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1
Huyer, A., RL Smith, PJ Stabeno, JA Church, and NJ White. "Currents off south-eastern Australia: results from the Australian coastal experiment." Marine and Freshwater Research 39, no. 3 (1988): 245. http://dx.doi.org/10.1071/mf9880245.
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The Australian Coastal Experiment was conducted off the east coast of New South Wales between September 1983 and March 1984. The experiment was conducted with arrays of current meters spanning the continental margin at three latitudes (37.5�, 34.5�, and 33.0�S.), additional shelf moorings at 29� and 42�S. coastal wind and sea-level measurements, monthly conductivity-temperature-depth probe/expendable bathythermograph (CTD/XBT) surveys, and two satellite-tracked buoys. Over the continental shelf and slope, the alongshore component of the current generally exceeded the onshore component, and the subtidal (<0.6 cpd, cycles per day) current variability greatly exceeded the mean flow. Part of the current variability was associated with two separate warm-core eddies that approached the coast, causing strong (>50 cm sec-1), persistent (>8 days), southward currents over the continental slope and outer shelf. Temperature and geostrophic velocity sections through the eddies, maps of ship's drift vectors and temperature contours at 250 m, and the satellite-tracked drifter trajectories showed that these eddies were similar in structure to those observed previously in the East Australian Current region. Both eddies migrated generally southward. Eddy currents over the shelf and slope were rare at Cape Howe (37.5�S.), more common near Sydney (34.5�S.), and frequent at Newcastle (33.0�S.), where strong northward currents were also observed. Near Sydney, the eddy currents over the slope turned clockwise with depth between 280 and 740 m, suggesting net downwelling there. Repeated CTD sections also indicated onshore transport and downwelling at shallower levels; presumably, upwelling occurred farther south where the eddy currents turned offshore. Periodic rotary currents over the continental slope near Sydney and Newcastle indicated the presence of small cyclonic eddies on the flank of a much larger anticyclonic eddy. Between early October and late January, no strong southward currents were observed over the continental margin near Sydney. Data from this 'eddy-free' period were analysed further to examine the structure and variability of the coastal currents. Much of this variability was correlated with fluctuations in coastal sea-level (at zero lag) and with the wind stress (at various lags). The coherence and phase relationships among current, wind-stress, and sea-level records at different latitudes (determined from spectral analysis and frequency-domain empirical orthogonal functions) were consistent with the equatorward propagation of coastal-trapped waves generated by winds in phase with those near Cape Howe. Time-domain empirical orthogonal functions show that the current fluctuations decayed with distance from shore and with depth, as expected of coastal-trapped waves.
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Bax, Nicholas J., Michele Burford, Lesley Clementson, and Stevie Davenport. "Phytoplankton blooms and production sources on the south-east Australian continental shelf." Marine and Freshwater Research 52, no. 4 (2001): 451. http://dx.doi.org/10.1071/mf00001.
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During a large-scale ecosystem study on the south-east Australian shelf in spring 1994, we opportunistically sampled a widespread phytoplankton bloom. Thalassiosira partheneia, a small centric diatom, was the primary species in the bloom, indicating that we had sampled the early stage of a typical short-lived spring bloom for the area. Pigment analysis indicated four distinct communities that were coincident with the regional oceanography. The bloom was strongest over the northern shelf where the East Australian Current overlaid uplifted nutrient-rich slope water, but absent at inner stations on the wide southern shelf, where slope water did not reach. The bloom was patchy over the southern outer shelf where slope water was present to the surface and local conditions were influenced by topography. Pigment and stable isotope data indicated that primary production in this area was almost entirely oceanic. A slight trend for seaward enrichment of sediment δ13C is best explained by limited macroalgal growth in shallow waters. There was little fresh organic matter in the sediment even for stations under the bloom, suggesting that the bloom did not reach the seabed directly. The lack of specific zooplankton grazing pigments suggests that zooplankton grazing was minimal.
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Holloway, PE, and HC Nye. "Leeuwin current and wind distributions on the southern part of the Australian North West Shelf between January 1982 and July 1983." Marine and Freshwater Research 36, no. 2 (1985): 123. http://dx.doi.org/10.1071/mf9850123.
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Observations of the current and wind distributions on the southern part of the Australian North West Shelf between January 1982 and July 1983 are presented. Maps of monthly averages of winds and currents from a variety of locations are presented as well as some time series spanning 19 months of currents and water temperatures from a shelf-slope location and corresponding winds from a coastal station. The main feature of the observations is the strong flow to the south-west parallel to the bathymetry known as the Leeuwin Current. From the observations across the continental shelf, the low-frequency flow is strongest over the shelf break reaching a maximum speed of approximately 0 25 m s-1. The current is strongest between February and June. Reversals of the flow to the north- east are usually weak in strength and of short duration and are associated with strong south-west winds. However, observations of water temperature suggest the north-east currents cause weak upwelling events of cold deep water onto the shelf. The south-east trade winds blow from the south- east between March and August, but are shown to be inefficient in generating longshore currents to the south-west and hence in strengthening the Leeuwin Current.
4
Gibbs, Mark T., Patrick Marchesiello, and Jason H. Middleton. "Nutrient enrichment of Jervis Bay, Australia, during the massive 1992 coccolithophorid bloom." Marine and Freshwater Research 48, no. 6 (1997): 473. http://dx.doi.org/10.1071/mf97035.
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A numerical simulation of the East Australian Current (EAC) has been used to investigate the nutrification of shelf waters at Jervis Bay, south-eastern Australia, prior to the massive coccolithophorid bloom that was first observed on 16 December 1992. The simulation suggests that a small cold-core eddy developed between the continental slope at Jervis Bay and the EAC jet further offshore during 7 and 14 December 1992. This unstable cold-core eddy is likely to have uplifted cold, nutrient-rich water onto the Jervis Bay shelf, and this upwelling, in combination with upwelling-favourable winds, probably transported nutrients from the deep ocean to the entrance of the bay.
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MITCHELL, KIRSTY D., KATHRYN A. HALL, and JOHN N. A. HOOPER. "A new species of Sigmaxinella Dendy, 1897 (Demospongiae, Poecilosclerida, Desmacellidae) from the Tasman Sea." Zootaxa 2901, no. 1 (June 1, 2011): 19. http://dx.doi.org/10.11646/zootaxa.2901.1.2.
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Sigmaxinella hipposiderus sp. nov. is described from morphological and molecular datasets, based on a single known specimen collected from the upper margin of a submarine canyon on the edge of the continental shelf, south-east of coastal Victoria (Tasman Sea), Australia. Morphologically, the species is clearly assigned to the genus Sigmaxinella, and preliminary molecular data (COI mt DNA) support the close relationship of this new species to other specimens attributed to Desmacellidae. This is the thirteenth species of Sigmaxinella and the seventh described for the Australian EEZ. Remarkably, 12 of the 13 known species are recorded predominantly from temperate or subantarctic Australian, New Zealand or South African waters, with only a single species described so far from the temperate Atlantic Ocean.
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Prince, Jeremy D., and David A. Griffin. "Spawning dynamics of the eastern gemfish (Rexea solandri) in relation to regional oceanography in south-eastern Australia." Marine and Freshwater Research 52, no. 4 (2001): 611. http://dx.doi.org/10.1071/mf00007.
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Experienced fishers believe the winter aggregations of gemfish are influenced by the following: cold bottom currents from the south and east flowing up onto the shelf; the edge of warm-core eddies; and topographic features along the shelf break. These claims were tested through observations made at sea during industry surveys of the winter gemfish seasons 1996 –98, and the study of 250 m isotherm charts, sea surface temperature data, and historic catch data. The study generally confirmed the anecdotal information collected from the fishers. The first gemfish aggregations of the winter season often form on the southern edge of a warm-core eddy. Secondarily, aggregations tend to form around the northern edge of the warm-core eddy if it is interacting with the shelf break. Finally, gemfish aggregate around the point at which the main flow of the East Australian Current (EAC) detaches from the continental shelf. This timing and location apparently coincides with conditions conducive to the production of subsurface plumes of nutrient-rich deep Sub-Antarctic mode Water. These plumes lead to seasonal enhancement of phytoplankton growth along the edge of the continental shelf, which may offer the adaptive advantage of enhancing the survival and growth of larval gemfish.
