Borkum ( Low German : Borkum, Börkum ) is an island and a municipality in the Leer District in Lower Saxony , northwestern Germany . It is situated east of Rottumeroog and west of Juist .
31-852: Borkum is bordered to the west by the Westerems strait (which forms the border with the Netherlands), to the east by the Osterems strait, to the north by the North Sea , and to the south by the Wadden Sea . It is the largest and westernmost of the East Frisian Islands in the North Sea , due north of the Dutch province of Groningen . The island was formed in 1863 by two previously separate islands which were still separated by
62-428: A habitat for mobile benthic organisms. These biotic reef types take on additional names depending upon how the reef lies in relation to the land, if any. Reef types include fringing reefs , barrier reefs , and atolls . A fringing reef is a reef that is attached to an island. Whereas, a barrier reef forms a calcareous barrier around an island, resulting in a lagoon between the shore and the reef. Conversely, an atoll
93-523: A shallow water. The seam between the former eastern and western parts is called Tüskendör ("through in between"). Borkum is the only East Frisian island that is under the influence of the North Sea all year round thanks to its 30 km (19 mi) distance from the mainland. The maritime climate is influenced by the Gulf Stream and the west wind zone with correspondingly high humidity throughout
124-668: A skeletal framework. A microbial mound might be built exclusively or primarily by cyanobacteria . Examples of biostromes formed by cyanobacteria occur in the Great Salt Lake in Utah , United States, and in Shark Bay on the coast of Western Australia . Cyanobacteria do not have skeletons, and individual organisms are microscopic. However, they can encourage the precipitation or accumulation of calcium carbonate to produce distinct sediment bodies in composition that have relief on
155-530: Is a ridge or shoal of rock, coral , or similar relatively stable material lying beneath the surface of a natural body of water. Many reefs result from natural, abiotic (non-living) processes such as deposition of sand or wave erosion planning down rock outcrops. However, reefs such as the coral reefs of tropical waters are formed by biotic (living) processes, dominated by corals and coralline algae . Artificial reefs , such as shipwrecks and other man-made underwater structures, may occur intentionally or as
186-470: Is a ring reef with no land present. The reef front, facing the ocean, is a high energy locale. Whereas, the internal lagoon will be at a lower energy with fine grained sediments. Both mounds and reefs are considered to be varieties of organosedimentary buildups, which are sedimentary features, built by the interaction of organisms and their environment. These interactions have a synoptic relief and whose biotic composition differs from that found on and beneath
217-401: Is typically reserved for much larger, wider features of the marine environment. There are exceptions, with straits being called canals; Pearse Canal , for example. Straits are the converse of isthmuses . That is, while a strait lies between two land masses and connects two large areas of ocean, an isthmus lies between two areas of ocean and connects two large land masses. Some straits have
248-622: The Old Norse word rif, meaning "rib" or "reef". Rif comes from the Proto-Germanic term ribją meaning "rib". Reefs may be classified in terms of their origin, geographical location, depth, and topography . For example a tropical coral fringing reef, or a temperate rocky intertidal reef. A variety of biotic reef types exists, including oyster reefs and sponge reefs , but the most massive and widely distributed are tropical coral reefs . Although corals are major contributors to
279-476: The Rigs-to-Reefs program), scuttling ships , or by deploying rubble or construction debris . Other artificial reefs are purpose built (e.g. the reef balls ) from PVC or concrete. Shipwrecks become artificial reefs on the seafloor. Regardless of construction method, artificial reefs generally provide stable hard surfaces where algae and invertebrates such as barnacles , corals, and oysters attach;
310-468: The Suez Canal . Although rivers and canals often provide passage between two large lakes, and these seem to suit the formal definition of strait, they are not usually referred to as such. Rivers and often canals, generally have a directional flow tied to changes in elevation, whereas straits often are free flowing in either direction or switch direction, maintaining the same elevation. The term strait
