Journal articles: 'Lower River Murray'

1

Rees, Gavin N., Gillian Beattie, Patricia M. Bowen, and Barry T. Hart. "Heterotrophic bacterial production in the lower Murray River, south-eastern Australia." Marine and Freshwater Research 56, no. 6 (2005): 835. http://dx.doi.org/10.1071/mf04232.

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Bacterial production is important in aquatic carbon cycles because it represents a key component whereby dissolved and particulate carbon can be recycled back into food webs. Despite its acknowledged importance, few studies have examined bacterial production in lowland rivers. Since studies have suggested bacterial production is closely related to some carbon pools, we anticipated this to be the case in the Murray River, but that the timing and type of carbon inputs in the Murray River may lead to bacterial dynamics that differ from studies from other sites. Bacterial abundance and production were measured at three contrasting sites of the lowland Murray River, south-eastern Australia, over an 18-month period. Bacterial abundance varied across the three sites on the Murray River and was correlated with chlorophyll a concentrations but not with temperature, nutrients, particulate organic carbon and dissolved organic carbon concentrations. Bacterial production also varied across the sites. Lowest production was at the site most immediately downstream of a large reservoir, with production generally ranging from 0.88 to 8.00 μg C L−1 h−1. Bacterial production in a reach within a large forest ranged from 4.00 to 17.38 μg C L−1 h−1. Production at the reach furthest downstream ranged from 1.04 to 23.50 μg C L−1 h−1. Bacterial production in the Murray River was generally greater than in the European River Spree, reaches of the Meuse and Rhine without immediate impacts from major urban centres and the Amazon River, but was similar to the concentration measured in the Mississippi and Hudson Rivers. Bacterial production was closely correlated with chlorophyll a concentration and total phosphorus, but not with temperature, dissolved organic carbon, particulate organic carbon or inorganic nitrogen. Despite the differences in production and respiration measured at different sites across the Murray River, bacterial growth efficiency was very similar at the three sites. Bacterial populations in the Murray River appear to be influenced by reach-specific conditions rather than broad-scale drivers such as temperature, carbon and nutrient concentrations.

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2

Maini, N., A. Buchan, and S. Joseph. "Derivation of a salinity target for the Lower Murray Darling Valley." Water Science and Technology 48, no. 7 (October 1, 2003): 105–12. http://dx.doi.org/10.2166/wst.2003.0430.

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The NSW Government commissioned catchment management boards (CMBs) to set the direction and process for catchment scale natural resource management. In the Lower Murray Darling, Rivers are highly regulated and water resources shared between three states. The Catchment Board only has jurisdiction over the northern bank of the Murray but salt and water enter the river from many locations upstream and along the area boundary. River salt and flow modelling has continually been improved to reflect and contribute to an increased understanding of salinity processes. The MDBC Salt Load study correlates 10 years of actual measured data with its modelled outputs, and estimates river salinities for 2020, 2050 and 2100. Routing models such as SALTFLO and MURKEY generate percentile salinity levels at different nodes in the River Murray downstream of the Lower Darling confluence. National, Murray-Darling Basin and NSW salinity management policy and legislative requirements were considered, MDBC model output was used to ensure the interim targets are achievable, auditable, and appropriate to the catchment. The method for an end-of-valley river based target for salinity is described. A target of less than 463 μS/cm for Lock 6, a point in the lower reaches of the Murray River is recommended for year 2010. Catchment management targets that express the main river salinity risk in five hydrologically distinct management zones are also recommended. Salinity management changes are needed in each zone to meet the end-of-valley target.

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3

Koehn, John D., and D. J. Harrington. "Collection and distribution of the early life stages of the Murray cod (Maccullochella peelii peelii) in a regulated river." Australian Journal of Zoology 53, no. 3 (2005): 137. http://dx.doi.org/10.1071/zo04086.

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The Murray cod (Maccullochella peelii peelii) is a large fish species keenly sought by anglers. However, this species has declined in distribution and abundance and is now listed nationally as vulnerable. This study was undertaken in the Ovens and Murray rivers, to collect larvae and age-0 Murray cod and determine the distribution of larval Murray cod around the mid-Murray River irrigation storage of Lake Mulwala. Murray cod larvae were collected from 17 of 18 sites: main channels and flowing anabranch channels of regulated and unregulated rivers, sites upstream and downstream of the lake, in the upper and lower reaches of the lake, and in the outflowing Yarrawonga irrigation channel. Larval Murray cod were collected only by methods that sampled drift in flowing waters. Age-0 Murray cod were collected by electrofishing in the main river, but not in off-channel waters, suggesting that cod are likely to settle into habitats in the main channel at a post-larval stage. The widespread occurrence of drifting larvae suggests that this species may be subject to previously unrecognised threats as they pass through hydro-electric power stations or become stranded in anabranch and irrigation channels. Results of this study are likely to be applicable to other species with drifting larval stages, and are relevant to other locations in the Murray–Darling Basin.

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4

Leigh, Sandra J., and Brenton P. Zampatti. "Movement and mortality of Murray cod, Maccullochella peelii, during overbank flows in the lower River Murray, Australia." Australian Journal of Zoology 61, no. 2 (2013): 160. http://dx.doi.org/10.1071/zo12124.

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Conservation of Murray cod (Maccullochella peelii), a large endangered fish species of Australia’s Murray–Darling Basin, relies on a detailed understanding of life history, including movement patterns and habitat use. We used radio-tracking to investigate the movement of 36 Murray cod in main channel and anabranch habitats of the lower River Murray during a flood and associated hypoxic blackwater event. During a flood peak of ~93 000 ML day–1, dissolved oxygen decreased to 1.2 mg L–1. Four movement types were observed: (1) localised small-scale movement, (2) broad-scale movement within anabranch habitats, (3) movement between anabranch and main channel habitats, and (4) large-scale riverine movement. Murray cod exhibited high fidelity to anabranch habitats but also moved extensively between anabranches and the main channel. Fish were consistently located in the main channel or permanent anabranches, suggesting that use of ephemeral floodplain habitats is limited, and highlighting the importance of connectivity between off-channel and main channel habitats. Mortality of radio-tagged fish was considerable (25%) in association with low dissolved oxygen concentrations, indicating that hypoxic blackwater may have had a substantial impact on Murray cod populations in the lower River Murray.

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5

Bormans, Myriam, Holger Maier, Michael Burch, and Peter Baker. "Temperature stratification in the lower River Murray, Australia: implication for cyanobacterial bloom development." Marine and Freshwater Research 48, no. 7 (1997): 647. http://dx.doi.org/10.1071/mf97058.

