Living in the Rainforest: Karst and Caves

One third of Puerto Rico was once a large and thriving coral reef. Over time, the remains of the reef's marine inhabitants were deposited and carbonate rock was formed. Eventually geologic movement in the crust thrust the limestone seabed upwards forming the "haystack-like" limestone mountains called Karst topography.

Karst is characterized by how it reacts with water. Being composed of calcium carbonate, the limestone reacts with mildly acidic water and begins to dissolve away. This chemical interaction is what produces a labyrinthine landscape riddled with sinkholes and underground caverns. It is this rugged terrain that harbors the richest diversity on the island.

Some rivers, like El Río de Camuy, pass through this karstic area in the tropical North of Puerto Rico and disappear under the surface and then reappear various kilometers down hill.
Where the river leaves the sun to travel beneath the ground is the site of Rio de Camuy Cave Park.

First glimpse into the mouth of Cueva Clara

From inside, looking out at the Eastern mouth of the cave

Looking up at the sinkhole that is the western cave entrance

We also got to visit a lesser known cave, Cueva Ventana, or Window Cave. There was no entrance fee or tour guide, not even a handrail or paved steps leading down into it. To get to it, all you have to do is park at a gas station on the side of the road, and hike up the hillside following a dirt path. Eventually it will take you to a hole in the ground just beneath the spreading roots of an old tree.

Once you climb down, minding the wet moss covered stones and muddy slope, you find yourself in darkness. There are no electric light displays. Without a flashlight you could not see that the floor of the cave is smooth and slippery showing the bumps and wavy patterns that water makes during its swift passage. Making our way through the cave, we begin to notice certain characteristics common in public places. The first thing you notice is the smell, like urine and maybe worse things. There is also obvious vandalism in the form of graffiti and carvings, as well as broken stalactites/stalagmites. The stone formations that do remain are a slick black from the hundreds of oily little hands that have grubbed them up, arresting their growth.
Progressing through the passages you can begin to see some sunlight ahead.