Articoli di riviste: "Sea level South Australia St"

1

Cann, John H., Antonio P. Belperio, Victor A. Gostin e Colin V. Murray-Wallace. "Sea-Level History, 45,000 to 30,000 yr B.P., Inferred from Benthic Foraminifera, Gulf St. Vincent, South Australia". Quaternary Research 29, n. 2 (marzo 1988): 153–75. http://dx.doi.org/10.1016/0033-5894(88)90058-0.

Testo completo

Abstract (sommario):

Surficial sediments of Gulf St. Vincent, South Australia, are predominantly bioclastic, cool-temperate carbonates. Benthic foraminifera are abundant and distribution of species is closely related to water depth. For example, Massilina milletti is most common at depths ca. 40 m, while Discorbis dimidiatus is characteristics of shallow, subtidal environments. Elphidium crispum, a shallow-water species, and E. macelliforme, favoring deeper water, provide a useful numerical ratio. Their logarithmic relative abundance, in the sediment size fraction 0.50–0.25 mm, correlates strongly with water depth. Vibrocores SV 4 and SV 5 recovered undisturbed sections of Quaternary strata from the deepest part (ca. 40 m) of Gulf St. Vincent. Amino acid racemization and radiocarbon age determinations show that late Pleistocene sections of the cores were deposited over the time ca. 45,000 to 30,000 yr B.P. Species of fossil foraminifera, recovered from these sections, are mostly extant in modern Gulf St. Vincent, thus allowing paleoecological inferences of late Pleistocene sea levels. These inferred sea-level maxima can be correlated with those determined from study of Huon Peninsula coral reef terraces. Initial estimates of tectonically corrected sea levels for transgressions in Gulf St. Vincent at 40,000 and 31,000 yr B.P. are −22.5 m and −22 m, respectively. The intervening regression lowered sea level to −28 m.

Gli stili APA, Harvard, Vancouver, ISO e altri

2

Cann, J. H., A. P. Belperio, V. A. Gostin e R. L. Rice. "Contemporary benthic foraminifera in Gulf St Vincent, South Australia, and a refined Late Pleistocene sea‐level history". Australian Journal of Earth Sciences 40, n. 2 (aprile 1993): 197–211. http://dx.doi.org/10.1080/08120099308728074.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

3

Filby, Nicole E., Mike Bossley e Karen A. Stockin. "Behaviour of free-ranging short-beaked common dolphins (Delphinus delphis) in Gulf St Vincent, South Australia". Australian Journal of Zoology 61, n. 4 (2013): 291. http://dx.doi.org/10.1071/zo12033.

Testo completo

Abstract (sommario):

Common dolphins are subject to large-scale fishing activity and tourism operations in South Australia; however, there is a paucity of data on this species. Understanding the behaviour of a population can contribute greatly to our knowledge of a species and how to manage potential population-level threats. This paper describes the behaviour of short-beaked common dolphins (Delphinus delphis) in Australian waters for the first time. Data were collected from 109 independent dolphin groups during boat-based surveys conducted in Gulf St Vincent, South Australia, between September 2005 and May 2008. Activity budgets were used to assess behaviour of common dolphins in relation to diel patterns, season, water depth, sea surface temperature (SST), group size and composition. Foraging (33.9%) and resting (2.8%) were the most and least frequently observed behaviours, respectively. Travelling (33.0%), socialising (20.2%) and milling (10.1%) accounted for the remainder of the activity budget. Diurnal differences were detected, with foraging (59.5%) and socialising (31.8%) groups most frequently observed from 10.00 to 11.59 hours. Behaviour did not vary seasonally or with water depth, SST, group size or composition. Behaviour varied significantly between single- and multispecies aggregations. Foraging was more frequent in multispecies aggregations, as 78.4% of all foraging behaviour observed for common dolphins occurred in the presence of other species. Multispecies aggregations were most frequently observed with flesh-footed shearwaters (Puffinus carneipes), which were present during 29.4% of common dolphin encounters. Behaviour varied significantly during aggregations with shearwaters, as 62.2% of foraging groups occurred in the presence of shearwaters. Resting, milling or socialising was rarely observed in the presence of any other species, indicating that the primary mechanism for aggregations is likely prey-related.

Gli stili APA, Harvard, Vancouver, ISO e altri

4

Evans, Jenni L., e Aviva Braun. "A Climatology of Subtropical Cyclones in the South Atlantic". Journal of Climate 25, n. 21 (novembre 2012): 7328–40. http://dx.doi.org/10.1175/jcli-d-11-00212.1.

Testo completo

Abstract (sommario):

A 50-yr climatology (1957–2007) of subtropical cyclones (STs) in the South Atlantic is developed and analyzed. A subtropical cyclone is a hybrid structure (upper-level cold core and lower-level warm core) with associated surface gale-force winds. The tendency for warm season development of North Atlantic STs has resulted in these systems being confused as tropical cyclones (TCs). In fact, North Atlantic STs are a regular source of the incipient vortices leading to North Atlantic TC genesis. In 2004, Hurricane Catarina developed in the South Atlantic and made landfall in Brazil. A TC system had been previously unobserved in the South Atlantic, so the incidence of Catarina highlighted the lack of an ST climatology for the region to provide a context for the likelihood of future systems. Sixty-three South Atlantic STs are documented over the 50-yr period analyzed in this climatology. In contrast to the North Atlantic, South Atlantic STs occur relatively uniformly throughout the year; however, their preferred location of genesis and mechanisms for this genesis do exhibit some seasonal variability. Rossby wave breaking was identified as the mechanism for the ST vortex initiation for North Atlantic STs. A subset of South Atlantic STs forms via this mechanism, however, an additional mechanism for ST genesis is identified here: lee cyclogenesis downstream of the Andes in the Brazil Current region—an area favorable for convection. This formation mechanism is similar to development of type-2 east coast lows in the Tasman Sea off eastern Australia.

Gli stili APA, Harvard, Vancouver, ISO e altri

5

Edwards, Merinda, e Lou Wilson. "Planning for Sea Level Rise in South Australia". International Journal of Climate Change: Impacts and Responses 2, n. 1 (2010): 233–46. http://dx.doi.org/10.18848/1835-7156/cgp/v02i01/37303.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

6

Short, A. D. "The South Australia Coast and Holocene Sea-Level Transgression". Geographical Review 78, n. 2 (aprile 1988): 119. http://dx.doi.org/10.2307/214171.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

7

Ollier, Cliff. "Sea level and the carbonate sand factory of South Australia". Energy & Environment 28, n. 3 (12 dicembre 2016): 283–87. http://dx.doi.org/10.1177/0958305x16683079.

Testo completo

Abstract (sommario):

Stable parts of the South Australia coast show that the last interglacial sea level was 2 m higher than present, but elsewhere there has been relative subsidence up to 7 m and uplift of 18 m. Estimates of changing sea level, and future projections, should state the time period involved and the tectonic background to be of any use. The coast contains ‘carbonate sand factories’ where organisms produce vast amounts of sand by fixing carbon dioxide as carbonates. Far from dissolving carbonate by acidification, carbon dioxide is an essential part of carbonate production and the continued maintenance and growth of coasts and reefs. Government policies to adapt renewable energy are unlikely to affect the system.