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The relationship between temperature stratification of the water column, river discharge and meteorological forcing was examined for the lower River Murray by using a combination of field measurements and a simple mixing criterion. Wind was found to be the dominant variable affecting the degree of temperature stratification under low flow conditions typical of summer. The results of a three-month intensive study were used in conjunction with six years of historical data to determine the stratification potential of the lower River Murray and its implication for water quality and cyanobacterial bloom development. The physical characteristics and therefore stratification behaviour of the water column in the river section studied are not conducive to sustained blooms at any time of the year because of a combination of strong winds and sufficiently high river discharges.

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6

Sheldon, Fran, and Keith F. Walker. "Spatial distribution of littoral invertebrates in the lower Murray - Darling River system, Australia." Marine and Freshwater Research 49, no. 2 (1998): 171. http://dx.doi.org/10.1071/mf96062.

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The abundance and richness of macroinvertebrates in the lower Murray and Darling rivers were examined at a macroscale (rivers), mesoscale (billabongs, backwaters, channel) and microscale (vegetation, snags, substrata). In the Darling, insects dominated (85% of taxa, 81% of individuals); the richest taxa were Diptera (26 taxa) and Coleoptera (15 taxa) and the most abundant were Hemiptera (47%) and Diptera (35%). In the Murray, insects again dominated (84% of taxa, 52% of individuals), particularly Diptera (22 taxa), Coleoptera (12 taxa) and Hemiptera (9 taxa), but there were more crustaceans (9% of taxa, 47% of individuals, particularly the atyid shrimp Paratya australiensis). Both assemblages were uneven: in the Darling, >50% of biomass was Micronecta spp. (Corixidae), Dicrotendipes sp. (Chironomidae) and Macrobrachium australiense (Palaemonidae); in the Murray, 70% of biomass was P. australiensis and Caridina mccullochi (Atyidae) and the insects Micronecta spp. (Corixidae) and Chironomus sp. (Chironomidae). Abundances generally were greatest in the Murray. Hydrologic and geomorphic factors influenced assemblages at the macroscale, whereas microhabitat diversity dominated at the mesoscale.

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7

L Groome, Roger. "At the End of the River: The Coorong and Lower Lakes." Pacific Conservation Biology 16, no. 4 (2010): 290. http://dx.doi.org/10.1071/pc110290.

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This is a marvelous text (29 cm X 23 cm, 247 pp) on the Coorong and other waters at the mouth of the Murray River in South Australia, their social and environmental values, and the problems which beset them. The Coorong itself is an unusual 110 kilometers long but narrow lagoon, running southeast along the coast from the Murray mouth. Authored principally by Associate Professor David Paton of the University of Adelaide, the text also contains vignettes by 22 other contributors. Its ten chapter are illustrated by 150 colour photographs (no less than 35 photographers contributed) and 35 are so delightful sketches. Almost 300 references are included, plus 50 tables and diagrams.

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8

Alaghmand, S., S. Beecham, and A. Hassanli. "Fully integrated physically-based numerical modelling of impacts of groundwater extraction on surface and irrigation-induced groundwater interactions: case study Lower River Murray, Australia." Natural Hazards and Earth System Sciences Discussions 1, no. 4 (July 26, 2013): 3577–624. http://dx.doi.org/10.5194/nhessd-1-3577-2013.

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Abstract. Combination of reduction in the frequency, duration and magnitude of natural floods, rising saline water-table in floodplains and excessive evapotranspiration have led to an irrigation-induced groundwater mound forced the naturally saline groundwater onto the floodplain in the Lower River Murray. It is during the attenuation phase of floods that these large salt accumulations are likely to be mobilised and will discharge into the river. The Independent Audit Group for Salinity highlighted this as the most significant risk in the Murray–Darling Basin. South Australian government and catchment management authorities have developed salt interception schemes (SIS). This is to pump the highly saline groundwater from the floodplain aquifer to evaporation basins in order to reduce the hydraulic gradient that drives the regional saline groundwater towards the River Murray. This paper investigates the interactions between a river (River Murray in South Australia) and a saline semi-arid floodplain (Clarks Floodplain) significantly influenced by groundwater lowering (Bookpurnong SIS). Results confirm that groundwater extraction maintain a lower water-table and more fresh river water flux to the saline floodplain aquifer. In term of salinity, this may lead to less amount of solute stored in the floodplain aquifer. This occurs through two mechanisms; extracting some of the solute mass from the system and changing the floodplain groundwater regime from a losing to gaining one. Finally, it is shown that groundwater extraction is able to remove some amount of solute stored in the unsaturated zone and mitigate the floodplain salinity risk.

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9

Berndt, R. M. "The Bark-canoe of the Lower River Murray, South Australia." Mankind 3, no. 1 (February 10, 2009): 17–28. http://dx.doi.org/10.1111/j.1835-9310.1941.tb00115.x.

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10

WILSON, CHRISTOPHER, STEWART FALLON, and TOM TREVORROW. "New radiocarbon ages for the Lower Murray River, South Australia." Archaeology in Oceania 47, no. 3 (October 2012): 157–60. http://dx.doi.org/10.1002/j.1834-4453.2012.tb00128.x.

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11

Kingsford, Richard T., Keith F. Walker, Rebecca E. Lester, William J. Young, Peter G. Fairweather, Jesmond Sammut, and Michael C. Geddes. "A Ramsar wetland in crisis - the Coorong, Lower Lakes and Murray Mouth, Australia." Marine and Freshwater Research 62, no. 3 (2011): 255. http://dx.doi.org/10.1071/mf09315.

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The state of global freshwater ecosystems is increasingly parlous with water resource development degrading high-conservation wetlands. Rehabilitation is challenging because necessary increases in environmental flows have concomitant social impacts, complicated because many rivers flow between jurisdictions or countries. Australia’s Murray–Darling Basin is a large river basin with such problems encapsulated in the crisis of its Ramsar-listed terminal wetland, the Coorong, Lower Lakes and Murray Mouth. Prolonged drought and upstream diversion of water dropped water levels in the Lakes below sea level (2009–2010), exposing hazardous acid sulfate soils. Salinities increased dramatically (e.g. South Lagoon of Coorong >200 g L–1, cf. modelled natural 80 g L–1), reducing populations of waterbirds, fish, macroinvertebrates and littoral plants. Calcareous masses of estuarine tubeworms (Ficopomatus enigmaticus) killed freshwater turtles (Chelidae) and other fauna. Management primarily focussed on treating symptoms (e.g. acidification), rather than reduced flows, at considerable expense (>AU$2 billion). We modelled a scenario that increased annual flows during low-flow periods from current levels up to one-third of what the natural flow would have been, potentially delivering substantial environmental benefits and avoiding future crises. Realisation of this outcome depends on increasing environmental flows and implementing sophisticated river management during dry periods, both highly contentious options.

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12

Twidale, C. R., and J. A. Bourne. "Course of the lower River Murray in South Australia: effects of underprinting and neotectonics?" Proceedings of the Royal Society of Victoria 121, no. 2 (2009): 207. http://dx.doi.org/10.1071/rs09207.

