Limnology

Lake Urmia

Content Cover Image

Lake Urmia from satellite, with glistening mineral strands. Source: NASA

Lake Urmia is a shallow perennial inland salt water body in northwestern Iran. This lake is the second largest in the Middle East, measuring roughly 5000 square kilometers in extent. In the Mid-East only the Dead Sea is a larger hypersaline body.

Lake Urmia is considered an endorheic basin, meaning there is no outflow discharge to any river or ocean. The drainage basin consists chiefly of arid and semi-arid lands including part of the Dasht-e Kavir of the Iranian Plateau.

Also known as Lake Orumiyeh, this lacustrine unit is a significant internationally recognized natural area and is designated as a RAMSAR site and UNESCO Biosphere Reserve. Temperatures in the lake basin vary dramatically, ranging from minus 20 degrees Celsius in the winter to 40 degrees Celsius in summer.

The locale boasts a rich ancient history including early Neolithic farming, agricultural irrigation innovations and livestock tending. Iron Age settlements here brought cultures that made significant contributions in art, wheeled vehicle technology and metallurgy. Recent activities in dam construction and water diversions by the government of Iran jeopardize the future existence of the shallow Lake Urmia.

Hydrology and Chemistry

caption Stranded ship evidencing recent desiccation of
Lake Urmia. Source: Harrijet News

The surface area of Lake Urmia has widely varying estimates of size, depending on the date of reportage and season, due to the shallowness of the lake, seasonality of flow and desiccation trend in recent times. Reported  water surface area in the literature ranges from 4700 to 6000 square kilometers. Correspondingly the mean depth of the lake has a variably reported value of 5.0 to 6.1 meters. The lake volume measures approximately 29.4 cubic kilometers. Lake Urmia is ranked as either the third or fourth largest saline lake in the world, depending on sources consulted and the date of ranking. At present, it is clearly the largest lake of any type in the Mid-East region of the world.

The lake measures approximately 140 kilometers long (approximate north-south dimension) by about 80 km wide, and is situated with surface level around 1280 meters above mean sea level. The southern part of the lake is the deepest, with maximum depth reaching only about 15 meters. The southern reaches of Lake Urmia are also most saline, due to freshwater inflows being chiefly in the north, especially at the Talkerud alluvial braid plain. There are extensive areas of exposed strandline sediment visible in the NASA satellite imagery, prominent along the southeast and northwest shores. The ancient Persians noted how these fringes glisten and named the lake Chicast, meaning glittering. Framing the western and southern shores are salt flats and fan deltas.

caption Shrinkage of Lake Urmia. Outside dashed line is
Pleistocene perimeter; +++ line is 1965 shoreline;
blue lake is 1977 size. @ Alexander Hogan

Riverine inflow to Lake Urmia is strongly seasonal, typically driving lake levels to fluctuate one to two meters within an annual cycle. During spring snowmelt from the higher reaches of the basin, the Simineh and Talkheh Rivers discharge a flow of about 57 cubic meters per second to the lake; however, by midsummer, that combined influx falls to an influx of approximately two to four cubic meters per second, and the lake surface drops. Moreover, from 1994 to 2004 there was a precipitous decline in water depths, with lake levels falling about five meters.

The lake is classified as a hypersaline body due to its extreme salinity; furthermore, Lake Urmia is grouped within saline lakes having chloride waters, i.e. those that dissolve sodium chloride from rock salt beds. Along with high salinity, this Iranian lake has extreme bromine levels reported in the range of 3400 to 3900 milligrams per liter; on the other hand, boron concentrations are rather low.

Aquatic Ecology

caption Brine shrimp Artemia salina occurs in Lake Urmia. Source: Hans Hillewaert

Due to the lake’s hypersalinity no species of fish are presently sustained; however, at least seven amphibian taxa occur in Lake Urmia and its tributaries, notably including the Lake Urmia newt (Neurergus crocatus), a vulnerable species inhabiting rivers draining to the lake. Micrococcus species and masses of green diatoms are found in Lake Urmia. Brine shrimp are organisms that occur only in saline lakes, and not at all in ocean environments; in Lake Urmia are found the species Artemia urmiana and A. salina. Of historical note, Lake Urmia was the first location on Earth where Artemia were recorded in the year 982 AD.

