The Ayalon Cave (,

Arabic Arabic (, , or , ) is a Central Semitic languages, Central Semitic language of the Afroasiatic languages, Afroasiatic language family spoken primarily in the Arab world. The International Organization for Standardization (ISO) assigns lang ...

Aramaic Aramaic (; ) is a Northwest Semitic language that originated in the ancient region of Syria and quickly spread to Mesopotamia, the southern Levant, Sinai, southeastern Anatolia, and Eastern Arabia, where it has been continually written a ...

, Shiha شيحا) is a large limestone cave near

Ramla Ramla (), also known as Ramle (, ), is a city in the Central District of Israel. Ramle is one of Israel's mixed cities, with significant numbers of both Jews and Arabs. The city was founded in the early 8th century CE by the Umayyad caliph S ...

Israel Israel, officially the State of Israel, is a country in West Asia. It Borders of Israel, shares borders with Lebanon to the north, Syria to the north-east, Jordan to the east, Egypt to the south-west, and the Mediterranean Sea to the west. Isr ...

, with a worldwide unique ecosystem. As

photosynthesis Photosynthesis ( ) is a system of biological processes by which photosynthetic organisms, such as most plants, algae, and cyanobacteria, convert light energy, typically from sunlight, into the chemical energy necessary to fuel their metabo ...

is not possible inside the completely dark cave, the

food chain A food chain is a linear network of links in a food web, often starting with an autotroph (such as grass or algae), also called a producer, and typically ending at an apex predator (such as grizzly bears or killer whales), detritivore (such as ...

that developed inside is solely based on bacteria capable of

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, hydrog ...

: the bacteria are consuming the inorganic matter available in the groundwater, and then themselves become the organic food source for the rest of the food chain. As of 2021, Ayalon Cave was one of less than 10 such subterranean ecosystems known in the world, with each of them being distinctly different from the rest. Eight new invertebrate species were discovered there in April 2006 - four seawater and freshwater

crustaceans Crustaceans (from Latin meaning: "those with shells" or "crusted ones") are invertebrate animals that constitute one group of Arthropod, arthropods that are traditionally a part of the subphylum Crustacea (), a large, diverse group of mainly aquat ...

along with four terrestrial animals, one of them a species of blind

scorpion Scorpions are predatory arachnids of the Order (biology), order Scorpiones. They have eight legs and are easily recognized by a pair of Chela (organ), grasping pincers and a narrow, segmented tail, often carried in a characteristic forward cur ...

– with many more expected to be discovered.

Discovery and description

According to historian

Roy Marom Roy Marom (, ) is an Israeli historian and historical geographer. Marom is the curator of the Palestinian Rural History Project, which specializes in the history of the Palestinian countryside during the Ottoman and British Mandate periods. ...

, the existence of significant caves on the site was known to the ancients. In the 16th century, the site is recorded as Mazraʽat šīḥah /Mazraʽat šīḥa/ 4 “the farm of the pit, cavity, ditch”, from Aramaic šyḥ’, exemplifiying and motivated by the fact that the site has dozens of caves and underground caverns. In the 19th century, the site was known as muġur šīḥa ("Shiha Caves"). The cave was rediscovered in 2006 when a small opening was discerned in the quarry. The cave, deep, extends including its branches, which makes it the third-largest limestone cave in Israel.

Significance

According to Professor Amos Frumkin of the

Hebrew University The Hebrew University of Jerusalem (HUJI; ) is an Israeli public research university based in Jerusalem. Co-founded by Albert Einstein and Chaim Weizmann in July 1918, the public university officially opened on 1 April 1925. It is the second-ol ...

, the cave is unique in that a thick layer of

limestone Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...

left it impermeable to any water coming from the surface. It has been studied for its complex

food web A food web is the natural interconnection of food chains and a graphical representation of what-eats-what in an ecological community. Position in the food web, or trophic level, is used in ecology to broadly classify organisms as autotrophs or he ...

, which survived for millions of years without light or organic food coming in from the surface, being based solely on a type of bacterium which feeds on sulfur which serves as the only organic matter available for the next higher level of organisms to feed on. The cave has offered an ecological refuge for species whose relatives living at the surface have been wiped out by climatic changes and catastrophic events over millions of years, and offers a unique sample for the study of long-term ecological changes in the area.

Ecosystem

Photosynthesis-free food chain

As the cave was completely cut off from the outside environment, it sustained an independent

ecosystem An ecosystem (or ecological system) is a system formed by Organism, organisms in interaction with their Biophysical environment, environment. The Biotic material, biotic and abiotic components are linked together through nutrient cycles and en ...

; this ecosystem relied for an

energy Energy () is the physical quantity, quantitative physical property, property that is transferred to a physical body, body or to a physical system, recognizable in the performance of Work (thermodynamics), work and in the form of heat and l ...

source neither on

sunlight Sunlight is the portion of the electromagnetic radiation which is emitted by the Sun (i.e. solar radiation) and received by the Earth, in particular the visible spectrum, visible light perceptible to the human eye as well as invisible infrare ...

and

, nor on an external source of

organic compounds Some chemical authorities define an organic compound as a chemical compound that contains a carbon–hydrogen or carbon–carbon bond; others consider an organic compound to be any chemical compound that contains carbon. For example, carbon-co ...