Gli stili APA, Harvard, Vancouver, ISO e altri

8

Middleton, John F., Craig Arthur, Paul Van Ruth, Tim M. Ward, Julie L. McClean, Mathew E. Maltrud, Peter Gill, Andrew Levings e Sue Middleton. "El Niño Effects and Upwelling off South Australia". Journal of Physical Oceanography 37, n. 10 (1 ottobre 2007): 2458–77. http://dx.doi.org/10.1175/jpo3119.1.

Testo completo

Abstract (sommario):

Abstract To determine the possible importance of ENSO events along the coast of South Australia, an exploratory analysis is made of meteorological and oceanographic data and output from a global ocean model. Long time series of coastal sea level and wind stress are used to show that while upwelling favorable winds have been more persistent since 1982, ENSO events (i) are largely driven by signals from the west Pacific Ocean shelf/slope waveguide and not local meteorological conditions, (ii) can account for 10-cm changes in sea level, and (iii) together with wind stress, explain 62% of the variance of annual-averaged sea level. Thus, both local winds and remote forcing from the west Pacific are likely important to the low-frequency shelf edge circulation. Evidence also suggests that, since 1983, wintertime downwelling during the onset of an El Niño is reduced and the following summertime upwelling is enhanced. In situ data show that during the 1998 and 2003 El Niño events anomalously cold (10.5°–11.5°C) water is found at depths of 60–120 m and is more than two standard deviations cooler than the mean. A regression showed that averaged sea level can provide a statistically significant proxy for these subsurface temperature changes and indicates a 2.2°C decrease in temperature for the 10-cm decrease in sea level that was driven by the 1998 El Niño event. Limited current- meter observations, long sea level records, and output from a global ocean model were also examined and provide support for the hypothesis that El Niño events substantially reduce wintertime (but not summertime) shelf-edge currents. Further research to confirm this asymmetric response and its cause is required.

Gli stili APA, Harvard, Vancouver, ISO e altri

9

Job, Thomas, Dan Penny, Bree Morgan, Quan Hua, Patricia Gadd e Atun Zawadzki. "Multi-stage Holocene evolution of the River Murray Estuary, South Australia". Holocene 31, n. 1 (8 ottobre 2020): 50–65. http://dx.doi.org/10.1177/0959683620961487.

Testo completo

Abstract (sommario):

The River Murray Estuary, South Australia exhibits a morphology typical of a wave-dominated estuary and comprises two large, shallow central basin lakes – Lakes Alexandrina and Albert. Contested interpretations of the estuary’s limnological history and uncertainty surrounding the sustainability of current basin water usage practice warrant a robust investigation into how the system has evolved. Here we combine lithostratigraphic, geochemical and sedimentological evidence from a transect of sediment cores to reconstruct the sediment infill history of the system. We uncover multiple stages of sediment infill over the history of the system, associated with (1) the low gradient morphology of the estuary and lower river channel, (2) the mid- to late-Holocene sea-level regression and (3) anthropogenic modifications to the fluvio-estuarine system. We show that while estuarine conditions in the system were fully established during the mid-Holocene highstand (~6.4 kyr BP), central basin facies sedimentation was focussed further inland before prograding with the lowering of base level and shifting of tidal influence as sea-level fell. Central basin facies sedimentation within northern Lake Albert occurred from 5.4 to 4.0 cal kyr BP at ~0.25 cm yr-1. The uppermost accumulation of this unit was eroded by continued reduction in base level until sea-level regression concluded at 3.5 cal kyr BP. Barrage and weir installation (1940 CE) re-initiated and expanded central basin facies sedimentation in the estuary (~0.32 cm yr-1). Recently deposited sediments exhibit geochemical markers of increased trophy and more frequent acid sulfate soil acidification, exposing human impacts on the estuary.

Gli stili APA, Harvard, Vancouver, ISO e altri

10

Grose, Michael R., James S. Risbey, Mitchell T. Black e David J. Karoly. "Attribution of Exceptional Mean Sea Level Pressure Anomalies South of Australia in August 2014". Bulletin of the American Meteorological Society 96, n. 12 (dicembre 2015): S158—S162. http://dx.doi.org/10.1175/bams-eee_2014_ch32.1.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

11

Grose, Michael R., James S. Risbey, Mitchell T. Black e David J. Karoly. "Attribution of Exceptional Mean Sea Level Pressure Anomalies South of Australia in August 2014". Bulletin of the American Meteorological Society 96, n. 12 (1 dicembre 2015): S158—S162. http://dx.doi.org/10.1175/bams-d-15-00116.1.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

12

Dionne, J. C. "Holocene Relative Sea-Level Fluctuations in the St. Lawrence Estuary, Québec, Canada". Quaternary Research 29, n. 3 (maggio 1988): 233–44. http://dx.doi.org/10.1016/0033-5894(88)90032-4.

Testo completo

Abstract (sommario):

Between 7000 and 6000 yr B.P., relative sea level was as much as 5 m lower than today in the St. Lawrence estuary, Québec. A small transgression (Laurentian transgression) occurred between 5800 and 4400 yr B.P., which resulted in the construction of an 8- to 10-m terrace. About 3000 yr B.P., relative sea level was similar to present, and then a stillstand or a slight rise occurred during which a cliff (Micmac cliff) was cut into the emerged terrace. During a subsequent lowering of relative sea level (coastal emergence), a low aggradational terrace (Mitis terrace) was built between 2300 and 1500 yr B.P. at the base of the Micmac cliff. A new emergence curve for the south shore of the St. Lawrence estuary showing a mid-Holocene high stand of relative sea level is therefore proposed.

Gli stili APA, Harvard, Vancouver, ISO e altri

13

Sherwood, John E., Jim M. Bowler, Stephen P. Carey, John Hellstrom, Ian J. McNiven, Colin V. Murray-Wallace, John R. Prescott et al. "The Moyjil site, south-west Victoria, Australia: chronology". Proceedings of the Royal Society of Victoria 130, n. 2 (2018): 32. http://dx.doi.org/10.1071/rs18005.

Testo completo

Abstract (sommario):

An unusual shell deposit at Moyjil (Point Ritchie), Warrnambool, in western Victoria, has previously been dated at 67±10 ka and has features suggesting a human origin. If human, the site would be one of Australia’s oldest, justifying a redetermination of age using amino acid racemisation (AAR) dating of Lunella undulata (syn. Turbo undulatus) opercula (the dominant shellfish present) and optically stimulated luminescence (OSL) of the host calcarenite. AAR dating of the shell bed and four Last Interglacial (LIG) beach deposits at Moyjil and Goose Lagoon, 30 km to the west, confirmed a LIG age. OSL analysis of the host sand revealed a complex mixing history, with a significant fraction (47%) of grains giving an early LIG age (120–125 ka) using a three-component mixing model. Shell deposition following the LIG sea-level maximum at 120–125 ka is consistent with stratigraphic evidence. A sand layer immediately below the shell deposit gave an age of ~240 ka (i.e. MIS 7) and appears to have been a source of older sand incorporated into the shell deposit. Younger ages (~60–80 ka) are due to bioturbation before calcrete finally sealed the deposit. Uranium/thorium methods were not applicable to L. undulata opercula or an otolith of the fish Argyrosomus hololepidotus because they failed to act as closed systems. A U–Th age of 103 ka for a calcrete sheet within the 240 ka sand indicates a later period of carbonate deposition. Calcium carbonate dripstone from a LIG wave-cut notch gave a U–Th age of 11–14 ka suggesting sediment cover created a cave-like environment at the notch at this time. The three dating techniques have collectively built a chronology spanning the periods before and after deposition of the shell bed, which occurred just after the LIG sea-level maximum (120–125 ka).

