Movile Cave () is a cave near

Mangalia Mangalia (, tr, Mankalya), ancient Callatis ( el, Κάλλατις/Καλλατίς; other historical names: Pangalia, Panglicara, Tomisovara), is a city and a port on the coast of the Black Sea in the south-east of Constanța County, Northern D ...

Constanța County Constanța () is a county ( județ) of Romania on the border with Bulgaria, in the Dobruja region. Its capital city is also named Constanța. Demographics In 2011, it had a population of 684,082 and the population density was 96/km2. The deg ...

Romania Romania ( ; ro, România ) is a country located at the crossroads of Central Europe, Central, Eastern Europe, Eastern, and Southeast Europe, Southeastern Europe. It borders Bulgaria to the south, Ukraine to the north, Hungary to the west, S ...

discovered in 1986 by Cristian Lascu a few kilometers from the

Black Sea The Black Sea is a marginal mediterranean sea of the Atlantic Ocean lying between Europe and Asia, east of the Balkans, south of the East European Plain, west of the Caucasus, and north of Anatolia. It is bounded by Bulgaria, Georgia, Roma ...

coast. It is notable for its unique groundwater ecosystem abundant in

hydrogen sulfide Hydrogen sulfide is a chemical compound with the formula . It is a colorless chalcogen-hydride gas, and is poisonous, corrosive, and flammable, with trace amounts in ambient atmosphere having a characteristic foul odor of rotten eggs. The unde ...

and

carbon dioxide Carbon dioxide (chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is transpar ...

, but low in

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 wel ...

. Life in the cave has been separated from the outside for the past 5.5 million years and it is based completely on

chemosynthesis In biochemistry, chemosynthesis is the biological conversion of one or more carbon-containing molecules (usually carbon dioxide or methane) and nutrients into organic matter using the oxidation of inorganic compounds (e.g., hydrogen gas, hydro ...

rather than

photosynthesis Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities. Some of this chemical energy is stored i ...

. Similar caves where life partly or fully depends on chemosynthesis have been found in Ein-Nur Cave and

Ayalon Cave The Ayyalon Cave ( he, מערת איילון) is a large limestone cave near Ramla, Israel in which new species of crustaceans were discovered in April 2006. It has been studied for its complex food web, which survived for millions of years with ...

(Israel),

Frasassi Caves The Frasassi Caves (Italian: ''Grotte di Frasassi'') are a karst cave system in the municipality of Genga, Italy, in the province of Ancona, Marche. They are among the most famous show caves in Italy. History The caves, discovered by a group ...

(Italy), Melissotrypa Cave (Greece), Tashan Cave (Iran), caves in the Sharo-Argun Valley in the

Caucasus Mountains The Caucasus Mountains, : pronounced * hy, Կովկասյան լեռներ, : pronounced * az, Qafqaz dağları, pronounced * rus, Кавка́зские го́ры, Kavkázskiye góry, kɐfˈkasːkʲɪje ˈɡorɨ * tr, Kafkas Dağla ...

, Lower Kane Cave and Cesspool Cave (USA), and Villa Luz Cave (Mexico).

Chemical environment

The air in the cave is very different from the outer atmosphere. The level of oxygen is only a third to half of the concentration found in open air (7–10% O₂ in the cave atmosphere, compared to 21% O₂ in air), and about one hundred times more carbon dioxide (2–3.5% CO₂ in the cave atmosphere, versus 0.04% CO₂ in air). It also contains 1–2%

methane Methane ( , ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The relative abundance of methane on Eart ...

(CH₄) and both the air and waters of the cave contain high concentrations of

(H₂S) and

ammonia Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous was ...

(NH₃). The water in the lake only contains some dissolved oxygen the first centimeter at most, and some places only the first millimeter. Deeper down, and it becomes completely anoxic.

Biology

The cave is known to contain 57 animal species,GESS Lab. (2020). Movile Cave - a unique ecosystem. Gesslab. https://www.gesslab.org/movile-caveGESS Lab. (2020a). List of invertebrate species encountered and described in the Movile Cave ecosystem. https://fecc112f-3776-4476-a602-1572b7478186.filesusr.com/ugd/1e4de5_ebb50699a75848bbb0c3f12a65da4c5d.pdf among them

leech Leeches are segmented parasitic or predatory worms that comprise the subclass Hirudinea within the phylum Annelida. They are closely related to the oligochaetes, which include the earthworm, and like them have soft, muscular segmented bodie ...

es,

spider Spiders ( order Araneae) are air-breathing arthropods that have eight legs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude silk. They are the largest order of arachnids and rank seventh in total species ...

pseudoscorpion Pseudoscorpions, also known as false scorpions or book scorpions, are small, scorpion-like arachnids belonging to the order Pseudoscorpiones, also known as Pseudoscorpionida or Chelonethida. Pseudoscorpions are generally beneficial to humans sin ...

woodlice A woodlouse (plural woodlice) is an isopod crustacean from the polyphyleticThe current consensus is that Oniscidea is actually triphyletic suborder Oniscidea within the order Isopoda. They get their name from often being found in old wood. ...

