Höhlentauchen / Cave Diving / Buceo en Cueva Riviera Maya
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DAN Divers Alert Network

DAN Divers Alert Network

DAN Divers Alert Network Training available with Diving CavesIn 2012 DAN has made a huge change and updated almost all of their courses. It is not an easy task to change all material, instructor guides, videos, promotional materials, so let’s give them the time to do in properly. Meanwhile I upgraded and renewed my credentials as DAN O2 instructor including the instructor for Advanced Oxygen and both courses with be merged together in the future and will be called

Emergency Oxygen for Scuba Diving Injuries

This course represents entry-level training to educate the general diving (and qualified non-diving) public to better recognize possible dive-related injuries and to provide emergency oxygen first aid while activating the local emergency medical services (EMS) and /or arranging for evacuation to the nearest available medical facility. Providers learn to use the demand inhalator valve, non-rebreather mask, manually triggered ventilator and a bag-valve mask (BVM).

So what is the difference to the old course? DAN included the use of the Bag-valve mask which is one of  the best tools for a layperson.

Why should you consider to become trained in Emergency Oxygen for Scuba Diving Injuries?

Imagine this set-up. You plan your dive vacation here. Let’s say you are a cave diver. The guide you booked with should have the first aid and oxygen kit always on the trip. So do you really know how it works? And seen it from the eyes of a technical diver, would you not want to be trained fit for the dive location you dive in? Caves are often somewhat remote to the highway, villages, hospitals. Do we have frequently accidents? Of course not, but in that one-in-a-million chance, I would like to be the best possible prepared to help a fellow diver in need and I would feel more comfortable if I know that my buddies have the same knowledge.

Merken

Black Vulture

Rabengeier, Black Vulture, Cave CenoteThe Black Vulture is a scavenger and feeds on carrion, but will also eat eggs or kill newborn animals. In areas populated by humans, it also feeds at garbage dumps. It is found in moist lowland forests and has therefore here an abundant distribution. It is usually seen soaring or perched on fence posts or dead trees. The Black Vulture lays its eggs on the ground in a wooded area, a hollow log, or some other cavity, seldom more than 3 metres above the ground.

It is known to regurgitate when approached or disturbed, which assists in predator deterrence and taking flight by decreasing its takeoff weight. Like all New World Vultures, the Black Vulture often defecates on its own legs, using the evaporation of the water in the feces and/or urine to cool itself, a process known as urohidrosis.

Vultures GeierThe Black Vulture appears in a variety of Maya hieroglyphics in Mayan codices. It is normally connected with either death or as a bird of prey. The vulture’s glyph is often shown attacking humans. This species lacks the religious connections that the King Vulture has. The mexican term for the black vulture, Zopilote, comes from nahuatl the language of the Aztecs (tzopilotl; “tzotl” means dirt and “pilotl” hang or carry referring to the way they carry the carrion while flying.

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Rootsicles

Rootsicles

rootsicle, versteinerte Wurzel ©Christine Loew
As our caves are quite shallow in many areas, roots very often extend into them in search of water. In areas where you have air spaces entrapped or air domes there is an ongoing calcification process of the roots that from so called rootsicles. As the fossilisation process continues and when the organic material has long since decayed, the calcite deposit preserve their shape and original form, we call these special kind of speleothems rhizomorph. These formation can grow to a considerable length and compared to the growth of stalactites also quicker.

Reference is made to an online Glossary of Caving Terms by Garry K Smith © (Aug.1998) which is very helpful to determine the correct word for some of the formations I get to see on my dives here.

