A rapid amphipod reproduction test for sediment quality assessment: In situ bioassays do not replicate laboratory bioassays

Abstract

An underlying assumption of laboratory-based toxicity tests is that the sensitivity and exposure of organisms in the laboratory is comparable to that in the field. We sought to make a comparison between field-based and laboratory-based sediment toxicity tests using a recently developed rapid amphipod reproduction test that encompasses gametogenesis, fertilization, and embryo development before hatching. The test species, Melita plumulosa, is an epibenthic, detritivorous amphipod native to Eastern Australia. Test sediments were sourced from Lake Macquarie, a large saltwater lagoon located 100 km north of Sydney (New South Wales, Australia) that has received heavy-metal pollution over many decades, primarily from a Pb/Zn smelter but also from collieries, coal-fired power stations, and urban areas. This has led to a north-south trace-metal concentration gradient, including Pb, Zn, Cd and Cu, in the sediments of Lake Macquarie. Sediments from these northern bays were demonstrated to reduce amphipod fecundity in laboratory-based tests. For the current study, the amphipod reproduction test has been modified for use in situ. In situ test chambers were deployed at the mouth of Cockle Creek, Lake Macquarie. Sediments that were demonstrated to reduce fecundity of M. plumulosa in the laboratory reproduction test were not similarly toxic when amphipods were exposed to the same sediments in situ. Factors related to the regular tidal renewal of overlying water likely altered exposure profiles in situ, including the provision of additional or alternative nutrition that obviated the need for amphipods to interact with the contaminated sediments, and a washout effect that prevented the accretion of dissolved zinc in the overlying water.

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

“…A study by Mann et al (2010) showed that laboratory tests demonstrated the contaminated field sediment to have high reproductive toxicity and confirmed previously established results; however, amphipods used in in situ bioassays displayed no evidence of reduced reproductive success. It was hypothesised that these discrepancies between the laboratory test results and the in situ bioassays are likely due to tidal water exchanges that can affect the bioavailability of contaminants in the overlying water as compared to the static www.intechopen.com laboratory tests (Mann et al, 2010). Additionally, other environmental fluctuations such as precipitation and the presence of other biota not present in the laboratory tests may also contribute to the bioavailability of contaminants within each test system.…”

“…It has also been demonstrated that the results of laboratory tests on M. plumulosa are not always replicable in in situ bioassays (Mann et al, 2010;Wilkie et al, 2010). A study by Mann et al (2010) showed that laboratory tests demonstrated the contaminated field sediment to have high reproductive toxicity and confirmed previously established results; however, amphipods used in in situ bioassays displayed no evidence of reduced reproductive success.…”

“…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.…”

The impact of sediment bioturbation by secondary organisms on metal bioavailability, bioaccumulation and toxicity to target organisms in benthic bioassays: Implications for sediment quality assessment

“…The difficulties associated with extrapolating test outcomes from laboratory-based bioassays to conditions experienced in the natural environment is well documented (Burton et al, 2005;Mann et al, 2010, Belzunce-Segarra et al, 2015, as is the difficulty of designing robust field-based tests. Observations of both biotic (e.g.…”

Foraging, feeding, and reproduction on silica substrate: Increased waterborne zinc toxicity to the estuarine epibenthic amphipod Melita plumulosa

“…All the laboratory protocols with M. plumulosa have relied on natural sediments for the cultures of M. plumulosa and to provide control sediments for toxicity tests [7,12,13]. The sediment used in the laboratory cultures and as control sediment is a silty sediment collected from within the Sydney urban area.…”