, a

centipede Centipedes (from New Latin , "hundred", and Latin , " foot") are predatory arthropods belonging to the class Chilopoda (Ancient Greek , ''kheilos'', lip, and New Latin suffix , "foot", describing the forcipules) of the subphylum Myriapoda, an ...

,Varpu Vahtera, Pavel Stoev, Nesrine Akkari
Five million years in the darkness: A new troglomorphic species of ''Cryptops'' Leach, 1814 (Chilopoda, Scolopendromorpha) from Movile Cave, Romania
On: ZooKeys 1004: pp 1-26. doi:10.3897/zookeys.1004.58537 (16 December 2020). See also: * David Nield
Meet The 'King' of a Toxic Underground Ecosystem Unlike Anywhere Else on Earth
On: science^alert. 19 December 2020. About ''

Cryptops speleorex ''Cryptops'' sometimes known as cave centipedes, is a centipede genus in the family Cryptopidae; species records have a world-wide distribution. Species The Global Biodiversity Information Facility includes: *'' Cryptops vector'' Chamberlin, 1 ...

'', the cave dwelling sister species of '' C. hortensis'', Cryptopidae
New Centipede Discovered on Top of Food Chain in Hellish Ecosystem of a Sulfur-Soaked Romanian Cave
On: SciTechDaily. December 16, 2020 a

water scorpion Nepidae is a family of exclusively aquatic Heteropteran insects in the order Hemiptera. They are commonly called water scorpions for their superficial resemblance to scorpions, due to their raptorial forelegs and the presence of a long slender p ...

(''

Nepa anophthalma The National Environmental Policy Act (NEPA) is a United States environmental law that promotes the enhancement of the environment and established the President's Council on Environmental Quality (CEQ). The law was enacted on January 1, 1970.Un ...

''), and also a snail. Of these, 37 are

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

. The

food chain A food chain is a linear network of links in a food web starting from producer organisms (such as grass or algae which produce their own food via photosynthesis) and ending at an apex predator species (like grizzly bears or killer whales), det ...

is based on

by methane- and sulfur-oxidizing bacteria, which in turn release nutrients for

fungi A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from ...

and other

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...

. This forms

microbial mat A microbial mat is a multi-layered sheet of microorganisms, mainly bacteria and archaea, or bacteria alone. Microbial mats grow at interfaces between different types of material, mostly on submerged or moist surfaces, but a few survive in deserts. ...

s on the cave walls and the surface of lakes and ponds which are grazed on by some of the animals. The grazers are then preyed on by predatory species. ''

Nepa The National Environmental Policy Act (NEPA) is a United States environmental law that promotes the enhancement of the environment and established the President's Council on Environmental Quality (CEQ). The law was enacted on January 1, 1970.Un ...

anophthalma'' is the only known cave-adapted water scorpion in the world. While animals have lived in the cave for 5.5 million years, not all of them arrived simultaneously. One of the most recent animals recorded is the cave's only species of snail, '' Heleobia dobrogica'', which has inhabited the cave for slightly more than 2 million years.Andrzej Falniowski, Magdalena Szarowska, Ioan Sirbu, Alexandra Hillebrand, Mihai Baciu
''Heleobia dobrogica'' (Grossu & Negrea, 1989)(Gastropoda: Rissooidea: Cochliopidae) and the estimated time of its isolation in a continental analogue of hydrothermal vents
In: Molluscan Research 28(3): pp 165-170. 22 Dec 2008. ISSN 1323-5818

References

General references

* Jean Balthazar: ''Grenzen unseres Wissens.'' Orbis Verlag, München 2003, Seite 268, . * *

Inline citations

{{Reflist

External links

The Movile Cave Project at web.archive.org

(fr.)

Life in Hell – Survivors of Darkness. Mona Lisa Production, France
Caves of Romania Geography of Constanța County Ecosystems Endemism