This dataset is derived from sediment trap records collected by Thomas Trull as part of the multidisciplinary SAZ Project initiated in 1997 by the Antarctic Cooperative Research Centre (ACE CRC) (Trull et al 2001b). The current submission provides data not included in Wilks et al. (submitted) 'Biogeochemical flux and phytoplankton assemblage variability: A unique year-long sediment trap record in the Australian Sector of the Subantarctic Zone.' This dataset contains three parts: Supplementary Table 1 describes sediment trap deployment information and current speed measured during deployment. Supplementary tables 2a and 2b are raw diatom counts of every species encountered at the site, at every sampling cup. Table 2a contains the 500 m trap depth record, while table 2b is for the 2000 m trap depth record. Supplementary table 3 contains environmental data (chlorophyll-a, photosynthetically active radiation, and sea surface temperature) for each cup record.

Live O. orensanzi were found in the AAD's Marine Research Facility emerging from sediments during feeding on 3 July 2014. It is likely that live specimens were included in samples collected for another species, Antarctonemertes sp. from intertidal rocky areas at Beall Island near Casey station (66 30.4265 degree S, 110 45.851 degrees E), East Antarctica in January and February 2014. It is also possible that the O. orensanzi were collected from southeast Newcomb Bay, adjacent to Casey station on 2 and 3 of February 2012 (Figure 4), and survived in the Marine Research Facility's aquarium, but this is considered less likely. Experiments were conducted at the AAD's quarantine facility in Kingston, Tasmania, between 19 July and 2 September 2014. This metadata record contains the results from bioassays conducted to show the response of Antarctic Polychaetes Ophryotrocha orensanzi to contamination from combinations if IFO 180 fuel and the fuel dispersants Ardrox 6129, Slickgone LTSW and Slickgone NS. Test solutions were prepared following the methods of Singer et al. (2000) with modifications by Barron and Ka'aihue (2003) and others. Water accommodated fractions of fuel in water (WAF) were produced using a 1:25 (v/v) fuel to FSW ratio in accordance with studies by Payne et al. (2014) and Brown et al., (2016) to facilitate comparability of results. Chemically enhanced water accommodated fractions (CEWAF) were made following a lower 1:100 (v/v) fuel to FSW ratio. A 1:20 (v/v) dispersant to fuel ratio was used for all three dispersants, an application rate of 1:20 dispersant to fuel rate was used both because this is the standard default application rate used in the field and to increase comparability to previous studies. Dispersant only mixes were made according to CEWAF specifications, substituting FSW for fuel. Test mixes were prepared in dark temperature-controlled cabinets at 0 plus or minus 1 degree C. Mixes were made in two L or five L glass aspirator bottles using a magnetic stirrer. Mix preparation followed the pre-vortex method in which a 20 - 25 % vortex was achieved in 0 plus or minus 1 degree C FSW before addition of the test materials. Once added, fuel was allowed to cool for a further 10 minutes before subsequent addition of dispersants during CEWAF preparation. Mixes were stirred for a total of 42 h with an additional settling time of 6 h following the recommendations determined as part of the hydrocarbon chemistry component of this project (Kotzakoulakis, unpublished data). The mixture was subsequently serially diluted to achieve the desired concentrations. Test concentrations were 100%, 50%, 20% and 10% for WAF and 10%, 5%, 1% and 0.1% for CEWAF. Concentrations for dispersant only treatments mimicked CEWAF in order to be directly comparable. Test solutions were kept in sealed glass bottles with minimal headspace at 0 plus or minus 1 degree C for a maximum of 3 h before use. Test dilutions were remade each four day period to replenish hydrocarbons lost through evaporation and absorption to simulate a repeated pulse exposure to the contaminant. Ninety percent of the test solution volume was replaced for each beaker during each water change by gently tipping out the solution with minimal disturbance to the test organisms. Replacement solutions were chilled to the correct temperature and replenished immediately to avoid any temperature shock to test animals. Beakers were topped up with deionized water between water changes to maintain water quality and solution volume. Bioassays were conducted in cold temperature cabinets at 0 plus or minus 1 degree C and light regimes were set to 18 h light and 6 h dark to mimic Antarctic conditions used by Brown et al. (2017). Exposure vessels were 100 ml glass beakers containing 80 ml of test solution. Beakers were left open to allow for the evaporation of lighter fuel components. Each experiment consisted of four replicates per treatment concentration, with eight to 10 individuals per replicate (8 each for Slickgone NS, 10 each for Ardrox and LTSW). Experiments ran for 12 days with observations at 24 h, 48 h, 96 h, 7 d, 8 d, 10 d and 12 d. Mortality was assessed at each observation using a Leica MZ7.5 dissecting microscope. Mortality was determined by the absence of response to stimuli, specifically lack of movement in the maxillae or mandibles. No food was added during experiments to avoid inclusion of an additional exposure pathway. Aliquots of each test concentration were taken at the beginning and end of each experiment, as well as before and after each water change to analyse the total petroleum hydrocarbon (TPH) content. Duplicate 25 ml samples were taken for each test dilution and immediately extracted with a mixture of Dichloromethane spiked with an internal standard of BrC20 (1-bromoeicosane) and cyclooctane. Extractions were analysed using Gas Chromatography with Flame Ionisation Detection (GC-FID) and Gas Chromatography mass spectrometry (GC-MS). The measured concentrations were integrated following the methods of Payne et al. (2014) to obtain a profile of hydrocarbon content over each 12 d test period.

