Keyword

EARTH SCIENCE > BIOLOGICAL CLASSIFICATION > ANIMALS/INVERTEBRATES > ARTHROPODS > CRUSTACEANS > AMPHIPODS

28 record(s)
 
Type of resources
Topics
Keywords
Contact for the resource
Provided by
From 1 - 10 / 28
  • Overview The aim of this project was to investigate the genetic connectivity and diversity of Antarctic benthic amphipods over fine (100's of m's), intermediate (10's of km's) and large (1000's of km's) scales, using highly variable molecular markers. To achieve this, we developed seven microsatellite markers specific to the common Antarctic amphipod species Orchomenella franklini. A total of 718 specimens of O. franklini were collected from East Antarctica. Approximately 30 specimens were collected from each site, and sites were spatially hierarchically nested - i.e. sites (separated by 100m) were nested within locations (separated by 1-30km), which were nested within 2 broad regions (separated by approx. 1400km). Each amphipod sample was genotyped for all seven microsatellite loci (although occasionally a locus would not amplify in a given sample). This dataset provides all the resultant genetic data - that is, the size of the two alleles that were amplified for each microsatellite locus, in each of 718 amphipod specimens. Data collection and analysis Please refer to the associated publication (see below) for all relevant methodology. Explanation of worksheet Sample ID- a unique code given to identify each amphipod sample (the code itself has no actual meaning). Region- the broad region of the Antarctic coast from which each sample was collected. The two regions (Casey and Davis station) are separated by approx. 1400km. Location- the locations (within a region) from which each sample was collected. The names of each location reflect actual names registered by the Australian Antarctic Division and therefore their coordinates can be pinpointed on maps held by the Australian Antarctic Division Data Centre. Locations (and corresponding sites) written in italicised typeface are considered polluted (see publication for more information on this classification). Site- the sites sampled within each location. Sites are named simply by a two -letter abbreviation of the location they are from, followed by a lowercase 'a', 'b', 'c' or 'd' representing site 1, 2, 3 etc. Microsatellite data - this provides all the microsatellite genetic data generated for each amphipod specimen. Data are presented as the allele sizes (in number of base pairs) recorded for each of the seven microsatellite loci amplified. The seven microsatellite loci are called Orcfra3, Orcfra4, Orcfra5, Orcfra6, Orcfra12, Orcfra13, Orcfra26. As O. franklini is a diploid organism, each microsatellite locus has two allele sizes (hence why there are two columns underneath each locus). A '0' signifies that a particular locus did not amplify successfully in the corresponding organism (after at least two attempts). Samples were collected from Casey station between January 2009 and March 2009, and from Davis station between November 2009 and April 2010. Genetic data was generated and analysed between April 2009 and November 2009, and between May 2010 and April 2011. Genetic data obtained from the common Antarctic amphipod species Orchomenella franklini - Genetic data obtained from the common Antarctic amphipod species Orchomenella franklini. A total of 718 specimens were collected from sites within 20 km of Casey station or Davis station. Collection dates ranged from 2009 to 2010. Each amphipod sample was genotyped for seven microsatellite loci (although occasionally a locus would not amplify in a given sample).

  • This data record has been compiled for a statistical methods study, conducted by Abigael Proctor as part of her PhD research in 2018. The data in this record have been used to showcase a new statistical method for determining no effect concentration (NEC). The study uses the data in this record to compare NEC and LCx estimates for copper in four Antarctic marine invertebrate species. The data associated with this record are a subset of four existing larger datasets: 1. amphipod: AAS_2933_Orchomenella_pinguides_Sensitivity_metals_Davis_2010-11 2. copepod: AAS_4100_Toxicity_Copepods 3. gastropod: AAS_2933_MetaToxicityMarine_JuvenileGastropods_Kingston2007 4. ostracod: AAS_2933_MetalToxicityMarine_BrownOstracods_Kingston2007 Subset details are described in the excel file provided.

