Academic literature on the topic 'Molonglo River'

Seeps and previously deposited particulate material from mine workings at Captains Flat are still major sources of metal contamination in the Molonglo River. The impact of metal contamination as it entered the river is shown by the lower variety and numbers of animal taxa collected at downstream sites compared with upstream areas. Comparison with studies conducted before the remedial works shows that there has been little or no discernible change to the chemical or biological condition of the river during periods of low flow.

Incidental captures of platypuses have been recorded during fisheries research programs conducted in the Australian Capital Territory over the past 25 years. Ad hoc records have also been recorded from Australian Capital Territory Parks and Conservation Service staff and members of the public as part of an ongoing database project known as the ACT Vertebrate Atlas. Information is presented on the distribution and relative abundance of platypuses in the major ACT streams. There appear to have been some localised declines in a number of ACT platypus populations in the Murrumbidgee, Molonglo and Queanbeyan River systems. Possible reasons behind these declines are discussed.

A comprehensive sediment sampling program was undertaken in the upper Molonglo catchment in south-eastern New South Wales to determine if mineral magnetics could be used to estimate sidestream contribution at river confluences in this environment. Some 12 confluences were examined over 1400 km 2 in 2 major basins and over 2 contrasting geological types. Sediment samples were divided into 7 size classes and the following magnetic properties measured: magnetic susceptibility at 2 frequencies, isothermal remanent magnetisation at 3 flux densities, and anhysteristic remanent magnetisation. The sidestream inputs were calculated for each particle size class from the range of magnetic parameters. Significant discrepancies and differences appeared in the resultant sidestream inputs, and this paper outlines the conclusions as to the reliability of the different analytical procedures. It is shown that both the concentration and magnetic grain size of ferrimagnetic minerals in the sediments must be taken into account. Where the difference in magnetic grain size between the upstream and sidestream sediments is small, the use of parameter crossplots or bulked magnetic ratios is generally not appropriate. The use of mass (concentration) magnetic values may be better. The difference in the demands of the crossplots and mass values methods is that crossplots require a wide range of mass magnetic concentrations in each branch, with the upstream and sidestream sediments having different magnetic grain sizes, whereas the mass values procedure does best with a very limited (but different) range of concentrations at the upstream and sidestream branches, but similar magnetic grain sizes. This paper provides an extensive discussion of the estimation technique using different parameter combinations, and uses 3 contrasting confluences as case studies.

Mercury (Hg) contamination is an environmental concern as a by-product of legacy mining in Australia. Here we investigate the spatial and temporal distribution of Hg in the Molonglo River system in New South Wales, Australia, and assess the physical and chemical factors influencing that distribution. Mercury concentrations in sediment cores were measured in conjunction with 210Pb and 137Cs dating to establish historical contamination. This was done at the source mine site of Captains Flat, New South Wales, and the system’s sink in Lake Burley Griffin, Australian Capital Territory. Additionally, surficial sediment Hg concentrations along the Molonglo River were analyzed to determine the spatial distribution of Hg. Analytical results showed the primary physical and chemical factors influencing Hg dispersion to be distance, total organic matter, and the presence of iron oxides and oxyhydroxides. The highest Hg concentrations were near the mine site at Captains Flat and decreased significantly with distance. Sediment core analyses in both Captains Flat and the lake showed reductions in Hg concentrations toward surficial sediment layers. It is suggested government-funded rehabilitation programs are playing a part in reducing the release of metal contamination.

Abstract Few taxa exhibit the variability of sex-determining modes as amphibians. However, due to the presence of homomorphic sex chromosomes in many species, this phenomenon has been difficult to study. The Australian frog, Litoria aurea, has been relatively well studied over the past 20 years due to widespread declines largely attributable to chytrid fungus. However, it has been subject to few molecular studies and its mode of sex determination remained unknown. We applied DArTseq™ to develop sex-linked single nucleotide polymorphisms (SNPs) and restriction fragment presence/absence (PA) markers in 44 phenotypically sexed L. aurea individuals from the Molonglo River in NSW, Australia. We conclusively identified a male heterogametic (XX-XY) sex determination mode in this species, identifying 11 perfectly sex-linked SNP and six strongly sex-linked PA markers. We identified a further 47 moderately sex-linked SNP loci, likely serving as evidence indicative of XY recombination. Furthermore, within these 47 loci, a group of nine males were found to have a feminised Y chromosome that significantly differed to all other males. We postulate ancestral sex-reversal as a means for the evolution of this now pseudoautosomal region on the Y chromosome. Our findings present new evidence for the ‘fountain of youth’ hypothesis for the retention of homomorphic sex chromosomes in amphibians and describe a novel approach for the study of sex chromosome evolution in amphibia.

The Australian Constitution of 1901 required Parliament to establish its seat of Government in territory in New South Wales, but distant from Sydney. Interpreted as cause for building a new city it was, from the earliest deliberations, conceived as a city beautified by landscape and enhanced by water. Despite Australia's variable climate, particularly it's unreliable rainfall, the Canberra site on the Molonglo River provided an opportunity for storing a large body of ornamental water in a picturesque landscape setting, provided storage reservoirs were built to maintain water levels. Walter Burley Griffin's design gave the Lake form as a chain of ornamental lakes and parklands through the centre of the city. However, developing the Lake was complex and costly and although Parliament met at Canberra from 1927 it was not until the early 1960s that work began on implementing the Lake. Lake Burley Griffin was inaugurated in 1964. Inquiring into the significance of landscape setting and ornamental water for Australia's National capital the thesis reviews designed landscapes in cities that Australia aspired to emulate and the role of the professions in these designs. Using Canberra's lake as a focus this thesis examines the national and international context of landscape ideas, analyses the processes of landscape implementation in the public domain and evaluates the design outcome. The thesis also highlights the role of national aspiration, the rivalry between Federal and State governments, the power of government bureaucracy, the influence of the design professions and the ascendancy of Modernism as a design force in the built environment. The thesis establishes that over the sixty-year period Australian perceptions and expectations of landscape underwent a fundamental change. From the idea of landscape as a part of the aesthetic and moral high ground of national consciousness and international discourse, landscape, particularly landscape with water, became a device to consolidate power, bolster national pride, garner international recognition and enhance recreational opportunity. The thesis establishes the fundamental importance of the Lake landscape in creating a distinctive image of a visually unified National capital as well as a public place for people. As an empirical thematic history the thesis articulates landscape ideas and practice with the creation of a place of national significance. Through links with cultural context, the history of cities, and the history of design the research and its findings extend the knowledge base of the profession and practice of landscape architecture in Australia.