125-470: Dithmarschen ( German pronunciation: [ˈdɪtmaʁʃn̩] , Low Saxon : [ˈdɪtmaːʃn̩] ; archaic English: Ditmarsh ; Danish : Ditmarsken ; Medieval Latin : Tedmarsgo ) is a district in Schleswig-Holstein , Germany. It is bounded by (from the north and clockwise) the districts of Nordfriesland , Schleswig-Flensburg , Rendsburg-Eckernförde , and Steinburg , by
250-410: A bivalve is composed of calcium carbonate , and consists of two, usually similar, parts called valves . These valves are for feeding and for disposal of waste. These are joined together along one edge (the hinge line ) by a flexible ligament that, usually in conjunction with interlocking "teeth" on each of the valves, forms the hinge . This arrangement allows the shell to be opened and closed without
375-443: A credit. The relationship between Dithmarschen and Hamburg then turned icy, and Ditmarsians captured, according to the traditional wrecking custom , wrecked Hamburgian ships and their freight, if they foundered around the shores of Dithmarschen. (Earlier, Hamburg and Dithmarschen had agreed to replace this practice with a reward for rescuing ships, freight and crew.) The parties only reconciled in 1512. By 20 November 1499 Magnus hired
500-420: A different way, scraping detritus from the seabed, and this may be the original mode of feeding used by all bivalves before the gills became adapted for filter feeding. These primitive bivalves hold on to the bottom with a pair of tentacles at the edge of the mouth, each of which has a single palp , or flap. The tentacles are covered in mucus , which traps the food, and cilia, which transport the particles back to
625-528: A feature shared with two other major groups of marine invertebrates, the bryozoans and the phoronids . Some brachiopod shells are made of calcium phosphate but most are calcium carbonate in the form of the biomineral calcite , whereas bivalve shells are always composed entirely of calcium carbonate, often in the form of the biomineral aragonite . The Cambrian explosion took place around 540 to 520 million years ago (Mya). In this geologically brief period, most major animal phyla diverged including some of
750-460: A hinged shell in two parts. However, brachiopods evolved from a very different ancestral line, and the resemblance to bivalves only arose because they occupy similar ecological niches . The differences between the two groups are due to their separate ancestral origins. Different initial structures have been adapted to solve the same problems, a case of convergent evolution . In modern times, brachiopods are not as common as bivalves. Both groups have
875-420: A number of families that live in freshwater. Majority of the class are benthic filter feeders that bury themselves in sediment, where they are relatively safe from predation . Others lie on the sea floor or attach themselves to rocks or other hard surfaces. Some bivalves, such as scallops and file shells , can swim . Shipworms bore into wood, clay, or stone and live inside these substances. The shell of
1000-499: A pair of nephridia . Each of these consists of a long, looped, glandular tube, which opens into the pericardium , and a bladder to store urine. They also have pericardial glands either line the auricles of the heart or attach to the pericardium, and serve as extra filtration organs. Metabolic waste is voided from the bladders through a nephridiopore near the front of the upper part of the mantle cavity and excreted. The sexes are usually separate in bivalves but some hermaphroditism
1125-484: A relatively small dispersal potential before settling out. The common mussel ( Mytilus edulis ) produces 10 times as many eggs that hatch into larvae and soon need to feed to survive and grow. They can disperse more widely as they remain planktonic for a much longer time. Freshwater bivalves have different lifecycle. Sperm is drawn into a female's gills with the inhalant water and internal fertilization takes place. The eggs hatch into glochidia larvae that develop within
1250-644: A resting state, even when they are permanently submerged. In oysters, for example, their behaviour follows very strict circatidal and circadian rhythms according to the relative positions of the moon and sun. During neap tides, they exhibit much longer closing periods than during spring tides. Although many non-sessile bivalves use their muscular foot to move around, or to dig, members of the freshwater family Sphaeriidae are exceptional in that these small clams climb about quite nimbly on weeds using their long and flexible foot. The European fingernail clam ( Sphaerium corneum ), for example, climbs around on water weeds at
1375-424: A shadow falling over the animal. Bivalves have an open circulatory system that bathes the organs in blood ( hemolymph ). The heart has three chambers: two auricles receiving blood from the gills, and a single ventricle . The ventricle is muscular and pumps hemolymph into the aorta , and then to the rest of the body. Some bivalves have a single aorta, but most also have a second, usually smaller, aorta serving
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#17327833338731500-436: A shell consisting of two valves, but the organization of the shell is quite different in the two groups. In brachiopods, the two valves are positioned on the dorsal and ventral surfaces of the body, while in bivalves, the valves are on the left and right sides of the body, and are, in most cases, mirror images of one other. Brachiopods have a lophophore , a coiled, rigid cartilaginous internal apparatus adapted for filter feeding,
1625-447: A small airport prevents their erection, and the nature reserve at Speicherkoog, the whole coastline is lined by wind turbines. In 2003 they produced around KWH of energy, which is about half the energy demand of Dithmarschen. According to E.on -Hanse, the local energy company, in the same time it paid 59 million Euro for the energy, 3 to 5 million Euro were paid to farmers on whose land the turbines stand. The income through taxes for
1750-424: A steady pull. Paired pedal protractor and retractor muscles operate the animal's foot. The sedentary habits of the bivalves have meant that in general the nervous system is less complex than in most other molluscs. The animals have no brain ; the nervous system consists of a nerve network and a series of paired ganglia . In all but the most primitive bivalves, two cerebropleural ganglia are on either side of
1875-620: A wake of devastation in the countryside and especially in the looted monasteries. Finally, on Christmas Eve, arriving down the Weser in Lehe , the Black Guard tried to invade Wursten. However, the free peasants there repelled their attack near Weddewarden on 26 December. So the Guard turned northeastwards, looting Neuenwalde Nunnery underways, into Hadeln, repressing the joint forces of Rode and
2000-432: Is composed of two calcareous valves held together by a ligament. The valves are made of either calcite , as is the case in oysters, or both calcite and aragonite . Sometimes, the aragonite forms an inner, nacreous layer, as is the case in the order Pteriida . In other taxa , alternate layers of calcite and aragonite are laid down. The ligament and byssus, if calcified, are composed of aragonite. The outermost layer of
