Living in a Bubble: 10-21-08 Luis Camilli
I feel the pressure wave in my ears first, then looking through the starboard port window see a whole school of fish and floating “marine snow” move simultaneously with the surge of ocean swell which rocks the Aquarius Habitat in passing. Thank goodness we are moored to the bottom with heavy cables, otherwise we might be visiting the surface sooner than expected! Nonetheless, business goes on as usual, and we spend several hours graphing and reviewing the day’s scientific data and planning our dives for the next day. I occasionally glance up at the flashing digital display of other numbers; the life support data showing available air pressure and percent of oxygen and carbon dioxide in our chamber air.
Among many tasks on the daily checklist is to change out the buckets of soda lime for our carbon dioxide scrubbers in the Habitat. Why do we have to “scrub” the CO2 out of the air? Well, essentially as our bodies use the available oxygen in the air to convert sugars into energy for cellular processes – everything from firing neurons, to heart contractions, fighting infections, or digesting dinner – the result is the production of carbon dioxide as a byproduct of these physio-chemical processes referred to as cellular respiration. Given that at any given time there can be up to six people living in a cylinder the size of a bus may give you an idea of how much respiration is going on inside of Aquarius – incidentally related to similar chemical processes we are studying on the reef outside.
In fact, earlier in the day we placed a couple of cylindrical enclosures (about the volume of the inside of a washing machine) around various sponges and used stable nitrogen isotope tracers to see how long it would take the sponges to respire. The enclosures, while circulating the existing water with submerged pumps, ensure that no “fresh air” reaches the sponges during our experiments. For awhile, it looked as if the sponges were in an intensive care unit, hooked to tubes leading to a mass spectrometer and nitrate/pH sensors complete with hanging “I.V. bags”. What we are seeing is that it doesn’t take long, sometimes a matter of a few minutes, for these sponges to respire and significantly change the pH and level of dissolved gases (i.e. oxygen, nitrogen, carbon dioxide) in their immediate environment.
Living underwater at Aquarius and conducting these experiments makes me realize just how critical (and difficult) it is to maintain the necessary balance to sustain life in an environment that is different from your own. In some ways the Aquarius Habitat can be thought of a microcosm of life on earth. We as humans – like other animals, require a unique mixture of earth, wind, fire and water. This may seem a little obvious until you consider the broader implications of rapid environmental change we are noticing on our planet. This little pressurized bubble called Aquarius literally means the world to me – it is a habitat that I can’t live without.
Aquanaut Luis Camilli
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