Lake Ohrid, Albania / Republic of Macedonia
Coordinates	41°05′N 20°45′E
Primary outflows	Black Drin River
Catchment area	2,600 km² (1,000 mi²)
Basin countries	Albania, Republic of Macedonia
Max-length	30.4 km (18.9 mi)
Max-width	14.8 km (9.2 mi)
Surface area	358 km² (138 sq mi)
Average depth	155 m (508 ft)
Max-depth	288 m (940 ft)
Water volume	55.4 km³ (13 mi³)
Shore length1	87.53 km (54.38 mi) Macedonia: 56.02 km (34.8 mi); Albania: 31.51 km (19.58 mi)
Surface elevation	693 m (2273 ft)
Islands	none
Settlements	Ohrid, Struga (Macedonia); Pogradec (Albania)
1 Shore length is an imprecise measure which may not be standardized for this article.

Lake Ohrid (Macedonian: Охридско Езеро, Ohridsko Ezero Albanian: Liqeni i Ohrit) straddles the mountainous border between the southwestern region of the Republic of Macedonia and eastern Albania. It is the deepest and oldest lake in the Balkans, preserving a unique aquatic ecosystem with more than 200 endemic species that is of worldwide importance. The importance of the lake was further emphasized when it was declared a World Heritage site by UNESCO in 1979. However, human activity on the lake shores and in its catchment area is resulting in the ecosystem coming under stress. Image File history File linksMetadata Download high-resolution version (1262x812, 547 KB) en: Lake Ohrid da: Ohridsøen de: Ohridsee mk: Охридско Езеро sr: Охридско језеро Date: 22. ... The Black Drin (Albanian: Drini i Zi, meaning the black deer; Macedonian: Crn Drim) is a river in the Republic of Macedonia and Albania. ... A drainage basin is the area within the drainage basin divide (yellow outline), and drains the surface runoff and river discharge (blue lines) of a contiguous area. ... Anthem(s): (Transliteration: ) (English: ) Capital Skopje Largest city Skopje Official language(s) Macedonian, Albanian1 Government Parliamentary republic  - President Branko Crvenkovski  - Prime Minister Nikola Gruevski Independence From Yugoslavia   - Declared September 8, 1991  Area  - Total 25,333 km² (148th) 9,779 sq mi   - Water (%) 1. ... City motto : Coordinates Municipality : Ohrid municipality Elevation 695 m Population 55 749 Time zone  - Standard  - Summer (DST) CET (UTC+1) CEST (UTC+2) Founded Area code +389 046 Postal code 6000 Car plates OH Official Website www. ... Struga (in Macedonian: Струга, in Albanian: Strugë) is a town in the western part of the Republic of Macedonia, lying on the shores of Lake Ohrid. ... Church (Photo by Bernard Cloutier) Hotel Royal (Photo by Bernard Cloutier) Pogradec (Albanian: Pogradec or Pogradeci) is one of the southeastern cities of Albania. ... Anthem(s): (Transliteration: ) (English: ) Capital Skopje Largest city Skopje Official language(s) Macedonian, Albanian1 Government Parliamentary republic  - President Branko Crvenkovski  - Prime Minister Nikola Gruevski Independence From Yugoslavia   - Declared September 8, 1991  Area  - Total 25,333 km² (148th) 9,779 sq mi   - Water (%) 1. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... UNESCO logo UNESCO (United Nations Educational, Scientific and Cultural Organization) is a specialized agency of the United Nations established in 1945. ...

Geography

Map

Lake Ohrid is the deepest lake of the Balkans, with a maximum depth of 288 m (940 ft) and a mean depth of 155 m (508 ft). It covers an area of 358 km² (138 sq mi), containing an estimated 55.4 km³ of water. It is 30.4 km long by 14.8 km wide at its maximum extent with a shoreline length of 87.53 km, shared between Macedonia (56.02 km) and Albania (31.51 km). Image File history File links Prespa_lakes_map. ... Image File history File links Prespa_lakes_map. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Orders of magnitude (length) 1 E-13 m 1 E-12 m 1 E-11 m 1 E-10 m 1 E-9 m 1 E-8 m 1 E-7 m 1 E-6 m 1 E-5 m 1 E-4 m 1 E-3 m 1 E... To help compare different orders of magnitude and geographical regions, we list here areas between 100 km² and 1000 km². See also areas of other orders of magnitude. ...