Gli stili APA, Harvard, Vancouver, ISO e altri

14

Bell, Trevor, Martin J. Batterson, David GE Liverman e John Shaw. "A new late-glacial sea-level record for St. George's Bay, Newfoundland". Canadian Journal of Earth Sciences 40, n. 8 (1 agosto 2003): 1053–70. http://dx.doi.org/10.1139/e03-024.

Testo completo

Abstract (sommario):

A new relative sea-level curve is presented for St. George's Bay, southwest Newfoundland, based on (i) a revised stratigraphic framework and depositional model for glacial and marine deposits exposed in coastal sections and (ii) 19 new radiocarbon dates on shells from emerged and submerged marine deposits, including fossiliferous diamictons. The data produce a type B sea-level curve, falling steeply from an extrapolated marine limit of 105 m above sea level at 14.0 14C ka BP, passing below modern sea level at ~10.6 14C ka BP, to a lowstand of 25 m at ~9.4 14C ka BP, and rising again close to modern sea level by 5.0 14C ka BP. Marine limits in the northern part of the bay have lower elevations (2765 m) due to delayed ice retreat of up to 1.2 ka. Between 12.8 and at least 12.3 14C ka BP, glaciofluvial outwash graded to falling sea levels between 27 and 17 m above present throughout the bay, whereas lowstand deltas were constructed in sheltered locations at the outlets of major river systems, when sea level was 25 m below present. Establishment of the sea-level lowstand at ~9.4 14C ka BP is supported by new seismic data and radiocarbon dates from St. George's Bay and also from White Bear Bay on the south coast of Newfoundland. Short-term fluctuations in emergence rates of 12 m/century between 12.5 and 9.5 14C ka BP are attributed to variable eustatic sea-level rise, superimposed on a declining local glacio-isostatic adjustment.

Gli stili APA, Harvard, Vancouver, ISO e altri

15

Schmidt, Phillip W., e George E. Williams. "The Neoproterozoic climatic paradox: Equatorial palaeolatitude for Marinoan glaciation near sea level in South Australia". Earth and Planetary Science Letters 134, n. 1-2 (agosto 1995): 107–24. http://dx.doi.org/10.1016/0012-821x(95)00106-m.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

16

Pickett, J. W., C. H. Thompson, R. A. Kelley e D. Roman. "Evidence of High Sea Level during Isotope Stage 5c in Queensland, Australia". Quaternary Research 24, n. 1 (luglio 1985): 103–14. http://dx.doi.org/10.1016/0033-5894(85)90086-9.

Testo completo

Abstract (sommario):

Thirty-nine species of scleractinian corals have been recovered from under a high dune on the western (mainland) side of North Stradbroke Island, eastern Australia. The corals are associated with thin intertidal sediments and their good condition implies burial in situ and preservation in a saturated zone. Most likely this occurred as the coast prograded and a large dune advanced into the littoral zone, burying intertidal sediments and coral. The species assemblage indicates a sheltered environment but one open to the ocean without wide fluctuations in salinity. Three species yielded a mean 230Th/234U age of 105,000 yr B.P. which is significantly younger than the nearest Pleistocene corals at Evans Head, New South Wales. The corals provide evidence of a sea stand near present sea level during isotope Stage 5c, which is considerably higher than previously suggested for this period. Their good condition implies that the overlying parabolic dune is of comparable age and formed during that high stand of sea level. Also, the isotope age provides a maximum period for the development of giant podzols in the podzol chronosequences on coastal dunes in southern Queensland.

Gli stili APA, Harvard, Vancouver, ISO e altri

17

Pazandeh Masouleh, Zahra, David John Walker e John McCauley Crowther. "Sea breeze characteristics on two sides of a shallow gulf: study of the Gulf St Vincent in South Australia". Meteorological Applications 23, n. 2 (3 marzo 2016): 222–29. http://dx.doi.org/10.1002/met.1547.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

18

Sloss, Craig. "Holocene sea-level change in the South Wellesley Islands, Gulf of Carpentaria, Australia: a pilot study". Quaternary International 279-280 (novembre 2012): 454. http://dx.doi.org/10.1016/j.quaint.2012.08.1500.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

19

Hsieh, WW, e BV Hamon. "The El Nino-Southern Oscillation in south-eastern Australian waters". Marine and Freshwater Research 42, n. 3 (1991): 263. http://dx.doi.org/10.1071/mf9910263.

Testo completo

Abstract (sommario):

Using four decades of hydrographic data collected off the coast near Sydney, New South Wales, and sea-level data at Sydney, we studied the interannual variability in south-eastern Australian shelf waters. The first two empirical orthogonal function (EOF) modes of the band-pass-filtered 50-m-depth hydrographic data (temperature, T; salinity, S; nitrate, N; inorganic phosphate, P; and oxygen, O) and the sea level (SL) and adjusted sea level (ASL) data accounted respectively for 51 and 27% of the total variance. Both modes were significantly correlated with the Southern Oscillation Index (SOI). The first mode, with T, S, O and ASL varying in opposition to N and P, represented the internal or baroclinic response, associated with vertical displacements of the isopycnals. The second mode, with large in-phase fluctuations in SL and ASL but small changes in the hydrographic variables, represented mainly the external or barotropic response during the El Niiio-Southern Oscillation (ENSO). Three-year composites centred around seven ENSO warm episodes revealed that T, S, O and ASL were generally low and N, P, SL and SO1 were high in the year before each ENSO warm episode, but the former group rose while the latter group dropped in the year of the warm episode. The changes in the hydrographic variables at 50 m depth were consistent with relatively shallow isopycnals in the year before the ENSO warm episode, followed by a deepening of the isopycnals during the warm episode. Estimates of this downward displacement of isopycnals, as determined from T, N, P and O, were in the range 7-10 m. The geostrophic wind arising from the pressure fluctuations during ENSO is proposed as a probable cause for the vertical displacement of the isopycnals. In the year before the warm episode, the low air pressure over Australia would produce a clockwise geostrophic wind around south-eastern Australia, generating offshore Ekman transport and coastal upwelling. During the warm episode, air pressure over Australia rises, the geostrophic wind reverses, and downward movement of the isopycnals would occur off south-eastern Australia.

Gli stili APA, Harvard, Vancouver, ISO e altri

20

Sloss, Craig R., Luke Nothdurft, Quan Hua, Shoshannah G. O’Connor, Patrick T. Moss, Daniel Rosendahl, Lynda M. Petherick et al. "Holocene sea-level change and coastal landscape evolution in the southern Gulf of Carpentaria, Australia". Holocene 28, n. 9 (26 giugno 2018): 1411–30. http://dx.doi.org/10.1177/0959683618777070.

