Page 20: of Marine Technology Magazine (May 2013)

For most of human history, the size and depth of the Earth?s oceans have made it nearly impossible for surveyors and scientists to collect valuable and comprehensive data on the sea oor. In recent years, this led to the question: ?Why is it that we cannot map our own planet as well as we?ve mapped the Moon and Mars?? Since the development of sonar instru- ments at the turn of the 20th century, surface ships have been the primary means of bathymetric data collection and sea oor study. The near extinction of sunlight and electromagnetic waves in general at depths beyond 100 m, however, limits op- tical imaging underwater. Acoustic signals of relatively long wavelength penetrate to great depths; however, the resulting bandwidth from a surface ship is fairly small. Thus, the high- resolution of optical and acoustic images obtained in shallow water is not readily possible at abyssal ocean depths?until very recently. Recent advances in autonomous underwater vehicle (AUV) technology have revolutionized 21st century oceanography. AUVs routinely descend to depths that manned submersibles can reach only with great dif culty, great expense and high risk to human life. AUVs allow researchers to collect high- resolution sea oor data faster and more reliably in deep water than ever before. One organization on the forefront of scienti c AUV deploy- ment is the German research facility GEOMAR ? Helmholtz Center for Ocean Research Kiel. Using a specially designed REMUS 6000 type AUV called ABYSS, scientists at GEO- MAR are exploring sea oor regions at depths up to 6,000 m, and have collected geological and bathymetric data of un- precedented quality. The ABYSS has explored several deep sea oor regions with tectonic and volcanic activity that was previously unmapped. For example, recent multidisciplinary studies of hydro- thermal vents on slow spreading ocean ridges have bene ted greatly from data collected with the ABYSS. The studies re- veal a remarkable diversity of hydrothermal systems in the At- lantic, Indian and Arctic oceans. When hydrothermal systems were  rst discovered on the East Paci c Rise and other Paci c Ocean ridges in the late 1970s, the community consensus held that the magma delivery rate of intermediate to fast spread- ing ridges was necessary to support black smoker-type high- temperature systems, associated chemosynthetic ecosystems, Hydrographic Survey Exploring the Abyss GEOMAR & theABYSS AUV Study the S. Atlantic Sea oorBy Graham Lester, Director Hydroid Europe May 201320 MTRMTR #4 (18-33).indd 20MTR #4 (18-33).indd 205/6/2013 10:52:12 AM5/6/2013 10:52:12 AM