With 2010 kicking into high gear, despite the frigid New England weather we’ve had the past few weeks, it’s back to business as usual for many marine contractors. Just this past week I started a major rehab project of a submerged railway system used for launching and hauling large ferries and other transport vessels. This is not my first project of this type, but the circumstances of this work brought some realizations to ‘light’.

Two issues exposed some striking realities to be considered for spending any time living beneath the waves. First is sedimentation. Just like the ocean’s surface can range from glass calm to frothy turbulence, the ocean bottom’s sediments move in waves, though much slower. Hundreds of cubic meters of sand and silt can be moved in relatively small areas, burying everything in its way. This is a significant problem for any undersea structures. In the case of my railway, five decades of silt and sand completely bury the supporting structure of the rail system. To be maintained, the entire structure needs to be excavated. Again, no simple task given that any sediments removed are likely to end up right back where they started. Any undersea structure needs to be placed where moving sediments will not impede its function, or safety for any undersea visitors/operators.

This brings us to point number two…visibility, or rather turbidity. Working on this railway is in ZERO visibility. It is hard to describe how black it can be underwater. For folks who have never visited underwater, it is an impossible situation to create. Even with your eyes closed, light coming through your eyelids is sensed to some degree by your brain. Underwater, with all ambient light being absorbed by the environment, coupled with 100% turbidity from mud and silt, your eyes can be wide open with pupils fully dilated, and you can feel your brain straining to catch a glimpse of something – anything. But it is not there. I’ve actually found it easier to close my eyes and work by feel, allowing my eyes to rest. For the past three days, I’ve spent six hours a day in these conditions. Coupled with our short winter days, I haven’t seen much daylight. This physical and psychological strain is not for everyone, probably not for even a fraction of a percent of our population…but it is still a reality to be faced given humans need to construct and maintain coastal structures.

These are just two of the many environmental constraints that should be considered as we press forward to the concept of living underwater. Despite the huge volumes of water out there that offer prime real estate options, the realities may very well be that the practical ability (within human limitations) to maintain the structure due to both shifting bottom sediments, and thick turbidity is just not possible in a large percentage of it. These conditions would be prohibitive of any routine excursions from the undersea structure, and thus not possible to harvest natural resources.

That being said, it is somewhat obvious why the majority of past and present life in the sea programs have been launched in subtropical and tropical habitats. It is true, that even within the reach of our species on our own planet, that there are conditions that are beyond reasonable psychological limitations of our species. However, these may very well be the places where we can learn the many lessons necessary for a new life in the sea, and most impotantly, learn more about ourselves.