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Merken

Calcite Rafts

Calcite Rafts

Calcite Rafts are formed when due to the oversaturation of the water with calcite it precipitates and clogs to these small rafts on the surface together. These rafts become after while too heavy to be supported anymore by osmotic tension and sink to the bottom and form a layered sediment deposition. The surfaces has to be protected from wind and stay unmoved for a long period of time so that the wonderful and very easily destroyable rafts can form. Therefore, you never will find them in the entrance areas of the cenotes, however, air domes of cave systems that are not that often dived, have still today surfaces covered with a thick calcite raft layer and in many tunnels you find them as deposition on the floor, which is an indication that for a long period of time this part of the caves was only partially flooded. Formations like these calcite rafts tell the story of the formations of the caves and are as precious and important to save as any other formation in the caves. A lack of current and other disturbing influence have preserved them over hundreds of thousands of years, so the diver should care at all times about a very good buoyancy, distance from the floor and excellent propulsion techniques during the dives.
calcite raft on the floor Kalzitflösse am Boden

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Blue Dancing Crab

Blue Dancing Crab

True crabs are distinguished from other so called crabs because they have a very short tail only which they sometimes also fold unter their body. The list of inhabitants of the Cenote logbook of the Riviera Maya names is as Blue Crab (Cardisoma guanhumi) a species  that lives only on land, however, based on fotographic comparisions and descriptions I identify this as Calllinectes sapidus, commonly known also as blue crab.

I call her dancing grab because this crustacean has a very territorial behaviour that is quite funny to look at. If you dive slowly closer, they start to wave the last pair of legs from left to right as if they hear some music. This pair of legs is flattened and normally used for swimming.

It is said that the blue crab is quite common on the golf of Mexico,  but the only place known to me so far is Casa Cenote close to Tulum.

FMAS

FMAS

When I returned from my holidays in May, I had a little slack time so when I got the invitation to participate in a crossover course to become a cave II instructor with FMAS (Federacion Mexicana de Actividades Subacuatica) held in Playa del Carmen on May, 23rd, 2012 in cenote Ponderosa. The preceding evening was for registration and information and in total 4 local cave instructors decided to cross over. Thank you to German Yanez and Bruno Espinosa for your great presentations.

The Cave II level o FMAS/CMAS is a bit more orientated for the technical cave diver requiring that the diver is Advanced Nitrox certified and on some dives stage tanks are required. An interesting second course I am now able to offer is the FMAS course for cavern and cave guiding.

Please ask for more information about the courses, detailed prerequisites etc.

Color Explosion

Color Explosion

When light is involved, the caves are stunningly colorful and gorgeous with all the little details

Connection to the Ocean

Connection to the Ocean

Casa Cenote is one of the cenotes that have a connection to the ocean and diveable. Life in this cenotes is completely different to other cenotes

Halocline

Halocline

Between two liquids of different densities, always an interface forms in between. Just imagine an oil and vinegar dressing. In the Yucatan aquifer, a similar interface permenantly exists between the fresh and saline waters and is called the halocline (from the APSA Cavern guide manual, section hydrogeology) as this is where there is a strong gradient of change in salt concentration. It is a wonderful experience being able to see and play with the halocline in some cenotes and caves! You can see it with your eyes because some of the beams from your light are refracted, or bounced off the halocline surface. This is also why halocline may look different from above and below as the angle of reflection is different depending whether you are looking from the fresh or saline water into the other.

Cenote Eden for example has a very striking halocline where the thickness is less than 1m, however, much thicker haloclines spanning many metres are common, for example in Mayan Blue’s B tunnel.

 

Blind Cave Fish

Blind Cave Fish

Olgibia pearsei

(Quote from Subterranean Fishes of the World, Graham S. Proudlove, page 177)

Habitat

Olgibia pearsei is the top predator in the Mayan Blue Cenote system and probably fulfils the same position in other locations (Pohlmann, Iliffe and Cifuentes, 1997; Pohlmann, Iliffe and Cifuentes, 2000). At least four species of troglobitic shrimps, Typhlatya mitchelli, T. campecheae, T. pearsei (Crustacea, Decapoda, Atyidae) and Creaseria morleyi (Crustacea, Decapoda,Palaemonidae) inhabit the subterranean waters of Yucatan (Hobbs and Hobbs, 1976; Holthuis, 1977) and these may form part of the food supply of the cave fishes. Reddell (1981) records other aquatic fauna from this area.