IMAS Metadata Catalogue
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At the inception of our project, no study had examined particle fluxes in the Subantarctic Zone (SAZ) of the Southern Ocean, despite the fact that the SAZ represents a large portion of the total area of the Southern Ocean, serve as a strong sink for atmospheric (~1G t C yr-1 [Metzl et al., 1999]), and is central to hypotheses linking particle fluxes and climate change [Francois et al., 1997; Kumar et al., 1995; Sigman et al., 1999]. The SAZ serves as an interface between the cold nutrient-rich waters to its south and the nutrient-depleted subtropical gyres to its north. SAZ upper layers are marked by a thick layer of relatively homogenous Subantarctic Mode Water (SAMW), which overlies Antarctic Intermediate Water (AAIW). Both water masses are subducted northward beneath the subtropical gyres. Thus particles leaving the surface in these regions contribute to carbon redistribution via both the fraction that reaches the deep sea by settling and the fraction that is remineralized within SAMW or AAIW and subsequently subducted. The SAZ exhibits surface water carbon dioxide partial pressures well below atmospheric equilibrium, but PFZ waters are closer to atmospheric equilibrium in this sector [Metal et al., 1999; Poppet al., 1999]. The relative physical and biological contributions to these carbon dioxide partial pressure variations are unclear, but it is important to determine them because physical and biological carbon dioxide transfers are expected to show different responses to climate change [ Matear et al., 1999; Sarmiento and LeQuere, 1996]. For these reasons we focused on the SAZ and, for comparative purposes, on the PFZ to its south. We measured particle fluxes using moored sinking particle traps at three sites in the SAZ, in the PFZ, and beneath the Subantarctic Front (SAF), which separates them. This record describes particle flux data collected between 2000 and 2001. The NetCDF data contains the following variables. Please note not all variables are supplied in all files, specifically there are not uncertainty estimates and no quality control flags for this data. -----DATA DICTIONARY----- Name, description, units, standard name TIME, time, YYYY-MM-DD, time of sample midpoint TIME_START, time sample open, YYYY-MM-DD, time sample open NOMINAL_DEPTH, depth, m, nominal depth LATITUDE, latitude, degrees_north, latitude of anchor LONGITUDE, longitude, degrees_east, longitude of anchor pressure_actual, actual, dbar, actual pressure sample, sample number, 1, sample number sample_quality_control, quality flag for sample number, unitless, quality flag for sample number mass_flux, <1mm, mg m-2 d-1, particulate total mass flux mass_flux_uncertainty, uncertainty for particulate total mass flux, mg m-2 d-1,), uncertainty for particulate total mass flux mass_flux_quality_control, quality flag for particulate total mass flux, unitless, quality flag for particulate total mass flux SAL_BRINE, supernatant, 1, sample supernatant practical salinity SAL_BRINE_uncertainty, uncertainty for sample supernatant practical salinity, 1, uncertainty for sample supernatant practical salinity SAL_BRINE_quality_control, quality flag for sample supernatant practical salinity, unitless, quality flag for sample supernatant practical salinity pH_BRINE, supernatant, 1, sample supernatant pH NBS scale pH_BRINE_uncertainty, uncertainty for sample supernatant pH NBS scale, 1, uncertainty for sample supernatant pH NBS scale pH_BRINE_quality_control, quality flag for sample supernatant pH NBS scale, unitless, quality flag for sample supernatant pH NBS scale PC_mass_flux, <1mm, mg m-2 d-1, particulate total carbon mass flux PC_mass_flux_uncertainty, uncertainty for particulate total carbon mass flux, mg m-2 d-1, uncertainty for particulate total carbon mass flux PC_mass_flux_quality_control, quality flag for particulate total carbon mass flux, unitless, quality flag for particulate total carbon mass flux PN_mass_flux, <1mm, mg m-2 d-1, particulate total nitrogen mass flux PN_mass_flux_uncertainty, uncertainty for particulate total nitrogen mass flux, mg m-2 d-1, uncertainty for particulate total nitrogen mass flux PN_mass_flux_quality_control, quality flag for particulate total nitrogen mass flux, unitless, quality flag for particulate total nitrogen mass flux POC_mass_flux, <1mm, mg m-2 d-1, particulate organic carbon mass flux POC_mass_flux_uncertainty, uncertainty for particulate organic carbon mass flux, mg m-2 d-1, uncertainty for particulate organic carbon mass flux POC_mass_flux_quality_control, quality flag for particulate organic carbon mass flux, unitless, quality flag for particulate organic carbon mass flux PIC_mass_flux, <1mm, mg m-2 d-1, particulate inorganic carbon mass flux PIC_mass_flux_uncertainty, uncertainty for particulate inorganic carbon mass flux, mg m-2 d-1, uncertainty for particulate inorganic carbon mass flux PIC_mass_flux_quality_control, quality flag for particulate inorganic carbon mass flux, unitless, quality flag for particulate inorganic carbon mass flux BSi_mass_flux, <1mm, mg m-2 d-1, particulate biogenic silicon mass flux BSi_mass_flux_uncertainty, uncertainty for particulate biogenic silicon mass flux, mg m-2 d-1, uncertainty for particulate biogenic silicon mass flux BSi_mass_flux_quality_control, quality flag for particulate biogenic silicon mass flux, unitless, quality flag for particulate biogenic silicon mass flux TIME_END, time sample closed, YYYY-MM-DD, time sample closed Reference, citable reference DOI, DOI
