1.
Diatom
–
Diatoms are a major group of algae, and are among the most common types of phytoplankton. Diatoms are unicellular, although they can form colonies in the shape of filaments or ribbons, fans, zigzags, the first diatom formally described in scientific literature, the colonial Bacillaria paradoxa, was found in 1783 by Danish naturalist Otto Friedrich Müller. Diatoms are producers within the food chain, a unique feature of diatom cells is that they are enclosed within a cell wall made of silica called a frustule. These frustules show a diversity in form, but are usually almost bilaterally symmetrical. The symmetry is not perfect since one of the valves is slightly larger than the other, fossil evidence suggests that they originated during, or before, the early Jurassic period. Only male gametes of centric diatoms are capable of movement by means of flagella, diatom communities are a popular tool for monitoring environmental conditions, past and present, and are commonly used in studies of water quality. More than 200 genera of living diatoms are known, with an estimated 100,000 extant species, diatoms are a widespread group and can be found in the oceans, in fresh water, in soils, and on damp surfaces. They dominate over phytoplankton in nutrient-rich coastal waters and during oceanic spring blooms since they can more rapidly than phytoplankton. Most live pelagically in open water, although some live as surface films at the water-sediment interface and they are especially important in oceans, where they contribute an estimated 45% of the total oceanic primary production of organic material. Spatial distribution of phytoplankton species is restricted both horizontally and vertically. Though most are microscopic, some species of diatoms can reach up to 2 mm in length, diatoms belong to a large group called the heterokonts, including both autotrophs and heterotrophs. Their yellowish-brown chloroplasts are typical of heterokonts, having four membranes, individuals usually lack flagella, but they are present in male gametes of the centric diatoms and have the usual heterokont structure, except they lack the hairs characteristic in other groups. Most diatoms are nonmotile, as their relatively dense cell walls cause them to readily sink, planktonic forms in open water usually rely on turbulent mixing of the upper layers by the wind to keep them suspended in sunlit surface waters. Some species actively regulate their buoyancy with intracellular lipids to counter sinking, a feature of diatoms is the urea cycle, which links them evolutionarily to animals. This was discovered in research carried out by Andrew Allen, Chris Bowler and their study showed that while diatoms and animals use the urea cycle for different ends, they are seen to be evolutionally linked in such a way that animals and plants are not. Diatom cells are contained within a unique cell wall known as a frustule made up of two valves called thecae, that typically overlap one another. The biogenic silica composing the wall is synthesised intracellularly by the polymerisation of silicic acid monomers. This material is extruded to the cell exterior and added to the wall
Diatom
–
Diatoms
Diatom
–
Several species of fresh-water diatoms.
Diatom
–
Selections from
Ernst Haeckel 's 1904
Kunstformen der Natur (Art Forms of Nature), showing pennate (left) and centric (right) frustules.
Diatom
2.
Autotrophic
–
An autotroph or producer, is an organism that produces complex organic compounds from simple substances present in its surroundings, generally using energy from light or inorganic chemical reactions. They are the producers in a chain, such as plants on land or contrast to heterotrophs as consumers of autotrophs). They do not need a source of energy or organic carbon. Autotrophs can reduce carbon dioxide to organic compounds for biosynthesis. Most autotrophs use water as the agent, but some can use other hydrogen compounds such as hydrogen sulfide. Some autotrophs, like plants and algae, are phototrophs. Autotrophs can be photoautotrophs or chemoautotrophs, lithotrophs use inorganic compounds, such as hydrogen sulfide, elemental sulfur, ammonium and ferrous iron, as reducing agents for biosynthesis and chemical energy storage. Photoautotrophs and lithoautotrophs use a portion of the ATP produced during photosynthesis or the oxidation of inorganic compounds to reduce NADP+ to NADPH to form organic compounds, the greek term autotroph was coined by the german botanist Albert Bernhard Frank in 1892. Some organisms rely on organic compounds as a source of carbon, such organisms are not defined as autotrophic, but rather as heterotrophic. Evidence suggests that some fungi may also obtain energy from radiation, such radiotrophic fungi were found growing inside a reactor of the Chernobyl nuclear power plant. Autotrophs are fundamental to the chains of all ecosystems in the world. They take energy from the environment in the form of sunlight or inorganic chemicals and this mechanism is called primary production. Other organisms, called heterotrophs, take in autotrophs as food to carry out functions necessary for their life. Thus, heterotrophs — all animals, almost all fungi, as well as most bacteria and protozoa — depend on autotrophs, or primary producers, for the energy, heterotrophs obtain energy by breaking down organic molecules obtained in food. Carnivorous organisms rely on autotrophs indirectly, as the nutrients obtained from their heterotroph prey come from autotrophs they have consumed, most ecosystems are supported by the autotrophic primary production of plants that capture photons initially released by the sun. Plants convert and store the energy of the photon into the bonds of simple sugars during photosynthesis. These plant sugars are polymerized for storage as long-chain carbohydrates, including other sugars, starch, when autotrophs are eaten by heterotrophs, i. e. consumers such as animals, the carbohydrates, fats, and proteins contained in them become energy sources for the heterotrophs. Proteins can be made using nitrates, sulfates, and phosphates in the soil, autotroph Chemoautotroph Lithotroph Photoautotroph Heterotroph Chemoheterotroph Lithotroph Photoheterotroph Organotroph Primary nutritional groups Heterotrophic nutrition
Autotrophic
–
Green fronds of a
maidenhair fern, a photoautotroph
Autotrophic
–
Overview of cycle between autotrophs and
heterotrophs.
Photosynthesis is the main means by which plants, algae and many bacteria produce organic compounds and oxygen from carbon dioxide and water (green arrow).
Autotrophic
–
General
Autotrophic
–
Population ecology
3.
Plankton
–
Plankton are the diverse collection of organisms that live in the water column of large bodies of water and are unable to swim against a current. They provide a source of food to many large aquatic organisms, such as fish. These organisms include bacteria, archaea, algae, protozoa and drifting or floating animals that inhabit, for example, essentially, plankton are defined by their ecological niche rather than any phylogenetic or taxonomic classification. Though many planktonic species are microscopic in size, plankton includes organisms covering a range of sizes. The name plankton is derived from the Greek adjective πλαγκτός, meaning errant and it was coined by Victor Hensen. Plankton typically flow with ocean currents, while some forms are capable of independent movement and can swim hundreds of meters vertically in a single day, their horizontal position is primarily determined by the surrounding currents. This is in contrast to nekton organisms that can swim against the ambient flow, within the plankton, holoplankton spend their entire life cycle as plankton. By contrast, meroplankton are only planktic for part of their lives, examples of meroplankton include the larvae of sea urchins, starfish, crustaceans, marine worms, and most fish. Plankton abundance and distribution are strongly dependent on such as ambient nutrient concentrations, the physical state of the water column. The study of plankton is termed planktology and an individual is referred to as a plankter. The adjective planktonic is widely used in both the scientific and popular literature, and is an accepted term. However, from the standpoint of prescriptive grammar the less commonly used planktic is more strictly the correct adjective, when deriving English words from their Greek or Latin roots the gender specific ending is normally dropped, using only the root of the word in the derivation. Among the more important groups are the diatoms, cyanobacteria, dinoflagellates and coccolithophores, zooplankton, small protozoans or metazoans that feed on other plankton and telonemia. Some of the eggs and larvae of larger animals, such as fish, crustaceans, bacterioplankton, bacteria and archaea, which play an important role in remineralising organic material down the water column. Mycoplankton, fungi and fungus-like organisms, which also are significant in nutrient cycling and this scheme divides the plankton community into broad producer, consumer and recycler groups. However, determining the level of some plankton is not straightforward. For example, although most dinoflagellates are either photosynthetic producers or heterotrophic consumers, Plankton are also often described in terms of size. Usually the following divisions are used, However, some of terms may be used with very different boundaries
Plankton
–
Photomontage of planktonic organisms
Plankton
–
Some marine
diatoms —a key
phytoplankton group
Plankton
–
An
amphipod (Hyperia macrocephala)
Plankton
–
Macroplankton: a
Janthina janthina snail (with bubble float) cast up onto a beach in
Maui
4.
