Development and application of a rapid amphipod reproduction test for sediment‐quality assessment

Abstract

Melita plumulosa is an epibenthic, detritivorous amphipod native to eastern Australia that has been adopted as a test organism for toxicity evaluations of contaminated estuarine sediments. In the present study, a 13-d amphipod reproduction test was developed that encompasses gametogenesis, fertilization, and embryo development before hatching. The primary endpoints for the test are fecundity (measured as the number of embryos per individual surviving female) and a fecundity index (fecundity multiplied by the stage of embryo development). This new test has been employed to scrutinize the sediments from a metal-contaminated coastal lagoon. Lake Macquarie (NSW, Australia) is a large, saltwater lagoon that has received metal pollution over many decades, leading to a concentration gradient of trace metals, including Pb, Zn, Cd, and Cu, in the sediments. Within one of the northern bays (Warners Bay), the concentrations of these metals either border on or exceed sediment quality guideline values prescribed by Australian and New Zealand Guidelines for Fresh and Marine Water Quality. In trials with the 13-d amphipod reproduction test, Warners Bay sediments significantly reduced fecundity in the test species. Subsequent tests with clean sediments spiked singly with Pb, Zn, or Cu indicated that no single metal was responsible for the observed toxicity in the field sediments. However, sediments spiked with various combinations of Pb, Zn, Cd, and Cu indicated that Zn in combination with one or more of the other metals was responsible for the reproductive toxicity observed in Warners Bay sediments. In all these tests, measured metal concentrations in overlying water and pore water were low, thus confirming that the observed effects on reproduction could be attributed to dietary exposure to metals.

The influence of sediment particle size and organic carbon on toxicity of copper to benthic invertebrates in oxic/suboxic surface sediments

“…However, for such models to be appropriately implemented, further research is also required to determine the usefulness of a combined particle-size and OC normalization procedure for predicting chronic effects [45].…”

Review of the reproductive biology of amphipods and their endocrine regulation: Identification of mechanistic pathways for reproductive toxicants

“…Species survival depends ultimately on the reproductive success and quality of offspring; thus, reproductive variables are sometimes considered more predictive indicators of toxicological effects at population and community levels that may be occurring at more slightly impacted sites in the field [14]. Sublethal endpoints in laboratory-based sediment toxicity tests using amphipods have been found to be more sensitive to low concentrations of contaminants approaching the sediment quality guideline trigger values [15][16][17][18][19].…”

It’s All in the Genes: How Genotype Can Impact Upon Response to Contaminant Exposure and the Implications for Biomonitoring in Aquatic Systems

“…A second disadvantage of M. plumulosa is the variability in female fecundity . Female fecundity is a commonly assessed organismal endpoint of toxicant exposure in M. plumulosa, and is closely linked with dietary fatty acid composition which is crucial to ovary maturation and embryo development in amphipods and other crustacea (Clarke et al, 1985;Hyne et al, 2009;Middleditch et al, 1980). Recently, fine-milled silica has been shown to be a feasible alternative standardised substrate for short term toxicity tests; however, field collected sediments are still necessary for both long term tests and laboratory culture maintenance (Mann et al, 2011).…”

“…These include a 42-day (full life-cycle) chronic whole-sediment test using metal-spiked sediments , a 10-day acute whole-sediment test using both adult and juvenile animals and metal-spiked sediments (King et al, 2006b), and more recently a 13-day reproduction test using both laboratory cultured amphipods as well as in situ testing (Mann et al, 2009(Mann et al, , 2010(Mann et al, , 2011. In all cases genetically heterogeneous amphipods were employed, with large numbers of individuals needed to offset the potential effects of inter-individual variation in toxicant response.…”

“…In all cases genetically heterogeneous amphipods were employed, with large numbers of individuals needed to offset the potential effects of inter-individual variation in toxicant response. Even with the vast numbers of individuals utilised in each of these tests (in excess of 200 and up to 1 000 individuals for the reproduction test (Mann et al, 2009)), a large degree of variance can still be observed both within and between replicates and treatments. Previously, we demonstrated that different genotypes can give rise to differential stress response; therefore, one possible explanation for the large discrepancies observed may be attributed to the use of genetically heterogeneous test populations.…”