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Opredelitev jezer ali ribnikov, še bolj pa mokrišč, se lahko razlikuje glede na zgodovinski čas opredelitve, države in znanstvenike. Kaj je "jezero" je še vedno predmet razprave. Po nekaterih definicijah bi bilo jezero sestavljeno iz sladke vode, za razliko od morij in oceanov, ki so slani. Ta definicija je napačna, ker ima Baltsko morje manj kot 4 g/l soli, Veliko slano jezero pa približno 250 g/l. Razvrstitev vodnega telesa kot jezera ali ribnika glede na njegovo krajevno ime v toponimiji tudi ni mogoča: isto vodno telo se včasih poljudno imenuje ribnik ali jezero ali jezero in morje. Meja med pojmoma jezero in ribnik je zabrisana Leta 1892 je Švicar François-Alphonse Forel, pionir limnologije (vede, ki se ukvarja z raziskavo celinski voda), jasno opredelil jezero. „Jezero“ je označil kot gmoto stoječe vode brez neposredne povezave z morjem, ki se nahaja v vdolbini v tleh, zaprti z vseh strani. Jezero je celinsko vodno telo, ki predstavlja kopičenje vode v depresiji v tleh kopnega in v nasprotju s celinskim morjem nima neposredne povezave s svetovnim oceanom, torej nima dotoka ali odtoka zaradi morskih tokov. Dotok in odtok sta običajno majhna v primerjavi s celotno količino vode v jezeru. V nasprotju z reko jezero nima naklona. Izraz celinsko jezero se uporablja za razlikovanje celinskih jezer od obalnih (obalna jezera, obalna brakična jezera ali jezera, ki nastanejo z nasipi ob obali), pa tudi za označevanje jezer nasploh. Jezero v smislu limnološke definicije je običajno veliko globlje od ribnika, tolmuna ali bajerja, tako da se lahko v dneh do mesecih razvije stabilna temperaturna stratifikacija. Pogostost njihovega mešanja se uporablja za razvrščanje jezer, saj ima tudi daljnosežne ekološke posledice . Po bolj pogosto uporabljeni definiciji so jezera le stoječa voda z globino več kot dva metra. Vendar pa je natančna razmejitev med jezeri in tolmuni/ribniki itd. nejasna in vedno subjektivna. Zato nekateri limnologi vsako depresijo, napolnjeno z vodo, imenujejo jezero. Za njihovo kategorizacijo bi bilo potem nepomembno, ali se jezero nenehno ali občasno polni z vodo. Pogovorno je dodelitev pogosto odvisna od slanosti, vendar to ni merilo. Čeprav jezero običajno vsebuje sladko vodo, obstajajo tudi velika slana jezera, kot npr Kaspijsko morje, Aralsko morje in Mrtvo morje. Izraz morje je v teh primerih zgolj zgodovinsko/kulturno opisni in gre za jezera. Obstajajo tudi jezera, ki vsebujejo sodo, na primer tista iz doline Rift v vzhodnoafriški dolini Rift, kot so jezero Nakuru, anatolsko jezero Van in nekatera jezera okoli jezera Neusiedl. Nadaljnjo definicijo je mogoče narediti z velikostjo. Najmanjša velikost jezera je približno en hektar. S pomočjo satelitskega opazovanja je bilo na zemlji določenih približno 100 milijonov površinskih jezer, s površino več kot en hektarja. Skupno pokrivajo površino več kot 300 milijonov hektarjev oziroma približno 2 % površine kopnega. V tem obsegu so všteta samo jezera povšine večje od enega hektarja. Delež preostalih majhnih jezer je bil dolgo podcenjen po številu: leta 2006 je globalni model z upoštevanjem vodnih površin manjših od hektarja. narejen na podlagi Paretovega zakona, podvojil prejšnjo oceno, ki je bila 304 milijone jezer na skupno 4,2 milijona kvadratnih kilometrov kopne površine. Podobne analize, ki temeljijo na popisu velikih umetnih jezov, so ocenile površino rezervoarjev na 0,26 milijona kvadratnih kilometrov. Globine svetovnih jezer so manj znane in se precej se razlikujejo glede na hidrogeološki kontekst in včasih tudi sezonsko. Tako ima jezero Loch Ness na Škotskem, povprečno globino 132 metrov, več kot štirkrat globje kot jezero Erie v Severni Ameriki, ki pa je 4500-krat večje po površini. Cael je v sodelovanju z Adamom Heathcoteom in David Seekellom razvil nov model za določanje volumna jezer po vsem svetu in z uporabo podatkov iz več študij so avtorji pokazali, da je število jezer na določenem geografskem območju v relaciji z matematičnim poteznim zakom: število jezer se s časom statistično zmanjšuje. Manjša ko so jezera, bolj so razporejena v grozd. Večja kot so jezera bolj so redka in izolirana. Majhnih jezer, manjših od 1 hektarja, je približno 100-krat več od jezer s povšino 10 hektarjev. Ta matematični zakon v kombinaciji z dodatnimi podatki kaže, da je bilo do zdaj število majhnih jezer podcenjeno. To vodi do ponovne ocene