Aquatic ecosystem
–
An aquatic ecosystem is an ecosystem in a body of water. Communities of organisms that are dependent on other and on their environment live in aquatic ecosystems. The two main types of ecosystems are marine ecosystems and freshwater ecosystems. Marine ecosystems cover approximately 71% of the Earths surface and contain approximately 97% of the planets water and they generate 32% of the worlds net primary production. They are distinguished from freshwater ecosystems by the presence of dissolved compounds, especially salts, approximately 85% of the dissolved materials in seawater are sodium and chlorine. Seawater has a salinity of 35 parts per thousand of water. Actual salinity varies among different marine ecosystems, marine ecosystems can be divided into many zones depending upon water depth and shoreline features. The oceanic zone is the vast open part of the ocean where animals such as whales, sharks, the benthic zone consists of substrates below water where many invertebrates live. The intertidal zone is the area between high and low tides, in this figure it is termed the littoral zone, other near-shore zones can include estuaries, salt marshes, coral reefs, lagoons and mangrove swamps. In the deep water, hydrothermal vents may occur where chemosynthetic sulfur bacteria form the base of the food web, classes of organisms found in marine ecosystems include brown algae, dinoflagellates, corals, cephalopods, echinoderms, and sharks. Fishes caught in marine ecosystems are the biggest source of commercial foods obtained from wild populations, environmental problems concerning marine ecosystems include unsustainable exploitation of marine resources, marine pollution, climate change, and building on coastal areas. Freshwater ecosystems cover 0. 78% of the Earths surface and inhabit 0. 009% of its total water and they generate nearly 3% of its net primary production. Freshwater ecosystems contain 41% of the known fish species. There are three types of freshwater ecosystems, Lentic, slow moving water, including pools, ponds. Lotic, faster moving water, for example streams and rivers, wetlands, areas where the soil is saturated or inundated for at least part of the time. Lake ecosystems can be divided into zones, one common system divides lakes into three zones. The first, the zone, is the shallow zone near the shore. This is where rooted wetland plants occur, the offshore is divided into two further zones, an open water zone and a deep water zone
Aquatic ecosystem
–
An
estuary mouth and coastal waters, part of an aquatic ecosystem
Aquatic ecosystem
–
Freshwater ecosystem.
Aquatic ecosystem
–
Marine
Aquatic ecosystem
5.
Greek language
–
Greek is an independent branch of the Indo-European family of languages, native to Greece and other parts of the Eastern Mediterranean. It has the longest documented history of any living language, spanning 34 centuries of written records and its writing system has been the Greek alphabet for the major part of its history, other systems, such as Linear B and the Cypriot syllabary, were used previously. The alphabet arose from the Phoenician script and was in turn the basis of the Latin, Cyrillic, Armenian, Coptic, Gothic and many other writing systems. Together with the Latin texts and traditions of the Roman world, during antiquity, Greek was a widely spoken lingua franca in the Mediterranean world and many places beyond. It would eventually become the official parlance of the Byzantine Empire, the language is spoken by at least 13.2 million people today in Greece, Cyprus, Italy, Albania, Turkey, and the Greek diaspora. Greek roots are used to coin new words for other languages, Greek. Greek has been spoken in the Balkan peninsula since around the 3rd millennium BC, the earliest written evidence is a Linear B clay tablet found in Messenia that dates to between 1450 and 1350 BC, making Greek the worlds oldest recorded living language. Among the Indo-European languages, its date of earliest written attestation is matched only by the now extinct Anatolian languages, the Greek language is conventionally divided into the following periods, Proto-Greek, the unrecorded but assumed last ancestor of all known varieties of Greek. The unity of Proto-Greek would have ended as Hellenic migrants entered the Greek peninsula sometime in the Neolithic era or the Bronze Age, Mycenaean Greek, the language of the Mycenaean civilisation. It is recorded in the Linear B script on tablets dating from the 15th century BC onwards, Ancient Greek, in its various dialects, the language of the Archaic and Classical periods of the ancient Greek civilisation. It was widely known throughout the Roman Empire, after the Roman conquest of Greece, an unofficial bilingualism of Greek and Latin was established in the city of Rome and Koine Greek became a first or second language in the Roman Empire. The origin of Christianity can also be traced through Koine Greek, Medieval Greek, also known as Byzantine Greek, the continuation of Koine Greek in Byzantine Greece, up to the demise of the Byzantine Empire in the 15th century. Much of the written Greek that was used as the language of the Byzantine Empire was an eclectic middle-ground variety based on the tradition of written Koine. Modern Greek, Stemming from Medieval Greek, Modern Greek usages can be traced in the Byzantine period and it is the language used by the modern Greeks, and, apart from Standard Modern Greek, there are several dialects of it. In the modern era, the Greek language entered a state of diglossia, the historical unity and continuing identity between the various stages of the Greek language is often emphasised. Greek speakers today still tend to regard literary works of ancient Greek as part of their own rather than a foreign language and it is also often stated that the historical changes have been relatively slight compared with some other languages. According to one estimation, Homeric Greek is probably closer to demotic than 12-century Middle English is to modern spoken English, Greek is spoken by about 13 million people, mainly in Greece, Albania and Cyprus, but also worldwide by the large Greek diaspora. Greek is the language of Greece, where it is spoken by almost the entire population
Greek language
–
Idealized portrayal of
Homer
Greek language
–
regions where Greek is the official language
Greek language
–
Greek language road sign, A27 Motorway, Greece
6.
Plant
–
Plants are mainly multicellular, predominantly photosynthetic eukaryotes of the kingdom Plantae. The term is generally limited to the green plants, which form an unranked clade Viridiplantae. This includes the plants, conifers and other gymnosperms, ferns, clubmosses, hornworts, liverworts, mosses and the green algae. Green plants have cell walls containing cellulose and obtain most of their energy from sunlight via photosynthesis by primary chloroplasts and their chloroplasts contain chlorophylls a and b, which gives them their green color. Some plants are parasitic and have lost the ability to produce amounts of chlorophyll or to photosynthesize. Plants are characterized by sexual reproduction and alternation of generations, although reproduction is also common. There are about 300–315 thousand species of plants, of which the great majority, green plants provide most of the worlds molecular oxygen and are the basis of most of Earths ecologies, especially on land. Plants that produce grains, fruits and vegetables form humankinds basic foodstuffs, Plants play many roles in culture. They are used as ornaments and, until recently and in variety, they have served as the source of most medicines. The scientific study of plants is known as botany, a branch of biology, Plants are one of the two groups into which all living things were traditionally divided, the other is animals. The division goes back at least as far as Aristotle, who distinguished between plants, which generally do not move, and animals, which often are mobile to catch their food. Much later, when Linnaeus created the basis of the system of scientific classification. Since then, it has become clear that the plant kingdom as originally defined included several unrelated groups, however, these organisms are still often considered plants, particularly in popular contexts. When the name Plantae or plant is applied to a group of organisms or taxon. The evolutionary history of plants is not yet settled. Those which have been called plants are in bold, the way in which the groups of green algae are combined and named varies considerably between authors. Algae comprise several different groups of organisms which produce energy through photosynthesis, most conspicuous among the algae are the seaweeds, multicellular algae that may roughly resemble land plants, but are classified among the brown, red and green algae. Each of these groups also includes various microscopic and single-celled organisms
Plant
–
Green algae from
Ernst Haeckel 's
Kunstformen der Natur, 1904.
Plant
–
Had'n
Plant
–
Dicksonia antarctica, a species of
tree fern
Plant
–
A petrified log in
Petrified Forest National Park.
7.
Naked eye
–
Naked eye, also called bare eye or unaided eye, is the practice of engaging in visual perception unaided by a magnifying or light-collecting optical device, such as a telescope or microscope. Vision corrected to normal acuity using corrective lenses is considered naked, in astronomy, the naked eye may be used to observe events that can be viewed without equipment, such as an astronomical conjunction, the passage of a comet, or a meteor shower. Sky lore and various tests demonstrate a wealth of phenomena that can be seen with the unaided eye. The basic accuracies of the eye are, Quick autofocus from distances of 25 cm to 50 cm to infinity. Angular resolution, about 1 arcminute, approximately 0. 02° or 0.0003 radians, field of view, simultaneous visual perception in an area of about 160° × 175°. Faint stars up to +8 magnitude under a dark sky. Photometry to ±10% or 1% of intensity – in a range between night and day of 1,10,000,000,000, symmetries of 10–20, see the measurements of Tycho Brahe and the Egyptians. Even a few hundred kilometers away from an area where the sky can appear to be very dark. For most people, these are likely to be the best observing conditions within their reach, under such typical dark sky conditions, the naked eye can see stars with an apparent magnitude up to +6m. Under perfect dark sky conditions where all light pollution is absent, the angular resolution of the naked eye is about 1′, however, some people have sharper vision than that. There is anecdotal evidence that people had seen the Galilean moons of Jupiter before telescopes were invented, Uranus, when discovered in 1781, was the first planet discovered using technology rather than being spotted by the naked eye. In practice, the extinction and dust reduces this number somewhat. In the center of a city, where the limiting magnitude due to extreme amounts of light pollution can be +4m or less. Colors can be seen but this is limited by the fact that the eye uses rods instead of cones to view fainter stars, the visibility of diffuse objects such as star clusters and galaxies is much more strongly affected by light pollution than is that of planets and stars. Under typical dark conditions only a few objects are visible. The Triangulum Galaxy is a difficult averted vision object and only visible at all if it is higher than 50° in the sky, the globular clusters M3 in Canes Venatici and M92 in Hercules are also visible with the naked eye under such conditions. Under really dark sky conditions, however, M33 is easy to see, many other Messier objects are also visible under such conditions. The most distant objects that have seen by the naked eye are nearby bright galaxies such as Centaurus A, Bodes Galaxy, Sculptor Galaxy
Naked eye
–
The naked eye
Naked eye
–
In addition to its arsenal of telescopes,
Cerro Paranal is used for naked eye astronomical observations. Credit
ESO.
Naked eye
–
The
Moon and the Arc of the
Milky Way as seen on
Chajnantor plateau.
