Doiran Lake (Macedonian: Доjранско Езеро, Dojransko Ezero; Greek: Λίμνη Δοϊράνη, Límni Dhoïráni), also spelled Dojran Lake is a lake with an area of 43.1 km2 (16.6 sq mi) shared between the Republic of N. Macedonia (27.3 km2, 10.5 sq mi) and Greece (15.8 km2, 6.1 sq mi).
To the west is the city of Nov Dojran (Нов Дојран), to the east the village of Mouries, to the north the mountain Belasica and to the south the Greek town of Doirani. The lake has a rounded shape, a maximum depth of 10 m (33 ft) and a north-to-south length of 8.9 km (5.5 mi) and 7.1 km (4.4 mi) at its widest, making it the third largest lake partially in the Republic of N. Macedonia after Lake Ohrid and Lake Prespa. The lake was on the southern line of the Macedonian front during World War I, and its southern shore became the site of the various battles between allied troops and Bulgarian troops in 1916, 1917 and 1918. A monument to one of the battles and two cemeteries for Greek and British troops stand on a hill a few hundred metres south of the lake. Due to the overuse of the lake’s water for agricultural purposes in recent years, Doiran’s water nearly drained out, but the disaster was avoided after the countries took measures to replenish and sustain the lake’s water levels. Frequent and heavy rainfalls, in last years, also helped restoring the lake’s water levels.
The mud of the Dojran Lake is mending. It’s specifically beneficial in healing of the muscles and bones. This is very usual site on Dojran shores. People cover themselves with mud and bake on the sun. They believe in its healing powers.
It’s good for healing sinusitis. The algae that is being produced in the lake can take care of any sinusitis inflammation you have. Just rinse the nose thoroughly with lake water and you can drink cold beer and eat frozen ice cream. In this study the mineralogical and geochemical characteristics of Lake Dojran surficial (0–5, 5–10, 10–15 cm) sediments were studied in order to determine their suitability for use as potential raw material in balneotherapeutic treatments. X-ray powder diffraction (XRD) and inductively coupled plasma mass spectrometry (ICP-MS) analyses were performed, and thereupon chemical index of alteration (CIA) and enrichment factor (EF) values were calculated. The XRD results revealed close association of sediment mineralogy with the prevailing metamorphic, volcanic and igneous rocks of the region surrounding Lake Dojran. CIA values of around 67% suggest a moderate degree of weathering in the lake catchment area. According to the EF value results, surficial Lake Dojran sediments are little enriched with Co, Cr, Cu, Pb, and Zn, moderately enriched with Au, Ni and Sb, moderately severely enriched with Au, severely enriched with Sb and very severely enriched with As. This elemental enrichment likely originates fromvarious different geogenic (geological background and polymetallic mineralization) and anthropogenic (tourism, traffic, coatings, untreated wastewater discharge and agrochemicals) sources. The abundances of the major elements, trace elements and rare earth elements (REEs) were almost constant, changing very little throughout the surficial (0–5, 5–10, 10– 15 cm) sediments. Comparison of sediment trace element concentrations with consensus-based threshold effect concentration (TEC) and probable effect concentration (PEC) values showed that lake biota may be under threat of contamination with As, Cu and Ni. Given the present results, we cannot recommend/confirm the application of Lake Dojran dark mud sediment in balneotherapeutic treatments.
First exploitation of the lake water was in 1808 with construction of a 1300 m long irrigation canal. The first documented water level in Dojran was 150 m a.s.l. registered in 1810 (Stojanov,2002). Water level oscillations in the first half of XX century motivated N. Macedonian (Yugoslavia) and Greek authorities in 1956 to regulate water level that was to be maintained between 144.8 and 147.34 m a.s.l. In the period 1952–1988, the water level was at an average altitude of 146.45 m a.s.l. (Fig.2). During the period 1983-1987 the water level fluctuated mainly above the agreed minimum level. Due to prolonged drought that started in 1988, as well as anthropogenic impacts, the water level had been continually dropping reaching the minimum level of 141.76 m a.s.l. The anthropogenic activities were mainly connected to water use for agricultural sector. Namely, from 1988, according to an agreement between the two countries, Greece started using water from the lake for agricultural irrigation, through Djol-Ajak canal on the Greek side. For the period 1988- 2002 the average water level decrease was 34 cm annually. In 2002 the volume of water dropped to about 60×106 m3 , presenting the water loss of almost 80 % compared to the 1956 maximum volume of 280×106 m3. In this period area of the lake decreased from about 41.8 to 29.5 km2 (Bonacci et al., 2015), resulting in the recession of the lake’s shore up to 100 m from the main settlements, the disappearance of much of the western littoral zone and significant biodiversity loss (Ristevski, 1991; Georgievska and Matevska, 1996; Griffiths et al., 2002). This sudden drop in
water level accelerated the lake towards a greater eutrophic state (Sotiria and Petkovski, 2004).