Origin

Lake Ohrid and the Prespa Lakes belong to a group of Dessaret basins that originated from a geotectonic depression during the Pliocene epoch up to five million years ago on the western side of the Dinaric Alps. Worldwide, there are only a few lakes with similarly remote origins with Lake Baikal and Lake Tanganyika being the most famous. Most other, short-lived lakes have a life span of less than 100,000 years before they are eventually filled up with sediments. It is believed that in the case of Lake Ohrid this process was delayed by its large depth and small sediment input from filtered spring inflows. Moreover the Ohrid-Korca graben to the south of the lake is still tectonically active and might compensate sedimentation by subduction. Contrary to Lake Ohrid, Lake Prespa is likely to have turned dry several times in its history, as a result of its karstic underground.^[1] The Pliocene epoch is the period in the geologic timescale that extends from about 5 million to 1. ... Mt Orjen at the Bay of Kotor is the heaviest karstified range of the dinarids View of the central part of the Dinaric Alps (north=down) The Dinaric Alps or Dinarides (Italian: Alpi Dinariche; Croatian and Serbian: Dinaridi or Dinarsko gorje/Динариди or Динарско горје; Slovenian: Dinarsko gorstvo) form a mountain chain in... The references in this article would be clearer with a different and/or consistent style of citation, footnoting or external linking. ... Fishermen on Lake Tanganyika Lake Tanganyika is a large lake in central Africa (3° 20 to 8° 48 South and from 29° 5 to 31° 15 East). ... Map Satellite image Prespa is the name of two freshwater lakes in southeast Europe, shared by Greece, Albania, and the Republic of Macedonia. ... Karst topography occurs when a landscape is marked by underground drainage patterns. ...

Hydrology

Satellite image

The lake drains an area of around 2600 km² and is fed primarily by underground springs on the eastern shore (about 50% of total inflow), with roughly 25% shares from rivers and direct precipitation. Over 20% of the lake's water comes from nearby Lake Prespa, about 10 km (6 miles) to the southeast and at 150 m higher altitude than Lake Ohrid. The water leaves Lake Prespa trickling through underground watercourses in the karstic landscape, where it is joined by mountain range precipitation and eventually emerges in numerous springs along the eastern shore and below the water surface of Lake Ohrid. The water leaves Lake Ohrid by evaporation (~40%) and through its only outlet, the Black Drin River, which flows in a northerly direction into Albania and thus to the Adriatic Sea. The relatively dry, Mediterranean climate and the small drainage basin of 2600 km² (catchment/lake surface ratio of ~7) of Lake Ohrid results in a long hydraulic residence time scale of ~70 yr. ^[2][3][4] Image File history File links Ohrid_prespa_nasa. ... Image File history File links Ohrid_prespa_nasa. ... Map Satellite image Prespa is the name of two freshwater lakes in southeast Europe, shared by Greece, Albania, and the Republic of Macedonia. ... Karst topography occurs when a landscape is marked by underground drainage patterns. ... This article or section is in need of attention from an expert on the subject. ... The Black Drin (Albanian: Drini i Zi, meaning the black deer; Macedonian: Crn Drim) is a river in the Republic of Macedonia and Albania. ... A satellite image of the Adriatic Sea. ...

Physical and Geochemical Lake Properties

The water at the surface of Lake Ohrid moves predominantly in an anti-clockwise direction along the shore, as a result of wind forcing and earth rotation, similar to the Ekman-phenomenon known from oceans. In terms of vertical water exchange, convective mixing during winter cooling is the dominant process. However in an average winter only the top 150-200 meters of the lake are mixed, whereas the water below is stably stratified by salinity. The stability due to this salinity gradient allows complete convective mixing events only roughly once every 7 years.^[3][5] Paul Ekman (born 1934) is a psychologist and has been a pioneer in the study of emotions and facial expressions. ... Convection is the transfer of heat, by currents within fluids i. ... Stratification is the building up of layers of deposits, and can have several variations of meaning: Social stratification, is the dividing of a society into levels based on wealth or power. ...

Both in terms of nutrient concentration (4.5 μg L^-1 of phosphorus), as well as biological parameters Lake Ohrid qualifies as oligotrophic. Thanks to this oligotrophy and the filtered spring inflows, the water is exceptionally clear with transparencies to a depth of as much as 22 meters (66 feet). Despite the lack in annual deep water exchange from complete overturn or plunging rivers, dissolved oxygen never drops below ~6 mg L^-1.^[6][7] // Nutrients and the body A nutrient is any element or compound necessary for or contributing to an organisms metabolism, growth, or other functioning. ... An Oligotrophic refers to any environment which offers little to sustain life. ...