Testo completo

Abstract (sommario):

A revised Holocene sea-level history for the southern Gulf of Carpentaria is presented based on new data from the South Wellesley Archipelago and age recalibration of previous research. Results confirm that rising sea levels during the most recent post-glacial marine transgression breached the Arafura Sill ca. 11,700 cal. yr BP. Sea levels continued to rise to ca. –30 m by 10,000 cal. yr BP, leading to full marine conditions. By 7700 cal. yr BP, sea-level reached present mean sea-level (PMSL) and continued to rise to an elevation of between 1.5 m and 2 m above PMSL. Sea level remained ca. + 1.5 between 7000 and 4000 cal. yr BP, followed by rapid regression to within ± 0.5 m of PMSL by ca. 3500 cal. yr BP. When placed into a wider regional context results from this study show that coastal landscape evolution in the tropical north of Australia was not only dependent on sea-level change but also show a direct correlation with Holocene climate variability. Specifically, the formation and preservation of beach-rock deposits, intertidal successions, beach and chenier ridge systems hold valuable sea-level and Holocene climate proxies that can contribute to the growing research into lower latitude Holocene sea-level and climate histories.

Gli stili APA, Harvard, Vancouver, ISO e altri

21

McMinn, Andrew. "Quaternary Coastal Evolution and Vegetation History of Northern New South Wales, Australia, Based on Dinoflagellates and Pollen". Quaternary Research 38, n. 3 (novembre 1992): 347–58. http://dx.doi.org/10.1016/0033-5894(92)90043-i.

Testo completo

Abstract (sommario):

AbstractThe Richmond River Valley of northern N.S.W. contains a late Pleistocene succession dating back to approximately 250,000 yr B.P. Dinoflagellate and spore-pollen assemblages from the lowest interval, the lower “Dungarubba Clay” of Drury (1982), indicate deposition in a restricted estuarine environment at approximately 250,000 yr. Deposition in the overlying interval, the upper “Dungarubba Clay” and “Gundurimba Clay”, at approximately 120,000 yr B.P., began in a restricted estuary, but rising sea level caused inundation and deposition in a more open, marine-dominated environment. Dinoflagellate cyst assemblages from the last interglaciation (stage 5) are interpreted by analogy with those from the morphologically similar, modern Broken Bay, N.S.W. They are indicative of an open, marine-dominated environment and imply that barrier formation in the Richmond River Valley, and possibly elsewhere in northern N.S.W., did not commence until after the initial postglacial transgression. Synchronous changes in sea level and rainforest development suggest that there was no significant time lag between climate and sea-level change.

Gli stili APA, Harvard, Vancouver, ISO e altri

22

Huyer, A., RL Smith, PJ Stabeno, JA Church e NJ White. "Currents off south-eastern Australia: results from the Australian coastal experiment". Marine and Freshwater Research 39, n. 3 (1988): 245. http://dx.doi.org/10.1071/mf9880245.

Testo completo

Abstract (sommario):

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.

Gli stili APA, Harvard, Vancouver, ISO e altri

23

Schrale, G., R. Boardman e M. J. Blaskett. "Investigating Land Based Disposal of Bolivar Reclaimed Water, South Australia". Water Science and Technology 27, n. 1 (1 gennaio 1993): 87–96. http://dx.doi.org/10.2166/wst.1993.0022.

Testo completo

Abstract (sommario):

The Bolivar Sewage Treatment Works (STW) processes the urban and industrial sewage from the northern and eastern suburbs of Adelaide. The treatment capacity is equivalent to the sewage production of 1.1 million people. The disposal of more than 40 000 ML of reclaimed water into the sea has caused a progressive degradation of about 950 ha of seagrass beds which threatens the sustainability of the fisheries and marine ecosystems of Gulf St. Vincent. The current practice will no longer be viable to achieve compliance with the SA Marine Environment Protection Act, 1990. A Inter-Departmental Working Party recommmended that the Bolivar reclaimed water be disposed by irrigation of suitable land on the coastal plains north of Adelaide. They proposed the construction of two pipelines: a 12 km long pipeline to extend the distribution of reclaimed water in the most intense portion of the 3 500 hectares of irrigated horticulture on the Northern Adelaide Plains, and a second, 18 km long pipeline to deliver the remainder to a more northerly site for irrigation of an estimated 4 000 hectares of hardwood plantations. The paper summarizes the findings as they relate to public health, environmental, technical and financial aspects of land based disposal. Land based disposal would completely eliminate the marine degradation and also arrest the over-use of the NAP underground water resources for horticulture. The total net costs over thirty years for land based disposal are about $ 21.8 million. The ‘horticultural' pipeline of the land based disposal scheme is expected to be commercially viable. A shortfall in revenue from the afforestation component is expected and may need to be considered as an environmental cost of ceasing marine disposal.

Gli stili APA, Harvard, Vancouver, ISO e altri

24

Smale, Dan A., e Thomas Wernberg. "Population structure of the purple sea urchin Heliocidaris erythrogramma along a latitudinal gradient in south-west Australia". Journal of the Marine Biological Association of the United Kingdom 94, n. 5 (13 dicembre 2013): 1033–40. http://dx.doi.org/10.1017/s0025315413001604.

Testo completo

Abstract (sommario):

Sea urchins are key herbivores in many coastal ecosystems. The purple sea urchin, Heliocidaris erythrogramma, is widely distributed across temperate Australia where it exhibits considerable plasticity in feeding behaviour and ecophysiology. In this study we examined H. erythrogramma populations on subtidal reefs along ~4° of latitude in south-west Australia. We used a multi-factorial survey design to assess variability in H. erythrogramma abundances between locations (>200 km part), sites (≥1 km apart) and habitat types (reef flats and slopes). We also examined spatial variability in urchin size, condition (measured by gonad index), and the relative abundances of two co-occurring subspecies. Urchin densities were generally low and did not vary between locations, but did vary between habitat types and amongst sites. Site-level variability in urchin size and condition was also pronounced. The southernmost population comprised smaller individuals and greater relative abundance of the H. e. erythrogramma subspecies, which is abundant on the east coast of Australia. We observed no indication of population-level responses to a recent extreme warming event that impacted the wider ecology of the region, but further investigation into the effects of both gradual warming and short-term climatic events on the ecology of H. erythrogramma and other key herbivores is required.

Gli stili APA, Harvard, Vancouver, ISO e altri

25

Oliver, Thomas SN, Colin V. Murray-Wallace e Colin D. Woodroffe. "Holocene shoreline progradation and coastal evolution at Guichen and Rivoli Bays, southern Australia". Holocene 30, n. 1 (19 settembre 2019): 106–24. http://dx.doi.org/10.1177/0959683619875815.