. Rather, energy was extracted by

chemoautotrophic A chemotroph is an organism that obtains energy by the oxidation of electron donors in their environments. These molecules can be organic (chemoorganotrophs) or inorganic (chemolithotrophs). The chemotroph designation is in contrast to phototroph ...

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

, living in a film on top of the water of an underground lake. These bacteria produce energy by

oxidizing Redox ( , , reduction–oxidation or oxidation–reduction) is a type of chemical reaction in which the oxidation states of the reactants change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is ...

the

sulfide Sulfide (also sulphide in British English) is an inorganic anion of sulfur with the chemical formula S2− or a compound containing one or more S2− ions. Solutions of sulfide salts are corrosive. ''Sulfide'' also refers to large families o ...

compounds in the water, and derive organic compounds using

carbon dioxide Carbon dioxide is a chemical compound with the chemical formula . It is made up of molecules that each have one carbon atom covalent bond, covalently double bonded to two oxygen atoms. It is found in a gas state at room temperature and at norma ...

from the air. These compounds form the basis of the cave's ecosystem. The temperature and salt content of the cave's water indicates that it originates from sources deep underground. Although this cave is part of an

aquifer An aquifer is an underground layer of water-bearing material, consisting of permeability (Earth sciences), permeable or fractured rock, or of unconsolidated materials (gravel, sand, or silt). Aquifers vary greatly in their characteristics. The s ...

fed by rain falling in the mountains to the east, which happens to be one of the main potable water sources for

and the

Palestinian territories The occupied Palestinian territories, also referred to as the Palestinian territories, consist of the West Bank (including East Jerusalem) and the Gaza Strip—two regions of the former Mandate for Palestine, British Mandate for Palestine ...

, chemically more complex sources can create local pockets with very specific water composition.

New species

Researchers announced that they had discovered eight species previously unknown to science, all without eyes, comprising four aquatic

crustacean Crustaceans (from Latin meaning: "those with shells" or "crusted ones") are invertebrate animals that constitute one group of arthropods that are traditionally a part of the subphylum Crustacea (), a large, diverse group of mainly aquatic arthrop ...

species and four other species of terrestrial crustaceans and

springtail Springtails (class Collembola) form the largest of the three lineages of modern Hexapoda, hexapods that are no longer considered insects. Although the three lineages are sometimes grouped together in a class called Entognatha because they have in ...

s. A species of eyeless

troglobitic A troglobite (or, formally, troglobiont) is an animal species, or population of a species, strictly bound to underground habitats, such as caves. These are separate from species that mainly live in above-ground habitats but are also able to live u ...

scorpion representing an unknown taxonomic family was discovered only a decade or so after its extinction. This was probably caused by overpumping of the

ground water Groundwater is the water present beneath Earth's surface in rock and soil pore spaces and in the fractures of rock formations. About 30 percent of all readily available fresh water in the world is groundwater. A unit of rock or an unconsolidat ...

, which has led the underground lake to shrink, and with it the food supply to dwindle. The ten specimen found dead in the cave are exceptionally well preserved and allowed the conclusion that they used a motion detecting organ situated on their abdomen for orientation. The species was given the name '' Akrav israchanani'', from the

Hebrew Hebrew (; ''ʿÎbrit'') is a Northwest Semitic languages, Northwest Semitic language within the Afroasiatic languages, Afroasiatic language family. A regional dialect of the Canaanite languages, it was natively spoken by the Israelites and ...

word for scorpion, "akrav", and honouring the researchers who identified it, Israel Naaman and Hanan Dimentman.

2021 destruction threat averted

The cave is located on the premises of a limestone quarry owned by the cement manufacturing Nesher Industries. As of 2021, a new railway line required that the Ayalon River valley be narrowed, and the National Infrastructure Committee together with the

Water Authority A water board is a regional or national organisation that has very different functions from one country to another. The functions range from flood control and water resources management at the regional or local level (the Netherlands, Germany), ...

were planning to divert runoff water in winter so as to avoid flooding by the Ayalon River, the quarry with the Ayalon Cave having been proposed as a possible catchment pool. Various scientists and the

Israel Nature and Parks Authority The Israel Nature and Parks Authority (, ; ) is an Israeli government organization that manages nature reserves and national parks in Israel, the Golan Heights and parts of the West Bank. The organization was founded in April 1998, merging two o ...

have been opposed to the idea, with an online public signature collection supporting their position. Scientists argued that a massive influx of surface runoff water, which is totally different from the groundwater on which the unique cave ecosystem is based, would be sure to destroy it. The intervention by Israeli and foreign researchers and the public petition has saved the cave's ecosystem, the authorities deciding for a different technical solution.

Access

The cave is not accessible to the public. Only a small number of researchers are allowed to enter.

References

External links

National Geographic
* {{Caves in Israel Caves of Israel Limestone caves Ramla