Visiting an alien planet... on Earth


Visiting an alien planet... I don't know how else to describe the experience of exploring underwater. "Alien" can be defined as "coming from another world." To a terrestrial, air-breathing, homeothermic bipedal hominin, being underwater can only seem like being, well, on a different planet. There's a reason astronauts train in a pool to experience "neutral-buoyancy" diving to simulate the weightlessness of space travel. And creatures have been evolving in Earth's seas for a LONG time. Complex life appeared in the Earth's history about a half billion years ago.

"The basic body plans of all modern animals were set during the Cambrian Period, 542 - 488 million years ago."

Since then, species have come and gone (mostly gone), but if you visit a thriving reef environment, you won't even think about what has disappeared, because there is just so much still there!

This week we (Caroline, Wes and Mignon) went on a dive trip in the Caribbean Sea around Cozumel and in the cenotes near Tulum, in the Yucatán.

Cenotes are surface connections to subterranean water bodies. They are formed from the dissolving of limestone bedrock, followed by a collapse of the roof. 

Stalagmites and stalactites were formed when ocean levels were lower during the ice ages, then filled with water as the sea level rose.

We started off with 3 dives in various cenotes, including the Pit, then Dos Ojos (the Barbie line), and Dos Ojos (the Bat Cave line). "Lines" refer to the ropes you needed to follow to avoid getting lost. These were all cavern dives as opposed to cave dives. When cavern diving, you have to be able to see natural light the entire time that you are exploring the cavern, as opposed to a cave dive where no sunlight penetrates. Cavern diving it may have been, but when you put your palm over your flashlight, it was dark!

In the 100+ foot deep cenote "The Pit", you swim through a halocline layer at around 50 feet (where a body of freshwater sits on top of salt water, where you wonder what has happened to your eyesight), and just over a smoky hydrogen sulfate layer (sulfuric acid). Diving in fresh, salty, and hydrogen sulfate water... alien!

Then we took the ferry to Cozumel to dive in the Arrecifes de Cozumel National Park. Wesley took some great photos.

If Mignon is your dive buddy, she is unmistakable!

Visiting an alien planet...


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