Testo completo

Abstract (sommario):

Prograded barrier systems record shoreline behaviour and palaeoenvironmental information. The Guichen Bay Holocene embayment fill succession in South Australia has been subject to several prominent studies; however, several important unanswered questions remained regarding the timing of the older ridge sets at this site. Additional Optically Stimulated Luminescence (OSL) dating indicates that progradation commenced in the southeastern corner of the plain ~7300 years ago and was rapid between ~5800 and ~5000 years ago. To augment this record, three OSL dating transects were constructed at nearby Rivoli Bay in the north, central and south. Rapid progradation occurred in the south and then north of the Rivoli plain until ~5000 years ago. Steady progradation occurred in the centre of the plain between ~5000 years ago and present. Rapid shoreline progradation at Guichen and Rivoli Bays before ~5000 years ago was due to the input of sediment from the erosion of Robe and Woakwine Ranges and the inner continental shelf as sea levels rose to present. Raised beach strata imaged with Ground Penetrating Radar (GPR) at Rivoli Bay suggest a sea-level highstand of +2 m above present ~3500 years ago, steadily falling and reaching the present ~1000 years ago. This concurs with evidence from Guichen Bay and may have promoted shoreline progradation. Sediment infilling of Guichen and Rivoli Bays and the fall in sea level restricted the marine corridor between the Woakwine and Robe Ranges to a narrow channel by ~4000 and ~2000 years in the north and south, respectively. Holocene shoreline behaviour was influenced by changing sediment supply and shoreline reorientation with changing wave refraction patterns.

Gli stili APA, Harvard, Vancouver, ISO e altri

26

McGowan, Sarah A., e Robert GV Baker. "How past sea-level changes can inform future planning: A case study from the Macleay River estuary, New South Wales, Australia". Holocene 24, n. 11 (20 agosto 2014): 1591–601. http://dx.doi.org/10.1177/0959683614544055.

Testo completo

Abstract (sommario):

Climate change poses many challenges for the future management and development of the coastal zone. Uncertainties in the rate of future sea-level rise reduce our ability to project potential future impacts. This study seeks to further develop the past–present–future methodology proposed in Baker and McGowan and apply it to an additional case study, the Macleay River estuary, New South Wales (NSW), Australia. The past–present–future methodology uses evidence from the past, the Holocene and Pleistocene, to formulate a response function that can be used to project future sea-level heights. Three scenarios for 2100 were developed to emphasise the uncertainties surrounding future sea levels and the need to consider multiple sea-level rise scenarios when planning for the future: a best case (90 cm rise), mid-case (2.6 m rise) and worst case (5 m rise). Light detection and ranging (LiDAR) data were used to project each of the three scenarios onto the case study area of South West Rocks. The methodology was tested by using shell samples extracted from cores which were AMS dated to determine whether or not Holocene estuarine conditions correlated with the proposed future sea-level rise inundation scenarios. We also conducted an audit of potentially affected infrastructure and land uses, and proposed possible future adaptation strategies for the case study area.

Gli stili APA, Harvard, Vancouver, ISO e altri

27

Sloss, Craig R., Brian G. Jones, Colin V. Murray-Wallace e Charles E. McClennen. "Holocene Sea Level Fluctuations and the Sedimentary Evolution of a Barrier Estuary: Lake Illawarra, New South Wales, Australia". Journal of Coastal Research 215 (settembre 2005): 943–59. http://dx.doi.org/10.2112/03-0110.1.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

28

Gouramanis, C., J. Dodson, D. Wilkins, P. De Deckker e B. M. Chase. "Holocene palaeoclimate and sea level fluctuation recorded from the coastal Barker Swamp, Rottnest Island, south-western Western Australia". Quaternary Science Reviews 54 (ottobre 2012): 40–57. http://dx.doi.org/10.1016/j.quascirev.2012.05.007.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

29

Hou, B., N. F. Alley, L. A. Frakes, L. Stoian e W. M. Cowley. "Eocene stratigraphic succession in the Eucla Basin of South Australia and correlation to major regional sea-level events". Sedimentary Geology 183, n. 3-4 (gennaio 2006): 297–319. http://dx.doi.org/10.1016/j.sedgeo.2005.10.007.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

30

Lough, Janice M., e Alistair J. Hobday. "Observed climate change in Australian marine and freshwater environments". Marine and Freshwater Research 62, n. 9 (2011): 984. http://dx.doi.org/10.1071/mf10272.

Testo completo

Abstract (sommario):

The consequences of human activities increasing concentrations of atmospheric greenhouse gases are already being felt in marine and terrestrial environments. More energy has been trapped in the global climate system, resulting in warming of land and sea temperatures. About 30% of the extra atmospheric carbon dioxide has been absorbed by the oceans, increasing their acidity. Thermal expansion and some melting of land-based ice have caused sea level to rise. Significant climate changes have now been observed across Australia and its coastal seas. The clearest signal is the warming of air and sea temperatures and the rates of warming have accelerated since the mid-20th century. Ocean warming has been higher than the global average around Australia, especially off south-eastern Australia. Changes in Australia’s hydrological regime are more difficult to differentiate from the high natural inter-annual variability. Recent trends towards drier winters in south-western Western Australia and part of southern Australia appear, however, to be largely attributable to human-induced climate change. Even without significant changes in average rainfall, warmer temperatures increase evaporative losses, enhance the intensity of recent droughts and reduce river flows. Sustained and coordinated monitoring of the physical environment, especially lacking for Australia’s freshwater ecosystems, is important to assess the magnitude and biological consequences of ongoing changes.

Gli stili APA, Harvard, Vancouver, ISO e altri

31

Fahad, Abdullah A., Natalie J. Burls, Erik T. Swenson e David M. Straus. "The Influence of South Pacific Convergence Zone Heating on the South Pacific Subtropical Anticyclone". Journal of Climate 34, n. 10 (maggio 2021): 3787–98. http://dx.doi.org/10.1175/jcli-d-20-0509.1.

Testo completo

Abstract (sommario):

AbstractSubtropical anticyclones and midlatitude storm tracks are key components of the large-scale atmospheric circulation. Focusing on the Southern Hemisphere, the seasonality of the three dominant subtropical anticyclones, situated over the South Pacific, South Atlantic, and south Indian Ocean basins, has a large influence on local weather and climate within South America, southern Africa, and Australia, respectively. Generally speaking, sea level pressure within the Southern Hemisphere subtropics reaches its seasonal maximum during the winter season when the Southern Hemisphere Hadley cell is at its strongest. One exception to this is the seasonal evolution of the South Pacific subtropical anticyclone. While winter maxima are seen in the South Atlantic and south Indian subtropical anticyclones, the South Pacific subtropical anticyclone reaches its seasonal maximum during local spring with elevated values extending into summer. In this study, we investigate the hypothesis that the strength of the austral summer South Pacific subtropical anticyclone is largely due to heating over the South Pacific convergence zone. Using added-cooling and added-heating atmospheric general circulation model experiments to artificially change the strength of austral summer diabatic heating over the South Pacific convergence zone, our results show that increased heating, through increased upper-level divergence, triggers a Rossby wave train that extends into the Southern Hemisphere midlatitudes. This propagating Rossby wave train creates a high and low sea level pressure pattern that projects onto the center of the South Pacific subtropical anticyclone to intensify its area and strength.

