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positioning system, which enables it to occasionally Þ x its exact position while submerged. Finally, the AUVÕs standard loadout includes an Imagenex 852 forward-looking Echo Sounder for detecting unexpected obstacles and a ParoscientiÞ c 8B7000 pressure sensor, which helps the vehicle maintain a con- sistent depth.GEOMAR has used ABYSS to study seaß oor volcanism around the world since its Þ rst cruise in 2009; so far, the vehicle has been used on scientiÞ c expeditions to the Greenland conti- nental slope, the Southern PaciÞ c, the Central Indian Ridge and the south Atlantic. Currently, the AUV is being used to survey previously unexplored hydrothermal vent sites in the Atlantic south of 10¡S, with the aim of testing a model proposed by Prof. Devey for the relation of hydrothermalism and volca- nism. This cruise is a continuation of previous work by GEOMAR studying the Mid-Atlantic Ridge, and will focus on the section between 13¡ and 33¡S.ÒData from our previous expeditions suggests that hydrothermal activity is nearly constant on marked within-axis volcanic highs, but relatively rare at deeper parts of the axis,Ó said Prof De- vey. ÒSince the individual seaß oor vol- canoes in the deeper parts of the ridges in this region likely have a timescale of activity on the order of thousands of years, weÕre using geography as a proxy for time on this cruise. Instead of moni-toring a single area of the ridge for an eruption to study, weÕre using the long dive times ABYSS makes possible to cover roughly 100 km every 36 hours. At that rate, we expect to encounter and examine nearly 2,000 volcanoes during the expedition, and, using our conserva- tive eruption rate estimates, at least two of those will have erupted in the last year. Data from these recent eruptions will be critical to testing our model.Ó In addition to the AUVÕs applications in seaß oor volcano research, ABYSS has also been used by GEOMAR for numerous other projects, including deep sea mineral exploration. Marine Technology Reporter 23www.seadiscovery.com MTR #4 (18-33).indd 23MTR #4 (18-33).indd 235/7/2013 4:16:01 PM5/7/2013 4:16:01 PM