Marine Ecosystems Research Department - jamstec japan agency ...

Japan Marine Science and Technology Center
Research Activities
Mutsu Research Group
Research project; Category 1
1. Time-series observational study in the North
Pacific (HiLATS project)
(1) Overview
The importance of time-series observation has been
recognized for the better understanding of the ocean's
role in the uptake of the increasing atmospheric carbon
dioxide. However repeatable observation by ordinary
research vessels is indeed difficult both economically
and physically. Although the time-series sediment
trap experiment has been one of the effective
approaches for time-series observation, this instrument
is usually moored in the deep sea and does not always
give us the information about seasonal and interannual
variability in biogeochemistry in the upper ocean.
In order to clarify the "biological pump" more precisely,
time-series observation in the shallow and
intermediate water is essential using autonomous
observation instruments. Under this situation, the
North Pacific Time-Series Observational Study
(HiLATS project) initiated in as a research programs
at Mutsu Institute for Oceanography (MIO) of
JAMSTEC. This is also a joint program with the Joint
Pacific Research Center (JPAC) of the Woods Hole
Oceanographic Institution (WHOI).
(2) Outline of research activity
Fiscal years / and / were devoted
to the preparation of time-series instruments such
as automated incubation chamber, automated oceanographic
sampler and CTD profiler. In , the first
set of moorings were deployed in the northwestern
North Pacific. In / fiscal year, the first mooring
systems and data set were recovered.
(3) 2002/2003 annual report (HiLATS)
In the R/V MIRAI MR-K cruise conducted from
October to November , time-series mooring systems
(two moorings for biogeochemistry: BGC mooring,
one for physical oceanography: PO mooring; Fig.
) deployed at stations K and K (Fig. ) in September
were successfully recovered. In this cruise, a pair
of BGC mooring and PO mooring was also deployed at
stations K, K and K. In order to study material cycle
in the mesopelagic layer or "twilight zone", ten sediment
traps were installed on K BGC mooring (MEX
mooring; Fig. ). These mooring systems will be recovered
in September using R/V KAIREI.
Fig. shows seasonal variability in concentrations
of nutrients (silicate and nitrate/nitrite) at a depth of
around m observed using the automated water sam-
55˚N
50˚N
K1
45˚N
K2
40˚N
K3
35˚N
SeaWiFS Chl-a map (May 2002)
(Courtesy of Dr. Sasaoka of NASDA)
30˚N
140˚E 145˚E 150˚E 155˚E 160˚E 165˚E 170˚E
Fig. 1 Time-series stationsK1: 51N165E, K2: 47N160E, K3: 39N160E
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