Coccolithophore fluxes were investigated over a one-year period (2001-02) at the southern Antarctic Zone in the Australian Sector of the Southern Ocean at the site of the Southern Ocean Iron Release Experiment (SOIREE) near 61°S, 140°E. Two vertically moored sediment traps were deployed at 2000 and 3700 m below sea-level during a period of 10 months. In these data sets we present the results on the temporal and vertical variability of total coccolith flux, species composition and seasonal changes in coccolith weights of E. huxleyi populations estimated using circularly polarised micrographs analysed with C-Calcita software. A description of the field experiment, diatom and biogeochemical fluxes can be found in Rigual-Hernández et al. (2015), while a detailed description of sample processing and counting of coccolithophores can be found in Rigual-Hernández et al. (2018). Moreover, an explanation of the estimation of Emiliania huxleyi coccoliths using C-Calcita software can be also found in Rigual-Hernandez et al. (2018). Coccolithophore assemblages captured by the traps were nearly monospecific for Emiliania huxleyi morphotype B/C. Coccolith fluxes showed strong seasonal cycle at both sediment trap depths. The maximum coccolith export occurred during summer and was divided into two peaks in early January (2.2 x 109 coccoliths m-2 d-1 at 2000 m) and in mid-February (9.8 x 108 coccoliths m-2 d-1). Coccolith flux was very low in winter (down to ~7 x 107 coccoliths m-2 d-1). Coccolith fluxes in the deeper trap (3700 m) followed a similar pattern to that in the 2000 m trap with a delay of about one sampling interval. Coccoliths intercepted by the traps exhibited a weight and length reduction during summer. The annual coccolith weight at both sediment traps was 2.11 plus or minus 0.96 and 2.13 plus or minus 0.91 pg at 2000 m and 3700 m, respectively. Our coccolith mass estimation was consistent with previous reports for morphotype B/C in other regions of the Southern Ocean. Data available: two excel files containing sampling dates and depths, raw counts, relative abundance and fluxes (coccoliths m-2 d-1) of the coccolithophore species, and morphometric measurements of Emiliania huxleyi coccoliths made with C-Calcita software. Each file contains four spreadsheets: raw coccolith counts, relative abundance of coccolithophore species and coccolith flux of each coccolithophore species identified and E. huxleyi morphometrics. Detailed information of the column headings is provided below. Cup – Cup (=sample) number Depth – vertical location of the sediment trap in meters below the surface Mid-point date - Mid date of the sampling interval Length (days) – number of days the cup was open

