Metadata record for data from ASAC Project 1119 See the link below for public details on this project. A marked bend in the Hawaiian-Emperor seamount chain supposedly resulted from a recent major reorganization of the plate-mantle system there 50 million years ago. Although alternative mantle-driven and plate-shifting hypotheses have been proposed, no contemporaneous circum-Pacific plate events have been identified. We report reconstructions for Australia and Antarctica that reveal a major plate reorganization between 50 and 53 million years ago. Revised Pacific Ocean sea-floor reconstructions suggest that subduction of the Pacific-Izanagi spreading ridge and subsequent Marianas/Tonga-Kermadec subduction initiation may have been the ultimate causes of these events. Thus, these plate reconstructions solve long-standing continental fit problems and improve constraints on the motion between East and West Antarctica and global plate circuit closure.

In January 2005 a multi-parametric international experiment was conducted that encompassed both Deception Island and its surrounding waters. This experiment used as main platforms the Spanish Oceanographic vessel 'Hesperides', the Spanish Scientific Antarctic base 'Gabriel de Castilla' at Deception Island and four temporary camps deployed on the volcanic island. This experiment allowed us to record active seismic signals on a large network of seismic stations that were deployed both on land and on the seafloor. In addition other geophysical data were acquired, such as: bathymetric high precision multi-beam data, and gravimetric and magnetic profiles. During the whole period of the experiment a multi-beam sounding EM120 was used to perform bathymetric surveys. The characteristic of this sensor permitted to reach up to 11.000 m b.s.l. In table 2 we provide some of its main characteristics. During the experiment different bathymetric profiles were performed with this equipment outside of Port Foster. Some of these images already have provide an accurate vision of the region, and were used to estimate the real size of the water column locate below each shoot. Additional information of these data could be found in the Lamont-Doherty Earth Observatory at IEDA Marine Geoscience Data System (http://www.marine-geo.org/). It is possible to access the summary of downloads that were made of these data and documents at http://www.marine-geo.org/about/downloadreport/person/Ibanez_Jesus/2016A.

Acoustic depth soundings are routinely collected on Australian Antarctic Division voyages. This metadata record links to child records which describe processed soundings datasets from voyages since 1985. Documentation is included with the datasets.

A high resolution bathymetric grid of the nearshore area at Casey station, Antarctica was produced by Geoscience Australia by combining data from two multibeam hydrographic surveys: 1) A survey conducted by the Royal Australian Navy in 2013/14. Refer to the metadata record 'Hydrographic survey HI545 by the RAN Australian Hydrographic Service at Casey, December 2013 to January 2014' with ID HI545_hydrographic_survey. 2) A survey conducted by Geoscience Australia and the Royal Australian Navy in 2014/15. Refer to the metadata record 'Hydrographic survey HI560 by the RAN Australian Hydrographic Service at Casey, December 2014 to February 2015' with ID HI560_hydrographic_survey and the metadata record 'Seafloor Mapping Survey, Windmill Islands and Casey region, Antarctica, December 2014 - February 2015' with ID AAS_3326_seafloor_mapping_casey_2014_15. The grid has a cell size of one metre and is stored in a UTM Zone 49S projection, based on WGS84. Further information is available from the Geoscience Australia website (see a Related URL).

The Davis Coastal Seabed Mapping Survey, Antarctica (GA-4301 / AAS2201 / HI468) was conducted on the Australian Antarctic Division workboat Howard Burton during February-March 2010 as a component of Australian Antarctic Science (AAS) Project 2201 - Natural Variability and Human Induced Change on Antarctic Nearshore Marine Benthic Communities. The survey was undertaken as a collaboration between Geoscience Australia, the Australian Antarctic Division and the Australian Hydrographic Service (Royal Australian Navy). The survey acquired multibeam bathymetry and backscatter datasets from the nearshore region of the Vestfold Hills around Davis Station, Antarctica. These datasets are described by the metadata record with ID Davis_multibeam_grids. This dataset comprises an interpreted geomorphic map produced for the central survey area using multibeam bathymetry and backscatter grids and their derivatives (e.g. slope, contours). Six geomorphic units; basin, valley, embayment, pediment, bedrock outcrop and scarp were identified and mapped using definitions suitable for interpretation at the local scale (nominally 1:10 000). Polygons were created using a combination of automatic extraction and manual digitisation in ArcGIS. For further information on the geomorphic mapping methods and a description of each unit, please refer to OBrien P.E., Smith J., Stark J.S., Johnstone G., Riddle M., Franklin D. (2015) Submarine geomorphology and sea floor processes along the coast of Vestfold Hills, East Antarctica, from multibeam bathymetry and video data. Antarctic Science 27:566-586. This metadata record was created using information in Geoscience Australia's metadata record at http://www.ga.gov.au/metadata-gateway/metadata/record/89984/