  • Two toxicity tests were conducted in the Davis station laboratories in December 2010. Tests used locally collected amphipods of the species Orchomenella pinguides. The tests were conducted by Bianca Sfiligoj, as part of her PhD research (Sfiligoj 2013), with results published in (Sfiligoj et al. 2015). Field and laboratory work was conducted under project AAS 2933, with analysis and write-up completed under AAS 4100 (both projects CI: King). Details are fully described in the published manuscript provided with this data record; file name: Sfiligoj et al 2015_Ecotoxicology.pdf. A subset of the data is also used in Candy et al. 2015 (Filename: Candy et al 2015_Ecotoxicology.pdf). Data files: Test data are provided in the .xlsx file: 'Orchomenella-Tests-Dec 2010.xlsx'. Each worksheet includes a "This worksheet provides…" description in cell A1. Laboratory notebook records are provided in the scanned file: Sfiligoj-LabBookScan-Davis10-11.pdf. In this notebook, tests are labelled LT1 and LT2 (referred to as: amphipod lentil test 1 and 2); with results recorded on pages: 1-19 and 26-28. Data associated with this record has also been presented at: - Candy SG, Sfiligoj BJ, King CK, Mondon JA (2013) Modelling interval-censored survival times in toxicological studies using generalized additive models, The International Biometric Society Australasian Region Conference 2013, Mandurah, Australia, 1-5 December 2013. - Sfiligoj BJ, King CK, Candy SG, Mondon JA (2012) Development of appropriate bioassay and statistical methods for determining survival sensitivities of Antarctic marine biota to metal exposure, 2nd Society for Environmental Toxicology and Chemistry (SETAC) Australasia Conference, Brisbane, Australia, 4-6 July 2012. - Sfiligoj BJ, King CK, Candy SG, Mondon JA (2012) Development of appropriate bioassay and statistical methods for determining survival sensitivities of Antarctic marine biota to metal exposure, Society for Environmental Toxicology and Chemistry (SETAC) World Congress, Berlin, Germany, 20-24 May 2012.

