Posted by: Merlin PJ20 JAN 2010
Today, 23 January (2010), sees the 50th anniversary of the descent of the US Navy bathyscaphe Trieste to the deepest known point of the Pacific Ocean, in the Challenger Deep. This is the deepest point of the Marianas Trench, which lies in the Western Pacific some 1,800km east of the Philippines.
The Challenger Deep was discovered in 1851 by scientists working on board a British ship, the Royal Research Ship Challenger II, and named after their vessel.
The Trieste was designed by the Swiss scientist Auguste Piccard and was built in Trieste, on the border of Italy and the former Yugoslavia. After being used by Piccard for a series of dives in the Mediterranean, the vessel was purchased by the US Navy in 1958.
The Trieste consisted of a buoyancy chamber which was filled with petrol and a spherical pressure sphere for the crew of two. It has been described as the underwater equivalent of a lighter-than-air aircraft.
The cramped crew compartment had a single window made of a cone of acrylic glass (Plexiglass) for direct observation, and there were two powerful arc lights in their own pressure compartment. However, these could only be used intermittently, because the heat generated by the lamps caused the water to boil violently around the lamp housing.
On 26 January 1960 the Trieste descended to the floor of the Challenger Deep, a depth of just over 10,900m, carrying Jacques Piccard, the son of the vessel’s designer, and Lieutenant Don Walsh of the US Navy. Merlin is happy to record that the Trieste returned safely to the surface, in spite of a crack developing in the outer Plexiglass window during the dive. No one has reached such a depth since, although there have been deep dives by a number of unmanned vessels.
Piccard and Walsh were amazed to see life on the sea floor at the limit of their dive. There were a number of small fish, which they described as similar to flounders and sole, and they also saw shrimp-like creatures and a jellyfish. For such life to exist, there must be oxygen dissolved in the water, so it would seem that the water at such a depth is not stagnant, but must be replenished by ocean currents.
So here is a memo to those in authority: please do not use deep ocean trenches for the dumping of toxic waste!