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The change in direction of the River Murray from westerly to southerly at North West Bend has been attributed to faulting or warping, but no appropriate structure has been located in the country rock coincident with the river course. Yet the angularity and the straightness of major sectors argue structural control. The plan course of the Murray downstream from Morgan is attributed to underprinting from basement fractures following the Middle Miocene but prior to the Late Pliocene. Uplift of the Marmon Jabuk structure superimposed on the effects of underprinting accounts for major departures from the SSW trend downstream from North West Bend, as well as the impounding of Lake Bungunnia. The upper shallow section of the valley-in-valley form was shaped at a time of higher baselevel in the Middle-Late Tertiary. The lower section is the present Gorge. The valley floor was lowered probably by subterranean solution and flow followed by collapse of the cavern roofs. Regression of the River at times of lower sea level caused the breach of the Marmon Jabuk blockage and the draining of Lake Bungunnia.

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13

Unmack, P. J., M. J. Young, B. Gruber, D. White, A. Kilian, X. Zhang, and A. Georges. "Phylogeography and species delimitation of Cherax destructor (Decapoda: Parastacidae) using genome-wide SNPs." Marine and Freshwater Research 70, no. 6 (2019): 857. http://dx.doi.org/10.1071/mf18347.

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Cherax is a genus of 58 species of decapod crustaceans that are widespread across Australia and New Guinea. We use single-nucleotide polymorphisms (SNPs) to examine phylogeographic patterns in the most widespread species of Cherax, namely, C. destructor, and test the distinctiveness of one undescribed species, two C. destructor subspecies, previously proposed evolutionarily significant units, and management units. Both the phylogenetic analyses and the analysis of fixed allelic differences between populations support the current species-level taxonomy of C. setosus, C. depressus, C. dispar and C. destructor, the distinctiveness of C. destructor albidus and C. d. destructor and the existence of one undescribed species. The two populations of C. d. albidus from the Glenelg and Wimmera rivers were significantly distinct, with eight diagnostic differences (<1% fixed differences, null expectation is four fixed differences), but this low level of divergence is interpreted as within the range that might be expected of management units, that is, among allopatric populations of a single species or subspecies. A southern clade of C. d. destructor comprising the Murray River and its tributaries upstream from its confluence with the Darling River is genetically distinct from a northern clade comprising populations from the Lake Eyre Basin, the northern half of the Murray–Darling Basin (Darling River catchment) and the Lower Murray River below the Darling confluence.

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14

Alaghmand, S., S. Beecham, and A. Hassanli. "Impacts of groundwater extraction on salinization risk in a semi-arid floodplain." Natural Hazards and Earth System Sciences 13, no. 12 (December 23, 2013): 3405–18. http://dx.doi.org/10.5194/nhess-13-3405-2013.

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Abstract. In the lower River Murray in Australia, a combination of a reduction in the frequency, duration and magnitude of natural floods, rising saline water tables in floodplains, and excessive evapotranspiration have led to an irrigation-induced groundwater mound forcing the naturally saline groundwater onto the floodplain. It is during the attenuation phase of floods that these large salt accumulations are likely to be mobilised and discharged into the river. This has been highlighted as the most significant risk in the Murray–Darling Basin and the South Australian Government and catchment management authorities have subsequently developed salt interception schemes (SIS). The aim of these schemes is to reduce the hydraulic gradient that drives the regional saline groundwater towards the River Murray. This paper investigates the interactions between a river (River Murray in South Australia) and a saline semi-arid floodplain (Clark's floodplain) that is significantly influenced by groundwater lowering due to a particular SIS. The results confirm that groundwater extraction maintains a lower water table and a higher amount of fresh river water flux to the saline floodplain aquifer. In terms of salinity, this may lead to less solute stored in the floodplain aquifer. This occurs through three mechanisms, namely extraction of the solute mass from the system, reducing the saline groundwater flux from the highland to the floodplain and changing the floodplain groundwater regime from a losing to a gaining one. It is shown that groundwater extraction is able to remove some of the solute stored in the unsaturated zone and this can mitigate the floodplain salinity risk. A conceptual model of the impact of groundwater extraction on floodplain salinization has been developed.

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15

Walker, K. F., and M. C. Thoms. "Environmental effects of flow regulation on the lower river Murray, Australia." Regulated Rivers: Research & Management 8, no. 1-2 (May 1993): 103–19. http://dx.doi.org/10.1002/rrr.3450080114.

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16

Whiterod, Nick R., and Keith F. Walker. "Will rising salinity in the Murray - Darling Basin affect common carp (Cyprinus carpio L.)?" Marine and Freshwater Research 57, no. 8 (2006): 817. http://dx.doi.org/10.1071/mf06021.

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Salinisation in the Murray–Darling Basin, Australia, may affect aquatic flora and fauna, including the common carp, an alien species that has become the most common fish in the river system. This study describes the responses of juvenile carp (31–108 mm total length) to salinity levels that prevail in some wetlands of the lower reaches of the River Murray. Carp are moderately tolerant of salinity (direct transfer LC50: 11 715 mg L–1), particularly after slow acclimation (LC50: 13 070 mg L–1), but sub-lethal effects are evident at lower salinities. These include effects on osmoregulation (>7500 mg L–1), behaviour (7500–12 500 mg L–1) and sperm motility in mature fish (150–300 mm) (8330 mg L–1). Salinities in some Murray–Darling Basin wetlands already approach half seawater (17 500 mg L–1) and carp populations in these important nursery areas could be impacted through sub-lethal effects on adults and lethal effects on juveniles, eggs and sperm.

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Kennedy, Shaun A., George G. Ganf, and Keith F. Walker. "Does salinity influence the distribution of exotic willows (Salix spp.) along the Lower River Murray?" Marine and Freshwater Research 54, no. 7 (2003): 825. http://dx.doi.org/10.1071/mf03035.

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The weeping willow Salix babylonica and crack willow S. fragilis dominate the riparian vegetation of the River Murray between Mannum and Wellington, South Australia, Australia. The presence of S. fragilis is confirmed, over-riding earlier, informal references to S. × rubens. In this region S. babylonica is represented by females and S. fragilis is represented by males. The flowering times of the two species overlap but the growing season begins earlier for the former. No evidence of hybridization was found, although this is not conclusive. Salix babylonica is most common upstream of Murray Bridge whereas S. fragilis occurs mainly downstream. A field survey in 1999 showed that estimated soil water conductivity varied between sites (median 6.0 mS cm–1) along the river, but this was not reflected in the distributions of the species. In a glasshouse experiment, cuttings of both species proved intolerant of conductivities exceeding 7 mS cm–1. In the field, foliar salt levels indicated that neither species was salt-stressed, despite growing in moderately saline soil. Also, it appears that the trees may access less saline river water in preference to that in the soil. The distributions of the two species in this region could reflect the history of planting rather than salinity tolerance.

