This metadata record will contain the results of bioassays conducted to characterise the response of Antarctic near-shore marine zooplankton to hydrocarbon contaminants in Special Antarctic Blend (SAB) diesel fuels commonly used in Antarctica. The results from one summer season (2010-11) are in this record.

This was conducted under the AAS Project 3054: Ecological risks from oil products used in Antarctica: characterising hydrocarbon behaviour and assessing toxicity on sensitive early life stages of Antarctic marine invertebrates.

Exposure solutions of fuel were experimentally mixed by slow stir of fuel and seawater in temperature control cabinets at -1 degree C to prepare a mixture of fuel hydrocarbons in filtered seawater (FSW) termed the Water Accommodated Fraction (WAF). WAF was produced by adding fuel to seawater in 5 L or 10 L Pyrex glass bottles using a ratio of 1:24 Fuel : FSW. This mixture was stirred at slow speed with minimal vortex for 18 h on a magnetic stirrer. The mixture was settled for 6 h before the water portion was drawn from beneath the fuel.

Ecotoxicological bioassays were conducted at Davis Stations in the 2010/11 summer season using SAB WAF to prepare experimental treatments consisting of WAF dilution series. For each bioassay, treatments consisted of undiluted 100% WAF and dilutions of 10%, 17%, 25% and 50% of WAFs in FSW, to test the toxicity of water accommodated fractions of these three fuels on Antarctic both the zooplankton community and single copepod species.

Bioassays were conducted in open vessels (glass jars or beakers) in temperature controlled cabinets.

Mortality was observed at endpoints of 24 hrs, 48 hrs, 96 hrs, 7 days, 8 days, 9 days, 10 days, 11days, 12 days, 14 days, 15 days, and 16 days. New WAF solutions were prepared at the 7 day interval to replenish the experimental treatments. Deionised water was added to test solutions as required to maintain test solution volume and salinity. Water quality data was collected at each water change. Samples of test treatments for chemical analysis of hydrocarbon concentration were taken at each water change. Results of these analyses are not included as delayed progress with HC analyses impacted on quality of samples and these data were not used.

This dataset consists of Excel spreadsheets. The file name code for zooplankton bioassays is;

Project number_Season_Taxa_Test name

Eg AAS_3054_10-11_zooplankton_m1

Project number : AAS_3054

Season : 2010/11 season

Taxa: Zooplankton Community

Test name: M1 =Multi-species test 1

Bioassay spreadsheets contain the results of bioassays for a species or the zooplankton community. Where replicate tests were conducted, each experiment is on a separate worksheet. The worksheet labelled "Test conditions" shows details of Test name, dates, animal collection details, laboratory holding conditions, details of water accommodated fractions (WAF), and bioassay conditions. The worksheet labelled "Counts" has a table for each of the replicates, arranged into a column for each treatment type. These tables show the number or dead individuals which were found and removed at each of the observation days.

The worksheet labelled "Totals" has calculations of total number of individuals (of all species) which were found dead at each observation day in each replicate. It also gives the mean and standard deviation for each of the treatments.

Further information on the zooplankton community structure in the 6 samples taken across the summer, based on the community in the toxicity tests and trials, is also included in the spreadsheet "AAS_3054_10-11_zooplankton_CommStructure".

Sampling locations were near-shore from Davis Station, Vestfold Hills and from O'Gorman Rocks, southwest of Anchorage Island and northwest of Plough Island.