341-531: The Elder , Borkum by the time of Charlemagne was part of a larger island called Bant , which consisted of the present day islands of Borkum, Juist , and the western part of Norderney . In 1484, Bant passed to the Earls of East Frisia , who developed trade, and the island became known as a centre of piracy and whaling. By 1781, violent storms in the 18th century divided Bant into three islands. As whaling decreased,
SECTION 10
#1732802346161372-548: The Tüskendör area. Borkum is served by ferries from Emden , Germany and Eemshaven , the Netherlands. The Borkumer Kleinbahn narrow-gauge railway connects the harbour and the town of Borkum. Strait A strait is a water body connecting two seas or two water basins. While the landform generally constricts the flow, the surface water still flows, for the most part, at the same elevation on both sides and through
403-481: The adjacent unconsolidated surface with varying relief. They can be found in depth ranges from intertidal to deep water and provide a substrate for a large range of sessile benthic organisms, and shelter for a large range of mobile organisms. They are often located in sub-tropical, temperate, and sub-polar latitudes. Ancient reefs buried within stratigraphic sections are of considerable interest to geologists because they provide paleo-environmental information about
434-494: The aggressive and successful campaign of German tourists to keep Borkum free from Jewish visitors, as celebrated in the antisemitic "Borkum- Lied ". In 1910, British officers Captain Bernard Frederick Trench and Lieutenant Vivian H. Brandon were imprisoned for espionage for photographing the military installations on the island. On 19 and 20 December 1934, Wernher von Braun launched "Max" and "Moritz" ,
465-482: The framework and bulk material comprising a coral reef, the organisms most responsible for reef growth against the constant assault from ocean waves are calcareous algae, especially, although not entirely, coralline algae . Oyster larvae prefer to settle on adult oysters and thereby develop layers building upwards. These eventually form a fairly massive hard stony calcium carbonate structure on which other reef organisms like sponges and seaweeds can grow, and provide
496-608: The framework builders. The corals which build reefs today, the Scleractinia , arose after the Permian–Triassic extinction event that wiped out the earlier rugose corals (as well as many other groups). They became increasingly important reef builders throughout the Mesozoic Era. They may have arisen from a rugose coral ancestor. Rugose corals built their skeletons of calcite and have a different symmetry from that of
527-488: The inhabitants became impoverished, and many left, with the island's population falling from 852 in 1776 to 406 by 1811. The first tourists arrived on the island in 1834, and the local economy improved as a tourist resort. In Mexico as I saw it , published by Thomas Nelson , Mrs Alec Tweedie , writing in 1911 about a trip of 1900 to Mexico , compares the brick roads of Monterrey with those of Borkum, "the one spot on earth from which Jews are banished". This had to do with
558-674: The location in Earth's history . In addition, reef structures within a sequence of sedimentary rocks provide a discontinuity which may serve as a trap or conduit for fossil fuels or mineralizing fluids to form petroleum or ore deposits . Corals, including some major extinct groups Rugosa and Tabulata , have been important reef builders through much of the Phanerozoic since the Ordovician Period. However, other organism groups, such as calcifying algae, especially members of
589-472: The potential to generate significant tidal power using tidal stream turbines . Tides are more predictable than wave power or wind power . The Pentland Firth (a strait) may be capable of generating 10 GW . Cook Strait in New Zealand may be capable of generating 5.6 GW even though the total energy available in the flow is 15 GW. Straits used for international navigation through
620-598: The red algae ( Rhodophyta ), and molluscs (especially the rudist bivalves during the Cretaceous Period) have created massive structures at various times. During the Cambrian Period, the conical or tubular skeletons of Archaeocyatha , an extinct group of uncertain affinities (possibly sponges), built reefs. Other groups, such as the Bryozoa, have been important interstitial organisms, living between
651-549: The result of an accident. These are sometimes designed to increase the physical complexity of featureless sand bottoms to attract a more diverse range of organisms . Reefs are often quite near to the surface, but not all definitions require this. Earth's largest coral reef system is the Great Barrier Reef in Australia, at a length of over 2,300 kilometres (1,400 miles). The word "reef" traces its origins back to
SECTION 20
