Researchers studied persistent organohalogen contaminants (POCs) in the eastern Antarctic sector. Samples were collected during January and February 2006 and originated from 12 sampling stations. They were analysed for greater than 100 organohalogen compounds including chlorinated pesticides, polychlorinated biphenyls (PCBs), polybrominated organic compounds and polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs). The suspected naturally occurring organohalogen, 2,4,6-tribromoanisole (TBA) as well as delta-HCH; o,p'- DDE; o,p'-DDD; p,p'-DDD; p,p'-DDT; penta-chlorobenzene (PeCB); HCB; heptachlor-exoepoxide; heptachlor; trans-nonachlor, mirex and toxaphene congeners Tox-26 (B8-1413), Tox-40+41 (B8-1414+ B8-1945) and Tox-50 (B8-2229) were quantified in all samples analysed whilst PCB-101, gamma-HCH, p,p'-DDE cis-nonachlor, Tox-42a (B8-806) and Tox-44 (B8-2229) were quantified in greater than or equal to 75% of samples analysed. Organochlorine pesticides dominated measured krill contaminant burdens with hexachlorobenzene (HCB) as the single most abundant compound quantified: 4.37 ng/glw (lipid weight) or 0.2 ng/gww (wet weight). HCB concentrations were comparable to those detected at this trophic level in both the Arctic and temperate northwest Atlantic, lending support to the hypothesis that HCB will approach global equilibrium at a faster rate than other POCs. Para, para'-dichlorodiphenylethene (p,p'- DDE) was detected at notable concentrations: 2.6 ng/glw 0.13 ng/gww. In contrast to the Arctic, PCBs did not feature prominently in contaminant burdens of Antarctic krill: 1.2 ng g- 1 lw and 0.05 ng/gww., dominant PCB congeners were PCB-18, PCB-28, PCB-31 and PCB- 153. The major commercial polybrominated diphenyl ether (PBDE) congeners -99 and -47 were quantified at low background levels (0.67 ng/glw , 0.03 ng/gww and 0.35 ng/glw, 0.007 ng/gww respectively) with clear concentration spikes observed at around 70 degrees E , in the vicinity of modern, active research stations. The suspected naturally occurring brominated organic compound, 2,4,6-tribromoanisole (TBA), was a ubiquitous contaminant in all samples 49 whereas the only PCDD/Fs quantifiable were trace levels of octachlorodibenzo-p-dioxin (OCDD) and 1,2,3,4,7,8/1,2,3,4,7,9-hexachlorodibenzofuran (HxCDF). This work has been incorporated in AAS project 3115 (ASAC_3115), Persistent Organic Pollutants and Emerging Contaminants of Concern; System Input From Local and Distant Contamination Sources.

Seabird surveys in January - March 2006 of a poorly known area of the Southern Ocean adjacent to the East Antarctic coast identified six seabird communities, several of which were comparable to seabird communities identified both in adjacent sectors of the Antarctic, and elsewhere in the Southern Ocean. These results support previous proposals that the Southern Ocean seabird community is characterised by an ice-associated assemblage and an open-water assemblage, with the species composition of the assemblages reflecting local (Antarctic-resident) breeding species, and the migratory routes and feeding areas of distant-breeding taxa, respectively. Physical environmental covariates such as sea-ice cover, distance to continental shelf and time of year influenced the distribution and abundance of seabirds observed, but the roles of these factors in the observed spatial and temporal patterns in seabird assemblages was confounded by the duration of the survey. Occurrence of a number of seabird taxa exhibited significant correlations with krill densities at one or two spatial scales, but only three taxa (Arctic tern, snow petrel and dark shearwaters, i.e. sooty and short-tailed shearwaters) showed significant correlations at a range of spatial scales. Dark shearwater abundances showed correlations with krill densities across the range of spatial scales examined. This work was conducted on the BROKE-West voyage of the Aurora Australis.