The geomorphology was digitised using contours derived from the DEM created by Dr. R. Beaman from James Cook University for Geoscience Australia. The data, the metadata record and the report related to the creation of that DEM are available on the Geoscience Australia website: Name of data set: Kerguelen Plateau Bathymetric Grid 2010 Catalogue number: 71552 https://ecat.ga.gov.au/geonetwork/srv/eng/catalog.search?node=srv#/metadata/a05f7893-007f-7506-e044-00144fdd4fa6 Digitising: It must be stressed that neither seismic data, sea floor sediments, nor sea floor biota were used to determine the sea floor geomorphology. The description on how the geomorphology was derived is described in the attached report. The features described as slopes from the 900m to 1300m isobaths and from the 1300m to 2500m isobaths were identified for fisheries purposes and not geomorphology purposes. A geomorphologist may combine these slopes into a single feature. Some of the larger shallow features identified as banks may more properly be identified as plateaus. It would require a more in depth analysis of the DEM, slopes and sediments to accurately identify the feature as a bank or plateau.

This dataset consists of underway data, including bathymetric data, collected aboard Australian Antarctic Division research vessels between 1985 and 2012. The data are available in csv format and the raw SIMRAD format. In the csv files bathymetric data is in the WTR_DEPTH_M column. Some voyages will not have bathymetric data associated with them. The csv data may have been quality checked. Most of the underway data was quality checked ('dot zapped') up to and including voyage 4 2003/04. Data quality reports are available by searching at http://data.aad.gov.au/aadc/voyages/ Other than on Marine Science voyages, the Aurora Australis bathymetric data gathering procedures prior to about 2000 were not checked during the voyage. The echo sounder was turned on in Hobart and if it stopped working during the voyage, then there was no one to get it going again. Bathymetric data from these voyages that has been processed by the Royal Australian Navy is available via other metadata records linked to the parent record with ID AAD_voyage_soundings.

This project exploited the unique exposures of the uppermost oceanic crust found on Macquarie Island as a window into the internal structure of the oceanic crust. The form of rock units and the way in which they are arranged on the Island provided a means of understanding how they were assembled. This assembly occurred beneath a mid-ocean ridge spreading center, an area that can probably never be directly investigated. The general process by which this crust has formed is responsible for the creation of about 60% of the bedrock geology of the Earth. The Macquarie Island ophiolite is an uplifted block of oceanic crust formed at the Australia-Pacific spreading centre between 12 and 9 Ma. The sense of motion and geological processes across this plate boundary reflect an evolution from orthogonal spreading through progressively more oblique spreading to the present-day transpressional regime. The crust that makes up the island was formed during an interval of oblique spreading along east-trending spreading segments punctuated by a series of northwest-trending discontinuities. The discontinuities are accommodation zones marked by oblique-slip dextral-normal faults, localised dikes and lava flows, and extensive hydrothermal alteration, indicating that these zones were active near the spreading axis. These features provide a window into the internal structure of oceanic crust generated by oblique spreading. The download file contains: I. Publication folder (PDF files): 1. Alt, J.C., G. Davidson, D.A.H. Teagle and J.A. Karson, The isotopic composition of gypsum in the Macquarie Island Ophiolite: Implications for sulfur cycle and the subsurface biosphere in oceanic crust, Geology, 31, 549-552, 2003. 2. Rivizzigno, P.A. and J.A. Karson, Mid-ocean ridge fault zones preserved on Macquarie Island: Faulting, hydrothermal processes and magmatism in an oblique-spreading environment, Geology 32, 125-128, 2004. 3. Rivizzigno, P. A., The Major Lake Fault Zone: An Oblique Spreading Structure Exposed in the Macquarie Island Ophiolite, Southern Ocean, MS Thesis, Duke University, Durham, NC USA, 2002, 59 pp. II. Macca Maps folder (TIFF files): 1. Helicopter Video: Macca map showing the path and view direction from a video made during a helicopter trip over the island in 2000 during an unusually clear day. Copies of the video were left with ANARE and with various people at UTas (R. Varne, G. Davidson and others). 2. JAK2000Samples: Macca map with locations of samples collected by J.A. Karson during the 2000 field season. Samples are numbered MAC00-XX. Samples are under study at Duke University. 3. JAKMK2000Samples: Macca map with locations of samples of dike rocks collected for geochemicial studies by J.A. Karson during the 2000 dield season. Samples are numbered MK-XX. They were left with Dr. R. Varne (UTas) in 2000. 4. PAR2000Samples: Macca map with locations of samples collected by P.A. Rivizzigno during the 2000 field season. Samples are under study at Duke University and reported in Rivizzigno (2002) and Rivizzigno and Karson (2004). 5. PARMK2000: Macca map with locations of samples of dike rocks collected for geochemicial studies by J.A. Karson during the 2000 dield season. Samples are numbered MK-XX. They were sent to Dr. R. Varne (UTas) in 2000. 6. Geological map from Rivizzigno (2002) in vector art (Canvas 8.0) and bitmap (jpeg) formats. New data are plotted on a base map by Goscombe and Everard (1998). III. Other Information folder (WORD files): 1. References: citations of journal articles, theses, abstracts from this project. 2. JAK Sample Log: List of samples, locations, etc. for Karson samples from 2000.