Dojran Lake valley is one of the warmest regions in this part of the Balkans (Popovska, 2013). The climate is Sub-Mediterranean and comparing to the surrounding semi-continental climate has higher average minimum and maximum monthly air temperatures and lower precipitation sums. The climate of Dojran region is also influenced by the lake water surface and surrounding mountains. The southern part of the catchment is open to the Thessaloniki Plain and the Aegean Sea, allowing direct influence from the Mediterranean climate.
Evaporation from the shallow Dojran Lake is an important natural determinant of its water balance. Bonnaci and colleagues (2010, 2015) found a relation between the temperature increase – that had an increasing trend for the period 1951-2010 (Fig.4) – and the lake’s hydrologic regime: when air temperature increases, the water level decreases due to the water loss by evapotranspiration and evaporation from the lake water surface. Even though the period 1989-2002 when the lake water level significantly decreased was also characterized by the intense prolonged drought (Myronidis et al., 2012), Bonacci et al. (2015) showed that, unlike temperature, annual precipitation did not play significant role in the lake water level behaviour. Besides being affected by natural phenomena and climate change, in particular temperature increase, the lake water decrease in the late XX century was also strongly affected by intense water extraction for irrigation. The difference in computed – using water balance hydrological modeling – and recorded water levels show water volume loss of about 200 million m3 which can be linked to water abstraction (Gjesovska, 2013).
Since Dojran Lake can be classified as highly sensitive to climate and anthropogenic changes (Francke et al., 2013), it is realistic to expect more challenges for the lake water resource management in the future. Namely, Dojran Lake needs to adapt to climate change expected in the near future.
According to the European Community Habitats Directive 92/43/EEC, Lake Dojran has the following habitats:
1. Oligothropic to mesotrophic standing waters with vegetation of the Littorelletea uniflorae and/or Isoeto-Nanojuncetea type.
2. Natural eutrophic lakes with Magnopotamion (pondweed) or Hydrocharition (freefloating surface communities) type of vegetation. This habitat type is abundant in Dojran with extensive reedbeds with species such as: Phragmites australis (common reed), Scripus lacustris (club-rush), Typha angusifolia (narrow-leaf cattail), Sparagnium erectum (bur-reed). Parts where the lake water withdrew transformed into pastures with commonly found Paspalum distichum (knotgrass).
3. Mediterranean tall humid herb grasslands of the Molinio-Holoschoenion type.
4. Riparian mixed forests of Quercus robur (pedunculate oak), Ulmus Laevis (elm) and Ulmus minor (field elm), Fraxinus excelisior (ash) or Fraxinus anguistifolia (narrow leafed-ash) along the rivers.
5. Salix alba (white willow) and Populus alba (poplar) galleries.
On the Greek side an important habitat is the Mouries Woods on alluvial deposit. Forest communities present in the wider watershed zone include: Coccifero-Carpinetum orientalis (sub-Mediterranean pseudomaquis composed of shrub-like evergreen oak – Quercus coccifera and oriental hornbeam – Carpinus orientalis), Quercetum conferatae-cerris (oak and Turkey oak forests), Orno-Quercetum petraeae (Sessile oak-hornbeam forests), Fagetum (sub)montanum (mountain
beech), endemic community Juglando-Platanetum orientalis (walnut-plane forest), Carpinetum orientalis-Philyrietosum mediae, Carpinetum orientalis-Quercetum sessiliflorae (forests of oriental hornbeam and some oak species, such as Italian oak – Quercus frainetto).