This dataset contains the underway data collected during the Aurora Australis Voyage 3 2005-06. This voyage began in Hobart, and went to Mawson and Davis and conducted marine science before returning to Hobart. Underway (meteorological) data are available online via the Australian Antarctic Division Data Centre web page (or via the Related URL section). This voyage was also known as BROKE-West, and complements the BROKE-East voyage undertaken in the 1995/1996 season (voyage 4 - 199596040).

The BROKE-West survey was conducted from 30 degrees E and 80 degrees E between January and March 2006. It consisted of 1 east-west transect at the northernmost limit of the survey between 60 degrees S and 62 degrees S between the 10 and 19 of January, followed by 11 meridional transects separated by 5 degrees of longitude and extending from approximately 62 degrees S to the Antarctic continental shelf between the 19 January and 3 March. This dataset details research undertaken to determine the identity, composition and abundance of protists in the survey area. Some explanations for terms used in the dataset are as follows: 1. Group is the taxonomic Phylum, Class and occasionally Order to which the taxa belongs. The abbreviations are: a. Diatom - Diatomophyceae/Bacillariophyceae. These are subdivided into the taxonomic Orders Centrales (centric) and Pennales (pennate) b. Chryso - Chrysophyceae c. Dino - Dinophyceae d. Eugleno - Euglenophyceae e. Hapto - Haptophyceae f. Prasino - Prasinophyceae g. Silico - Dictyochales (silicoflagellates) h. Choano - Craspedophyceae /Choanoflagellida i. Ciliate - Phylum Ciliophora j. Tintinnid - Phylum Ciliophora , Order Spirotrichea, Class Tintinnida k. Protozoa - refers to grouped rare taxa belonging to a number of Classes 2. Autotroph/Heterotroph refers to the trophic status of the taxa, indicating whether they are autotrophic (plant) or heterotrophic (animal). 3. CTD Station Number refers to the station at which samples were collected. Type indicates whether the samples were collected at the surface "surf" or at the point at which there was maximum chlorophyll fluorescence detected from the CTD flurometer trace "ChlMax". The data are all cell concentration numbers. For more information, see the other metadata records related to ASAC project 40 (ASAC_40), ASAC project 2655 (ASAC_2655) and ASAC project 2679 (ASAC_2679).

This data set contains concentrations of phytoplankton, protozoa, total bacteria and metabolically active bacteria assessed by flow cytometry on transects 12, 1, 3, 5, 7, 9 and 11 of the BROKE-West survey of the Southern Ocean between January and March 2006. Only total bacterial concentrations were assessed for transect 11. Between 4 and 12 depths were sampled for marine microbes and concentrations were assessed using FACScan flowcytometer. Phytoplankton were identified and counted based on the autofluorescense of chlorophyll a when excited by the 488 nm laser of the FACScan. Protozoa were identified and counted after staining with the acid vacuole stain Lysotracker Green. Total bacteria were identified and counted using the cell permeant SYTO 13 nucleic stain. Metabolically active bacteria were identified and counted after staining for intracellular esterases with the esterase stain 6CFDA. The fields in this dataset are: Latitude Longitude Transect Number CTD number, flow file Depth (m) Total bacteria (per millilitre) Active bacteria (per millilitre) Dead bacteria (per millilitre) Protozoa (per millilitre) Phytoplankton (per millilitre) This work was completed as part of ASAC project 40 (ASAC_40).

3 litres of seawater were collected every 2nd CTD (conductivity, temperature and depth) cast on every CTD transect of the BROKE-West voyage. 7 CTD transects were completed on the BROKE-West voyage, all on southwards legs. Samples were collected at 6 depths in the top 200 m of the water column using niskin bottles. 2 litres were filtered through polycarbonate filters and 1 litre was filtered through a fibreglass filter. Chemical digestion of the polycarbonate filter enabled us to determine the particulate silicon concentration for each sample (using the nutrient autoanalyser onboard the Aurora Australis, see hydrochemistry section), fibreglass filters have been dried and stored for CHN analysis back on shore. This work was completed as part of ASAC projects 2655 and 2679 (ASAC_2655, ASAC_2679).

