Traps were suspended from each of the buoys:
- CENTRE: 20 m
- IN: 40, 60, 100, 200 m
- OUT: 20, 40, 60 and 100 m
Traps were recovered several times.
Deployment times (days):
- CENTRE: 3.95, 2.83, 2.02, 1.98, 1.93, 2.05
- IN: 3.99, 2.84, 2.03, 2.00, 1.95, 2.01
- OUT: 5.17, 3.97, 3.42
Notes from original xls file: Sinking_particles.xls
Drifting sediment trap experiment by CREST/NIES
(dm) 105 lines of comments before data begins.
(dm) all comments except 7 lines prefaced with (dm) are copied from original file.
Comments (dm) by fcsv file compiler
(dm) NOTE that I traps 200m data collected with different style (Aono type trap)
Cylindrical sediment trap of Knauer design was used.
Eight traps deployed on each cross-frame.
The cylindrical trap is separable into upper cylinder and bottom cup.
The upper cylinder has a baffle at the open end. (see picture)
(DMO Note: No picture enclosed)
- All the traps was filled with a high density gradient solution(approximately 39 permil containing 2 % formalin).
- The solution was prepared with filtered seawater sampled nearbystation of the Fe infusion and NaCl was added.
- At the deployment of the trap half volume of the high density solution might be replaced with surrounding seawater.
- Center drifter was deployed to locate the center of Fe patch which had 20 m depth trap positioning buoys radar reflector and drogue.
- Inside drifter was deployed at the distance of 0.3 mile from the center drifter which had 40 60 100 and 200 m depth traps positioning buoys and radar reflector.
- Outside drifter was deployed at the distance of 20 mile from the center drifter which had 20 40 60 and 100 m depth traps positioning buoys and radar reflector.
- Trap design of 200 m depth was different (0.16 m in diameter and 4 traps on a frame).
- The detail of the design is described in Th234 data set file.
20 m trap sample of center drifter in Run 2 was lost by an accidental event at deck recovery.
20 m trap of center drifter in Run 4 was lost because of the breakage of hydro wire.
Recovered sample in the bottom cup was transferred into 500 mL polystyrene bottle.
Formalin was added at final concentration of 5 % for preservation until on shore analysis.
The folmalin used was neutralized with sodium borate (Borax).
Large zooplankton (swimmer was removed under microscope.
Regular design traps (Knauer Type)
- 2-3: Nuclepore for biogenic Si analysis
- 4: Nuclepore for metallic element analysis
- 5: Nuclepore for spare
- 6: GF/F for C N analysis by Carlo Erba elemental analyzer (EA1110)
- 7: GF/F for C13 analysis of organic carbon by Delta Plus (Finnigan MAT combined with the Carlo Erba elemental analyzer)
- 8: GF/F for spare
Size of the filters were 47mm in diameter and pore size of Nuclepore filter was 0.6 micro meter.
Pre-weighted filter was used for filtration.
The pre-weighting procedure was identical to the sample weighting.
Filter with trapped material was immediately frozen in -30 degree C freezer.
Filters were dried in a vacuum freeze dryer.
After drying the filter it was kept in a clean balance room controlled at 23 degree C and 50 % humidity.
The reproducibility of the weight measurement was 0.05 mg for each filter.
Total mass flux was calculated from 4 replicate measurement of Nuclepore filters.
The weight of GF/F samples were also measured however the stability of the weight
was poorer than that of Nuclepore filter.
For C/N analysis GF/F filter was fumed in a desiccator containing conc.
HCl to vaporize the inorganic carbon.
Trap dimensions:
- Length (L) m 0.63
- Inside diameter (Di) m 0.07
- Outside diameter (Do) m 0.075
- Aspect ratio (AR) 8.86
- Collection area (A) m2 0.00385
- Trap volume (V) m3 0.00239
- Trap volume (V) litres 2.386
- Baffle length (Lb) m 0.076
- Baffle diameter (Dib) m 0.013
- Baffle aspect ratio (ARb) 5.85
Aono type trap (used I traps at 200 m only collection area 0.020106 m2
Trap collection area 0.003848 m2
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