2125-557: Is known. The gonads either open into the nephridia or through a separate pore into a chamber over the gills. The ripe gonads of males and females release sperm and eggs into the water column . Spawning may take place continually or be triggered by environmental factors such as day length, water temperature, or the presence of sperm in the water. Some species are "dribble spawners", releasing gametes during protracted period that can extend for weeks. Others are mass spawners and release their gametes in batches or all at once. Fertilization
2250-715: Is more common in rural regions than in urban regions and more likely to be spoken by older Ditmarsians. The best known author of "high literature" in Low German was Klaus Groth from Heide. The best known Low German speaker in Germany today is probably Wilhelm Wieben , former anchorman of the popular German news Tagesschau , who now produces Low German audiobooks . Only two episodes of the popular crime television show Tatort carried subtitles for its German audience. One of these episodes centered its plot in Dithmarschen:
2375-502: Is ranked before Friedrichskoog (75,654) and Büsumer Deichhausen (33,811). Tourism has declined slightly over the last few years but not as much as tourism on the Schleswig-Holstein Baltic coast. Recent competition with the former Warsaw Pact states and their Baltic coasts has had less impact on Dithmarschen because their coastal formations are quite different. Entrance fees for beaches raise heated controversy in
2500-408: Is secreted by the mantle edge, and the valves themselves thicken as more material is secreted from the general mantle surface. Calcareous matter comes from both its diet and the surrounding seawater. Concentric rings on the exterior of a valve are commonly used to age bivalves. For some groups, a more precise method for determining the age of a shell is by cutting a cross section through it and examining
2625-472: Is the ventral or underside region. The anterior or front of the shell is where the byssus (when present) and foot are located, and the posterior of the shell is where the siphons are located. With the hinge uppermost and with the anterior edge of the animal towards the viewer's left, the valve facing the viewer is the left valve and the opposing valve the right. Many bivalves such as clams, which appear upright, are evolutionarily lying on their side. The shell
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#17327833338732750-432: Is usually external. Typically, a short stage lasts a few hours or days before the eggs hatch into trochophore larvae. These later develop into veliger larvae which settle on the seabed and undergo metamorphosis into adults. In some species, such as those in the genus Lasaea , females draw water containing sperm in through their inhalant siphons and fertilization takes place inside the female. These species then brood
2875-612: The Early Silurian , the gills were becoming adapted for filter feeding, and during the Devonian and Carboniferous periods, siphons first appeared, which, with the newly developed muscular foot, allowed the animals to bury themselves deep in the sediment. By the middle of the Paleozoic , around 400 Mya, the brachiopods were among the most abundant filter feeders in the ocean, and over 12,000 fossil species are recognized. By
3000-530: The Hanseatic Diets (Hansetage). In 1554 the Hanseatic Diet confirmed, that free Ditmarsian peasants doing business cannot be considered equal to merchants being burghers of free or autonomous cities, but are, nevertheless, accepted as enjoying all Hanseatic advantages. Thus Ditmarsian merchants, along with those from Teutonic Prussia , were the only beneficiaries of a quasi membership within
3125-571: The Kalmar Union . These forces then invaded Dithmarschen in order to subject the free Ditmarsians. The Ditmarsians took a vow to donate a monastery in honour of the then national patron saint Mary of Nazareth if they could repel the invasion. On 17 February 1500, in the Battle of Hemmingstedt , the outnumbered Ditmarsians, led by Wulf Isebrand , defeated the invading armies and thus destroyed King John's dream of subjecting Dithmarschen. In 1513
3250-702: The Knicks [ de ] , tree rows with strong undergrowth to protect agricultural land from the wind. In Dithmarschen lay several bogs. A special position is taken with the "Weißes Moor" (White bog), the only bog still existing in quite natural shape in the Schleswig-Holstein marsh land. Part of the Schleswig-Holstein Wadden Sea National Park is in Dithmarschen. It is the most important habitat in
3375-668: The Lamellibranchiata and Pelecypoda , is a class of aquatic molluscs (marine and freshwater) that have laterally compressed soft bodies enclosed by a calcified exoskeleton consisting of a hinged pair of half- shells known as valves . As a group, bivalves have no head and lack some typical molluscan organs such as the radula and the odontophore . Their gills have evolved into ctenidia , specialised organs for feeding and breathing. Common bivalves include clams , oysters , cockles , mussels , scallops , and numerous other families that live in saltwater, as well as
3500-636: The Land of Wursten , a de facto autonomous region in a North Sea marsh at the Weser estuary, which was under the loose overlordship of the Prince-Archbishopric of Bremen. This foreshadowed a series of feudal attempts to subdue regions of free peasants, an alarming signal for the Ditmarsians and the free peasants in other marshes in the area. In April 1499 Count John XIV of Oldenburg invaded
3625-675: The Otterndorf Strife (Otterndorfer Streit). The landsknecht created rumours that it had instead been a Ditmarsian who had slain von der Lieth, and fled after. Hamburg's landsknechts then attacked the uninvolved Ditmarsians and slew 76 men in their military camp near Otterndorf . Consequently, Dithmarschen cancelled its alliance with Rode, Bremen and Hamburg, and the Ditmarsians returned home. Hamburg aimed at reestablishing its rule in Hadeln, as it had wielded between 1407 and 1481 when Saxe-Lauenburg had given Hadeln to Hamburg as security for
3750-726: The Permian–Triassic extinction event 250 Mya, bivalves were undergoing a huge radiation of diversity. The bivalves were hard hit by this event, but re-established themselves and thrived during the Triassic period that followed. In contrast, the brachiopods lost 95% of their species diversity . The ability of some bivalves to burrow and thus avoid predators may have been a major factor in their success. Other new adaptations within various families allowed species to occupy previously unused evolutionary niches. These included increasing relative buoyancy in soft sediments by developing spines on
3875-629: The Province of Schleswig-Holstein . The Middle Ages in Dithmarschen are held to have continued into the 19th century, when the Kiel Canal was completed, fens began to be drained, and agricultural reforms took place. Within the Bundesland Schleswig-Holstein, the area remained divided into the districts of Norderdithmarschen (Northern Ditmarsh) and Süderdithmarschen (Southern Ditmarsh) before they were united in 1970 as