Commercially most important species in Dojran are fish, including the following species: roach – Rutilus rutilus, carp – Cyprinus carpio, Vardar chub – Leucaspius delineatus, rudd – Scardinius erythrophtalmus, tench – Tinca tinca, bleak – Alburnus alburnus makedonicus, bitterling – Rhodeus sericeus amarus, Macedonian roach – Pachychilon makedonicus, Gudgeon – Gobio gobio balanicus, Balkan barbel – Barbus peloponnesius, Prussian carp – Carassius gibelio; Vardar spined loach – Cobitis vardarensis, catfish – Silurus glanis, eel – Anguilla Anguilla, perch – Perca fluviatilis, river blenny – Salaria fluviatilis, and the endemic Dojran loach – Sabanejewia aurata doiranica. Three of the above fish species are included in Annex II of Dir. 92/43/EEC (under the species names Barbus plebejus, Sabanjewia aurata and Cobitis taenia), Pachychilon macedonicus and Gobio gobio balcanicus are in the Hellenic Red Data Book and Salaria fluviatilis is included in Annex III of the Bern Convention. Within the ecosystem of the lake Doiran, amphibians consist of ten species (Sidorovska et al. 2001; Dzukic et al. 2001; Sidorovska et al. 2003). Frog species Rana balcanica and newt Triturus karelinii, as well as the subspecies Pelobates syriacus balcanicus, Bombina variegata scabra and Triturus vulgaris graecus, are Balkan endemics. Newt Triturus vulgaris graecus manifests as a neotenic population only in the Dojran Basin, while the Greek marsh frog – Rana balcanica, has its most abundant population within the Lake. The Balkan spadefoot toad – Pelobates syriacus balcanicus, was described from a specimen collected from the shore of Dojran Lake. It should
be noted that Tristurus karelinii and Pelobates syriacus (both at the species level) are included in Annex II of Dir. 92/43/EEC and Annex II of the Bern Convention, accordingly.
Other vertebrates include 23 reptile species. The subspecies of European pond turtle – Emys orbicularis hellenica, the subspecies of Kotschy’s gecko – Cyrtodactylus kotschyi skopjensis, the subspecies of European copper skink – Ablepharus kitaibelii stepaneki, and the subspecies of Erhard’s wall lizard – Podarcis erhardii riveti are Balkan endemics. The sand boa – Eryx jaculus turcicus, was first recorded on the Balkan Peninsula at a location within the Dojran Basin. This species is the only European representative of the large family of boas. There is also Emys orbicularis, included in Annex II of Dir. 92/43/EEC, lizards Lacerta viridis and Podarcis taurica included in Annex II of the Bern Convention.
Dojran has 87 bird species (Dangel 1973; Dimovski and Matvejev 1955; Matvejev and Vasic 1973; Micevski 1991). There are about 36 bird species abundant in the area all included in Annex II and III of the Bern Convention. Fifteen of these species are also included in the Birds Directive 79/409/EEC. Dalmatian Pelican Pelecanus crispus and white-headed duck Oxyura leucocephala are threatened species and their presence renders the site as an Important Bird Area for both countries. Other bird species include: great white pelican Pelecanus onocrotalus, purple heron Ardea purpurea, Pygmy cormorant Phalacrocorax pygmeus, wader Recurvirostra avosetta, harrier Circus aeruginosus, shrike Lanius nubicus, among others. There are 53 mammal species in the Dojran basin (Petrov 1992; Krystufek et al. 1992; Krystufek and Petkovski 1999; and Petkovski et al., 2001). Of these, only a few species are directly related to the water biotope of the lake. The most common mammal is the weasel Mustela nivalis, included in Annex III of the Bern Convention.
Other terrestrial animals include moths and butterflies (Lepidoptera). Thurner (1964) recorded 103 species from the Family Noctuidae (noctuid moths) within the basin, including the national endemic – Cosmia rhodopsis, and two subtropical species: Scotia spinifera and Mythimna vitellina. Daniel (1964), in his study of the Families Bombycidae (silk moths) and Sphingidae (hawk moths), recognised 56 species in the basin, including the four Dojran endemic subspecies: Zygaena
purpuralis doiranica, Zygaena carniolica paeonica, Zygaena ramburi europensis and Cosmotriche potatoria. The Family Geometridae (geometer moths) is represented with 89 species in the Dojran basin (Pinker, 1968). The group Microlepidoptera (small moths) is most numerous in the Dojran basin, comprising 192 species (Klimesch, 1968), including the Dojran endemic species – Cnephasia klimeschi. Finally, Thurner (1964) and Schaider and Jaksic (1989), investigating the butterflies of the Families Hesperiidae, Papilionidae, Pieridae, Lycaenidae and Nymphalidae, recognised 86 species, which is 43% of the diurnal butterfly fauna of N. Macedonia. The total number of recorded
species (526) from the Order Lepidoptera shows an enormous diversity within a relatively restricted area. The diurnal butterfly species Lycaena dispar is included in Annexes II and IV of the Habitats Directive 92/43/EEC.
