02266nas a2200289   4500008004100000022001400041245012200055210006900177260000800246300001300254490000800267520139100275653001201666653001301678653002401691653002301715653002601738653001301764653002701777100002001804700001601824700001901840700002501859700002001884700002401904856004801928       2011                        eng d  a1559-072000a{An assessment of the impact of chromium-amended sediment on a marine nematode assemblage using microcosm bioassays.}0 aassessment of the impact of chromiumamended sediment on a marine  caug  a242–550 v1423 aMicrocosms were used to assess the impact of chromium on free-living marine nematodes. Nematodes were exposed to three chromium concentrations (500 ppm (dm, dry mass), 800 ppm (dm) and 1,300 ppm (dm)), and effects were examined after 4 weeks. Results showed significant differences between univariate measures of control nematodes and those from medium- and high-chromium microcosms. Most, decreased significantly with increasing level of chromium contamination. The medium-chromium treatment seems to be the minimal concentration that could has a negative effect on nematodes. Results from multivariate analyses demonstrated that responses of nematode species to chromium treatments were varied: Leptonemella aphanothecae was eliminated at all doses tested and seemed to be intolerant species to chromium; Daptonema normandicum and Sabatieria longisetosa which significantly increased at 500 ppm chromium (dm) appeared to be "opportunistic" species at this dose whereas the two Bathylaimus species (Bathylaimus capacosus and Bathylaimus tenuicaudatus) which increased at all the doses tested seemed to be "chromium resistant". As we think such "opportunistic" and "resistant" species could be used as sensitive indicators of unsafe marine food. The use of microcosms has allowed the effects of the chromium on nematodes to be assessed individually, which was not possible in the field.10aAnimals10aChromium10aChromium: chemistry10aGeologic Sediments10aMultivariate Analysis10aNematoda10aNematoda: drug effects1 aBoufahja, Fehmi1 aHedfi, Amor1 aAmorri, Jalila1 aA{\"ı}ssa, Patricia1 aBeyrem, Hamouda1 aMahmoudi, Ezzeddine  uhttp://www.ncbi.nlm.nih.gov/pubmed/20632126