UMR 9190 MARBEC IRD-Ifremer-CNRS-Université de Montpellier, Place Eugène Bataillon, Case 093, 34095 Montpellier Cedex 5, France; Faculté des Sciences de Bizerte, Université de Carthage, 7021 Zarzouna, Tunisia.
UMR 9190 MARBEC IRD-Ifremer-CNRS-Université de Montpellier, Place Eugène Bataillon, Case 093, 34095 Montpellier Cedex 5, France; Faculté des Sciences de Bizerte, Université de Carthage, 7021 Zarzouna, Tunisia.
Chemosphere. 2016 Feb;144:1060-73. doi: 10.1016/j.chemosphere.2015.09.093. Epub 2015 Oct 23.
Contamination of coastal environments is often due to a complex mixture of pollutants, sometimes in trace levels, that may have significant effects on diversity and function of organisms. The aim of this study was to evaluate the short-term dynamics of bacterioplankton exposed to natural and artificial mixtures of contaminants. Bacterial communities from a southwestern Mediterranean ecosystem, lagoon and the bay (offshore) of Bizerte were exposed to i) elutriate from resuspension of contaminated sediment, and ii) an artificial mixture of metals and herbicides mimicking the contamination observed during sediment resuspension. Elutriate incubation as well as artificial spiking induced strong enrichments in nutrients (up to 18 times), metals (up to six times) and herbicides (up to 20 times) relative to the in situ concentrations in the offshore station, whereas the increases in contaminants were less marked in the lagoon station. In the offshore waters, the artificial mixture of pollutants provoked a strong inhibition of bacterial abundance, production and respiration and significant modifications of the potential functional diversity of bacterioplankton with a strong decrease of the carbohydrate utilization. In contrast, incubation with elutriate resulted in a stimulation of bacterial activities and abundances, suggesting that the toxic effects of pollutants were modified by the increase in nutrient and DOM concentrations due to the sediment resuspension. The effects of elutriate and the artificial mixture of pollutants on bacterial dynamics and the functional diversity were less marked in the lagoon waters, than in offshore waters, suggesting a relative tolerance of lagoon bacteria against contaminants.
沿海环境的污染通常是由于污染物的复杂混合物造成的，有时污染物的浓度很低，但它们可能对生物的多样性和功能产生重大影响。本研究旨在评估暴露于自然和人工混合污染物的浮游细菌的短期动态。来自西南地中海生态系统、泻湖和比塞大湾（近海）的细菌群落分别暴露于：i）受污染沉积物再悬浮产生的底泥淋溶物；ii）一种模拟沉积物再悬浮过程中观察到的污染的金属和除草剂人工混合物。与近海站的原位浓度相比，底泥淋溶物孵育以及人工添加污染物均强烈富集了营养物质（高达 18 倍）、金属（高达 6 倍）和除草剂（高达 20 倍），而在泻湖站，污染物的增加则不那么显著。在近海海域，人工混合污染物强烈抑制了细菌的丰度、生产力和呼吸作用，并显著改变了浮游细菌的潜在功能多样性，碳水化合物的利用明显减少。相比之下，底泥淋溶物的孵育则刺激了细菌的活性和丰度，表明由于沉积物再悬浮导致营养物质和 DOM 浓度增加，污染物的毒性效应发生了变化。与近海水域相比，底泥淋溶物和人工混合污染物对细菌动态和功能多样性的影响在泻湖水域较小，这表明泻湖细菌对污染物具有相对的耐受性。
