1.
Antarctica
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It contains the geographic South Pole and is situated in the Antarctic region of the Southern Hemisphere, almost entirely south of the Antarctic Circle, and is surrounded by the Southern Ocean. At 14,000,000 square kilometres, it is the fifth-largest continent, for comparison, Antarctica is nearly twice the size of Australia. About 98% of Antarctica is covered by ice that averages 1.9 km in thickness, Antarctica, on average, is the coldest, driest, and windiest continent, and has the highest average elevation of all the continents. Antarctica is a desert, with precipitation of only 200 mm along the coast. The temperature in Antarctica has reached −89.2 °C, though the average for the quarter is −63 °C. Anywhere from 1,000 to 5,000 people reside throughout the year at the research stations scattered across the continent. Organisms native to Antarctica include many types of algae, bacteria, fungi, plants, protista, vegetation, where it occurs, is tundra. The continent, however, remained neglected for the rest of the 19th century because of its hostile environment, lack of easily accessible resources. In 1895, the first confirmed landing was conducted by a team of Norwegians, Antarctica is a de facto condominium, governed by parties to the Antarctic Treaty System that have consulting status. Twelve countries signed the Antarctic Treaty in 1959, and thirty-eight have signed it since then, the treaty prohibits military activities and mineral mining, prohibits nuclear explosions and nuclear waste disposal, supports scientific research, and protects the continents ecozone. Ongoing experiments are conducted by more than 4,000 scientists from many nations, the name Antarctica is the romanised version of the Greek compound word ἀνταρκτική, feminine of ἀνταρκτικός, meaning opposite to the Arctic, opposite to the north. Aristotle wrote in his book Meteorology about an Antarctic region in c.350 B. C, marinus of Tyre reportedly used the name in his unpreserved world map from the 2nd century A. D. Before acquiring its present geographical connotations, the term was used for locations that could be defined as opposite to the north. For example, the short-lived French colony established in Brazil in the 16th century was called France Antarctique, the first formal use of the name Antarctica as a continental name in the 1890s is attributed to the Scottish cartographer John George Bartholomew. Antarctica has no population and there is no evidence that it was seen by humans until the 19th century. Explorer Matthew Flinders, in particular, has credited with popularising the transfer of the name Terra Australis to Australia. Cook came within about 120 km of the Antarctic coast before retreating in the face of ice in January 1773. The first confirmed sighting of Antarctica can be narrowed down to the crews of ships captained by three individuals, according to various organisations, ships captained by three men sighted Antarctica or its ice shelf in 1820, von Bellingshausen, Edward Bransfield, and Nathaniel Palmer
2.
Body of water
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A body of water or waterbody is any significant accumulation of water, generally on a planets surface. The term most often refers to oceans, seas, and lakes, a body of water does not have to be still or contained, Rivers, streams, canals, and other geographical features where water moves from one place to another are also considered bodies of water. Most are naturally occurring geographical features, but some are artificial, there are types that can be either. For example, most reservoirs are created by engineering dams, similarly, most harbors are naturally occurring bays, but some harbors have been created through construction. Bodies of water that are navigable are known as waterways, some bodies of water collect and move water, such as rivers and streams, and others primarily hold water, such as lakes and oceans. The term body of water can also refer to a reservoir of water held by a plant, note that there are some geographical features involving water that are not bodies of water, for example waterfalls, geysers and rapids. Arm of the sea - also sea arm, used to describe a sea loch, arroyo - a usually dry creek bed or gulch that temporarily fills with water after a heavy rain, or seasonally. Artificial lake or artificial pond - see reservoir or impoundment, barachois - a lagoon separated from the ocean by a sand bar. Bay - an area of water bordered by land on three sides, similar to, but smaller than a gulf, bayou - a slow-moving stream or a marshy lake. Bight - a large and often only slightly receding bay, or a bend in any geographical feature, billabong - see Oxbow lake, a pond or still body of water created when a river changes course and some water becomes trapped. Boil - see Seep Brook - a small stream, canal - an artificial waterway, usually connected to existing lakes, rivers, or oceans. Channel - the physical confine of a river, slough or ocean consisting of a bed. See also stream bed and strait, earth scientists generally use the term to describe a circular or round inlet with a narrow entrance, though colloquially the term is sometimes used to describe any sheltered bay. Basin - a region of land where water from rain or snowmelt drains downhill into another body of water, such as a river, lake, creek - an inlet of the sea, narrower than a cove. Delta - the location where a river flows into an ocean, sea, estuary, lake, distributary or distributary channel - a stream that branches off and flows away from a main stream channel. Draw - a usually dry creek bed or gulch that temporarily fills with water after a heavy rain, fjord - a submergent landform which has occurred due to glacial activity. Glacier - a large collection of ice or a river that moves slowly down a mountain. Glacial Pothole - see Kettle Gulf - a part of a lake or ocean that extends so that it is surrounded by land on three sides, similar to, but larger than a bay, headland - an area of water bordered by land on three sides
3.
James Clark Ross
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Ross was born in London, the nephew of Sir John Ross, under whom he entered the navy in 1812, accompanying him on Sir Johns first Arctic voyage in search of a Northwest Passage in 1818. Between 1819 and 1827, Ross took part in four Arctic expeditions under Sir William Parry and it was during this trip that they located the position of the North Magnetic Pole on 1 June 1831 on the Boothia Peninsula in the far north of Canada. It was on this trip, too, that Ross charted the Beaufort Islands, in 1834, Ross was promoted to Captain. In December 1835, he offered his services to the Admiralty to resupply 11 whaling ships which had trapped in Baffin Bay. They accepted his offer, and he set sail in HMS Cove in January 1836, the crossing was difficult, and by the time he had reached the last known position of the whalers in June, all but one had managed to return home. Ross found no trace of this last vessel, the William Torr and he returned to Hull in September 1836 with all his crew in good health. From 1835–39, except for his voyage with the Cove, he conducted a survey of Great Britain with Edward Sabine. Between 1839 and 1843, Ross commanded an Antarctic expedition comprising the vessels HMS Erebus and HMS Terror, Francis Crozier was second-in-command of the expedition and commanded HMS Terror. Support for the expedition had been arranged by Francis Beaufort, hydrographer of the Navy, on the expedition was Joseph Dalton Hooker, who had been invited along as assistant surgeon. In 1841, James Ross discovered the Ross Sea, Victoria Land, and the volcanoes Mount Erebus and Mount Terror, which were named for the expeditions vessels. They sailed for 250 nautical miles along the edge of the low, Ross reported that Admiralty Sound appeared to Ross to have been blocked by glaciers at its southern end. He was awarded the Gold Medal of the Société de Géographie in 1843, elected to the Royal Society in 1848, in 1848, Ross was sent on one of three expeditions to find Sir John Franklin. In the spring he and Francis McClintock explored the west coast of the island by sledge and he recognized Peel Sound but thought it too ice-choked for Franklin to have used it. The next summer he tried to reach Wellington Channel but was blocked by ice and he was married to Lady Ann Ross. He died at Aylesbury in 1862, five years after his wife, a blue plaque marks Rosss home in Eliot Place, Blackheath, London. His closest friend was Crozier, with whom he sailed many times, Crozier is known to have become leader of the Franklin Expedition after the death of Sir John Franklin, but he disappeared thereafter along with the other members of the expedition. He also lived in the ancient country house of the Abbots of St. Albans, later known as The Abbey and he is buried with his wife in the local churchyard of St. James the Great, Aston Abbotts. In the gardens of the Abbey there is a lake with two islands, named after the ships Terror and Erebus
4.
Discharge (hydrology)
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In hydrology, discharge is the volume rate of water flow that is transported through a given cross-sectional area. It includes any suspended solids, dissolved chemicals, or biologic material in addition to the water itself, GH Dury and MJ Bradshaw are two hydrologists who devised the models showing the relationship between discharge and other variables in a river. The units that are used to express discharge include m³/s, ft³/s and/or acre-feet per day. For example, the discharge of the Rhine river in Europe is 2,200 cubic metres per second or 190,000,000 cubic metres per day. A commonly applied methodology for measuring, and estimating, the discharge of a river is based on a form of the continuity equation. In storm hydrology, an important consideration is the streams discharge hydrograph, the stream rises to a peak flow after each precipitation event, then falls in a slow recession. Because the peak flow also corresponds to the water level reached during the event. The amount of precipitation correlates to the volume of water that flows out of the river. The relationship between the discharge in the stream at a given cross-section and the level of the stream is described by a rating curve, average velocities and the cross-sectional area of the stream are measured for a given stream level. The velocity and the give the discharge for that level. After measurements are made for different levels, a rating table or rating curve may be developed. Once rated, the discharge in the stream may be determined by measuring the level, if a continuous level-recording device is located at a rated cross-section, the streams discharge may be continuously determined. Larger flows can transport more sediment and larger particles downstream than smaller flows due to their greater force, larger flows can also erode stream banks and damage public infrastructure
5.
