Lake Hévíz is located in

Hévíz Hévíz is a spa town in Zala County, Hungary, about from Keszthely. Description of the lake The town is located near Lake Hévíz, the world’s second-largest thermal lake, but biologically the biggest active natural lake. Its temperatur ...

Hungary Hungary ( hu, Magyarország ) is a landlocked country in Central Europe. Spanning of the Pannonian Basin, Carpathian Basin, it is bordered by Slovakia to the north, Ukraine to the northeast, Romania to the east and southeast, Serbia to the ...

, near the western end of

Lake Balaton Lake Balaton () is a freshwater lake in the Transdanubian region of Hungary. It is the largest lake in Central Europe, and one of the region's foremost tourist destinations. The Zala River provides the largest inflow of water to the lake, and ...

, from

Keszthely Keszthely (; also known by other alternative names) is a Hungarian city of 20,895 inhabitants located on the western shore of Lake Balaton. It is the second largest city by the lake and one of the more important cultural, educational and economi ...

. It is the largest swimmable

thermal lake A hot spring, hydrothermal spring, or geothermal spring is a spring produced by the emergence of geothermally heated groundwater onto the surface of the Earth. The groundwater is heated either by shallow bodies of magma (molten rock) or by circ ...

in the world ( in area), second only to Frying Pan Lake in New Zealand, which is too hot for swimming. The flow of water is very strong and the water in the lake is completely replenished every 72 hours. Its minimum depth is 2 meters, reaching a maximum depth of 38 meters, exactly at the point where the hot thermal water comes out to the surface.

Microscopic organisms of the lake

The

fauna Fauna is all of the animal life present in a particular region or time. The corresponding term for plants is ''flora'', and for fungi, it is ''funga''. Flora, fauna, funga and other forms of life are collectively referred to as ''Biota (ecology ...

and

flora Flora is all the plant life present in a particular region or time, generally the naturally occurring (indigenous (ecology), indigenous) native plant, native plants. Sometimes bacteria and fungi are also referred to as flora, as in the terms '' ...

are unique in Lake Hévíz due to the

temperature Temperature is a physical quantity that expresses quantitatively the perceptions of hotness and coldness. Temperature is measurement, measured with a thermometer. Thermometers are calibrated in various Conversion of units of temperature, temp ...

and chemical composition of the water, which contains carbonic acid, calcium, magnesium, hydrogen carbonate, reduced sulfuric compounds as well as

oxygen Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as ...

in solution. Several

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

so far can be found only in this lake.

Bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of prokaryotic microorganisms. Typically a few micrometr ...

is the dominant

life form Life form (also spelled life-form or lifeform) is an wikt:entity, entity that is Life, living, such as plants (flora) and animals (fauna). It is estimated that more than 99% of all species that ever existed on Earth, amounting to over five billi ...

in the lake; it is possible that this is a cause of the curative effect. Several

taxa In biology, a taxon (back-formation from ''taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular nam ...

can be found here. Most common Cyanobacteria are filamentous blue-green

alga Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mic ...

e (''Oscillatoria princeps'', ''O. tenuis'', ''O. jasoruensis'', ''O. chlorina'', '' Spirulina major''). Half of the blue species are

thermophile A thermophile is an organism—a type of extremophile—that thrives at relatively high temperatures, between . Many thermophiles are archaea, though they can be bacteria or fungi. Thermophilic eubacteria are suggested to have been among the earl ...

, stenoterm ones. There are two thermophile blue green alga species (''Pseudanabaena papillaterminata'', ''Pseudanabaena crassa'') of which Lake Hévíz is the only Hungarian habitat. Bacterial tektons are typical of the lake. The crater is covered mostly by ''

Thiothrix ''Thiothrix'' is a genus of filamentous sulfur-oxidizing bacteria, related to the genera '' Beggiatoa'' and ''Thioploca''. They are usually Gram-negative (but can be Gram-variable) and rod-shaped (0.7–1.5 µm in width by 1.2–2.5 µm ...

