Fig 1.
Experimental setup and exposure characteristics.
A, antivibration bench with 2 replicate tanks on it; B, complete scheme of a unit; C, inside view of an experimental tank. 1, sand; 2, frame angle structure; 3, chipboard panel; 4, air chambers; 5, concrete slab; 6, tennis ball; 7, pieces of thermal insulation; 8, oysters equipped for behavioral recordings; 9, oysters for tissue sampling; 10, electrode cables; 11, hemstitched support; 12, loudspeaker. D, 72 h of sound recording. Each vertical bar is the noise from one passing cargo ship. Black bands represent periodic absence of cargo ship noise. E: the change of cadmium concentration in the 4 tanks as a function of time. There were 2 antivibration benches and 2 replicate tanks per bench.
Table 1.
Primers used for the RT-qPCR assay.
Fig 2.
The change of cadmium concentration in the gills (A, A1) and digestive glands (B, B1) in oysters M. gigas. A: mean values ± 1 SE as a function of time in the gills; B, in the digestive glands. A1 and B1, Distribution of probability densities at day 0 (T0), day 3 (T3), day 7 (T7) and day 14 (T14). In the presence of cargo ship noise, the distributions were skewed to the lower values at T3, T7, and T14 in the gills and T14 in the digestive glands.
Fig 3.
Behavioral changes in the presence of cargo ship noise in oysters M. gigas exposed to Cd.
A, Distribution of individual valve closure durations. B1, Description by quartiles of the hourly valve closure durations during the light (7-18h) and B2, dark (18-7h) periods in oysters exposed to Cd plus cargo ship noise (white) or Cd alone (gray). D, number of partial valve closures per hour. A, B1, B2, and D were calculated for the whole 14-day-exposure period; bold lines, medians. With one exception at the bottom of Fig 1A, the variability was systematically lower in the presence of cargo ship noise. C, Valve opening—closing actograms, each line represents 1 day. The white and black sections of each line represent hourly behavioral values above and below the mean behavior of the day, respectively. In the presence of cargo ship noise, the oysters are closed more during the day (light) period, gray area. The black arrows show the daily timing of the food supply, just prior the opening behavior associated with the automatic light shut-off. N = 13 oysters exposed to Cd and cargo ship noise and 12 oysters exposed to Cd alone.
Fig 4.
Transcriptional variations of selected genes in the gills of oysters M. gigas exposed to Cd plus cargo ship noise or Cd alone for 14 days.
* and ** denote significant differences between the condition and the control and between experimental conditions, respectively.
Fig 5.
Distribution of the probability densities of gene expression in three genes exhibiting a different variance at day 14.
In the presence of cargo ship noise (Cd + N), the distributions were skewed to the lower values in comparison to the distribution in the absence of the ship noise (Cd).
Table 2.
Pearson correlation of [Cd]g and gene expression in Cd and Cd+N conditions.
Fig 6.
Growth rate index in oysters M. gigas in the presence of cadmium with (Cd + N) or without (Cd) cargo ship noise.
A, daily change of growth rate index. B, description by quartiles of the difference between growth index at day 14. The growth rate is smaller in presence of cargo ship noise. N = 13 oysters exposed to Cd and cargo ship noise and 12 oysters exposed to Cd alone.