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Mosley, Luke M., and Nigel Fleming. "Pollutant Loads Returned to the Lower Murray River from Flood-Irrigated Agriculture." Water, Air, & Soil Pollution 211, no. 1-4 (January 16, 2010): 475–87. http://dx.doi.org/10.1007/s11270-009-0316-1.

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19

Boulton, A. J., and L. N. Lloyd. "Macroinvertebrate assemblages in floodplain habitats of the lower river murray, South Australia." Regulated Rivers: Research & Management 6, no. 3 (July 1991): 183–201. http://dx.doi.org/10.1002/rrr.3450060304.

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20

Koehn, John D. "Using radio telemetry to evaluate the depths inhabited by Murray cod (Maccullochella peelii peelii)." Marine and Freshwater Research 60, no. 4 (2009): 317. http://dx.doi.org/10.1071/mf08163.

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Radio telemetry is widely used in studies of freshwater fishes, but the vertical position of fish in riverine environments is rarely reported. The present study tested the application of radio transmitters fitted with depth sensors to determine the vertical position of Murray cod in the lower Ovens River in south-eastern Australia. As the scale of depths in rivers is usually limited (<10 m in the present study), there is a greater need to assess measurement error. The study first involved trials to define depth measurement errors, and a mean relative bias of 9% (range 1.5–14.8%) towards greater depth was recorded. These data were then used to correct the depths recorded from tagged fish. Although data from this preliminary study are somewhat limited, results from the tagged fish showed that by day they all occupied the lower 15% of the water column, indicating that Murray cod exhibit demersal behaviour, using bottom rather than mid-water habitats. Although the present study highlights the importance of tag trials in determining errors, it also indicates the potential application of this technique to understanding the depth-integrated habitat preferences of Murray cod and other species.

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21

Gell, Peter A., Sorell Bulpin, Peter Wallbrink, Gary Hancock, and Sophie Bickford. "Tareena Billabong - a palaeolimnological history of an ever-changing wetland, Chowilla Floodplain, lower Murray - Darling Basin, Australia." Marine and Freshwater Research 56, no. 4 (2005): 441. http://dx.doi.org/10.1071/mf04107.

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A 427-cm sediment core was extracted from Tareena Billabong, a Murray River floodplain wetland in the extreme south-west of New South Wales, Australia. Analysis of fossil diatoms and pollen, sediment 210Pb and 137Cs profiles and radiocarbon and luminescence dating reveal that Tareena Billabong has undergone substantial environmental change in its ~5000-year history. Shortly after its formation, the billabong was a freshwater lagoon with a diatom flora dominated by Synedra ulna and Planothidium lanceolatum. An increase in Aulacoseira granulata, a river plankton dominant today, reflects two phases of increased connectivity with the Murray River in the mid to late Holocene. A shift to lagoonal taxa after ~3000 years BP is attributed to water balance and river-flow changes, possibly associated with regional climate change. Importantly, it appears to have undergone an extended phase of increasing turbidity, and possibly wetland salinity, commencing ~3000 years BP. Sedimentation increased at least 15-fold in the European phase. Billabong salinity increased markedly soon after European settlement, reaching a peak in the late 1800s AD. While regulation then increased the degree of connection between the billabong with the River in the 1920s AD, salinity levels remained high. Increased salinity is revealed by increases in the diatom taxa Amphora spp., Cyclotella meneghiniana, Gyrosigma acuminatum, Planothidium delicatulum and Tryblionella hungarica and by declines in Casuarinaceae, Eucalyptus, Myriophyllum and Cyperaceae pollen. Tareena Billabong was subjected to considerable environmental pressures from the early stages of European settlement in terms of sediment load, hydrological change and salinity.

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Doody, Tanya M., Simon N. Benger, Jodie L. Pritchard, and Ian C. Overton. "Ecological response of Eucalyptus camaldulensis (river red gum) to extended drought and flooding along the River Murray, South Australia (1997–2011) and implications for environmental flow management." Marine and Freshwater Research 65, no. 12 (2014): 1082. http://dx.doi.org/10.1071/mf13247.

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Riparian forest and woodlands of the lower River Murray floodplain are exhibiting deteriorating health as a result of anthropogenic alterations to flow regimes and south-eastern Australia’s long-term ‘Millennium Drought’ from 1997 to 2009. Extensive flooding in 2010/2011 brought the drought to an end, providing an opportunity to monitor ecological floodplain recovery. The relationship between flooding and lateral recharge and condition of the dominant riparian tree species, Eucalyptus camaldulensis, was determined between 2007 and 2011 using the Landsat (LTM5) Normalised Difference Vegetation Index (NDVI). Linking the river hydrograph with the River Murray Floodplain Inundation Model (RiM-FIM) allowed exploration of the relationship between inundation duration and E. camaldulensis water requirements. Results indicate lateral bank recharge is an important mechanism in the maintenance of vegetation condition along the River Murray channel. Higher in-channel irrigation water delivery during summer months was identified as critical to survival of trees adjacent to the channel during the drought. The research suggests that weir pool manipulation to create in-channel flood pulses will aid E. camaldulensis maintenance. Furthermore, release of environmental flows once every 3 to 5 years to create bank-full flow or preferably overbank flows, will increase hydrological connectivity between river banks, wetlands and riparian zones, providing positive ecological benefits to E. camaldulensis and other floodplain and aquatic ecological assets.

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Baker, Peter D. "Role of akinetes in the development of cyanobacterial populations in the lower Murray River, Australia." Marine and Freshwater Research 50, no. 3 (1999): 265. http://dx.doi.org/10.1071/mf98090.

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Planktonic populations and benthic resting stages (akinetes) of the common bloom-forming cyanobacteria Anabaena circinalis Rabenhorst and Anabaena flos-aquae f. flos-aquae (Lyngb.) Komárek were monitored in the Murray River near Nildottie and in adjacent floodplain wetlands (lagoons) from 1995 to 1997, to determine the extent of sporulation and the contribution of recruitment from the sediments to seasonal development of blooms. Physical and chemical characteristics of the water in the river and the lagoons were examined in relation to the succession of key life-cycle stages and growth. The warm, shallow lagoons supported considerably higher populations of Anabaena in the summer than did the river, with correspondingly higher incidence of sporulation. Viable akinetes were abundant in the sediments of both the river channel and the lagoons, providing a potentially significant inoculum for cyanobacterial growth. The apparent germination of akinetes early in summer and immediately following sporulation in mid summer indicated a strategy for both initiation and maintenance of populations. A. circinalis also persisted as a planktonic population throughout winter. Germination is considered more likely to occur in the shallow lagoons than in the main channel, principally because of frequent resuspension of sediments containing resting stages to the euphotic zone or because of direct penetration of light to the sediments.