The collection aims to showcase the range of Southern Ocean diatom species found in the major hydrological provinces of the Australian Sector of the Southern Ocean along the 140 degrees E. The collection includes specimens collected in the Sub-Antarctic Zone (SAZ), Polar Frontal Zone (PFZ) and Antarctic Zone (AZ). Samples were collected with McLane Parflux time series sediment traps placed at several depths in the SAZ (47 degrees S site), PFZ (54 degrees S site) and AZ and (61 degrees S site) during the decade 1997-2007. The shortest sampling intervals were eight days and corresponded with the austral summer and autumn, whereas the longest interval was 60 days and corresponded with austral winter. Split aliquots were obtained for taxonomic analysis via scanning electron microscopy (SEM). For improved taxonomic imaging, samples were treated with hydrochloric acid and hydrogen peroxide to remove carbonates and organic matter, respectively. A micropipette was used to transfer the suspension of selected samples to a round-glass cover slip following standard decantation method outlined by Barcena and Abrantes (1998). Samples were air-dried and coated with gold for SEM analysis. SEM analysis was carried out using a JEOL 6480LV scanning electron microscope. Taxonomy Diatoms include all algae from the Class Bacillariophyceae and follow the standardised taxonomy of World Register of Marine Species (WoRMS). Order Asterolamprales Family Asterolampraceae Asteromphalus hookeri Ehrenberg Asteromphalus hyalinus Karsten Order Achnanthales Family Cocconeidaceae Cocconeis sp. Order Bacillariales Family Bacillariaceae Fragilariopsis curta (Van Heurck) Hustedt Fragilariopsis cylindrus (Grunow) Krieger Fragilariopsis kerguelensis (O'Meara) Hustedt Fragilariopsis pseudonana (Hasle) Hasle Fragilariopsis rhombica (O'Meara) Hustedt Fragilariopsis separanda Hustedt Nitzschia bicapitata Cleve Nitzschia kolaczeckii Grunow Nitzschia sicula (Castracane) Husted var. bicuneata (Grunow) Hasle Nitzschia sicula (Castracane) Husted var. rostrata Hustedt Pseudo-nitzschia heimii Manguin Pseudo-nitzschia lineola (Cleve) Hasle Pseudo-nitzschia turgiduloides Hasle Order Chaetocerotanae incertae sedis Family Chaetoceraceae Chaetoceros aequatorialis var. antarcticus Cleve Chaetoceros atlanticus Cleve Chaetoceros dichaeta Ehrenberg Chaetoceros peruvianus Brightwell Chaetoceros sp. Order Corethrales Family Corethraceae Corethron spp. Order Coscinodiscales Family Coscinodiscaceae Stellarima stellaris (Roper) Hasle et Sims Family Hemidiscaceae Actinocyclus sp. Azpeitia tabularis (Grunow) Fryxell et Sims Hemidiscus cuneiformis Wallich Roperia tesselata (Roper) Grunow Order Hemiaulales Family Hemiaulaceae Eucampia antarctica (Castracane) Mangin Order Naviculales Family Plagiotropidaceae Tropidoneis group Family Naviculaceae Navicula directa (Smith) Ralfs Family Pleurosigmataceae Pleurosigma sp. Order Rhizosoleniales Family Rhizosoleniaceae Dactyliosolen antarcticus Castracane Rhizosolenia antennata f. semispina Sundstrom Rhizosolenia antennata (Ehrenberg) Brown f. antennata Rhizosolenia cf. costata Gersonde Rhizosolenia polydactyla Castracane f. polydactyla Rhizosolenia simplex Karsten Proboscia alata (Brightwell) Sundstrom Proboscia inermis (Castracane) Jordan Ligowski Order Thalassiosirales Family Thalassiosiraceae Porosira pseudodenticulata (Hustedt) Jouse Thalassiosira ferelineata Hasle et Fryxell Thalassiosira gracilis (Karsten) Hustedt Thalassiosira lentiginosa (Janisch) Fryxell Thalassiosira oestrupii (Ostenfeld) Hasle var. oestrupii Fryxell et Hasle Thalassiosira oliveriana (O'Meara) Makarova et Nikolaev Thalassiosira tumida (Janisch) Hasle Order Thalassionematales Family Thalassionemataceae Thalassionema nitzschioides var. lanceolatum Grunow Thalassiothrix antarctica Schimper ex Karsten Data available: 73 SEM images of the most abundant diatom species found at the three sampling sites. Samples were collected by several sediment traps placed at different depths in the Subantarctic Zone (47 degrees S site), Polar Frontal Zone (54 degrees S site) and Antarctic Zone (61 degrees S site) during the decade 1997-2007. The collection site and date for each species image can be found in Table 1 (see the word document in the download file).

Coccolithophore fluxes were investigated over a one-year period at two sites of the Subantarctic Zone in the Australian and New Zealand Sectors of the Southern Ocean. The samples from the Australian SAZ were retrieved at the SOTS observatory, which lies in the SAZ (near 47°S, 142°E), approximately 500 km south west of Tasmania. SOTS was instrumented with three moored platforms: (i) a surface tower buoy that performs meteorological measurements (the Southern Ocean Flux Station - SOFS); (ii) a surface mixed layer mooring equipped with an automated water sampler) and nutrient, carbon and biological measurement sensors (the Pulse mooring); and (iii) a bottom-tethered deep sediment trap mooring that collects sinking particle fluxes for diverse biogeochemical studies (the SAZ mooring). The samples from New Zealand came from the deep-ocean SAM mooring deployed in Subantarctic waters south east of New Zealand (46°40’S, 178’ 30°E), and was equipped with sediment traps and a suite of sensors. Here, we report the coccolith sinking assemblages captured by sediment traps at ~1000, 2000 and 3800 m depth for a year from August 2011 until July 2012 at the SOTS observatory and a sediment trap at ~1500 m depth for a year from November 2009 until October 2010 at the SAM site. A description of the field experiment, sample treatment, determination of total CaCO3 content, and estimation of coccolith and coccosphere fluxes can be found in Rigual-Hernández et al. (2020a) and Rigual-Hernández et al. (2020b). Data available: two excel files (one for each station) containing sampling dates and depths, relative abundance of coccolith sinking assemblages, and coccolith, coccosphere and total CaCO3 fluxes. Detailed information of the column headings is provided below. Cup – Cup (=sample) number Depth – vertical location of the sediment trap in meters below the surface Mid-point date - Mid date of the sampling interval Duration (days) – number of days the cup was open