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4000-1005: The Sparkasse Westholstein (600), the Royal Dutch Shell refinery in Hemmingstedt (570), the Sasol chemistry works in Brunsbüttel (570), the printing company Evers in Meldorf (560), and the Beyschlag manufacturing plant in Heide. The Bundeswehr has a school for non-commissioned officers in Heide. In recent years the number of people who live in Dithmarschen but work in Hamburg and its surroundings has steadily risen. In 2002 9,200 people drove to work outside
4125-587: The Veneridae , with more than 680 species and the Tellinidae and Lucinidae , each with over 500 species. The freshwater bivalves include seven families, the largest of which are the Unionidae , with about 700 species. The taxonomic term Bivalvia was first used by Linnaeus in the 10th edition of his Systema Naturae in 1758 to refer to animals having shells composed of two valves . More recently,
4250-526: The geestland , is 78 metres (256 ft) meters above sea level and the lowest point, near Burg, is 0.5 metres (1 ft 8 in) below sea level. Dithmarschen's landscape owes its character to the North Sea. From west to east Dithmarschen consists of the Wadden Sea , marsh , bog , and the geestland . The North Sea had a higher sea level 6,500 years ago than today and the coastline then ran along
4375-597: The intertidal and sublittoral zones of the oceans. A sandy sea beach may superficially appear to be devoid of life, but often a very large number of bivalves and other invertebrates are living beneath the surface of the sand. On a large beach in South Wales , careful sampling produced an estimate of 1.44 million cockles ( Cerastoderma edule ) per acre of beach. Bivalves inhabit the tropics, as well as temperate and boreal waters. A number of species can survive and even flourish in extreme conditions. They are abundant in
4500-517: The oesophagus . The cerebral ganglia control the sensory organs, while the pleural ganglia supply nerves to the mantle cavity. The pedal ganglia, which control the foot, are at its base, and the visceral ganglia, which can be quite large in swimming bivalves, are under the posterior adductor muscle. These ganglia are both connected to the cerebropleural ganglia by nerve fibres . Bivalves with long siphons may also have siphonal ganglia to control them. The sensory organs of bivalves are largely located on
4625-400: The " crystalline style " projected into the stomach from an associated sac. Cilia in the sac cause the style to rotate, winding in a stream of food-containing mucus from the mouth, and churning the stomach contents. This constant motion propels food particles into a sorting region at the rear of the stomach, which distributes smaller particles into the digestive glands, and heavier particles into
4750-408: The 15th century the Ditmarsians confederated in a peasant republic . Though several times neighbouring princely rulers, accompanied by their knights and mercenaries , attempted to subjugate the independent peasants to feudalism, they were unsuccessful. In 1319 Gerhard III was repelled in the Battle of Wöhrden [ de ] . After Eric IV, Duke of Saxe-Lauenburg had raided Dithmarschen,
4875-483: The 1930s to make them habitable to humans, they are now part of the national park, forbidden to humans. Many birds preferring wet grasslands live in the Eider-Treene Valley . In medieval times the marshland villages of Dithmarschen enjoyed remarkable autonomy. Neighbouring princes often tried to bring Dithmarschen under their control. After 1180 Prince-Archbishop Siegfried ceded Dithmarschen, which
5000-458: The Arctic, about 140 species being known from that zone. The Antarctic scallop, Adamussium colbecki , lives under the sea ice at the other end of the globe, where the subzero temperatures mean that growth rates are very slow. The giant mussel, Bathymodiolus thermophilus , and the giant white clam, Calyptogena magnifica , both live clustered around hydrothermal vents at abyssal depths in
5125-466: The Ditmarsians after subjugation. In 1187 and 1188 Hartwig and his ally Maurice I, Count of Oldenburg , heading their troops, invaded Dithmarschen. The free peasants promised to pay him dues, only to ridicule and renounce Hartwig, once he and his soldiers had left. The Ditmarsians gained support from Valdemar , steward of the Duchy of Schleswig and Bishop of Schleswig . Hartwig, owing dues to Adolf III and
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5250-486: The Ditmarsians blamed his son-in-law, Albert II, Count of Holstein-Rendsburg , for complicity, who then used this as a pretext for his own unsuccessful conquest attempt in 1403, dying during the campaign from inflicted injuries. In 1468 Dithmarschen allied with Lübeck to protect their common interest as to commerce and containing the spreading feudalism in the region. Based on the Hanseatic obligations and privileges from
5375-685: The Ditmarsians founded a Franciscan Friary in Lunden fulfilling their vow. However, the Hamburg concathedral chapter , holding the ecclesiastical jurisdiction, demanded its say in appointing the prebendaries . After years of dispute, the Council of the 48, the elected governing body of the farmers' republic of Ditmarsh, decided to found a Gallicanist kind of independent Catholic Church of Dithmarschen in August 1523, denying Hamburg's capitular jurisdiction in all of Dithmarschen. The chapter could not regain
5500-571: The Elbe, easily conquered the Land of Hadeln, and defeated Magnus. While the cities desired a peaceful front yard without another's powerful influence, the Ditmarsians instead favoured the favour of autonomy of the free peasants. Hamburg and the Ditmarsians fell out with each other. On 16 September 1499, a landsknecht hired by Hamburg slew Cordt von der Lieth, a member of the Bremian ministerialis , causing
5625-461: The Elder of Brunswick and Lunenburg , Prince of Wolfenbüttel , on 24 November 1498, to conquer Wursten. Henry IV obliged to send 3,000 landsknechts , who should gain their payment by ravaging and plundering the free peasants of Wursten, once successfully subjugated. Rode then waged feud against John V of Saxe-Lauenburg on 9 September 1499. The allied forces, with the Ditmarsians invading by crossing
5750-593: The Geest existed before their churches were built and there was no special need to protect these churches from flooding. The most important church of Dithmarschen was the so-called Sankt-Johannis-Kirche (St. John's the Baptist Church) in Meldorf, due to its size also called Meldorf Cathedral. Between the 9th and 11th century it was the only church in Dithmarschen and one of the few north of the Elbe River. In
5875-541: The Guard and guaranteed for its safe conduct first southeastwards via Lunenburg-Cellean Winsen upon Luhe and Hoopte, crossing the Elbe by Zollenspieker Ferry to the Hamburg-Lübeckian bi-urban condominium (Beiderstädtischer Besitz) of Bergedorf and Vierlande . From there the Black Guard headed northwestwards again through Holstein in order to join more of King John's forces recruited in Holstein and by