This dataset comprises Digital Elevation Models (DEMs) of varying resolutions for the George V and Terre Adelie continental margin, derived by incorporating all available singlebeam and multibeam point depth data into ESRI ArcGIS grids. The purpose was to provide revised DEMs for Census of Antarctic Marine Life (CAML) researchers who required accurate, high-resolution depth models for correlating seabed biota data against the physical environment. The DEM processing method utilised all individual multibeam and singlebeam depth points converted to geographic xyz (long/lat/depth) ASCII files. In addition, an ArcGIS line shapefile of the East Antarctic coastline showing the grounding lines of coastal glaciers and floating ice shelves, was converted to a xyz ASCII file with 0 m as the depth value. Land elevation data utilised the Radarsat Antarctic Mapping Project (RAMP) 200 m DEM data converted to xyz ASCII data. All depth, land and coastline ASCII files were input to Fledermaus 3DEditor visualisation software for removal of noisy data. The cleaned point data were then binned into a gridded surface using Fledermaus DMagic software, resulting in a 0.001-arcdegree (~100 m) resolution DEM with holes where no input data exists. ArcGIS Topogrid software was used to interpolate across the holes to output a full-coverage DEM. ArcGIS was used to produce the additional 0.0025-arcdegree (~250 m) and 0.005-arcdegree (~500 m) resolution grids. Full processing details can be viewed in: Beaman, R.J., O'Brien, P.E., Post, A.L., De Santis, L., 2011. A new high-resolution bathymetry model for the Terre Adelie and George V continental margin, East Antarctica. Antarctic Science 23(1), 95-103. doi:10.1017/S095410201000074X