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Clarke, Philip A. "The Ngarrindjeri nomenclature of birds in the Lower Murray River region, South Australia." Transactions of the Royal Society of South Australia 143, no. 1 (October 26, 2018): 118–46. http://dx.doi.org/10.1080/03721426.2018.1534530.

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Goss, Kevin F. "Environmental flows, river salinity and biodiversity conservation: managing trade-offs in the Murray - Darling basin." Australian Journal of Botany 51, no. 6 (2003): 619. http://dx.doi.org/10.1071/bt03003.

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The Murray–Darling basin's river system suffers from over-allocation of water resources to consumptive use and salinity threats to water quality. This paper draws attention to the current state of knowledge and the need for further investigations into the biological effect of river salinity on aquatic biota and ecosystems, the threats of dryland salinity to terrestrial biodiversity, and managing environmental flows and salinity control to limit the trade-offs in water-resource security and river salinity.There is growing evidence that river salt concentrations lower than the normally adopted threshold have sublethal effects on species and ecosystems, over a longer time period. Further knowledge is required.There is no agreed process for incorporating terrestrial biodiversity values at risk into a strategic response for dryland-salinity management. This is a public policy issue to be addressed.Recent studies have quantified the trade-off in surface water flow and river salinity from refforestation and revegetation of upland catchments to control salinity. The potential losses or benefits to environmental values have not been quantified.Such improved knowledge is important to the Murray–Darling basin and relevant to other river basins and catchments in Australia.

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Watson, F. T., R. J. Smernik, A. L. Doolette, and L. M. Mosley. "Phosphorus speciation and dynamics in river sediments, floodplain soils and leaf litter from the Lower Murray River region." Marine and Freshwater Research 70, no. 11 (2019): 1522. http://dx.doi.org/10.1071/mf18360.

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Phosphorus (P) availability, which depends on both P concentration and speciation, often controls primary productivity and algal-bloom formation in river systems. The river P pool is also connected to P pools of adjacent sediments, soils and vegetation. Thus, informed management of P in floodplain–river systems requires detailed understanding of P concentration and speciation in all of these interconnected components. We studied P speciation in river sediments and water, floodplain soils and river red gum (Eucalyptus camaldulensis) leaf litter from the Lower Murray region using conventional spectroscopic measurements, solution 31P nuclear magnetic resonance (31P NMR) spectroscopy, and leaching experiments to simulate floodplain re-wetting of leaf litter. Almost all (>85%) of the P in river sediments was in the orthophosphate form, whereas floodplain soils had higher proportions of organic P (PO) species. Both fresh and senescent river red gum leaf litter also had a much higher concentration of PO, primarily in the form of phytate. On submersion, there was a rapid (0–96h) loss of dissolved P from senescent leaves; release of dissolved organic carbon showed similar kinetics. Loss of P from the leaves included both organic and inorganic forms. The results have important implications for aquatic primary productivity and environmental management strategies.

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Bice, Christopher M., Matthew S. Gibbs, Nadine N. Kilsby, Martin Mallen-Cooper, and Brenton P. Zampatti. "Putting the “river” back into the Lower River Murray: quantifying the hydraulic impact of river regulation to guide ecological restoration." Transactions of the Royal Society of South Australia 141, no. 2 (July 3, 2017): 108–31. http://dx.doi.org/10.1080/03721426.2017.1374909.

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T. Kingsford, Richard. "Managing Australia's Scarce Water Resources for the Environment." Pacific Conservation Biology 15, no. 1 (2009): 4. http://dx.doi.org/10.1071/pc090004.

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Australia has 12 major drainage basins, but most water use and extraction comes from the Murray- Darling Basin, despite not having Australia?s more populous cities. About 66% of surface water use in Australia is extracted from the rivers of the Murray-Darling Basin (NLWRA 2001). The ecological impacts are widespread and insurmountable: key ecosystems are in various stages of collapse. Many of these are conservation reserves and wetlands recognized for their international importance under the Ramsar Convention. Populations of native fish species are considered to be only at 10% of pre European levels with 46% of the 35 fish species now listed as threatened at state level (MDBC 2004). Waterbird populations are also declining significantly, sometimes up to 80% over a period of about 25 years (Kingsford and Thomas 2004; Nebel et al. 2008). Many communities of floodplain vegetation are also in decline. The River Murray no longer breaks through the sand barriers to naturally flow out to sea, with flow now only maintained by a dredge (costing ~$100,000 per week) to ensure that sand does not completely block the Murray mouth. The lower lakes are below sea level for the first time in more than 7,000 years and marine incursions into this freshwater ecosystem have allowed colonies of marine worms Ficopomatus enigmaticus to build their calcareous colonies on the backs of freshwater turtles and crabs weighing them down.

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Finlayson, C. Max, Peter A. Gell, and John Conallin. "<i>Corrigendum to</i>: Continuing the discussion about ecological futures for the lower Murray River (Australia) in the Anthropocene." Marine and Freshwater Research 73, no. 10 (May 3, 2021): 1245. http://dx.doi.org/10.1071/mf20344_co.

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The lower Murray River (Australia) has been subject to considerable change from human activities, including the conversion of a variable flow system to one with regulated water levels and the conversion of the estuary to a freshwater system. These conditions will face further pressures owing to reduced flows and higher sea levels associated with climate change. Policy decisions to retain present target conditions could be reconsidered to improve habitat conditions for wetlands, native fish and waterbirds. Contrary to many views, this would be permissible under the Ramsar Convention and, by increasing the diversity of conditions, may assist managers to retain functional systems. This paper encourages a new conversation across the broader community to develop pathways to prepare for emerging pressures on the riverine ecosystems, and move into anthropogenic futures for the Lower Murray.

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30

Liang, C., M. B. Jaksa, Y. L. Kuo, and B. Ostendorf. "Identifying areas susceptible to high risk of riverbank collapse along the Lower River Murray." Computers and Geotechnics 69 (September 2015): 236–46. http://dx.doi.org/10.1016/j.compgeo.2015.05.019.

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31

Gell, Peter, John Tibby, Fiona Little, David Baldwin, and Gary Hancock. "The impact of regulation and salinisation on floodplain lakes: the lower River Murray, Australia." Hydrobiologia 591, no. 1 (October 2007): 135–46. http://dx.doi.org/10.1007/s10750-007-0806-3.

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Bower, Deborah S., Clare E. Death, and Arthur Georges. "Ecological and physiological impacts of salinisation on freshwater turtles of the lower Murray River." Wildlife Research 39, no. 8 (2012): 705. http://dx.doi.org/10.1071/wr11214.