  • This metadata record contains the results from bioassays conducted to show the response of the common Antarctic amphipod, Paramoera walkeri to contamination from combinations of Special Antarctic Blend (SAB) diesel, Marine Gas Oil (MGO) and Intermediate Fuel Oil (IFO 180), chemically dispersed with fuel dispersants Ardrox 6120 and Slickgone NS. Fuel only water accommodated fractions (WAF), chemically enhanced water accommodated fractions (CEWAF) and dispersant only treatments were prepared following the methods in Singer et al. (2000) with adaptations from Barron and Ka’aihue (2003). WAF was made using the ratio of 1: 25 (v/v), fuel to filtered seawater (FSW) following the methods of Brown et al. (in prep). Ratios for chemically dispersed treatments were 1: 100 (v/v), fuel to FSW and 1: 20 (v/v) dispersant to fuel. Dispersant only treatments were made using ratios for CEWAF, substituting the fuel component with FSW. Mixes were made in 5 L or 10 L glass aspirator bottles using a magnetic stirrer to achieve a vortex of 20-25% in the FSW before the addition of test media. The same mixing energy was used to prepare all WAFs for enhanced reproducibility and comparability of results (Barron and Ka’aihue, 2003). Mixes were stirred in darkness to prevent bacterial growth for 42 h with an additional settling time of 6 h at 0 plus or minus 1 oC. Extended stirring times were used following the recommendations determined as part of the hydrocarbon chemistry component of this project (Kotzakoulakis, unpublished data). A dilution series of four concentrations were made from the full strength aqueous phase of each mix using serial dilution. WAF test concentrations were 100%, 50%, 20% and 10% while CEWAF concentrations were 10%, 5%, 1% and 0.1%. These concentrations were chosen in order to quantify the mortality curve and allow statistical calculation of LC50 values. To facilitate comparisons of dispersant toxicity in the presence and absence of fuel, dispersant only test concentrations reflected those of CEWAF treatments. WAF was sealed in airtight glass bottles stored at 0 plus or minus 1 oC for a maximum of 3 h before use. Fresh test solutions were prepared every four days to ensure consistent water quality and replace hydrocarbons that adsorbed or evaporated into the atmosphere. Each test concentration was represented by five replicates with five FSW control beakers, with 10 P. walkeri individuals per replicate. Only healthy and active individuals were chosen with a size range of 7.9 plus or minus 0.7 mm for adults and 2.5 plus or minus 0.2 for juveniles measured from the base of the antennae to the widest part of the dorsal curve. Larger individuals and brooding females were not used to avoid unrelated deaths related to age or reproductive state (Sagar, 1980). Beakers were filled to 200 ml and were left open to allow the natural evaporation of lighter monoaromatic hydrocarbon components that would occur during a real spill. A small square of plankton mesh was placed in each jar to provide a substratum to reduce the stress of laboratory conditions and to help to stem cannibalism. Animals were not fed during experiments to avoid hydrocarbons adsorbed onto food pellets being ingested by the amphipods, thereby introducing an additional exposure pathway. Experiments ran for a total of 12 d exposure duration. Experiments were run in cold temperature-controlled cabinets maintained at a temperature of 0 plus or minus 1 oC, fluorescent lights in the cabinets were set to a light regime of 18 h light, 6 h darkness, following the methods in Brown et al. (2017) to reflect Antarctic summer environmental conditions. Lethal and sublethal observations were made at standard ecotoxicology test times of 24 h, 48 h, 96 h, 7 d, 10 d and 12 d, with an additional observation at 8 d coinciding with one of the 4-day water changes. The health status of each individual was classified on a scale of one to four; one showing no effect up to four being mortality. Mortality was determined by a lack of movement and response to stimuli, particularly in the gills. Dead animals were removed and preserved in 80% ethanol at each observation period. Missing amphipods that may have been cannibalised were included in mortality counts as they were likely to have been moribund or already dead when eaten. In order to simulate a repeated pulse pollutant, 90 to 100% of the test solution volume of each beaker was renewed with freshly made test concentrations every four days to replenish hydrocarbons lost through evaporation and adsorption and ensure consistent water quality. Beakers were topped up to 200 ml between water changes with deionised water to maintain water quality parameters. Duplicate 25 ml aliquots of test concentrations were taken at the beginning and end of each experiment in addition to pre and post water change samples. Samples were immediately extracted with 0.7 μm of dichloromethane spiked with an internal standard of BrC20 (1-bromoeicosane) and cyclooctane. Samples were analysed using Gas Chromatography with Flame Ionisation Detection (GC-FID) and mass spectrometry (GC-MS). To determine actual exposure concentrations, four day measured TPH values were used to create a continuous exposure and evaporation profile over the 12 d test period following the methods outlined in Payne et al. (2014) and Brown et al. (2017).