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This resource includes backscatter data for Arafura Marine Park (Arafura Sea) collected by Geoscience Australia (GA) and the Australian Institute of Marine Science during the period 2 – 15 November 2020 on the RV Solander. The survey was undertaken as a collaborative project funded through the National Environmental Science Program Marine Biodiversity Hub, with co-investment by GA and AIMS. The purpose of the project was to build baseline information for benthic habitats in Arafura Marine Park that will support ongoing environmental monitoring within the North Marine Park Network as part of the 10-year management plan (2018-2028). Data acquisition for the project included multibeam bathymetry and backscatter for two areas (Money Shoal and Pillar Bank), seabed samples and underwater imagery of benthic communities and demersal fish. This backscatter dataset contains two 32-bit geotiff files of the backscatter mosaic for two survey areas produced from the processed EM2040C Dual Head system using the CMST-GA MB Process v15.04.04.0 (x64) toolbox software co-developed by the Centre for Marine Science and Technology at Curtin University and Geoscience Australia. A detailed report on the survey is provided in: Picard, K. Stowar, M., Roberts, N., Siwabessy, J., Abdul Wahab, M.A., Galaiduk, R., Miller, K., Nichol, S. 2021. Arafura Marine Park Post Survey Report. Report to the National Environmental Science Program, Marine Biodiversity Hub (https://www.nespmarine.edu.au/node/4505).
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These aerial survey data of southern right whales (Eubalaena australis) off southern Australia were collected in August 2018. Such annual flights in winter/spring between Cape Leeuwin (Western Australia) and Ceduna (South Australia) have now been conducted over a 26-year period 1993-2018. These surveys have provided evidence of a population trend of around 6% per year, and a current (at 2014) population size of approximately 2300 of what has been regarded as the 'western' Australian right whale subpopulation. With estimated population size in the low thousands, it is presumed to be still well below carrying capacity. No trend information is available for the 'eastern' subpopulation of animals occurring around the remainder of the southern Australian Coast, to at least as far as Sydney, New South Wales and the populations size is relatively small, probably in the low hundreds. A lower than expected 'western' count in 2015 gives weak evidence that the growth rate may be starting to show signs of slowing, though an exponential increase remains the best description of the data. If the low 2015 count is anomalous, future counts may be expected to show an exponential increase, but if it is not, modelling growth as other than simple exponential may be useful to explore in future.
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The seagrass dataset has been compiled by UNEP-WCMC in collaboration with Dr Frederick T. Short, University of New Hampshire, USA to show the global distribution of seagrass species. This dataset has been created from multiple sources and was used in the creation of the “World Atlas of Seagrasses”(2003). This polygon feature dataset is an update of the data used in the Atlas and is a unique data holding about the state of the world’s seagrasses. For a complete overview of global seagrass distribution this dataset should be displayed together with the associated point dataset. Both polygon and point datasets are available to download from this record.
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In this study, 34 fledgling Fairy Prions (Pachyptila turtur) recovered during a wreck event in south-eastern Tasmania in 2022 were examined for ingested plastics (number, mass, type, colour, and particle size) and body condition (e.g., wing chord length).
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This record provides an overview of the NESP Marine and Coastal Hub project "Mapping critical Australian sea lion habitat to assess ecological value and risks to population recovery". For specific data outputs from this project, please see child records associated with this metadata. -------------------- Populations of the endangered Australian sea lion have declined by >60% over the last 40 years. There is a marked uneven distribution in abundance and trends across the species range, suggesting that localised risk profiles from threats vary at small spatial scales. Fine scale differences in habitat use are thought to underpin these differences, yet knowledge about the species dependency on key habitats and their vulnerability to human impacts is limited. This project will deploy underwater cameras onto sea lions to identify and map their critical habitats, assess their ecological value and identify risks to populations. Results will improve our understanding of threats to sea lion populations and support future conservation actions to recover the species. Outputs • Tracking data from sea lion-deployed tags: location, depth, time, temperature, light, acceleration [dataset] • Timestamped video footage from sea lion-deployed cameras [dataset] • Final project report [written]
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Model output from a circumpolar realisation of the Regional Ocean Modelling System (ROMS). Model was run at a horizontal resolution of 1/4 degree and 31 vertical levels. Spatial domain was circumpolar out to 30 degrees South. Forcing comes from prescribed salt and heat fluxes based on a derived climatology from Tamura et al (2008). For open water regions the Tamura data is blended with open-water heat, salt and surface stress fluxes from a monthly NCEP2 climatology.