Fauna

While Lake Ohrid is special as such, by far the most spectacular quality is its impressive endemism. Similar to Lake Baikal or Lake Tanganyika, Lake Ohrid harbors endemic species covering the whole food-chain, from phytoplankton and sestile algae (20 species; e.g., Cyclotella fottii), over plant species (2 species; e.g., Chara ohridana), zooplankton (5 species; e.g., Cyclops ochridanus), cyprinid fish (8 species; e.g., Pachychilon pictus), to predatory fish (2 trout species; "Ohrid trout" Salmo letnica and "Belvica" Acantholingua ohridana) and finally its diverse endemic bottom fauna (176 species; e.g. Ochridagammarus solidus), with particularly large endemism among crustaceans, molluscs, sponges and planarians. Whereas the endemic species list cited above is based on morphological and ecological characteristics, some recent applications of molecular genetic techniques underline the difference of the fauna from common European taxa, as well as the old age of the lake.^[1][8][9] Endemic, in a broad sense, can mean belonging or native to, characteristic of, or prevalent in a particular geography, race, field, area, or environment; Native to an area or scope. ... The references in this article would be clearer with a different and/or consistent style of citation, footnoting or external linking. ... Fishermen on Lake Tanganyika Lake Tanganyika is a large lake in central Africa (3° 20 to 8° 48 South and from 29° 5 to 31° 15 East). ... Diagrams of some typical phytoplankton Phytoplankton are the autotrophic component of the plankton that drift in the water column. ... Photomontage of plankton organisms Plankton is the aggregate community of weakly swimming but mostly drifting small organisms that inhabit the water column of the ocean, seas, and bodies of freshwater. ... Genera (many, see text) The family Cyprinidae, named after the Greek word for goldfish, consists of the carps and minnows. ... Classes & Subclasses Branchiopoda Phyllopoda Sarsostraca Remipedia Cephalocarida Maxillopoda Thecostraca Tantulocarida Branchiura Pentastomida Mystacocarida Copepoda Ostracoda Myodocopa Podocopa Malacostraca Phyllocarida Hoplocarida Eumalacostraca The crustaceans (Crustacea) are a large group of arthropods (55,000 species), usually treated as a subphylum [1]. They include organisms such as lobsters, crabs, shrimp and barnacles. ... Classes Caudofoveata Aplacophora Polyplacophora - Chitons Monoplacophora Bivalvia - Bivalves Scaphopoda - Tusk shells Gastropoda - Snails and Slugs Cephalopoda - Squids, Octopuses, etc. ... Planaria sp. ...

Quite remarkably, exotic species do not seem to be a major issue in Lake Ohrid, although they have been recorded in small populations for several decades or exist in nearby rivers or lakes. The reason lies very probably in the ideal adaptation of the endemic species to the specific conditions in the lake, such as low nutrient availability, good living conditions in greater depth thanks to high water transparency and oxygen content, as well as subaquatic spring inflows supplying cool and oxygen-rich water.^[1]

Despite the exceptionally high level of endemism in Lake Ohrid (for example, ten of the seventeen identified fish species and as much as 80% of its molluscan fauna is endemic), a significant number of non-endemic species is found in Lake Ohrid. This includes species, which are mobile (e.g., via water birds) or migratory, such as the European eel.^[10] Classes Caudofoveata Aplacophora Polyplacophora - Chitons Monoplacophora Bivalvia - Bivalves Scaphopoda - Tusk shells Gastropoda - Snails and Slugs Cephalopoda - Squids, Octopuses, etc. ... Binomial name Anguilla anguilla (Linnaeus, 1758) The European Eel, Anguilla anguilla, is a snakelike fish. ...

The lakeshore reed beds and wetlands provide critical habitat for hundreds of thousands of wintering water birds, including rare and threatened species such as the Dalmatian Pelican, Ferruginous Duck, Swan, Spotted Eagle, and Eastern Imperial Eagle. Binomial name Pelecanus crispus Bruch, 1832 The Dalmatian Pelican (Pelecanus crispus) is a member of the pelican family. ... Binomial name Aythya nyroca (Güldenstädt, 1770) The Ferruginous Duck (Aythya nyroca) is a medium-sized diving duck. ... Genera and species Cygnus Bechstein 1803 C. cygnus C. buccinator C. columbianus C. (c. ... Binomial name Aquila clanga Pallas, 1811 The Greater Spotted Eagle (Aquila clanga), or just Spotted Eagle, is a large bird of prey. ... Binomial name Aquila heliaca Savigny, 1809 The Imperial Eagle (Aquila heliaca) is very similar to the Golden Eagle, but a little smaller (length 80 cm, wingspan 200 cm). ...