  • This metadata record contains the results of bioassays conducted to characterise the response of Antarctic nearshore marine invertebrates to hydrocarbon contaminants in fuels commonly used in Antarctica. AAS Project 3054. The results of Season 2 and Season 3 amphipod tests are in this dataset. Ecotoxicological bioassays were conducted at Davis and Casey Stations in 2009/10, 2010/11 and 2011/12 summer seasons to test the sensitivity of marine invertebrates to fuels in seawater. The three fuel types used in this project were: Special Antarctic Blend diesel (SAB), Marine Gas Oil diesel (MGO) and an intermediate grade (180) of marine bunker Fuel Oil (IFO). Test treatments were obtained by experimentally mixing fuel and seawater in temperature control cabinets at -1 degrees 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 1:25 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. This dataset contains the results of ecotoxicological bioassays with near-shore marine amphipod species exposed to WAFs of SAB WAF, MGO WAF and IFO WAF (specified above). Experimental treatments consisted of undiluted 100% WAF and dilutions of 10% and 1% of WAFs in FSW, to test the toxicity of water accommodated fractions of these three fuels on Antarctic marine invertebrates. The majority of experiments tested WAFs of each of the three fuels, although one tested SAB only due to limited supply of test organisms. Bioassays were conducted in open vessels (glass jars or beakers) in temperature controlled cabinets. Mortality and/or sub-lethal effects were observed at endpoints of 24 h, 48 h, 96 h, 7 d, 8 d, 10 d, 12 d, 14 d, 16 d and 21 d. New WAF solutions were prepared at 4 d intervals 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. Hydrocarbon concentrations in WAFs were determined from replicate experiments to measure THC in WAFs over time (Dataset AAS_3054_THC_WAF). WAF exposure concentrations for each bioassay endpoint were derived from these hydrocarbon tests. An integrated concentration was calculated from measured hydrocarbon concentrations weighted to time. Calculations account for depletion of hydrocarbons from test treatments and any renewal of treatments. These integrated THC concentrations for endpoints from 24h to 21d are contained in dataset AAS_3054_THC_WAF_integ_conc_10_11_12. This dataset consists of Excel spreadsheets. The file name code for invertebrate bioassays is; Project number_Season_Taxa_Test name Eg AAS_3054_10_11_amphipod_2PWA1 Project number : AAS_3054 Season : 2010/11 season Taxa: amphipod Test name:2 for Season 2, PW for genus and species, A for adult, 1 for Test 1 Bioassay spreadsheets contain the results of bioassays for a species. Where replicate tests were conducted, each experiment is on a separate spreadsheet. The worksheet labelled "Test conditions" shows details of Test name, dates, animal collection details, laboratory holding conditions, details of water accommodated fractions (WAF), bioassay conditions, scoring criteria and water quality data. The worksheet labelled "Counts" has columns for Replicate number and columns with the Score for all the animals in that replicate at every time endpoint. A full description of the scoring criteria is on the "Test conditions" worksheet. Totals, means and standard deviations are calculated for each treatment. The worksheet labelled "Totals, means, percent, StDev" has calculations of Survival, Unaffected, including mean and standard deviation, Percent Survival and Unaffected including means and standard deviation. Also included is column for the Total number of moults in each treatment. During the research to obtain early life stages of invertebrates for experiments, the number of Paramoera walkeri amphipod neonates per female, the timing of their release from the brood pouch and their early growth rate were recorded. These data are also included in AAS_3054_10_11_PW_neonates Samples were collected from: Ellis Narrows, Vestfold Hills Airport Beach, Davis, Vestfold Hills Prydz Bay, Davis (Between Anchorage Island and Bluff Island) Bailey Peninsula, Windmill Islands

