These are the scanned electronic copies of field and lab books used at Casey Station, Davis Station, Macquarie Island and Kingston between 2007 and 2012 as part of ASAC (AAS) project 2933 - Developing water and sediment quality guidelines for Antarctica: Responses of Antarctic marine biota to contaminants.

Study location and species The four species used in this study were collected from subantarctic Macquarie Island (54.6167 degrees S, 158.8500 degrees E), just north of the Antarctic Convergence in the Southern Ocean. Sea temperatures surrounding Macquarie Island are relatively stable throughout the year, with average temperatures ranging from ~4 to 7 degrees C [25]. Collection sites were free from any obvious signs of contamination and did not have elevated concentrations of metals as confirmed by analysis of seawater samples from the collection sites by inductively coupled plasma optical emission spectrometry (ICP-OES; Varian 720-ES). Toxicity tests were conducted at Macquarie Island over the 2013/14 austral summer, and at the Australian Antarctic Division (AAD) in Tasmania, Australia, from 2013 to 2015. The aquarium at the AAD used for culturing and for holding biota prior to their use in tests was maintained at a temperature of 5.8 degrees C under flow-through conditions (at 0.49L/sec). Individuals for toxicity tests on the island and individuals for return to Australia for culturing were collected from a range of habitats within the intertidal and subtidal zones. All species were highly abundant in each of their respective habitats. The gastropod Laevilittorina caliginosa was collected from pools high on the intertidal zone; the flatworm Obrimoposthia ohlini, from the undersides of boulders from the intertidal to shallow subtidal areas; the bivalve Gaimardia trapesina, from several macroalgae species in high energy locations in the shallow subtidal; and the isopod Limnoria stephenseni, from the floating fronds of the kelp Macrocystis pyrifera, which were located several hundred meters offshore. Test specimens were acclimated to laboratory conditions 24 h to 48 h prior to commencement of tests. Juvenile flatworms, isopods and gastropods were all products of reproduction in the laboratory at the AAD, and hence their approximate age at testing is known. The flatworms hatched from small (2 mm in diameter) brown eggs, laid on rocks or on the side of aquaria. The flatworms exhibited age based morphological differences; juvenile flatworms were light grey in colour, while the adults were black. The gastropods hatched from small (1 mm in diameter) translucent eggs laid on weed, often in a cluster. For flatworms and gastropods, juveniles were not all the same age at testing due to differing hatching times, with ages ranging from 2 weeks to 3 months. In contrast, juvenile isopods were all the same age. Although brooding isopods were not observed, juveniles were noticed during routine feeding, thus were likely within 2-3 days of being released, 6 months after adults were brought from the field to the aquarium. The tests with these juvenile isopods were done within 1 week of their being observed. Care was taken to collect adults from the field, for each species, within a narrow size range to minimise differences in ages between individuals tested (Table 1). However, ages of adults individuals used in tests are unknown. The smaller size class of bivalves tested (juveniles: 2.5 plus or minus 0.5 mm, Table 1) was also collected from the field along with the adults (8.0 plus or minus 1.0 mm, Table 1). Based on knowledge on the growth rate of this species (0.8 mm per year; Everson [26], the smaller size class likely represents a young adult of approximately 2.5 to 4 y old, as opposed to a juvenile stage, and adults collected were approximately 9 to 11 y old. Toxicity tests A static non-renewal test regime was used for all tests. Two replicate tests were done for each species at each life stage, with the exception of the juvenile isopods, where due to the limited number of individuals available, only one test was done. Longer tests durations of 14 days were done for acute responses due to the longer life span and response to contaminants compared to temperate and tropical species as determined in previous studies [7, 27]. All experimental vials and glassware were washed in 10% nitric acid and rinsed thoroughly with MilliQ water three times before use. Tests were done in lidded polyethylene vials of varying sizes, depending on the size and number of individuals in the test (Table 1). Water was not aerated as DO stayed relatively high for tests due to high dissolution rates in cold water. Acid washed and Milli-Q rinsed mesh (600 micron nylon) was provided for isopods to rest on, while no structure was added to vials for the other test species. Test solutions