University of Bordeaux, EPOC, Arcachon, France.
CNRS, EPOC, Talence, France.
PLoS One. 2018 Apr 4;13(4):e0194174. doi: 10.1371/journal.pone.0194174. eCollection 2018.
Shipping has increased dramatically in recent decades and oysters can hear them. We studied the interaction between noise pollution and trace metal contamination in the oyster Magallana gigas. Four oyster-groups were studied during a 14-day exposure period. Two were exposed to cadmium in the presence of cargo ship-noise ([Cd++]w ≈ 0.5 μg∙L-1; maximum sound pressure level 150 dBrms re 1 μPa), and 2 were exposed only to cadmium. The Cd concentration in the gills ([Cd]g) and the digestive gland ([Cd]dg), the valve closure duration, number of valve closures and circadian distribution of opening and closure, the daily shell growth-rate and the expression of 19 genes in the gills were studied. Oysters exposed to Cd in the presence of cargo ship-noise accumulated 2.5 times less Cd in their gills than did the controls without ship noise and their growth rate was 2.6 times slower. In the presence of ship noise, oysters were closed more during the daytime, and their daily valve activity was reduced. Changes in gene activity in the gills were observed in 7 genes when the Cd was associated with the ship noise. In the absence of ship noise, a change in expression was measured in 4 genes. We conclude that chronic exposure to cargo ship noise has a depressant effect on the activity in oysters, including on the volume of the water flowing over their gills (Vw). In turn, a decrease in the Vw and valve-opening duration limited metal exposure and uptake by the gills but also limited food uptake. This latter conclusion would explain the slowing observed in the fat metabolism and growth rate. Thus, we propose that cargo ship noise exposure could protect against metal bioaccumulation and affect the growth rate. This latter conclusion points towards a potential risk in terms of ecosystem productivity.
航运在最近几十年大幅增长，而牡蛎可以听到这些声音。我们研究了牡蛎 Magallana gigas 中噪声污染与痕量金属污染之间的相互作用。在 14 天的暴露期内，研究了四个牡蛎组。两组暴露于载有货物的船舶噪声中的镉（[Cd++]w≈0.5μg·L-1；最大声压级 150dBrms re 1μPa），两组仅暴露于镉。研究了鳃（[Cd]g）和消化腺（[Cd]dg）中的镉浓度、阀关闭持续时间、阀关闭次数、开闭的昼夜节律分布、日贝壳生长率以及鳃中 19 个基因的表达。与没有船舶噪声的对照组相比，在载有货物的船舶噪声中暴露于镉的牡蛎在鳃中的镉积累量减少了 2.5 倍，其生长速度降低了 2.6 倍。在船舶噪声的存在下，牡蛎在白天关闭的次数更多，每日阀活动减少。当 Cd 与船舶噪声相关联时，观察到鳃中 7 个基因的活性发生变化。在没有船舶噪声的情况下，有 4 个基因的表达发生变化。我们得出结论，慢性暴露于货船噪声会对牡蛎的活动产生抑制作用，包括对水流过鳃的体积（Vw）的影响。反过来，Vw 和阀开启持续时间的减少限制了金属对鳃的暴露和吸收，但也限制了食物的吸收。后一种结论可以解释所观察到的脂肪代谢和生长速度的减缓。因此，我们提出货物船舶噪声暴露可能会防止金属生物累积并影响生长速度。后一种结论表明，在生态系统生产力方面存在潜在风险。