6000-559: The Hanse, although lacking the background of citizenship in an autonomous or free city . It was not until 1559 and the Last Feud between the King of Denmark and the Ditmarsians that the free peasants were forced to give up their political and religious autonomy by the successful invasion commanded by Count Johan Rantzau from Steinburg , one of the best strategists of the time . Since then
6125-520: The Low German in the dialogue was thought to be too difficult for a generic German audience to follow. The Dithmarschen landscape was long dominated by churches. Palaces were never built in the farmers' republic. The few castles that were constructed played only minor roles and have long since been reduced to groundworks. In contrast, churches were symbols of not only spiritual but also worldly power. The medieval republic organised itself into Parishes ("Kirchspiele") centered on churches. A Dithmarschen church
6250-632: The Middle Ages the church was the venue of the representatives of the political parishes of Dithmarschen. The place around this church was the most important meeting place in Dithmarschen and Meldorf itself was the only settlement to develop a distinct urban structure. Even after the political center moved to Heide, the St. John's in Meldorf remained the most important religious site in Dithmarschen. The Reformation in Dithmarschen began there in 1524 with Dithmarschen converting to Lutheranism . Today's church
6375-464: The Pacific Ocean. They have chemosymbiotic bacteria in their gills that oxidise hydrogen sulphide , and the molluscs absorb nutrients synthesized by these bacteria. Some species are found in the hadal zone , like Vesicomya sergeevi, which occurs at depths of 7600–9530 meters. The saddle oyster, Enigmonia aenigmatica , is a marine species that could be considered amphibious . It lives above
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#17327833338736500-502: The Romans, and mariculture has more recently become an important source of bivalves for food. Modern knowledge of molluscan reproductive cycles has led to the development of hatcheries and new culture techniques. A better understanding of the potential hazards of eating raw or undercooked shellfish has led to improved storage and processing. Pearl oysters (the common name of two very different families in salt water and fresh water) are
6625-751: The Wadden Sea and therefore are for around three weeks unable to fly. The majority of common shelducks in North Western Europe travel to the area at this time. Big salt marshes are at the Friedrichskoog coast and in the Neufeld Bay. Three sand banks, Trischen , Tertius and Blauort are in the sea. They are some of only a few still natural habitats at the German coast and of importance to sea birds and seals. After futile attempts in
6750-411: The Weser and North Sea marshes of Stadland and Butjadingen , both of which the Prince-Archbishopric of Bremen claimed overlordship over, in order to subject their free peasants. Bremen's prince-archbishop Johann Rode tried to form a military alliance to repel these invasions, and prevent further ones, first rallying the cities of Bremen , Hamburg and Stade , as they considered the areas downstream of
6875-472: The air, can gape the shell slightly and gas exchange can take place. Oysters, including the Pacific oyster ( Magallana gigas ), are recognized as having varying metabolic responses to environmental stress, with changes in respiration rate being frequently observed. Most bivalves are filter feeders , using their gills to capture particulate food such as phytoplankton from the water. Protobranchs feed in
7000-615: The approximately two million tourists each year come from Germany. The unemployment rate was 11.6% in September 2004. After the Hartz concept was implemented and new statistical methods were adopted, the unemployment rate rose to 17.4% in January 2005. The unemployment rate was far above the average for Schleswig-Holstein (12.7%) and the rest of Germany. The most important employers in the district are Bayer in Brunsbüttel (1,000 employees),
7125-520: The baroque building from the remains of older churches after Wesselburen burned down in 1736. Its onion dome is highly unusual for Northern Germany. Also notable are the 12th-century church in Tellingstedt and the churches in Hemme and Büsum , which display the traditional coat of arms of the "Geschlechter" inside. In 1993 Schleswig-Holstein's latest Fachhochschule (comparable to a Polytechnics )
7250-540: The cities – lacking support by Bremian knights and the Ditmarsians –, recapturing it for Magnus in early 1500. Rode then converted Henry IV the Elder to his column, with Henry the Elder and his troops then hunting the Black Guard. Magnus, unable to pay the mercenaries so that they turned even the more oppressive for the local population, was like the Sorcerer's Apprentice , who could not get rid of "the spirits that he called". By mid-January 1500 King John of Denmark hired
7375-572: The class was known as Pelecypoda, meaning " axe -foot" (based on the shape of the foot of the animal when extended). The name "bivalve" is derived from the Latin bis , meaning 'two', and valvae , meaning 'leaves of a door'. ("Leaf" is an older word for the main, movable part of a door. We normally consider this the door itself.) Paired shells have evolved independently several times among animals that are not bivalves; other animals with paired valves include certain gastropods (small sea snails in
7500-481: The coast produces 2 million tons of petroleum, around 54% of German production. The refinery in Hemmingstedt processes around 4 million tons of oil each year, partly from Mittelplate and partly from oil delivered through the Brunsbüttel port. Another oil field between Heide and Hemmingstedt was active until 1991. The nuclear power plant in Brunsbuttel is one of the oldest in Germany. It delivers cheap energy for
7625-406: The coat of arms of Dithmarschen has shown a warrior on horseback, representing a knight of Rantzau. This knight has later been identified with Saint George , then considered to be the patron of Dithmarschen. The conquerors – King Frederick II , Duke Adolf , and Duke John II the Elder – divided Dithmarschen into two parts: the south became a part of Holstein in personal union with Denmark while
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#17327833338737750-432: The district is around 4 million Euro each year. Because commercial wind farming in Germany began in Dithmarschen, many wind turbines are relative old and produce only a small amount of electricity. For people interested in wind turbines this makes an interesting contrast, though, since it is possible to see many working varieties of wind turbines standing close to each other. The offshore oil field Mittelplate close to
7875-529: The district of Dithmarschen. The people of Dithmarschen have displayed great pride in their history. In recent decades many traditions have been revitalized and new events in a traditional fashion have been created. High German is by now the dominant language but Low German in its Holsteinisch version still has a place in informal conversation. Until the 1960s Low German was the prevailing language of everyday communication. Most Ditmarsians born before 1960 still consider Low German their mother tongue. Low German
