Everything comes to an end, of course, but the conclusion of this mission seems to have arrived unreasonably quickly. Today is the last day that we can spend time freely outside the Aquarius habitat. Tomorrow we must be inside by 1000 AM to prepare for decompression.

Decompression is always the last phase of saturation diving. An underwater habitat offers two special advantages. One is simply the proximity to the reef and the ability to observe the environment from a refuge that contains comfortable and commodious living quarters as well as a full-featured laboratory. The more important benefit is less obvious. Living in an environment where the air pressure is identical to what one breathes on SCUBA minimizes or even eliminates any danger of decompression sickness (commonly known as the "bends"). This ailment is caused by the formation of nitrogen bubbles in tissues when surfacing, and it cannot occur if the pressure of nitrogen in the air remains constant. This means that we can spend all day outside at the depth of Aquarius (about 50 feet), and we gain hugely increased diving time at other depths - up to 6 hours (which is practically the entire work day) at depths less than 95 feet.

Of course, this does not come free! Because our bodies are now saturated with air at a pressure 2.5 times that at the surface (which is where the term "saturation diving" comes from), we can't just go home whenever we want, nor can we ever ascend above that same 50 foot limit while we're living here here. Our training enforced the rule "Solve your problem on the bottom! The surface is not a refuge in an emergency!" If we went there, our blood would fizz like a soft drink in a shaken can. To get back up there, we must gradually reduce the pressure we live in. This takes place right here in the Aquarius habitat, and we will describe our decompression experience to you once it begins tomorrow.

Meanwhile, we are frantically trying to get that last item of data, that last little experiment, that last critical bit of information before we resume our air breathing ways! We believe our work can make a difference, and we're committed to extracting all we can from this special experience. We already are beginning to think like fish and hunt like mantis shrimp - the final step will be to truly feel the danger that haunts our beautiful reefs and to find the means and vision to bring about the change that must come.