Alexandra L. Post

Alexandra L. Post
Geoscience Australia

About

67
Publications
26,331
Reads
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1,967
Citations
Citations since 2016
22 Research Items
1284 Citations
2016201720182019202020212022050100150200
2016201720182019202020212022050100150200
2016201720182019202020212022050100150200
2016201720182019202020212022050100150200
Additional affiliations
January 2002 - present
Geoscience Australia
Position
  • Marine Geoscientist

Publications

Publications (67)
Article
Perth Canyon is Australia's second largest submarine canyon, and its shelf-incising morphology contrasts with the more prolific slope-confined canyons that typify Australia's passive continental margin. The canyon has a sinuous course that extends 120 km from the shelf break (~180 m depth) to its fan at the foot of the continental slope (~4500 m)....
Article
Repeat multibeam mapping of two slope-confined canyons on the northwest Australian margin provides new understanding of the processes that are active in shaping these environments. The Cape Range and Cloates canyons initiate on the mid to lower continental slope but are now known to be connected to the shelf via small channels and gullies. Both can...
Article
Full-text available
Knowledge of life on the Southern Ocean seafloor has substantially grown since the beginning of this century with increasing ship-based surveys and regular monitoring sites, new technologies and greatly enhanced data sharing. However, seafloor habitats and their communities exhibit high spatial variability and heterogeneity that challenges the way...
Article
Full-text available
The seafloor beneath floating ice shelves accounts roughly a third of the Antarctic’s 5 million km2 of continental shelf. Prior to this study, our knowledge of these habitats and the life they support was restricted to what has been observed from eight boreholes drilled for geological and glaciological studies. The established theory of sub-ice she...
Preprint
Full-text available
Understanding past retreat of Antarctic ice margins provides valuable insight for predicting how ice sheets may respond to future environmental change. This study, based on high resolution multibeam bathymetry from the nearshore region of the Windmill Islands, East Antarctica, reveals a style of retreat that has been rarely observed on the Antarcti...
Article
Full-text available
The rapidly thinning Totten Glacier on the Sabrina Coast, East Antarctica, is the primary drainage outlet for ice within the Aurora Subglacial Basin, which could destabilize under the current atmospheric warming trend. There is growing need for direct geological evidence from the Sabrina Coast to frame late twentieth century Totten melting in the c...
Article
The continental slope and rise seaward of the Totten Glacier and the Sabrina Coast, East Antarctica features continental margin depositional systems with high sediment input and consistent along-slope current activity. Understanding their genesis is a necessary step in interpreting the paleoenvironmental records they contain. Geomorphic mapping usi...
Article
Full-text available
Reductions in the thickness and extent of Antarctic ice shelves are triggering increased discharge of marine-terminating glaciers. While the impacts of recent changes are well documented, their role in modulating past ice-sheet dynamics remains poorly constrained. This reflects two persistent issues; first, the effective discrimination of sediments...
Article
This study applies detailed seafloor bathymetry data and seafloor images to understand upper slope features and how these influence the distribution of seafloor biota on the East Antarctic margin. The East Antarctic slope on the Sabrina margin has been shaped by diverse processes related to repeated glaciation. Differences in the morphology of gull...
Article
Be isotopes are a useful tracer of sediment source and transport pathways but have not been widely tested in glacio-marine environments. We measured Be isotopes in a range of depositional environments from open marine, sub-ice shelf and subglacial settings throughout Prydz Bay, one of Antarctica's largest ice drainage systems. We find that strong s...
Article
Full-text available
We present centennial-scale radiocarbon (¹⁴C) records archived by deep sea stylasterid corals from the outer shelf and upper slope of the Antarctic margin. These novel stylasterids (Errina spp.) were collected from the western Ross Sea shelf (500 m) and slope (1,700 m), as well as the eastern Wilkes Land shelf (670 m). We provide two corals from ea...