7
Cresswell, G. "Nutrient enrichment of the Sydney continental shelf." Marine and Freshwater Research 45, no. 4 (1994): 677. http://dx.doi.org/10.1071/mf9940677.
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Nutrient-rich waters arrived at the continental shelf at Sydney in late January 1992 in two ways: as an intrusion from the nearby continental slope and as a cold upwelled plume originating several hundred kilometres farther north. With the former, an undercurrent flowed northward on the upper continental slope south of where the nearshore edge of a warm anticyclonic eddy separated from the shelf and curved out to sea. The undercurrent rose onto the floor of the shelf and spread shoreward at least to the 60-m isobath as an intrusion of slope water. The other source of nutrients, the upwelled plume from the north, probably resulted from the East Australian Current spreading onto the shelf and driving an Ekman bottom boundary layer shoreward, where it upwelled to the surface and was then advected southward. Very high values of fluorescence at 20-40 m depth in the plume suggested a significant phytoplankton bloom. The plume was not continuous at the surface for the final 100 km of its passage to Sydney, rather taking the form of 40-km-long 'slugs' moving at -0.3 m s-1. It was, however, continuous beneath the surface. From Sydney it was carried out to sea around the perimeter of the anticyclonic eddy.
8
Griffin, DA, JH Middleton, and L. Bode. "The tidal and longer-period circulation of Capricornia, Southern Great Barrier Reef." Marine and Freshwater Research 38, no. 4 (1987): 461. http://dx.doi.org/10.1071/mf9870461.
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Between June and December 1983, nine current meters and three water level recorders were deployed on the continental shelf and slope of the Capricornia Section of the Great Barrier Reef between Fraser Island (25�s.) and the mouth of the Capricorn Channel (23�s.) on the east coast of Australia. Tidal analyses of the hourly data set reveal an amplification of the semi-diurnal tides as they propagate north- westward into the Capricorn Channel. The results of a numerical model of tidal flow show excellent agreement with observations. The daily averaged (non-tidal) currents are highly variable and produce complex circulation patterns, but with a mean flow generally alongshore to the north-west. Comparisons with previous drifter studies and satellite-tracked buoy data suggest that the south-eastward flowing East Australian Current drives a large clockwise eddy, in the lee of the Swain Reefs, located east of the study region. It is postulated that this eddy, in addition to the generally north-westward wind stress, contributes to the north-westward flow within the study region. Temperatures recorded by the deployed instruments and temperature profiles from conductivity-temperature-depth casts confirm that tidal and longer period variablity contribute to upwelling onto the continental shelf.
9
Rattray, Alex, Daniel Ierodiaconou, Laurie Laurenson, Shoaib Burq, and Marcus Reston. "Hydro-acoustic remote sensing of benthic biological communities on the shallow South East Australian continental shelf." Estuarine, Coastal and Shelf Science 84, no. 2 (September 2009): 237–45. http://dx.doi.org/10.1016/j.ecss.2009.06.023.
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Hallegraeff, GM, and SW Jeffrey. "Annually recurrent diatom blooms in spring along the New South Wales coast of Australia." Marine and Freshwater Research 44, no. 2 (1993): 325. http://dx.doi.org/10.1071/mf9930325.
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Blooms of phytoplankton (100-280 mg chlorophyll a m-1) occur on the continental shelf off Sydney in the spring of most years. These sudden chlorophyll increases (more than 10 times the normal algal biomass) are due to short-lived diatom blooms that evolve in a predictable sequence from small chainforming species (Nitzschia, Thalassiosira) to large centric species (Lauderia, Rhizosolenia) and eventually to large dinoflagellates (Protoperidinium). Two research cruises (October 1981, September 1984) were conducted to define the longshore extent of this phenomenon. Diatom blooms were widespread along the whole New South Wales coastline, occurring in the 700-km-long region from Cape Hawke in the north (32°S), where the East Australian Current separates from the coast, to Maria Island off Tasmania in the south (43°S). Hydrological mechanisms of these annually recurrent enrichments are related to the action of the East Australian Current and are unlike those triggering spring blooms in temperate European waters. Implications of these diatom blooms for coastal fisheries along the New South Wales coast are briefly discussed.
11
Williams, Alan, and Nicholas J. Bax. "Delineating fish-habitat associations for spatially based management: an example from the south-eastern Australian continental shelf." Marine and Freshwater Research 52, no. 4 (2001): 513. http://dx.doi.org/10.1071/mf00017.
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A multi-scale, multi-gear survey identified the spatial structure and compositions of fish communities from a range of seabed types on the south-eastern Australian continental shelf (25 m to ~200 m depth). Most communities are species-rich and contain many shared species. Multivariate analysis of distributions of 201 fishes showed communities to be correlated with depth, latitude and seabed type;correlation with hydrodynamic climate is suggested by patterns in morphology. Depth-related patterns occurred on soft-sediment and hard substrata; strong latitudinal (south-west/north-east)patterns identify the area as a faunal transition zone with a major faunal disjunction extending across the shelf. Community patterns were overlaid on distributions of substrata to produce a biophysical map. This mapping process is discussed in the context of spatial management:the ecologically significant scale at which to map habitat features and definition of management units for ecosystem-based management. A hierarchy of scaled ecological units is being developed for Australia’s National Representative System of Marine Protected Areas (NRSMPA);given the scope of the NRSMPA initiative, surrogate measures of community structure will be required. Maps of substrata and topography, interpreted in the context of the broader depth and latitudinal community structure and as modified by hydrography, may provide one useful surrogate.
12
Schahinger, RB. "Structure of coastal upwelling events observed off the south-east coast of South Australia during February 1983 - April 1984." Marine and Freshwater Research 38, no. 4 (1987): 439. http://dx.doi.org/10.1071/mf9870439.
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Observations of upwelling along the south-east coast of South Australia during the summers of 1983 and 1984 are presented. In situ measurements were obtained from a number of current meters moored across the continental shelf near 37.5�S.,139.5�E. These were complemented by wind and sea level measurements along the coast and also monthly hydrographic surveys. Differences between summer and winter regimes are discussed in both physical and dynamical terms. The summer weather pattern gives rise to winds which are favourable to upwelling along this coast more than 50% of the time (i.e. winds from the south-east quarter). The evolution of two upwelling events and the associated shelf circulation are documented. Salient features include the offshore transport of water in a shallow surface layer 0 (20 m) in response to south-easterly winds; an onshore compensatory flow occurs almost immediately below. The summer thermocline shoals soon after the onset of winds favouring upwelling, leading to pronounced cross-shelf surface-temperature gradients with cooler (upwelled) water at the surface near the coast. The surfaced thermocline moves offshore and attains an equilibrium position in the vicinity of the shelf edge (after 4-5 days), as shown by infrared satellite images, while water from depths of 250-300 m encroaches onto the shelf. Alongshore currents reach speeds of more than 50 cm s-1 in the outer-shelf region and are strongly influenced by the position of the upwelling front. Brief comparisons are drawn with other upwelling regions.
13
Goswami, A., P. L. Olson, L. A. Hinnov, and A. Gnanadesikan. "OESbathy version 1.0: a method for reconstructing ocean bathymetry with generalized continental shelf-slope-rise structures." Geoscientific Model Development 8, no. 9 (September 3, 2015): 2735–48. http://dx.doi.org/10.5194/gmd-8-2735-2015.