Naked eye
–
Milky Way visible on the
Very Large Telescope. It is a proof of the quality of the skies above
Paranal Observatory.
8.
Chlorophyll
–
Chlorophyll is any of several closely related green pigments found in cyanobacteria and the chloroplasts of algae and plants. Its name is derived from the Greek words χλωρός, chloros and φύλλον, chlorophyll is essential in photosynthesis, allowing plants to absorb energy from light. Chlorophyll absorbs light most strongly in the portion of the electromagnetic spectrum. Conversely, it is a poor absorber of green and near-green portions of the spectrum, chlorophyll molecules are specifically arranged in and around photosystems that are embedded in the thylakoid membranes of chloroplasts. Two types of chlorophyll exist in the photosystems of green plants, chlorophyll was first isolated and named by Joseph Bienaimé Caventou and Pierre Joseph Pelletier in 1817. Chlorophyll is vital for photosynthesis, which plants to absorb energy from light. Chlorophyll molecules are arranged in and around photosystems that are embedded in the thylakoid membranes of chloroplasts. In these complexes, chlorophyll serves two primary functions, the two currently accepted photosystem units are photosystem II and photosystem I, which have their own distinct reaction centres, named P680 and P700, respectively. These centres are named after the wavelength of their red-peak absorption maximum, the identity, function and spectral properties of the types of chlorophyll in each photosystem are distinct and determined by each other and the protein structure surrounding them. Once extracted from the protein into a solvent, these chlorophyll pigments can be separated into chlorophyll a, the function of the reaction center of chlorophyll is to absorb light energy and transfer it to other parts of the photosystem. The absorbed energy of the photon is transferred to an electron in a process called charge separation, the removal of the electron from the chlorophyll is an oxidation reaction. The chlorophyll donates the high energy electron to a series of molecular intermediates called a transport chain. The charged reaction center of chlorophyll is reduced back to its ground state by accepting an electron stripped from water. The electron that reduces P680+ ultimately comes from the oxidation of water into O2 and this reaction is how photosynthetic organisms such as plants produce O2 gas, and is the source for practically all the O2 in Earths atmosphere. Electron transfer reactions in the membranes are complex, however. NADPH is an agent used to reduce CO2 into sugars as well as other biosynthetic reactions. Thus, the other chlorophylls in the photosystem and antenna pigment proteins all cooperatively absorb, besides chlorophyll a, there are other pigments, called accessory pigments, which occur in these pigment–protein antenna complexes. Chlorophyll is a pigment, which is structurally similar to
Chlorophyll
–
Chlorophyll gives leaves their green color and absorbs light that is used in photosynthesis.
Chlorophyll
Chlorophyll
–
Chlorophyll is found in high concentrations in
chloroplasts of plant cells.
9.
Xanthophyll
–
Xanthophylls are yellow pigments that occur widely in nature and form one of two major divisions of the carotenoid group, the other division is formed by the carotenes. The name is from Greek xanthos and phyllon, due to their formation of the band seen in early chromatography of leaf pigments. The molecular structure of xanthophylls is similar to that of carotenes, xanthophylls contain their oxygen either as hydroxyl groups and/or as pairs of hydrogen atoms that are substituted by oxygen atoms acting as a bridge. For this reason, they are more polar than the purely hydrocarbon carotenes, typically, carotenes are more orange in color than xanthophylls. The xanthophylls found in the bodies of animals, and in animal products, are ultimately derived from plant sources in the diet. For example, the color of chicken egg yolks, fat. These xanthophylls protect the eye from ionizing blue and ultraviolet light and these two specific xanthophylls do not function in the mechanism of sight, since they cannot be converted to retinal. Their arrangement is believed to be the cause of Haidingers brush, the group of xanthophylls includes lutein, zeaxanthin, neoxanthin, violaxanthin, flavoxanthin, and α- and β-cryptoxanthin. The latter compound is the only known xanthophyll to contain a beta-ionone ring, even then, it is a vitamin only for plant-eating mammals that possess the enzyme to make retinal from carotenoids that contain beta-ionone. In species other than mammals, certain xanthophylls may be converted to hydroxylated retinal-analogues that function directly in vision, the xanthophyll cycle involves the enzymatic removal of epoxy groups from xanthophylls to create so-called de-epoxidised xanthophylls. Non-photochemical quenching is one of the ways of protecting against photoinhibition. In higher plants, there are three carotenoid pigments that are active in the cycle, violaxanthin, antheraxanthin, and zeaxanthin. This conversion of violaxanthin to zeaxanthin is done by the enzyme violaxanthin de-epoxidase, in diatoms and dinoflagellates, the xanthophyll cycle consists of the pigment diadinoxanthin, which is transformed into diatoxanthin or dinoxanthin under high-light conditions. Xanthophylls are found in all young leaves and in etiolated leaves, examples of other rich sources include papaya, peaches, prunes, and squash, which contain lutein diesters. Demmig-Adams, B & W. W. Adams,2006, photoprotection in an ecological context, the remarkable complexity of thermal energy dissipation, New Phytologist,172, 11–21. Xanthophylls at the US National Library of Medicine Medical Subject Headings
Xanthophyll
–
The color of an egg yolk is from the xanthophyll carotenoids lutein and zeaxanthin
Xanthophyll
–
Thin layer chromatography is used to separate components of a plant extract, illustrating the experiment with plant pigments that gave chromatography its name. Plant xanthophylls form the bright yellow band next to the green
10.
Oyashio Current
–
Oyashio, also known as Oya Siwo, Okhotsk or the Kurile current, is a cold subarctic ocean current that flows south and circulates counterclockwise in the western North Pacific Ocean. It collides with the Kuroshio Current off the shore of Japan to form the North Pacific Current. The nutrient-rich Oyashio is named for its role as the parent that provides for. However, the Oyashio Current also causes Vladivostok to be the most equatorward port to seasonally freeze, nonetheless, this has relatively little effect on the fish yield through the Sea of Okhotsk, because the large tides mean freezing does not occur so easily. During glacial periods, when sea level exposed the Bering land bridge. The level of cooling with the onset of glacial conditions was much less than in areas of the Earth at similar latitudes. Ocean current Oceanic gyres Physical oceanography Japanese destroyer Oyashio, the Imperial Japanese Navy destroyer named after the current, taylor and Francis, ISBN 90-5410-706-5, pp 367–8. Regional Definition page for the Oyashio Current, UNEP Global International Waters Assessment, accessed 2 July 2010
Oyashio Current
–
The Oyashio Current colliding with the
Kuroshio Current near
Hokkaido. When two currents collide, they create
eddies.
Phytoplankton growing in the surface waters become concentrated along the boundaries of these eddies, tracing out the motions of the water.
11.
Kuroshio Current
–
The Kuroshio is a north-flowing ocean current on the west side of the North Pacific Ocean. It is similar to the Gulf Stream in the North Atlantic and is part of the North Pacific ocean gyre, like the Gulf stream, it is a strong western boundary current. It begins off the east coast of Luzon, Philippines, Taiwan and flows northeastward past Japan and it is analogous to the Gulf Stream in the Atlantic Ocean, transporting warm, tropical water northward toward the polar region. It is sometimes known as the Black Stream — the English translation of kuroshio, the path of Kuroshio south of Japan is reported every day. Its counterparts are the North Pacific Current to the north, the California Current to the east, the warm waters of the Kuroshio Current sustain the coral reefs of Japan, the northernmost coral reefs in the world. The branch into the Sea of Japan is called Tsushima Current, western boundary currents transport organisms long distances rapidly and a variety of commercially important marine organisms migrate in these currents in the course of completing their lives. Subtropical gyres occupy a fraction of the worlds ocean and are more productive than originally thought. In addition, their fixation of carbon dioxide is an important factor in the budget for carbon dioxide in the atmosphere. Satellite images of the Kuroshio Current illustrate how the current path meanders, eddies retain their unique form for several months and have their own biological characteristics that depend on where they form. The eddies size and strength decline with distance from major ocean currents, the amount of energy decreases from the rings associated with the major currents and down to eddies remote from those currents. Cyclonic eddies have the potential to cause upwelling that would affect the global primary-production budget, upwelling brings cold, nutrient-rich water to the surface resulting in an increase in productivity. The biological consequences for fish populations that inhabit the shelf are quite large. The Kuroshio is a warm current—24 °C annual average sea-surface temperature—about 100 kilometres wide, the coastal areas are highly productive and the maximum chlorophyll value is found around 100 metres depth. There are indications that eddies contribute to the preservation and survival of fish larvae transported by the Kuroshio, plankton biomass fluctuates yearly and is typically highest in the eddy area of the Kuroshio’s edge. Warm-core rings are not known for having high productivity, however, the biology of the warm-core rings from the Kuroshio Current show results of productivity equally distributed throughout for a couple of reasons. One is upwelling at the periphery, the other is the convective mixing caused by the cooling of water as the ring moves north of the current. The thermostad is the mixed layer that has discrete boundaries. Within this layer, nutrient-rich water is brought to the surface, there are many complex interactions with the warm-core ring and thus lifetime productivity is not very different from the surrounding shelf water
Kuroshio Current
–
The
Oyashio Current colliding with the Kuroshio Current near
Hokkaido. When two currents collide, they create
eddies.