Locations of sampling sites for ASAC project 40 on voyage 3 of the Aurora Australis in the 2005/2006 season (the BROKE-West voyage). Samples were collected between January and March of 2008. Three datasets are currently included in this download - an excel spreadsheet and a draft publication providing details on the methodology, etc employed, as well as two copies of corrected fluoro data for BROKE-West (BW_UwayFLuChla - in excel and csv formats). Public Summary from the project: This program aims to determine the role of single celled plants, animals, bacteria and viruses in Antarctic waters. We quantify their vital role as food for other organisms, their potential influence in moderating global climate change through absorption of CO2 and production of DMS, and determine their response to effect of climate change. For more information, see the other metadata records related to ASAC project 40 (ASAC_40). ###### Taken from the abstract of the draft paper: The geographic distribution, stocks and vertical profiles of phytoplankton of the seasonal ice zone off east Antarctica were determined during the 2005-2006 austral summer as part of the Baseline Research on Oceanography, Krill and the Environment-West (BROKE-West) survey. CHEMTAX analysis of HPLC pigment samples, coupled with microscopy, permitted a detailed survey along eight transects covering an extensive area between 30 degrees E and 80 degrees E, from 62 degrees S to the fast ice. Significant differences were found in the composition and stocks of populations separated by the Southern Boundary of the Antarctic Circumpolar Current (SB), as well as a small influence of the Weddell Gyre in the western sector of the zone south of the SB (SACCZ). Within the SACCZ, we identified a primary bloom under the ice, a secondary bloom near the ice edge, and an open ocean deep population. The similarity of distribution patterns across all transects allowed us to generalise a hypothesized sequence for the season. The primary bloom was initiated by release of cells and detritus from melting sea ice, some 35 days before ice melting, with stocks of Chl a ranging from 115-239 mg.m-2, apart one leg (41 mg.m-2), which was sampled late in the season. The bloom was dominated by haptophytes (in particular, colonies and gametes of Phaeocystis antarctica), diatoms and cryptophytes (or Myrionecta rubrum). The detrital material quickly sank from the upper water column, but the bloom of diatoms and, to a lesser extent cryptophytes, continued until 20 days after ice melt. Average Chl a stocks during this bloom ranged from 56-92 mg.m-2 between transects. A bloom of Phaeocystis gametes immediately after ice melt lasted for about 10 days. Grazing activity, as indicated by phaeophytin a, also increased at the same time. The diatom bloom became senescent, probably as a result of iron exhaustion, as indicated by chlorophyllides, which reached 45% of total Chl a. The bloom then rapidly declined, apparently due to grazing krill. Well-defined 'holes' in the chlorophyll distribution of most suggested that the krill were moving southward following the retreating sea ice and clearing the ice edge bloom. There was no evidence that blooms had been terminated by sinking or by vertical mixing. It appears that grazing of the bloom and export of cellular material as faecal pellets stripped the upper water column of iron, preventing its normal recycling via the microbial network. Thus, export of iron by grazing, and possibly sedimentation, created a southward migrating iron front, limiting growth in the upper water column. North of the iron front, a recycling nanoflagellate community developed at depth, sustained by residual iron, as indicated by a close correspondence between distributions of Chl a and profiles of Fv/Fm. Its depth was independent of the mixed layer and the pycnoclines. This community consisted of haptophytes (chiefly Phaeocystis gametes), dinoflagellates, prasinophytes, cryptophytes, and some small diatoms. The community may have derived from, and was possibly sustained by, selective grazing by krill. Average stocks of Chl a ranged from 36-49 mg.m-2 between transects. North of the SB, communities were found in the mixed layer, although they still had low Fv/Fm ratios. Populations were dominated by Phaeocystis gametes (with colonies north of the southern ACC front), diatoms such as Pseudonitzschia sp., Fragilariopsis pseudonana, F. kerguelensis, F. curta, and Gymnodinium sp. Average stocks of Chl a ranged from 40-67 mg.m-2 between transects.These appeared to be recycling communities that had been advected into the BROKE-West study region. These interpretations provide a cogent explanation for the composition and structure of microbial populations in the marginal ice zone during the latter half of the summer. ###### The fields in this dataset are: Peak Pigment name Retention times Visible maxima Comments Leg Zone Latitude Longitude CTD Julian Day Date Ice free days Pigment concentrations Protists