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Abstract. We present a method for reconstructing global ocean bathymetry that combines a standard plate cooling model for the oceanic lithosphere based on the age of the oceanic crust, global oceanic sediment thicknesses, plus generalized shelf-slope-rise structures calibrated at modern active and passive continental margins. Our motivation is to develop a methodology for reconstructing ocean bathymetry in the geologic past that includes heterogeneous continental margins in addition to abyssal ocean floor. First, the plate cooling model is applied to maps of ocean crustal age to calculate depth to basement. To the depth to basement we add an isostatically adjusted, multicomponent sediment layer constrained by sediment thickness in the modern oceans and marginal seas. A three-parameter continental shelf-slope-rise structure completes the bathymetry reconstruction, extending from the ocean crust to the coastlines. Parameters of the shelf-slope-rise structures at active and passive margins are determined from modern ocean bathymetry at locations where a complete history of seafloor spreading is preserved. This includes the coastal regions of the North, South, and central Atlantic, the Southern Ocean between Australia and Antarctica, and the Pacific Ocean off the west coast of South America. The final products are global maps at 0.1° × 0.1° resolution of depth to basement, ocean bathymetry with an isostatically adjusted multicomponent sediment layer, and ocean bathymetry with reconstructed continental shelf-slope-rise structures. Our reconstructed bathymetry agrees with the measured ETOPO1 bathymetry at most passive margins, including the east coast of North America, north coast of the Arabian Sea, and northeast and southeast coasts of South America. There is disagreement at margins with anomalous continental shelf-slope-rise structures, such as around the Arctic Ocean, the Falkland Islands, and Indonesia.
14
Sloyan, Bernadette M., Ken R. Ridgway, and Rebecca Cowley. "The East Australian Current and Property Transport at 27°S from 2012 to 2013." Journal of Physical Oceanography 46, no. 3 (March 2016): 993–1008. http://dx.doi.org/10.1175/jpo-d-15-0052.1.
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AbstractThe East Australian Current (EAC) is the complex and highly energetic poleward western boundary current of the South Pacific Ocean. A full-depth current meter and property (temperature and salinity) mooring array was deployed from the continental shelf to the abyssal waters off Brisbane Australia (27°S) for 18 months from April 2012 to August 2013. The EAC mooring array is an essential component of the Australian Integrated Marine Observing System (IMOS). During this period the EAC was coherent with an eddy kinetic to mean kinetic energy ratio of less than 1. The 18-month, mean, poleward-only mass transport above 2000 m is 22.1 ± 7.5 Sverdrups (Sv; 1 Sv ≡ 106 m3 s−1). The mean, poleward-only heat transport and flow-weighted temperature above 2000 m are −1.35 ± 0.42 PW and 15.33°C, respectively. A difference in the poleward-only and net poleward mass and heat transports above 2000 m of 6.3 Sv and 0.24 PW reflects the presence of an equatorward EAC retroflection at the eastern (offshore) end of the mooring array. A complex empirical orthogonal function (EOF) analysis of the along-slope velocity anomalies finds that the first two modes explain 72.1% of the velocity variance. Mode 1 is dominant at periods of approximately 60 days, and mode 2 is dominant at periods of 120 days. These dominant periods agree with previous studies in the Tasman Sea south of 27°S and suggest that variability of the EAC in the Tasman Sea may be linked to variability north of 27°S.
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Moore, A. M. G., H. M. J. Stagg, and M. S. Norvick. "DEEP-WATER OTWAY BASIN: A NEW ASSESSMENT OF THE TECTONICS AND HYDROCARBON PROSPECTIVITY." APPEA Journal 40, no. 1 (2000): 66. http://dx.doi.org/10.1071/aj99005.
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The northwest-trending Otway Basin in southeast Australia formed during the separation of Australia and Antarctica between the latest Jurassic and the Early Cainozoic. A new, deep-seismic data set shows that the basin comprises two temporally and spatially overlapping rift components:the mainly Late Jurassic to mid-Cretaceous, east-west trending, inner Otway Basin—comprising the onshore basin and most of the continental shelf basin; andthe northwest–southeast to north–south trending depocentres beneath the outer shelf and continental slope, extending from eastern South Australia to the west coast of Tasmania, and a relatively minor and ill-defined sub-basin underlying the continental rise in water depths greater than about 4,500 m. This rift system was most active from the mid-Cretaceous to Palaeogene, and was strongly affected by sinistral strike-slip motion as Australia and Antarctica separated.The continental slope elements contain the bulk of the sediment volume in the basin. From northwest to southeast, these elements comprise the Beachport and Morum Sub-basins, the north-south trending Discovery Bay High, and the Nelson Sub-basin which appears to be structurally and stratigraphically continuous with the Sorell Basin off west Tasmania.The reflection character of the crust and upper mantle varies widely across the basin, and there is a strong correlation between that character and the basin configuration. It appears that accommodation space beneath the slope basin was created largely by extension and removal of most of the laminated deep continental crust.There is encouragement for hydrocarbon exploration in the deep-water basin. Firstly, there are indications of diagenesis related to fluid flow in and above the strongly faulted Cretaceous section in the Morum Sub-basin. As an Early Cretaceous petroleum system is already proven beneath the continental shelf, this suggests that the same system is also active in deep-water. Secondly, existing sample data suggest that a second, Late Cretaceous petroleum system could be active where any source rocks are sufficiently deeply buried; this condition would probably be met in the Nelson Sub-basin.
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Goswami, A., P. L. Olson, L. A. Hinnov, and A. Gnanadesikan. "OESbathy version 1.0: a method for reconstructing ocean bathymetry with realistic continental shelf-slope-rise structures." Geoscientific Model Development Discussions 8, no. 4 (April 2, 2015): 3079–115. http://dx.doi.org/10.5194/gmdd-8-3079-2015.
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Abstract. We present a method for reconstructing global ocean bathymetry that uses a plate cooling model for the oceanic lithosphere, the age distribution of the oceanic crust, global oceanic sediment thicknesses, plus shelf-slope-rise structures calibrated at modern active and passive continental margins. Our motivation is to reconstruct realistic ocean bathymetry based on parameterized relationships of present-day variables that can be applied to global oceans in the geologic past, and to isolate locations where anomalous processes such as mantle convection may affect bathymetry. Parameters of the plate cooling model are combined with ocean crustal age to calculate depth-to-basement. To the depth-to-basement we add an isostatically adjusted, multicomponent sediment layer, constrained by sediment thickness in the modern oceans and marginal seas. A continental shelf-slope-rise structure completes the bathymetry reconstruction, extending from the ocean crust to the coastlines. Shelf-slope-rise structures at active and passive margins are parameterized using modern ocean bathymetry at locations where a complete history of seafloor spreading is preserved. This includes the coastal regions of the North, South, and Central Atlantic Ocean, the Southern Ocean between Australia and Antarctica, and the Pacific Ocean off the west coast of South America. The final products are global maps at 0.1° × 0.1° resolution of depth-to-basement, ocean bathymetry with an isostatically adjusted, multicomponent sediment layer, and ocean bathymetry with reconstructed continental shelf-slope-rise structures. Our reconstructed bathymetry agrees with the measured ETOPO1 bathymetry at most passive margins, including the east coast of North America, north coast of the Arabian Sea, and northeast and southeast coasts of South America. There is disagreement at margins with anomalous continental shelf-slope-rise structures, such as around the Arctic Ocean, the Falkland Islands, and Indonesia.
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Holloway, PE, G. Symonds, and Vaz R. Nunes. "Observations of circulation and exchange processes in Jervis Bay, New South Wales." Marine and Freshwater Research 43, no. 6 (1992): 1487. http://dx.doi.org/10.1071/mf9921487.
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This paper discusses oceanographic observations obtained in and near Jervis Bay, a small coastal embayment of approximately 124 km2 situated on the New South Wales coast, during a series of measurement programmes spanning three years. Various mechanisms that drive water circulation within the bay and water exchange between the bay and the adjacent continental shelf are discussed. Current meter data from within the bay show surprisingly little correlation with the wind. Currents are characterized by persistent flows in one direction for periods of months, and it is suggested that influences from the shelf are responsible for driving the bay circulation. Flow through the bay entrance is weakly correlated with the wind at a period of around eight days, with near-surface inflow on the southern side of the entrance being in phase with deeper outflow on the northern side and vice versa. The shelf waters are well known for their coastally trapped waves. These have the potential to oscillate vertically the density surfaces on the shelf on a time scale of around eight days, and observations indicate that these waves are an additional mechanism driving circulation in the bay. The shelf waters are influenced by the warm East Australia Current and its eddies, and this appears to maintain a density contrast between the bay and the shelf for most of the year, with the shelf waters being less dense, which may be an additional mechanism driving bay circulation. Current-meter data from the bay entrance show a persistent northward current component in contrast to the strong southward flow of the East Australia Current on the shelf. Conductivity-temperature- depth data reveal cold, dense water flowing out of the bay during periods of strong winter cooling and the effects of warm eddies pushing warm water into the bay and displacing cold deeper water away from the bay. The heating/cooling cycle of the bay appears to be influenced by advection processes on the shelf as well as by aidsea heat and radiation exchanges.