Article
Full-text available
URL: http://rdcu.be/A1wP <- this is the link to a free read-only version of the paper. Abstract: Most seafloor communities at depths below the photosynthesis zone rely on food that sinks through the water column. However, the nature and strength of this pelagic–benthic coupling and its influence on the structure and diversity of seafloor communitie...
Article
Full-text available
The biodiversity, ecosystem services and climate variability of the Antarctic continent and the Southern Ocean are major components of the whole Earth system. Antarctic ecosystems are driven more strongly by the physical environment than many other marine and terrestrial ecosystems. As a consequence, to understand ecological functioning, cross-disc...
Research
Full-text available
A visualisation of the Bathymetry Digital Elevation Model (DEM) collected around the Windmill Islands, in East Antarctica. The visualisation shows the surface of the sea floor, and geological and sub-glacial features such as moraines, meltwater channels, glacial lineations, and fault lines. For further information see: http://www.sciencedirect.com/...
Article
A high-resolution multibeam sonar dataset covering an area of ca. 33 km² was collected in the vicinity of the Windmill Islands (67°S, 110°E), Wilkes Land, East Antarctica. The new data permit visualisation of the nearshore seafloor morphology in unprecedented detail, providing invaluable insight into the ice-sheet history of the region. A range of...
Article
This study presents the first analysis of benthic megafauna and habitats from the Sabrina Coast shelf, encompassing a proposed Marine Protected Area. Sea bed imagery indicated an abundant benthic fauna compared to other parts of the Antarctic shelf, dominated by brittle stars, polychaete tubeworms, and a range of other sessile and mobile taxa. The...
Conference Paper
Most seafloor communities below 200m water depth rely on food that sinks through the water-column. However, the nature and strength of coupling between surface and seafloor, termed benthic-pelagic coupling, and its influence on the structure and diversity of seafloor communities remains unclear, especially in Antarctica where ecological data are...
Article
The East Antarctic continental margin, which extends from the Weddell Sea to the Ross Sea (Fig. 1h), surrounds the largest and oldest ice mass on Earth; however, it has only been studied at a few locations because of its remoteness and persistent sea ice. The shelf is 100–150 km wide over most of its length but broadens where major crustal structur...
Article
Full-text available
Prydz Bay and the Mac.Robertson Land Shelf exhibit many of the variations seen on Antarctic continental shelves. The Mac.Robertson shelf is relatively narrow with rugged, inner-shelf topography and shallow outer-shelf banks swept by the westflowing Antarctic Coastal Current. U-shaped valleys cut across the shelf. It has thin sedimentary cover, depo...
Article
Full-text available
The East Antarctic Ice Sheet (EAIS) is the largest continental ice mass on Earth, and documenting its evolution since the Last Glacial Maximum (LGM) is important for understanding its present-day and future behaviour. As part of a community effort, we review geological evidence from East Antarctica that constrains the ice sheet history throughout t...
Article
Full-text available
Abstract A robust understanding of Antarctic Ice Sheet deglacial history since the Last Glacial Maximum is important in order to constrain ice sheet and glacial-isostatic adjustment models, and to explore the forcing mechanisms responsible for ice sheet retreat. Such understanding can be derived from a broad range of geological and glaciological da...
Article
Full-text available
A robust understanding of Antarctic Ice Sheet deglacial history since the Last Glacial Maximum is important in order to constrain ice sheet and glacial-isostatic adjustment models, and to explore the forcing mechanisms responsible for ice sheet retreat. Such understanding can be derived from a broad range of geological and glaciological datasets an...
Book
Full-text available
This new atlas, providing the most thorough audit of marine life in the Southern Ocean, is published by the Scientific Committee on Antarctic Research (SCAR). Leading marine biologists and oceanographers from all over the world spent the last four years compiling everything they know about the distribution of Antarctic marine species from microplan...