Dojran dragonfly diversity presents 80% the total dragonfly fauna of N. Macedonia. Karaman (1981) recorded 39 species and Peters & Hackethal (1986) added three new species. The dragonfly species Coenagrion ornatum is included in Annexes II of the Habitats Directive. The lake water is also rich in biodiversity and the aquatic fauna includes numerous species. Within molluscs, the aquatic gastropods consist of 21 species, including the Dojran endemic snail – Graecanatolica macedonica (Roding 1966; Sapkarev 1975; Stankovic 1985, 1991), which is considered extinct from 2000. However, some shells of this species were collected in 2009 and 2015 (Fischer et al., 2009; REC, 2015). These are either subfossil shells washed out from sediment, or it is possible that the species may have survived in a small groundwater source and that species is extant (iucnredlist.org, 2013). The molluscs from the class Bivalvia are represented by
five species, including Dreissena polymorpha, whose dead shells are present in large masses along the current shoreline zone of the lake. Within segmented worms (Annelid), Branchiobdelidae were occurring as ectobionts of the Balkan
river crayfish Astacus astacus balcanicus, with 15 species (Georgevitch, 1955). Four branchiobdelid species have been accepted as Dojran endemics (Petkovski et al., 2003): Branchiobdella capito, Cambarincola dojranensis, Pterodrilus prion, and Xironodrilus crassus. However, the drastic reduction in the populations of river crayfishe within the lake has had a negative effect on the survival of the four Dojran endemic branchiobdelids. Other classes of Annelid include Oligochaeta, represented by 22 species, including the Dojran endemic species – Isochaeta dojranensis, and leeches (Hirudinea), represented by 10 species (Sotiria and Petkovski, 2004).
Arthropods (the phylum Arthropoda), including insects, arachnids, myriapods and crustaceans, is the most numerous taxonomic group within the Animal Kingdom.
Within crustaceans, recent investigations have determined that only nine of the original 25 water fleas (Cladocera) are still present in the lake, restricted to the pelagic complex of the zooplankton (Petkovski et al., 1999, 2001). Copepods, the class Copepoda, used to be represented by all three orders of freshwater copepods: Calanoida, Cyclopoida and Harpacticoida, with a total of 17 species, including the endemic species – Microcyclops varicans dojranensis (Petkovski 1954, 1983, 1991, 1999; Popovska Stankovic 1954, 1990, 2001; Griffiths et al. 2002). However, the more recent analysis indicates that copepods are now represented by only eight species (Petkovski et al., 2001, 2003). Ostracods, the classes Ostracoda, are represented by eight species. Klie (1941) described a new ostracod species from Lake Dojran – Physocypria inversa, which is considered to be Dojran endemic.
Petkovski (1958 and 1960) described two new ostracod subspecies from the benthic zone of Lake Dojran – Candona angulata meridionalis and Candona paionica. However, the endemic subspecies Candona paionica was not found in more recent studies (Saprakev et al. 1991; Ryan and Griffiths, 2001).
Higher crustaceans used to be abundant in the lake. The Order Amphipoda is represented by three species, and the species Orchestia cavicama and Gammarus roeselii triacanthus used to be abundant in the littoral zone of the lake at the depths of up to 3 m. Still, more recent investigations have shown that they appeared only sporadically (Petkovski et al. 1999, 2001; and Griffiths et al. 2002). The endemic Amphipoda – Niphargus pancici dojranensis – is not directly linked to the lake waters, but found in the spring area of the stream Deribash. Within crayfishes (the Order Decapoda), three species have been recorded in the lake; Atyaephyra desmaresti stankoi was abundant throughout the submersed vegetation of the littoral zone of the lake (reaching an abundance of up to 100 individuals/m2) prior to 1989 and the situation with the other two species is similar. Within insects, stoneflies (the Order Plecoptera) were presented by six species appearing in the streams that flow into Dojran (Ikonomov, 1983, 1986). The species Rhabdiopteryx doiranensis is a Dojran endemic, while Brachyptera macedonica is a national endemic. The subspecies Capnioneura balcanica macedonica, another national endemic, is also described from the same stream near Achikot. Booklice (the Order Psocoptera) is comprised of 16 recognized species (Gunther, 1980). The unique national endemic species of this taxonomic
group – Liposcelis macedonicus, is the Lake Dojran endemic, originally described from the vicinity of Achikot. Hadzisce (1953) mentioned the presence of three species of freshwater sponge, including the endemic Dojran sponge Spongilla carteri dojranensis, which has not been recorded in any other freshwater biotope. Living in the shallow littoral zone, which has experienced drastic changes in the late XX and early XXI century, this species has been seriously affected. However, it is estimated that it managed to adapt to the altered circumstances of the lake’s ecosystem.