  • Overview The aim of the project was to assess the genetic connectivity of benthic amphipods (crustaceans) on a circumantarctic scale. Two sibling amphipod species were chosen as the subjects for this study: Eusirus perdentatus and Eusirus giganteus. Samples of both species were collected (or donated by other institutions) from five broad regions of the Antarctic coast (see 'Sample location information' worksheet). The dataset we generated represents DNA sequences we obtained from these amphipods. Each amphipod was sequenced for three gene regions - these were cytochrome oxidase subunit I (COI), internal transcribed spacer 2 (ITS2) and cytochrome b (CytB). Each DNA sequence generated has been deposited on the publicly-accessible GenBank website (www.ncbi.nlm.nih.gov/genbank/) and therefore has its own accession number (which can be typed into the GenBank search bar to access the actual DNA sequence in .fasta format). The attached spreadsheet provides details on the location, depth and date of each amphipod sample collected, the preliminary species ID for each amphipod*, and the resultant DNA sequences corresponding to each of the three gene regions amplified (these are provided as Genbank accession numbers). *Results of this project have actually highlighted that Eusirus perdentatus and Eusirus giganteus almost certainly contain several extra cryptic species, therefore these ID's are likely to be revised in the future. Data collection and analysis The full methodology used to generate and analyse the DNA sequences prior to their deposition on Genbank can be found in the associated publication (see below). Most amphipod samples were collected between January 2007 and January 2010. However, a small proportion of the samples were collected on Polarstern voyages that took place in February 2002 and December 2003-January 2004. Genetic data was generated and analysed between June 2008 and May 2010. Circumantarctic DNA sequences obtained from two amphipod species, Eusirus perdentatus and Eusirus giganteus - DNA sequences obtained from two sibling amphipod species, Eusirus perdentatus and Eusirus giganteus. Samples of both species were collected (or donated by other institutions) from five broad regions of the Antarctic coast: Tressler Bank, East Coast, Ross Sea, Antarctic Peninsula and Weddell Sea. Collection dates ranged from 2002 to 2010. Sample location information is included. Explanation of spreadsheet Worksheet: 'Samples and genetic data' This worksheet contains all of the actual data generated, although rather than providing entire genetic sequences, we provide the Genbank accession number which can be used to access the sequence online (as explained above). The column headings are as follows: Sample ID- a unique code given to each amphipod sample as a form of identity. Morphological ID- the species identification for each amphipod, as determined morphologically (i.e. the genetic data has since illuminated that these IDs may need revision in the future). Sampling site- a code for the exact location from which each amphipod was sampled. For details on these locations, refer to 'Sample location information' worksheet, which uses the same codes. DNA sequence (Genbank accession number)- Genbank accession numbers for the DNA sequences obtained from each amphipod. The three columns within this represent the three gene regions we sequenced: COI (cytochrome oxidase subunit I), CytB (cytochrome b) and ITS2 (internal transcribed spacer 2). Occasionally one of these gene regions would fail to amplify in a particular sample, or the sequence was ambiguous, therefore not all amphipod samples have an accession number for all three gene regions. Worksheet: 'Sample location information' This worksheet provides the details on the actual collection of the amphipod specimens. Column headings are as follows: Sampling site- the code for each site from which amphipods were sampled, as used in the previous worksheet. Latitude- coordinates for each sampling site. Longitude- coordinates for each sampling site. Depth range of trawl (m)- As all amphipod samples were collected in benthic trawls deployed from research vessels, this column provides the depth range of the seabed over which each trawl was dragged. Collection date- the month and year in which each site was sampled. Region of Antarctic coast- the broad geographic region of the Antarctic coastline into which each set of sampling sites is grouped. Research vessel- the research vessel from which benthic trawls were deployed to collect the amphipods at each site. Note that for each broad geographic region, a single vessel was responsible for collecting all samples.

  • 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.