Phytoplankton growing in the surface waters become concentrated along the boundaries of these eddies, tracing out the motions of the water.
Kuroshio Current
–
The Kuroshio Current is the west side of the clockwise North Pacific
ocean gyre
12.
Eddies
–
In fluid dynamics, an eddy is the swirling of a fluid and the reverse current created when the fluid is in a turbulent flow regime. The moving fluid creates a space devoid of downstream-flowing fluid on the side of the object. This phenomenon is naturally observed behind large emergent rocks in swift-flowing rivers, the propensity of a fluid to swirl is used to promote good fuel/air mixing in internal combustion engines. In fluid mechanics and transport phenomena, an eddy is not a property of the fluid, turbulent flow is defined as the flow in which the systems inertial forces are dominant over the viscous forces. This phenomena is described by Reynolds number, a number used to determine when turbulent flow will occur. Conceptually, the Reynolds number is the ratio between inertial forces and viscous forces, blood flow in straight sections of the arterial tree are typically laminar, but branches and curvatures in the system cause turbulent flow. Lift and drag properties of golf balls are customized by the manipulation of dimples along the surface of the ball, oceanic and atmospheric currents transfer particles, debris, and organisms all across the globe. Eddy formations circulate trash and other pollutants into concentrated areas which researchers are tracking to improve clean-up, mesoscale ocean eddies play crucial rolls in transferring heat poleward, as well as maintaining heat gradients at different depths. Eddies are common in the ocean, and range in diameter from centimeters to hundreds of kilometers, the smallest scale eddies may last for a matter of seconds, while the larger features may persist for months to years. Eddies which are between about 10 and 500 km in diameter and persist for periods of days to months are known in oceanography as mesoscale eddies. Mesoscale eddies can be split into two categories, static eddies, caused by flow around an obstacle, and transient eddies, when the ocean contains a sea surface height gradient this creates a jet or current, such as the Antarctic Circumpolar Current. This current as part of an unstable system meanders and creates eddies. Mesoscale ocean eddies are characterized by currents which flow in a circular motion around the center of the eddy. The sense of rotation of these currents may either be cyclonic or anticyclonic, oceanic eddies are also usually made of water masses that are different from those outside of the eddy. That is, the water within an eddy usually has different temperature, there is a direct link between the water mass properties of an eddy and its rotation. Warm eddies rotate anti-cyclonically, while cold eddies rotate cyclonically, because eddies may have a vigorous circulation associated with them, they are of concern to naval and commercial operations at sea. Further, because eddies transport anomalously warm or cold water as they move, they have an important influence on heat transport in certain parts of the ocean
Eddies
–
Downwind of obstacles, in this case, the
Madeira and the
Canary Islands off the west African coast, eddies create turbulent patterns called vortex streets.
Eddies
–
When two currents (in this case the
Oyashio and
Kuroshio currents) collide, they create eddies.
Phytoplankton become concentrated along the boundaries of these eddies, tracing out the motions of the water.
13.
Algal bloom
–
An algal bloom is a rapid increase or accumulation in the population of algae in freshwater or marine water systems, and is recognized by the discoloration in the water from their pigments. Cyanobacteria were mistaken for algae in the past, so cyanobacterial blooms are also called algal blooms. Blooms which can injure animals or the ecology are called harmful algal blooms, since algae is a broad term including organisms of widely varying sizes, growth rates and nutrient requirements, there is no officially recognized threshold level as to what is defined as a bloom. For some species, algae can be considered to be blooming at concentrations reaching millions of cells per milliliter, bright green blooms in freshwater systems are frequently a result of cyanobacteria such as Microcystis. Blooms may also consist of macroalgal species and these blooms are recognizable by large blades of algae that may wash up onto the shoreline. Such blooms often take on a red or brown hue and are known colloquially as red tides, freshwater algal blooms are the result of an excess of nutrients, particularly some phosphates. The excess of nutrients may originate from fertilizers that are applied to land for agricultural or recreational purposes and they may also originate from household cleaning products containing phosphorus. These nutrients can then enter watersheds through water runoff, excess carbon and nitrogen have also been suspected as causes. Presence of residual sodium carbonate acts as catalyst for the algae to bloom by providing dissolved carbon dioxide for enhanced photosynthesis in the presence of nutrients, when phosphates are introduced into water systems, higher concentrations cause increased growth of algae and plants. Algae tend to very quickly under high nutrient availability, but each alga is short-lived. The decay process consumes dissolved oxygen in the water, resulting in hypoxic conditions, without sufficient dissolved oxygen in the water, animals and plants may die off in large numbers. Use of an Olszewski tube can help combat problems with hypolimnetic withdrawal. Blooms may be observed in freshwater aquariums when fish are overfed and these are generally harmful for fish, and the situation can be corrected by changing the water in the tank and then reducing the amount of food given. A harmful algal bloom is a bloom that causes negative impacts to other organisms via production of natural toxins, mechanical damage to other organisms. HABs are often associated with large-scale marine mortality events and have associated with various types of shellfish poisonings. In studies at the population level bloom coverage has been related to the risk of non-alcoholic liver disease death. In the marine environment, single-celled, microscopic, plant-like organisms naturally occur in the surface layer of any body of water. These organisms, referred to as phytoplankton or microalgae, form the base of the food web upon which all other marine organisms depend
Algal bloom
–
Taken in October 2011, the worst algae bloom that
Lake Erie has experienced in decades. Record torrential spring rains washed fertilizer into the lake, promoting the growth of
microcystin producing
cyanobacteria blooms.
Algal bloom
–
Algal blooms can present problems for
ecosystems and human society.
Algal bloom
–
An algae bloom off the southern coast of
Devon and
Cornwall in England, in 1999
Algal bloom
–
Satellite image of
phytoplankton swirling around the
Swedish island of
Gotland in the
Baltic Sea, in 2005
14.
Photosynthesis
–
Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that can later be released to fuel the organisms activities. In most cases, oxygen is released as a waste product. Most plants, most algae, and cyanobacteria perform photosynthesis, such organisms are called photoautotrophs, in plants, these proteins are held inside organelles called chloroplasts, which are most abundant in leaf cells, while in bacteria they are embedded in the plasma membrane. In these light-dependent reactions, some energy is used to strip electrons from suitable substances, such as water, in the Calvin cycle, atmospheric carbon dioxide is incorporated into already existing organic carbon compounds, such as ribulose bisphosphate. Using the ATP and NADPH produced by the light-dependent reactions, the compounds are then reduced and removed to form further carbohydrates. Cyanobacteria appeared later, the oxygen they produced contributed directly to the oxygenation of the Earth. Today, the rate of energy capture by photosynthesis globally is approximately 130 terawatts. Photosynthetic organisms also convert around 100–115 thousand million tonnes of carbon into biomass per year. Photosynthetic organisms are photoautotrophs, which means that they are able to synthesize food directly from carbon dioxide, however, not all organisms that use light as a source of energy carry out photosynthesis, photoheterotrophs use organic compounds, rather than carbon dioxide, as a source of carbon. In plants, algae, and cyanobacteria, photosynthesis releases oxygen and this is called oxygenic photosynthesis and is by far the most common type of photosynthesis used by living organisms. Although there are differences between oxygenic photosynthesis in plants, algae, and cyanobacteria, the overall process is quite similar in these organisms. There are also varieties of anoxygenic photosynthesis, used mostly by certain types of bacteria. Carbon dioxide is converted into sugars in a process called carbon fixation, photosynthesis provides the energy in the form of free electrons that are used to split carbon from carbon dioxide that is then used to fix that carbon once again as carbohydrate. Carbon fixation is a redox reaction, so photosynthesis supplies the energy that drives both process. In the first stage, light-dependent reactions or light reactions capture the energy of light and use it to make the energy-storage molecules ATP, during the second stage, the light-independent reactions use these products to capture and reduce carbon dioxide. Most organisms that utilize oxygenic photosynthesis use visible light for the light-dependent reactions, some organisms employ even more radical variants of photosynthesis. Some archea use a method that employs a pigment similar to those used for vision in animals. The bacteriorhodopsin changes its configuration in response to sunlight, acting as a proton pump and this produces a proton gradient more directly, which is then converted to chemical energy
Photosynthesis
–
Composite image showing the global distribution of photosynthesis, including both oceanic
phytoplankton and terrestrial
vegetation. Dark red and blue-green indicate regions of high photosynthetic activity in ocean and land respectively.
Photosynthesis
–
Schematic of photosynthesis in plants. The carbohydrates produced are stored in or used by the plant.
Photosynthesis
–
Plant cells with visible chloroplasts (from a moss,
Plagiomnium affine)
Photosynthesis
–
Melvin Calvin works in his photosynthesis laboratory.
15.