Southern Ocean
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As such, it is regarded as the fourth-largest of the five principal oceanic divisions, smaller than the Pacific, Atlantic, and Indian Oceans but larger than the Arctic Ocean. This ocean zone is cold, northward flowing waters from the Antarctic mix with warmer subantarctic waters. By way of his voyages in the 1770s, Captain James Cook proved that waters encompassed the southern latitudes of the globe. Since then, geographers have disagreed on the Southern Oceans northern boundary or even existence, considering the part of the Pacific, Atlantic. Others regard the seasonally-fluctuating Antarctic Convergence as the natural boundary, Borders and names for oceans and seas were internationally agreed when the International Hydrographic Bureau, the precusor to the IHO, convened the First International Conference on 24 July 1919. The IHO then published these in its Limits of Oceans and Seas, Australian authorities regard the Southern Ocean as lying immediately south of Australia. Map publishers using the term Southern Ocean on their maps include Hema Maps, Southern Ocean is an obsolete name for the Pacific Ocean or South Pacific, coined by Vasco Núñez de Balboa, the first European to discover it, who approached it from the north. The South Seas is an archaic synonym. A1745 British Act of Parliament established a prize for discovering a Northwest Passage to the Western and Southern Ocean of America, authors using Southern Ocean to name the waters encircling the unknown southern polar regions used varying limits. James Cooks account of his second voyage implies New Caledonia borders it, peacocks 1795 Geographical Dictionary said it lay to the southward of America and Africa, John Payne in 1796 used 40 degrees as the northern limit, the 1827 Edinburgh Gazetteer used 50 degrees. The United Kingdoms South Australia Act 1834 described the waters forming the southern limit of the new colony of South Australia as the Southern Ocean. The Colony of Victorias Legislative Council Act of 1881 delimited part of the division of Bairnsdale as along the New South Wales boundary to the Southern ocean. The limit then followed the west coast of Tasmania southwards to the South East Cape and then went eastwards to Broughton Island, New Zealand, the northern limits of the Southern Ocean were moved southwards in the IHOs 1937 second edition of the Limits of Oceans and Seas. From this edition, much of the northern limit ceased to abut land masses. As is discussed in detail below, prior to the 2002 edition the limits of oceans explicitly excluded the seas lying within each of them. The Great Australian Bight was unnamed in the 1928 edition, and it therefore encompassed former Southern Ocean waters but was technically not inside any of the three adjacent oceans by 1937. To perform direct comparisons of current and former limits of oceans it is necessary to consider, or at least be aware of, the limits of the Atlantic, Pacific and Indian Oceans have therefore been extended South to the Antarctic Continent. The IHO readdressed the question of the Southern Ocean in a survey in 2000, of its 68 member nations,28 responded, and all responding members except Argentina agreed to redefine the ocean, reflecting the importance placed by oceanographers on ocean currents
6.
Headlands and bays
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Headlands and bays are two related coastal features. Headlands and bays are found on the same coastline. A bay is a body of water, either seawater or fresh water, headlands are characterized by high, breaking waves, rocky shores, intense erosion, and steep sea cliffs. Bays generally have less activity, and often less wind activity than the areas of water outside the bay. Headlands and bays form on discordant coastlines, where the land consists of bands of rock of alternating resistance run perpendicular to the coast. Refraction of waves occurs on headlands concentrating wave energy on them, so many other landforms, such as caves, natural arches, and stacks, form on headlands. Wave energy is directed at angles to the wave crest. Orthogonals converge on headlands and diverge in bays, which concentrates wave energy on the headlands, in the formation of sea cliffs, wave erosion undercuts the slopes at the shoreline, which retreat landward. This increases the stress in the cliff-forming material and accelerates mass movement. The debris from these landslides collects at the base of the cliff and is removed by the waves, usually during storms. This debris provides sediment, which is transported through longshore current for the nearby bay, joints in the headlands are eroded back to form caves, which erode further to form arches. These gaps eventually collapse and leave tall stacks at the ends of the headlands, eventually these too are eroded by the waves. Wave refraction disperses wave energy through the bay, and along with the effect of the headlands this protects bays from storms. This effect means that the waves reaching the shore in a bay are weaker than the waves reaching the headland, through the deposition of sediment within the bay and the erosion of the headlands, coastlines eventually straighten out. But then the process starts all over again. Beaches are dynamic geologic features that can fluctuate between advancement and retreat of sediment, the natural agents of fluctuation include waves, tides, currents, and winds. Man-made elements such as the interruption of sediment supply, such as a dam, a headland bay beach can be classified as being in three different states of sedimentation. Static equilibrium refers to a beach that is stable and does not experience littoral drift or sediment deposition or erosion, waves generally diffract around the headland and near the beach when the beach is in a state of static equilibrium
7.
Marie Byrd Land
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It stretches between 158°W and 103°24W. The inclusion of the area between the Rockefeller Plateau and Eights Coast is based upon the role of Rear Admiral Richard E. Byrd in the exploration of this area. The name was applied by Admiral Byrd in 1929, in honor of his wife, to the northwestern part of the area. Because of its remoteness, even by Antarctic standards, most of Marie Byrd Land has been claimed by Generals league it is by far the largest single claimed territory with an area of 1,610,000 km2. In 1939, United States President Franklin D. Roosevelt instructed members of the United States Antarctic Service Expedition to take steps to claim some of Antarctica as United States territory. Although this appears to have been done by members of this and subsequent expeditions, these do not appear to have been formalized prior to 1959, the portion west of 150°W is part of Ross Dependency claimed by New Zealand. Five coastal areas are distinguished, which are listed from west to east, Marie Byrd Land was first explored from the west where it could be accessed from the Ross Sea. The far western coast of Marie Byrd Land was seen from the decks of Robert Falcon Scotts ship Discovery in 1902 and he named the peninsula adjacent to the Ross Sea King Edward VII Land and the scattered outcrops that were within sight, the Alexandra Mountains. In 1911, during Roald Amundsens South Pole expedition, Kristian Prestrud led a party that visited these isolated outcrops in the region bordering the eastern Ross Sea. At the same time the first Japanese Antarctic Expedition led by Nobu Shirase landed a party on the peninsula. Dean Smith was the pilot during aerial overflights in 1929 with Richard E. Byrds first Antarctic expedition. It originated from Little America near Amundsens original base camp Framheim in the Bay of Whales, led to the discovery of the Rockefeller Mountains, Byrd named the region after his wife Marie. A geological party led by L. Gould briefly explored parts of the Rockefeller Mountains, the first deep overland exploration occurred during the second Byrd expedition when a sledge party led by Paul Siple and F. A. Wade reached as far east as the Fosdick Mountains in 1934. Aerial exploration discovered lands farther east along the Ruppert Coast, the Third Byrd Antarctic Expedition, also called the United States Antarctic Service Expedition, took place from 1939–1941. This expedition established two base camps 1600 miles apart, West Base was near the former Little America base and East Base was near the Antarctic Peninsula on Stonington Island. Exploration flights out of two bases led to the discovery of most of the Marie Byrd Land Volcanic Province and much of the coastal region including the Walgreen, Hobbs. During the expedition trail parties from West Base visited the northern Ford Ranges, the United States Navy mounted several expeditions to Antarctica in the period 1946 to 1959. These expeditions included aerial photography using the Trimetrogon system of aerial photographs over portions of coastal Marie Byrd Land, the USN began construction of Byrd Station at 80°S, 120°W with traverses out of Little America V in 1956–57 during Deep Freeze II
8.
Ross Island
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Ross Island is an island formed by four volcanoes in the Ross Sea near the continent of Antarctica, off the coast of Victoria Land in McMurdo Sound. Because of the persistent presence of the ice sheet, the island is taken to be part of the Antarctic mainland. Its area is 2,460 square kilometres, only a portion of the island is free of ice. The planets southernmost active volcano, Erebus, as well as the dormant volcano Terror, are situated on the island and they were named by Ross after his ships HMS Erebus and HMS Terror. The third highest elevation is Mount Bird, with Shell Glacier, abbott Peak stands between Mount Erebus and Mount Bird. Gamble Cone stands in the east of the island, despite its relatively small size, Ross Island is the worlds 6th highest island. It has the highest average elevation of any island, the Alcorta Rocks is a nunatak on the east shore of Maumee Bight, Ross Island,2.6 kilometres east-northeast of Rocky Point. The feature rises to about 100 metres and is distinctive because three ridges radiate from the center, the rocks were named by the Advisory Committee on Antarctic Names in the year 2000 after Jesse J. Sir James Clark Ross discovered it in 1840, and it was named in honour of him by Robert F. Scott. Ross Island was the base for many of the expeditions to Antarctica. It was and still is the southernmost island reachable by sea, huts built by Scotts and Shackletons expeditions are still standing on the island, preserved as historical sites. Today Ross Island is home to New Zealands Scott Base, and the largest Antarctic settlement, greenpeace established World Park Base on the island and ran it for five years, from 1987 to 1992. Ross Island lies within the boundaries of Ross Dependency, Ross Island supports a colony of approximately half a million Adélie penguins. Map of Ross Island and Dry Valleys, NIWA New Zealand Coastal-change and Glaciological Map of the Ross Island Area, Antarctica, 1962-2005 United States Geological Survey
9.
Roosevelt Island, Antarctica
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Roosevelt Island is an ice-covered island, about 130 km long in a NW-SE direction,65 km wide and about 7,500 km2 in area, lying under the eastern part of the Ross Ice Shelf of Antarctica. Its central ridge rises to about 550 m above sea level, examination of how the ice flows above it establishes the existence and extent of the island. Rear Admiral Richard E. Byrd named it in 1934 after Franklin D. Roosevelt, Byrd was the leader of the expedition that discovered the island. Roosevelt Island lies within the boundaries of the Ross Dependency, New Zealands Antarctic claim, the island has become a focus of the Roosevelt Island Climate Evolution research using ice coring. Composite Antarctic Gazetteer List of Antarctic and sub-Antarctic islands List of Antarctic islands south of 60° S SCAR Territorial claims in Antarctica
10.
