Editing Cenote (section)

===Freshwater/seawater interface===
The Yucatán Peninsula contains a vast coastal [[aquifer]] system, which is typically density-stratified.<ref name="Beddows, P.A. 2003"/> The infiltrating [[meteoric water]] (i.e., rainwater) floats on top of higher-[[density]] [[saline water]] intruding from the coastal margins. The whole aquifer is therefore an [[Anchialine pool|anchialine system]] (one that is land-locked but connected to an ocean). Where a cenote, or the flooded cave to which it is an opening, provides deep enough access into the aquifer, the interface between the fresh and saline water may be reached. The density interface between the fresh and saline waters is a [[halocline]], which means a sharp change in salt concentration over a small change in depth. Mixing of the fresh and saline water results in a blurry swirling effect caused by [[refraction]] between the different densities of fresh and saline waters.

The depth of the halocline is a function of several factors: climate and specifically how much meteoric water recharges the aquifer, [[hydraulic conductivity]] of the host rock, distribution and connectivity of existing cave systems, and how effective these are at draining water to the coast, and the distance from the coast. In general, the halocline is deeper further from the coast, and in the Yucatán Peninsula this depth is {{convert|10|to|20|m|abbr=on}} below the [[water table]] at the coast, and {{convert|50|to|100|m|abbr=on}} below the water table in the middle of the peninsula, with saline water underlying the whole of the peninsula.<ref name="Beddows, P.A. 2003"/>
[[File:Cenote IK KIL map.png|alt=cutaway of cenote ik kil, at the bottom there is a pile of debris|thumb|upright=1.25|Geological cutaway of [[Ik Kil|Cenote Ik Kil]]]]