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Middleton, JH, P. Coutis, DA Griffin, A. Macks, A. McTaggart, MA Merrifield, and GJ Nippard. "Circulation and water mass characteristics of the southern Great Barrier Reef." Marine and Freshwater Research 45, no. 1 (1994): 1. http://dx.doi.org/10.1071/mf9940001.
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Data acquired during a winter (May) cruise of the RV Franklin to the southern Great Barrier Reef indicate that the dynamics of the shelf/slope region are governed by the tides, the poleward-flowing East Australian Current (EAC), and the complex topography. Over the Marion Plateau in water deeper than - 100 m, the EAC appears to drive a slow clockwise circulation. Tides appear to be primarily responsible for shelf/slope currents in the upper layers, with evidence of nutrient uplift from the upper slope to the outer shelf proper in the Capricorn Channel. Elsewhere, the bottom Ekrnan flux of the strongly poleward-flowing EAC enhances the sloping isotherms associated with the longshore geostrophic balance, pumping nutrient-rich waters from depth to the upper continental slope. Generally, shelf waters are cooler than oceanic waters as a consequence of surface heat loss by radiation. A combination of heat loss and evaporation from waters flowing in the shallows of the Great Sandy Strait appears to result in denser 'winter mangrove waters' exporting low-oxygen, high-nutrient waters onto the shelf both north and south of Fraser Island; these subsequently mix with shelf waters and finally flow offshore at - 100 m depth, just above the salinity-maximum layer, causing anomalous nutrient values in the region of Fraser Island.
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McLoughlin, RJ, and PC Young. "Sedimentary provinces of the fishing grounds of the North West Shelf of Australia: Grain-size frequency analysis of surficial sediments." Marine and Freshwater Research 36, no. 5 (1985): 671. http://dx.doi.org/10.1071/mf9850671.
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As part of a multidisciplinary study of the continental shelf of north-west Australia, 354 sediment samples were taken to describe the distribution of sedimentary provinces contained within the region. A grain-size frequency analysis and subsequent classification have revealed six principal sediment types roughly corresponding to an east-west and inshore-offshore distribution. The study area is characterized by coarse skeletal detritus in the south-west, with a transition to a significant accretionary carbonate component in the form of oolites, pellets and infilled biogenic particles in the north-east. Superimposed on this pattern is a decrease in grain size from shallow to deeper waters, culminating in carbonate muds on the shelf slope. Carbonate content of sediments is uniformly high, ranging from 60 to 100% of the total weight of all samples. Non-carbonate material is principally clay; however, small quantities (less than 1%) of fine sand-size angular quartz are present.
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Kitchener, D. J., S. Hisheh, L. H. Schmitt, and A. Suyanto. "Shrews (Soricidae: Crocidura) from the Lesser Sunda Islands, and South-East Maluku, eastern Indonesia." Australian Mammalogy 17, no. 1 (1994): 7. http://dx.doi.org/10.1071/am94002.
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Crocidura maxi Sody, 1936 is extremely rare in collections and nothing is recorded of its general biology. It is recorded here for the frrst time from the islands of Bali, Alor, Timor, Roti, Kai Besar and Aru. The last mentioned is the first occasion that a shrew has been recorded from an island on the Australian continental shelf. Most parous females collected, in April, May and October, were pregnant, with an average of 2.0 (1-3) foetuses, or had recently given birth. In April, reproductive condition was not tightly synchronous among females. Crocidura maxi occurs in a wide range of habitats from grassland, mixed gardens (kebun), lowland riparian or gully rainforests at or near sea level, to lowland montane forests at 1300 m altitude. These shrews frequent grass nests of Alang Alang (lmperata cylindrica), either singly or as an adult male and female pair with their young, and occur in or beneath rotting logs or fallen canopy detritus. Crocidura maxi is sexually dimorphic on the islands of Alor and Flores, and differs morphologically between the islands. The sexes differ significantly in external and skull morphology. Genetic variability within island populations of C. maxi is well within the general mammalian range. Genetic distances are also typical of those observed for conspecific mammalian populations. An isolation by distance effect, in which genetic distance correlates positively with geographic separation, did not quite reach statistical significance. The genetic observations are consistent with population fragmentation and limited migration between C. maxi populations. Croci dura brunnea pudjonica Sody, 1936 is recorded for the first time from Bali Island. Basic morphometric and genetic data are presented.
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Oliver, Paul M., Mozes P. K. Blom, Harold G. Cogger, Robert N. Fisher, Jonathan Q. Richmond, and John C. Z. Woinarski. "Insular biogeographic origins and high phylogenetic distinctiveness for a recently depleted lizard fauna from Christmas Island, Australia." Biology Letters 14, no. 6 (June 2018): 20170696. http://dx.doi.org/10.1098/rsbl.2017.0696.
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Striking faunal turnover across Asia and Australasia, most famously along the eastern edge of the Sunda Shelf or ‘Wallace's Line’, has been a focus of biogeographic research for over 150 years. Here, we investigate the origins of a highly threatened endemic lizard fauna (four species) on Christmas Island. Despite occurring less 350 km south of the Sunda Shelf, this fauna mostly comprises species from clades centred on the more distant regions of Wallacea, the Pacific and Australia (more than 1000 km east). The three most divergent lineages show Miocene (approx. 23–5 Ma) divergences from sampled relatives; and have recently become extinct or extinct in the wild, likely owing to the recent introduction of a southeast Asian snake ( Lycodon capucinus ). Insular distributions, deep phylogenetic divergence and recent decline suggest that rather than dispersal ability or recent origins, environmental and biotic barriers have impeded these lineages from diversifying on the continental Sunda Shelf, and thereby, reinforced faunal differentiation across Wallace's Line. Our new phylogenetically informed perspective further highlights the rapid loss of ancient lineages that has occurred on Christmas Island, and underlines how the evolutionary divergence and vulnerability of many island-associated lineages may continue to be underestimated.
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Miskiewicz, AG, BD Bruce, and P. Dixon. "Distribution of Tailor (Pomatomus saltatrix) Larvae along the Coast of New South Wales, Australia." Marine and Freshwater Research 47, no. 2 (1996): 331. http://dx.doi.org/10.1071/mf9960331.
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The distribution of tailor (Pomatomus saltatrix) larvae is described on the basis of the results of four plankton surveys undertaken in northern and central New South Wales (NSW) coastal waters. These comprised a single survey during May 1989 along the northern NSW coast and multiple surveys in January, March and May 1983 between Sydney and Brisbane. Pomatomus saltatrix larvae occurred throughout the survey period, with the highest abundances on the northern NSW coast. Most larvae were caught in mid and outer continental shelf waters at water temperatures of ≥22�C. The only known spawning locality for P. saltatrix is in the vicinity of Fraser Island in southern Queensland from August to October. The occurrence of larvae along the NSW coast from January to May indicates that the spawning season of P. saltatrix is more extensive than previously reported and that spawning occurs along the east coast of Australia in localities other than Fraser Island. Further surveys of larvae in southern Queensland and northern NSW waters, especially from August to December, are required to determine if P. saltatrix has one extended or two discrete spawning seasons along the eastern coast of Australia.
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Taylor, Mark, Nick Fitzgerald, Jeremy Fitzpatrick, and Ralph Weiss. "The challenges of seismic acquisition in a remote and sensitive marine environment: Scott Reef, Western Australia." APPEA Journal 49, no. 2 (2009): 573. http://dx.doi.org/10.1071/aj08046.
