Cueva de Villa Luz, an extremely interesting cave in Tabasco, Mexico, has piqued my interest in light of a short segment of Planet Earth that we watched in our Limnology class today. Before today I had never heard of this cave before. In actuality I had never heard of anything like the biology and ecology of this cave and the way it works. The water flowing through this cave is acidified by sulfuric acid produced by many different kinds of bacteria that form “snottites” throughout the cave.
After hearing the term “snottite,” I was very curious as to what type of bacteria could be forming these sulfuric acid producing snot-like things hanging from the ceiling of the cave. The snottites are stalactites made out of bacterial goo. Hydrogen sulfide, a very poisonous gas leaked up through oil deposits deep in the bottom of the cave, is utilized by these bacteria as an energy source. These bacteria produce the sulfuric acid as a waste product. (The types of bacteria that are found in these snottites are part of a group called the Eubacteria.)
The sulfuric acid then drips down from the snottites into the water below them which in turn acidifies the water. Because of the acid being leaked into the water, the cave is generally more acidic than most other cave environments.
So, besides acidifying the water flowing through the cave, what other uses do the snottites have? The snottites provide a food source for many fish and other insects that live in the cave. One insect in particular that uses the snottites as a food source is the midge that lives in the cave. The midges lay their eggs on the snottites so that the larva can use the bacteria as their main food source.
The acid produced by the snottites also helps to shape and reshape the cave, producing more habitat and changing the form of the cave bottom. So in looking at the bacteria in the snottites, there have been many discoveries about the functionality of these complex bacterial interactions with not only the rock but also with the organisms living in the cave.
http://caveslime.org/VillaLuz/
http://findarticles.com/p/articles/mi_m1590/is_n1_v55/ai_21169671/?tag=content;col1