Chapter
Full-text available
The "Biogeographic Atlas of the Southern Ocean" is a legacy of the International Polar Year 2007-2009 (www.ipy.org) and of the Census of Marine Life 2000-2010 (www.coml.org), contributed by the Census of Antarctic Marine Life (www.caml.aq) and the SCAR Marine Biodiversity Information Network (www.scarmarbin.be; www.biodiversity.aq). The "Biogeograp...
Article
Full-text available
An international effort is underway to establish a representative system of marine protected areas (MPAs) in the Southern Ocean to help provide for the long-term conservation of marine biodiversity in the region. Important to this undertaking is knowledge of the distribution of benthic assemblages. Here, our aim is to identify the areas where benth...
Chapter
Regional classification analyses aim to identify biogeographic patterns, by spatially subdividing an area such that assemblage compositions can be expected to be similar within each region relative to adjacent regions. Here we outline a regional classification of the Southern Ocean benthos, intended for general use in spatial planning and managemen...
Chapter
The "Biogeographic Atlas of the Southern Ocean" is a legacy of the International Polar Year 2007-2009 (www.ipy.org) and of the Census of Marine Life 2000-2010 (www.coml.org), contributed by the Census of Antarctic Marine Life (www.caml.aq) and the SCAR Marine Biodiversity Information Network (www.scarmarbin.be; www.biodiversity.aq). The "Biogeograp...
Article
Full-text available
Sediment grainsize and compositional data is presented for the East Antarctic region (30-150ºE) south of 60ºS to provide insight into the nature of habitats available for benthic communities. This compilation of sedimentary properties incorporates data collected and analysed from the 1950s to 2012. Sediment grainsize data is presented from quantita...
Article
The surface sedimentary record from six cores collected from beneath the Amery Ice Shelf, East Antarctica, provides a unique view of the sedimentary and oceanographic processes in this sub-ice shelf setting. The composition and age of the surface sediments indicate spatial variations in ice shelf cavity-ocean interaction, which are consistent with...
Chapter
Full-text available
Prydz Bay and the Mac.Robertson Land shelf exhibit many of the variations seen on Antarctic continental shelves. The Mac.Robertson Shelf is relatively narrow with rugged, inner shelf topography and shallow outer shelf banks swept by the west-flowing Antarctic Coastal Current. U-shaped valleys cut across the shelf. It has thin sedimentary cover, dep...
Chapter
The George V margin is located in east Antarctica, in the region of the Mertz Glacier Tongue. The continental shelf break along this part of the margin occurs at an average depth of 500 m, extending to the abyssal plain below 3,500 m. Three main factors governing their distribution on this margin have been proposed: their depth in relation to icebe...
Conference Paper
Physical and biological characteristics of benthic communities on the George V Shelf have been analysed from underwater camera footage collecting during Aurora Australis voyages in 2007/08 and 2010/11. The 2007/08 data reveals a high degree of variability in the benthic communities across the shelf, with the benthic habitats strongly structured by...
Chapter
Full-text available
This book started as an idea at the GeoHab meeting held in Noumea, New Caledonia, in May 2007. We noticed that multibeam bathymetry maps of geomorphic features, sometimes shown as 3D fly-thru movies, followed by detailed sampling and photographic data (including underwater videos) illustrating the substrate conditions and associated biota was a con...
Chapter
Full-text available
Southeastern Bay of Biscay (Basque coast) seafloor characterization and benthic habitat mapping was carried out integrating data from multibeam echosounder, topographic and bathymetric LiDAR, video, and sediment and biological sampling ranging from the intertidal zone up to 100 m depth over 1,096 km 2. The area shows high geomorpho-logic diversity...
Article
Full-text available
The comatulid crinoid Anthometrina adriani is well represented among the suspension-feeding megaepibenthos from the continental shelf of the Dumont D’Urville Sea, Antarctica. Nearly 500 specimens were sampled during the Collaborative East Antarctic Marine Census expedition onboard the RV ‘Aurora Australis’ (December 2007 to January 2008), from 50 o...