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Woodside Energy Ltd, as operator of the Browse LNG Development, recently acquired two seismic surveys at Scott Reef, Western Australia. The surveys were important steps towards acquiring full seismic coverage over the Torosa gas field, part of which underlies Scott Reef The Maxima 3D marine seismic survey, conducted in late 2007, was a conventional towed streamer survey. This was followed in May 2008 by the Gigas 2D transition zone survey in the shallow waters of north Scott Reef, and Woodside’s first experience with ocean bottom cable (OBC) seismic technology. Each survey presented unique challenges during the planning, regulatory approval and acquisition stages. Scott Reef comprises two coral atolls located on the outer continental shelf of northwest Australia, approximately 400 km north of Broome. The only permanently emergent land is a small sand cay (Sandy Islet, Fig. 1), although the reef crests of both atolls are exposed at low tide. Outside the reefs the seafloor drops away rapidly, with water depths of about 350 m to the east, increasing to more than 1,000 m to the west. South Scott Reef lagoon is open to the north, with water depths increasing to about 50 m before deepening abruptly into the channel between the two reefs. North Scott Reef lagoon is shallower—generally less than 25 m—and is connected to the ocean by two narrow channels. Semi-diurnal tides with a range of up to 4.6 m produce strong tidal currents in and near these channels. Small, steep-sided coral heads, or bombies, are common throughout the lagoons, especially in water less than 25 m deep.
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Uruski, Chris. "Exploring New Zealand's marine territory." APPEA Journal 51, no. 1 (2011): 549. http://dx.doi.org/10.1071/aj10039.
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Around the end of the twentieth century, awareness grew that, in addition to the Taranaki Basin, other unexplored basins in New Zealand’s large exclusive economic zone (EEZ) and extended continental shelf (ECS) may contain petroleum. GNS Science initiated a program to assess the prospectivity of more than 1 million square kilometres of sedimentary basins in New Zealand’s marine territories. The first project in 2001 acquired, with TGS-NOPEC, a 6,200 km reconnaissance 2D seismic survey in deep-water Taranaki. This showed a large Late Cretaceous delta built out into a northwest-trending basin above a thick succession of older rocks. Many deltas around the world are petroleum provinces and the new data showed that the deep-water part of Taranaki Basin may also be prospective. Since the 2001 survey a further 9,000 km of infill 2D seismic data has been acquired and exploration continues. The New Zealand government recognised the potential of its frontier basins and, in 2005 Crown Minerals acquired a 2D survey in the East Coast Basin, North Island. This was followed by surveys in the Great South, Raukumara and Reinga basins. Petroleum Exploration Permits were awarded in most of these and licence rounds in the Northland/Reinga Basin closed recently. New data have since been acquired from the Pegasus, Great South and Canterbury basins. The New Zealand government, through Crown Minerals, funds all or part of a survey. GNS Science interprets the new data set and the data along with reports are packaged for free dissemination prior to a licensing round. The strategy has worked well, as indicated by the entry of ExxonMobil, OMV and Petrobras into New Zealand. Anadarko, another new entry, farmed into the previously licensed Canterbury and deep-water Taranaki basins. One of the main results of the surveys has been to show that geology and prospectivity of New Zealand’s frontier basins may be similar to eastern Australia, as older apparently unmetamophosed successions are preserved. By extrapolating from the results in the Taranaki Basin, ultimate prospectivity is likely to be a resource of some tens of billions of barrels of oil equivalent. New Zealand’s largely submerged continent may yield continent-sized resources.
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Bernecker, T., and D. H. Moore. "LINKING BASEMENT AND BASIN FILL: IMPLICATIONS FOR HYDROCARBON PROSPECTIVITY IN THE OTWAY BASIN REGION." APPEA Journal 43, no. 1 (2003): 39. http://dx.doi.org/10.1071/aj02002.
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Since the offshore discoveries of economic gas accumulations at Geographe and Thylacine, the Otway Basin has become the focus of an exploration resurgence. Its proximity to major markets ensures the discoveries will be commercially valuable. The latest successes in the basin are mainly due to modern 3D-seismic techniques. While the upper sedimentary succession has been imaged at high resolution, details of the deeper successions, however, remained obscure.An integrated study of magnetic, gravimetric, bathymetric and deep seismic data-sets has outlined the way that pre-existing basement fractures controlled much of the later basin-evolution, the structural style and the distribution of hydrocarbon bearing structures.The Otway Basin formed by the profound interaction between crustal fabric in the Proterozoic and Palaeozoic basement and the extensional stresses during Gondwana break-up. Overall, three different rift systems can be distinguished:Early ENE-trending Jurassic to Early Cretaceous rifts are an extension of the E-W rift system in Western Australia and South Australia, Early WNW Late Jurassic to Early Cretaceous rifts are connected to the ENE set and include the western Otway Basin east of the Robe Trough and the Torquay Sub-basin, and Early Cretaceous NNW transtensional rifts in the southern part of the Shipwreck Trough. These control the La Bella, Thylacine and Geographe discoveries, all of which overlie the Neoproterozoic to Cambrian Selwyn Block.Within these rift systems, the Jurassic to Cretaceous rifts along the continental shelf break coincide with the northern edge of the Voluta Trough, whilst the mid-slope rifts are part of the deep Voluta Trough and were possibly generated during the Late Cretaceous.Although the potential field data do not directly delineate hydrocarbon accumulations, when integrated with other data they provide powerful tools for exploration. For instance, it is possible to map the distribution of Paleocene channels that overlie the basement and represent likely reservoir facies, while data integration with palaeoenvironmental interpretations can highlight areas in which source rock facies developed.Regionally, the way the rifts have formed with respect to the basement fabric suggests that the dominant extension direction in the basin was N to NNW. Integrating the interpretation with regional studies in the western Tasmanian region supports the proposition that the western part of the south Tasman Rise was once the outer part of the upper plate adjacent to the deepwater parts of the Otway Basin SW of Cape Otway.
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Cresswell, G. R., J. L. Peterson, and L. F. Pender. "The East Australian Current, upwellings and downwellings off eastern-most Australia in summer." Marine and Freshwater Research 68, no. 7 (2017): 1208. http://dx.doi.org/10.1071/mf16051.
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The complex influences of the East Australian Current (EAC) and winds on the waters of the continental shelf were addressed with a ship survey, moored and drifting instruments, satellite images and wind and sea level measurements. The study revealed intrusions of continental slope water reaching the inner continental shelf when the EAC was near the shelf edge and wind stress was near zero or upwelling favourable (northerly). The process was the onshore movement of a southward flowing stream of water originally from the continental slope. One event was captured near Cape Byron and Evans Head when these waters upwelled to the surface. When the wind stress turned northward, it reversed the inner shelf current and drove downwelling. Variations in the wind stress also modulated the strength of the EAC out across the shelf to the upper slope. The strength of the EAC per se varied with a time scale of 2–3 months; these variations decreased in amplitude westward until they were undetectable at the inner shelf. The EAC had a subsurface speed maximum of up to 1.6ms–1 at 100–150-m depth above the continental slope and was seen to accelerate with both time and distance southward along the 190-km length surveyed by the ship.
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Freeland, Howard J. "Diurnal Coastal-Trapped Waves on the East Australian Continental Shelf." Journal of Physical Oceanography 18, no. 4 (April 1988): 690–94. http://dx.doi.org/10.1175/1520-0485(1988)018<0690:dctwot>2.0.co;2.
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Li, F., C. M. Griffiths, C. P. Dyt, P. Weill, M. Feng, T. Salles, and C. Jenkins. "Multigrain seabed sediment transport modelling for the south-west Australian Shelf." Marine and Freshwater Research 60, no. 7 (2009): 774. http://dx.doi.org/10.1071/mf08049.
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With increasing concerns about climate change and sea-level rise, there is a need for a comprehensive understanding of the sedimentary processes involved in the erosion, transport and deposition of sediment on the continental shelf. In the present paper, long-term and large-scale seabed morphological changes on the south-west Australian continental shelf were investigated by a comprehensive sediment transport model, Sedsim. The investigated area covers the continental shelf and abyssal basins of the south-western region. The regional seabed is sensitive to environmental forces and sediment supply, and most terrigenous sediment carried down by major rivers is trapped in inland lakes or estuaries. Only a small fraction of fine-grain sediment reaches the continental shelf. The simulation has also confirmed that the Leeuwin Current and high-energy waves play the most important roles in regional long-term seabed evolution. Although the numerical implementation only approximates some forcing and responses, it represents a significant step forward in understanding the nature of potential long-term seabed change as a response to possible climate change scenarios. The 50-year forecast on the seabed morphological changes provides a reference for the management of coastal and offshore resources, as well as infrastructure, in a sustainable way.