8000-544: The district there are six Gymnasia , three Fachgymnasia , two vocational schools, and 44 schools for primary education. The Dithmarschen economy consists mainly of tourism, agriculture, and energy. Tourism is concentrated in the north in Büsum and in the south in Friedrichskoog . Most tourists come as families to enjoy the North Sea beaches. A significant number of tourists also come for bicycle trekking. Almost all of
8125-640: The district, including 1,700 who commuted to Hamburg. Commercial wind farming in Germany began in Dithmarschen. Germany's first wind park was opened 1987 in Kaiser-Wilhelm-Koog , the experimental GROWIAN ("Große Windkraftanlage" – big wind turbine) stood there from 1983 to 1987. As of 2008 the tallest wind turbine in the world is the experimental Enercon E-126 near Emden . In Dithmarschen stand around 800 wind turbines , almost all of them in marshland. That means that 5% of all German wind turbines stand on 0.15% of its area. Except for Büsum, where
8250-693: The district. Büsum (around 1,000,000 beach visits each year) and Friedrichskoog (300,000) impose a fee. However, most smaller villages nearby do not. Northern Low Saxon Too Many Requests If you report this error to the Wikimedia System Administrators, please include the details below. Request from 172.68.168.226 via cp1108 cp1108, Varnish XID 227528027 Upstream caches: cp1108 int Error: 429, Too Many Requests at Thu, 28 Nov 2024 08:42:14 GMT Bivalve And see text Bivalvia ( / b aɪ ˈ v æ l v i ə / ) or bivalves , in previous centuries referred to as
8375-720: The district. Many molluscs can be found here, including bivalves and gastropods , worms and crustaceans , which provide food to larger animals. Fish use the Wadden Sea as a "Kindergarten" where they can raise their offspring in a protected environment. Although many species of birds settle permanently in the Wadden Sea, many others use it as a winter habitat or as a resting place. Typical birds in Dithmarschen are dunlin , red knot , bar-tailed godwit , northern lapwings , ringed plover , Eurasian oystercatcher , many species of duck and gull , sandwich tern , pied avocet , brent goose and barnacle goose . 200,000 common shelducks alone come in August, The shelducks lose their feathers in
8500-436: The edges of lakes and ponds; this enables the clam to find the best position for filter feeding. The thick shell and rounded shape of bivalves make them awkward for potential predators to tackle. Nevertheless, a number of different creatures include them in their diet. Many species of demersal fish feed on them including the common carp ( Cyprinus carpio ), which is being used in the upper Mississippi River to try to control
8625-402: The family Juliidae ), members of the phylum Brachiopoda and the minute crustaceans known as ostracods and conchostracans . Bivalves have bilaterally symmetrical and laterally flattened bodies, with a blade-shaped foot, vestigial head and no radula . At the dorsal or back region of the shell is the hinge point or line, which contain the umbo and beak and the lower, curved margin
8750-421: The female's shell. Later they are released and attach themselves parasitically to the gills or fins of a fish host. After several weeks they drop off their host, undergo metamorphosis and develop into adults on the substrate . Some of the species in the freshwater mussel family, Unionidae , commonly known as pocketbook mussels, have evolved an unusual reproductive strategy. The female's mantle protrudes from
8875-434: The first creatures with mineralized skeletons. Brachiopods and bivalves made their appearance at this time, and left their fossilized remains behind in the rocks. Possible early bivalves include Pojetaia and Fordilla ; these probably lie in the stem rather than crown group. Watsonella and Anabarella are perceived to be (earlier) close relatives of these taxa. Only five genera of supposed Cambrian "bivalves" exist,
9000-434: The fish's gills, where they attach and trigger a tissue response that forms a small cyst around each larva. The larvae then feed by breaking down and digesting the tissue of the fish within the cysts. After a few weeks they release themselves from the cysts and fall to the stream bed as juvenile molluscs. Brachiopods are shelled marine organisms that superficially resemble bivalves in that they are of similar size and have
9125-425: The geestland. About 4,500 years ago, geestland structures were connected by sand and gravel depositions that formed spits . Bogs, lakes, and swamps emerged as the area behind the spits no longer flooded. After the first plants ( glasswort ) took root, the land transformed first to salt marshes and finally to marshes. These marshes rank among the most fertile of Germany's soils. Vegetable farming in Dithmarschen produces
9250-467: The gills are also much longer than those in more primitive bivalves, and are folded over to create a groove through which food can be transported. The structure of the gills varies considerably, and can serve as a useful means for classifying bivalves into groups. A few bivalves, such as the granular poromya ( Poromya granulata ), are carnivorous , eating much larger prey than the tiny microalgae consumed by other bivalves. Muscles draw water in through
9375-503: The heath"); later, the Council of the 48—representatives of the most important families and the central decision body of Dithmarschen—met at St. Jürgen. The core of the long, single-nave church is still the 15th-century building. Its outer appearance is dominated by a late-renaissance three-story tower added by Johann Georg Schott in 1724. St. Bartholomäus in Wesselburen was also built in 1737/1738 by Johann Georg Schott. He constructed
9500-595: The high tide mark in the tropical Indo-Pacific on the underside of mangrove leaves, on mangrove branches, and on sea walls in the splash zone . Some freshwater bivalves have very restricted ranges. For example, the Ouachita creekshell mussel, Villosa arkansasensis , is known only from the streams of the Ouachita Mountains in Arkansas and Oklahoma, and like several other freshwater mussel species from
9625-460: The highest point of the Terpen in the center of villages such as Wesselburen , Marne , and Wöhrden . Village streets run toward the central church, giving these villages a distinct medieval character. It is likely that older houses were removed to make room for these churches. In the Geest, the village church stands on the medieval rim of the village or with other houses within it; the settlements of
9750-458: The highest yields in Schleswig-Holstein. Since about the 8th century, the people of Dithmarschen have been living on warfts for protection from the sea. In the 12th century, they began building dikes to protect their pastures and fields. Since about the 15th century, they have been reclaiming land from the sea. While the Geest has some woods, trees are found in marshlands only in form of wind protection around houses or villages. Traditional are
