Cenote

A cenote ( Spanish; Mayathan ts'o'noot, in place names usually dzonot ) is a dolinenartiges limestone hole created by the collapse of a cave roof and filled with fresh water.

The term comes from the Maya of Mexico's Yucatán Peninsula. 954 cenotes are in the Mexican state of Quintana Roo known, a much smaller number in the neighboring state of Yucatán and Belize. They have an average depth of about 15 meters, separated by about 100 meters.

Genesis, properties and utilization

Cenotes (Spanish plural) occur in karst areas. The dissolution of the limestone to caves and underground watercourses form. Breaking a ceiling of these caves, so arise Tagöffnungen (English Aston Collapse ), which may extend to groundwater ( aquifer ). The Maya regarded them as inputs to the underworld ( xibalba ) and often used it as a religious sacrificial sites.

Many cenotes in Yucatán are probably the largest connected underwater cave system in the world combined. The two longest Systems, Ox Bel Ha ( 242 km) and Sac Actun (220 km), are accessible via more than 140 each cenotes. The total length of all the explored underwater cave systems in Quintana Roo is according to the current ( January 2013) knowledge of 1085 km.

It is believed that this cave systems, which are for the most part under water, was the reason for the development of the Mayan civilization, especially in the northwestern part of the Yucatán. The Maya used the cenotes as well, they served so that the water supply, which took place in almost all other civilizations by large above-ground rivers, like the Nile, Euphrates, Indus and Ganges. That is why some researchers call the cave system also known as " big power of the Maya ". Even in spite of prolonged droughts dense forest of Yucatán is attributed to the underground supply from the caves.

During the rainy season the water masses flowing into the aquifer. Freshwater deposits near the sea within the cave passages on the salt water, so that both above the other exists, but not mixed ( freshwater lens ). Within the caves leading to the formation of a thermocline, called the halocline. The depth of the halocline takes from a few meters near the sea continuously for up to about 30 meters inland. Mixing corrosion occurs in the region of the halocline to a broadening of the cavity cross section. The Cenotes form during the dry season in Yucatán often the only water points and accordingly are inhabited by a diverse wildlife.

Flora and Fauna

The banks of the Cenotenöffnungen are overgrown with marsh plants and lily family ( Nymphaeaceae ), the bare rock under water with krustierend growing red algae ( Rhodophyta ). Live on the banks of the subspecies Trachemys venusta terrapins venustra, almost constantly in the water, the biting Schlammschildkrötenart Kinosternon leucostomum. For the fish fauna of the cichlids Amphilophus robert soni, Rocio gemmata and Friedrich valley cichlid include ( Parachromis friedrichsthalii ), the endemic occur in the east of Yucatan, Paraneetroplus synspilus and Schwarzgebänderte cichlid ( Rocio octofasciata ). In addition, the blind Brotulaart Typhliasina pearsei, the Spitzmaulkärpfling ( Poecilia sphenops ), Poecilia mexicana, the Segelkärpfling ( Poecilia velifera ), the Zweifleckkärpfling ( Pseudoxiphophorus bimaculatus ), the Schläfergrundel Gobiomorus dormitor, the Guatemala catfish ( Rhamdia Quelen ) and the Salmlerarten Astyanax aeneus, Astyanax fasciatus and Astyanax mexicanus. From the latter, the cenotes are populated by the " normal form ", while the known as a blind Höhlensalmler blind cave form is only found in three caves in the central Mexican state of San Luis Potosí.

Chicxulub crater

In the northwest of the Yucatán aquifer and thus the caves caused by the impact of the Chicxulub meteorite fractures and dislocations follow. The associated semi-circular ring of cenotes forms the otherwise long -buried crater rim after even today.