https://ogma.newcastle.edu.au/vital/access/ /manager/Index en-au 5 https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:40517 Wed 19 Apr 2023 10:00:48 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:17137 13C enrichment at high altitudes (colder temperatures) and slow drip rates. The results obtained support modelling and laboratory cave analogue experiments that indicate temperature, drip rate, pCO₂ and supersaturation are important factors controlling stable isotope fractionation, but also stress the significance of ventilation and evaporation in the cave environment. It is proposed that the effects on stable isotope ratios observed along the altitudinal gradient can be analogues for glacial to interglacial temperature changes in regions which were extensively glaciated in the past.]]> Wed 11 Apr 2018 14:51:14 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:13592 Wed 11 Apr 2018 12:52:13 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:13485 Wed 11 Apr 2018 12:01:50 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:31155 Wed 11 Apr 2018 11:49:04 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:46828 18O, δ²H) and carbon (δ¹³C), radioisotopes (³H, ¹⁴C) and other geochemical indicators were used to assess sources of water and salinity in the shallow groundwater. Groundwater in the upper aquifer was predominantly Ca-HCO₃⁻ dominant, with fresh to brackish salinity—189–3,680 mg/L total dissolved solids (TDS). Localised areas of Ca-SO₄²⁻ and Na-HCO₃⁻ dominant groundwater were impacted by industrial activities and legacy landfills, respectively. Stable isotopes (e.g. δ¹⁸O −5.7 to −2.9‰) and tritium activities (1.75–2.45 TU) within the aquifer indicate meteoric water recharged by modern rainfall with short residence times. Carbonate dissolution from shell material, and decay of organic waste and methanogenesis in landfill-leachate-impacted bores were shown to enrich δ¹³C values up to −4.2‰. In contrast, groundwater in the adjacent/lower aquitard was Na-Cl dominant and saline (19,600–23,900 mg/L TDS), with molar ratios reflective of ocean water, indicating relict emplaced salts. This is consistent with ¹⁴C dating of shell material, indicating deposition in a Holocene marine environment. The presence of tritium above background levels (0.20–0.35 TU) in the groundwater, however, suggests a component of modern recharge. Salinity fluctuations within the aquitard at times of peak river level suggest the modern water source is ingress from the adjacent Yarra River.]]> Wed 07 Feb 2024 16:39:57 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:44300 Tue 11 Oct 2022 16:05:32 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:50253 Tue 11 Jul 2023 16:29:13 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:50494 40% contribution) for three resident and five transient species, including polychaetes, blue swimmer crabs, toadfish, luderick, leatherjackets, oyster gobies, and stingarees. Benthic organic matter from the oyster reef was found to be a primary resource for 12 residents and four transient species, including crabs, shrimps, gastropods, and fish. Oyster reefs are key foraging grounds in the estuarine seascape, and their restoration will enhance fisheries productivity by broadening the trophic resource base and contribute to the estuarine energy transfer to higher trophic levels.]]> Thu 27 Jul 2023 10:15:39 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:37768 Sphyrna mokarran are the largest member of Sphyrnidae, yet the roles of these large sharks in the food webs of coastal ecosystems are still poorly understood. Here we obtained samples of muscle, liver and vertebrae from large S. mokarran (234–383 cm total length; L_T) caught as by‐catch off eastern Australia and used stable‐isotope analyses of δ¹⁵N, δ¹³C and δ³⁴S to infer their resource use and any associated ontogenetic patterns. The results indicated large S. mokarran are apex predators primarily relying on other sharks and rays for their diet, with a preference for benthic resources such as Australian cownose rays Rhinoperon neglecta during the austral summer. Teleosts, cephalopods and crustaceans were not significant components of S. mokarran diets, though some conspecifics appeared to rely on more diverse resources over the austral summer. Ontogenetic shifts in resource use were detected but trajectories of the increases in trophic level varied among individuals. Most S. mokarran had non‐linear trajectories in ontogenetic resource‐use shifts implying size was not the main explanatory factor. Stable isotope values of δ¹³C and δ³⁴S in muscle suggest S. mokarran span coastal, pelagic and benthic food webs in eastern Australia.]]> Thu 15 Apr 2021 10:37:54 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:52213 Thu 05 Oct 2023 10:23:35 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:49220 Sun 07 May 2023 09:37:55 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:9790 Sat 24 Mar 2018 08:11:04 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:9792 Sat 24 Mar 2018 08:11:03 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:18114 13C values are linked to low δ¹³C values of cave air and drip water during that time. This observation corresponds to times of reduced cave ventilation, high pCO₂ of cave air, low drip water pH, lower calcite supersaturation and typically high drip rates. In contrast, the translucent, dense laminae represent more or less complete lateral coalescence (inclusion-free) during the cold season (high calcite, drip water and cave air δ¹³C values), i.e. times of enhanced cave ventilation, low cave air pCO₂, increased drip water pH, relatively high calcite supersaturation and typically low drip rates. In essence, the relative development of the two lamina types reflects changes in the seasonality of external air temperature and precipitation, with a strong control of the winter air temperature on the intensity of cave-air exchange. Thick translucent, dense laminae are favoured by long, cold and wet winters and such conditions may be related closely to the North Atlantic Oscillation mode (weak westerlies) and enhanced Mediterranean cyclone activity during the cold season. Studies of speleothem lamination can thus help to better understand (and quantify) the role of seasonality changes, for example, during rapid climate events.]]> Sat 24 Mar 2018 08:04:36 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:17280 Sat 24 Mar 2018 08:01:49 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:19954 Sat 24 Mar 2018 07:58:33 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:5064 Sat 24 Mar 2018 07:48:53 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:48196 Sat 11 Mar 2023 12:30:29 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:50783 Sat 05 Aug 2023 11:08:33 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:52766 Mon 29 Jan 2024 18:40:13 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:50776 Mon 22 Apr 2024 11:47:11 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:55445 Fri 31 May 2024 14:28:24 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:37668 Dendronephthya australis, with its limited distribution along the central New South Wales (NSW) coastline, forms a habitat within the benthic estuarine environment that supports commercially significant and protected marine species. However, the functional role of the soft coral within this system is unknown. Organisms from primary producers through to secondary consumers were sampled from soft coral and sponge habitats inside the Port Stephens estuary, NSW, Australia in 2014. A food web model of the benthic habitat, created using stable isotopes of carbon and nitrogen, was used to describe the functional role of the soft coral in comparison to sponges, another important habitat for commercially significant and protected marine species. Primary consumers accessed a range of benthic and pelagic energy sources; however, secondary consumers were almost entirely dependent on pelagic energy sources. Soft coral and sponges accessed different primary sources for their energy requirements. There was no evidence that D. australis was used as a direct food source by consumers other than nudibranchs. In contrast, sponges were trophically linked with secondary consumers and are likely to play a direct role in pelagic energy transfer. Amphipods collected from the branches of D. australis were identified as major prey components in the diet of protected syngnathids, suggesting that while the soft coral functions as critical habitat, it is indirectly linked to higher trophic levels.]]> Fri 25 Jun 2021 13:34:15 AEST ]]>