Behavioral response of Corophium volutator relative to experimental conditions, physical and chemical disturbances

Abstract

The preference/avoidance behavioral response of a widely used amphipod in toxicity tests, Corophium volutator, was investigated in relation to the presence of anthropogenic physical or chemical materials in sediments. Exposure conditions, including the density of amphipods, the depth of sediments, amount of overlying water, and exposure time, were examined for their influence on amphipods' preference for field sediments and avoidance of coarse sand. It was shown that these variables did not affect the response; thus, conditions similar to published standard toxicity tests were chosen. A gradient of sediments spiked with potential habitat disturbances that can be found on a beach or in contaminated sediments, such as those in harbors, were tested. These substances included sand, seaweed, burned wood, coal, crankcase oil, and diesel oil. To enhance the interpretation of results and decrease the variability observed when tests were conducted at different times over the summer, exposures were performed over a gradient of spike material in reference sediments. We conclude that physical obstacles added to reference sediments lead to less correlation with the behavioral response than observed with chemical interferences. Amphipods' behavior ranked harbor sediments similarly to previous studies concerning the health of intertidal mussels collected in proximity to the sediments sites. For five sites, preference of reference sediments was observed until the level of polycyclic aromatic hydrocarbons in diluted harbor sediments reached the Canadian Council of Ministers of the Environment sediment quality guidelines.

Behavioural ecotoxicology, an “early warning” signal to assess environmental quality

“…This was also reported by Kravitz et al (1999). Amphipods always survived (>80%) if fed 2 days before being placed on contaminated harbour sediments for 10 days (Hellou et al 2005). It was also discovered fortuitously that if the feeding of the animals was omitted the Friday prior to the Monday exposure, the animals would perish.…”

Comparison of the partitioning of pesticides relative to the survival and behaviour of exposed amphipods

“…Amphipods and sediments were collected during the summer, from two beaches in the Bay of Fundy, Hantsport and Avonport, Nova Scotia, Canada, during low tide where they could be easily seen in sediments (Hellou et al 2005). Trowels were used to scoop surface sediments with visible animals into buckets that were filled half way and topped with 2-5 cm of seawater, prior to transportation to the laboratory, within 1-2 h. Collected sediments were then sieved over 0.5 mm mesh and 2,000-3,000 amphipods were placed in 20 l tanks containing 1-2 cm of the same sediments, with half the tank filled with seawater.…”

“…animals were started once on the reference side, once on the spiked side of two identical tanks containing reference and contaminated sediments (Hellou et al 2005). In year 2, experiments were modified to produce identical duplicate exposures for each tested concentration and pesticide by placing the animals in the middle of the water layer covering the sediments.…”

“…indicates a preference for reference sediments. Number in parenthesis and bold for higher statistical significance (p \ 0.001 compared to 0.05) c Represents 48-96 h exposures (Kamrin 1997) Comparison of the partitioning of pesticides 31 between duplicate exposures (Hellou et al 2005). Nearly 75, 95 and 100% of the harbour results displayed B10%, B20% and B30% difference between duplicates.…”

“…Recently, the behavioural response of C. volutator towards contaminated field sediments was used in our laboratory to compare the bioavailability of harbour contaminants (Hellou et al 2005(Hellou et al , 2008. Concentrations of abundant organic priority pollutants, polycyclic aromatic hydrocarbons corresponding to the Canadian Council of Ministers of the Environment sediment quality guidelines were associated with levels initiating the amphipods' avoidance of harbour sediments.…”