Saturday, August 04, 2007

Shark Week

This week has been Shark Week on the Discovery Channel, always a big deal for me. I can't get enough of shark documentaries, I find them fascinating. There's just something about these animals that are so graceful, powerful, and beautiful, animals that have been around since long before the dinosaurs roamed the earth (they've been around for 400 million years) that puts me in awe. There are about 400 different species, that range in size from about a foot long for the pygmy shark, to 60 feet long for the whale shark. The two largest fish in the ocean, the whale shark and 40 foot basking shark, eat some of the smallest fish in the ocean, krill. Great White sharks have been known to launch themselves out of the water in sometimes acrobatic displays, hunting seals around one particular island off of South Africa. This is the only place in the world where they do this, influenced largely by the underwater topography around the island. There are sharks that live in the deep ocean, at depths that would crush many submarines, and sharks that can live for years in fresh water. They have not five senses, but six; they can sense the electric currents given off by other living things, boats, etc, and use them to hunt. People who've worked closely with them have noticed different individuals exhibiting distinct personalities. This is just scratching the surface of what I've learned about them over the years, and there's still so much we don't know.

Of course, this fascination with sharks in particular is just an extension of my interest in marine biology as a whole. Since I was a kid, growing up on a lake, I've been intrigued by the water, mostly the ocean, and its flora and fauna, and even topography. I think it's largely because it's a world that's so alien to us, that we can only visit for any length using modern technology, and the deeper you want to go, and the longer we want to stay, the more advanced the technology required. A world that is still so largely unexplored; for all they've learned, scientists have still only barely scratched the surface.

Some people may look at fish as "just fish", but I see animals that can survive in an environment that I can only visit, animals in wide varieties of incredibly beautiful colors and shapes to rival anything on land, that are often wierder than any alien in the best sci-fi movies; animals that often exhibit surprising intelligence, that live in conditions more hostile than anything we can imagine. Take the hot vent ecosystems in the deep abyssal plains, where hot water is vented into the ocean from the earth at temperatures of 800 degrees. Celcius. Yes, there is life around these vents, in ecosystems which are based not around sunlight and photosythesis as the chief energy source, like those on land and in shallower areas of the oceans, but chemosynthesis, in which hydrogen sulfide is broken down into sugars. This occurs at depths that would crush the human body. This is an environment that is so alien to us, it may as well be on another planet. But it's here, on Earth, and it's teeming with life.

A friend once told me they didn't understand the attraction of keeping a fish tank. I'm sure the answers to that question would vary widely from person to person, but for me, when I was a kid and we had fish tanks, it was about having a piece of nature right there in our home, like we had this little ecosystem in our livingroom. If I were ever to get a fish tank, that's what it would be again, along with the pride of nurturing that ecosystem. Not to mention, well designed tanks are just really, really cool. Often very beautiful. When I was in college, a roommates boyfriend had a beautiful saltwater tank, that was designed to look like a mini reef. It had colorful anemonies, shrimp, and a variety of colorful fish. It was as beautiful, if not more so, than many paintings I've seen. I would keep a tank like that in a heartbeat, if it weren't so expensive.