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Pearce, Alan, and Ming Feng. "Observations of warming on the Western Australian continental shelf." Marine and Freshwater Research 58, no. 10 (2007): 914. http://dx.doi.org/10.1071/mf07082.
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Global temperature datasets indicate a warming trend in the south-eastern Indian Ocean of ~0.02°C year–1. This is supported by in situ temperature measurements at a coastal monitoring station on the Western Australian continental shelf that have shown a mean temperature rise of 0.013°C year–1 since 1951, corresponding to ~0.6°C over the past 5 decades. Measurements from three other shallow stations between 1985 and 2004 indicated warming trends of 0.026–0.034°C year–1. It is suggested that enhanced air–sea heat flux into the south-eastern Indian Ocean may be a key factor in the rising temperature trend. There has also been a steady rise in salinity over the past half-century. At interannual scales, coherent temperature variability at the various stations indicates that larger-scale processes are influencing the shelf waters and are linked with El Niño/Southern Oscillation (ENSO)-related events in coastal sea level and hence the Leeuwin Current.
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Buchwald, VT, and BJ Kachoyan. "Shelf waves generated by a coastal flux." Marine and Freshwater Research 38, no. 4 (1987): 429. http://dx.doi.org/10.1071/mf9870429.
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Using the zero divergence approximation, we calculate the response of a continental shelf to an oscillating coastal current source which acts through a gap of finite width in the coastline. It is shown that this response consists of a forced oscillation in the neighbourhood of the gap, together with shelf waves appropriate to the shelf on either side. For a shelf of exponential slope similar to that of the East Australian shelf, and a flux through a channel of the dimensions of Bass Strait, the shelf wave response is shown to be qualitaticely similar to the results obtained in the Australian Coastal Experiment. This supports the contention that Bass Strait is a dominant source of shelf waves on the East Australian continental shelf. The 'eddy' mode required to explain the observations may also be attributed to the forced response of the shelf directly off-shore to Bass Strait. This paper also investigates the effect of adopting, in this physical context, simpler boundary conditions at the shelf edge. It is shown that there is some computational simplification, and that the results are largely unaffected by this simplification.
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Stankova, Svetla, Tzanko Tzankov, and Rosen Iliev. "The West Black Sea passive continental margin in the east part of Balkan Peninsula." Acta Scientifica Naturalis 5, no. 1 (March 1, 2018): 102–7. http://dx.doi.org/10.2478/asn-2018-0014.
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Abstract The Black Sea Neozoic passive continental margin marks the natural „bridge” between the Moesian and Bulgarian continental microplates and the Black Sea oceanic microplatte. It was coming in to being after the saturation between the terrains which are composed the Neo Europe south east part during the Early Paleogene. The subaerial part of the margin includes the most east parts of the South Moesian, Hemus, and Upper Thracian and Sakar-Strandzha morphostructural zones. The subaquatic part of the margin is composed by the consequently orderly step lower to the Black Sea bottom: high shelf zone, lover shelf zone, continental slope and continental foot. The Black Sea Neozoic passive continental margin is characterized by low seismic activity. It is concentrated in some fault zones.
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Church, John A., Neil J. White, Allan J. Clarke, Howard J. Freeland, and Robert L. Smith. "Coastal-Trapped Waves on the East Australian Continental Shelf Part II: Model Verification." Journal of Physical Oceanography 16, no. 11 (November 1986): 1945–57. http://dx.doi.org/10.1175/1520-0485(1986)016<1945:ctwote>2.0.co;2.
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Bax, Nicholas J., and Alan Williams. "Seabed habitat on the south-eastern Australian continental shelf: context, vulnerability and monitoring." Marine and Freshwater Research 52, no. 4 (2001): 491. http://dx.doi.org/10.1071/mf00003.
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A hierarchical approach to mapping seabed habitat is presented. A provincial scale survey that included hydrography and geology provided the context for interpreting habitat use and vulnerability. A megascale map, developed in cooperation with local fishers, identified major seabed features (kilometres to 10s of kilometres). Vulnerability of a feature was defined as its resistance to physical modification and its resilience, or capacity to recover, on removal of the modifier. Vulnerability was assessed from geological, biological and oceanological properties. Inner-shelf sandstone and limestone reefs that were exposed and weathered during the last ice age, and shelf-break bryozoan patch reefs, appear to be the most vulnerable of the hard-grounds to physical disturbance. In contrast, larger, high-relief, outer-shelf fossiliferous limestone reefs appear relatively invulnerable to physical disturbance from fishing. Megascale features were the focus of detailed physical and biological sampling at the mesoscale level (10 m to km), the level of resolution necessary for establishing baseline conditions and monitoring change. The hierarchical approach used here to map seabed habitat amalgamates scientific and fishers’ information. Approached in this way, habitat mapping has the potential to build a common framework of knowledge on which effective spatial management can be based.
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Falina, Anastasia, Artem Sarafanov, Herlé Mercier, Pascale Lherminier, Alexey Sokov, and Nathalie Daniault. "On the Cascading of Dense Shelf Waters in the Irminger Sea." Journal of Physical Oceanography 42, no. 12 (December 1, 2012): 2254–67. http://dx.doi.org/10.1175/jpo-d-12-012.1.
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Abstract Hydrographic data collected in the Irminger Sea in the 1990s–2000s indicate that dense shelf waters carried by the East Greenland Current south of the Denmark Strait intermittently descend (cascade) down the continental slope and merge with the deep waters originating from the Nordic Seas overflows. Repeat measurements on the East Greenland shelf at ~200 km south of the Denmark Strait (65°–66°N) reveal that East Greenland shelf waters in the Irminger Sea are occasionally as dense (σ0 > 27.80) as the overflow-derived deep waters carried by the Deep Western Boundary Current (DWBC). Clear hydrographic traces of upstream cascading of dense shelf waters are found over the continental slope at 64.3°N, where the densest plumes (σ0 > 27.80) originating from the shelf are identified as distinct low-salinity anomalies in the DWBC. Downstream observations suggest that dense fresh waters descending from the shelf in the northern Irminger Sea can be distinguished in the DWBC up to the latitude of Cape Farewell (~60°N) and that these waters make a significant contribution to the DWBC transport.
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Bai, Ying, Hong Liang Wang, Qian Ru Li, and Peng Wu. "Cenozoic Tectonic Evolution and Controlling Factor on Hydrocarbon Accumulation in the Southern East China Sea Shelf Basin." Applied Mechanics and Materials 416-417 (September 2013): 1908–13. http://dx.doi.org/10.4028/www.scientific.net/amm.416-417.1908.
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The East China Sea shelf basin, which is a fault subsidence during the Cenozoic Era, locates in the East China Sea continental shelf. In this paper, balanced section technique has been applied to analyzing the differential evolution in the East China Sea shelf basin south of Cenozoic tectonic and summarizing the control factors of tectonic activities on the petroleum accumulation. Our study results will provide essential data and basis for the distribution of the Cenozoic oil and gas and promote the development of the petroleum exploration in the East China Sea shelf basin.
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Beckley, LE, and AD Connell. "Early Life History of Pomatomus saltatrix off the East Coast of South Africa." Marine and Freshwater Research 47, no. 2 (1996): 319. http://dx.doi.org/10.1071/mf9960319.
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Several authors have stated that southward transport of the early life-history stages of Pomatomus saltatrix occurs by passive drift in the Agulhas Current, a strong western boundary current which flows southwards following the edge of the continental shelf of eastern South Africa. However, an extensive study of the ichthyoplankton occurring in shelf and Agulhas Current waters from 29�S to 34�S located P. saltatrix larvae only in the shelf waters off KwaZulu-Natal. Sampling of fish eggs in the inshore shelf waters 60 km south of Durban on a regular basis has confirmed spawning of P. saltatrix to occur in this region. The data thus suggest that larval dispersal might occur in shelf waters where, although strongly influenced by the Agulhas Current, southward transport is not as rapid.