were prepared 24 h prior to the addition of invertebrates. Five copper concentrations in seawater were prepared using a 500 mg/L Univar analytical grade CuSO4 in MilliQ stock solution, plus a control for each test. Seawater was filtered to 0.45 microns, and water quality parameters were measured using a TPS 90-FL multimeter at the start (d 0) and end (d 14) of tests. Dissolved oxygen (DO) was greater than 80% saturation, salinity was 33 to 35 ppt, and pH was 8.1 to 8.3 at the start of tests. Tests were kept in controlled temperature cabinets set at 6 degrees C under 16:8h light:dark during the summer, and 12:12 for tests during the rest of the year (light intensity of 2360 lux). Temperatures within cabinets were monitored throughout the test using Thermochron iButton data loggers. Water samples of each test concentration were taken at the start (day 0) and end of tests (day 14). Samples were filtered through an acid and Milli-Q rinsed, 0.45 microns Minisart syringe filter and acidified with 1% ultra-pure nitric acid before being analysed by ICP-OES to determine dissolved metal concentrations. Measured concentrations at the start of tests were within 96% of nominal target concentrations. Averages between measured concentrations at the start and end of tests were made to estimate exposure concentrations, which were subsequently used in statistical analyses to determine point estimates (Table 2). Both survival and sublethal (behavioural) endpoints were used to determine sensitivity to copper. Vials were checked daily and survival and sublethal responses were observed and recorded on days 1, 2, 4, 7, 10 and 14. Tests were terminated when surviving individuals occurred in less than two concentrations, which was generally at 14 d for all species except for bivalves, in which this occurred sooner (7 to 10 d). Gastropods were scored as dead when their operculum was open and there was no response to stimulus (touch of a probe) on the operculum. Flatworms were scored as dead when there was no movement. Bivalves was scored as dead when there was no movement and when the shells were gaping open due to dysfunctional adductor muscles. Isopods were scored as dead when there was no movement of any appendages. The behavioural endpoint scored for each species was attachment, which indicated healthy and active individuals. For gastropods, this meant the foot was fully extended and attached to experimental vials; for flatworms, the whole body was able to attach (as those affected by copper appeared slightly contracted and could not lie flat); for bivalves, the byssal threads were used to fix individuals to the bottom of the vial, with the siphon also visible and shell slightly open for water exchange; and for isopods, individuals were either holding onto the provided mesh or were swimming, in which case they often reattached to the mesh during observation.

Study location and test species Subantarctic Macquarie Island lies in the Southern Ocean, just north of the Antarctic Convergence at 54 degrees 30' S, 158 degrees 57' E. Its climate is driven by oceanic processes, resulting in highly stable daily and inter-seasonal air and sea temperatures (Pendlebury and Barnes-Keoghan, 2007). Temperatures in intertidal rock pools (0.5 to 2 m deep) were logged with Thermochron ibuttons over two consecutive summers and averaged 6.5 (plus or minus 0.5) degrees C. The island is relatively pristine and in many areas there has been no past exposure to contamination. To confirm sites used for invertebrate collections were free from metal contamination, seawater samples were taken and analysed by inductively coupled plasma optical emission spectrometry (ICP-OES; Varian 720-ES; S1) The four invertebrate species used in this study were drawn from a range of taxa and ecological niches (Figure 1). The isopod Limnoria stephenseni was collected from floating fronds of the kelp Macrosystis pyrifera, which occurs several hundred meters offshore. The copepod Harpacticus sp. and bivalve Gaimardia trapesina were collected from algal species in the high energy shallow, subtidal zone. Finally, the flatworm Obrimoposthia ohlini was collected from the undersides of boulders throughout the intertidal zone. We hypothesised L. stephenseni would be particularly sensitive to changes in salinity and temperature due to its distribution in the deeper and relatively stable subtidal areas, while O. ohlini would be less sensitive due to its distribution high in the intertidal zone and exposure to naturally variable conditions. We reasoned that the remaining two species, G. trapesina, and Harpacticus sp. were intermediate in the conditions to which they are naturally exposed and hence would likely be intermediate in their response. Test procedure The combined effect of salinity, temperature and copper on biota