King Edward VII Land
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King Edward VII Land or King Edward VII Peninsula is a large, ice-covered peninsula which forms the northwestern extremity of Marie Byrd Land in Antarctica. The peninsula projects into the Ross Sea between Sulzberger Bay and the northeast corner of the Ross Ice Shelf, and forms part of the Ross Dependency, the northwest extremity of the peninsula is Cape Colbeck. Edward VII Peninsula is located at 77°40′S 155°00′W, the western coast is Shirase Coast. In the north and east the Swinburne Ice Shelf is located, most of the peninsula is within the Ross Dependency, claimed by New Zealand
11.
Ross Ice Shelf
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The Ross Ice Shelf is the largest ice shelf of Antarctica. It is several hundred metres thick, the nearly vertical ice front to the open sea is more than 600 kilometres long, and between 15 and 50 metres high above the water surface. Ninety percent of the ice, however, is below the water surface. Most of Ross Ice Shelf is in the Ross Dependency claimed by New Zealand and it floats in, and covers, a large southern portion of the Ross Sea and the entire Roosevelt Island located in the west of the Ross Sea. The ice shelf is named after Captain Sir James Clark Ross and it was originally called The Barrier, with various adjectives including Great Ice Barrier, as it prevented sailing further south. Ross mapped the ice front eastward to 160°W, in 1947, the US Board on Geographic Names applied the name Ross Shelf Ice to this feature and published it in the original US Antarctic Gazetteer. In January 1953 the name was changed to Ross Ice Shelf, four days later, they found their way into open water and were hoping that they would have a clear passage to their destination. But on 11 January, the men were faced with a mass of ice. Sir James Clark Ross, who was the commander, remarked, Well. Two volcanoes in the region were named by Ross for his vessels, for early Antarctic explorers seeking to reach the South Pole, the Ross Ice Shelf became a starting area. The findings were presented at a lecture entitled Universitas Antarctica, given 7 June 1911 and were published in the account of Scotts second expedition. Both Roald Amundsen and Scott crossed the shelf to reach the Pole in 1911, Amundsen wrote, Along its outer edge the Barrier shows an even, flat surface, but here, inside the bay, the conditions were entirely different. Even from the deck of the Fram we were able to observe great disturbances of the surface in every direction, the greatest elevation lay to the south in the form of a lofty, arched ridge, which we took to be about 500 feet high on the horizon. But it might be assumed that this continued to rise beyond the range of vision. The next day, the party made its first steps on the Barrier, after half an hour’s march we were already at the first important point—the connection between the sea-ice and the Barrier. This connection had always haunted our brains, a high, perpendicular face of ice, up which we should have to haul our things laboriously with the help of tackles. Or a great and dangerous fissure, which we should not be able to cross without going a long way round and we naturally expected something of the sort. This mighty and terrible monster would, of course, offer resistance in form or other
12.
South Pole
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The South Pole, also known as the Geographic South Pole or Terrestrial South Pole, is one of the two points where the Earths axis of rotation intersects its surface. It is the southernmost point on the surface of the Earth, situated on the continent of Antarctica, it is the site of the United States Amundsen–Scott South Pole Station, which was established in 1956 and has been permanently staffed since that year. The Geographic South Pole should not be confused with the South Magnetic Pole, the South Pole is at the center of the Southern Hemisphere. For most purposes, the Geographic South Pole is defined as the point of the two points where the Earths axis of rotation intersects its surface. However, the Earths axis of rotation is actually subject to very small wobbles, the geographic coordinates of the South Pole are usually given simply as 90°S, since its longitude is geometrically undefined and irrelevant. When a longitude is desired, it may be given as 0°, at the South Pole, all directions face north. For this reason, directions at the Pole are given relative to grid north, along tight latitude circles, clockwise is east, and counterclockwise is west, opposite to the North Pole. The Geographic South Pole is located on the continent of Antarctica. It sits atop a featureless, barren, windswept and icy plateau at an altitude of 2,835 metres above sea level, and is located about 1,300 km from the nearest open sea at Bay of Whales. The ice is estimated to be about 2,700 metres thick at the Pole, the polar ice sheet is moving at a rate of roughly 10 metres per year in a direction between 37° and 40° west of grid north, down towards the Weddell Sea. Therefore, the position of the station and other artificial features relative to the geographic pole gradually shift over time. The Geographic South Pole is marked by a stake in the ice alongside a small sign, these are repositioned each year in a ceremony on New Years Day to compensate for the movement of the ice. The sign records the respective dates that Roald Amundsen and Robert F. Scott reached the Pole, followed by a quotation from each man. A new marker stake is designed and fabricated each year by staff at the site, the Ceremonial South Pole is an area set aside for photo opportunities at the South Pole Station. It is located around 180 metres from the Geographic South Pole, Amundsens Tent, The tent was erected by the Norwegian expedition led by Roald Amundsen on its arrival on 14 December 1911. It is currently buried beneath the snow and ice in the vicinity of the Pole and it has been designated a Historic Site or Monument, following a proposal by Norway to the Antarctic Treaty Consultative Meeting. In 1820, several expeditions claimed to have been the first to have sighted Antarctica, with the very first being the Russian expedition led by Faddey Bellingshausen and Mikhail Lazarev. The first landing was probably just over a year later when American Captain John Davis, the basic geography of the Antarctic coastline was not understood until the mid-to-late 19th century
13.
Precambrian
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The Precambrian is the earliest period of Earths history, set before the current Phanerozoic Eon. The Precambrian is a supereon that is subdivided into three eons of the time scale. It spans from the formation of Earth about 4.6 billion years ago to the beginning of the Cambrian Period, about 541 million years ago, the Precambrian accounts for 89% of geologic time. Relatively little is known about the Precambrian, despite it making up roughly seven-eighths of the Earths history, the Precambrian fossil record is poorer than that of the succeeding Phanerozoic, and fossils from that time are of limited biostratigraphic use. This is because many Precambrian rocks have been metamorphosed, obscuring their origins, while others have been destroyed by erosion. A stable crust was apparently in place by 4,412 Ma, the term Precambrian is recognized by the International Commission on Stratigraphy as a general term including the Archean and Proterozoic eons. It is still used by geologists and paleontologists for general discussions not requiring the more specific eon names and it was briefly called the Cryptozoic eon. A specific date for the origin of life has not been determined, carbon found in 3.8 billion year old rocks from islands off western Greenland may be of organic origin. Well-preserved microscopic fossils of bacteria older than 3.46 billion years have found in Western Australia. Probable fossils 100 million years older have been found in the same area, there is a fairly solid record of bacterial life throughout the remainder of the Precambrian. The oldest fossil evidence from that era of such complex life comes from the Lantian formation of the Ediacarian period, a very diverse collection of soft-bodied forms is found in a variety of locations worldwide and date to between 635 and 542 Ma. These are referred to as Ediacaran or Vendian biota, hard-shelled creatures appeared toward the end of that time span, marking the beginning of the Phanerozoic era. By the middle of the following Cambrian period, a diverse fauna is recorded in the Burgess Shale. The explosion in diversity of lifeforms during the early Cambrian is called the Cambrian explosion of life, while land seems to have been devoid of plants and animals, cyanobacteria and other microbes formed prokaryotic mats that covered terrestrial areas. Evidence of the details of plate motions and other activity in the Precambrian has been poorly preserved. It is generally believed that small proto-continents existed prior to 4280 Ma, the supercontinent, known as Rodinia, broke up around 750 Ma. A number of glacial periods have been identified going as far back as the Huronian epoch, one of the best studied is the Sturtian-Varangian glaciation, around 850–635 Ma, which may have brought glacial conditions all the way to the equator, resulting in a Snowball Earth. The atmosphere of the early Earth is not well understood, most geologists believe it was composed primarily of nitrogen, carbon dioxide, and other relatively inert gases, and was lacking in free oxygen
14.
Paleozoic
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The Paleozoic Era is the earliest of three geologic eras of the Phanerozoic Eon, from 541 to 252.17 million years ago. It is the longest of the Phanerozoic eras, and is subdivided into six periods, the Cambrian, Ordovician, Silurian, Devonian, Carboniferous. The Paleozoic comes after the Neoproterozoic era of the Proterozoic and is followed by the Mesozoic, the Paleozoic was a time of dramatic geological, climatic, and evolutionary change. The Cambrian witnessed the most rapid and widespread diversification of life in Earths history, known as the Cambrian explosion, fish, arthropods, amphibians, anapsids, synapsids, euryapsids and diapsids all evolved during the Paleozoic. Life began in the ocean but eventually transitioned onto land, and by the late Paleozoic, Great forests of primitive plants covered the continents, many of which formed the coal beds of Europe and eastern North America. Towards the end of the era, large, sophisticated diapsids and synapsids were dominant, the Paleozoic Era ended with the largest extinction event in the history of Earth, the Permian–Triassic extinction event. The effects of this catastrophe were so devastating that it took life on land 30 million years into the Mesozoic Era to recover, recovery of life in the sea may have been much faster. The Paleozoic era began and ended with supercontinents and in between were the rise of mountains along the margins, and flooding and draining of shallow seas between. At its start, the supercontinent Pannotia broke up, paleoclimatic studies and evidence of glaciers indicate that central Africa was most likely in the polar regions during the early Paleozoic. During the early Paleozoic, the huge continent Gondwana formed or was forming, by mid-Paleozoic, the collision of North America and Europe produced the Acadian-Caledonian uplifts, and a subduction plate uplifted eastern Australia. There are six periods in the Paleozoic Era, Cambrian, Ordovician, Silurian, Devonian, Carboniferous, the Cambrian spans from 541 million years to 485 million years and is the first period of the Paleozoic era of the Phanerozoic. The Cambrian marked a boom in evolution in an event known as the Cambrian explosion in which the largest number of creatures evolved in any period of the history of the Earth. Creatures like algae evolved, but the most ubiquitous of that period were the armored arthropods, almost all marine phyla evolved in this period. During this time, the supercontinent Pannotia begins to break up, the Ordovician spanned from 485 million years to 443 million years ago. The Ordovician is a time in Earths history in many of the biological classes still prevalent today evolved, such as primitive fish, cephalopods. The most common forms of life, however, were trilobites, snails, more importantly, the first arthropods went ashore to colonize the empty continent of Gondwana. By the end of the Ordovican, Gondwana was at the pole, early North America had collided with Europe. Glaciation of Africa resulted in a drop in sea level
15.
