No, this won't be a column about underwater sex so even the youngsters can read on. It is about a subject that I never thought I'd be writing about, and the topic may get a bit too deep for some. We'll see. Back in the early 1960's when I first started "experimenting" with Jacques Cousteau's AquaLung, I was smart enough to know it was new technology and to use it cautiously. My dives in those days were in fresh water and rarely went below 20 feet. However, when I moved to Catalina and easy access to the ocean, I had the opportunity to explore beyond those safe limits. For the most part I still stayed within about 60 feet of the surface since my research focus, the giant kelp, was largely in those depths.
For many years I considered anything in the 80 to 100 foot range a deep dive. I made them on occasion, but not frequently. Perhaps it was my first dive to 90+ feet that conditioned that. My buddy was one of my students, Gary Maul, from the old Catalina Island School for Boys formerly located in Toyon Bay. He wanted me to take pictures of an unusual worm he had seen at that depth. Gary and I grabbed two tanks from the "filled" rack, donned our primitive gear and walked to the surf zone with my trusty Nikonos underwater camera in hand. In those days I wore no BCD, no pressure gauge to measure air in my tank, and no octopus (second regulator) as backup. Very few divers did.
Gary and I got to depth and found the worm, but just as I was about to take the pictures I noticed my regulator was drawing hard. I reached back to pull the rod on my J-valve to open my reserve... but it was already down. Just then Gary signaled he was getting low on air and his J-valve rod was down as well. Merde as the French say! We made our way slowly back to the surface by buddy breathing what little was left in our tanks (a technique apparently no longer taught my some agencies). I decided to remain at safer "depths" (or should I say "shallows") in the future.
For decades I rarely dove to 100 feet and almost never beyond that. My deepest dive was in the clear waters of Fiji. There I descended to nearly 150 ft trying to follow the idiotic Aussie dive buddy I had been assigned by the dive master at the Jean-Michel Cousteau Fiji Islands Resort. He had clearly stated before the dive he wasn't going to abide by the rules. With my usual clear headedness, I decided I wasn't going to dive with him and signaled to the dive master to come get him while I ascended to join the main dive group at 80 ft.
Recently I've been diving at a number of Catalina sites where deep dives are quite possible. As Tim and Chris, the dive masters on Scuba Luv's King Neptune, like to say... look at the hills and imagine those steep slopes continuing underwater. Yep, it can really drop off fast at many locations. Over the past few months I've explored deeper depths in search of species of interest. At first it was just down to 120-130 ft to look for the sea pens and the sand burrowing brittle starfish I've written about previously. I've also looked for angel sharks in that depth range (with far less luck). When the squid runs started this winter, I dropped down to 153 ft at Yellowtail Point which broke my all-time depth record... permanently I thought. Keep in mind that the Casino is only 140 ft. high!
A few weekends ago I went out on the King Neptune to Wet T-Shirt, a dive site located just past the East End Quarry. The boat anchor was supposed to be in 100 ft. so I dropped down the anchor line toward it. It actually rested at 140 ft on a very steeply sloping bottom. I started looking for squid, or at least their eggs, but encountered none. I did find a very large clam sitting on the dark bottom sediments and started to film it. I used my hand to reposition it for a better shot... and to my surprise it started sliding down the slope fast enough to kick up quite a dust cloud! I ended up going down to 182 ft, and did find scattered squid eggs down there. The egg clusters had probably tumbled down the slope and broken up.
Why did I stop there when 200 feet was easily within reach? Essentially because I knew I had an obligation to my readers to write the next column. And, of course, I'm in no hurry to die! Although we all survive by breathing oxygen from our atmosphere (yes, even smog ridden LA has some), were you aware that under certain conditions it actually becomes not only toxic, but deadly? As a diver goes deep, the partial pressure of oxygen in their tank increases from 0.21 (21%) at the surface to about 1.40 at 180 ft. It becomes deadly at a partial pressure of about 1.60 which is reached at depths in excess of 210 ft. I have no intention of going that deep on straight air, believe me (although others have)!
Another consideration during such deep dives is nitrogen narcosis. This effect, caused by absorbing nitrogen from the mix in a SCUBA tank (remember, air is nearly 80% nitrogen), can cause a diver to become goofy (yes, even goofier than they are at the surface). It can hit some divers at depths as shallow as 60 ft, others much deeper. The deeper one goes, the greater the chance of narcosis and the greater the chance of clouded judgment. I first tested the effects of nitrogen narcosis while diving to 100 feet off the Great Barrier Reef in Australia. I measured a noticeable decline in my reaction time while doing a puzzle. Fortunately I don't seem to be seriously affected by narcosis. I usually measure this subjectively by seeing how well I focus on my videography, how well the subjects are framed and how smoothly I can follow any motion. Even at 182 ft. I seemed to be doing fine. Fortunately the effects of narcosis disappear when one returns to shallower water.
The last consideration is "the bends" or decompression sickness. This is caused by the absorption of nitrogen gas into various tissues in the body. Depth and duration of the dive are two important factors in this process. If a diver returns too quickly to the surface, nitrogen may bubble out of the tissues into the blood stream. These bubbles can them cause a stroke-like embolism by blocking the smaller arteries. To avoid these potentially deadly effects, divers return to shallower depths slowly, and make safety stops in shallower depths to "offgass" or decompress. In 45+ years of diving I've never experienced any problem with the bends, but I have seen a number of divers who have... with death resulting in some cases. On this dive I never even went into decompression so I kept within the limits of a no decompression dive.
However, several of my buddies and dive friends have expressed concern over my recent deep diving. So I'll continue to descend to "reasonable" depths (beyond 100 but no more than 150 ft) in my search for new critters to film for your viewing and reading pleasure. But I'll do so carefully. After all, I have a son, my family, and my friends to consider. Some day I'll get mixed gas (oxygen-nitrogen-helium) training so I can dive to depths of 250 feet and film the extensive beds of brachiopods that Bob Kennedy found at those depths. Now, in closing, what does the title have to do with this column? Well, the record-setting site was Wet T-Shirt, and Jacqueline Bisset wore one underwater in the classic 1977 film "The Deep." Jessica Alba is currently vying to unseat Bisset with her performance in the 2005 remake of that film, retitled "Into the Blue." I won't take sides... either lady could be my dive buddy... shallow or deep!
© 2006 Dr. Bill Bushing. Watch the "Dive Dry with Dr. Bill" underwater videos on Catalina Cable TV channel 49, 10:00 AM and 5:00 PM weekdays. Please help me climb out of self-imposed poverty... buy my "Munching and Mating in the Macrocystis," "Great White Sharks of Guadalupe," "Calimari Concupiscence: Mating Squid, "or "Giant Sea Bass" DVD's. Yes, take Dr. Bill home with you... we'll both be glad you did!
Dive profile from my "record setting" dive to 182 feet at the Wet T-Shirt dive site near the East End Quarry.
This document maintained by
Dr. Bill Bushing.
Material and images © 2006 Star Thrower Educational Multimedia