was determined using a multi-factorial design. A range of copper concentrations were tested with each combination of temperatures and salinities, so that there were up to 9 copper toxicity tests simultaneously conducted per species (Table 1). Experiments on L. stephenseni and Harpacticus sp. were done on Macquarie Island within 2 to 3 days of collection, during which they were acclimated to laboratory conditions. While, G. trapesina and O. ohlini were transported by ship to Australia in a recirculating aquarium system and maintained in a recirculating aquarium at the Australian Antarctic Division in Hobart, both at 6 degreesC. These two taxa were used in experiments within 3 months of their collection. A limited number of G. trapesina and O. ohlini were available, resulting in fewer combinations of stressors tested. Controls for the temperature and salinity treatments were set at ambient levels of 35 plus or minus 0.1 ppt and 5.5 to 6 degreesC for all species. The lowered control temperature for the bivalve reflected the cooler seasonal temperatures at time of testing and lower position within the intertidal. Previous tests conducted under these ambient conditions provided information on the ranges of relevant copper concentrations, appropriate test durations, and water change regimes for each taxon (Holan et al., 2017, Holan et al., 2016b). From these previous studies, we determined that a test duration of 14 d was sometimes required with 7 d often being the best outcome for most species due to high control survival and sufficient response across concentrations. The bivalve G. trapesina was an exception to this due to unfavourable water quality after 3 days in previous work (Holan et al., 2016). For the other three species, this longer duration for acute tests, compared to tests with tropical and temperature species (24 to 96 h) was consistent with previous Antarctic studies that have required longer durations in order to elicit an acute response in biota (King and Riddle, 2001, Marcus Zamora et al., 2015, Sfiligoj et al., 2015). Experimental variables (volume of water, density of test organisms, copper concentrations, temperatures and salinities) differed for each experiment due to differences between each species (Table 1). The temperature increases that were tested (2 to 4 degreesC) reflected the increased sea and air temperatures predicted for the region tested by 2100 (Collins et al., 2013). Treatments were prepared 24 h prior to the addition of animals. Seawater was filtered to 0.45 microns and water quality was measured using a TPS 90-FL multimeter at the start and end of tests. Dissolved oxygen was greater than 80% saturation and pH was 8.1 to 8.3 at the start of tests. All experimental vials and glassware were washed with 10% nitric acid and rinsed with MilliQ water three times before use. Salinity of test solutions was prepared by dilution through the addition of MilliQ water. Copper treatments using the filtered seawater at altered salinities were prepared using 500mg/L CuSO4 (Analytical grade, Univar) in MilliQ water stock solution. Samples of test solutions for metal analysis by ICP-OES were taken at the start and end of tests (on days 0 and 14). Details of ICP-OES procedures are described in the Supplemental material (S4). Samples were taken using a 0.45 µm syringe filter that had been acid and Milli-Q rinsed. Samples were then acidified with 1% diluted ultra-pure nitric acid (65% Merck Suprapur). Measured concentrations at the start of tests were within 96% of nominal concentrations. In order to determine approximate exposure concentrations for each treatment, we averaged the 0 d and 14 d measured concentrations (Table 1). Tests were conducted in temperature controlled cabinets at a light intensity of 2360 lux. At the Macquarie Island station a light-dark regime of 16:8 h was used to mimic summer conditions. In the laboratories in Kingston, Australia, a 12:12 h regime was used to simulate Autum light conditions (as appropriate for the time of testing). Test individuals were slowly acclimated to treatment temperatures over 1 to 2 h before being added to treatments. Temperatures were monitored using Thermochron ibutton data loggers within the cabinets for the duration of the tests. Determination of mortality of individuals differed for each taxon. Mortality was recorded for Gaimardia trapesina when shells were open due to dysfunctional adductor muscles; for Obrimoposthia ohlini when individuals were inactive and covered in mucous; for Limnoria stephenseni when individuals were inactive after gentle stimulation with a stream of water from a pipette; and for Harpacticus sp. when urosomes were perpendicular to prosomes (as used in other studies with copepods; see Kwok and Leung, 2005). All dead individuals were removed from test vials.