In September 2006, twenty-three scientists from six countries attended an Experts Workshop on Bioregionalisation of the Southern Ocean held in Hobart, Australia. The workshop was hosted by the Antarctic Climate and Ecosystems Cooperative Research Centre, and WWF-Australia, and sponsored by Antarctic expedition cruise operator, Peregrine Adventures. The workshop was designed to assist with the development of methods that might be used to partition the Southern Ocean for the purposes of large-scale ecological modelling, ecosystem-based management, and consideration of marine protected areas. The aim of the workshop was to bring together scientific experts in their independent capacity to develop a 'proof of concept' for a broad-scale bioregionalisation of the Southern Ocean, using physical environmental data and satellite-measured chlorophyll concentration as the primary inputs. Issues examined during the workshop included the choice of data and extraction of relevant parameters to best capture ecological properties, the use of data appropriate for end-user applications, and the relative utility of taking a hierarchical, non-hierarchical, or mixed approach to regionalisation. The final method involved the use of a clustering procedure to classify individual sites into groups that are similar to one another within a group, and reasonably dissimilar from one group to the next, according to a selected set of parameters (e.g. depth, ice coverage, temperature). The workshop established a proof of concept for bioregionalisation of the Southern Ocean, demonstrating that this analysis can delineate bioregions that agree with expert opinion at the broad scale. Continuation of this work will be an important contribution to the achievement of a range of scientific, management and conservation objectives, including large-scale ecological modelling, ecosystem-based management and the development of an ecologically representative system of marine protected areas. This metadata record provides links to the report from that workshop, the appendices to that report, and the ArcGIS files and Matlab code used during the workshop. The report is in PDF format. The Appendices to the report are in PDF format and contain: Appendix 1: Approaches to bioregionalisation - examples presented during the workshop Antarctic Environmental Domains Analysis CCAMLR Small-Scale Management Units for the fishery Antarctic krill in the SW Atlantic Australian National Bioregionalisation: Pelagic Regionalisation Selecting Marine Protected Areas in New Zealand's EEZ Appendix 2: Technical information on approach to bioregionalisation Appendix 3: Descriptions of datasets used in the analysis Appendix 4: Results of secondary regionalisation using ice and chlorophyll data Appendix 5: Biological datasets of potential use in further bioregionalisation work Appendix 6: Details of datasets, Matlab code and ArcGIS shapefiles included on the CD The ArcGIS archive is in zip format and contains the shapefiles and other ArcGIS resources used to produce the figures in the report. The Matlab archive is in zip format and contains the Matlab code and gridded data sets used during the workshop. See the readme.txt file in this archive for more information. Description of datasets Sea surface temperature (SST) Mean annual sea surface temperatures were obtained from the NOAA Pathfinder satellite annual climatology (Casey and Cornillon 1999). This climatology was calculated over the period 1985-1997 on a global 9km grid. Monthly values were averaged to obtain an annual climatology. Casey, K.S. and P. Cornillon (1999) A comparison of satellite and in situ based sea surface temperature climatologies, J. Climate, vol. 12, no. 6, pp. 1848-1863. Bathymetry Depth data were obtained from the GEBCO digital atlas (IOC, IHO and BODC, 2003). These data give water depth in metres and are provided on a 1-minute global grid. Centenary Edition of the GEBCO Digital Atlas, published on CD-ROM on behalf of the Intergovernmental Oceanographic Commission and the International Hydrographic Organization as part of the General Bathymetric Chart of the Oceans, British Oceanographic Data Centre, Liverpool, U.K. See http://www.gebco.net and https://www.bodc.ac.uk/projects/data_management/international/gebco/ A metadata record can be obtained from: http://data.aad.gov.au/aadc/metadata/metadata_redirect.cfm?md=AMD/AU/gebco_bathy_polygons Nutrient concentrations Silicate and nitrate concentrations were obtained from the WOCE global hydrographic climatology (Gouretski and Koltermann, 2004). This climatology provides oceanographic data on a 0.5 degree regular grid on a set of 45 standard levels covering the depth range from the sea surface to 6000m. The silicate and nitrate concentrations were calculated from seawater samples collected using bottles from stationary ships. The nutrient concentrations at the 200m depth level were used here; concentrations are expressed in micro mol/kg. https://odv.awi.de/data/ocean/woce-global-hydrographic-climatology/ Gouretski, V.V., and K.P. Koltermann, 2004: WOCE Global Hydrographic Climatology. Technical Report, 35, Berichte des Bundesamtes fur Seeschifffahrt und Hydrographie. Insolation (PAR) The mean summer climatology of the photosynthetically-active radiation (PAR) at the ocean surface was obtained from satellite estimates (Frouin et al.). These PAR estimates are obtained from visible wavelengths and so are not available over cloud- or ice-covered water, or in low-light conditions including the austral winter. Hence in the sea ice zone, this climatology represents the average PAR calculated over the period for which the water was not ice-covered. https://oceancolor.gsfc.nasa.gov/cgi/l3 Robert Frouin, Bryan Franz, and Menghua Wang. Algorithm to estimate PAR from SeaWiFS data Version 1.2 - Documentation. Chlorophyll-a Mean summer surface chlorophyll-a concentrations were calculated from the SeaWiFS summer means. We used the mean of the 1998-2004 summer values. Chlorophyll concentrations are expressed in mg/m^3. https://oceancolor.gsfc.nasa.gov/cgi/l3 Sea ice We calculated the mean fraction (0-1) of the year for which the ocean was covered by at least 15% sea ice. These calculations were based on satellite-derived estimates of sea ice concentration spanning 1979-2003. http://nsidc.org/data/nsidc-0079.html Comiso, J. (1999, updated 2005). Bootstrap sea ice concentrations for NIMBUS-7 SMMR and DMSP SSM/I. Boulder, CO, USA: National Snow and Ice Data Center. Digital media. Southern Ocean Fronts These are the front positions as published by Orsi et al. (1995). Orsi A, Whitworth T, III, Nowlin WD, Jr (1995) On the meridional extent and fronts of the Antarctic Circumpolar Current. Deep-Sea Research 42:641-673 Use of these data are governed by the following conditions: 1. The data are provided for non-commercial use only. 2. Any publication derived using the datasets should acknowledge the Australian Antarctic Data Centre as having provided the data and the original source (see the relevant metadata record listed in the description below for the proper citation).