Lake Urmia was inscribed as a Biosphere Reserve on 23 June, 1975; the locale is also a  National Park in the nation of Iran. This vast hypersaline lake holds many islands, and is surrounded by extensive brackish marsh. The lake is fed by rainfall, springs and streams and subject to seasonal variation in level and salinity. The locale is designated as Ramsar site number 38.

Present day lake floor sediments are chiefly aragonite pelletal laminite/mudstones. The laminites result form seasonal biologically mediated precipitation of aragonite. Moreover, as nutrient and salinity levels dictate, the lake surface layer evinces a green algae bloom dominated by Enteromorpha intestinalis with admixed species of the genera Tetraselmis and Dunaliella. Brine shrimp subsequently graze the algal growth, and they also ingest precipitating aragonite.

In the hyposaline lagoons above Lake Urmia are found Spirulina maior, Cocconeis placentula, Amphora brevipes and A. coffaeiformis.

Basin Terrestrial Ecology

See main article: Eastern Anatolian montane steppe

Eastern Anatolian montane steppe (classified by the World Wildlife Fund as PA0805) is the ecoregion characterization of the Urmia drainage basin, whose catchment area totals 57,000 square kilometers. The western side of the basin is the steepest, with peaks rimming that edge of the catchment reaching heights of 3350 meters. The entire area including the lake itself is an important migratory area for many bird species, notably flamingo, which may number 40,000-80,000 pairs. Also present are migratory ibis, pelican, spoonbill, stork, shelduck, avocets, stilts, and gull species; the entire region is a key migration corridor for north-south movement of birds, much like the Strait of Gibraltar, in providing a passage that requires a minimum of long distance flight across the Mediterranean Sea. The brackish marshes support reeds and large breeding colonies for many avian species; more than 210 distinct avian taxa are resident or migrant to Lake Urmia.

There are 27 mammalian species present in the montane steppe of this catchment basin. The terrestrial part of the catchment is a significant repository for many fruit and nut trees. Within the Eastern Anatolian montane steppe there are a number of endemic taxa including Prunus kotschyi, P. cardauchorum, Crateagus davisii, Pyrus hakiarica, Pyrus salicifolia var. serrulata.

Ancient history

caption Naghade Hasanloo archaeological site south of Lake Urmia;
site was occupied from Neolithic to the Early Iron Age
ending 350 BC Source: Amin Gholizad
Both Neanderthals as well as Homo sapiens are known to have inhabited the Lake Urmia region in prehistoric times, with likely diminishing of Neanderthals toward the end of the Eemian period.

Settlements around Lake Urmia featured prominently in the early civilizations of west Asia. Some of the earliest people with a vestige of recorded history to inhabit the Lake Urmia region were the Kura-Araxes culture, whose horizon is dated from 3400 to 2000 BC. These early farmers were noted for their skills in livestock keeping, irrigation technology, precocious metal-working and distinctive geometric red-black pottery. With a cultural center north of Lake Urmia, these peoples extended their domain around and south of Lake Urmia. It is likely that future archaeological work will yield more traces of their culture around Lake Urmia, due to their building of distinctive round or square mud structures.

Arriving from the east came nomadic Gutians, a fair-haired people, who reached their apex when they overran Mesopotamia in  2150 BC. These Guti people faded into obscurity with few artifacts having been recovered in the homeland around Lake Urmia.

By approximately 1000 BC a people known as the Manneans became established in the Lake Urmia region, who began to flourish about 850 BC with their capital at Zikirtu. At some point, at least by the ninth century BC, the Urartu people entered the region from the north, erecting a chain of Iron Age fortresses; they engaged in sophisticated canal irrigation works and development of early wheeled vehicles, apparently living peaceably alongside the Manneans. As noted by Hogan the Urartu had influences on architecture centuries later, for example,  in the design of the famed Tomb of Cyrus. The Urartu leader Menua is credited with the bulk of the systematic expansion south, with erection of over 60 fortresses around his era.

The ancient Mannean city of Andia has been ascribed to a location on the northwestern shore of the lake, and the city of Zikirtu is thought to have been on the eastern shore; both of these cities are associated with the Kingdom of Andia of the Mannean civilization (850-700 BC) .