9875-434: The hind parts of the animal. The hemolymph usually lacks any respiratory pigment. In the carnivorous genus Poromya , the hemolymph has red amoebocytes containing a haemoglobin pigment. The paired gills are located posteriorly and consist of hollow tube-like filaments with thin walls for gas exchange . The respiratory demands of bivalves are low, due to their relative inactivity. Some freshwater species, when exposed to
10000-539: The important aluminium industry in Schleswig-Holstein. It is supposed to close down in 2009. The main tourist attractions in Dithmarschen are the North Sea and the Wadden Sea National Park . The district owns about 10 kilometers of green beaches; Büsum also provides an artificial sandy beach. In 2003, 205,382 tourists spent 1,173,205 nights in Dithmarschen, most of them in Büsum (756,630 nights), which
10125-399: The incremental growth bands. The shipworms , in the family Teredinidae have greatly elongated bodies, but their shell valves are much reduced and restricted to the anterior end of the body, where they function as scraping organs that permit the animal to dig tunnels through wood. The main muscular system in bivalves is the posterior and anterior adductor muscles. These muscles connect
10250-526: The inhalant siphon is surrounded by vibration-sensitive tentacles for detecting prey. Many bivalves have no eyes, but a few members of the Arcoidea, Limopsoidea, Mytiloidea, Anomioidea, Ostreoidea, and Limoidea have simple eyes on the margin of the mantle. These consist of a pit of photosensory cells and a lens . Scallops have more complex eyes with a lens, a two-layered retina , and a concave mirror. All bivalves have light-sensitive cells that can detect
10375-421: The inhalant siphon which is modified into a cowl-shaped organ, sucking in prey. The siphon can be retracted quickly and inverted, bringing the prey within reach of the mouth. The gut is modified so that large food particles can be digested. The unusual genus, Entovalva , is endosymbiotic , being found only in the oesophagus of sea cucumbers . It has mantle folds that completely surround its small valves. When
10500-443: The intestine. Waste material is consolidated in the rectum and voided as pellets into the exhalent water stream through an anal pore. Feeding and digestion are synchronized with diurnal and tidal cycles. Carnivorous bivalves generally have reduced crystalline styles and the stomach has thick, muscular walls, extensive cuticular linings and diminished sorting areas and gastric chamber sections. The excretory organs of bivalves are
10625-494: The invasive zebra mussel ( Dreissena polymorpha ). Birds such as the Eurasian oystercatcher ( Haematopus ostralegus ) have specially adapted beaks which can pry open their shells. The herring gull ( Larus argentatus ) sometimes drops heavy shells onto rocks in order to crack them open. Sea otters feed on a variety of bivalve species and have been observed to use stones balanced on their chests as anvils on which to crack open
10750-657: The jurisdiction, including its share in ecclesiastical fees and fines levied in Dithmarschen. After violently repelling the first preaching of proponents of the Reformation , slaying Henry of Zutphen in December 1524, Lutheranism nevertheless started to win over Ditmarsians. In 1533 the Council of the 48 turned the Ditmarsian Catholic Church into a Lutheran state church . After the victory of Hemmingstedt Dithmarschen regularly sent its delegates to
10875-485: The largest living bivalve is the giant clam Tridacna gigas , which can grow to a length of 1,200 mm (47 in) and a weight of more than 200 kg (441 lb). The largest known extinct bivalve is a species of Platyceramus whose fossils measure up to 3,000 mm (118 in) in length. In his 2010 treatise, Compendium of Bivalves , Markus Huber gives the total number of living bivalve species as about 9,200 combined in 106 families. Huber states that
11000-418: The mantle lobes secrete the valves, and the mantle crest secretes the whole hinge mechanism consisting of ligament , byssus threads (where present), and teeth . The posterior mantle edge may have two elongated extensions known as siphons , through one of which water is inhaled, and the other expelled. The siphons retract into a cavity, known as the pallial sinus . The shell grows larger when more material
11125-452: The mantle though the valves. In sedentary or recumbent bivalves that lie on one valve, such as the oysters and scallops, the anterior adductor muscle has been lost and the posterior muscle is positioned centrally. In species that can swim by flapping their valves, a single, central adductor muscle occurs. These muscles are composed of two types of muscle fibres, striated muscle bundles for fast actions and smooth muscle bundles for maintaining
11250-626: The most common source of natural pearls . The shells of bivalves are used in craftwork, and the manufacture of jewellery and buttons. Bivalves have also been used in the biocontrol of pollution. Bivalves appear in the fossil record first in the early Cambrian more than 500 million years ago. The total number of known living species is about 9,200. These species are placed within 1,260 genera and 106 families. Marine bivalves (including brackish water and estuarine species) represent about 8,000 species, combined in four subclasses and 99 families with 1,100 genera. The largest recent marine families are
11375-799: The north came into the possession of the other Duke of Holstein. From 1773 all of Holstein was united in personal union with Denmark and remained so until 1864, when, following the Second Schleswig War , the Duchies of Holstein and of Schleswig became an occupied territory of the German Confederation . Two years later, following the Austro-Prussian War , Dithmarschen became part of the Kingdom of Prussia , which annexed Holstein and Schleswig making them subsequently
11500-472: The north. Today it forms a kind of artificial island , surrounded by the Eider river in the north and the Kiel Canal in both the east and southeast. It is a rather flat countryside that was once full of fens and swamps. To the north it borders on Nordfriesland and Schleswig-Flensburg , to the east on Rendsburg-Eckernförde , and in the southeast on Steinburg . Its landward boundaries have remained basically
11625-422: The number of 20,000 living species, often encountered in literature, could not be verified and presents the following table to illustrate the known diversity: The bivalves are a highly successful class of invertebrates found in aquatic habitats throughout the world. Most are infaunal and live buried in sediment on the seabed, or in the sediment in freshwater habitats. A large number of bivalve species are found in
11750-507: The others being Tuarangia , Camya and Arhouriella and potentially Buluniella . Bivalve fossils can be formed when the sediment in which the shells are buried hardens into rock. Often, the impression made by the valves remains as the fossil rather than the valves. During the Early Ordovician , a great increase in the diversity of bivalve species occurred, and the dysodont, heterodont, and taxodont dentitions evolved. By