Human impacts threaten not only species, but also entire ecosystems. Ecosystems under stress can collapse or transition into different states, potentially reducing biodiversity at a variety of scales. Here we examine the vulnerability of shallow invertebrate-dominated ecosystems on polar seabeds, which may be threatened for several reasons. These unique communities consist of dark-adapted animals that rely on almost year-round sea-ice cover to create low-light shallow marine environments. Climate change is likely to cause early sea-ice break-out in some parts of Antarctica, which will dramatically increase the amount of light reaching the seabed. This will potentially result in ecological regime shifts, where invertebrate-dominated communities are replaced by macroalgal beds. Habitat for these endemic invertebrate ecosystems is globally rare, and the fragmented nature of their distribution along Antarctic coast increases their sensitivity to change. At the same time, human activities in Antarctica are concentrated in areas where these habitats occur, compounding potential impacts. While there are clear mechanisms for these threats, lack of knowledge about the current spatial distribution of these ecosystems makes it difficult to predict the extent of ecosystem loss, and the potential for recovery. In this paper we describe shallow ice-covered ecosystems, their association with the environment, and the reasons for their vulnerability. We estimate their spatial distribution around Antarctica using sea-ice and bathymetric data, and apply the IUCN Red List of Ecosystems criteria to formally assess their vulnerability. We conclude that shallow ice-covered ecosystems should be considered near threatened to vulnerable in places, although the magnitude of risk is spatially variable. This dataset comprises two files. Both are provided in netCDF format in polar stereographic project (see nc file for projection details). light_budget_6km.nc : this gives the estimated annual light budget (in mol photons/m^2/year) at the surface of the water column, having been adjusted for sea ice cover (see paper for details). This is calculated on the 6.25km grid associated with the sea ice concentration data. benthic_light_500m.nc : this gives the estimated annual light budget (in mol photons/m^2/year) at the sea floor, having been further adjusted for water depth. It is provided on a 500m grid (as per the IBCSO bathymetry used). Areas deeper than 200m are given no-data values, and areas outside of the coverage of the sea ice grid are assigned a value of -999. See paper for details.

Mineralogy data collected from the CEAMARC-CASO voyage of the Aurora Australis during the 2007-2008 summer season. The data consist of a large number of images, plus documents detailing analysis methods and file descriptions. Taken from the "Methods" document in the download file: CEAMARC MINERALOGY METHODS Margaret Lindsay August 2009 Mineralogy sampling method: (numbers in brackets refer to image below) Individual bags containing the samples taken during the CEAMARC 2007/08 voyage (1) were emptied in to a sorting tray and slightly defrosted to enable the biota to be separated and sorted in to like biota (2). Taxonomic samples were selected to represent different species. The taxonomy sample was moved onto the bench and allocated a STD barcode, a photo was taken (3) and the image number, barcode and 'identification' of the biota was recorded. From the taxonomy sample a small (larger than 0.05g) sample of the individual was dissected, weighed (4) and bagged separately, this sub-sample became the 'mineralogy sample' that were sent to Damien Gore at Macquarie University on 21/05/2009 for mineralogy analysis by Damien Gore and Peter Johnston. Samples were tracked using the Sample Tracking Database (located \\aad.gov.au\files\HIRP\new-shared-hirp\30 Samples tracking + LIMS (Lab Inf Management Sys)\Sample Tracking Database\HIRP STD Working). The key barcodes are: The nally bin's containing the CEAMARC samples are located in reefer 1 (-20 C) (barcode 11919). The original CEAMARC samples (parent container) are in nally bins 14762 and 14759. The taxonomy samples are in a nally barcoded as 70469 (contains 10 bags). The mineralogy samples are in a nally bin barcoded 70472 (contains three bags) and are currently at Macquarie University for mineralogy analysis. Data was entered during the lab process into the spreadsheet file - Sub sampling taxonomy and mineralogy.xls the details of the spreadsheets contents; The list below describes each column in the 'Taxonomy and Mineralogy', 'bamboo coral' and 'other analyses' sheets from the excel file - Sub sampling taxonomy and mineralogy.xls (location described in G:\CEAMARC\CEAMARC MINERALOGY FILE DESCRIPTIONS.doc) Date sampled Date that the taxonomic samples were dissected to obtain the mineralogy samples Parent barcode STD barcode for the nally bin that the samples are located in Site barcode STD barcode for the CEAMARC site and deployment CEAMARC site number CEAMARC voyage sample site number CEAMARC event number The CEAMARC