Saturday, January 17, 2009
I post on this blog things about nature every once and a while, and I felt the need to do so after watching an episode of National Geographic Explorer entitled Jellyfish Invasion (while I was eating a tuna sandwich, no less). It's been a while since a nature program made my jaw drop, so I had to share. (The on-demand version I watched apparently split the original episode into two parts, so I missed the half on how jellyfish sting people, for which I'm rather glad.) Now, when we look at jellyfish like those in the picture above, we usually have one of two responses. Some people think they're beautiful, wisping through the water in gelatinous form, glowing in iridescent colors not unlike nebulae in space. Others see them and think of the venomous sting their tentacles can cause you in the water. I'm somewhere in-between in my opinion, but after seeing this show, I'm not sure how I feel. Apparently in the past few years there has been an explosion of jellyfish all around the world. In the United States, the largest area hit has been in the Gulf of Mexico (my family will love this). Jellyfish normally come and go, but now they're populating at an exponential rate and in doing so they are threatening ecosystems, forcing other fish and animals to leave, if not killing them with their poisonous limbs. As a result, fishing industries are being affected (of course economic impact is why people are most concerned). Jellyfish have been around for over 500,000,000 years. They are some of the oldest surviving species on our planet. Yet, they have no brain, skeletal structure, or power of locomotion (they move with the current in the water). Why the population explosion? Apparently we're to blame. As we overpopulate, we increase waste and pollution, and this dynamic change is causing areas of water to become dead zones for most of nature. Jellyfish, however, thrive in these dead zones, since pollution doesn't affect them, and from there they move into healthy channels of water. Wait. It gets better. Global warming is affecting them as well. Subtle changes in water temperature are causing them to reproduce faster. Apparently there are government-sponsored programs (in Japan, for instance) that are working to get rid of the jellyfish by slaughtering them. However, this plan is apparently backfiring. (Here's the part where my jaw dropped.) Jellyfish have millions of eggs and sperm, and when their lives are threatened, they instantly release all of their microscopic reproductive cells, which commingle and spawn polyps. These polyps rest on surfaces underwater--up to thousands of feet in the ocean, no less--and over time they, quite literally, just pop out new jellyfish! (It's like the mythological nine-headed hydra who, whenever someone cut off a head, grew three more in its place.) So what we're saying here is that for every jellyfish that is killed, a million new polyps are created that can generate tons of new jellyfish, and subtle changes in water temperature from pollution and global warming are causing it and their invasion. Not only are we causing the problem, but our current solutions are making it worse. Exciting, huh? My favorite part of the episode was the end, when the narrator said in a doom-and-gloom voice, "The age of the jellyfish is returning, and somehow man is going to have to learn how to live in harmony with them." Boy, I can't wait to get back into the ocean now! Here's a video clip via YouTube about the full episode (if you don't see it below, click here).