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Church, John A., Howard J. Freeland, and Robert L. Smith. "Coastal-Trapped Waves on the East Australian Continental Shelf Part I: Propagation of Modes." Journal of Physical Oceanography 16, no. 11 (November 1986): 1929–43. http://dx.doi.org/10.1175/1520-0485(1986)016<1929:ctwote>2.0.co;2.
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PAIVA, M. P., C. A. S. ROCHA, A. M. G. GOMES, and M. F. ANDRADE. "Fishing grounds of bottom-liners on the continental shelf of south-east Brazil." Fisheries Management and Ecology 3, no. 1 (March 1996): 25–33. http://dx.doi.org/10.1111/j.1365-2400.1996.tb00127.x.
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Mollison, Kendall C., Hannah E. Power, Samantha L. Clarke, Alan T. Baxter, Emily M. Lane, and Thomas C. T. Hubble. "The sedimentology and tsunamigenic potential of the Byron submarine landslide off New South Wales, Australia." Geological Society, London, Special Publications 500, no. 1 (2020): 27–40. http://dx.doi.org/10.1144/sp500-2019-160.
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AbstractExtensive evidence for submarine landslide failure is found along the east Australian continental margin. This paper assesses the sedimentological properties and models the failure event that created the Byron landslide scar, located on the SE Australian continental margin, c. 34 km off the coast of Byron Bay, New South Wales. Sedimentological analyses and dating (radiocarbon and biostratigraphic) were conducted on three gravity cores collected from within the Byron landslide scar. A paraconformity, identified in one of the three cores by a distinct colour change, was found to represent a distinct radiocarbon age gap of at least 25 ka and probably represents the detachment surface of the slide plane. The core-derived sediment properties for the Byron landslide scar were used to inform hydrodynamic modelling using the freely available numerical modelling software, Basilisk. Model results highlight the important role of sediment rheology on the tsunamigenic potential of the slide and on the resulting inundation along the east Australian coastline, therefore providing a greater understanding of the modern hazard posed by comparable future submarine landslide events for the east Australian coastline.
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Kruse, Peter D. "Further Australian Cambrian sphinctozoans." Geological Magazine 124, no. 6 (November 1987): 543–53. http://dx.doi.org/10.1017/s0016756800017374.
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AbstractTwo new genera and species of Middle Cambrian sphinctozoans, Jawonya gurumal and Wagima galbanyin, are described from the Tindall Limestone of the Daly Basin, Northern Territory, within continental platform successions of the northern Australian craton. They are ambisiphonate sebargasiids, coeval with the island-arc shelf fauna from the Ordian Stage of western New South Wales. Additionally, a new Early Cambrian (Atdabanian equivalent) species, ?Jawonya tiro, displaying some sphinctozoan and some archaeocyathan features, is documented from the Ajax Limestone of the Arrowie Basin, South Australia. It is tentatively regarded as the oldest known sphinctozoan, but raises the possibility of the derivation of sphinctozoans from archaeocyaths. A brief review charts the Early–Middle Palaeozoic history of the sphinctozoans. The use of filling tissue type as a family-level criterion in sphinctozoan classification needs some reappraisal, as some types are of secondary origin.
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Paterson, James S., Sasi Nayar, James G. Mitchell, and Laurent Seuront. "A local upwelling controls viral and microbial community structure in South Australian continental shelf waters." Estuarine, Coastal and Shelf Science 96 (January 2012): 197–208. http://dx.doi.org/10.1016/j.ecss.2011.11.009.
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Pickart, Robert S., Daniel J. Torres, and Paula S. Fratantoni. "The East Greenland Spill Jet*." Journal of Physical Oceanography 35, no. 6 (June 1, 2005): 1037–53. http://dx.doi.org/10.1175/jpo2734.1.
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Abstract High-resolution hydrographic and velocity measurements across the East Greenland shelf break south of Denmark Strait have revealed an intense, narrow current banked against the upper continental slope. This is believed to be the result of dense water cascading over the shelf edge and entraining ambient water. The current has been named the East Greenland Spill Jet. It resides beneath the East Greenland/Irminger Current and transports roughly 2 Sverdrups of water equatorward. Strong vertical mixing occurs during the spilling, although the entrainment farther downstream is minimal. A vorticity analysis reveals that the increase in cyclonic relative vorticity within the jet is partly balanced by tilting vorticity, resulting in a sharp front in potential vorticity reminiscent of the Gulf Stream. The other components of the Irminger Sea boundary current system are described, including a presentation of absolute transports.
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Khan, Ajmal, Seerangan Manokaran, and Somasundharanair Lyla. "Changes in macrobenthic community structure from estuary to continental slope in the south-east coast of India." Journal of the Marine Biological Association of the United Kingdom 97, no. 1 (March 4, 2016): 161–80. http://dx.doi.org/10.1017/s0025315416000229.
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The pattern of changes in the macrobenthic community was studied along the south-east coast of India from the estuary to continental slope. A transect perpendicular to the coast was selected for sampling in estuary, inshore region, continental shelf and continental slope. Sampling was done in 16 stations in the depth range of 1.7–1000 m. The community structure was characterized in terms of species composition, abundance, diversity and feeding type. Four taxa were encountered in the study area comprising 181 species of polychaetes, 65 species of molluscs, 47 species of crustaceans and six species of ‘others’ (four echinoderms and two cnidarians). Polychaetes were found to be dominant at all the depths constituting 53.89% of the total abundance and 60.54% of the total number of species. Number of species and Shannon diversity of macrobenthos increased from estuary to shelf region and then decreased. The abundance was found to be maximum in the estuary and minimum in the slope. Carnivorous species were found to be dominant in the estuarine and inshore regions and surface deposit feeders in the shelf and slope regions. Dissolved oxygen decreased gradually from 30 m depth and beyond 150 m the decrease was pronounced due to the presence of the oxygen minimum zone. The distance based linear model (DISTLM) showed the environmental variables to explain about 76.45% of the total variability in macrofaunal distribution. Among the various environmental parameters, total organic carbon, depth and salinity explained more variability than others. Gradual change in community structure was quite evident with increase in depth.
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Distefano, Salvatore, Fabiano Gamberi, Niccolò Baldassini, and Agata Di Stefano. "Quaternary Evolution of Coastal Plain in Response to Sea-Level Changes: Example from South-East Sicily (Southern Italy)." Water 13, no. 11 (May 28, 2021): 1524. http://dx.doi.org/10.3390/w13111524.
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During a cycle of sea-level variation, coastal environments develop in different position of the continental shelf following seaward and landward shift of the coastline. They vary widely in character, reflecting the wide range of process-regimes that are brought about during the different stages of sea-level variations. Within this scenario, the morphology of continental shelves, mainly resulting from the combined effect of tectonic activity and eustatism, plays an important role in controlling the features and the preservation of coastal environments. Coastal deposits formed along continental shelves in the past, during different stages of sea-level changes, consist of discontinuous and thin depositional bodies, thus their reconstruction can be best carried out through the interpretation of high-resolution seismic data. Such a research approach is adopted in the present study to investigate a portion of the continental shelf of the southernmost sector of SE Sicily, in the offshore of Marzamemi village (Syracuse). The interpretation of high-resolution “Sparker” profiles allowed us to reconstruct the evolution of alluvial and lagoonal environments, established on a substratum of Pliocene or more ancient marine deposits, with the detection of several seismic units and unconformity surfaces, which have been related to alternating sedimentation and erosional processes, depicting the sea-level change framework of glacial-interglacial phases, from the late Pleistocene onward.
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Whitehead, J. M., P. G. Quilty, B. C. Mckelvey, and P. E. O’Brien. "A review of the Cenozoic stratigraphy and glacial history of the Lambert Graben—Prydz Bay region, East Antarctica." Antarctic Science 18, no. 1 (March 2006): 83–99. http://dx.doi.org/10.1017/s0954102006000083.