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Context The increasing intensity and extent of anthropogenically mediated salinisation in freshwater systems has the potential to affect freshwater species through physiological and ecological processes. Determining responses to salinisation is critical to predicting impacts on fauna. Aims We aimed to quantify the response of wild-caught turtles from freshwater lakes that had become saline in the lower Murray River catchment. Methods Plasma electrolytes of all three species of freshwater turtle from South Australia were compared among two freshwater sites (Horseshoe Lagoon and Swan Reach), a brackish lake (Lake Bonney) and a saline lake (Lake Alexandrina). Key results Chelodina longicollis, C. expansa and Emydura macquarii from a brackish lake had higher concentrations of plasma sodium and chloride than those from freshwater habitats. However, osmolytes known to increase under severe osmotic stress (urea and uric acid) were not elevated in brackish sites. Turtles from the highly saline lake were colonised by an invasive marine worm which encased the carapace and inhibited limb movement. Conclusions Freshwater turtles in brackish backwaters had little response to salinity, whereas the C. longicollis in a saline lake had a significant physiological response caused by salt and further impacts from colonisation of marine worms. Implications Short periods of high salinity are unlikely to adversely affect freshwater turtles. However, secondary ecological processes, such as immobilisation from a marine worm may cause unexpected impacts on freshwater fauna.

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Wedderburn, Scotte D., Michael P. Hammer, Christopher M. Bice, Lance N. Lloyd, Nick S. Whiterod, and Brenton P. Zampatti. "Flow regulation simplifies a lowland fish assemblage in the Lower River Murray, South Australia." Transactions of the Royal Society of South Australia 141, no. 2 (July 3, 2017): 169–92. http://dx.doi.org/10.1080/03721426.2017.1373411.

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Nicol, Jason M., and George G. Ganf. "A botanical, ecological and hydrological contribution to understanding the Lower River Murray and beyond." Transactions of the Royal Society of South Australia 141, no. 2 (July 3, 2017): 92–107. http://dx.doi.org/10.1080/03721426.2017.1374818.

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Cann, John H., Robert P. Bourman, and Elizabeth J. Barnett. "Holocene Foraminifera as Indicators of Relative Estuarine-Lagoonal and Oceanic Influences in Estuarine Sediments of the River Murray, South Australia." Quaternary Research 53, no. 3 (May 2000): 378–91. http://dx.doi.org/10.1006/qres.2000.2129.

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AbstractIn southeastern South Australia, the River Murray debouches through a coastal barrier separating euryhaline estuarine-lagoonal waters from the Southern Ocean. Depending upon the relative freshwater outflow of the river and ingress of the ocean, water salinity varies greatly within the lower estuary. Ammonia beccarii and Elphidium articulatum are euryhaline species of foraminifera that characterize the estuary and back-barrier Coorong Lagoon. The inner-shelf marine environment hosts an assemblage in which Discorbis dimidiatus, E. crispum, E. macelliforme, and various cibicidid species predominate. In cored sediments recovered from the shallow lower estuary, the relative abundance of A. beccarii + E. articulatum was compared with that of D. dimidiatus + E. crispum + E. macelliforme + other species. These data, and AMS radiocarbon ages determined for foraminifera and ostracods, provide evidence of a change from maximum oceanic influence (5255 ± 60 yr B.P.) to maximum estuarine influence (3605 ± 70 yr B.P.). Over this same time interval, sea level fell relatively by about 2 m. However, the event was also contemporaneous with falling water levels in several Victorian lakes, and it is thus attributed to onset of climatic aridity. Reduced precipitation in the River Murray catchment and reduced freshwater outflow enhanced development of the flood-tide delta and constriction of the mouth.

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Mosley, Luke M., Freeman Cook, and Rob Fitzpatrick. "Field trial and modelling of different strategies for remediation of soil salinity and sodicity in the Lower Murray irrigation areas." Soil Research 55, no. 7 (2017): 670. http://dx.doi.org/10.1071/sr16272.

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Rising saline groundwatertables and drought in the Lower Murray Reclaimed Irrigation Area (LMRIA) has created soil salinity and sodicity conditions, which has resulted in a decline in agricultural production. A 2 month field experiment was conducted at Mobilong irrigation area using a randomised block design with trial plots (4m2) in each of the three blocks containing the following six treatments: (1) control (not irrigated), (2) irrigation (River Murray water) only, (3) gypsum application (1.5 kg/m2) and irrigation, (4) limestone application (1.5 kg/m2) and irrigation, (5) seawater (source of dissolved Ca2+) application (100mm depth) and irrigation and (6) acid (pH 3) drainage (to dissolve CaCO3 in soil to release Ca2+) application (100mm irrigation water depth) and irrigation. Soil electrical conductivity (EC), pH, exchangeable cations (Ca2+, Mg2+, Na+, K+), exchangeable sodium percentage (ESP) and saturated hydraulic conductivity were measured. The decrease in EC was greatest in the irrigation only treatment followed by the gypsum and limestone treatments. At the end of the trial, the EC in the irrigation only treatment was about one-quarter of the control, in which the EC increased. The seawater and acid drainage treatments reduced the soil EC relative to the control but the EC was 2–3dS/m higher than the irrigation, gypsum and limestone treatments at the end of the trial. The gypsum, irrigation only and limestone treatments approximately doubled the exchangeable Ca relative to the control and exchangeable Na was reduced. Unsaturated water and solute transport model (HYDRUS-UNSATCHEM) simulations were able to represent the general trends in the field results. The results suggest that only River Murray water irrigation and drainage could be effective for the management of soil salinity and sodicity in the LMRIA but further research is required to establish the threshold electrolyte concentration to prevent soil dispersion.

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Zampatti, Brenton P., and Sandra J. Leigh. "Within-channel flows promote spawning and recruitment of golden perch, Macquaria ambigua ambigua – implications for environmental flow management in the River Murray, Australia." Marine and Freshwater Research 64, no. 7 (2013): 618. http://dx.doi.org/10.1071/mf12321.

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Restoring fish populations in regulated rivers requires an understanding of relationships between hydrology and population dynamics. In the present study, spawning and recruitment of golden perch, Macquaria ambigua ambigua, were investigated in relation to flow in the regulated lower River Murray. All life stages were sampled in three successive years, with peak flows of 8500 (2004–05), 15 000 (2005–06) and 7000 ML day–1 (2006–07). Larvae occurred only in November/December 2005, and young-of-year fish only in early 2006. Counts of daily increments in otolith microstructure indicated spawning in late October/early November 2005. Back-calculated birth years for adults, derived from otoliths and compared with the hydrograph for the preceding 25 years, revealed the dominance of three year classes spawned in association with increased discharge in 2000, 1998 and 1996. In 2007, an additional year class of 1-year-old fish appeared, following spawning in 2005. In each case, strong recruitment followed spring–summer spawning, when peak flows were >14 000 ML day–1 and water temperatures would have exceeded 20°C. Restoration of within-channel flows of 15–25 000 ML day–1 from late spring through summer would promote spawning and recruitment and improve the resilience of golden perch populations in the lower Murray.