Primary production
–
In ecology, primary production is the synthesis of organic compounds from atmospheric or aqueous carbon dioxide. Almost all life on Earth relies directly or indirectly on primary production, the organisms responsible for primary production are known as primary producers or autotrophs, and form the base of the food chain. In terrestrial ecoregions, these are mainly plants, while in aquatic ecoregions algae predominate in this role, ecologists distinguish primary production as either net or gross, the former accounting for losses to processes such as cellular respiration, the latter not. Primary production is the production of energy in organic compounds by living organisms. The main source of energy is sunlight but a minute fraction of primary production is driven by lithotrophic organisms using the chemical energy of inorganic molecules. Regardless of its source, this energy is used to complex organic molecules from simpler inorganic compounds such as carbon dioxide. Consumption of primary producers by heterotrophic organisms, such as animals, then transfers these organic molecules up the food web, gross primary production is the amount of chemical energy as biomass that primary producers create in a given length of time. Some fraction of this energy is used by primary producers for cellular respiration. The remaining fixed energy is referred to as net primary production, some net primary production goes toward growth and reproduction of primary producers, while some is consumed by herbivores. Both gross and net primary production are in units of mass per area per unit time interval. In terrestrial ecosystems, mass of carbon per area per year is most often used as the unit of measurement. On the land, almost all production is now performed by vascular plants, with a small fraction coming from algae and non-vascular plants such as mosses. Before the evolution of plants, non-vascular plants likely played a more significant role. Primary production on land is a function of many factors, but principally local hydrology, while plants cover much of the Earths surface, they are strongly curtailed wherever temperatures are too extreme or where necessary plant resources are limiting, such as deserts or polar regions. Water is consumed in plants by the processes of photosynthesis and transpiration, the latter process is driven by the evaporation of water from the leaves of plants. Transpiration allows plants to transport water and mineral nutrients from the soil to growth regions, diffusion of water vapour out of a leaf, the force that drives transpiration, is regulated by structures known as stomata. These structure also regulate the diffusion of carbon dioxide from the atmosphere into the leaf, certain plants use alternative forms of photosynthesis, called Crassulacean acid metabolism and C4. In a reversal of the pattern on land, in the oceans, almost all photosynthesis is performed by algae, with a small fraction contributed by vascular plants, algae encompass a diverse range of organisms, ranging from single floating cells to attached seaweeds
Primary production
–
Global oceanic and terrestrial photoautotroph abundance, from September 1997 to August 2000. As an estimate of
autotroph biomass, it is only a rough indicator of primary production potential, and not an actual estimate of it. Provided by the
SeaWiFS Project,
NASA /
Goddard Space Flight Center and
ORBIMAGE.
Primary production
–
An
oak tree; a typical modern, terrestrial autotroph
Primary production
–
Marine
diatoms; an example of
planktonic microalgae
Primary production
–
A
kelp forest; an example of attached
macroalgae
16.
Organic compounds
–
An organic compound is virtually any chemical compound that contains carbon, although a consensus definition remains elusive and likely arbitrary. Organic compounds are rare terrestrially, but of importance because all known life is based on organic compounds. The most basic petrochemicals are considered the building blocks of organic chemistry, for historical reasons discussed below, a few types of carbon-containing compounds, such as carbides, carbonates, simple oxides of carbon, and cyanides are considered inorganic. The distinction between organic and inorganic compounds, while useful in organizing the vast subject of chemistry. Organic chemistry is the science concerned with all aspects of organic compounds, Organic synthesis is the methodology of their preparation. The word organic is historical, dating to the 1st century, for many centuries, Western alchemists believed in vitalism. This is the theory that certain compounds could be synthesized only from their classical elements—earth, water, air, vitalism taught that these organic compounds were fundamentally different from the inorganic compounds that could be obtained from the elements by chemical manipulation. Vitalism survived for a while even after the rise of modern atomic theory and it first came under question in 1824, when Friedrich Wöhler synthesized oxalic acid, a compound known to occur only in living organisms, from cyanogen. A more decisive experiment was Wöhlers 1828 synthesis of urea from the inorganic salts potassium cyanate, urea had long been considered an organic compound, as it was known to occur only in the urine of living organisms. Wöhlers experiments were followed by others, in which increasingly complex organic substances were produced from inorganic ones without the involvement of any living organism. Even though vitalism has been discredited, scientific nomenclature retains the distinction between organic and inorganic compounds, still, even the broadest definition requires excluding alloys that contain carbon, including steel. The C-H definition excludes compounds that are considered organic, neither urea nor oxalic acid is organic by this definition, yet they were two key compounds in the vitalism debate. The IUPAC Blue Book on organic nomenclature specifically mentions urea and oxalic acid, other compounds lacking C-H bonds but traditionally considered organic include benzenehexol, mesoxalic acid, and carbon tetrachloride. Mellitic acid, which contains no C-H bonds, is considered an organic substance in Martian soil. The C-H bond-only rule also leads to somewhat arbitrary divisions in sets of carbon-fluorine compounds, for example, CF4 would be considered by this rule to be inorganic, whereas CF3H would be organic. Organic compounds may be classified in a variety of ways, one major distinction is between natural and synthetic compounds. Another distinction, based on the size of organic compounds, distinguishes between small molecules and polymers, natural compounds refer to those that are produced by plants or animals. Many of these are extracted from natural sources because they would be more expensive to produce artificially
Organic compounds
–
Methane is one of the simplest organic compounds
17.
Food web
–
A food web is the natural interconnection of food chains and a graphical representation of what-eats-what in an ecological community. Another name for food web is a consumer-resource system, ecologists can broadly lump all life forms into one of two categories called trophic levels, 1) the autotrophs, and 2) the heterotrophs. To maintain their bodies, grow, develop, and to reproduce, autotrophs produce organic matter from inorganic substances and these chemical reactions require energy, which mainly comes from the sun and largely by photosynthesis, although a very small amount comes from hydrothermal vents and hot springs. The linkages in a food web illustrate the feeding pathways, such as where heterotrophs obtain organic matter by feeding on autotrophs, the food web is a simplified illustration of the various methods of feeding that links an ecosystem into a unified system of exchange. There are different kinds of feeding relations that can be divided into herbivory, carnivory, scavenging. Some of the organic matter eaten by heterotrophs, such as sugars, autotrophs and heterotrophs come in all sizes, from microscopic to many tonnes - from cyanobacteria to giant redwoods, and from viruses and bdellovibrio to blue whales. Charles Elton pioneered the concept of cycles, food chains. Elton organized species into groups, which was the basis for Raymond Lindemans classic. Lindeman emphasized the important role of organisms in a trophic system of classification. Even earlier, in 1768 John Bruckner described nature as one continued web of life, ecologists use these simplifications in quantitative models of trophic or consumer-resource systems dynamics. Using these models they can measure and test for generalized patterns in the structure of food web networks. Ecologists have identified non-random properties in the structure of food webs. Published examples that are used in analysis are of variable quality with omissions. However, the number of studies on community webs is on the rise. Scaling laws, for example, predict a relationship between the topology of food web predator-prey linkages and levels of species richness, links in food webs map the feeding connections in an ecological community. Food cycle is a term that is synonymous with food web. Ecologists can broadly group all life forms into one of two layers, the autotrophs and the heterotrophs. Autotrophs produce more energy, either chemically without the suns energy or by capturing the suns energy in photosynthesis
Food web
–
A
freshwater aquatic and
terrestrial food web
Food web
–
A simplified food web illustrating a three trophic food chain (producers-herbivores-carnivores) linked to decomposers. The movement of mineral nutrients is cyclic, whereas the movement of energy is unidirectional and noncyclic. Trophic species are encircled as nodes and arrows depict the links.
Food web
Food web
18.
Energy
–
In physics, energy is the property that must be transferred to an object in order to perform work on – or to heat – the object, and can be converted in form, but not created or destroyed. The SI unit of energy is the joule, which is the transferred to an object by the mechanical work of moving it a distance of 1 metre against a force of 1 newton. Mass and energy are closely related, for example, with a sensitive enough scale, one could measure an increase in mass after heating an object. Living organisms require available energy to stay alive, such as the humans get from food. Civilisation gets the energy it needs from energy resources such as fuels, nuclear fuel. The processes of Earths climate and ecosystem are driven by the radiant energy Earth receives from the sun, the total energy of a system can be subdivided and classified in various ways. It may also be convenient to distinguish gravitational energy, thermal energy, several types of energy, electric energy. Many of these overlap, for instance, thermal energy usually consists partly of kinetic. Some types of energy are a mix of both potential and kinetic energy. An example is energy which is the sum of kinetic. Whenever physical scientists discover that a phenomenon appears to violate the law of energy conservation. Heat and work are special cases in that they are not properties of systems, in general we cannot measure how much heat or work are present in an object, but rather only how much energy is transferred among objects in certain ways during the occurrence of a given process. Heat and work are measured as positive or negative depending on which side of the transfer we view them from, the distinctions between different kinds of energy is not always clear-cut. In contrast to the definition, energeia was a qualitative philosophical concept, broad enough to include ideas such as happiness. The modern analog of this property, kinetic energy, differs from vis viva only by a factor of two, in 1807, Thomas Young was possibly the first to use the term energy instead of vis viva, in its modern sense. Gustave-Gaspard Coriolis described kinetic energy in 1829 in its modern sense, the law of conservation of energy was also first postulated in the early 19th century, and applies to any isolated system. It was argued for years whether heat was a physical substance, dubbed the caloric, or merely a physical quantity. In 1845 James Prescott Joule discovered the link between mechanical work and the generation of heat and these developments led to the theory of conservation of energy, formalized largely by William Thomson as the field of thermodynamics
Energy
–
In a typical
lightning strike, 500
megajoules of
electric potential energy is converted into the same amount of energy in other forms, mostly
light energy,
sound energy and
thermal energy.
