A manipulative field experiment examining the effect of contaminated sediment on the recruitment and recolonisation of soft-sediment infauna.

Brief description

The effect of location, depth and sediment contamination on recruitment of soft-sediment assemblages were examined in a pilot experiment at Casey Station, East Antarctica. Two locations were used, a polluted bay adjacent to an old disused tip site (Brown Bay) and an undisturbed control (O'Brien Bay). At each location two types of defaunated sediment (polluted and control) were placed at 2 depths, 15 m and 25 m. Sediments were left in place over the Austral winter, from March - November. There were large differences in recruitment between the two locations and depths and some differences between the two sediment types. Brown Bay had greater recruitment than O'Brien Bay. Shallow sites had generally greater recruitment than deep, but deep sites had greater diversity (H'), richness (d) and evenness (J'). Control sediment recruited greater numbers of arthropod, gammarid and isopod taxa. There were not only differences in abundance of taxa and assemblage structure but also in spatial variability and variability of populations of certain taxa, with recruitment to the control and deep locations more variable, and recruitment in the control sediment more variable than the polluted sediment. Recruitment was influenced by a combination of location, depth and sediment type. There is some evidence of an environmental impact at the polluted site. The majority of fauna recruiting to the experiment were highly motile colonizing species with non-pelagic lecithotrophic larvae, usually brooded and released as dispersing juveniles, such as gammarids, tanaids, isopods and gastropods.

A total of 56 recruitment samples were collected. Samples were sieved at 500 micro metres and sorted mainly to species. Metal concentrations and total organic carbon concentrations are also included.

Also links to ASAC 1100.

The fields in this dataset are:

Species
Location
Site
Treatment (tmt)
Site and replicate
Toxicity
Arsenic
Cadmium
Copper
Lead
Silver
Zinc

Lineage

Progress Code: completed

Statement: Gammarid, Isopod, gastropod faunas identified at the Australian Museum. Remaining faunas identified by J. Stark.