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doi:10.2204/iodp.proc.336.110.2012

Results

The period covered for this report is 19 September–1 November 2011. Pearson’s product-moment correlation (SPSS) was utilized for statistical analyses. All data were normally distributed according to the Kolmogorov-Smirnov test.

Ship and atmospheric data

Ship heading (direction of bow) and cruising speed were recorded daily. During the period 19 September–1 November, the JOIDES Resolution was on site from 21 to 28 September and 2 October to 1 November. During these two periods, the bow was generally into the wind and pointing east. On 19 and 20 September and 29 September–1 October the JOIDES Resolution was in transit (avoiding the peripheral path effects of Tropical Storm Philippe), and the heading recordings taken each morning were 7°, 13°, 60°, 145°, and 275°, respectively. The only days where the orientation of the bow was far removed from east was 27 September (200°), 28 September (360°), and 11 and 12 October (185°). Atmospheric data comprising humidity, barometric pressure, temperature, wind speed, and wind direction were recorded each morning to coincide with the morning sample start times, and UV-340 and UVC-254 were recorded at the end of the low-volume A sample period (~1000–1100 h in most cases). Humidity ranged from 65.8% to 84.3% (average = 74.5%), barometric pressure ranged from 29.9 to 30.1 mm Hg (average = 30.0 mm Hg), temperature ranged from 25.4° to 30.1°C (average = 26.6°C), wind speed ranged from 0.7 to 13.5 m/s (average = 5.5 m/s; Fig. F1), UV-340 ranged from 33 to 316 µW/cm² (average = 161.2 µW/cm²; instrument set range = 2000–19990 × 10), and UVC-254 ranged from 0.037 to 0.439 mW/cm² (average = 0.296 mW/cm²; instrument set range = 1.999).

Particle counts

Particle counts were taken daily at a frequency of once every 10 min, with the exception of 27–29 September, when a faulty pump battery interfered with the AC adapter current flow. On 28 September, particle counts were obtained for the low-volume A sample period. For the purposes of charting, 27 September estimates were obtained by averaging the 26 and 30 September counts, the 28 September counts (except the low-volume A sample period) were obtained by averaging the acquired 27 September estimate and the 30 September counts, and the 29 September counts were obtained by averaging the acquired 28 September estimate and the 30 September counts. Particle counts for the sample periods were as follows: low-volume A samples ranged from 1.64 × 10⁶ to 9.63 × 10⁷ (average = 3.54 × 10⁷) particles/L³; low-volume B samples ranged from 2.63 × 10⁶ to 7.30 × 10⁷ (average = 3.02 × 10⁷) particles/L³; liquid impinger samples ranged from 5.20 × 10⁴ to 1.31 × 10⁸ (average = 3.92 × 10⁷) particles/L³; and high-volume samples ranged from 1.82 × 10⁶ to 5.17 × 10⁷ (average = 2.34 × 10⁷) particles/L³ (Fig. F2). In all cases, the highest concentrations of particles fell within the >0.3–0.5 µm size range (representing ~80%–90% of the total particle count).

High-volume membrane filtration samples

High-volume membrane filtration was used to collect airborne particulates each day, with the exception of the 29 October sample, when the pump brushes were serviced. The flow rate for each sample was 20 ft³/min. Samples were started daily between 0645 and 1215 h and were stopped the following morning between 0500 and 0715 h. Visual results are illustrated in Figures F3 and F4. These samples will be used for universal 16S and 18S rRNA qPCR to obtain total bacterial and fungal counts and analyses for particulate chemical composition. Filters were stored in cryogenic storage for shore-based analyses. Each filter was photographed by IODP-United States Implementing Organization (USIO) Senior Imaging Specialist Bill Crawford, and associated data were provided to IODP-USIO Applications Developer Algie Morgan for IODP cataloging.

Low-volume membrane filtration samples

Two low-volume samples were collected daily. Low-volume A was started in the morning and collected over a 4–6 h period, with flow rates ranging from 1.75 to 9.4 L/min. Low-volume B was a longer period sample that was collected throughout the day at a flow rate ranging from 3.5 to 9.4 L/min. Low-volume A bacterial and fungal CFUs ranged from 0 to 6.34 CFU/m³ and 0 to 4.87 CFU/m³ of air, respectively. The total CFU range was the same because bacteria and fungus were not detected simultaneously in any of these samples. For this sample set, bacteria and fungus were detected in 6 and 4 of the 44 samples, respectively. Low-volume B bacterial and fungal CFUs ranged from 0 to 0.55 CFU/m³ and 0 to 4.76 CFU/m³ of air, respectively. Total CFUs (bacteria and fungus) ranged from 0 to 4.76 CFU/m³ of air (Fig. F5). Total CFU and particulate counts were statistically correlated (r = 0.360, P = .017). For this sample set, bacteria and fungus were detected in 4 and 16 of the 44 samples, respectively. In total, they were detected in 18 of the 44 samples. For both low-volume samples, isolates were picked, cultured in TSB media, and stored in cryogenic storage for shore-based 16S and 18S sequence-based identification.

Liquid impinger samples

Liquid impinger samples were collected daily between 0500 and 1430 h over a period of 1–4 h. Sample volumes ranged from ~18 to 78 m^–3 of air. CFU, isolate identification, 16S and 18S qPCR, and significance to atmospheric particle counts will be evaluated on shore.

Surface water samples

Surface water samples were collected daily between 1110 and 1425 h. For the sample set, temperature ranged from 23.5° to 29.5°C (average = 27.1°C), pH ranged from 8.4 to 8.5 (average = 8.4), and refractometer salinity measurements ranged from 37.5 to 40 (average = 39.4). Bacterial and viruslike direct counts are illustrated in Figure F6. Bacterial counts ranged from 2.85 × 10⁵ to 4.82 × 10⁵ (average = 3.78  × 10⁵) counts/mL. Viruslike particle direct counts ranged from 1.45 × 10⁶ to 3.77 × 10⁶ (average = 2.50 × 10⁶) counts/mL. Bacterial and viruslike particle direct counts were significantly correlated (r = 0.384, P = .010). Bacterial counts were also significantly correlated with the high-volume time period (daily) atmospheric particle counts (r = 0.383, P = .010) (Fig. F7). Viruslike particle direct counts were not significantly correlated with the high-volume time period atmospheric particle counts. Culturable Vibrio spp. were detected on 28 September and 8 and 13 October at concentrations of 1.25 × 10⁴, 5.0 × 10², and 5.0 × 10² CFU/100 mL, respectively. The Vibrio colonies were picked, cultured in TSB media, and stored cryogenically for shore-based 16S identification. Daily aliquots of pelleted cells and of noncentrifuged surface water samples were stored in cryogenic storage for shore-based 16S universal and Vibrio spp. qPCR. These data will be used to test association hypothesis.

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