Gli stili APA, Harvard, Vancouver, ISO e altri

32

Murray, AJ. "A new low-cost hairtube design for the detection of the spotted-tailed quoll Dasyurus maculatus in south-eastern Australia." Australian Mammalogy 27, n. 1 (2005): 81. http://dx.doi.org/10.1071/am05081.

Testo completo

Abstract (sommario):

THE spotted-tailed quoll (Dasyurus maculatus) is the largest carnivorous marsupial extant on mainland Australia, where it has a fragmented distribution in forested habitats in the eastern part of the continent. This species is also found in Tasmania. D. maculatus have been found in a wide variety of forest types from sea level to over 1400 m above sea level, in areas generally receiving in excess of 600 mm of rainfall (Mansergh 1983). The distribution of D. maculatus is believed to have declined by over 50% following European settlement (Mansergh 1983).

Gli stili APA, Harvard, Vancouver, ISO e altri

33

Bamber, J., e R. Riva. "The sea level fingerprint of recent ice mass fluxes". Cryosphere 4, n. 4 (21 dicembre 2010): 621–27. http://dx.doi.org/10.5194/tc-4-621-2010.

Testo completo

Abstract (sommario):

Abstract. The sea level contribution from glacial sources has been accelerating during the first decade of the 21st Century (Meier et al., 2007; Velicogna, 2009). This contribution is not distributed uniformly across the world's oceans due to both oceanographic and gravitational effects. We compute the sea level signature for ice mass fluxes due to changes in the gravity field, Earth's rotation and related effects for the nine year period 2000–2008. Mass loss from Greenland results in a relative sea level (RSL) reduction for much of North Western Europe and Eastern Canada. RSL rise from this source is concentrated around South America. Losses in West Antarctica marginally compensate for this and produce maxima along the coastlines of North America, Australia and Oceania. The combined far-field pattern of wastage from all ice melt sources, is dominated by losses from the ice sheets and results in maxima at latitudes between 20° N and 40° S across the Pacific and Indian Oceans, affecting particularly vulnerable land masses in Oceania. The spatial pattern of RSL variations from ice mass losses used in this study is time-invariant and cumulative. Thus, sea level rise, based on the gravitational effects from the ice losses considered here, will be amplified for this sensitive region.

Gli stili APA, Harvard, Vancouver, ISO e altri

34

Parker, Albert. "Minimum 60 years of recording are needed to compute the sea level rate of rise in the Western South Pacific". Nonlinear Engineering 3, n. 1 (1 marzo 2014): 1–10. http://dx.doi.org/10.1515/nleng-2013-0011.

Testo completo

Abstract (sommario):

Abstract Sea levels generally oscillate with multi-decadal periodicities worldwide with up to the quasi-60 years detected in many tide gauges. Nevertheless, the most part of the literature on sea levels computes apparent rates of rise of sea levels much larger than the legitimate by using short time windows in selected locations only covering part of a valley-to-peak of this multi-decadal oscillation. It is shown in this paper that along the Pacific coast of Australia the sea levels oscillate with a frequency close to the Southern Ocean Index (SOI) oscillation of 19 years and a lower frequency of about 60 years. The rates of rise of sea levels computed by linear fitting of the data recorded since the early 1990s in selected locations of the Australian Pacific coastline and in the tropical Pacific islands are from a valley of the peak and valley oscillations and are much higher than the legitimate long term values.

Gli stili APA, Harvard, Vancouver, ISO e altri

35

Bamber, J., e R. Riva. "The sea level fingerprint of 21st century ice mass fluxes". Cryosphere Discussions 4, n. 3 (3 settembre 2010): 1593–606. http://dx.doi.org/10.5194/tcd-4-1593-2010.

Testo completo

Abstract (sommario):

Abstract. The sea level contribution from glacial sources has been accelerating during the 21st century (Meier et al., 2007; Velicogna, 2009). This contribution is not distributed uniformly across the world's oceans due to both oceanographic and gravitational effects. We compute the sea level signature of 21st century ice mass fluxes due to changes in the gravity field, Earth's rotation and related effects. Mass loss from Greenland results in a relative sea level (RSL) reduction for much of North Western Europe and Eastern Canada. RSL rise from this source is concentrated around South America. Losses in West Antarctica marginally compensate for this and produce maxima along the coastlines of North America, Australia and Oceania. The combined far-field pattern of wastage from all ice melt sources, is dominated by losses from the ice sheets and results in maxima at latitudes between 20° N and 40° S across the Pacific and Indian Oceans, affecting particularly vulnerable land masses in Oceania. The spatial pattern of RSL variations due to the observed ice mass loss is temporally invariant. Thus, sea level rise, based on the land ice losses considered here, will be amplified for this sensitive region.

Gli stili APA, Harvard, Vancouver, ISO e altri

36

Giunipero, Emma M., e Allan J. Clarke. "Estimation of the Effect of Eddies on Coastal El Niño Flows Using Along-Track Satellite Altimeter Data". Journal of Physical Oceanography 43, n. 6 (1 giugno 2013): 1209–24. http://dx.doi.org/10.1175/jpo-d-12-0109.1.

Testo completo

Abstract (sommario):

Abstract Previous work has shown that the El Niño sea level signal leaks through the gappy western equatorial Pacific to the coasts of western and southern Australia. South of about 22°S, in the region of the Leeuwin Current, the amplitude of this El Niño signal falls. Using coastal sea level measurements and along-track altimetry data from the Ocean Topography Experiment (TOPEX)/Poseidon, Jason-1, and OSTM/Jason-2 satellites, this study finds that the interannual divergence of the eddy momentum flux D′ is correlated with the southward along-shelf sea level amplitude decay, consistent with the eddies removing energy from the large-scale sea level signal. The quantity D′ is also correlated with the interannual flow with a surprisingly short dissipation time scale of only 2 days, much shorter than the interannual time scale. A similar analysis off the western coast of South America, site of the originally named “El Niño” current, was carried out. Interannual sea level decay along the shelf edge is observed, and the interannual southward flow along the shelf edge is found to be highly positively correlated with the along-shelf sea level decay with a dissipation time scale of a few days. Dynamics similar to the Australian case likely apply.

Gli stili APA, Harvard, Vancouver, ISO e altri

37

Young, Catherine J., e Peter B. Mcquillan. "Redescription of the little-known Australian geometrid moth Palleopa innotata Walker, 1866 (Lepidoptera: Geometridae: Ennominae)". Insect Systematics & Evolution 32, n. 3 (2001): 263–78. http://dx.doi.org/10.1163/187631201x00209.

Testo completo

Abstract (sommario):

AbstractThe previously overlooked geometrid genus Palleopa Walker, which includes one described, widespread species: innotata, is reviewed. The genus has an eastern Bassian distribution, south of latitude 28°S, in the moist forests and woodlands of south eastern Australia from sea level to over 1000m. The distinctive larvae feed on the foliage of Eucalyptus trees. The immature stages are described and the life cycle is illustrated for the first time.