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The Cenozoic glacial history of East Antarctica is recorded in part by the stratigraphy of the Prydz Bay—Lambert Graben region. The glacigene strata and associated erosion surfaces record at least 10 intervals of glacial advance (with accompanying erosion and sediment compaction), and more than 17 intervals of glacial retreat (enabling open marine deposition in Prydz Bay and the Lambert Graben). The number of glacial advances and retreats is considerably less than would be expected from Milankovitch frequencies due to the incomplete stratigraphic record. Large advances of the Lambert Glacier caused progradation of the continental shelf edge. At times of extreme glacial retreat, marine conditions reached > 450 km inland from the modern ice shelf edge. This review presents a partial reconstruction of Cenozoic glacial extent within Prydz Bay and the Lambert Graben that can be compared to eustatic sea-level records from the southern Australian continental margin.
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Forbes, AMG. "Wind stress in the Australian coastal experiment region." Marine and Freshwater Research 38, no. 4 (1987): 475. http://dx.doi.org/10.1071/mf9870475.
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During the 6 months of the Australian Coastal Experiment (ACE), recordings were made by the Australian Bureau of Meteorology of several meteorological parameters at a number of coastal stations and by the CSIRO at several offshore locations to complement the ACE current-meter and sea-level gauge array. The aim was to examine the wind field over the New South Wales coast and so determine the magnitude of long shelf wind stress, which might locally force coastal trapped waves (CTW). Wind stress decreased equatorward, with the greatest potential for local CTW forcing lying on the southernmost continental shelf near Gabo Island. No significant variation in the magnitude of wind stress across the shelf within 20 km of the coast was observed. Despite the low sampling frequency at most coastai stations (twice daily, a subset of well-exposed coastal stations was sufficient to characterize the wind field over the entire region. The study revealed equatorward phase propagation of 9.2 and 12.1 m s-1 at periods of 4.4 and 10.5 days respectively.
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Pollock, R. M., Q. Li, B. McGowran, and S. C. Lang. "OLIGO-MIOCENE CANYONS IN THE GAMBIER SUB-BASIN, SOUTHERN AUSTRALIA—DEEPWATER ANALOGUES FOR PETROLEUM EXPLORATION." APPEA Journal 42, no. 1 (2002): 311. http://dx.doi.org/10.1071/aj01017.
Full textAbstract:
The Gambier Sub-basin lies on the southern Australian passive continental margin that formed during continental breakup and seafloor spreading between the Australian and Antarctic plates. In addition to the numerous modern submarine canyons reported on the southern Australian margin, three palaeo-canyon systems have been identified within the Gambier Limestone of the South Australian Gambier Sub-basin. Favourable environmental conditions during the Oligocene and Early Miocene led to deposition of the Gambier Limestone, a widespread, prograding extra-tropical carbonate platform. A world-wide glacio-eustatic sea level fall in the Early Oligocene exposed the shelf in the Gambier Subbasin, causing widespread erosion and minor fluvial incision on the shelf and subsequent formation of nick points at the shelf edge. During the following marine transgression later in the Oligocene, the shelf was inundated and the nick points provided conduits for erosive turbidity currents to enlarge the canyons to the spectacular dimensions observed on seismic data. No less than 20 successive canyon cut and fill events ranging from Late Oligocene to Middle Miocene have been observed and mapped on seismic data across the shelf in the Gambier Sub-basin. The thick, dominantly fine-grained carbonate sheet logically represents a potential regional seal to underlying clastic reservoirs. However, the possibility exists for carbonate reservoir sands to be present within the palaeo-canyons, sealed by surrounding fine-grained carbonates. Although no hydrocarbons have yet been identified in the carbonates of the Gambier Sub-basin, the canyons provide an analogue useful for establishing the scale, internal architecture and geometry of canyon fill systems.
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Little, John, Daniel J. Schmidt, Benjamin D. Cook, Timothy J. Page, and Jane M. Hughes. "Diversity and phylogeny of south-east Queensland Bathynellacea." Australian Journal of Zoology 64, no. 1 (2016): 36. http://dx.doi.org/10.1071/zo16005.
Full textAbstract:
The crustacean order Bathynellacea is amongst the most diverse and widespread groups of subterranean aquatic fauna (stygofauna) in Australia. Interest in the diversity and biogeography of Australian Bathynellacea has grown markedly in recent years. However, relatively little information relating to this group has emerged from Queensland. The aim of this study was to investigate bathynellacean diversity and phylogeny in south-east Queensland. Relationships between the south-east Queensland fauna and their continental relatives were evaluated through the analysis of combined mitochondrial and nuclear DNA sequence data. Bathynellaceans were collected from alluvial groundwater systems in three catchments in south-east Queensland. This study revealed a diverse bathynellacean fauna with complex evolutionary relationships to related fauna elsewhere in Queensland, and on the wider Australian continent. The multifamily assemblage revealed here is likely to represent several new species, and at least one new genus within the Parabathynellidae. These taxa likely have relatively restricted geographic distributions. Interestingly, the south-east Queensland Bathynellacea appeared to be distantly related to their north-east Queensland counterparts. Although it was not possible to determine the generic identities of their closest relatives, the south-east Queensland Parabathynellidae appear to be most closely affiliated with southern and eastern Australian lineages. Together with previous survey data, the findings here suggest that there is likely to be considerable bathynellacean diversity in alluvial groundwater systems across the wider Queensland region. Further assessment of stygofauna distributions in south-east Queensland is necessary to understand the biological implications of significant groundwater use and development in the region.
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Savina, Marie, Robyn E. Forrest, Elizabeth A. Fulton, and Scott A. Condie. "Ecological effects of trawling fisheries on the eastern Australian continental shelf: a modelling study." Marine and Freshwater Research 64, no. 11 (2013): 1068. http://dx.doi.org/10.1071/mf12361.
Full textAbstract:
The New South Wales Offshore Trawl Fishery began to expand in 1976, following a large exploratory trawl survey carried out on the fishing grounds of the upper continental slope. This survey was repeated 20 years later with the same vessel and using similar protocols. Comparison of the survey results suggested that the overall fish biomass in the survey area had substantially decreased after 20 years. We have implemented an ecosystem model using the Atlantis framework to (1) emulate the evolution of the shelf ecosystems from 1976 to 1996 and (2) explore the effects of alternative fishing pressures on those ecosystems. We have been able to emulate the observed decline of most of the commercial groups of fish species in the Offshore Trawl Fishery, including sharks, and our results confirmed that fishing pressure was the most important cause of these observed changes. Fourteen fishing scenarios highlight the competing nature of some of the ecosystem-based sustainable fishing objectives.
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Church, JA. "East Australian current adjacent to the Great Barrier Reef." Marine and Freshwater Research 38, no. 6 (1987): 671. http://dx.doi.org/10.1071/mf9870671.
Full textAbstract:
Hydrographic data from a series of cruises during 1980-1981 are used to determine the circulation in the western Coral Sea region immediately adjacent to the Great Barrier Reef. The data show flow westward towards the Great Barrier Reef, bifurcating just north of 18�S. During the monsoon season (December to February), the bifurcation point moves north to at least 14�s. The geostrophic westward flow has a subsurface maximum at a depth of about 150 m. South of the bifurcation point, the flow is south-eastward on the upper continental slope and north-eastward offshore. North of the bifurcation point, the surface flow and transport (relative to 900 dbar) are northward. However, there is sometimes a south-eastwards near-surface shear. Near the bifurcation point, the surface currents are weak and variable. All of these features of the surface flow are reflected in the paths followed by satellite-tracked drifters. Although the drifters were fixed infrequently, the drifter data indicate the possible presence of small cyclonic eddies in the region of the bifurcation. All of the satellite-tracked drifters went aground in the Great Barrier Reef within 30 days of entering the region offshore from the Reef. The data are consistent with recent models of the wind-driven circulation in the South Pacific that propose that the westward flow bifurcates at about 20�S., with 17 x 106 m3 s-1 flowing through the Indonesian Archipelago from the Pacific Ocean to the Indian Ocean.