Socio-Economy

There are three cities on the lake's shores: Ohrid and Struga on the Macedonian side; Pogradec in Albania. There are also several fishing villages, although tourism is now a more significant part of their income. The catchment area of the lake has a population of around 170,000 people, with 131,000 people living directly at the lake shore (43,000 in Albania and 88,000 in Macedonia). The population in the catchment has increased greatly by 100,000 people in the last half century, putting the lake's fragile ecosystem under pressure. The historic monuments, as well as the pristine lake environment make the area around Lake Ohrid a prime site for tourism. In the 1980s more than 200’000 national and international tourists went on a literal pilgrimage to the Macedonian lake side every year. During the Yugoslav crisis and particularly after the interethnic conflicts within Macedonia in 2001 international tourism collapsed but has been slowly recovering during the past years. Even though many of the above visitors are staying for a weekend only, tourism makes an important share of local economy (~1 visitor/inhabitant).^[2][6] City motto : Coordinates Municipality : Ohrid municipality Elevation 695 m Population 55 749 Time zone  - Standard  - Summer (DST) CET (UTC+1) CEST (UTC+2) Founded Area code +389 046 Postal code 6000 Car plates OH Official Website www. ... Struga (in Macedonian: Струга, in Albanian: Strugë) is a town in the western part of the Republic of Macedonia, lying on the shores of Lake Ohrid. ... Church (Photo by Bernard Cloutier) Hotel Royal (Photo by Bernard Cloutier) Pogradec (Albanian: Pogradec or Pogradeci) is one of the southeastern cities of Albania. ... Yugoslavia (Jugoslavija in all South Slavic languages, Југославија in Serbian and Macedonian Cyrillic) is a term used for the three separate political entities that existed during most of the 20th century on the Balkan Peninsula in Europe. ...

Human Pressure

Shore habitats are under particular pressure from human activities. Particular threats are the building of tourist facilities directly at the shore, destroying of reed belts to gain cultural land and intense pollution close to the mouth of tributaries. Although the effects of these human impacts have not been evaluated in detail they are of great concern, as the shallow water sites are particularly rich in endemic bottom fauna and form important spawning grounds for several endemic fish species. Moreover reed belts have great importance for water birds.^[7]

Commercial fish yield, i.e. the two endemic trout species, has dropped significantly over the past decades, both in Macedonia and in Albania. The most probable reason is overfishing and possibly destruction of spawning grounds. Although there are regulations regarding fishing practice (e.g., minimal mesh size) and only a limited number of licensed fishermen, these rules are not followed consequently, as a result of the high market value of the endemic trout. As a reaction to the situation, fishing has been banned for the past two years, to help the fish population recover and to allow scientists collect further data. While most of the endemic fish species are non-migratory, the European eel spawns in the distant Sargasso Sea while its offspring return to the lake. Unfortunately, like in many European lakes, it is very unlikely today that eels can reach Lake Ohrid naturally and return to the Sargasso Sea, as a result of several hydropower dams on the Black Drin and the Drin River, both in Macedonia and Albania. As a result, eel found in Lake Ohrid are stocked populations.^[7][11] Binomial name Anguilla anguilla (Linnaeus, 1758) The European Eel, Anguilla anguilla, is a snakelike fish. ... An image of the distribution and size of eel larvae shows the approximate location of the Sargasso Sea. ... An image of the distribution and size of eel larvae shows the approximate location of the Sargasso Sea. ... The Black Drin (Albanian: Drini i Zi, meaning the black deer; Macedonian: Crn Drim) is a river in the Republic of Macedonia and Albania. ... Drin may refer to: The Drin river in Albania Drins, the group name of now banned chlorinated insecticides: aldrin, dieldrin and endrin, manufactured by Bayer AG. This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ...