Energy
–
Thermal energy is energy of microscopic constituents of matter, which may include both
kinetic and
potential energy.
Energy
–
Thomas Young – the first to use the term "energy" in the modern sense.
Energy
–
A
Turbo generator transforms the energy of pressurised steam into electrical energy
19.
Photic zone
–
The photic zone, euphotic zone, or sunlight or zone is the depth of the water in a lake or ocean that is exposed to such intensity of sunlight which designates compensation point, i. e. It extends from the surface down to a depth where light intensity falls to one percent of that at the surface, accordingly, its thickness depends on the extent of light attenuation in the water column. Typical euphotic depths vary from only a few centimetres in highly turbid eutrophic lakes and it also varies with seasonal changes in turbidity. About 90% of all marine life lives in the photic zone, a small amount of primary production is generated deep in the abyssal zone around the hydrothermal vents which exist along some mid-oceanic ridges. The zone which extends from the base of the zone to about 200 metres is sometimes called the disphotic zone. While there is light, it is insufficient for photosynthesis. The euphotic zone together with the disphotic zone coincides with the epipelagic zone, the bottommost zone, below the euphotic zone, is called the aphotic zone. Most deep ocean waters belong to this zone, the transparency of the water, which determines the depth of the photic zone, is measured simply with a Secchi disk. It may also be measured with a photometer lowered into the water, electromagnetic absorption by water Epipelagic fish
Photic zone
–
General
Photic zone
–
Marine
20.
Ocean
–
An ocean is a body of saline water that composes much of a planets hydrosphere. On Earth, an ocean is one of the major divisions of the World Ocean. These are, in descending order by area, the Pacific, Atlantic, Indian, Southern, the word sea is often used interchangeably with ocean in American English but, strictly speaking, a sea is a body of saline water partly or fully enclosed by land. The ocean contains 97% of Earths water, and oceanographers have stated that less than 5% of the World Ocean has been explored, the total volume is approximately 1.35 billion cubic kilometers with an average depth of nearly 3,700 meters. As the world ocean is the component of Earths hydrosphere, it is integral to all known life, forms part of the carbon cycle. The world ocean is the habitat of 230,000 known species, but because much of it is unexplored, the origin of Earths oceans remains unknown, oceans are thought to have formed in the Hadean period and may have been the impetus for the emergence of life. Extraterrestrial oceans may be composed of water or other elements and compounds, the only confirmed large stable bodies of extraterrestrial surface liquids are the lakes of Titan, although there is evidence for the existence of oceans elsewhere in the Solar System. Early in their histories, Mars and Venus are theorized to have had large water oceans. The Mars ocean hypothesis suggests that nearly a third of the surface of Mars was once covered by water, compounds such as salts and ammonia dissolved in water lower its freezing point so that water might exist in large quantities in extraterrestrial environments as brine or convecting ice. Unconfirmed oceans are speculated beneath the surface of many planets and natural satellites, notably. The Solar Systems giant planets are thought to have liquid atmospheric layers of yet to be confirmed compositions. Oceans may also exist on exoplanets and exomoons, including surface oceans of water within a circumstellar habitable zone. Ocean planets are a type of planet with a surface completely covered with liquid. The concept of Ōkeanós has an Indo-European connection, Greek Ōkeanós has been compared to the Vedic epithet ā-śáyāna-, predicated of the dragon Vṛtra-, who captured the cows/rivers. Related to this notion, the Okeanos is represented with a dragon-tail on some early Greek vases, though generally described as several separate oceans, these waters comprise one global, interconnected body of salt water sometimes referred to as the World Ocean or global ocean. This concept of a body of water with relatively free interchange among its parts is of fundamental importance to oceanography. The major oceanic divisions – listed below in descending order of area and volume – are defined in part by the continents, various archipelagos, Oceans are fringed by smaller, adjoining bodies of water such as seas, gulfs, bays, bights, and straits. The Mid-Oceanic Ridge of the World are connected and form the Ocean Ridge, the continuous mountain range is 65,000 km long, and the total length of the oceanic ridge system is 80,000 km long
Ocean
–
Surface of the
Atlantic Ocean meeting
Earth 's
planetary boundary layer and
troposphere.
Ocean
–
Artist's conception of subsurface ocean of Enceladus confirmed April 3, 2014.
Ocean
–
Two models for the composition of Europa predict a large subsurface ocean of liquid water. Similar models have been proposed for other celestial bodies in the Solar System
Ocean
–
Diagram showing a possible internal structure of
Ceres
21.
Lake
–
A lake is an area of variable size filled with water, localized in a basin, that is surrounded by land, apart from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, and therefore are distinct from lagoons, Lakes can be contrasted with rivers or streams, which are usually flowing. Most lakes are fed and drained by rivers and streams, natural lakes are generally found in mountainous areas, rift zones, and areas with ongoing glaciation. Other lakes are found in endorheic basins or along the courses of mature rivers, in some parts of the world there are many lakes because of chaotic drainage patterns left over from the last Ice Age. All lakes are temporary over geologic time scales, as they will fill in with sediments or spill out of the basin containing them. The word lake comes from Middle English lake, from Old English lacu, from Proto-Germanic *lakō, cognates include Dutch laak, Middle Low German lāke as in, de, Moorlake, de, Wolfslake, de, Butterlake, German Lache, and Icelandic lækur. Also related are the English words leak and leach, none of these definitions completely excludes ponds and all are difficult to measure. For this reason, simple size-based definitions are used to separate ponds. One definition of lake is a body of water of 2 hectares or more in area, however, others have defined lakes as waterbodies of 5 hectares and above, or 8 hectares and above. Charles Elton, one of the founders of ecology, regarded lakes as waterbodies of 40 hectares or more. The term lake is used to describe a feature such as Lake Eyre. In common usage, many bear names ending with the word pond. One textbook illustrates this point with the following, In Newfoundland, for example, almost every lake is called a pond, whereas in Wisconsin, the majority of lakes on Earth are fresh water, and most lie in the Northern Hemisphere at higher latitudes. Canada, with a drainage system has an estimated 31,752 lakes larger than 3 square kilometres and an unknown total number of lakes. Finland has 187,888 lakes 500 square metres or larger, most lakes have at least one natural outflow in the form of a river or stream, which maintain a lakes average level by allowing the drainage of excess water. Some lakes do not have an outflow and lose water solely by evaporation or underground seepage or both. Many lakes are artificial and are constructed for power generation, aesthetic purposes, recreational purposes, industrial use. Globally, lakes are greatly outnumbered by ponds, of an estimated 304 million standing water bodies worldwide, 91% are 1 hectare or less in area
Lake
–
Oeschinen Lake in the
Swiss Alps
Lake
–
Lake Tahoe on the border of
California and
Nevada
Lake
–
The
Caspian Sea is either the world's largest lake or a full-fledged sea.
Lake
–
The
Seven Rila Lakes are a group of glacial lakes in the
Bulgarian Rila mountains.
22.
Carbon compounds
–
Compounds of carbon are defined as chemical substances containing carbon. More compounds of carbon exist than any chemical element except for hydrogen. Organic carbon compounds are far more numerous than inorganic carbon compounds, in general bonds of carbon with other elements are covalent bonds. Carbon is tetravalent but carbon free radicals and carbenes occur as short-lived intermediates, ions of carbon are carbocations and carbanions are also short-lived. An important carbon property is catenation as the ability to form long carbon chains, the known inorganic chemistry of the allotropes of carbon blossomed with the discovery of buckminsterfullerene in 1985, as additional fullerenes and their various derivatives were discovered. One such class of derivatives is inclusion compounds, in which an ion is enclosed by the shell of the fullerene. This inclusion is denoted by the @ symbol in endohedral fullerenes, for example, an ion consisting of a lithium ion trapped within buckminsterfullerene would be denoted Li+@C60. As with any other compound, this complex ion could in principle pair with a counterion to form a salt. Other elements are incorporated in so-called graphite intercalation compounds. Carbides are binary compounds of carbon with an element that is less electronegative than it, the most important are Al4C3, B4C, CaC2, Fe3C, HfC, SiC, TaC, TiC, and WC. It was once thought that organic compounds could only be created by living organisms, over time, however, scientists learned how to synthesize organic compounds in the lab. The number of compounds is immense and the known number of defined compounds is close to 10 million. However, a large number of such compounds are theoretically possible. By definition, a compound must contain at least one atom of carbon. With carbon bonded to metals the field of organic chemistry crosses over into organometallic chemistry, there is a rich variety of carbon chemistry that does not fall within the realm of organic chemistry and is thus called inorganic carbon chemistry. There are many oxides of carbon, of which the most common are carbon dioxide, other less known oxides include carbon suboxide and mellitic anhydride. There are also numerous unstable or elusive oxides, such as dicarbon monoxide, oxalic anhydride, there are several oxocarbon anions, negative ions that consist solely of oxygen and carbon. The most common are the carbonate and oxalate, the corresponding acids are the highly unstable carbonic acid and the quite stable oxalic acid, respectively
Carbon compounds
–
carbon monosulfide
23.