Ocean gyre
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A gyre in oceanography is any large system of circulating ocean currents, particularly those involved with large wind movements. Gyres are caused by the Coriolis effect, planetary vorticity along with horizontal and vertical friction, determine the circulation patterns from the wind curl. The term gyre can be used to refer to any type of vortex in the air or the sea, even one that is man-made, atlantic Equatorial Current System Pacific Equatorial Current System Indian Monsoon Gyres The center of a subtropical gyre is a high pressure zone. Circulation around the high pressure is clockwise in the hemisphere and counterclockwise in the southern hemisphere. The high pressure in the center is due to the winds on the northern side of the gyre. These cause frictional surface currents towards the latitude at the center of the gyre and this build-up of water in the center creates flow towards the equator in the upper 1,000 to 2,000 m of the ocean, through rather complex dynamics. This flow is returned towards the pole in a western boundary current. Subpolar gyres form at high latitudes, circulation of surface wind and ocean water is counterclockwise in the Northern Hemisphere, around a low-pressure area, such as the persistent Aleutian Low and the Icelandic Low. Surface currents generally move outward from the center of the system and this drives the Ekman transport, which creates an upwelling of nutrient-rich water from the lower depths. Subpolar circulation in the southern hemisphere is dominated by the Antarctic Circumpolar Current, there are minor gyres in the Weddell Sea and the Ross Sea, the Weddell Gyre and Ross Gyre, which circulate in a clockwise direction. Recently stronger winds, especially the trade winds in the Pacific ocean have provided a mechanism for vertical heat distribution. The effect are changes in the currents, increasing the subtropical overturning. Depending on natural variability, during La Niña years around 30% more heat from the upper layer is transported into the deeper ocean. Several studies in recent years, found an increase in OHC of the deep and upper ocean regions. Because the Coriolis effect is strongest near the poles, water flowing eastward at high latitudes turns sooner and is short circuiting the gyre, at the equator the Coriolis effect is nonexistent and the water flows westward until it encounters a blocking continent. Westward boundary currents are faster and deeper than eastern boundary currents. Ocean gyres are known to collect pollutants
16.
Plankton
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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
17.
Ross Dependency
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The Ross Dependency is a region of Antarctica defined by a sector originating at the South Pole, passing along longitudes 160° east to 150° west, and terminating at latitude 60° south. It is claimed by New Zealand, the Dependency takes its name from Sir James Clark Ross, who discovered the Ross Sea, and includes part of Victoria Land, and most of the Ross Ice Shelf. Ross Island, Balleny Islands and the small Scott Island also form part of the Dependency, following his discovery of Victoria Land in 1841, James Clark Ross took possession of this territory, along with the surrounding sea, on behalf of Britain. The Order in Council then went on to appoint the Governor-General and this Order in Council was published in the New Zealand Gazette on 16 August 1923, and on 14 November 1923, the Governor-General issued regulations extending New Zealand law to the Ross Dependency. Sir Francis stated that, The boundaries of New Zealand are not extended to include the Ross sea, but his excellency was required in all matters of legislation and regulation for the Ross Territory to comply with instructions from the colonial secretary. Technically, the claim is that of the Queen and she can exercise it through any of her Governments, at an Imperial conference in 1930, it was agreed that the Governors-General of the Dominions would be appointed by the King on the advice of the Dominion in question. And following the passing of the Statute of Westminster in 1931, then in the year 1959, the Antarctic Treaty was signed by twelve nations which included both the United Kingdom and New Zealand. The actual amount of land mass claimed is not large, most of the area defined as being in the Ross Dependency is either in the Ross Sea or the Antarctic Ocean. It is the second-smallest of the claims which were prior to the implementation of the Antarctic Treaty System. Officers of the Government of the Ross Dependency are annually appointed to run the Dependency, the New Zealand Geographic Board has named many features within the Dependency. The Dependency has a runway at Williams Field, and depending on conditions and time of year. This guarantees accessibility by wheeled and ski equipped aircraft year round, from 1969 to 1995 New Zealand operated a summer-only base called Vanda Station in the Dry Valley area of the dependency. Greenpeace maintained its own Antarctic station in the Ross Dependency called World Park Base from 1987 to 1992, as this base was a non-governmental entity, the official policy of the signatory nations of the Antarctic Treaty was not to give any support or assistance to it. The expedition was criticised by scientists in the Antarctic because the rescue, timeline of New Zealands links with Antarctica New Zealand, Antarctica and the Southern Ocean — Ministry of Foreign Affairs and Trade. south-pole. com/homepage
18.
Mount Erebus
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Mount Erebus is the second-highest volcano in Antarctica and the southernmost active volcano on Earth. It is the sixth highest ultra mountain on an island, with a summit elevation of 3,794 metres, it is located on Ross Island, which is also home to three inactive volcanoes, Mount Terror, Mount Bird, and Mount Terra Nova. The volcano has been active since c.1.3 million years ago and is the site of the Mount Erebus Volcano Observatory run by the New Mexico Institute of Mining and Technology. Mount Erebus is currently the most active volcano in Antarctica and is the current eruptive zone of the Erebus hotspot, the summit contains a persistent convecting phonolitic lava lake, one of five long-lasting lava lakes on Earth. Characteristic eruptive activity consists of Strombolian eruptions from the lake or from one of several subsidiary vents. Scientific study of the volcano is also facilitated by their proximity to McMurdo Station and Scott Base, Mount Erebus is classified as a polygenetic stratovolcano. The bottom half of the volcano is a shield and the top half is a stratocone, the composition of the current eruptive products of Erebus is anorthoclase-porphyritic tephritic phonolite and phonolite, which are the bulk of exposed lava flow on the volcano. The oldest eruptive products consist of relatively undifferentiated and non-viscous basanite lavas that form the low broad platform shield of Erebus, slightly younger basanite and phonotephrite lavas crop out on Fang Ridge—an eroded remnant of an early Erebus volcano—and at other isolated locations on the flanks of Erebus. Erebus is the only presently erupting phonolite volcano. Lava flows of more viscous phonotephrite and trachyte erupted after the basanite, the upper slopes of Mount Erebus are dominated by steeply dipping tephritic phonolite lava flows with large scale flow levees. A conspicuous break in slope at approximately 3,200 metres calls attention to a summit plateau representing a caldera, the summit caldera was created by an explosive VEI-6 eruption that occurred 18,000 ±7,000 years ago. It is filled with small volume tephritic phonolite and phonolite lava flows, in the center of the summit caldera is a small steep-sided cone composed primarily of decomposed lava bombs and a large deposit of anorthoclase crystals known as Erebus crystals. The active lava lake in this summit cone undergoes continuous degassing and these results demonstrated a complex upper-volcano conduit system with appreciable upper-volcano magma storage to the northwest of the lava lake at depths hundreds of meters below the surface. Mt. Erebus is notable for its numerous ice fumaroles – ice towers that form around gases that escape from vents in the surface. The ice caves associated with the fumaroles are dark, in alpine environments starved in organics. The life is sparse, mainly bacteria and fungi and this makes it of special interest for studying oligotrophs – organisms that can survive on minimal amounts of resources. It is thought that ice caves may exist on Mars – ice preserved under the surface in cave systems protected from the surface conditions. The caves on Erebus are of especial interest for astrobiology as most surface caves are influenced by human activities, the caves at Erebus are high altitude, yet accessible for study
19.
Volcano
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A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. Earths volcanoes occur because its crust is broken into 17 major, therefore, on Earth, volcanoes are generally found where tectonic plates are diverging or converging. This type of volcanism falls under the umbrella of plate hypothesis volcanism, Volcanism away from plate boundaries has also been explained as mantle plumes. These so-called hotspots, for example Hawaii, are postulated to arise from upwelling diapirs with magma from the boundary,3,000 km deep in the Earth. Volcanoes are usually not created where two plates slide past one another. Erupting volcanoes can pose hazards, not only in the immediate vicinity of the eruption. Historically, so-called volcanic winters have caused catastrophic famines, the word volcano is derived from the name of Vulcano, a volcanic island in the Aeolian Islands of Italy whose name in turn comes from Vulcan, the god of fire in Roman mythology. The study of volcanoes is called volcanology, sometimes spelled vulcanology, at the mid-oceanic ridges, two tectonic plates diverge from one another as new oceanic crust is formed by the cooling and solidifying of hot molten rock. Most divergent plate boundaries are at the bottom of the oceans, therefore, most volcanic activity is submarine, black smokers are evidence of this kind of volcanic activity. Where the mid-oceanic ridge is above sea-level, volcanic islands are formed, for example, subduction zones are places where two plates, usually an oceanic plate and a continental plate, collide. In this case, the plate subducts, or submerges under the continental plate forming a deep ocean trench just offshore. In a process called flux melting, water released from the subducting plate lowers the temperature of the overlying mantle wedge. This magma tends to be very viscous due to its high content, so it often does not reach the surface. When it does reach the surface, a volcano is formed, typical examples of this kind of volcano are Mount Etna and the volcanoes in the Pacific Ring of Fire. Because tectonic plates move across them, each volcano becomes dormant and is eventually re-formed as the plate advances over the postulated plume and this theory is currently under criticism, however. The most common perception of a volcano is of a mountain, spewing lava and poisonous gases from a crater at its summit, however. The features of volcanoes are more complicated and their structure. Some volcanoes have rugged peaks formed by lava domes rather than a summit crater while others have features such as massive plateaus
20.
