Morin Soizic, Duong Thi Thuy, Herlory Olivier, Feurtet-Mazel Agnès, Coste Michel
Cemagref, UR REQE, 50 av. de Verdun, Cestas Cedex, France,
Arch Environ Contam Toxicol. 2008 Feb;54(2):173-86. doi: 10.1007/s00244-007-9022-4. Epub 2007 Sep 1.
A microcosm study was undertaken to examine the effects of dissolved cadmium at various concentrations (0, 10, and 100 microg . L(-1)) on biofilm accumulation and diatom assemblages. A natural biofilm sampled from the Riou-Mort River (Southwest France) was inoculated into three experimental systems, where biofilm settled on glass slides. Samples collected after 1, 2, 4, and 6 weeks of colonization were analyzed for metal accumulation (total metal content and intracellular metal content in the biofilm), biomass (as measured through dry weight and ash-free dry matter), and quantitative as well as qualitative analysis of diatom assemblages. There was a positive correlation between cadmium accumulation and dissolved cadmium concentrations and duration of exposure: a linear relationship was found between concentration factors (CFs) of growing biofilms and time (CFs/day = 0.25 and 0.38 under contaminations of 10 and 100 microgCd . L(-1), respectively). Biofilm settlement, more than photosynthetic activity, was affected by high cadmium concentrations: we observed for all stages of settlement a drastic and significant (p < 0.05) reduction in biofilm biomass and in diatom densities in the highest cadmium contamination, compared to control and low cadmium concentration units.
开展了一项微观世界研究，以考察不同浓度（0、10和100微克·升⁻¹）的溶解镉对生物膜积累和硅藻组合的影响。从法国西南部的里奥莫尔特河采集的天然生物膜被接种到三个实验系统中，生物膜附着在载玻片上。在定殖1、2、4和6周后收集的样本，用于分析金属积累（生物膜中的总金属含量和细胞内金属含量）、生物量（通过干重和无灰干物质测量）以及硅藻组合的定量和定性分析。镉积累与溶解镉浓度和暴露持续时间之间存在正相关：在生长生物膜的浓度因子（CFs）与时间之间发现了线性关系（在10和100微克镉·升⁻¹的污染条件下，CFs/天分别为0.25和0.38）。高镉浓度对生物膜沉降的影响大于对光合活性的影响：与对照和低镉浓度单元相比，在最高镉污染条件下，我们观察到在生物膜沉降的所有阶段，生物膜生物量和硅藻密度都急剧且显著（p < 0.05）降低。