Freshwater
–
Fresh water is generally characterized by having low concentrations of dissolved salts and other total dissolved solids. The term specifically excludes seawater and brackish water although it does include mineral-rich waters such as chalybeate springs, the term sweet water has been used to describe fresh water in contrast to salt water. The term fresh water does not have the meaning as potable water. Much of the fresh water and ground water is unsuitable for drinking without some form of purification because of the presence of chemical or biological contaminants. It may also be in contact with the underlying underground water. The majority of water on Earth is in ice caps. The source of almost all water is precipitation from the atmosphere, in the form of mist, rain. Fresh water falling as mist, rain or snow contains materials dissolved from the atmosphere and material from the sea, in some cases this acid rain results in pollution of lakes and rivers. In coastal areas fresh water may contain significant concentrations of salts derived from the sea if windy conditions have lifted drops of seawater into the rain-bearing clouds. This can give rise to elevated concentrations of sodium, chloride, magnesium, significant quantities of iron may be transported in this way including the well-documented transfer of iron-rich rainfall falling in Brazil derived from sand-storms in the Sahara in north Africa. Water is an issue for the survival of all living organisms. Some can use water but many organisms including the great majority of higher plants. Out of all the water on Earth, saline water in oceans, seas and saline groundwater make up about 97% of it. Freshwater lakes contain about 87% of this surface water, including 29% in the African Great Lakes, 20% in Lake Baikal in Russia, 21% in the North American Great Lakes. Swamps have most of the balance only a small amount in rivers. In areas with no water on the ground surface, fresh water derived from precipitation may, because of its lower density. Most of the fresh water is frozen in ice sheets. Many areas suffer from lack of distribution of water, such as deserts
Freshwater
–
Earth seen from
Apollo 17 — the
Antarctic ice sheet at the bottom of the photograph contains 61% of the fresh water, or 1.7% of the total water, on Earth.
Freshwater
–
The surface of a fresh water lake.
Freshwater
–
Water fountain found in a small
Swiss village. They are used as a drinking water source for people and cattle. Almost every Alpine village has such a water source.
Freshwater
–
Air
24.
Chemosynthesis
–
Many microorganisms in dark regions of the oceans also use chemosynthesis to produce biomass from single carbon molecules. In the rare sites at which molecules are available, the energy available from the reaction between CO2 and H2 can be large enough to drive the production of biomass. Alternatively, in most oceanic environments, energy for chemosynthesis derives from reactions in which such as hydrogen sulfide or ammonia are oxidized. This may occur with or without the presence of oxygen, many chemosynthetic microorganisms are consumed by other organisms in the ocean, and symbiotic associations between chemosynthesizers and respiring heterotrophs are quite common. Large populations of animals can be supported by chemosynthetic secondary production at hydrothermal vents, methane clathrates, cold seeps, whale falls and it has been hypothesized that chemosynthesis may support life below the surface of Mars, Jupiters moon Europa, and other planets. Giant tube worms use bacteria in their trophosome to fix carbon dioxide and produce sugars, some reactions produce sulfur, hydrogen sulfide chemosynthesis, 12H2S + 6CO2 → C6H12O6 + 6H2O + 12S instead of releasing oxygen gas as in photosynthesis, the process produces solid globules of sulfur. In bacteria capable of chemosynthesis, such as purple sulfur bacteria, yellow globules of sulfur are present, in 1890, Sergei Nikolaevich Vinogradskii proposed a novel type of life process called anorgoxydant. Later, the term would also the chemoorganoautotrophy, that is. The suggestion of Vinogradskii was confirmed nearly 90 years later, when hydrothermal ocean vents were predicted to exist in the 1970s, the hot springs and strange creatures were discovered by Alvin, the worlds first deep-sea submersible, in 1977 at the Galapagos Rift. Cavanaugh later managed to confirm that this was indeed the method by which the worms could thrive, a 2004 television series hosted by Bill Nye named chemosynthesis as one of the 100 greatest scientific discoveries of all time. The bacteria synthesize methane by combining hydrogen and carbon dioxide, primary nutritional groups Autotroph Heterotroph Photosynthesis Movile Cave Chemosynthetic Communities in the Gulf of Mexico
Chemosynthesis
–
Venenivibrio stagnispumantis gains energy by oxidizing hydrogen gas.
Chemosynthesis
–
General
Chemosynthesis
–
Population ecology
25.
Zooplankton
–
Plankton are organisms drifting in oceans, seas, and bodies of fresh water. The word zooplankton is derived from the Greek zoon, meaning animal, individual zooplankton are usually microscopic, but some are larger and visible with the naked eye. Zooplankton is a categorization spanning a range of organism sizes including small protozoans, although zooplankton are primarily transported by ambient water currents, many have locomotion, used to avoid predators or to increase prey encounter rate. Ecologically important protozoan zooplankton groups include the foraminiferans, radiolarians and dinoflagellates and this wide phylogenetic range includes a similarly wide range in feeding behavior, filter feeding, predation and symbiosis with autotrophic phytoplankton as seen in corals. Zooplankton feed on bacterioplankton, phytoplankton, other zooplankton, detritus, as a result, zooplankton are primarily found in surface waters where food resources are abundant. Just as any species can be limited within a geographical region, however, species of zooplankton are not dispersed uniformly or randomly within a region of the ocean. As with phytoplankton, ‘patches’ of zooplankton species exist throughout the ocean, zooplankton patchiness can also be influenced by biological factors, as well as other physical factors. Biological factors include breeding, predation, concentration of phytoplankton, the physical factor that influences zooplankton distribution the most is mixing of the water column that affects nutrient availability and, in turn, phytoplankton production. Since they are small, zooplankton can respond rapidly to increases in phytoplankton abundance, for instance. Zooplankton can also act as a disease reservoir, crustacean zooplankton have been found to house the bacterium Vibrio cholerae, which causes cholera, by allowing the cholera vibrios to attach to their chitinous exoskeletons. This symbiotic relationship enhances the ability to survive in an aquatic environment, as the exoskeleton provides the bacterium with carbon. A global coverage database of zooplankton biomass and abundance data
Zooplankton
–
A
copepod (
Calanoida sp.)
Zooplankton
–
A
jellyfish (
Aequorea victoria)
Zooplankton
–
Krill (
Meganyctiphanes norvegica)
Zooplankton
–
Segmented worm
26.
Food chain
–
A food chain is a linear network of links in a food web starting from producer organisms and ending at apex predator species, detritivores, or decomposer species. A food chain also shows how the organisms are related with each other by the food they eat, each level of a food chain represents a different trophic level. A food chain differs from a web, because the complex network of different animals feeding relations are aggregated. Natural interconnections between food chains make it a food web, a common metric used to quantify food web trophic structure is food chain length. Food chains are used in ecological modeling. They are simplified abstractions of real food webs, but complex in their dynamics, food chain studies have an important role in ecotoxicology studies tracing the pathways and biomagnification of environmental contaminants. Producers, such as plants, are organisms that utilize solar or chemical energy to synthesize starch, all food chains must start with a producer. In the deep sea, food chains centered on hydrothermal vents, chemosynthetic bacteria and archaea use hydrogen sulfide and methane from hydrothermal vents and cold seeps as an energy source to produce carbohydrates, they form the base of the food chain. Consumers are organisms that eat other organisms, all organisms in a food chain, except the first organism, are consumers. Autotroph Heterotroph Lithotroph Trophic pyramid Predator-prey interaction
Food chain
–
Food chain in a Swedish lake.
Osprey feed on
northern pike, which in turn feed on
perch which eat
bleak that feed on freshwater
shrimp.
Food chain
–
This
food web of waterbirds from
Chesapeake Bay is a network of food chains
Food chain
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General
Food chain
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Population ecology
27.