Roald Amundsen
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Roald Engelbregt Gravning Amundsen was a Norwegian explorer of polar regions. He led the Antarctic expedition of 1910–12 which was the first to reach the South Pole, in 1926, he was the first expedition leader for the air expedition to the North Pole. Amundsen is recognized as the first person, without dispute, as having reached both poles and he is also known as having the first expedition to traverse the Northwest Passage in the Arctic. In June 1928, while taking part in a mission for the airship Italia. Amundsen was a key leader during the Heroic Age of Antarctic Exploration, in the class of Douglas Mawson, Robert Falcon Scott. Amundsen was born to a family of Norwegian shipowners and captains in Borge and his parents were Jens Amundsen and Hanna Sahlqvist. Roald was the son in the family. His mother wanted him to avoid the family trade and encouraged him to become a doctor. He promptly quit university for a life at sea, Amundsen had hidden a lifelong desire inspired by Fridtjof Nansens crossing of Greenland in 1888 and Franklins lost expedition. He decided on a life of exploration of wilderness places. Amundsen joined the Belgian Antarctic Expedition as first mate and this expedition, led by Adrien de Gerlache using the ship the RV Belgica, became the first expedition to winter in Antarctica. The Belgica, whether by mistake or design, became locked in the sea ice at 70°30′S off Alexander Island, the crew endured a winter for which they were poorly prepared. By Amundsens own estimation, the doctor for the expedition, the American Frederick Cook, probably saved the crew from scurvy by hunting for animals and feeding the crew fresh meat. In cases where citrus fruits are lacking, fresh meat from animals that make their own vitamin C contains enough of the vitamin to prevent scurvy and this was an important lesson for Amundsens future expeditions. In 1903, Amundsen led the first expedition to successfully traverse Canadas Northwest Passage between the Atlantic and Pacific oceans and he planned a small expedition of six men in a 45-ton fishing vessel, Gjøa, in order to have flexibility. His ship had relatively shallow draft and his technique was to use a small ship and hug the coast. Amundsen had the ship outfitted with a gasoline engine. They traveled via Baffin Bay, the Parry Channel and then south through Peel Sound, James Ross Strait, Simpson Strait and they spent two winters at King William Island in the harbor of what is today Gjoa Haven, Nunavut, Canada
21.
Bay of Whales
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The Bay of Whales was a natural ice harbor, or iceport, indenting the front of Ross Ice Shelf just north of Roosevelt Island, Antarctica. It is the southernmost point of open ocean not only of the Ross Sea, the Ross Sea extends much further south—as far as the Gould Coast, some 200 miles from the South Pole—but most of that area is covered by the Ross Ice Shelf rather than open sea. Ernest Shackleton named the feature on January 24,1908, during the Nimrod Expedition, during his quest for the South Pole, Norwegian explorer Roald Amundsen established a temporary base, which he named Framheim, at the Bay of Whales. The base was used between January 1911 – February 1912, a survey by the second Byrd expedition in 1934 determined that the feature lay at the junction of two separate ice systems, the movements of which are influenced by the presence of Roosevelt Island. Commander Glen Jacobsen, USN, who visited aboard the USS Atka in January 1955, the Bay of Whales was entirely eliminated in 1987 when 96 miles long Iceberg B-9 broke off from the Ross Ice Shelf. Ice pier Atka Iceport Erskine Iceport Godel Iceport Norsel Iceport This article incorporates public domain material from the United States Geological Survey document Whales, Bay of
22.
McMurdo Sound
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McMurdo Sound and its ice-clogged waters extends about 55 kilometres long and wide. The sound connects the Ross Sea to the north with the Ross Ice Shelf cavity to the south via Haskell Strait, the strait is largely covered by the McMurdo Ice Shelf. The Royal Society Range rises from sea level to 4,205 metres on the western shoreline, Ross Island, an historic jumping-off point for polar explorers, designates the eastern boundary. The active volcano Mt Erebus at 3,794 metres dominates Ross Island, Antarcticas largest scientific base, the United States McMurdo Station, as well as the New Zealand Scott Base are on the southern shore of the island. Less than 10 percent of McMurdo Sounds shoreline is free of ice and it is the southernmost navigable body of water in the world. Captain James Clark Ross discovered this sound, which is about 1,300 kilometres from the South Pole, in February 1841, the sound today serves as a resupply route for cargo ships and for airplanes that land on the floating ice airstrips near the McMurdo Station. However, McMurdo Station’s continuous occupation by human beings since 1957/58 has dirtied the harbor of Winter Quarters Bay, the pack ice that girdles the shoreline at Winter Quarters Bay and elsewhere in the sound presents a formidable obstacle to surface ships. Vessels require ice-strengthened hulls and often have to rely upon escort by icebreakers, such extreme sea conditions have limited access by tourists, who otherwise are appearing in increasing numbers in the open waters of the Antarctic Peninsula. The few tourists who reach the McMurdo Sound find spectacular scenery with wildlife to be seen, including whales, seals, Adelie penguins. Cold circumpolar currents of the Southern Ocean reduce the flow of warm South Pacific or South Atlantic waters reaching McMurdo Sound, bitter katabatic winds spilling down from the Antarctic polar plateau into McMurdo Sound demonstrate Antarcticas status as the coldest and windiest continent in the world. The McMurdo Sound freezes over with sea ice about 3 metres thick during the winter, the Antarctic summer causes the pack ice to break up. Wind and currents may push the ice northward into the Ross Sea, temperatures during the dark winter months at McMurdo Station have dropped as low as −51 °C. However, December and January are the warmest months, with highs at −1 °C. McMurdo Sounds role as a strategic waterway dates back to early 20th century Antarctic exploration, British explorers Ernest Shackleton and Robert Scott built bases on the sounds shoreline as jumping-off points for their overland expeditions to the South Pole. McMurdo Sounds logistic importance continues today, aircraft transporting cargo and passengers land upon frozen runways at Williams Field on the McMurdo Ice Shelf. Moreover, the annual sealift of a ship and fuel tanker rely upon the sound as a supply route to the continents largest base. Both the U. S. base and New Zealands nearby Scott Base are on the tip of Ross Island. Ross Island is the southmost piece of land in Antarctica that is accessible by ship, in addition, the harbor at McMurdos Winter Quarters Bay is the worlds southmost seaport
23.
Continental shelf
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The continental shelf is an underwater landmass which extends from a continent, resulting in an area of relatively shallow water known as a shelf sea. Much of the shelves were exposed during glacial periods and interglacial periods, the shelf surrounding an island is known as an insular shelf. The continental margin, between the shelf and the abyssal plain, comprises a steep continental slope followed by the flatter continental rise. Sediment from the continent above cascades down the slope and accumulates as a pile of sediment at the base of the slope, extending as far as 500 km from the slope, it consists of thick sediments deposited by turbidity currents from the shelf and slope. The continental rises gradient is intermediate between the slope and the shelf, on the order of 0. 5–1°, the largest shelf – the Siberian Shelf in the Arctic Ocean – stretches to 1,500 kilometers in width. The South China Sea lies over another extensive area of shelf, the Sunda Shelf, which joins Borneo, Sumatra. Other familiar bodies of water that overlie continental shelves are the North Sea, the average width of continental shelves is about 80 km. The depth of the shelf also varies, but is limited to water shallower than 150 m. The slope of the shelf is quite low, on the order of 0. 5°, vertical relief is also minimal. Though the continental shelf is treated as a province of the ocean, it is not part of the deep ocean basin proper. Passive continental margins such as most of the Atlantic coasts have wide and shallow shelves, active continental margins have narrow, relatively steep shelves, due to frequent earthquakes that move sediment to the deep sea. The shelf usually ends at a point of increasing slope, the sea floor below the break is the continental slope. Below the slope is the rise, which finally merges into the deep ocean floor. The continental shelf and the slope are part of the continental margin, the shelf area is commonly subdivided into the inner continental shelf, mid continental shelf, and outer continental shelf, each with their specific geomorphology and marine biology. The character of the shelf changes dramatically at the shelf break, with a few exceptions, the shelf break is located at a remarkably uniform depth of roughly 140 m, this is likely a hallmark of past ice ages, when sea level was lower than it is now. The continental slope is steeper than the shelf, the average angle is 3°. The slope is cut with submarine canyons. The physical mechanisms involved in forming these canyons were not well understood until the 1960s, the continental shelves are covered by terrigenous sediments, that is, those derived from erosion of the continents
24.