11875-407: The pact signed with Lübeck, Ditmarsians had established trade with Livonia and neighbouring Baltic destinations in the 15th century. Both parties renewed their alliance several times and it thus lasted until Dithmarschen's final defeat and Dano-Holsatian annexation in 1559. In 1484 Magnus of Saxe-Lauenburg , then vicegerent of the Land of Hadeln, failed to subjugate the free Frisian peasants in
12000-400: The palps. These then sort the particles, rejecting those that are unsuitable or too large to digest, and conveying others to the mouth. In more advanced bivalves, water is drawn into the shell from the posterior ventral surface of the animal, passes upwards through the gills, and doubles back to be expelled just above the intake. There may be two elongated, retractable siphons reaching up to
12125-523: The period is before the larva first feeds, the larger the egg and yolk need to be. The reproductive cost of producing these energy-rich eggs is high and they are usually smaller in number. For example, the Baltic tellin ( Macoma balthica ) produces few, high-energy eggs. The larvae hatching out of these rely on the energy reserves and do not feed. After about four days, they become D-stage larvae, when they first develop hinged, D-shaped valves. These larvae have
12250-409: The posterior mantle margins. The organs are usually mechanoreceptors or chemoreceptors , in some cases located on short tentacles . The osphradium is a patch of sensory cells located below the posterior adductor muscle that may serve to taste the water or measure its turbidity . Statocysts within the organism help the bivalve to sense and correct its orientation. In the order Anomalodesmata ,
12375-527: The prominence of modern bivalves over brachiopods seems due to chance disparities in their response to extinction events . The adult maximum size of living species of bivalve ranges from 0.52 mm (0.02 in) in Condylonucula maya , a nut clam, to a length of 1,532 millimetres (60.3 in) in Kuphus polythalamia , an elongated, burrowing shipworm. However, the species generally regarded as
12500-454: The rivers Elbe and Weser their own front yard: essential for their free maritime trade connections. Rode won the Ditmarsians too, for a defensive alliance to protect Wursten, concluded on 1 May 1499. On 1 August the alliance, now also including Buxtehude , committed themselves to supply 1,300 warriors and equipment to defend Wursten and/or invade Hadeln. Conversely, John V and his son Magnus of Saxe-Lauenburg had already allied with Henry IV
12625-422: The same since the times of Charlemagne . Land reclamation , however, has almost doubled the size of Dithmarschen as land has been wrested from the sea. The main roads and rail lines in Schleswig-Holstein follow a north–south direction, making Hamburg its most accessible city. The district has a maximum north–south length of 54 kilometers and an east–west length of 41 kilometers. The highest point, near Schrum in
12750-496: The sea cucumber sucks in sediment, the bivalve allows the water to pass over its gills and extracts fine organic particles. To prevent itself from being swept away, it attaches itself with byssal threads to the host 's throat. The sea cucumber is unharmed. The digestive tract of typical bivalves consists of an oesophagus , stomach , and intestine . Protobranch stomachs have a mere sac attached to them while filter-feeding bivalves have elongated rod of solidified mucus referred to as
12875-419: The seabed, one each for the inhalant and exhalant streams of water. The gills of filter-feeding bivalves are known as ctenidia and have become highly modified to increase their ability to capture food. For example, the cilia on the gills, which originally served to remove unwanted sediment, have become adapted to capture food particles, and transport them in a steady stream of mucus to the mouth. The filaments of
13000-469: The sediment remains damp even when the tide is out. When buried in the sediment, burrowing bivalves are protected from the pounding of waves, desiccation, and overheating during low tide, and variations in salinity caused by rainwater. They are also out of the reach of many predators. Their general strategy is to extend their siphons to the surface for feeding and respiration during high tide, but to descend to greater depths or keep their shell tightly shut when
13125-435: The shell and develops into an imitation small fish, complete with fish-like markings and false eyes. This decoy moves in the current and attracts the attention of real fish. Some fish see the decoy as prey, while others see a conspecific . They approach for a closer look and the mussel releases huge numbers of larvae from its gills, dousing the inquisitive fish with its tiny, parasitic young. These glochidia larvae are drawn into
13250-468: The shell is the periostracum , a thin layer composed of horny conchiolin . The periostracum is secreted by the outer mantle and is easily abraded. The outer surface of the valves is often sculpted, with clams often having concentric striations, scallops having radial ribs and oysters a latticework of irregular markings. In all molluscs, the mantle forms a thin membrane that covers the animal's body and extends out from it in flaps or lobes. In bivalves,
13375-571: The shell, gaining the ability to swim, and in a few cases, adopting predatory habits. For a long time, bivalves were thought to be better adapted to aquatic life than brachiopods were, outcompeting and relegating them to minor niches in later ages. These two taxa appeared in textbooks as an example of replacement by competition. Evidence given for this included the fact that bivalves needed less food to subsist because of their energetically efficient ligament-muscle system for opening and closing valves. All this has been broadly disproven, though; rather,
13500-420: The shells and open them more easily when they could tackle them from different angles. Octopuses either pull bivalves apart by force, or they bore a hole into the shell and insert a digestive fluid before sucking out the liquified contents. Certain carnivorous gastropod snails such as whelks ( Buccinidae ) and murex snails ( Muricidae ) feed on bivalves by boring into their shells. A dog whelk ( Nucella ) drills
13625-400: The shells with their pincers and starfish use their water vascular system to force the valves apart and then insert part of their stomach between the valves to digest the bivalve's body. It has been found experimentally that both crabs and starfish preferred molluscs that are attached by byssus threads to ones that are cemented to the substrate. This was probably because they could manipulate
13750-740: The shells. The Pacific walrus ( Odobenus rosmarus divergens ) is one of the main predators feeding on bivalves in Arctic waters. Shellfish have formed part of the human diet since prehistoric times, a fact evidenced by the remains of mollusc shells found in ancient middens. Examinations of these deposits in Peru has provided a means of dating long past El Niño events because of the disruption these caused to bivalve shell growth. Further changes in shell development due to environmental stress has also been suggested to cause increased mortality in oysters due to reduced shell strength. Invertebrate predators include crustaceans, starfish and octopuses. Crustaceans crack