skupnega števila jezer na svetu in njihove površine navzgor, vendar z oceno njihove povprečne globine navzdol . Če so ta jezera dejansko plitvejša kot se je prej mislilo, verjetno oddajajo več metana, kot je bilo pričakovano. Njihova vloga kot ponorov ogljika bi bila manj pomembna od pričakovanega in njihov prispevek k globalnemu segrevanju večji od pričakovanega. S segrevanjem in zaradi povečanega vnosa organskih snovi zaradi evtrofikacije in erozije, ki jo povzročajo človekove dejavnosti, zlasti kmetijstvo, bi se ta prispevek lahko povečal dalje. Najnovejša ocena prostornine in globine temelji na teoriji perkolacije (Darcyjev zakon), pa tudi na topografskem matematičnem modelu Zemlje. Izračun nato da skupni volumen jezer 199.000 km3 in povprečno globino le 42 metrov. Te študije, ki temeljijo na matematičnem modelu, so splošne, vendar so tudi drugi dejavniki vplivali na število, prostornino in površino jezer na zgodovinskih ali geoloških časovnih lestvicah: to je na primer upad populacij bobrov, katerih jezovi so vse do zgodnjega srednjega veka vzdrževali veliko število vodnih teles. Nato je treba upoštevati tudi razvoj kmetijskega namakanja in črpanja podtalne vode ter nastanek številnih majhnih jezerskih jezer. Leta 1957 je britanski ekolog George Evelyn Hutchinson objavil monografijo z naslovom 'A Treatise on Limnology' (Razprava o limnologiji), ki velja za prelomno razpravo in klasifikacijo vseh glavnih tipov jezer, njihovega izvora, morfometrijskih značilnosti in razširjenosti. Hutchinson je v svoji publikaciji predstavil obsežno analizo nastanka jezer in predlagal splošno sprejeto klasifikacijo jezer glede na njihov izvor. Ta razvrstitev prepozna 11 glavnih tipov jezer, ki so razdeljeni na 76 podtipov. Enajst glavnih tipov jezer je: TEKTONSKA JEZERA VULKANSKA JEZERA LEDENIŠKA JEZERA REČNA JEZERA JEZERA NASTALA Z RASTAPLJANJEM KAMNINE - KRAŠKA JEZERA Takšno jezero zapolnjuje kotanjo, ki je nastala s površinskim raztapljanjem kamnine. Na območjih, ki jih prekriva topna kamnina, njena raztopina s padavinami in procejanjem vode običajno povzroči votline. Te votline se pogosto zrušijo in tvorijo vrtače, ki so del lokalne kraške topografije. Kjer podzemna voda leži blizu površine tal, bo vrtača napolnjena z vodo kot jezero raztopine. Če je takšno jezero sestavljeno iz velike površine stoječe vode, ki zavzema obsežno zaprto vdolbino v apnencu, se imenuje tudi kraško jezero. Manjša jezera, ki so sestavljena iz stoječe vode v zaprti depresiji znotraj kraškega območja, se imenujejo kraški ribniki oz. slovensko imenovani kali. Klasičnih primerov kraških jezer je veliko na kraških območjih ob dalmatinski obali Hrvaške in večjem območju Floride v ZDA. ZAJEZENA JEZERA ZARADI PLAZOV EOLSKA JEZERA Eolska jezera nastanejo zaradi delovanja vetra. Ta jezera najdemo predvsem v sušnih okoljih, čeprav so nekatera eolska jezera reliktne oblike tal, ki kažejo na sušno paleoklimo. Eolska jezera so sestavljena iz jezerskih kotanj, zajezenih s peskom, ki ga nanese veter; meddonalna jezera, ki ležijo med dobro orientiranimi peščenimi sipinami; in deflacijski bazeni, ki nastanejo zaradi delovanja vetra v predhodno sušnem paleookolju. Jezero Moses v Washingtonu v Združenih državah Amerike je bilo prvotno plitvo naravno jezero in primer jezerske kotline, zajezene s peskom, ki ga nanese veter. OBALNA JEZERA ŠOTNA JEZERA ANTROPOGENA JEZERA METEORITSKA JEZERA Literatura: Adrian Cho (2017), Svetovna jezera so plitvejša, kot se je domnevalo, namiguje matematična analiza; 17. marec 2017; študija, ki jo je vodil oceanograf MIT B.B. Cael na MIT (Massachusetts Institute of Technology), Cambridge, na podlagi predstavitve študije v The Volume of Earth's Lakes; Predsednica: Mary Silber, Univerza v Chicagu; Seja F12: Oblikovanje naravnih vzorcev in zemeljski podnebni sistem; Marčno srečanje APS 2017; 13.–17. marec 2017; New Orleans (Louisiana); B.B Cael, A. J. Heathcote et D. A. Seekell, « The volume and mean depth of Earth's lakes », Geophysical Research Letters, vol. 44, 13 janvier 2017, p. 209-218;
Cooper, C. M. (1993). Biological effects of agriculturally derived surface water pollutants on aquatic systems—a review. Journal of Environmental Quality, 22(3), str. 402-408; Hutchinson, G. E. (1957). A Treatise on Limnology. Vol.1, Geography, Physics, and Chemistry. New York: Wiley; Veillette, Julie; Mueller, Derek R.; Antoniades, Dermot; Vincent, Warwick F. (2008). "Arctic epishelf lakes as sentinel ecosystems: Past, present and future". Journal of Geophysical Research: Biogeosciences. 113 (G4): G04014; glej razlago: presihajopče jezero
