Minerals Report - International Seabed Authority

search for sites of hydrothermal venting. Since methane is also emitted at
faults, and by hydrothermal alteration (serpentinization), Dr. Herzig stressed
the need for a correlation between manganese and methane. He used an
example from the Indian Ocean to highlight the need.
In addition to these two elements, Dr. Herzig said that isotopes such as
helium are also good pathfinder elements. However, while manganese and
methane can be analyzed on the vessel, helium and the other isotopes have to
be analyzed in a land-based laboratory.
Dr. Herzig said that temperature anomalies are also used in the search.
The towed CTD devices are excellent for this purpose he said, because very
little time is wasted lowering and raising the system.
Dr. Herzig said that recently, geochemical scanners have been
developed and are being used. He showed participants pictures of two such
systems, the ZAPS system that was developed by Oregon State University,
and the SAUVE system that was developed by the United States NOAA. Dr.
Herzig said that ZAPS is towed by the vessel and is able to record the density
of metal particles from black smokers in the water column. The SUAVE
system, also towed by the research vessel, was presented by Dr Herzig and
shown mounted on a video camera system. Dr. Herzig said that the SUAVE
system could analyse Fe 2+ , Fe 3+ , Manganese and Hydrogen sulphide (H2S). He
said that the data obtained by this system are stored on a recorder within the
instrument, retrieved later, and correlated with time. Dr. Herzig said that
time on the vessel is positioned, so when correlated with position, researchers
are able to go back to areas where anomalies have been identified.
Dr. Herzig said that both systems could be equipped with a CTD
system. He also said that both systems could analyse the concentration of
manganese photo-chemically and also measure bio-phosphorescence. The
data collected by the system are stored on a recorder, and subsequently
related to the vessel’s position. He said that an obvious advantage of this
system is the large area that it could cover. He described the system as a time
saving method of acquiring the relevant information.
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