Article
The RSV Aurora Australis survey allowed the first comprehensive study of the demersal ichthyofaunal environment and of the diversity of the Dumont d’Urville Sea. We observed a high dominance of the Notothenioidei in both the number of species and in integrated abundances. The Nototheniidae was the most abundant family with 44.7% of the total integr...
Article
Physical and biological characteristics of benthic communities are analysed from underwater video footage collected across the George V Shelf during the 2007/2008 CEAMARC voyage. Benthic habitats are strongly structured by physical processes operating over a range of temporal and spatial scales. Iceberg scouring recurs over timescales of years to c...
Article
Full-text available
The Collaborative East Antarctic Marine Census (CEAMARC) surveys to the Terre Adélie and George V continental margin highlight the requirement for a revised high-resolution bathymetry model that can be used as a spatial tool for improving information on the physical environment of the region. We have combined shiptrack singlebeam and multibeam bath...
Article
Ecoregions are defined in terms of community structure as a function of abiotic or even anthropogenic forcing. They are meso-scale structures defined as the potential habitat of a species or the predicted communities geographic extent. We assume that they can be more easily defined for long-lived species, such as benthos or neritic fish, in the mar...
Article
Full-text available
Dense coral-sponge communities on the upper continental slope at 570–950 m off George V Land, East Antarctica have been identified as Vulnerable Marine Ecosystems. The challenge is now to understand their probable distribution on other parts of the Antarctic margin. We propose three main factors governing their distribution on the George V margin:...
Article
Full-text available
Ecoregions are defined in terms of community structure as a function of abiotic or even anthropogenic forcing. They are meso-scale structures defined as the potential habitat of a species or the predicted communities geographic extent. We assume that they can be more easily defined for long-lived species, such as benthos or neritic fish, in the mar...
Article
The identification of marine habitats based on physical parameters is increasingly important for marine reserve design, allowing characterisation of habitat types over much wider areas than is possible from often patchy biological data. Marine management zones often contain a wide array of physical environments, which may not be captured in the bio...
Article
Full-text available
Two sediment cores collected from beneath the Amery Ice Shelf, East Antarctica describe the physical sedimentation patterns beneath an existing major embayed ice shelf. Core AM01b was collected from a site of basal freezing, contrasting with core AM02, collected from a site of basal melting. Both cores comprise Holocene siliceous muddy ooze (SMO),...
Article
Full-text available
This study presents compelling evidence for a diverse and abundant seabed community that developed over the course of the Holocene beneath the Amery Ice Shelf, East Antarctica. Fossil analysis of a 47 cm long sediment core revealed a rich modern fauna dominated by filter feeders (sponges and bryozoans). The down-core assemblage indicated a successi...
Article
Full-text available
To protect the diversity of marine life in Australia's Exclusive Economic Zone (EEZ), the Federal Parliament has passed the Environmental Protection and Biodiversity Conservation (EPBC) Act 1999. The Act is being implemented through the design of a national representative system of marine protected areas (MPAs) that will place under protection a re...
Article
Three areas in the Torres Strait - Gulf of Papua region were selected for detailed stud~ of sediments and benthic fossil biota. These areas form a transect across the shelf from the Fly River Delta to the shelf edge, near the northern extremity of the Great Barrier Reef. The Torres Strait - Gulf of Papua shelf is a shallow, low-gradient platform, w...
Article
Full-text available
The characterisation of benthic habitats based on their abiotic (physical and chemical) attributes remains poorly defined in the marine environment, but is becoming increasingly central in the development of marine management plans in Australia and elsewhere in the world. The current study tested this link between physical and biological datasets f...
Article
The oxygen isotopic record obtained from Globigerina bulloides, Globorotalia inflata, and Neogloboquadrina pachyderma (s.) was analysed for 5 sediment traps moored in the Southern Ocean and Southwest Pacific. The traps extend from Subtropical to the Polar Frontal environments, providing the first analysis of seasonal foraminiferal δ18O records from...