Calcium carbonate
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Calcium carbonate is a chemical compound with the formula CaCO3. It is a substance found in rocks as the minerals calcite and aragonite and is the main component of pearls and the shells of marine organisms, snails. Calcium carbonate is the ingredient in agricultural lime and is created when calcium ions in hard water react with carbonate ions to create limescale. It is medicinally used as a supplement or as an antacid. Calcium carbonate shares the properties of other carbonates. CaCO3 + CO2 + H2O → Ca2 This reaction is important in the erosion of rock, forming caverns. An unusual form of calcium carbonate is the hexahydrate, ikaite, ikaite is stable only below 6 °C. The vast majority of calcium used in industry is extracted by mining or quarrying. Pure calcium carbonate, can be produced from a quarried source. Alternatively, calcium carbonate is prepared from calcium oxide, other forms can be prepared, the denser, orthorhombic λ-CaCO3 and μ-CaCO3, occurring as the mineral vaterite. The aragonite form can be prepared by precipitation at temperatures above 85 °C, calcite contains calcium atoms coordinated by 6 oxygen atoms, in aragonite they are coordinated by 9 oxygen atoms. The vaterite structure is not fully understood, magnesium carbonate MgCO3 has the calcite structure, whereas strontium and barium carbonate adopt the aragonite structure, reflecting their larger ionic radii. Calcite, aragonite and vaterite are pure calcium carbonate minerals, industrially important source rocks which are predominantly calcium carbonate include limestone, chalk, marble and travertine. Eggshells, snail shells and most seashells are predominantly calcium carbonate, oyster shells have enjoyed recent recognition as a source of dietary calcium, but are also a practical industrial source. While not practical as a source, dark green vegetables such as broccoli. Beyond Earth, strong evidence suggests the presence of Calcium carbonate on Mars, signs of Calcium Carbonate have been detected at more than one location. This provides some evidence for the past presence of liquid water, Carbonate is found frequently in geologic settings and constitute an enormous carbon reservoir. Calcium carbonate occurs as aragonite, calcite and dolomite, the carbonate minerals form the rock types, limestone, chalk, marble, travertine, tufa, and others
25.
Limestone
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Limestone is a sedimentary rock, composed mainly of skeletal fragments of marine organisms such as coral, forams and molluscs. Its major materials are the minerals calcite and aragonite, which are different crystal forms of calcium carbonate, about 10% of sedimentary rocks are limestones. The solubility of limestone in water and weak acid solutions leads to karst landscapes, most cave systems are through limestone bedrock. The first geologist to distinguish limestone from dolomite was Belsazar Hacquet in 1778, like most other sedimentary rocks, most limestone is composed of grains. Most grains in limestone are skeletal fragments of organisms such as coral or foraminifera. Other carbonate grains comprising limestones are ooids, peloids, intraclasts and these organisms secrete shells made of aragonite or calcite, and leave these shells behind when they die. Limestone often contains variable amounts of silica in the form of chert or siliceous skeletal fragment, some limestones do not consist of grains at all, and are formed completely by the chemical precipitation of calcite or aragonite, i. e. travertine. Secondary calcite may be deposited by supersaturated meteoric waters and this produces speleothems, such as stalagmites and stalactites. Another form taken by calcite is oolitic limestone, which can be recognized by its granular appearance, the primary source of the calcite in limestone is most commonly marine organisms. Some of these organisms can construct mounds of rock known as reefs, below about 3,000 meters, water pressure and temperature conditions cause the dissolution of calcite to increase nonlinearly, so limestone typically does not form in deeper waters. Limestones may also form in lacustrine and evaporite depositional environments, calcite can be dissolved or precipitated by groundwater, depending on several factors, including the water temperature, pH, and dissolved ion concentrations. Calcite exhibits a characteristic called retrograde solubility, in which it becomes less soluble in water as the temperature increases. Impurities will cause limestones to exhibit different colors, especially with weathered surfaces, Limestone may be crystalline, clastic, granular, or massive, depending on the method of formation. Crystals of calcite, quartz, dolomite or barite may line small cavities in the rock, when conditions are right for precipitation, calcite forms mineral coatings that cement the existing rock grains together, or it can fill fractures. Travertine is a banded, compact variety of limestone formed along streams, particularly there are waterfalls. Calcium carbonate is deposited where evaporation of the leaves a solution supersaturated with the chemical constituents of calcite. Tufa, a porous or cellular variety of travertine, is found near waterfalls, coquina is a poorly consolidated limestone composed of pieces of coral or shells. During regional metamorphism that occurs during the building process, limestone recrystallizes into marble
26.
Argillite
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Argillite may also refer to Argillite, Kentucky. An argillite is a sedimentary rock composed predominantly of indurated clay particles. Argillaceous rocks are basically lithified muds and oozes and they contain variable amounts of silt-sized particles. The argillites grade into shale when the fissile layering typical of shale is developed, another name for poorly lithified argillites is mudstone. These rocks, although variable in composition, are high in aluminium and silica with variable alkali. The term pelitic or pelite is often applied to these sediments, metamorphism of argillites produces slate, phyllite, and pelitic schist. The Belt Supergroup, an assemblage of rocks of late Precambrian age, includes thick sequences of argillite and it is exposed primarily in western Montana, including the Bitterroot Valley and Bitterroot Mountains, the Missoula area, Flathead Lake, and Glacier National Park, and in northern Idaho. There are also minor occurrences in northwestern Washington and western Wyoming, the Haida carvings of along the coast of British Columbia are notable aboriginal art treasures created from a type of a hard, fine black silt argillite, sometimes called black slate. The black slate occurs only at a quarry on a Slatechuck Mountain in the basin of Slatechuck Creek. At one time, around 1900, it was shipped to Victoria for manufacturing and this artwork has been of high quality and prized around the world since the Haida first began carving it to sell to sailors around 1800, modern Haida carvers continue the tradition. Mudrock Catlinite Lutite R. V. Dietrich,2005, Gemrocks, museum of Civilization Haida argillite gallery BC Govt MINFILE report, includes history and geological data. Dauzères, Alexandre,2004, Ten Years of Argillite Study, Procedia Earth and Planetary Science USGS argillite
27.
Siltstone
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Siltstone is a sedimentary rock which has a grain size in the silt range, finer than sandstone and coarser than claystones. Siltstone is a sedimentary rock. As its name implies, it is composed of silt sized particles. Siltstones differ significantly from sandstones due to their smaller pores and higher propensity for containing a significant clay fraction, although often mistaken as a shale, siltstone lacks the fissility and laminations which are typical of shale. Unless the siltstone is fairly shaly, stratification is likely to be obscure, mudstone or shale are rocks that contain mud, which is material that has a range of silt and clay. Siltstone is differentiated by having a majority silt, not clay, folk, R. L.1965, Petrology of sedimentary rocks PDF version. 2nd ed.1981, ISBN 0-914696-14-9 Williams, Howel, Francis J. Turner and Charles M. Gilbert,1954, Petrography, W. H. Freeman
28.
Sandstone
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Sandstone is a clastic sedimentary rock composed mainly of sand-sized minerals or rock grains. Most sandstone is composed of quartz or feldspar because these are the most common minerals in the Earths crust, like sand, sandstone may be any color, but the most common colors are tan, brown, yellow, red, grey, pink, white, and black. Since sandstone beds often form highly visible cliffs and other topographic features, quartz-bearing sandstone is converted into quartzite through heating and pressure, usually related to tectonic compression within orogenic belts. They are formed from cemented grains that may either be fragments of a rock or be mono-minerallic crystals. The cements binding these grains together are typically calcite, clays, grain sizes in sands are defined within the range of 0.0625 mm to 2 mm. The formation of sandstone involves two principal stages, first, a layer or layers of sand accumulates as the result of sedimentation, either from water or from air. Typically, sedimentation occurs by the settling out from suspension. The most common cementing materials are silica and calcium carbonate, which are derived either from dissolution or from alteration of the sand after it was buried. Colours will usually be tan or yellow, a predominant additional colourant in the southwestern United States is iron oxide, which imparts reddish tints ranging from pink to dark red, with additional manganese imparting a purplish hue. Red sandstones are seen in the Southwest and West of Britain, as well as central Europe. The regularity of the latter favours use as a source for masonry, either as a building material or as a facing stone. These physical properties allow the grains to survive multiple recycling events. Quartz grains evolve from rock, which are felsic in origin. Feldspathic framework grains are commonly the second most abundant mineral in sandstones, Feldspar can be divided into two smaller subdivisions, alkali feldspars and plagioclase feldspars. The different types of feldspar can be distinguished under a petrographic microscope, below is a description of the different types of feldspar. Alkali feldspar is a group of minerals in which the composition of the mineral can range from KAlSi3O8 to NaAlSi3O8. Plagioclase feldspar is a group of solid solution minerals that range in composition from NaAlSi3O8 to CaAl2Si2O8. Lithic framework grains are pieces of ancient source rock that have yet to weather away to individual mineral grains, accessory minerals are all other mineral grains in a sandstone, commonly these minerals make up just a small percentage of the grains in a sandstone
29.
Skelton Glacier
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Skelton Glacier is a large glacier flowing from the polar plateau into the Ross Ice Shelf at Skelton Inlet on the Hillary Coast, south of Victoria Land, Antarctica. Named after the Skelton Inlet by the New Zealand party of the CTAE, allison Glacier descends from the west slopes of Royal Society Range into Skelton Glacier. List of glaciers in the Antarctic 1, the story of the New Zealand Party of the Trans-Antarctic Expedition. R. E. Owen, Government Printer, Wellington, New Zealand, New Zealand and the Antarctic by L. B. Quatermain. A. R. Shearer, Government Printer, Wellington, New Zealand and this article incorporates public domain material from the United States Geological Survey document Skelton Glacier
30.
