Archaeology can be tough can’t it? Trowelling, swinging a mattock, the enless rain or the blazing sun on your back. Phew its a rough old world… Alright who are we trying to kid here? Its a doddle. Easy peasy lemon squeesy and would you like a digestive or a tunnocks teacake with your afternoon tea?
Archaeology is rarely too difficult, demanding, exhausting or life threatening on dry land. Don’t get upset, I love it and love archaeologists too. All I am saying is that it isn’t an ‘extreme’ pasttime. However, underwater archaeology is a different matter altogether. Show me an archaeologist in a wetsuit and I will show you someone worthy of enourmous respect. Each time a marine archaeologist goes under water, they battle to overcome very real and scary dangers and almost insurrmountable practical difficulties.
Physiological constraints of underwater excavation include the necessity for the archaeologists to be trained divers. Even with training, there are potentially lethal dangers in underwater archaeology. Firstly there is nitrogen narcosis, of which Jaques Causteau said; “I like it and fear it like doom. It destroys the instinct of life” Nitrogen is an inert gas harmless at sea-level but toxic at pressure. The effects are similar to drunkenness and can lead to the divers putting themselves and others at risk. When ‘the raptures of the deep’ hit you it takes a massive effort of will to keep focused on the job in hand and avoid lethal mistakes such as taking your regulator out of your mouth to blow bubbles at the passing fish.
Next there is the severe cold. Although a diver might be in tropical water that feels lovely at the surface, temperature drops rapidly with depth. Water conducts heat away from the body, so even when fully suited in neoprene, divers must battle hypothermia if they intend to spend any length of time below the surface.
Next there is decompression sickness, commonly known as ‘the bends’. Embolisms caused by the expansion of nitrogen bubbles in the blood due to rapid lowering in environmental pressure when ascending from a dive site can produce effects ranging from muscle pain, through paralysis to death. Decompression sickness is a major factor on underwater excavation as it affects the depth and bottom-time that can be reached. If a wreck is deeper than 30 metres compressed air needs to be replaced with Nitrox or other Gas mixes which in turn impose their own complications upon the operation since further training is required before a diver/archaeologist can use them safely.
In addition there are the dangers of being dragged out to sea by strong currents, being trapped within a wreck, getting lost in low visibility due to silt particulates in the water or being injured by underwater fauna and flora: anenomies, lionfish, sharks and fire coral to name but four from an extensive list.
Digging is almost impossible because as you wave the surface silt away, visibility drops to something approaching zero and then the silt you just removedsettles back in exactly the same spot, covering your site.
The above points, combined with the economic and technological constraints of being able to affording scuba equipment, support divers, silt removal systems, navigation using Global Positioning by Satellite and support boats mean that underwater excavation is a proposition of a completely different order to land based archaeology. Next time you meet a marine archaeologist…show a little respect.