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Jensen, Anne, Clare Nicolson, and Jason Carter. "Preservation and Management of Natural Wetlands in the South Australian Murray Valley." Water Science and Technology 29, no. 4 (February 1, 1994): 325–33. http://dx.doi.org/10.2166/wst.1994.0217.

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The impact of river regulation has been to reduce flood frequencies on the Murray floodplain below Mildura. The lower frequency of inundation of wetlands reduces the number of successful breeding and regeneration events in floodplain biota, causing a decline in the health and vigour of many floodplain plants and animals. The potential for rehabilitation of floodplain wetlands through increased flushing flows has been demonstrated. The ultimate aim is to enhance habitat value and achieve maximum biodiversity. Future opportunities are identified for hydrological manipulation within river operating strategies to extend beneficial management on a floodplain scale to improve wetland habitat. These can be combined with rehabilitation techniques such as specific water allocations, grazing controls and physical works on individual wetlands to ensure preservation and sustainable management of natural wetlands along the South Australian Murray Valley. Results so far indicate that successful restoration of the wetlands will take a number of flushing events and will be dependent primarily on the acceleration and protection of natural regeneration processes.

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Lamontagne, S., W. S. Hicks, R. W. Fitzpatrick, and S. Rogers. "Sulfidic materials in dryland river wetlands." Marine and Freshwater Research 57, no. 8 (2006): 775. http://dx.doi.org/10.1071/mf06057.

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Due to a combination of river regulation, dryland salinity and irrigation return, lower River Murray floodplains (Australia) and associated wetlands are undergoing salinisation. It was hypothesised that salinisation would provide suitable conditions for the accumulation of sulfidic materials (soils and sediments enriched in sulfides, such as pyrite) in these wetlands. A survey of nine floodplain wetlands representing a salinity gradient from fresh to hypersaline determined that surface sediment sulfide concentrations varied from <0.05% to ~1%. Saline and permanently flooded wetlands tended to have greater sulfide concentrations than freshwater ones or those with more regular wetting–drying regimes. The acidification risk associated with the sulfidic materials was evaluated using field peroxide oxidations tests and laboratory measurements of net acid generation potential. Although sulfide concentration was elevated in many wetlands, the acidification risk was low because of elevated carbonate concentration (up to 30% as CaCO3) in the sediments. One exception was Bottle Bend Lagoon (New South Wales), which had acidified during a draw-down event in 2002 and was found to have both actual and potential acid sulfate soils at the time of the survey (2003). Potential acid sulfate soils also occurred locally in the hypersaline Loveday Disposal Basin. The other environmental risks associated with sulfidic materials could not be reliably evaluated because no guideline exists to assess them. These include the deoxygenation risk following sediment resuspension and the generation of foul odours during drying events. The remediation of wetland salinity in the Murray–Darling Basin will require that the risks associated with disturbing sulfidic materials during management actions be evaluated.

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Chambers, A. L., and J. Connor. "MODELLING THE COST OF IRRIGATOR RESPONSE TO SALINITY IN THE LOWER RIVER MURRAY, SOUTH AUSTRALIA." Acta Horticulturae, no. 792 (June 2008): 171–77. http://dx.doi.org/10.17660/actahortic.2008.792.18.

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41

Baker, Peter D., Justin D. Brookes, Michael D. Burch, Holger R. Maier, and George G. Ganf. "Advection, growth and nutrient status of phytoplankton populations in the lower River Murray, South Australia." Regulated Rivers: Research & Management 16, no. 4 (2000): 327–44. http://dx.doi.org/10.1002/1099-1646(200007/08)16:4<327::aid-rrr576>3.0.co;2-q.

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42

DISSPAIN, MORGAN C. F., CHRISTOPHER J. WILSON, and BRONWYN M. GILLANDERS. "Morphological and chemical analysis of archaeological fish otoliths from the Lower Murray River, South Australia." Archaeology in Oceania 47, no. 3 (October 2012): 141–50. http://dx.doi.org/10.1002/j.1834-4453.2012.tb00126.x.

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43

Hammer, Michael P., Christopher M. Bice, Arkellah Hall, Adrienne Frears, Adam Watt, Nick S. Whiterod, Luciano B. Beheregaray, James O. Harris, and Brenton P. Zampatti. "Freshwater fish conservation in the face of critical water shortages in the southern Murray–Darling Basin, Australia." Marine and Freshwater Research 64, no. 9 (2013): 807. http://dx.doi.org/10.1071/mf12258.

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The lower reaches of the expansive Murray–Darling Basin, Australia, are a hotspot for freshwater biodiversity. The regional ecosystem, however, has been significantly altered by river regulation, including local and catchment-wide water abstraction. Freshwater fishes have suffered from the resultant altered flow regime, together with other threats including habitat degradation and alien species. Impacts reached a critical point (imminent species extinction) during a prolonged drought (1997–2010) that lead to broad-scale habitat loss and drying of refuges during 2007–2010, and urgent conservation measures were subsequently instigated for five threatened small-bodied fish species. A critical response phase included ad hoc interventions that were later incorporated within a broader, coordinated multi-agency program (i.e. the Drought Action Plan and Critical Fish Habitat projects). On-ground actions included local translocation, alien species control, in situ habitat maintenance (e.g. earthworks, environmental water delivery), fish rescues, artificial refuge establishment and captive breeding. Improved river flows signalled an initial phase of recovery in 2011–2012 that included reintroductions. The present paper aims to document the actions undertaken in the Lower Murray, and review successes and lessons from practical examples that will help guide and inform management responses to conserve fish in modified systems subjected to severe water decline.

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Taylor, Ben, and George G. Ganf. "Comparative ecology of two co-occurring floodplain plants: the native Sporobolus mitchellii and the exotic Phyla canescens." Marine and Freshwater Research 56, no. 4 (2005): 431. http://dx.doi.org/10.1071/mf04196.

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In the northern Murray–Darling Basin (MDB), Australia, the displacement of native floodplain grasses by Phyla canescens (Lippia), an exotic herb, coincided with a reduced frequency of floodplain inundation owing to river regulation. Although river regulation and P. canescens occur in the southern MDB, P. canescens abundance has not increased significantly since 1988. This work reports on the current distribution of P. canescens and the native grass Sporobolus mitchellii on the lower River Murray. It demonstrates that there are significant differences in the edaphic characteristics of sites occupied by the two species and co-occurrence is rare. To explain this observation, two factors were investigated: the resilience of S. mitchellii to invasion by P. canescens and the response of both species to artificial spring floods. At initial densities of >25%, S. mitchellii exhibited strong resilience to invasion by P. canescens. The growth response of both species to spring floods was similar. However, P. canescens reproduced asexually when inundated and, on exposure, exhibited a root distribution that would enhance its capacity to survive future droughts. In contrast, S. mitchellii was more tolerant of low soil moisture than P. canescens. The re-introduction of spring floods could favour the expansion of P. canescens.