Gli stili APA, Harvard, Vancouver, ISO e altri

38

Kuhn, M., D. Tuladhar e R. Corner. "Visualising the spatial extent of predicted coastal zone inundation due to sea level rise in south-west Western Australia". Ocean & Coastal Management 54, n. 11 (novembre 2011): 796–806. http://dx.doi.org/10.1016/j.ocecoaman.2011.08.005.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

39

TAYLOR, BRUCE M., BEN P. HARMAN e MATTHEW INMAN. "Scaling-Up, Scaling-Down, and Scaling-Out: Local Planning Strategies for Sea-Level Rise in New South Wales, Australia". Geographical Research 51, n. 3 (9 luglio 2013): 292–303. http://dx.doi.org/10.1111/1745-5871.12011.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

40

Williams, George E., e Victor A. Gostin. "Late Cryogenian glaciation in South Australia: Fluctuating ice margin and no extreme or rapid post-glacial sea-level rise". Geoscience Frontiers 10, n. 4 (luglio 2019): 1397–408. http://dx.doi.org/10.1016/j.gsf.2019.02.002.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

41

Azmy, Karem, e Denis Lavoie. "High-resolution isotope stratigraphy of the Lower Ordovician St. George Group of western Newfoundland, Canada: implications for global correlation". Canadian Journal of Earth Sciences 46, n. 6 (giugno 2009): 403–23. http://dx.doi.org/10.1139/e09-032.

Testo completo

Abstract (sommario):

The Lower Ordovician St. George Group of western Newfoundland consists mainly of shallow-marine-platform carbonates (∼500 m thick). It is formed, from bottom to top, of the Watts Bight, Boat Harbour, Catoche, and Aguathuna formations. The top boundary of the group is marked by the regional St. George Unconformity. Outcrops and a few cores from western Newfoundland were sampled at high resolution and the extracted micritic materials were investigated for their petrographic and geochemical criteria to evaluate their degree of preservation. The δ13C and δ18O values of well-preserved micrite microsamples range from –4.2‰ to 0‰ (VPDB) and from –11.3‰ to –2.9‰ (VPDB), respectively. The δ13Ccarb profile of the St. George Group carbonates reveals several negative shifts, which vary between ∼2‰ and 3‰ and are generally associated with unconformities–disconformities or thin shale interbeds, thus reflecting the effect of or link with significant sea-level changes. The St. George Unconformity is associated with a negative δ13Ccarb shift (∼2‰) on the profile and correlated with major lowstand (around the end of Arenig) on the local sea-level reconstruction and also on those from the Baltic region and central Australia, thus suggesting that the St. George Group Unconformity might have likely had an eustatic component that contributed to the development–enhancement of the paleomargin. Other similar δ13Ccarb shifts have been recorded on the St. George profile, but it is hard to evaluate their global extension due to the low resolution of the documented global Lower Ordovician (Tremadoc – middle Arenig) δ13Ccarb profile.

Gli stili APA, Harvard, Vancouver, ISO e altri

42

Prahalad, Vishnu, Jamie B. Kirkpatrick, John Aalders, Scott Carver, Joanna Ellison, Violet Harrison-Day, Peter McQuillan, Brigid Morrison, Alastair Richardson e Eric Woehler. "Conservation ecology of Tasmanian coastal saltmarshes, south-east Australia – a review". Pacific Conservation Biology 26, n. 2 (2020): 105. http://dx.doi.org/10.1071/pc19016.

Testo completo

Abstract (sommario):

Temperate Australian saltmarshes, including those in the southern island state of Tasmania, are considered to be a threatened ecological community under Australian federal legislation. There is a need to improve our understanding of the ecological components, functional relationships and threatening processes of Tasmanian coastal saltmarshes and distil research priorities that could assist recovery actions. A semisystematic review of the literature on Tasmanian coastal saltmarshes supported by expert local knowledge identified 75 studies from 1947 to 2019. Existing understanding pertains to saltmarsh plants, soils, invertebrates and human impacts with ongoing studies currently adding to this knowledge base. Several knowledge gaps remain, and the present review recommends six key priority areas for research: (1) citizen science–organised inventory of (initially) saltmarsh birds, plants and human impacts with the potential for expansion of datasets; (2) use of saltmarsh by marine transient species including fish and decapods; (3) use of saltmarsh by, and interactions with, native and introduced mammals; (4) invertebrates and their interactions with predators (e.g. birds, fish) and prey (e.g. insects, plants, detritus); (5) historic saltmarsh loss and priority areas for conservation; (6) monitoring changes to saltmarsh due to both localised human impacts (e.g. grazing, eutrophication, destruction) and global change factors (e.g. climate change, sea-level rise). Addressing these research priorities will help in developing a better understanding of the ecological character of Tasmanian coastal saltmarshes and improve their conservation management.

Gli stili APA, Harvard, Vancouver, ISO e altri

43

Parent, Michel, e Serge Occhietti. "Late Wisconsinan Deglaciation and Champlain Sea Invasion in the St. Lawrence Valley, Québec". Géographie physique et Quaternaire 42, n. 3 (18 dicembre 2007): 215–46. http://dx.doi.org/10.7202/032734ar.

Testo completo

Abstract (sommario):

ABSTRACT Champlain Sea history is directly linked to Late Wisconsinan deglacial episodes. Champlain Sea Phase I (Charlesbourg Phase) began in the Québec area at about 12.4 ka. It represented a western extension of the Goldthwait Sea between remnant Appalachian ice masses and the Laurentide Ice Sheet. Further south, at about the same time, in the Appalachian uplands and piedmont, high-level glacial lakes were impounded by the ice-front during glacial retreat toward NNW: lakes Vermont, Memphrémagog and Mégantic. Lowlands of the Upper St. Lawrence and Lake Champlain valleys were progressively deglaciated and inundated by Lake Iroquois and Lake Vermont. At about 12.1 ka, these two lakes coalesced and formed a single water-body, here referred to as Lake Candona. After the Ulverton-Tingwick Moraine was constructed, this lake extended northeastward onto the Appalachian piedmont where varved sediments containing Candona subtriangulata underlie marine clays. Current data and interpretations bring into question the former concept of the Highland Front Moraine System. The invasion of the main basin, or Champlain Sea Phase II, began around 12 ka. Replacement of Lake Candona by the sea resulted in a fall of about 60 m in water levels. Champlain Sea Phase III began at the end of the Saint-Narcisse episode, at about 10.8 ka. At this time marine waters were able to enter valleys of the Laurentian Highlands where brackish or fresh paramarine basins developed.

Gli stili APA, Harvard, Vancouver, ISO e altri

44

Zhang, Shunxin, e Christopher R. Barnes. "Arenigian (Early Ordovician) sea-level history and the response of conodont communities, western Newfoundland". Canadian Journal of Earth Sciences 41, n. 7 (1 luglio 2004): 843–65. http://dx.doi.org/10.1139/e04-036.

