Cave Caves Essay

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Introduction
Caves are natural, underground cavities formed by chemical dissolution of the bedrock or other geological processes. Based on the geological process responsible for their formation, caves can be divided into karstic and pseudokarstic (sensu Klimchouk 2004). Karstic caves derived from dissolution of the bedrock, whereas pseudokarstic are formed by other processes such as erosion by water and tectonic forces (sensu Klimchouk 2004). Although caves can be formed through different geological processes in different types of parent rock, the majority of natural caves worldwide are formed by dissolution of the bedrock (Klimchouk 2004); caves derived from this process are also known as solutional or karstic caves.
The term ‘karst’ refers …show more content…

Moore (1952) introduced the term ‘speleothem’ in order to describe the different types of secondary mineral deposits (i.e. decoration). Taking a step forward, Hill and Forti (1985) divided speleothems into four categories: dripstone (e.g. stalactites, stalagmites, ‘curtains’), flowstone (e.g. stone waterfalls), pore deposits (e.g. helictites) and pool deposits (e.g. ‘cave pearls’). Overall, all types of speleothems are formed by water saturated with dissolved calcite (CaCO3). As it is already mentioned, rainwater passes through the soil, absorbs carbon dioxide, and becomes slightly acidic. Through this process, acidic water also becomes saturated with calcite and, as this solution enters the cave, carbon dioxide is released; therefore, a supersaturated solution is created. As a result, calcite is deposited, leading thus, to the formation and development of speleothems (Dreybrodt 2012). However, the growth of speleothems is influenced not only by abiogenic processes; the contribution of microbes to the development of speleothems is nowadays confirmed by several researchers (e.g. Northup and Lavoie 2001, Barton and Jurado 2007, Cuezva et al. 2009, Bindschedler et al. 2014, Shtober-Zisu et al. 2014). As an example, a combination of both biogenic (i.e. caused by microbial activity) and abiogenic processes contributes to the formation of moonmilk, a soft and spongy type of speleothem commonly found in several caves …show more content…

The ‘entrance’ zone is climatically variable and is affected by the environmental conditions prevailing in the immediate outside environment of the cave whereas the ‘dim light’ zone (innermost part of the cave) is characterized by dim or no light; also, temperature is relatively stable through the year and relative humidity levels reaches the maximum values recorded in the cave. Another zone located between the entrance and the dim light zone (i.e. ‘transition’ zone) exhibits characteristics of either the entrance or the dim light zone (Christodoulou et al. 2015). Photosynthetic microorganisms are able to use light at various wavelengths between 400 -700 nm for primary production; it can be thus concluded that the progressive reduction of natural light controls the growth of photosynthetic microflora (Pantazidou 1996, Ascencio and Aboal 2000, Beltran and Ascencio 2009, Lamprinou et al. 2009, Roldan and Hernandez-Marine 2009, Christodoulou et al. 2011, Albertano

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