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The definition of lakes or ponds, and even more so wetlands, may vary according to the historical time of the definition, countries and scientists. What a “lake” is is still a matter of debate. By some definitions, a lake would be made up of fresh water, unlike seas and oceans that are salty. This definition is incorrect because the Baltic Sea has less than 4 g / l of salt and the Great Salt Lake about 250 g / l. It is also not possible to classify a water body as a lake or pond according to its local name in toponymy: the same water body is sometimes popularly called a pond or lake or lake and sea. The boundary between the terms lake and pond is blurred In 1892, the Swiss François-Alphonse Forel, a pioneer of limnology (a science engaged in inland water research), clearly defined the lake. He described the 'lake' as a mass of standing water with no direct connection to the sea, located in a hollow in the ground, closed on all sides. A lake is an inland body of water that represents the accumulation of depressed water in land soils and, unlike the inland sea, has no direct connection to the world’s oceans, so it has no inflow or outflow due to sea currents. The inflow and outflow are usually small compared to the total amount of water in the lake. In contrast to the river, the lake has no slope. The term inland lake is used to distinguish inland lakes from coastal lakes (coastal lakes, coastal brackish lakes or lakes formed by embankments along the coast), as well as to denote lakes in general. A lake in terms of limnological definition is usually much deeper than a pond, pool, or pond, so stable temperature stratification can develop in days to months. The frequency of their mixing is used to classify lakes, as it also has far-reaching ecological implications. By more commonly used definition, lakes are just standing water with a depth of more than two meters. However, the exact demarcation between lakes and pools / ponds, etc. vague and always subjective. That’s why some limnologists call any depression filled with water a lake. For their categorization, it would then be irrelevant whether the lake is constantly or occasionally filled with water. Conversationally, allocation often depends on salinity, but this is not a criterion. Although the lake usually contains fresh water, there are also large salt lakes such as the Caspian Sea, the Aral Sea and the Dead Sea. In these cases, the term sea is merely historically/ culturally descriptive and refers to lakes. There are also soda-containing lakes, such as those from the Rift Valley in East Africa’s Rift Valley, such as Lake Nakuru, Anatolian Lake Van, and some lakes around Lake Neusiedl. Further definition can be made with size. The minimum size of the lake is about one hectare. About 100 million surface lakes, with an area of more than one hectare, have been identified on earth through satellite observation. In total, they cover an area of more than 300 million hectares or about 2% of the land area. Only lakes larger than one hectare are included in this scope. The share of the remaining small lakes has long been underestimated in number: in 2006, the global model took into account water areas smaller than a hectare. made on the basis of Pareto’s law, doubled the previous estimate of 304 million lakes to a total of 4.2 million square kilometers of land area. Similar analyzes, based on an inventory of large artificial dams, estimated the area of the reservoirs at 0.26 million square kilometers. The depths of the world's lakes are less known and vary considerably depending on the hydrogeological context and sometimes seasonally. Thus, Loch Ness in Scotland has an average depth of 132 meters, more than four times deeper than Lake Erie in North America, which is 4500 times larger in area. Cael, in collaboration with Adam Heathcote and David Seekell, developed a new model for determining the volume of lakes around the world, and using data from several studies, the authors showed that the number of lakes in a given geographical area is related to mathematical traction. statistically decreases over time. The smaller the lakes, the more they are arranged in a cluster. The larger the lakes the more