MALTA_DIVER:
I still not convinced that whales/marine mammals can get bent.
It seems like there are two issues in this one thread - maybe they should be broken out into two threads:
1. Can whales get DCS? I don't know why it's so hard to believe. It's the same physics that applies to divers, and although our physiology is different, so is our capacity for deep diving. Breathing compressed air is not necessarily relevant. If a human could take a single breathe of air, dive to 2000 feet and stay down there for 45 minutes, then he/she is at risk for DCS, depending on how fast he/she comes up. Dive Training magazine has an article last year about DCS in whales. Scientists showed that deep diving whales have bone degradation that is consistant with DCS. They theorized that the whale brain has a pretty sophisticated "dive computer" inside it that tells the whale what a reasonable rate of ascension is, based on their dive profile. That's not so hard to believe, considering these creatures evolved to be able to do just that. Older whales were more likely to show evidence of past DCS trauma, suggesting that in their longer lives, they made more mistakes or took more risks while diving. If a whale gets DCS, they've dived too deep, for too long, followed by a rapid acsension (or at least too rapid for that dive). Maybe that particular giant squid that lived kinda deep looked so juicy, they couldn't help themselves
2. Does SONAR cause DCS in whales? I think this one is a stretch - it's possible, but it would be very difficult to prove. You would have to tag a whale, get it to dive deep, then blast it with sonar to see if it scares the poor beast to a rapid ascension. Either that, or cage it and do doppler studies of SONAR on their very tissue while blasting it with SONAR. Either way, it's an invasive study.
Environmentalism is valid and necessary, but sometimes environmentalists go a little too far with pseudo-science and conjecture. I'd like to see more funding of environmental research so that we can show hard evidence of what is really going on, and then we can figure out how to solve the problem.