voyage event number is the sampling devices deployment number, related to CEAMARC site number Taxonomy bag barcode STD barcode for the bag that contains the taxonomy samples Image number The image number of the taxonomy sample in it's entirety before dissected to obtain the mineralogy sample. Image contains the label from the initial sample and the sub sample barcode (for taxonomy) Sub sample barcode (for taxonomy) The STD barcode allocated to the taxonomy sample Analyses label for mineralogy The number (identical to sub sample barcode number) that identifies the mineralogy sample and links it back to the taxonomic sample. Analysis sample weight The weight in grams of the dissected part that is the mineralogy sample. Mineralogy bag barcode STD barcode for the bag that contains the mineralogy samples Identification Biota sample identification eg. Gorgonian, bryozoan, ophiuroids Mineralogy sample size Relative size of sample sent off for mineralogy analysis; small sample, medium sample or large sample. Taxonomy sample size Relative size of sample small sample; medium sample or large sample (suitable for further analysis). The 'KRILL' sheet in the above excel file has the following columns; Date sub sampled Date that the taxonomic samples were dissected to obtain the mineralogy samples Sample details Sample code used to label the krill sample Taxonomy bag barcode STD barcode for the bag that contains the taxonomy samples Image number The image number of the taxonomy sample in it's entirety before dissected to obtain the mineralogy sample. Image contains the label from the initial sample and the sub sample barcode (for taxonomy) Sub sample barcode (for taxonomy) The STD barcode allocated to the taxonomy sample Analyses label for mineralogy The number (identical to sub sample barcode number) that identifies the mineralogy sample and links it back to the taxonomic sample. Analysis sample weight The weight in grams of the dissected part that is the mineralogy sample. Mineralogy bag barcode STD barcode for the bag that contains the mineralogy samples Identification Biota sample identification eg. Gorgonian, bryozoan, ophiuroids Mineralogy sample size Relative size of sample sent off for mineralogy analysis; small sample, medium sample or large sample. Taxonomy sample size Relative size of sample small sample; medium sample or large sample (suitable for further analysis). Voyage The ANARE Voyage number and year is expressed as V4 02/03 Station Station number that the samples were obtained from Date Date that the samples were taken during the voyage Time Time that the samples were taken during the voyage Location Location that the samples were taken from during the voyage Net The RMT 8 and 1 were used to collect the krill Depth The depth that the samples were obtained from (25 meters) Total mineralogy samples 1033 mineralogy samples + 15 bamboo coral samples (+ 12 krill samples) = 1060 samples

Metadata record for data from AAS (ASAC) Project 2933. While it is generally thought that Antarctic organisms are highly sensitive to pollution, there is little data to support or disprove this. Such data is essential if realistic environmental guidelines, which take into account unique physical, biological and chemical characteristics of the Antarctic environment, are to be developed. Factors that modify bioavailability, and the effects of common contaminants on a range of Antarctic organisms from micro-algae to macro-invertebrates will be examined. Risk assessment techniques developed will provide the scientific basis for prioritising contaminated site remediation activities in marine environments, and will contribute to the development of guidelines specific to Antarctica. Amphipod and Isopod toxicity tests, Kingston 2007 Filename: Amphipod and Isopod test results.xls Test animals were collected from near shore environments at Casey Station, East Antarctica during Dec 2006 - Jan 2007, and transported to culturing facilities at the Australian Antarctic Division in Tasmania, where tests were conducted during 2007. The test animals were exposed to metals in non-renewable static tests in vials containing 50 mL of the test solution at ambient Antarctic coastal salinity of 34 ppt. Tests were held in temperature controlled cabinets (incubators) at a temperature of 0 degrees C (plus or minus approximately 1 degrees C). Five to eight test animals were introduced into each of 3 replicate vials per treatment at test commencement, and were exposed for 10 to 12 weeks during which periodic observations were made. Test solutions were renewed in weekly water changes. Periodic observations (time since start of test) are given in hr (hours), d (days) or w (weeks). At each observation time, test animals were scored in one of the Endpoint categories described on each worksheet. Each worksheet provides data for a particular test taxa (slater isopods, small red isopods, spider amphipods and Orange Long Antennae Amphipods - taxonomy to be verified) for a given test number (T01, T02) and a given metal contaminant (copper, zinc, cadmium). Test