Testo completo

Abstract (sommario):

Four cluster analyses were performed, which recognized 17 conodont communities in the Arenigian (Lower Ordovician) of western Newfoundland. The analyses include 69 598 identifiable conodont specimens recovered from 153 conodont-bearing samples from four stratigraphical sections representing the environmental settings of the platform, upper proximal slope, lower proximal slope, and distal slope. The distribution of conodont communities along the platform to slope environmental gradient shows that sea-level changes simultaneously affected the development and replacement of the conodont communities in the different facies. The pattern of change in conodont communities allows an interpretation of sea-level change that is correlated precisely into the detailed graptolite biozonation. A gradual transgression lasted most of Tetragraptus approximatus Zone time, which was followed by a brief regression; a transgressionregression cycle occurred in the T. akzharensis Zone time; a major transgression caused a highstand during the entire Pendeograptus fruticosus Zone time, which was followed by a major regression in the early Didymograptus bifidus Zone time; Isograptus victoriae lunatus Zone time included repetitive oscillations of sea level; a severe regression in the earliest I. i. victoriae Zone time was represented by the St. George unconformity on the platform and the Bed 12 megaconglomerate on the slope, reaching the lowest sea level during the I. i. maximus Zone time. The Arenigian sea-level curve developed by this study only partly agrees with that from the Baltic region and central Australia based on trilobite communities.

Gli stili APA, Harvard, Vancouver, ISO e altri

45

Switzer, Adam D., Kevin Pucillo, Rabea A. Haredy, Brian G. Jones e Edward A. Bryant. "Sea Level, Storm, or Tsunami: Enigmatic Sand Sheet Deposits in a Sheltered Coastal Embayment from Southeastern New South Wales, Australia". Journal of Coastal Research 214 (luglio 2005): 655–63. http://dx.doi.org/10.2112/04-0177.1.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

46

MURRAY-WALLACE, C. V., B. P. BROOKE, J. H. CANN, A. P. BELPERIO e R. P. BOURMAN. "Whole-rock aminostratigraphy of the Coorong Coastal Plain, South Australia: towards a 1 million year record of sea-level highstands". Journal of the Geological Society 158, n. 1 (gennaio 2001): 111–24. http://dx.doi.org/10.1144/jgs.158.1.111.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

47

Ryan, Deirdre D., Robert P. Bourman, David M. Price e Colin V. Murray-Wallace. "Identification of a penultimate interglacial (marine isotope stage 7) alluvium in South Australia and its climatic and sea-level implications". Transactions of the Royal Society of South Australia 142, n. 2 (3 luglio 2018): 208–23. http://dx.doi.org/10.1080/03721426.2018.1509415.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

48

Bryars, Simon R., e Mark Adams. "An allozyme study of the blue swimmer crab, Portunus pelagicus (Crustacea : Portunidae), in Australia: stock delineation in southern Australia and evidence for a cryptic species in northern waters". Marine and Freshwater Research 50, n. 1 (1999): 15. http://dx.doi.org/10.1071/mf98075.

Testo completo

Abstract (sommario):

Allozyme analysis was used to examine the species-level systematics and stock structure of the Australian blue swimmer crab Portunus pelagicus. Fifty-seven crabs from eight sites were screened in an overview study for allozyme variation at 35 loci. This overview study revealed the presence of two species, differing at a Nei D of 0.14 (2% fixed differences), in the Darwin region of northern Australia. One of these species corresponds to the common P. pelagicus found throughout Australia, whereas the other is most likely either an undescribed ‘cryptic’ species, or the east-Asian species P. trituberculatus. In total, 609 P. pelagicus from 11 sites covering three regions in South Australia and two regions in the Northern Territory were then genotyped at seven polymorphic loci and these data assessed, using goodness- of-fit and F-statistics, for the existence of subpopulations. Four discrete subpopulations could be discerned, namely West Coast, Spencer Gulf, and Gulf St Vincent in South Australia, and Darwin–Gove in the Northern Territory. No evidence of population substructuring among sites within each subpopulation was evident from the allozyme data. The results support the current recognition of the three South Australian regions as separate stocks, and suggest that a taxonomic revision of Indo-Pacific Portunus is warranted.

Gli stili APA, Harvard, Vancouver, ISO e altri

49

Gorman, Daniel, e Cameron Dixon. "Reducing discards in a temperate prawn trawl fishery: a collaborative approach to bycatch research in South Australia". ICES Journal of Marine Science 72, n. 9 (13 ottobre 2015): 2609–17. http://dx.doi.org/10.1093/icesjms/fsv147.

Testo completo

Abstract (sommario):

Abstract We present the outcomes of a collaborative research programme tasked with reducing bycatch, and thus discards in a temperate Australian prawn trawl fishery. Sea trials in the Gulf of St Vincent, South Australia, assessed the performance of a modified trawlnet that incorporated a rigid polyethylene grid and a T90-mesh codend. Compared with conventional designs, the modified net yielded marked reductions in bycatch (cumulatively >81% by weight), with pronounced decreases in sponge (92%), elasmobranchs (80%), teleost fish (71%), molluscs (61%), and crustaceans (78%). Using commercial logbook data, we estimate that the use of modified nets could reduce discards by ∼240 tons per year. This outcome was achieved with moderate declines in the catch rate (kg h−1) of the target species, Western King Prawn (mean ∼15%), of which almost all were small adults of low commercial value. Adoption of the modified net by industry was realized in March 2012, because it met environmental objectives (i.e. reducing bycatch and improving public perceptions of sustainability), reduced prawn damage, demonstrated commensurate financial returns, and engaged stakeholders throughout the development process. Overall, the project provides a useful example of bycatch research with demonstrable outcomes of improving the ecological and economic sustainability of prawn harvests.

Gli stili APA, Harvard, Vancouver, ISO e altri

50

Stephenson, Sarah A., Tiffanie M. Nelson, Claire Streten, Karen S. Gibb, David Williams, Paul Greenfield e Anthony A. Chariton. "Sea-level rise in northern Australia's Kakadu National Park: a survey of floodplain eukaryotes". Marine and Freshwater Research 69, n. 7 (2018): 1134. http://dx.doi.org/10.1071/mf18067.

Testo completo

Abstract (sommario):

Forecasted climate-change models predict that much of northern Australia’s coastal habitats will be in retreat because of saltwater intrusion (SWI) from sea-level rise. A region of primary concern is the nutrient-rich and biodiverse floodplains of world heritage-listed Kakadu National Park (KNP). To understand the implications of SWI, we need fundamental baseline information for floodplain biota from the South Alligator River, KNP, northern Australia, and informative data on how increased and prolonged exposure to salt is likely to shape the eukaryotic community. To assist in addressing these key knowledge gaps, we used amplicon sequencing to examine the composition of eukaryotic soil communities from the South Alligator River floodplain, an ecologically important area at the ‘coalface’ of sea-level rise. Samples were obtained from three river zones and three floodplain morphologies, capturing a wide range of habitats and episodic exposures to both saltwater and freshwater. We found that both the floodplain morphology and positioning along the river significantly influenced eukaryotic composition. However, the influence of these variables varied greatly among the floodplain morphologies, with correlative evidence suggesting that both salinity and pH played a dominant role in shaping communities within lower parts of the floodplain, with this being particularly evident in those regions subjected to major tidal influence (estuarine funnel and sinuous, and cuspate).

Gli stili APA, Harvard, Vancouver, ISO e altri

Articoli di riviste sul tema "Sea level South Australia St"

Cita una fonte nei formati APA, MLA, Chicago, Harvard e in molti altri stili