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Annual aerial surveys of southern right whales have been conducted off the southern Australian coast, between Cape Leeuwin (W.A.) and Ceduna (S.A.) over a 28 year period between 1993 and 2020, to monitor the recovery of this species following commercial whaling. We conducted an aerial survey of southern right whales between the 20th and 24th August 2020, to continue these annual series of surveys and inform the long-term population trend. The comparable count for the 2020 survey utilised the maximum count for each leg and incorporated a correction for the unsurveyed area between Head of the Bight to Ceduna due to the inability to cover whole survey as a result of COVID-19 restrictions between State borders. This resulted in 384 individuals, consisting of 156 cows accompanied by calves of the year and 72 unaccompanied adults. Of these, 126 images of individual whales have been selected for photo-identification matching. This is a significant decrease in overall sightings that has not been observed for over 13 years when compared to long term trend data for the population; last seen in 2007 (N = 286 individuals). The subsequent population estimate for the Australian ‘western’ subpopulation is 2,585 whales, which is also a significant decrease in estimated population size from 3,164 in 2019 to 2,585 in 2020. The extremely low number of unaccompanied adults (N = 68) had the greatest impact on the overall number of sightings in 2020, and is the lowest number sighted since 1993 (N = 47). Previous surveys in 2007 and 2015 have been noted as years of low whale counts that had been deemed anomalous years, although the low numbers from this survey questions this and may suggest the 3-year female breeding cycle is becoming more unpredictable. Considerable inter-annual variation in whale numbers, and cycles in population growth, makes it difficult to detect consistent and reliable changes in abundance from one year to the next, or even over longer periods of time. This severely inhibits our ability to identify immediate threats to the population and strongly supports continued annual population surveys.
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The predators of Centrostephanus rodgersii, were identified using remote video monitoring. Experiments were performed in two eastern Tasmanian regions, the Maria Island Marine Reserve (MIMR, 42° 35.26'S, 148° 3.03'E) and the Crayfish Point Research Reserve (CPRR, 42° 57.37'S, 147° 21.30'E). The impact of fishing on these predators, and ultimately on C. rodgersii, was examined by comparing survival of C. rodgersii on reefs inside no-take Marine Protected Areas (MPAs) (high predator biomass) relative to fished reefs (low predator biomass). The size-specific nature of predation interactions was examined in context of size-selective fishing pressures within the sea urchin's extended range.
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This resource includes bathymetry data for Elizabeth and Middleton Reef within Lord Howe Marine Park collected by Geoscience Australia during the period 31 January to 6 February 2020 on the Australian Maritime College vessel, TV Bluefin. The survey was undertaken as a collaborative project funded through the National Environmental Science Program Marine Biodiversity Hub, with the Institute for Marine & Antarctic Studies (University of Tasmania), NSW Department of Primary Industries, University of Sydney (Centre for Field Robotics) and Parks Australia. The purpose of the survey was to collect baseline information for benthic habitats within the National Park Zone (Middleton Reef) and Recreational Use Zone (Elizabeth Reef) of the marine park. These data will support ongoing environmental monitoring within the Temperate East Marine Park Network as part of the 10-year management plan (2018-2028). Data acquisition for the project included seabed mapping using multibeam sonar (Kongsberg EM 2040C HD, 300 kHz), seabed imagery acquisition by Autonomous Underwater Vehicle (AUV Sirius), sediment samples (grab) and imagery of demersal fish communities by baited remote underwater video (BRUV). This dataset comprises two bathymetry grids derived from multibeam sonar data gridded at 5 m spatial resolution, covering a combined area of 312 km2 including the transit. A detailed report on the survey is provided in: Carroll, A et al. 2020. Australian Marine Park Baseline and Monitoring Survey: Post Survey Report, Middleton and Elizabeth Reefs, Lord Howe Marine Park. Report to the National Environmental Science Program, Marine Biodiversity Hub. This dataset is not to be used for navigational purposes. This dataset is published with the permission of the CEO, Geoscience Australia