other plants do on land. This means phytoplankton must have light from the sun, so they live in the well-lit surface layers (euphotic zone) of oceans and lakes. In comparison with terrestrial plants, phytoplankton are distributed over a larger surface area, are exposed to less seasonal variation and have markedly faster turnover rates than trees (days versus decades). As a result, phytoplankton respond rapidly on a global scale to climate variations. Phytoplankton form the base of marine and freshwater food webs and are key players in the global carbon cycle. They account for about half of global photosynthetic activity and at least half of the oxygen production, despite am ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Somali Current
The Somali Current is a cold ocean boundary current that runs along the coast of Somalia and Oman in the Western Indian Ocean and is analogous to the Gulf Stream in the Atlantic Ocean. This current is heavily influenced by the monsoons and is the only major upwelling system that occurs on a western boundary of an ocean. The water that is upwelled by the current merges with another upwelling system, creating one of the most productive ecosystems in the ocean.Mann, K.H., Lazier, J.R.N. (2006) "Dynamics of marine ecosystems: biological-physical interactions in the oceans." Oxford: Blackwell Publishing Ltd. The Somali current is characterized by seasonal changes influenced by the Southwest monsoon and the Northeast Monsoon. During the months of June to September, the warm Southwest monsoon moves the coastal waters northeastward, creating coastal upwelling. The upwelled water is carried offshore by Ekman transport and merges with water that was brought to the surface by open-ocea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Humboldt Current
The Humboldt Current, also called the Peru Current, is a cold, low-salinity ocean current that flows north along the western coast of South America.Montecino, Vivian, and Carina B. Lange. "The Humboldt Current System: Ecosystem components and processes, fisheries, and sediment studies." ''Progress in Oceanography'' 83.1 (2009): 65-79. doi:10.1016/j.pocean.2009.07.041 It is an eastern boundary current flowing in the direction of the equator, and extends offshore. The Humboldt Current is named after the German naturalist Alexander von Humboldt even though it was discovered by José de Acosta 250 years before Humboldt. In 1846, von Humboldt reported measurements of the cold-water current in his book ''Cosmos''. The current extends from southern Chile (~ 45th parallel south) to northern Peru (~ 4th parallel south) where cold, upwelled, waters intersect warm tropical waters to form the Equatorial Front. Sea surface temperatures off the coast of Peru, around 5th parallel south, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oyashio Current
The , also known as the Okhotsk Current or Kurile Current, is a cold subarctic ocean current that flows south and circulates counterclockwise in the western North Pacific Ocean. The waters of the Oyashio Current originate in the Arctic Ocean and flow southward via the Bering Sea, passing through the Bering Strait and transporting cold water from the Arctic Sea into the Pacific Ocean and the Sea of Okhotsk. It collides with the Kuroshio Current off the eastern shore of Japan to form the North Pacific Current (or Drift). The nutrient-rich Oyashio is named for its metaphorical role as the that provides for and nurtures marine organisms. Climate impact The current has an important impact on the climate of the Russian Far East, mainly in Kamchatka and Chukotka, where the northern limit of tree growth is moved south up to ten degrees compared with the latitude it can reach in inland Siberia. The waters of the Oyashio Current form probably the richest fishery in the world owing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alaska Current
The Alaska Current is a southwestern shallow warm-water current alongside the west coast of the North American continent beginning at about 48-50°N. The Alaska Current produces large clockwise eddies at two sites: west of the Haida Gwaii (" Haida Eddies") and west of Sitka, Alaska ("Sitka Eddy"). Track The Alaska current results from the northward diversion of a portion of the North Pacific Current. The North Pacific Current provides energy for the California Current and the Alaska Current. It forms a part of the Alaska Current and continues into the Alaskan Stream, which begins near Kodiak Island and flows southwestward along the Alaska Peninsula. A part of the Alaskan Stream turns southward and becomes part of the recirculation of the North Pacific Ocean Current, thus completing the loop of the Alaska Gyre. Physical properties The Gulf of Alaska coastal area includes the offshore Alaska Current, Alaskan Stream, Alaska Coastal Current and some eddies. In the eastern par ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