sparse and isolated they are. Small lakes smaller than 1 hectare are about 100 times larger than lakes with an area of 10 hectares. This mathematical law, combined with additional data, shows that the number of small lakes has been underestimated so far. This leads to a reassessment of the total number of lakes in the world and their surface upwards, but by estimating their average depth downwards. If these lakes are actually shallower than previously thought, they are likely emitting more methane than expected. Their role as carbon sinks would be less important than expected and their contribution to global warming greater than expected. This contribution could be further increased by warming and by increasing the intake of organic matter due to eutrophication and erosion caused by human activities, especially agriculture. The latest estimate of volume and depth is based on percolation theory (Darcy’s law) as well as on the topographic mathematical model of the Earth. The calculation then gives a total lake volume of 199,000 km3 and an average depth of only 42 meters. These mathematical model-based studies are general, but other factors have also influenced the number, volume, and surface area of lakes on historical or geological time scales: for example, declining beaver populations whose dams maintained many until the early Middle Ages. number of water bodies. Next, the development of agricultural irrigation and groundwater abstraction and the emergence of many small lake lakes must also be taken into account. In 1957, British ecologist George Evelyn Hutchinson published a monograph entitled ‘A Treatise on Limnology’, which is considered a groundbreaking discussion and classification of all major lake types, their origins, morphometric characteristics and distribution. In his publication, Hutchinson presented a comprehensive analysis of lake formation and proposed a generally accepted classification of lakes according to their origin. This classification identifies 11 main types of lakes, which are divided into 76 subtypes. The eleven main types of lakes are: TEKTONIC LAKES VOLCANIC LAKES GLACIER LAKES RIVER LAKES LAKES FORMED BY STONE DISSOLUTION - KARST LAKES Such a lake fills a hollow formed by the surface dissolution of rock. In areas covered by soluble rock, its solution with precipitation and water seepage usually causes cavities. These cavities often collapse and form sinkholes that are part of the local karst topography. Where groundwater lies close to the ground surface, the sinkhole will be filled with water like a lake of solution. If such a lake consists of a large area of standing water, which occupies an extensive closed depression in the limestone, it is also called a karst lake. Smaller lakes, which consist of standing water in a closed depression within the karst area, are called karst ponds or. Slovenian called kali. There are many classic examples of karst lakes in the karst areas along the Dalmatian coast of Croatia and a larger area of Florida in the USA. LAKES DAMAGED BECAUSE OF landslides Sources and literature: Adrian Cho (2017), Svetovna jezera so plitvejša, kot se je domnevalo, namiguje matematična analiza; 17. marec 2017; študija, ki jo je vodil oceanograf MIT B.B. Cael na MIT (Massachusetts Institute of Technology), Cambridge, na podlagi predstavitve študije v The Volume of Earth's Lakes; Predsednica: Mary Silber, Univerza v Chicagu; Seja F12: Oblikovanje naravnih vzorcev in zemeljski podnebni sistem; Marčno srečanje APS 2017; 13.–17. marec 2017; New Orleans (Louisiana); B.B Cael, A. J. Heathcote et D. A. Seekell, « The volume and mean depth of Earth's lakes », Geophysical Research Letters, vol. 44, 13 janvier 2017, p. 209-218; Cooper, C. M. (1993). Biological effects of agriculturally derived surface water pollutants on aquatic systems—a review. Journal of Environmental Quality, 22(3), str. 402-408; Hutchinson, G. E. (1957). A Treatise on Limnology. Vol.1, Geography, Physics, and Chemistry. New York: Wiley; Veillette, Julie; Mueller, Derek R.; Antoniades, Dermot; Vincent, Warwick F. (2008). "Arctic epishelf lakes as sentinel ecosystems: Past, present and future". Journal of Geophysical Research: Biogeosciences. 113 (G4): G04014; see definition: intermittent lake |
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Burger Landmarks / MojaSlovenija.si | _ Digitalizacija dediščine: (c) Boštjan Burger, (1993) 1996-2024 |