Greywacke
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It is a texturally immature sedimentary rock generally found in Palaeozoic strata. The larger grains can be sand- to gravel-sized, and matrix materials generally constitute more than 15% of the rock by volume, the term greywacke can be confusing, since it can refer to either the immature aspect of the rock or the fine-grained component of the rock. Geologists now attribute its formation to submarine avalanches or strong turbidity currents and these actions churn sediment and cause mixed-sediment slurries, in which the rocks may exhibit a variety of sedimentary features. They also occur in association with black shales of deep sea origin, greywackes are mostly grey, brown, yellow or black, dull-colored sandy rocks which may occur in thick or thin beds along with shales and limestones. Among other minerals found in them are biotite, chlorite, tourmaline, epidote, apatite, garnet, hornblende, augite, sphene, the cementing material may be siliceous or argillaceous and is sometimes calcareous. As a rule greywackes are not fossiliferous, but organic remains may be common in the finer beds associated with them and their component particles are usually not very rounded or polished, and the rocks have often been considerably indurated by recrystallization, such as the introduction of interstitial silica. In some districts the greywackes are cleaved, but they show phenomena of this much less perfectly than the slates. Some varieties include feldspathic greywacke, which is rich in feldspar, and lithic greywacke and their essential features are their gritty character and their complex composition. By increasing metamorphism, greywackes frequently pass into mica-schists, chloritic schists, Greywacke zone Torlesse Greywacke This article incorporates text from a publication now in the public domain, Chisholm, Hugh, ed. Greywacke. National Park Service site Presidio Franciscan Greywacke/Shales
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Beardmore Glacier
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The Beardmore Glacier in Antarctica is one of the largest valley glaciers in the world, being 200 km long and having a width of 40 km. The glacier is one of the passages through the Transantarctic Mountains to the great polar plateau beyond. The glacier was discovered and climbed by Ernest Shackleton during his Nimrod Expedition of 1908. Although Shackleton turned back before reaching the South Pole, he established the first proven route towards the pole and, in doing so, in 1911–1912, Captain Scott and his Terra Nova Expedition team reached the South Pole by similarly climbing the Beardmore. However, they reached the pole a month after Roald Amundsen and his team, Beardmore Glacier was named by Shackleton after Sir William Beardmore, a Scottish industrialist and expedition sponsor born in 1856. In 2016 the first beetle fossils, in the form of wing-cases of Balls Antarctic tundra beetle,14 to 20 million years old, were found on the glacier. List of glaciers in the Antarctic This article incorporates public domain material from the United States Geological Survey document Beardmore Glacier
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Granite
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Granite is a common type of felsic intrusive igneous rock that is granular and phaneritic in texture. Granites can be white, pink, or gray in color. The word granite comes from the Latin granum, a grain, in reference to the structure of such a holocrystalline rock. By definition, granite is a rock with at least 20% quartz. The term granitic means granite-like and is applied to granite and a group of igneous rocks with similar textures and slight variations in composition. Occasionally some individual crystals are larger than the groundmass, in case the texture is known as porphyritic. A granitic rock with a texture is known as a granite porphyry. Granitoid is a general, descriptive field term for lighter-colored, coarse-grained igneous rocks, petrographic examination is required for identification of specific types of granitoids. The extrusive igneous rock equivalent of granite is rhyolite, Granite is nearly always massive, hard and tough, and therefore it has gained widespread use throughout human history, and more recently as a construction stone. The average density of granite is between 2.65 and 2.75 g/cm3, its compressive strength usually lies above 200 MPa, and its viscosity near STP is 3–6 •1019 Pa·s. The melting temperature of dry granite at ambient pressure is 1215–1260 °C, it is reduced in the presence of water. Granite has poor primary permeability, but strong secondary permeability, true granite according to modern petrologic convention contains both plagioclase and alkali feldspars. When a granitoid is devoid or nearly devoid of plagioclase, the rock is referred to as alkali feldspar granite, when a granitoid contains less than 10% orthoclase, it is called tonalite, pyroxene and amphibole are common in tonalite. A granite containing both muscovite and biotite micas is called a binary or two-mica granite, two-mica granites are typically high in potassium and low in plagioclase, and are usually S-type granites or A-type granites. A worldwide average of the composition of granite, by weight percent, based on 2485 analyses. Much of it was intruded during the Precambrian age, it is the most abundant basement rock that underlies the relatively thin veneer of the continents. Outcrops of granite tend to form tors and rounded massifs, granites sometimes occur in circular depressions surrounded by a range of hills, formed by the metamorphic aureole or hornfels. Granite often occurs as small, less than 100 km² stock masses
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Polynya
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A polynya /pəˈlɪnjə/ is an area of open water surrounded by sea ice. It is now used as term for an area of unfrozen sea within the ice pack. It is a loanword from Russian, полынья Russian pronunciation, which refers to an ice hole. In past decades, for example, some polynyas, such as the Weddell Polynya, have lasted over multiple winters and this reduces ice production and may stop it altogether. Latent heat polynya, is formed through the action of wind or ocean currents which act to drive ice away from a fixed boundary, such as a coastline, fast ice. The polynya forms initially by the first year pack ice being driven away from the coast and this new ice is then also herded downwind toward the first year pack ice. When it reaches the ice the new ice is consolidated onto the pack ice. The latent heat polynya is the water region between the coast and the ice pack. Latent heat polynyas are regions of ice production and therefore are possible sites of dense water production in both polar regions. The high ice production rates within these polynyas leads to an amount of brine rejection into the surface waters. This salty water then sinks and mixes to possibly form new water masses and it is an open question as to whether the polynyas of the Arctic can produce enough dense water to form a major portion of the dense water required to drive the thermohaline circulation. Some polynyas, such as the North Water Polynya between Canada and Greenland occur seasonally at the time and place each year. Because animals can adapt their strategies to this regularity, these types of polynyas are of special ecological research significance. In winter, marine mammals such as walruses, narwhals and belugas that do not migrate south, polar bears are known to be able to swim as far as 65 kilometres across open waters of a polynya. The presence of polynyas in McMurdo Sound in the Antarctic provides an area where penguins can feed. When submarines of the U. S. Navy made expeditions to the North Pole in the 1950s and 60s, there was a significant concern about surfacing through the thick pack ice of the Arctic Ocean. In 1962, both the USS Skate and USS Seadragon surfaced within the same, large polynya near the North Pole, lead North Water Polynya Weddell Polynya International North Water Polynya Study Polynya north of Alaska at NASA Earth Observatory
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Sea
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A sea is a large body of salt water that is surrounded in whole or in part by land. More broadly, the sea is the system of Earths salty. The sea moderates Earths climate and has important roles in the cycle, carbon cycle. Although the sea has been traveled and explored since prehistory, the scientific study of the sea—oceanography—dates broadly to the British Challenger expedition of the 1870s. Owing to the present state of continental drift, the Northern Hemisphere is now equally divided between land and sea but the South is overwhelmingly oceanic. Salinity in the ocean is generally in a narrow band around 3. 5% by mass, although this can vary in more landlocked waters, near the mouths of large rivers. About 85% of the solids in the sea are sodium chloride. Deep-sea currents are produced by differences in salinity and temperature, surface currents are formed by the friction of waves produced by the wind and by tides, the changes in local sea level produced by the gravity of the Moon and Sun. The direction of all of these is governed by surface and submarine land masses, former changes in sea levels have left continental shelves, shallow areas in the sea close to land. The most diverse areas surround great tropical coral reefs, whaling in the deep sea was once common but whales dwindling numbers prompted international conservation efforts and finally a moratorium on most commercial hunting. Life may have started there and aquatic microbial mats are generally credited with the oxygenation of Earths atmosphere, the sea is an essential aspect of human trade, travel, mineral extraction, and power generation. It is the scene of activities including swimming, diving, surfing. However, population growth, industrialization, and intensive farming have all contributed to marine pollution. Atmospheric carbon dioxide is being absorbed in increasing amounts, lowering its pH in a known as ocean acidification. The shared nature of the sea has made overfishing an increasing problem, both senses of sea date to Old English, the larger sense has required a definite article since Early Middle English. Seas are generally larger than lakes and contain salt water, while the defining elements of size and being bounded are generally used, there is no formally accepted technical definition of sea among oceanographers. In international law, the United Nations Convention on the Law of the Sea states that all the ocean is the sea. Earth is the known planet with seas of liquid water on its surface, although Mars possesses ice caps
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Earth
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Earth, otherwise known as the World, or the Globe, is the third planet from the Sun and the only object in the Universe known to harbor life. It is the densest planet in the Solar System and the largest of the four terrestrial planets, according to radiometric dating and other sources of evidence, Earth formed about 4.54 billion years ago. Earths gravity interacts with objects in space, especially the Sun. During one orbit around the Sun, Earth rotates about its axis over 365 times, thus, Earths axis of rotation is tilted, producing seasonal variations on the planets surface. The gravitational interaction between the Earth and Moon causes ocean tides, stabilizes the Earths orientation on its axis, Earths lithosphere is divided into several rigid tectonic plates that migrate across the surface over periods of many millions of years. About 71% of Earths surface is covered with water, mostly by its oceans, the remaining 29% is land consisting of continents and islands that together have many lakes, rivers and other sources of water that contribute to the hydrosphere. The majority of Earths polar regions are covered in ice, including the Antarctic ice sheet, Earths interior remains active with a solid iron inner core, a liquid outer core that generates the Earths magnetic field, and a convecting mantle that drives plate tectonics. Within the first billion years of Earths history, life appeared in the oceans and began to affect the Earths atmosphere and surface, some geological evidence indicates that life may have arisen as much as 4.1 billion years ago. Since then, the combination of Earths distance from the Sun, physical properties, in the history of the Earth, biodiversity has gone through long periods of expansion, occasionally punctuated by mass extinction events. Over 99% of all species that lived on Earth are extinct. Estimates of the number of species on Earth today vary widely, over 7.4 billion humans live on Earth and depend on its biosphere and minerals for their survival. Humans have developed diverse societies and cultures, politically, the world has about 200 sovereign states, the modern English word Earth developed from a wide variety of Middle English forms, which derived from an Old English noun most often spelled eorðe. It has cognates in every Germanic language, and their proto-Germanic root has been reconstructed as *erþō, originally, earth was written in lowercase, and from early Middle English, its definite sense as the globe was expressed as the earth. By early Modern English, many nouns were capitalized, and the became the Earth. More recently, the name is simply given as Earth. House styles now vary, Oxford spelling recognizes the lowercase form as the most common, another convention capitalizes Earth when appearing as a name but writes it in lowercase when preceded by the. It almost always appears in lowercase in colloquial expressions such as what on earth are you doing, the oldest material found in the Solar System is dated to 4. 5672±0.0006 billion years ago. By 4. 54±0.04 Gya the primordial Earth had formed, the formation and evolution of Solar System bodies occurred along with the Sun
