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Posted by Cenote Xplore on 10/07/2018
Posted by Cenote Xplore on 11/12/2017
Successfully completed the course Introductory Cave Diver
Congratulations to Lyudmila A. (Russia) with the course IANTD Introductory Cave Diver. Seven strenuous days, 18 training dives. Instructor on the course Andrew Stanishevski, assistant Maria Shagina. We wish Ludmila safe and exciting dives.
Posted by Cenote Xplore on 07/09/2017
In many coastal caves there is a fresh layer on top of a dense layer of salt water. One could expect mixing of salt and fresh water in a cave and the formation of a layer of water of medium salinity. Instead, imagine the relationship between salt and fresh water as an oil-water relationship – they never mix because of different densities.
In most cases, the so-called halocline is formed at the junction. The glycolin usually has clear boundaries (a few centimeters in width), but it can be more blurred and spread over several meters. Cave divers can see the boundary of the halocline because of the refraction of light due to the different density of water. It can look like a mirror surface, a false bottom or a surface of water, and when you touch the halocline begins to blur. The unique chemical composition of this layer of water is discussed in more detail in subsequent publications.
With the help of reconnaissance, accurate geodesy and cartography, cave divers have brought many new knowledge to the scientific community. Without this information, it would be much more difficult to model the flow regimes for better understanding them. Cave divers can help hydrological research by measuring the speed of water flow, and help to investigate the quality of groundwater, noting the color of water, temperature, depth of the halocline, and making water sampling.
Posted by Cenote Xplore on 12/08/2017
Breathing and circulation
Posted by Cenote Xplore on 15/06/2017
Posted by Cenote Xplore on 23/04/2017
Posted by Cenote Xplore on 26/03/2017
Posted by Cenote Xplore on 20/03/2017
Causes of poor visibility in cave diving
Bad visibility and cloudiness in the cave can be caused by various factors, such as the size of sediments and mud, irregular or sloppy fins, the rainy season or floods. The larger and heavier the deposit is, the faster it settles on the bottom of the cave. The easier and smaller the deposits are, the more time it takes to fully subsidence and restore visibility.
Sand, clay, mud, sludge, sediments and decomposed organics make up most of the layer covering the floor of the cave. Also, bacteria can grow in the caves. One wrong move can easily lead to a complete drop in visibility within seconds.
Diver faces the danger of raising sediments, using the wrong swimming technique, dragging the equipment along the floor of the cave, touching the floor or walls, or knocking off the deposits from the ceiling with bubbles. Sometimes all this happens simultaneously.
Also, some chemical compounds, for example, hydrogen sulphide, can be found in the caves, which usually looks like a white cloud of varying density, smells of rotten eggs, and at high concentrations can cause dizziness in a diver. Tannin of soil color, washed away into the cave by rain, has the same visibility characteristics as tea or coffee. Haloclines are formed in places where fresh and salt water are mixed. The visibility in the halocline layer is usually zero, the diver sees only the blurred outlines through the mask.
Cave systems are underground rivers with their currents. If the current is strong enough, the diver will feel the resistance of the water at the entrance to the cave. Sometimes, if a turbidity has come up at the entrance, the diver can make a choice in favor of waiting until the current clears the suspension, guided by the rules for calculating gas. In caves where there is no current, the silt layer will be thicker, and in case of cloudiness the cloud of deposits will settle for longer. In such caves you should not wait until visibility is restored with the help of the current.