Marine Ecosystems Research Department - jamstec japan agency ...

JAMSTEC 2002 Annual Report
Marine Ecosystems Research Department
populations directly and indirectly incorporate substances
ejected from the seafloor, and are thought to
contribute significantly to the circulation of these
ejected substances. Making use of deep-sea research
systems such as submersibles and ROVs, this
research aims to clarify the interrelationship between
substances ejected from within the earth and deep-sea
chemosynthetic ecosystems, and the basic physiological
and ecological characteristics of deep-sea
chemosynthetic populations.
From May to July , geochemical, microbiological
and zoological investigations were conducted using
the submersible 'Shinkai ' at a hydrothermal vent
field, the Hatoma Knoll in the Okinawa Trough, and a
methane seep field, the Kuroshima Knoll (Fig. ) off
Sakishima Islands. The purpose of this investigation
included; ) geochemical analysis of water at vent
communities and vent fluids, ) physical environmental
factor analysis at vent communities and vent fluids,
) estimation of energy sources for vent ecosystems,
) biodiversity of vent communities, ) estimation of
biomass of vent communities, ) estimation of productivity
of vent communities, ) relationships of biomass
and productivity between microbial communities and
benthic communities, ) comparisons between the
Kuroshima Knoll and the Hatoma Knoll, ) physiological
and embryological studies of vent benthic species.
Data and samples collected during the investigation
are now being analyzed.
Fig. 6 Bathymodiolus short-type dominated community associated
with methane seep in the Hatoma Knoll.
Research on the characteristics of the deep seawater
in Suruga Bay and the cascade method of deep
seawater utilization
Period: FY-FY
Shizuoka Prefecture is carrying out the project for
the effective utilization of deep seawater in Suruga
Bay. In September the Prefecture installed intake
facilities for surface water (depth of m) and deep
water (depths of m and m), and began distributing
the water to private companies and households.
The objectives of this research are to contribute to the
efficient promotion of the project, and to the establishment
of practical deep seawater utilization technology.
To this end, we are working together with Shizuoka
Prefecture to deploy analysis and observation systems,
research deep seawater near the Suruga Bay intake
and its surrounding area, and examine the cascade
method for the effective use of deep seawater.
The following are the major research results for
fiscal .
(a) Characteristics of deep seawater
In October we conducted surveys in and around
the deep seawater intake area using CTD and also
through vertical multilayer water sampling. Our use of
an altimeter in CTD observations enabled us to measure
down to five meters directly above the seafloor. In relation
to the issue of suspended matter, the vertical distribution
of the attenuation coefficient (Fig. ; high values
indicate high turbidity) calculated from a flux transmissometer
fitted to the CTD system tends to show a high
attenuation coefficient in water shallower than m and
water between a depth of m and the seafloor
(m). Similarly, the vertical distribution of suspended
matter concentration (Fig. ) in seawater collected in
the same cast as this measurement shows a high reading
in water shallower than m and water deeper than
m. Deep seawater intakes are established at depths
of m and m, and the opening that draws in seawater
is m above the seafloor. Therefore water with
relatively high concentrations of suspended matter is
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