13875-620: The so-called Black Guard [ de ] of 6,000 ruthless and violent mostly Dutch and East Frisian mercenaries, commanded by Thomas Slentz , prior operating in the County of Oldenburg . The Black Guard invaded the Prince-Archbishopric of Bremen, passing through and ravaging areas in the Prince-Bishopric of Verden and the Brunswick-Lunenburgian Principality of Lunenburg-Celle , leaving behind
14000-490: The soldiers' pay to Maurice I, was trapped and could not afford to wage a second war. In 1192 the Bremian Chapter elected Valdemar as its new Prince-Archbishop. Valdemar welcomed his election, hoping his new position could be helpful in his dispute with Duke Valdemar of Schleswig and his elder brother Canute VI of Denmark . Before entering the Prince-Archbishopric of Bremen he won the support of Dithmarschen. In
14125-584: The southeastern US, it is in danger of extinction. In contrast, a few species of freshwater bivalves, including the golden mussel ( Limnoperna fortunei ), are dramatically increasing their ranges. The golden mussel has spread from Southeast Asia to Argentina, where it has become an invasive species . Another well-travelled freshwater bivalve, the zebra mussel ( Dreissena polymorpha ) originated in southeastern Russia, and has been accidentally introduced to inland waterways in North America and Europe, where
14250-416: The species damages water installations and disrupts local ecosystems . Most bivalves adopt a sedentary or even sessile lifestyle, often spending their whole lives in the area in which they first settled as juveniles. The majority of bivalves are infaunal, living under the seabed, buried in soft substrates such as sand, silt, mud, gravel, or coral fragments. Many of these live in the intertidal zone where
14375-690: The state of Lower Saxony (district of Stade , from which it is separated by the Elbe river), and by the North Sea . From the 13th century up to 1559 Dithmarschen was an independent peasant republic within the Holy Roman Empire and a member of the Hanseatic League . The district is located on the North Sea . It is embraced by the Elbe estuary to the south and the Eider estuary to
14500-519: The territory, but he failed, only forcing Adolf to accept his overlordship of Dithmarschen. Prince-Archbishop Hartwig II prepared a campaign into Dithmarschen, which, while religiously belonging to the Archdiocese of Bremen , and represented by its subsidiary chapter at Hamburg Concathedral , rejected secular overlordship from Bremen. He persuaded Adolf III to waive his claim to Dithmarschen, in return for being paid regular dues to be levied from
14625-590: The tide goes out. They use their muscular foot to dig into the substrate. To do this, the animal relaxes its adductor muscles and opens its shell wide to anchor itself in position while it extends its foot downwards into the substrate. Then it dilates the tip of its foot, retracts the adductor muscles to close the shell, shortens its foot and draws itself downwards. This series of actions is repeated to dig deeper. Other bivalves, such as mussels , attach themselves to hard surfaces using tough byssus threads made of collagen and elastin proteins. Some species, including
14750-558: The true oysters, the jewel boxes , the jingle shells , the thorny oysters and the kitten's paws , cement themselves to stones, rock or larger dead shells. In oysters, the lower valve may be almost flat while the upper valve develops layer upon layer of thin horny material reinforced with calcium carbonate. Oysters sometimes occur in dense beds in the neritic zone and, like most bivalves, are filter feeders. Bivalves filter large amounts of water to feed and breathe but they are not permanently open. They regularly shut their valves to enter
14875-406: The two halves detaching. The shell is typically bilaterally symmetrical , with the hinge lying in the sagittal plane . Adult shell sizes of bivalves vary from fractions of a millimetre to over a metre in length, but the majority of species do not exceed 10 cm (4 in). Bivalves have long been a part of the diet of coastal and riparian human populations. Oysters were cultured in ponds by
15000-402: The two valves and contract to close the shell. The valves are also joined dorsally by the hinge ligament , which is an extension of the periostracum. The ligament is responsible for opening the shell, and works against the adductor muscles when the animal opens and closes. Retractor muscles connect the mantle to the edge of the shell, along a line known as the pallial line . These muscles pull
15125-417: The young inside their mantle cavity, eventually releasing them into the water column as veliger larvae or as crawl-away juveniles. Most of the bivalve larvae that hatch from eggs in the water column feed on diatoms or other phytoplankton. In temperate regions, about 25% of species are lecithotrophic , depending on nutrients stored in the yolk of the egg where the main energy source is lipids . The longer
15250-533: Was built in the 14th century. While the outside was mainly rebuilt in the 19th century, inside one can still see Gothic architecture from the years 1250 to 1300. The paintings are among the most magnificent in Schleswig-Holstein, giving an impression of the former wealth of the farmers' republic. St. Jürgen church in Heide began as a chapel built in the 15th century. Due to conflicts in Dithmarschen, Meldorf lost its role as central meeting point. The people of northern Dithmarschen began to meet in 1447 "auf der Heide" ("on
15375-688: Was established in Heide. There are 800 students studying economics, electrical engineering, information technology, international tourism management, and law at the Fachhochschule Westküste (Fachhochschule West Coast). The Christian-Albrechts-Universität zu Kiel has an outpost in the Büsum-based Forschungs- und Technologiezentrum Westküste (Research and Technology Center West Coast), which researches coastal geology, coastal geography, and coastal protection. In 2004, 17,900 students were studying in Dithmarschen schools. In
15500-496: Was not just a sacral building; it was also the primary place for political meetings. Administration of spiritual and political matters was done by the same people in the same place, so little need for representative secular buildings arose. Political and religious life in Dithmarschen remained undivided until Schleswig-Holstein's integration into Prussia in 1867. In the flat marshland of Dithmarschen, church towers can often be seen from more than 10 kilometers away. Churches are built on
15625-490: Was supposed to belong to his Prince-Archbishopric of Bremen , to his brother Bernhard III , Duke of the younger Duchy of Saxony . In his new position of Duke of Saxony he held the Land of Hadeln , opposite of Dithmarschen on the southern bank of the river Elbe . Adolf III of Schauenburg , Count of Holstein , at enmity with the Ascanians , had de facto taken a loose possession of Dithmarschen. It fell to Bernhard to regain
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