information is provided in the first 14 rows of each worksheet, e.g. Site of collection, Test start date, Endpoint categories etc. ASU = artificial settlement units (plastic scourers used by Sarah Richards, which had been deployed in Newcomb Bay in approximately the year 2000). Conc micrograms/L are nominal concentrations. Measured concentrations are provided in the worksheet: /Amph and Isop T01-02 CHEMISTRY SUMM Test temperature was 0 degrees C unless otherwise stated. Unit for all temperature data is degrees C. The file contains the following worksheets: Worksheet: /Amph and Isop T01-02 CHEMISTRY SUMM Chemistry data as provided also in Kingston 07 Chemistry_Amph and Iso.xls described below. Worksheet: /Slater isopods T01 Cu Test taxa: Slater isopod; Test ID: T01, Kingston 2007; Metal contaminant: copper Worksheet: /Slater isopods T01 Zn Test taxa: Slater isopod; Test ID: T01, Kingston 2007; Metal contaminant: zinc Worksheet: /Slater isopods T01 Cd Test taxa: Slater isopod; Test ID: T01, Kingston 2007; Metal contaminant: cadmium Worksheet: /Small red isopods T02 Cu Test taxa: Small red isopods; Test ID: T02, Kingston 2007; Metal contaminant: copper Worksheet: /Small red isopods T02 Zn Test taxa: Small red isopods; Test ID: T02, Kingston 2007; Metal contaminant: zinc Worksheet: /Spider Amphipods T01 Cu Test taxa: Spider Amphipods; Test ID: T01, Kingston 2007; Metal contaminant: copper Worksheet: /Orange LongAnt Amph T01 Cu Test taxa: Orange Long Antenae Amphipods; Test ID: T01, Kingston 2007; Metal contaminant: copper Filename:Kingston 07 Chemistry_Amph and Iso.xls Metal concentrations in test solutions were analysed using an ICP-AES, by Ashley Townsend at the Central Science Laboratory, University of Tasmania, Hobart. Worksheet: /Amph and Isop T01-02 Summary Summary of chemistry data for Amphipod and Isopod tests Worksheets: /From Ash.... Series of raw data worksheets provided by Ashley, each with date stamp (ddmmyy).

Depth related changes in the composition of infaunal invertebrate communities were investigated at two sites in the Windmill Islands around Casey station, East Antarctica, during the 2006/07 summer. Sediment cores (10cm deep x 10cm diameter) were collected from 4 depths (7m, 11m, 17, and 22m) from each of three transects at two sites (McGrady Cove and O'Brien Bay 1). Cores were sieved through a 500 micron mesh and extracted fauna were preserved in 8% formalin and were later counted and identified to species or to morphospecies established through previous infaunal research at Casey. This work was conducted as part of ASAC 2201 (ASAC_2201).

Image data (both stills and video) collected from the CEAMARC-CASO voyage of the Aurora Australis during the 2007-2008 summer season. The data consist of a large number of images, plus documents detailing analysis methods, file descriptions and an AMSA (Australian Maritime Safety Authority) report.

(SRE4) was a large, long term (5 year) field experiment run at Casey Station (from 2001 to 2006) testing the effects of 4 different hydrocarbons on marine sediment ecosystems. Four different types of hydrocarbons were individually mixed with defaunated marine sediments and deployed in trays on the seabed at O'Brien Bay-1. Trays were collected after deployment periods of 5 weeks, 56 weeks, 62 weeks, 2 years and 5 years. In addition there was a bioturbation treatment using the burrowing urchin Abatus (at 56 weeks only). Samples were collected from 4 replicate trays of each treatment at each sampling time. Analyses were done of sediment hydrocarbon chemistry, microbial communities, meiofaunal communities, macrofaunal communities and diatom communities. The hydrocarbon treatments were: a synthetic Mobil lubricating oil; the same Mobil lubricating oil after 125? hours use in a vehicle engine; a Fuchs synthetic lubricating oil marketed as highly biodegradable; and Special Antarctic Blend diesel fuel (SAB). A control uncontaminated sediment treatment was used for comparison.

Sediment Recruitment Experiment 4 (SRE4) was a large, long term (5 year) field experiment run at Casey Station (from 2001 to 2006) testing the effects of 4 different hydrocarbons on marine sediment ecosystems. Four different types of hydrocarbons were individually mixed with defaunated marine sediments and deployed in trays on the seabed at O'Brien Bay-1. Trays were collected after deployment periods of 5 weeks, 56 weeks, 62 weeks, 2 years and 5 years. In addition there was a bioturbation treatment using the burrowing urchin Abatus (at 56 weeks only). Samples were collected from 4 replicate trays of each treatment at each sampling time. Analyses were done of sediment hydrocarbon chemistry, microbial communities, meiofaunal communities, macrofaunal communities and diatom communities. The hydrocarbon treatments were: a synthetic Mobil lubricating oil; the same Mobil lubricating oil after 125? hours use in a vehicle engine; a Fuchs synthetic lubricating oil marketed as highly biodegradable; and Special Antarctic Blend diesel fuel (SAB). A control uncontaminated sediment treatment was used for comparison.