<P> To enable her to probe the depths, 15 of Challenger's 17 guns were removed and her spars reduced to make more space available . Laboratories, extra cabins and a special dredging platform were installed . Challenger used mainly sail power during the expedition; the steam engine was used only for powering the dredge . She was loaded with specimen jars, filled with alcohol for preservation of samples, microscopes and chemical apparatus, trawls and dredges, thermometers, barometers, water sampling bottles, sounding leads, devices to collect sediment from the sea bed and great lengths of rope with which to suspend the equipment into the ocean depths . Because of the novelty of the expedition, some of the equipment was invented or specially modified for the occasion . In all, she was supplied with 181 miles (291 km) of Italian hemp for sounding . </P> <P> On her 68,890 - nautical - mile (127,580 km) journey circumnavigating the globe, 492 deep sea soundings, 133 bottom dredges, 151 open water trawls and 263 serial water temperature observations were taken . Also about 4,700 new species of marine life were discovered . </P> <P> The scientific work was conducted by Wyville Thomson, John Murray, John Young Buchanan, Henry Nottidge Moseley, Alphonse François Renard and Rudolf von Willemoes - Suhm . Frank Evers Bed was appointed prosector . The official expedition artist was John James Wild . As well as Nares and Maclear, others that were part of the naval crew included Pelham Aldrich, Lord George Granville Campbell, and Andrew Francis Balfour (one of the sons of Scottish botanist John Hutton Balfour). Also among the officers was Thomas Henry Tizard, who had carried out important hydrographic observations on previous voyages . Though he was not among the civilian scientific staff, Tizard would later help write the official account of the expedition, and also become a Fellow of the Royal Society . </P> <P> The original ship's complement included 21 officers and around 216 crew members . By the end of the voyage, this had reduced to 144 due to deaths, desertions, being left ashore due to illness, and planned departures . </P>

Where did the challenger expedition collect marine organisms