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Pollution
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Pollution is the introduction of contaminants into the natural environment that cause adverse change. Pollution can take the form of chemical substances or energy, such as noise, pollutants, the components of pollution, can be either foreign substances/energies or naturally occurring contaminants. Pollution is often classed as point source or nonpoint source pollution, Air pollution has always accompanied civilizations. Pollution started from prehistoric times when man created the first fires, metal forging appears to be a key turning point in the creation of significant air pollution levels outside the home. The burning of coal and wood, and the presence of horses in concentrated areas made the cities the cesspools of pollution. The Industrial Revolution brought an infusion of untreated chemicals and wastes into local streams that served as the water supply, king Edward I of England banned the burning of sea-coal by proclamation in London in 1272, after its smoke became a problem. But the fuel was so common in England that this earliest of names for it was acquired because it could be carted away from some shores by the wheelbarrow and it was the industrial revolution that gave birth to environmental pollution as we know it today. London also recorded one of the extreme cases of water quality problems with the Great Stink on the Thames of 1858. Pollution issues escalated as population growth far exceeded view ability of neighborhoods to handle their waste problem, reformers began to demand sewer systems, and clean water. In 1870, the conditions in Berlin were among the worst in Europe. There were no toilets in the streets or squares. Visitors, especially women, often became desperate when nature called, in the public buildings the sanitary facilities were unbelievably primitive. As a metropolis, Berlin did not emerge from a state of barbarism into civilization until after 1870. Chicago and Cincinnati were the first two American cities to enact laws ensuring cleaner air in 1881, as historian Martin Melosi notes, The generation that first saw automobiles replacing the horses saw cars as miracles of cleanliness. By the 1940s, however, automobile-caused smog was an issue in Los Angeles. Other cities followed around the country early in the 20th century. Extreme smog events were experienced by the cities of Los Angeles and Donora, Pennsylvania in the late 1940s, Air pollution would continue to be a problem in England, especially later during the industrial revolution, and extending into the recent past with the Great Smog of 1952. Awareness of atmospheric pollution spread widely after World War II, with fears triggered by reports of fallout from atomic warfare. Then a non-nuclear event, The Great Smog of 1952 in London and this prompted some of the first major modern environmental legislation, The Clean Air Act of 1956
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Invasive species
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One study pointed out widely divergent perceptions of the criteria for invasive species among researchers and concerns with the subjectivity of the term invasive. Such invasive species may be either plants or animals and may disrupt by dominating a region, wilderness areas, particular habitats and this includes non-native invasive plant species labeled as exotic pest plants and invasive exotics growing in native plant communities. It has been used in this sense by government organizations as well as groups such as the International Union for Conservation of Nature. The European Union defines Invasive Alien Species as those that are, firstly, outside their natural distribution area and it is also used by land managers, botanists, researchers, horticulturalists, conservationists, and the public for noxious weeds. The kudzu vine, Andean Pampas grass, and yellow starthistle are examples, an alternate usage broadens the term to include indigenous or native species along with non-native species, that have colonized natural areas. Deer are an example, considered to be overpopulating their native zones and adjacent suburban gardens, by some in the Northeastern, sometimes the term is used to describe a non-native or introduced species that has become widespread. However, not every introduced species has adverse effects on the environment, a nonadverse example is the common goldfish, which is found throughout the United States, but rarely achieves high densities. Scientists include species and ecosystem factors among the mechanisms that when combined, while all species compete to survive, invasive species appear to have specific traits or specific combinations of traits that allow them to outcompete native species. In some cases, the competition is about rates of growth, in other cases, species interact with each other more directly. Researchers disagree about the usefulness of traits as invasiveness markers, one study found that of a list of invasive and noninvasive species, 86% of the invasive species could be identified from the traits alone. Another study found invasive species tended to have only a subset of the presumed traits. Repeated patterns of movement, such as ships sailing to and from ports or cars driving up. An introduced species might become if it can outcompete native species for resources such as nutrients, light, physical space, water. If these species evolved under great competition or predation, then the new environment may host fewer able competitors, allowing the invader to proliferate quickly. Ecosystems in which are being used to their fullest capacity by native species can be modeled as zero-sum systems in which any gain for the invader is a loss for the native, however, such unilateral competitive superiority is not the rule. For example, barbed goatgrass was introduced to California on serpentine soils, which have low water-retention, low nutrient levels, a high magnesium/calcium ratio, and possible heavy metal toxicity. Plant populations on these soils tend to low density, but goatgrass can form dense stands on these soils. Some species, like Kalanchoe daigremontana, produce allelopathic compounds, that might have an effect on competing species
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Emperor penguin
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The emperor penguin is the tallest and heaviest of all living penguin species and is endemic to Antarctica. The male and female are similar in plumage and size, reaching 122 cm in height, the dorsal side and head are black and sharply delineated from the white belly, pale-yellow breast and bright-yellow ear patches. Like all penguins it is flightless, with a streamlined body and its diet consists primarily of fish, but can also include crustaceans, such as krill, and cephalopods, such as squid. In hunting, the species can remain submerged up to 18 minutes, the only penguin species that breeds during the Antarctic winter, emperor penguins trek 50–120 km over the ice to breeding colonies which may include thousands of individuals. The female lays an egg, which is incubated by the male while the female returns to the sea to feed, parents subsequently take turns foraging at sea. The lifespan is typically 20 years in the wild, although observations suggest that individuals may live to 50 years of age. Emperor penguins were described in 1844 by English zoologist George Robert Gray and its specific name is in honour of the German naturalist Johann Reinhold Forster, who accompanied Captain James Cook on his second voyage and officially named five other penguin species. Forster may have been the first person to sight the penguins in 1773–74, he recorded a sighting of what he believed to be A. patagonicus but, given the location, may well have been A. forsteri. Together with the similarly coloured but smaller king penguin, the penguin is one of two extant species in the genus Aptenodytes. Fossil evidence of a third species—Ridgens penguin —has been found in records from the late Pliocene. Studies of penguin behaviour and genetics have proposed that the genus Aptenodytes is basal, in other words, mitochondrial and nuclear DNA evidence suggests this split occurred around 40 million years ago. Adult emperor penguins stand up to 110–130 cm tall, the weight ranges from 22.7 to 45.4 kg and varies by sex, with males weighing more than females. It is the fifth heaviest living species, after only the larger varieties of ratite. The weight also varies by season, as male and female penguins lose substantial mass while raising hatchlings and incubating their egg. A male emperor penguin must withstand the Antarctic cold for more two months to protect his egg from extreme cold. During this entire time he doesnt eat anything, most male penguins will lose about 12 kg while they wait for their chicks to hatch. The mean weight of males at the start of the season is 38 kg. After the breeding season this drops to 23 kg for both sexes, like all penguin species, emperor penguins have streamlined bodies to minimize drag while swimming, and wings that are more like stiff, flat flippers
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Antarctic petrel
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The Antarctic petrel is a boldly marked dark brown and white petrel, found in Antarctica, most commonly in the Ross and Weddell seas. They eat Antarctic krill, fish, and small squid and they feed while swimming but can dive from both the surface and the air. The Antarctic petrel is the known species in the genus Thalassoica, and is a member of the family Procellariidae. First, they have passages that attach to the upper bill called naricorns. Although the nostrils on the petrels are on the top of the upper bill, the bills of Procellariiformes are also unique in that they are split into between seven and nine horny plates. On petrels, one of these forms the hooked portion of the upper bill. They produce an oil made up of wax esters and triglycerides that is stored in the proventriculus. This can be sprayed out of their mouths as a defence against predators and as a rich food source for chicks. Finally, they also have a gland that is situated above the nasal passage and helps desalinate their bodies. It excretes a high saline solution from their nose, the word petrel is derived from St. Peter and the story of his walking on water. This is in reference to the habit of appearing to run on the water to take off. The adult Antarctic petrel has a head, sides, throat. Their bill is black and their feet are yellow and their underparts are white and their tail and secondaries on their wings are white with brown tips. The Antarctic petrel, as its name implies, lives and breeds in the Southern Ocean and this petrel has an occurrence range of 35,200,000 km2 and between 10 and 20 million adult birds based on a 2009 estimate. With these numbers and the range, this bird has been classified as least concern. Antarctic Petrel Thalassoica antarctica - BirdLife Species Factsheet, the BirdLife checklist of the birds of the world, with conservation status and taxonomic sources. Systema Naturae 2000 / Classification - Genus Thalassoica-, the Clements Checklist of the Birds of the World. In Hutchins, Michael, Jackson, Jerome A. Bock, Walter J. Olendorf,8, Birds I, Tinamous and Ratites to Hoatzins
Media related to Ross Sea at Wikimedia Commons