  • Ecotoxicological tests were done at Davis and Casey Stations in 2009/10, 2010/11 and 2011/12 summer seasons under AAS Project 3054 to test the sensitivity of near-shore marine invertebrates to fuels in seawater. The three fuel types used in this project were: Special Antarctic Blend diesel (SAB), Marine Gas Oil diesel (MGO) and an intermediate grade (180) of marine bunker fuel oil (IFO). This dataset contains the results of tests with the near-shore amphipod species Paramoera walkeri exposed to WAFs of SAB, MGO and IFO 180 (specified below) conducted at Davis Station in 2009/10 summer (Season 1). Test treatments were obtained by experimentally mixing fuel and seawater in temperature control cabinets at -1°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 1:40 fuel : FSW. This mixture was stirred at slow speed with minimal vortex on a magnetic stirrer. The water portion was then drawn from beneath the fuel. Test treatments consisted of undiluted 100% WAF and dilutions of 10% and 1% of WAFs in FSW. Toxicity tests were conducted in open glass vessels in temperature controlled cabinets. Mortality and/or sub-lethal effects were observed at endpoints of 24 h, 48 h, 96 h, 7 d, 14 d, and 21 d. Treatments were renewed at 7 d intervals. Water quality data was collected at each water change. Hydrocarbon concentrations in WAFs were determined from replicate experiments to measure THC in WAFs over time (Dataset AAS_3054_THC_WAF). WAF exposure concentrations for each test endpoint were derived from these hydrocarbon tests to account for depletion of hydrocarbons from test treatments and any renewal of treatments. An integrated concentration was calculated from measured hydrocarbon concentrations weighted to time. These integrated THC concentrations for endpoints from 24h to 21d are contained in dataset AAS_3054_THC_WAF_integrated_conc_09_10 and are the exposure concentrations used for analysis of sensitivity. Species tested; Paramoera walkeri amphipod; adults This dataset consists of Excel spreadsheets. The file name code for invertebrate tests is; Project number_Season_Taxa_Test name Eg AAS_3054_09_10_amphipod_1PWA1 Project number : AAS_3054 Season : 2009/10 season Taxa: amphipod Test name: 1 for Season 1, PW for genus and species, A for adult, 1 for Test 1 Spreadsheets contain the results of tests with this species. Where replicate tests were conducted, each experiment is on a separate spreadsheet. The worksheet labelled 'Test conditions' shows details of Test name, dates, animal collection details, laboratory holding conditions, details of water accommodated fractions (WAF), test conditions, scoring criteria and water quality data. The worksheet labelled 'Counts' has columns for Replicate number and columns with the Score for all the animals in that replicate at every time endpoint. A full description of the scoring criteria is on the 'Test conditions' worksheet. Totals, means and standard deviations are calculated for each treatment. The worksheet labelled 'Totals, means, percent, StDev' has calculations of Survival, Unaffected, including mean and standard deviation, Percent Survival and Unaffected including means and standard deviation. Amphipod tests also show the Total number of moults in each treatment. Samples were collected at the following locations: - Airport Beach, Davis, Vestfold Hills

  • This record describes the collection of marine fauna sampled from coastal areas of the Vestfold Hills in 1999. The project was undertaken to compile morphometric data on Weddell seal prey species. Benthic prawns i.e. Chorismus antarcticus and Notocrangon antarcticus, are common Weddell prey species at the Vestfold Hills. We fished for prawns using mesh traps (40 x 20 x 20 cm3). The traps were set at Magnetic Island in May, and in Ellis Fjord in December. The site near Magnetic Island was chosen when the fast-ice fractured enabling the gear to be set in natural tracts of open water. The site in Ellis Fjord was chosen on the basis of published information regarding bathymetry and the range of depths inhabited by prawn species. We waited until December to sample in Ellis Fjord so that the fishing hole did not refreeze. Prawns were caught only in Ellis Fjord and only when the traps were deployed open i.e. with zips on the doors to get the catch out left undone. Approximately 50 prawns of various sizes were caught over three days at the same location, 200 m east of the crossing at Ellis Narrows. The catch has been stored whole in the Australian Antarctic Division freezer in Hobart. Bycatch included amphipods and Notothenid fish at Magnetic Island, and echinoderms, holothurians and Notothenid fish in Ellis Fjord. Some of the bycatch were retained and are stored frozen with the prawns. The linked dataset contains the measurements of length, mass, carapace length and sex (juvenile, male, female) of the prawn catch. All of the prawns were Chorismus antarcticus. The adult females were brooding eggs. The best fit linear regressions were y = 0.3529x - 2.4824, (R2 = 0.9504) for carapace length to predict body mass, and y = 3.5267x + 4.5846 (R2 = 0.9544) for carapace length to body length. The associated URLs contain all of the data, including spreadsheet of data, a scatterplot of the length mass relationship, and a mass frequency histogram of the catch. The fields in this dataset are: Chorismus ID carapace length (mm) body length (mm) mass (g) sex

  • 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.