Detecting copper toxicity in sediments: from the sub-individual level to the population level

1.Sediments accumulate chemicals that can be toxic to biota and often contribute to aquatic ecosystem decline. Measuring mortality in laboratory-bred organisms is a common way to assess sediment toxicity. However, mortality-based responses of resilient laboratory organisms may not reflect indigenous macroinvertebrate responses, which can be relatively more sensitive to sediment toxicants. A possible solution is to also measure responses at the sub-individual level.

2.Several organism responses to sediment copper toxicity were assessed in a field-based microcosm. Responses of laboratory-bred chironomids and snails deployed in microcosms were compared at sub-individual (metabolomic and gene expression), individual (survival and dry weight) and population (reproduction) levels, and contrasted to the abundance of colonizing macroinvertebrates in the microcosms.

3.Colonizing macroinvertebrate abundance showed a range of sensitivities based on EC50 (effect dose 50% change). Chironomidae...