'' sp. and '' Beggiatoa'' sp. from a depth of 1.5 m to the opening of the springcave. These together with the bacterium species play an important role in the lake's sulfur cycle.

Actinomycete The Actinomycetales is an order of Actinomycetota. A member of the order is often called an actinomycete. Actinomycetales are generally gram-positive and anaerobic and have mycelia in a filamentous and branching growth pattern. Some actinomycete ...

s ('' Streptomyces'' sp., ''

Micromonospora ''Micromonospora'' is a genus of bacteria of the family Micromonosporaceae. They are gram-positive, spore-forming, generally aerobic, and form a branched mycelium; they occur as saprotrophic forms in soil and water. Various species are sources ...

'' sp.) are also worth mentioning. '' Micromonospora heviziensis'' for instance, a very powerful protein and cellulose decomposer, can only be found here in the world. Microbispora amethystogenes on the other hand, which accumulates iodine in its cells, is to be found in only few lakes in the world. Unfortunately this latter species has not been found in the lake since the 1980s as a result of excessive

mining Mining is the extraction of valuable minerals or other geological materials from the Earth, usually from an ore body, lode, vein, seam, reef, or placer deposit. The exploitation of these deposits for raw material is based on the economic ...

. Changing environment affected other bacteria as well. ''Micromonospora carbonacea'' and ''M. chalcea'' was not detected in the 1990s. Actinomycetes communities have become dominated by ''Micromonospora purpureochromogenes'', while ''M. heviziensis'' was suppressed. Antibiotics secreting ''Streptomyces'' are likely to be found. GyógyfürdőHévíz

Green algae – especially ''

Chlorella ''Chlorella'' is a genus of about thirteen species of single-celled green algae belonging to the division Chlorophyta. The cells are spherical in shape, about 2 to 10 μm in diameter, and are without flagella. Their chloroplasts contain the ...

'' sp. – are present all over the lake except for the springcave and its surroundings. '' Navicula cryptocephala'' and '' Navicula capitatoradiata ''are common diatoms in the lake. The biodiversity of the phytoplankton is poor and its biomass is low, thus the lake's

trophic level The trophic level of an organism is the position it occupies in a food web. A food chain is a succession of organisms that eat other organisms and may, in turn, be eaten themselves. The trophic level of an organism is the number of steps it ...

ranges from oligotrophic to mesotrophic. There are two new species of

Nematoda The nematodes ( or grc-gre, Νηματώδη; la, Nematoda) or roundworms constitute the phylum Nematoda (also called Nemathelminthes), with plant-parasitic nematodes also known as eelworms. They are a diverse animal phylum inhabiting a broa ...

: '' Crocodolrylaimus thermalis'' and '' Neoactinolaimus tepidus''. There can be found real rarities among Rotatorias as well ('' Epiphanes brachionus'' var. ''Spinosus'', '' Lecane inermis''), which are only present in warm waters. Jenő Ponyi has described the lake's primitive

crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group can ...

s in detail. Also a unique ''

Hydracarina Hydrachnidia, also known as "water mites", Hydrachnidiae, Hydracarina or Hydrachnellae, are among the most abundant and diverse groups of Benthic zone, benthic arthropods, composed of 6,000 described species from 57 families. As water mites of ...

acarus ''Acarus'' is a genus of mites in the family Acaridae. Species * '' Acarus ananas'' (Tryon, 1898) * '' Acarus beschkovi'' (Mitov, 1994) * '' Acarus bomiensis'' Wang, 1982 * '' Acarus calcarabellus'' (Griffiths, 1965) * '' Acarus chaetoxysilos'' ...

'' is said to have found its habitat outside the fence surrounding the lake.

Medicinal properties

The waters are reported to be beneficial to patients with rheumatic diseases and locomotor disorders, among others. There is a thriving health tourism industry in the area.

References

External links

nature conservation areas of Balaton Uplands National Park

Heviz

{{DEFAULTSORT:Lake Heviz Heviz Geography of Zala County Hot springs of Hungary Heviz Tourist attractions in Zala County Volcanoes of Hungary

Microscopic organisms of the lake

Medicinal properties

See also

References

External links