#1732802346161682-421: The rugosan corals (which disappeared in the late Permian). An artificial reef is a human-created underwater structure, typically built to promote marine life in areas with a generally featureless bottom, to control erosion, block ship passage, block the use of trawling nets, or improve surfing . Many reefs are built using objects that were built for other purposes, for example by sinking oil rigs (through
713-471: The scleractinian corals, whose skeletons are aragonite . However, there are some unusual examples of well-preserved aragonitic rugose corals in the Late Permian . In addition, calcite has been reported in the initial post-larval calcification in a few scleractinian corals. Nevertheless, scleractinian corals (which arose in the middle Triassic) may have arisen from a non-calcifying ancestor independent of
744-857: The seafloor. Cyanobacterial mounds were most abundant before the evolution of shelly macroscopic organisms, but they still exist today. Stromatolites , for instance, are microbial mounds with a laminated internal structure. Whereas, bryozoans and crinoids , common contributors to marine sediments during the Mississippian period , produce a different kind of mound. Although bryozoans are small and crinoid skeletons disintegrate, bryozoan and crinoid meadows can persist over time and produce compositionally distinct bodies of sediment with depositional relief. The Proterozoic Belt Supergroup contains evidence of possible microbial mat and dome structures similar to stromatolite and chicken reef complexes. Rocky reefs are underwater outcrops of rock projecting above
775-442: The strait in both directions. In some straits there may be a dominant directional current through the strait. Most commonly, it is a narrowing channel that lies between two land masses . Some straits are not navigable, for example because they are either too narrow or too shallow, or because of an unnavigable reef or archipelago . Straits are also known to be loci for sediment accumulation. Usually, sand-size deposits occur on both
806-431: The surrounding sea floor . However, reefs are held up by a macroscopic skeletal framework, as what is seen on coral reefs. Corals and calcareous algae grow on top of one another, forming a three-dimensional framework that is modified in various ways by other organisms and inorganic processes. Conversely, mounds lack a macroscopic skeletal framework. Instead, they are built by microorganisms or by organisms that also lack
837-423: The territorial sea between one part of the high seas or an exclusive economic zone and another part of the high seas or an exclusive economic zone are subject to the legal regime of transit passage ( Strait of Gibraltar , Dover Strait , Strait of Hormuz ). The regime of innocent passage applies in straits used for international navigation (1) that connect a part of high seas or an exclusive economic zone with
868-591: The territorial sea of a coastal nation ( Straits of Tiran , Strait of Juan de Fuca , Strait of Baltiysk ) and (2) in straits formed by an island of a state bordering the strait and its mainland if there exists seaward of the island a route through the high seas or through an exclusive economic zone of similar convenience with respect to navigational and hydrographical characteristics ( Strait of Messina , Pentland Firth ). There may be no suspension of innocent passage through such straits. [REDACTED] Media related to Straits at Wikimedia Commons Reef A reef
899-574: The two opposite strait exits, forming subaqueous fans or deltas . The terms channel , pass , or passage can be synonymous and used interchangeably with strait , although each is sometimes differentiated with varying senses. In Scotland, firth or Kyle are also sometimes used as synonyms for strait. Many straits are economically important. Straits can be important shipping routes and wars have been fought for control of them. Numerous artificial channels, called canals , have been constructed to connect two oceans or seas over land, such as
930-509: The two prototypes of the A2 - rocket . In 1944, the island was the site of the massacre of 7 American POWs. After the war, these murders were prosecuted in the Borkum Island war crimes trial . The island is partially car-free . Off-season, driving by car is permitted everywhere, otherwise there are car-free zones . The only town on the island is also called Borkum. There is an airfield in
961-446: The year. This ensures varied weather with much sun and wind but also occasional rain and showers. Compared to the mainland, there is a climate with much milder winters and cooler summers without extremely cold or hot days. This is due to the buffering effect of the sea, which warms up slowly in spring and summer, but stores the warm temperatures longer in autumn. Mentioned as Burchana fabaria (island of beans) by both Strabo and Pliny