Dive number 7!
Mar. 17th, 2007 05:22 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
gmonkey42I went on another dive today, as you can see from the new icon.
I volunteered with the Monterey Bay National Marine Sanctuary to remove an invasive species of kelp from the Monterey harbor (you can just barely see the masts of some boats behind me). It was fun! We had to go up and down the pylons, looking for the kelp. It was only 15-20 feet deep. I had an 80 cubic foot tank this time - I've used a 60 in the past - and I went from 3000 psi of air to 800 when I was done (500 is considered "low") I forgot to check the time but that's probably the longest dive I've been on. On the other hand, I had to use more air than usual because we kept going up and down* so it might not be as long as I think. It didn't seem very long.
As far as sightseeing, there were cool decorator crabs, nudibranchs (sea slugs), hermit crabs, big-ass sea stars, a few tunicates (urochordata!), and some big, squishy white things that I'm still trying to figure out what they were. Some kind of cnidarian, probably. They were poofy like a chef's hat. Ooh! And one big sea cucumber. Those are cool. I wanted to pet it but I decided to leave it alone. So many things in the ocean that I want to pet and hug! Must resist the urge!
My buddy and I didn't actually find any of the kelp but another team found a little on their side. They're trying to get a year's worth of data on this species so the organizer said it's important that we were here to collect the data even though we didn't get to clear out much kelp today. I know that. A negative result is still a result! And maybe the lack of the kelp is a good sign that the project is working.
*The technical reason why going up and down required so much air, in case anyone's interested: divers use a buoyancy control device (BCD) to float or sink. It's a vest (and it often has nifty little rings where you can clip all your stuff. The one I rented also had integrated weights, which is a nice feature so you don't have to wear a separate weight belt) that hooks up to your air tank and there are valves where you can inflate or deflate it. So when I want to go down, I let some air out and then when I want to go up, I have to let in some more air from my tank. An added complication is that as you get closer to the surface, the air already in the BCD expands (because there's less pressure from the water around it, like how the air pressure is lower in the mountains than at sea level). Therefore without changing the amount of air in your BCD, you're more buoyant at shallow depths than you are at deeper depths.
ETA: I found a picture of those poofy white things. They are anemones. Ignore the fish. Check out the rest of this guy's photos too, they're amazing.
I volunteered with the Monterey Bay National Marine Sanctuary to remove an invasive species of kelp from the Monterey harbor (you can just barely see the masts of some boats behind me). It was fun! We had to go up and down the pylons, looking for the kelp. It was only 15-20 feet deep. I had an 80 cubic foot tank this time - I've used a 60 in the past - and I went from 3000 psi of air to 800 when I was done (500 is considered "low") I forgot to check the time but that's probably the longest dive I've been on. On the other hand, I had to use more air than usual because we kept going up and down* so it might not be as long as I think. It didn't seem very long.
As far as sightseeing, there were cool decorator crabs, nudibranchs (sea slugs), hermit crabs, big-ass sea stars, a few tunicates (urochordata!), and some big, squishy white things that I'm still trying to figure out what they were. Some kind of cnidarian, probably. They were poofy like a chef's hat. Ooh! And one big sea cucumber. Those are cool. I wanted to pet it but I decided to leave it alone. So many things in the ocean that I want to pet and hug! Must resist the urge!
My buddy and I didn't actually find any of the kelp but another team found a little on their side. They're trying to get a year's worth of data on this species so the organizer said it's important that we were here to collect the data even though we didn't get to clear out much kelp today. I know that. A negative result is still a result! And maybe the lack of the kelp is a good sign that the project is working.
*The technical reason why going up and down required so much air, in case anyone's interested: divers use a buoyancy control device (BCD) to float or sink. It's a vest (and it often has nifty little rings where you can clip all your stuff. The one I rented also had integrated weights, which is a nice feature so you don't have to wear a separate weight belt) that hooks up to your air tank and there are valves where you can inflate or deflate it. So when I want to go down, I let some air out and then when I want to go up, I have to let in some more air from my tank. An added complication is that as you get closer to the surface, the air already in the BCD expands (because there's less pressure from the water around it, like how the air pressure is lower in the mountains than at sea level). Therefore without changing the amount of air in your BCD, you're more buoyant at shallow depths than you are at deeper depths.
ETA: I found a picture of those poofy white things. They are anemones. Ignore the fish. Check out the rest of this guy's photos too, they're amazing.