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45

Gell, Peter A. "Watching the tide roll away – contested interpretations of the nature of the Lower Lakes of the Murray Darling Basin." Pacific Conservation Biology 26, no. 2 (2020): 130. http://dx.doi.org/10.1071/pc18085.

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The Murray Darling Basin Plan (Murray Darling Basin Authority 2012) represents the largest investment by government in an Australian environmental management challenge and remains highly conflicted owing to the contested allocation of diminishing water resources. Central to the decision to reallocate consumptive water to environmental purposes in this Plan was the case made to maintain the freshwater character of two lakes at the terminus of the Murray Darling Basin, in South Australia. This freshwater state was identified as the natural condition on the basis of selected anecdotal evidence and was enshrined in the site’s listing under the Ramsar Convention. The commitment to the freshwater state was challenged under drought when sea water was seen as a means of averting acidification when low river flows risked the exposure of sulfidic sediments. Independent evidence from water quality indicators (diatoms) preserved in lake sediment records, however, attested to an estuarine, albeit variable, condition before the commissioning of near-mouth barrages in 1940. This interpretation for a naturally estuarine history, published after peer review, was overlooked in a report to the South Australian government, which argued, without the provision of new evidence from the lakes, that they were fresh for their entire history. This revised interpretation is widely cited in the scientific literature, government reports and online discussion and underpins a watering strategy aimed at a freshwater future for the Lower Lakes. The allocation of large volumes of fresh water to achieve this condition presents significant difficulties owing to the highly contested nature of water use across the Basin.

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Hammer, Michael P., Mark Adams, Peter J. Unmack, and Keith F. Walker. "A rethink on Retropinna: conservation implications of new taxa and significant genetic sub-structure in Australian smelts (Pisces:Retropinnidae)." Marine and Freshwater Research 58, no. 4 (2007): 327. http://dx.doi.org/10.1071/mf05258.

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The smelt genus Retropinna nominally includes three small (<150 mm) freshwater fish species endemic to south-eastern Australia and New Zealand. For the two Australian species, the broad range of R. semoni (Weber) on the mainland suggests some vulnerability to isolation and genetic divergence, whereas the apparent confinement of R. tasmanica McCulloch to Tasmania is curious if, as suspected, it is anadromous. Analyses of Australian material using allozyme electrophoresis show five genetically distinct species with contiguous ranges and no evidence of genetic exchange. Three occur along the eastern seaboard (including three instances of sympatry), another in coastal and inland south-eastern Australia and Tasmania, and a fifth species in the Lake Eyre Basin. There is no indication of a simple ‘tasmanica’ v. ‘semoni’ dichotomy, but instead a complex pattern involving discrete clusters for the Upper Murray plus Darling rivers, Lower Murray, Glenelg River and Tasmanian regions, with coastal western Victorian samples having varying affinity to these groups. The overall pattern is one of deep divergences among species and strong genetic sub-structuring within and provides a strong argument for extended studies to prepare for appropriate conservation measures.

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Zukowski, Sylvia, and Keith F. Walker. "Freshwater snails in competition: alien Physa acuta (Physidae) and native Glyptophysa gibbosa (Planorbidae) in the River Murray, South Australia." Marine and Freshwater Research 60, no. 10 (2009): 999. http://dx.doi.org/10.1071/mf08183.

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Physa acuta (Draparnaud), an invasive species from Europe, is the most abundant freshwater snail in the Lower River Murray. Its ascendancy follows a general decline of native species, including the morphologically and ecologically similar Glyptophysa gibbosa (Gould). We began with two hypotheses. The first required comparisons of the salinity and temperature tolerances and other attributes of eggs, juveniles and adults to reveal differences that might account for the relative abundances of the species. As anticipated, P. acuta proved to have higher fecundity, shorter hatching time and higher salinity and temperature tolerances than G. gibbosa. The second hypothesis concerned a possible competitive interaction between the species. This was confirmed, as when juveniles were kept together, under laboratory conditions, the growth rate of P. acuta increased and that of G. gibbosa decreased (with some mortality). We suggest that the apparent decline of G. gibbosa in the Lower Murray may reflect its sensitivity to salinity and its vulnerability in interactions with P. acuta. This is a global concern as P. acuta has spread also to North America, Japan and South Africa, and there have been reports of impacts on local species.

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Pate, F. Donald. "Bone chemistry and palaeodiet: Bioarchaeoiogical research at Roonka Flat, lower Murray River, South Australia 1983–1999." Australian Archaeology 50, no. 1 (January 2000): 67–74. http://dx.doi.org/10.1080/03122417.2000.11681667.

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Job, Thomas, Dan Penny, Bree Morgan, Quan Hua, Patricia Gadd, and Atun Zawadzki. "Multi-stage Holocene evolution of the River Murray Estuary, South Australia." Holocene 31, no. 1 (October 8, 2020): 50–65. http://dx.doi.org/10.1177/0959683620961487.

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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.

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Gell, Peter A. "Corrigendum to: Watching the tide roll away – contested interpretations of the nature of the Lower Lakes of the Murray Darling Basin." Pacific Conservation Biology 26, no. 2 (2020): 211. http://dx.doi.org/10.1071/pc18085_co.

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The Murray Darling Basin Plan (Murray Darling Basin Authority 2012) represents the largest investment by government in an Australian environmental management challenge and remains highly conflicted owing to the contested allocation of diminishing water resources. Central to the decision to reallocate consumptive water to environmental purposes in this Plan was the case made to maintain the freshwater character of two lakes at the terminus of the Murray Darling Basin, in South Australia. This freshwater state was identified as the natural condition on the basis of selected anecdotal evidence and was enshrined in the site's listing under the Ramsar Convention. The commitment to the freshwater state was challenged under drought when sea water was seen as a means of averting acidification when low river flows risked the exposure of sulfidic sediments. Independent evidence from water quality indicators (diatoms) preserved in lake sediment records, however, attested to an estuarine, albeit variable, condition before the commissioning of near-mouth barrages in 1940. This interpretation for a naturally estuarine history, published after peer review, was overlooked in a report to the South Australian government, which argued, without the provision of new evidence from the lakes, that they were fresh for their entire history. This revised interpretation is widely cited in the scientific literature, government reports and online discussion and underpins a watering strategy aimed at a freshwater future for the Lower Lakes. The allocation of large volumes of fresh water to achieve this condition presents significant difficulties owing to the highly contested nature of water use across the Basin.

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Journal articles on the topic 'Lower River Murray'

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