The invading Assyrians led by Sargon II fiercely attacked the Manneans and Urartu people about 714 BC, and subsequently sacked and plundered much of their civilization. The ferocity of the Assyrians was attested by their own scribes who depicted in detail the heavy cavalry and their attendant massacres of Mannean populations.

Records of the movements of the armies of Sargon II in reaching Lake Urmia give a glimpse of the state of forestation at that time. Army records indicate that much of the region was densely forested, implying that major deforestation in this region took place sometime subsequent to the 8th century BC; this loss of forest was probably a joint result of timber harvests as well as climate changes and desiccation that were likely taking place in this region as early as the first millennium BC. This hypothesis is consistent with global warming that began at least as early as 3000 years before present, driven initially by carbon release to the atmosphere of the deforestation.

Final destruction of the Manneans was wrought by conquering Matiene peoples, giving rise to another historical name for the lake as Lake Matiene. Ancient Greek and Roman influences were noted in the Lake Urmia area, in their respective periods of ascendancy in the wider region. Greek influence began with the wider Persian conquests commencing with the advance of Alexander the Great into Persia in 330 BC.

Twenty-First Century Protests

caption Example of many protest art creations urging
protectingLake Urmia. Source: Fred Petrossian

At present, a number of major human settlements are scattered around the lake shoreline, with the local human population numbering in the millions. Recent and ongoing protests as of September, 2011 are occurring in cities such as Sulduz, Urmia, Ardabil, Tabriz, Marand, Maragha, and Qoshachay, involving massive demonstrations against Iranian governmental policies that are exacerbating the desiccation of Lake Urmia. The government of Iran does not have a strong record of archaeological and environmental protection, as evinced elsewhere by the Sivand hydroelectricy project threatening flooding at the ancient Persian capital Pasargadae, which includes the iconic Tomb of Cyrus.

As of mid-2011, protesters are using peaceful marches to assert that the Iranian government actions of dam building and water diversions are causing rapid shrinkage of the lake. Government responses have included arrests of hundreds of marchers, firing of live ammunition, wounding of many protesters and killing of at least one Lake Urmia conservation campaigner. Furthermore, the police have taken over at least one news station in Tabriz following a major protest, in order to hamper dissemination of violent news events of the protests. Some news reports have indicated that police have exacted retribution on conservation protesters by raiding homes, arresting residents and confiscating personal property. The geographic range of the protest is quite large, extending into Turkey and Azerbaijan; this wide geographic concern is both due to (a) potential broad scale dispersion of lakebed fine particulate matter as the lake desiccates, and (b) ethnic resonance of concerns of Azerbaijani peoples who are native to the lake perimeter.

References

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  • M. Chahin. 2001. The kingdom of Armenia: a history. Psychology Press. 350 pages
  • Amin Eimanifar and Feridon Mohebbi. 2007. Urmia Lake (Northwest Iran): a brief review. Saline Systems. 3: 5. Published online 2007 May 16. PMCID: PMC1884160 BioMed Central Ltd.
  • Ulrich Theodore Hammer. 1986. Saline lake ecosystems of the world. Springer. 616 pages (Google eBook)
  • C. Michael Hogan. 2008. Tomb of Cyrus. The Megalithic Portal. ed. A. Burnham, Jan 19, 2008
  • Henry H. Howorth. 1901. The Early History of Babylonia, The English Historical Review, Vol. 16, No. 61 (Jan. 1901)
  • Hurriyet News. 2011. Rally protesting Iran over Lake Urmia turns violent. Sept 1, 2011
  • N.Karmi. 2011. Iran's largest lake turning to salt. Associated Press 25 May 2011.
  • Robert Mackey. 2011. Protests in Iran Over Disappearing Lake. New York Times. 30 August, 2011
  • Colin Renfrew. 2003. Time Depth, Convergence Theory, and Innovation in Proto-Indo-European. Languages in Prehistoric Europe. ISBN 3-8253-1449-9
  • Olaf Alfred Toffteen. 1908. Researches in Assyrian and Babylonian geography (Google eBook) University of Chicago Press. 60 pages
  • John K. Warren. 2006. Evaporites: sediments, resources and hydrocarbons. Birkhäuser. 1035 pages
Glossary

Citation

Hogan, C. (2011). Lake Urmia. Retrieved from http://www.eoearth.org/view/article/170051

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