This spreadsheet contains species lists and counts from four sediment trap records. The sediment traps were deployed for ~1 year north and south of the Chatham Rise, New Zealand, between 1996 and 1997. Sheets 1a and 1b refer to North Chatham Rise (NCR). 1a = the 300m trap. 1b = the 1000m trap. Sheets 2a and 2b are for the South Chatham Rise traps (SCR). 2a= 300m, 2b= 1000m. Counting was undertaken on 1/16th splits. Material was cleaned of organics before diatom counting under light microscopy. Coccolith counting on uncleaned material was only undertaken at the 300m traps. Radiolarians and silicoflagellates were counted but not identified. Diatoms and coccoliths were counted along non-overlapping transects until 300 specimens had been counted per sample, or until 10 transects had been made. This dataset includes counts of diatom, coccolithophores, radiolarians and silicoflagellates for four sediment trap records- North Chatham Rise (NCR) and South Chatham Rise (SCR) at two trap depths each (300 m and 1000 m). It is intended as supplementary material to Wilks et al. 2018 (submitted) "Diatom and coccolithophore assemblages from archival sediment trap samples of the Subtropical and Subantarctic Southwest Pacific." Numbers are raw count per sample cup. Authorities are given. Coordinates of traps given in degrees, minutes and seconds.

SAZ photos of sediment trap samples Sediment traps are cones which intercept and store falling marine particles in collection cups. The particles consist of a range of material including phytoplankton, zooplankton, faecal pellets, and dust. Each trap collects a time series of samples. The sediment traps are from deep moorings in the Southern Ocean, typically at 47S, 54S, and 61S and at around 140 degrees East. Each mooring typically has 2-3 traps between 800m and 3800m below sea-level. The samples are size fractionated into less than 1mm and greater than 1mm fractions using a 1mm sieve. Various chemical analyses and observations have been made on the less than 1mm fraction. These are photos are of greater than 1mm fraction, mainly showing 'swimmers.' Photos are mostly taken on the sieve, so the grid is 1mm for scale. Sample identification is in the file name, and also in a label in the photo. The file name format is: Typical example s02_54_800_04.jpg 1) s02: s is for SAZ. Collection season number is first year of collection season. So s02 is from SAZ 2002-2003. 2) 54: Nominal latitude. 3) 800: Nominal depth, m. 4) 04: Cup number, typically 1-21 or 1-13, single digit numbers padded with a zero to help operating systems display files in order. 5) .jpg: All photos are in jpeg format Some files have additional information at end, examples below: * FP: faecal pellet * begin and end: beginning and end of sieving process. Mostly to show faecal pellets at start that are rinsed through sieve. This work was completed as part of ASAC project 1156 (ASAC_1156). See also the metadata record 'Subantarctic Zone (SAZ) Sediment Trap Moorings' (SAZOTS).

Untreated, macerated wastewater effluent has been discharged to the sea at Davis Station since 2005, when the old wastewater treatment infrastructure was removed. This environmental assessment was instigated to guide the choice of the most suitable wastewater treatment facility at Davis. The assessment will support decisions that enable Australia to meet the standards set for the discharge of wastewaters in Antarctica in national legislation (Waste Management Regulations of the Antarctic Treaty Environmental Protection Act - ATEP) and to meet international commitments (the Madrid Protocol) and to meet Australia's aspirations to be a leader in Antarctic environmental protection. The overall objective was to provide environmental information in support of an operational infrastructure project to upgrade wastewater treatment at Davis. This information is required to ensure that the upgrade satisfies national legislation (ATEP/Waste Management Regulations), international commitments (the Madrid Protocol) and maintain the AAD's status as an international leader in environmental management. The specific objectives were to: 1. Wastewater properties: Determine the properties of discharged wastewater (contaminant levels, toxicity, microbiological hazards) as the basis for recommendations on the required level of treatment and provide further consideration of what might constitute adequate dilution and dispersal for discharge to the nearshore marine environment 2. Dispersal and dilution characteristics of marine environment: Assess the dispersing characteristics of the immediate nearshore marine environment in the vicinity of Davis Station to determine whether conditions at the existing site of effluent discharge are adequate to meet the ATEP requirement of initial dilution and rapid dispersal. 3. Environmental impacts: Describe the nature and extent of impacts to the marine environment associated with present wastewater discharge practices at Davis and determine whether wastewater discharge practices have adversely affected the local environment. 4. Evaluate treatment options: Evaluate the different levels of treatment required to mitigate and/or prevent various environmental impacts and reduce environmental risks.

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.

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.