Krill
–
Krill are small crustaceans of the order Euphausiacea, and are found in all the worlds oceans. The name krill comes from the Norwegian word krill, meaning small fry of fish, which is also often attributed to species of fish. In the Southern Ocean, one species, the Antarctic krill, Euphausia superba, makes up an estimated biomass of around 379,000,000 tonnes, making it among the species with the largest total biomass. Of this, over half is eaten by whales, seals, penguins, squid and fish each year, most krill species display large daily vertical migrations, thus providing food for predators near the surface at night and in deeper waters during the day. Krill are fished commercially in the Southern Ocean and in the waters around Japan, the total global harvest amounts to 150, 000–200,000 tonnes annually, most of this from the Scotia Sea. Most of the catch is used for aquaculture and aquarium feeds, as bait in sport fishing. In Japan, Philippines and Russia, krill are used for human consumption and are known as okiami in Japan. They are eaten as camarones in Spain, in the Philippines, it is known as alamang and it is used to make a salty paste called bagoong. Krill are also the prey of baleen whales, including the blue whale. Krill belong to the arthropod subphylum, the Crustacea. The most familiar and largest group of crustaceans, the class Malacostraca, the order Euphausiacea comprises two families. The more abundant Euphausiidae contains ten different genera with a total of 85 species, of these, the genus Euphausia is the largest, with 31 species. The lesser known family, the Bentheuphausiidae, has one species, Bentheuphausia amblyops. It is considered the most primitive extant krill species, well-known species of the Euphausiidae of commercial krill fisheries include Antarctic krill, Pacific krill and Northern krill. There have been many theories of the location of the order Euphausiacea, later, William Thomas Calman ranked the Mysidacea in the superorder Peracarida and euphausiids in the superorder Eucarida, although even up to the 1930s the order Schizopoda was advocated. It was later proposed that order Euphausiacea should be grouped with the Penaeidae in the Decapoda based on developmental similarities, as noted by Robert Gurney. The reason for debate is that krill share some morphological features of decapods. Molecular studies have not unambiguously grouped them, possibly due to the paucity of key rare species such as Bentheuphausia amblyops in krill, one study supports the monophyly of Eucarida, another groups Euphausiacea with Mysida, while yet another groups Euphausiacea with Hoplocarida
Krill
–
Euphausiacea
Krill
–
A krill swarm
Krill
–
Krill anatomy explained, using
Euphausia superba as a model
Krill
–
The
gills of krill are externally visible.
28.
Crustacean
–
Crustaceans form a large, diverse arthropod taxon which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill, woodlice and barnacles. In other words, some crustaceans are more related to insects. The 67,000 described species range in size from Stygotantulus stocki at 0.1 mm, to the Japanese spider crab with a leg span of up to 3.8 m, like other arthropods, crustaceans have an exoskeleton, which they moult to grow. Most crustaceans are free-living aquatic animals, but some are terrestrial, some are parasitic, the group has an extensive fossil record, reaching back to the Cambrian, and includes living fossils such as Triops cancriformis, which has existed apparently unchanged since the Triassic period. More than 10 million tons of crustaceans are produced by fishery or farming for human consumption, krill and copepods are not as widely fished, but may be the animals with the greatest biomass on the planet, and form a vital part of the food chain. The scientific study of crustaceans is known as carcinology, and a scientist who works in carcinology is a carcinologist, the body of a crustacean is composed of segments, which are grouped into three regions, the cephalon or head, the thorax, and the pleon or abdomen. The head and thorax may be fused together to form a cephalothorax, the crustacean body is protected by the hard exoskeleton, which must be moulted for the animal to grow. The shell around each somite can be divided into a dorsal tergum, ventral sternum, various parts of the exoskeleton may be fused together. The abdomen bears pleopods, and ends in a telson, which bears the anus, the number and variety of appendages in different crustaceans may be partly responsible for the groups success. It is unclear whether the condition is a derived state which evolved in crustaceans. Trilobites, for instance, also possessed biramous appendages, the main body cavity is an open circulatory system, where blood is pumped into the haemocoel by a heart located near the dorsum. Malacostraca have haemocyanin as the pigment, while copepods, ostracods, barnacles. The alimentary canal consists of a tube that often has a gizzard-like gastric mill for grinding food and a pair of digestive glands that absorb food. Structures that function as kidneys are located near the antennae, a brain exists in the form of ganglia close to the antennae, and a collection of major ganglia is found below the gut. In many decapods, the first pair of pleopods are specialised in the male for sperm transfer, many terrestrial crustaceans mate seasonally and return to the sea to release the eggs. Others, such as woodlice, lay their eggs on land, in most decapods, the females retain the eggs until they hatch into free-swimming larvae. Marine crustaceans are as ubiquitous in the oceans as insects are on land, some branchiurans are able to withstand rapid changes of salinity and will also switch hosts from marine to non-marine species. Krill are the layer and the most important part of the food chain in Antarctic animal communities
Crustacean
Crustacean
–
A shed
carapace of a
lady crab, part of the hard
exoskeleton
Crustacean
–
Body structure of a typical crustacean – krill
Crustacean
–
Eggs of
Potamon fluviatile, a freshwater crab
29.
Baleen whale
–
Baleen whales, known earlier as whalebone whales, form a parvorder of the infraorder Cetacea. They are a widely distributed and diverse parvorder of carnivorous marine mammals, Mysticeti comprise the families Balaenidae, Balaenopteridae, Cetotheriidae, and Eschrichtiidae. There are currently 15 species of baleen whale, while cetaceans were historically thought to have descended from mesonychids, molecular evidence supports them as relatives of even-toed ungulates. Baleen whales split from toothed whales around 34 million years ago, baleen whales range in size from the 20 ft and 6,600 lb pygmy right whale to the 112 ft and 190 t blue whale, which is also the largest creature on earth. Baleen whales can have streamlined or large bodies, depending on the feeding behavior, though not as flexible and agile as seals, baleen whales can swim very fast, with the fastest able to travel at 23 miles per hour. Baleen whales use their baleen plates to filter out food from the water by either lunge-feeding or skim-feeding, baleen whales have fused neck vertebrae, and are unable to turn their head at all. Some species are adapted for diving to great depths. They have a layer of fat, or blubber, under the skin to keep warm in the cold water, although baleen whales are widespread, most species prefer the colder waters around the Northern and Southern poles. Gray whales are specialized for feeding on bottom-dwelling crustaceans, rorquals are specialized at lunge-feeding, and have a streamlined body to reduce drag while accelerating. Right whales skim-feed, meaning they use their head to effectively take in a large amount of water. Males typically mate more than one female, although the degree of polygyny varies with the species. Male strategies for reproductive success vary between performing ritual displays or lek mating, calves are typically born in the winter and spring months and females bear all the responsibility for raising them. Mothers fast for a long period of time over the period of migration. Baleen whales produce a number of vocalizations, notably the songs of the humpback whale, the meat, blubber, baleen, and oil of baleen whales have traditionally been used by the indigenous peoples of the Arctic. Once relentlessly hunted by commercial industries for these products, cetaceans are now protected by international law, however, the North Atlantic right whale is ranked critically endangered by the International Union for Conservation of Nature. Besides hunting, baleen whales also face threats from marine pollution and it has been speculated that man-made sonar results in strandings. They have rarely been kept in captivity, and this has only attempted with juveniles or members of one of the smallest species. Baleen whales are classified under the parvorder Mysticeti, and consist of four extant families, Balaenidae, Balaenopteridae, Cetotheriidae
Baleen whale
Baleen whale
–
Baleen whales vary considerably in size
Baleen whale
–
Paired blowholes of a humpback and the V-shaped blow of a right whale
Baleen whale
30.
Species
–
In biology, a species is the basic unit of biological classification and a taxonomic rank. A species is defined as the largest group of organisms in which two individuals can produce fertile offspring, typically by sexual reproduction. While this definition is often adequate, looked at more closely it is problematic, for example, with hybridisation, in a species complex of hundreds of similar microspecies, or in a ring species, the boundaries between closely related species become unclear. Other ways of defining species include similarity of DNA, morphology, all species are given a two-part name, a binomial. The first part of a binomial is the genus to which the species belongs, the second part is called the specific name or the specific epithet. For example, Boa constrictor is one of four species of the Boa genus, Species were seen from the time of Aristotle until the 18th century as fixed kinds that could be arranged in a hierarchy, the great chain of being. In the 19th century, biologists grasped that species could evolve given sufficient time, Charles Darwins 1859 book The Origin of Species explained how species could arise by natural selection. Genes can sometimes be exchanged between species by horizontal transfer, and species may become extinct for a variety of reasons. In his biology, Aristotle used the term γένος to mean a kind, such as a bird or fish, a kind was distinguished by its attributes, for instance, a bird has feathers, a beak, wings, a hard-shelled egg, and warm blood. A form was distinguished by being shared by all its members, Aristotle believed all kinds and forms to be distinct and unchanging. His approach remained influential until the Renaissance, when observers in the Early Modern period began to develop systems of organization for living things, they placed each kind of animal or plant into a context. Many of these early delineation schemes would now be considered whimsical, animals likewise that differ specifically preserve their distinct species permanently, one species never springs from the seed of another nor vice versa. In the 18th century, the Swedish scientist Carl Linnaeus classified organisms according to shared physical characteristics and he established the idea of a taxonomic hierarchy of classification based upon observable characteristics and intended to reflect natural relationships. At the time, however, it was widely believed that there was no organic connection between species, no matter how similar they appeared. However, whether or not it was supposed to be fixed, by the 19th century, naturalists understood that species could change form over time, and that the history of the planet provided enough time for major changes. Jean-Baptiste Lamarck, in his 1809 Zoological Philosophy, described the transmutation of species, proposing that a species could change over time, in 1859, Charles Darwin and Alfred Russel Wallace provided a compelling account of evolution and the formation of new species. Darwin argued that it was populations that evolved, not individuals and this required a new definition of species. Darwin concluded that species are what appear to be, ideas
Species
–
John Ray
Species
–
Carl Linnaeus believed in the fixity of species.
. Science. 291 (5513): 2594. Retrieved 2017-08-03.
. PMID 24143135. doi:10.1371/journal.pbio.1001682.