Given the population growth over the past 50 years, a particular concern is the potential eutrophication of currently oligotrophic Lake Ohrid from increased pollution. Indeed, sediment cores show a ~3.5 fold increase in phosphorus concentration over the past century. On the one hand, shifts from endemic to common European species, which are better adapted to higher nutrient conditions, have already been observed close to polluted inflows. On the other hand, higher nutrient levels have reduced the water transparency, as well as the oxygen availability in the deep water and at the lake bottom, two properties which are requisite for the endemic flora and fauna. Still, the lake is in a comparably good state at the moment. However it may take more than a decade to see the effects of today's pollution level in the lake, because of its long water residence time. Moreover it was shown that the negative effects from eutrophication would be significantly amplified by global warming. Although there is time to react, computer simulations indicate that at least a 50 % reduction in phosphorus input must be reached to keep the deep water oxygenated for the next 50 years at predicted atmospheric warming. This aim could be reached by controlling household wastewater, which is by far the biggest phosphorus source at the moment. First steps in that direction have been taken by extending and improving the existing sewage system in Macedonia in the framework of a GEF (Global Environment Facility) program. The most important next task would be a solution for three remaining, severely polluted tributaries, one in Macedonia and two in Albania.^[6][7] Eutrophication is apparent as increased turbidity in the northern part of the Caspian Sea, imaged from orbit. ... An Oligotrophic refers to any environment which offers little to sustain life. ... Sediment is any particulate matter that can be transported by fluid flow and which eventually is deposited as a layer of solid particles on the bed or bottom of a body of water or other liquid. ... General Name, Symbol, Number phosphorus, P, 15 Chemical series nonmetals Group, Period, Block 15, 3, p Appearance waxy white/ red/ black/ colorless Atomic mass 30. ... Global mean surface temperatures 1856 to 2005 Mean surface temperature anomalies during the period 1995 to 2004 with respect to the average temperatures from 1940 to 1980 Global warming is the observed increase in the average temperature of the Earths atmosphere and oceans in recent decades. ... The Global Environment Facility (GEF), established by donor governments in 1991 to pre-empt politically more radically alternative models of conservation finance proposed at the Rio Earth Summit, helps developing countries fund projects and programs that are claimed to protect the global environment. ...

References

1. ^ ^a b c S. Stankovic, "The Balkan Lake Ohrid and its living world", Monographiae Biologicae, Vol. IX (Uitgeverij Dr. W. Junk, Den Haag, Netherlands, 1960)
2. ^ ^a b Z. Spirkovski, Z. Krstanovski, L. Selfo, M. Sanxhaku, V.I. Puka, "The Monitoring Programme of the Lake Ohrid Conservation Project", in Transboundary Water Resources in the Balkans: Initiating a Sustainable Co-Operative Network, ed. Jacques Ganoulis, I L Murphy, Mitja Brilly (Springer, 2000)
3. ^ ^a b A. Matzinger, Z. Spirkovski, S. Patceva, A. Wüest, "Sensitivity of ancient Lake Ohrid to local anthropogenic impacts and global warming" (Journal of Great Lakes Research 2006, 32: 158-179)
4. ^ A. Matzinger, M. Jordanoski, E. Veljanoska-Sarafiloska, M. Sturm, B. Müller, A. Wüest, "Is Lake Prespa jeopardizing the ecosystem of ancient Lake Ohrid?" (Hydrobiologia 2006, 553: 89-109)
5. ^ S. D. Hadzisce, "The mixo-phenomenon of Lake Ohrid in the course of the years 1941/42-1964/65 (in German)" (Proceedings of the International Association of Theoretical and Applied Limnology 1966, 16: 134-138)
6. ^ ^a b c A. Matzinger, M. Schmid, E. Veljanoska-Sarafiloska, S. Patceva, D. Guseska, B. Wagner, B. Müller, M. Sturm, A. Wüest, "Eutrophication of ancient Lake Ohrid: Global warming amplifies detrimental effects of increased nutrient inputs", (Limnology and Oceanography 2006, 52, in press)
7. ^ ^a b c d M. Watzin, V. Puka, T. B. Naumoski (eds), "Lake Ohrid and its watershed, state of the environment report" (Lake Ohrid Conservation Project. Tirana, Albania and Ohrid, Macedonia)
8. ^ H. Salemaa, "Lake Ohrid", in Speciation in Ancient Lakes, eds. K. Martens, B. Goddeeris, G. Coulter (Archiv für Hydrobiologie - Advances in Limnology 1994, 44: 55-64)
9. ^ J. Sell, Z. Spirkovski, "Mitochondrial DNA differentiation between two forms of trout Salmo letnica, endemic to the Balkan Lake Ohrid, reflects their reproductive isolation" (Molecular Ecology 2004, 13: 3633–3644)
10. ^ M.R. Frogley, R.C. Preece, "A faunistic review of the modern and fossil molluscan fauna from Lake Pamvotis, Ioannina, an ancient lake in NW Greece; implications for endemism in the Balkans", in Balkan Biodiversity: Pattern and Process in the European Hotspot, eds. Huw I. Griffiths, Jane M. Reed, Boris Kryštufek (Springer, 2004)
11. ^ Z. Spirkovski, personal information

External links

• Ohrid Municipality
• Macedonian Tourism portal
• Ohrid Information portal
• LakeNet Profile