Table T1. Characteristics of tracers injected during 24 h pumping experiment, Expedition 327. (See table notes.)
| Tracer | Quantity |
Injection duration |
Mean injectate concentration |
Concentration in bottom seawater* |
Detection limit |
Dilution factor |
|---|---|---|---|---|---|---|
| SF6 |
3.40 kg 23.3 mol |
20.22 h | 47.6 µM | ND | 0.07 pM | ~7 × 108 |
| Cs (as CsCl) |
2 × 15 kg 2 × 89.1 mol |
7.5 min 8 min |
18.0 mM 15.6 mM |
2.2 nM | 0.1 nM |
~8 × 106 ~7 × 106 |
| Er (as ErCl3·6H2O) |
23 kg 60.3 mol |
7.5 min | 12.2 mM | 9.6 pM | 0.1 nM | ~1 × 109 |
| Ho (as HoCl3·6H2O) |
23 kg 60.6 mol |
8 min | 10.6 mM | 2.7 pM | 0.02 pM | ~3 × 109 |
| BB Coumarin, 1.0 µm† | 4.5 × 1012 spheres | 6 min | 2 × 106 spheres/mL | ND | 1/mL | ~2 × 106 |
| YG Fluorescein, 1.1 µm† | 2.3 × 1013 spheres | 6 min | 1 × 107 spheres/mL | ND | 1/mL | ~1 × 107 |
| BB Coumarin, 0.49 µm† | 3.6 × 1013 spheres | 6 min | 2 × 107 spheres/mL | ND | 1/mL | ~2 × 107 |
| DAPI-stained cells | 1011 cells | 8 min | ~104 cells/mL | ND | 1/mL | ~104 |
| Freshwater (chlorinity) | 48,000 L total | 2 h | 0 mmol/kg | 542 mmol/kg | 1 mmol/kg | ~5 × 102 |
Notes: * = SF6, fluorescent microspheres, and fluorescent-stained microbes are entirely anthropogenic and so would not be detected in the bottom water of the northeastern Pacific Ocean except where introduced. Bottom water concentrations for trace metals from this area are from Hulme et al. (2008) and Wheat et al. (2010). Detection limits for SF6 are from Clark et al. (2005) and those for trace metals are from Hulme et al. (2008). Detection limits for fluorescent microspheres and stained microbes could be greater than indicated but will depend on fluid particle concentrations and visibility following filtering of samples. † = trade name of fluorescent dye and mean sphere diameter. Tracer: SF6 was injected as a dissolved gas through most of pumping test. CsCl + ErCl3·6H2O and CsCl + HoCl3·6H2O were injected as solutions in seawater during two brief periods. Fluorescent microspheres were injected in suspension in freshwater during a brief period. Fluorescent-stained bacteria were injected in suspension in seawater during a brief period. Mean injectate concentrations are estimated based on known quantities added and total rates of injectate pumping with mud pumps and cement pumps. Actual injectate concentrations will be determined as part of postexpedition analyses of samples collected on the rig floor and at the end of the stinger in the open hole. Dilution factors are calculated as (mean injectate concentration)/(detection limit) for SF6, fluorescent particles, and freshwater and as (mean injectate concentration)/(concentration in bottom seawater) for trace metals. Estimated DAPI-stained cell numbers are based on regional surveys of bacterial concentrations in surface seawater (e.g., Sherr et al., 2001). ND = not detected.
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