Sampling and Analysis
Summary of activities from the
EuroSTRATFORM experiment during 02-03
The first cruise occurred in October -November 02 on the
Spanish ship R/V Garcia del Cid. It involved the deployment
of tripods and moorings, and documented autumn
conditions for the water column and seabed.
The second cruise, which took place in February 03, was probably
the most difficult,
because we had to recover, refurbish, and redeploy all the
instruments and moorings, as well as document changes in the
water column and seabed. Several factors led to the success
of this cruise. The Seward Johnson II and crew were highly
capable of maneuvering for all operations, even in shallow
water and during winter conditions. This winter appears to
have been an exceptional year for large river discharge and
energetic oceanographic conditions. Despite some hits by fisherpeople,
almost all of our instruments were present and accounted for.
WATER-COLUMN WORK - Fast surveys (near synoptic) were undertaken
on a
small Italian ship, while instrument recovery/redeployment
and seabed sampling
were undertaken on the SJII. These included one full survey
along the Apennine rivers to the Po and two smaller surveys
along the Apennine coast, and recovered 109 CTD profiles and
67 "pogo" profiles (CTD and bottom-triggered Niskin
bottle).
Hydrographic surveys were undertaken in association with
the instrument recoveries/redeployments on the SJII. These
included 107 "gafanhoto" profiles (CTD, OBS, transmissometer,
current speed/direction, water samples).
Fast surveys (near synoptic) were undertaken on the SJII
at the end of instrument recoveries and redeployments. These
included one full survey along the Apennine rivers to the
Po and three smaller surveys along the Apennine coast, and
recovered 183 CTD profiles and 164 "pogo" profiles.
Ten of these profiles were used to cross-calibrate the CTD,
"pogo" and "gafanhoto" instrumentation.
At 85 stations, water samples were
Filtered for measurement of suspended organic materials.
TRIPOD/MOORING OPERATIONS - A total of 10 boundary-layer systems
were
deployed on the shelf, usually in across-shelf couplets at
~10 m and ~20m water depth. At most sites two guard buoys
were deployed (16 total). At all sites, one of the guard buoys
included a SeaCat system (salinity/temperature), mounted for
measurement of surface plumes. One fully instrumented mooring
was deployed on the Apennine clinoform foresets to monitor
impacts of internal waves.
Five tripods were deployed at and southward of the Po River.
Four were recovered with 90-days worth of data (including
various assortments of: ADV, ABS, OBS, transmissometers, CTD,
pressure, EMCM, upward-looking ADCP, and a video floc-settling
camera). One tripod was knocked on its side, but the new geometry
was noted and data can still be used. The fifth tripod was
a small system that apparently is buried within the mud; divers
detected its homing beacon, but could not
find it.
Three tripods were deployed off the Chienti River on the
Apennine coast. Three-month records were recovered for most
instrumentation (ADV, ADP, CTD, OBS, transmissometer, pressure,
ABS, LISST, video camera, and upward-looking ADCP). Partial
records were recovered of sonar images and microphotographs
("poking eyeball"). [Two days before recovery, one
tripod was knocked on its side.]
Two tripods and the instrumented mooring were deployed off
the Pescara River on the Apennine coast. One tripod recovered
three-month records (ADV, OBS, transmissometer, CTD, pressure,
EMCM, upward-looking ADCP, and video floc-settling camera).
The second tripod was knocked over by fisherpeople and recovered
1.5 months of good data. The instrumented mooring recovered
data for all three months (6 temperature sensors, 2 RCM9 current
meters/transmissometers).
Between recovery and redeployment at the Po, Chienti, and
Pescara sites, a specialized boundary-layer system (INSECCT)
was deployed for four periods of 1.5-2.5 days, and measured
current speed/direction and associated floc size (photos,
video), settling velocity, and recovered flocs in polyacrylamide
gel cups.
All but one of the SeaCats were recovered, and all appeared
to have recorded data.
Despite some dings from fisherpeople and biofouling of instrumentation
(severe in some cases), almost all sensors could be redeployed
for recovery in May-June.
SEABED CORING - Sediment cores were collected near the following
rivers: Po,
Metauro, Chienti, Pescara, Biferno. A total of 53 box cores,
58 hydraulically dampened "slow" cores, and 6 kasten
cores were collected. These were examined by digital x-radiography,
a resistivity probe, and were subsampled for laboratory measurements
of Pb-210, Be-7, Th-234, grain size, carbonate content, water
content, and organic content (%C, C stable isotopes, C/N ratios).
At 10 stations, "slow" cores were studied (~25
Cores total) in an erosion chamber, which applied variable
shear stresses between
0.01-0.4 N/square m and measured turbidity released.
The third cruise is scheduled for 22 May - 11 June, at which
time all instruments will be recovered and spring conditions
will be documented for the water column and seabed.
The work described below was undertaken by scientists from:
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