Samples were collected at trawl stations (approximately every second CTD station), as well as opportunistically when something interesting was spotted on the Echosounder. The samples were collected with an RMT-1 plankton net and preserved in Steedman's solution. Upon returning to Australia, the samples were passed onto Kerrie Swadling, who split them with a Folsom plankton splitter and counted between 400 and 1300 animals. Every organism was identified to the lowest possible taxon - in the case of copepods, usually to species and stage level. Other taxa are to species wherever possible. All the animals were counted and the results are expressed as abundance per 1000 cubic m. The data in the spreadsheet represent a species x site matrix. The excel spreadsheet entitled 'List of major samples and activities BROKE West.xls' is a summary of the sort of samples that were collected at each station, and the purpose for which they were collected. More detailed notes about the collection of the samples are presented in the Quality field. Further information about the Trawl stations can be found in the parent BROKE-West metadata record. This work was completed as part of ASAC projects 2655 and 2679 (ASAC_2655, ASAC_2679). The fields in these excel spreadsheets are: Station Number Species Date Latitude Longitude Trawl Type Formalin - whether the samples were fixed in formalin IGR - whether the instantaneous growth rate experiment was performed Genetics - preserved in ethanol, samples retained for genetic experiments Frozen - samples frozen at -85 degrees C for chemical analysis POP - samples analysed for Persistent Organic Pollutants Density Contrast - whether the density contrast of the krill were measured Isotopes - samples retained for isotope analysis Frozen DG - digestive gland samples were frozen Ethanol (Squid) - ethanol fixed squid were retained Frozen (Fish) - frozen fish samples were retained Formalin (Fish) - formalin fixed fish samples were retained Ethanol (Fish) - ethanol fixed fish samples were retained Demography - demographic parameters were collected Other - various purposes, occasionally noted in the comments field Comments The spreadsheet 'List of major samples and activities BROKE West.xls' is marked with solid black circles, or empty white circles - the empty white circles represent Euphausia crystallorophias samples. The solid black circles represent Euphausia superba in columns F-K, M and R. In the other columns they will either represent the animal as marked (eg squid), or may be a collection of anything.

The BROKE-West survey was conducted on voyage 3 of the Aurora Australis during the 2005-3006 season. It was intended to be a comprehensive biological and oceanographic survey of the region between 30 degrees and 80 degrees east. A number of metadata records providing more detail about aspects of the voyage are linked off this metadata record. Copies of the public summaries from the underlying ASAC projects of the voyage are below: A planned acoustic biomass survey for krill in CCAMLR Division 58.4.2 (South West Indian Ocean) in January-March 2006 will produce the data for a revised catch limit on the krill fishery. The survey will utilise a standardised design as adopted in previous biomass surveys in the CCAMLR Area and will consist of 11 parallel transects between 30 degrees and 80 degrees east. A full suite of ecological measurements will be conducted: physical and chemical oceanography, primary productivity, microbial diversity, zooplankton distribution and abundance, krill distribution, abundance and demographics, fish distribution, abundance and genetics, and seabird and cetacean distribution. The three-dimensional ocean circulation from the 30 to 80 degrees E and 200nm from Antarctica is being studied through the use of direct measurements of velocity, temperature, salinity, oxygen, nutrients , chloro-flourocarbons, dissolved inorganic carbon and bio-geochemical cycles. This multi-disciplinary experiment (see also project 2655) will determine the circulation of the region, its relation to bio-geochemical cycles, carbon cycle and ecosystems. The temperature and salinity data will also be used to test for long term trends that could be related to climate change. This work was completed as part of ASAC projects 2655 and 2679 (ASAC_2655, ASAC_2679). A pdf copy of the proposed voyage track is available for download from the provided URL. Two csv files detailing the locations (latitudes and longitudes), plus times and dates (UTC) of the trawl and ctd stations on the BROKE-West voyage are available for download from the provided URL. Additional comments (where applicable) about each station are also provided.