Salinity-induced acidification in a wetland sediment through the displacement of clay-bound iron(II)

2010 ◽  
Vol 7 (5) ◽  
pp. 413 ◽  
Author(s):  
Annaleise R. Klein ◽  
Darren S. Baldwin ◽  
Balwant Singh ◽  
Ewen J. Silvester
Keyword(s):  
Alternative Pathway ◽  
Natural Sediment ◽  
Inland Waterways ◽  
Proton Production ◽  
Murray River ◽  
Eastern Australia ◽  
Displacement Experiments ◽  
Low Sulfur ◽  
Hydrolysis Of ◽  
Sulfur Containing

Environmental context Acidification of inland waterways is an emerging issue worldwide, mostly because it disturbs the balance of reduced sulfur species in soils, sediments and mine tailings. We describe a pathway for wetland acidification through salt displacement and oxidation of Fe2+ from clay minerals. This alternative pathway for acidification raises environmental concerns because an increasing number of inland waterways are affected by increasing salinity. Abstract A wetland near the Murray River (south-eastern Australia) was found to have significant levels of exchangeable reduced iron (Fe2+) in the sediment clay-zone, and the potential for acidification under high salinity and oxidising conditions. Cation exchange experiments using purified clay from this site show relative affinities consistent with the lyotrophic series: Fe2+>Ca2+>Mg2+>H+>K+>Na+. This relative affinity is confirmed in Fe2+ displacement experiments using natural sediment clay. Proton production during oxidation of salt-treated sediments corresponds to that expected for the oxidation and hydrolysis of Fe2+ displaced from clay interlayers, taking into account the buffering properties of the sediment matrix. This work shows that wetland acidification can occur in low sulfur-containing wetlands and is not exclusively a problem associated with sulfidic sediments.

scholarly journals Studies on the sulfur-containing chelating agents. XLVI. Hydrolysis of thio-.BETA.-diketones and related amides in acetonitrile-water mixture.

1977 ◽  
Vol 25 (1) ◽  
pp. 158-162 ◽  
Author(s):  
SHIGENORI HARADA ◽  
MINORU SAWADA ◽  
MASAHIKO CHIKUMA ◽  
AKIRA YOKOYAMA ◽  
HISASHI TANAKA
Keyword(s):  
Chelating Agents ◽  
Water Mixture ◽  
Hydrolysis Of ◽  
Sulfur Containing

scholarly journals The effect of water level on lateral movements of fish between river and off-channel habitats and implications for management

2010 ◽  
Vol 61 (3) ◽  
pp. 271 ◽  
Author(s):  
Jarod Lyon ◽  
Ivor Stuart ◽  
David Ramsey ◽  
Justin O'Mahony
Keyword(s):  
Water Level ◽  
Fish Community ◽  
Life History Strategy ◽  
Water Levels ◽  
Water Level Fluctuations ◽  
Main River Channel ◽  
Murray River ◽  
Wetland Biodiversity ◽  
Eastern Australia ◽  
Riverine Wetland

Off-channel habitats, such as wetlands and backwaters, are important for the productivity of river systems and for many species of native fish. This study aimed to investigate the fish community, timing and cues that stimulated movement to and from off-channel habitats in the highly regulated Lake Hume to Lake Mulwala reach of the Murray River, south-eastern Australia. In 2004–05, 193 712 fish were collected moving bi-directionally between a 50-km section of the Murray River and several off-channel habitats. Lateral fish movements approximated water level fluctuations. Generally as water levels rose, fish left the main river channel and moved into newly flooded off-channel habitats; there was bi-directional movement as water levels peaked; on falling levels fish moved back to the permanent riverine habitats. Fish previously classified as ‘wetland specialists’, such as carp gudgeons (Hypseleotris spp.), have a more flexible movement and life-history strategy including riverine habitation. The high degree of lateral movement indicates the importance of habitat connectivity for the small-bodied fish community. Wetlands adjacent to the Murray River are becoming increasingly regulated by small weirs and ensuring lateral fish movement will be important in maintaining riverine-wetland biodiversity.

Chemistry of pyrrolic compounds. XLVIII. The chemistry of porphyrins carrying sulfur-containing substituents at a meso-carbon

1981 ◽  
Vol 34 (12) ◽  
pp. 2595 ◽  
Author(s):  
PS Clezy ◽  
CJR Fookes ◽  
GA Smythe
Keyword(s):  
Hydrolysis Of ◽  
Sulfur Containing ◽  
Ring Synthesis

The preparation of a meso-thioacetoxyporphyrin by ring synthesis from a dipyrrylthione is described together with the reaction of thiocyanogen with octaethylporphyrin and coproporphyrin 11 to give meso-thiocyanatoporphyrins. Attempts to produce meso-mercaptoporphyrins by hydrolysis of either meso-thioacetoxy- or meso-thiocyanato-porphyrins failed. Instead the corresponding disulfides were produced and the properties of this latter group are described.

Too close for comfort: a fishway exit and a hydro-power station inlet

2010 ◽  
Vol 61 (1) ◽  
pp. 23 ◽  
Author(s):  
Ivor G. Stuart ◽  
John D. Koehn ◽  
Tim A. O'Brien ◽  
John A. McKenzie ◽  
Gerry P. Quinn
Keyword(s):  
Management Strategies ◽  
Field Testing ◽  
High Water ◽  
Fish Passage ◽  
Native Fish ◽  
Power Station ◽  
Hydro Power ◽  
Murray River ◽  
Eastern Australia ◽  
Radio Transmitters

A major environmental issue for hydro-electric power generation is passage of fish through turbines, or entrainment onto trash racks. At Yarrawonga Weir, on the upper Murray River in south-eastern Australia, the positioning of a fish lock resulted in the potential for upstream migrating fish to be swept back into the adjacent power station by cross flows. In 2004, a 4.5-m long steel extension flume was attached to the exit to alleviate this problem. To determine the fate of native fish after exiting the extension flume, 72 individuals (305–1015 mm long) were implanted with radio-transmitters and released into the fish lock exit channel. In 2004 (power station inflows 10 300 ML day–1), the majority of fish exited successfully (44 of 45) and only a single fish (2%) was entrained into the power station. In 2005 (power station inflows 12 000 ML day–1), fish again exited successfully (26 of 27) but with a higher proportion entrained (5 of 27; 18%). This reduced success appeared to be related to strong transverse flows with high water velocities adjacent to the fish lock exit. The efficiency of fish passage at this site might be improved by altering water management strategies, integrating engineering and fish biology, and through field-testing of proposed solutions.

Spatial partitioning in the use of structural woody habitat supports the cohabitation of two cod species in a large lowland river

2016 ◽  
Vol 67 (12) ◽  
pp. 1835 ◽  
Author(s):  
J. A. Lieschke ◽  
J. P. Lyon ◽  
P. D. Moloney ◽  
S. J. Nicol
Keyword(s):  
Lowland River ◽  
Specific Interactions ◽  
Negative Consequences ◽  
Catch Per Unit Effort ◽  
Spatial Partitioning ◽  
Murray River ◽  
Eastern Australia ◽  
The Common ◽  
Species Specific ◽  
Murray Cod

Many freshwater fish worldwide have been shown to use Structural Woody Habitat (SWH) for a variety of reasons. The mid reaches of the Murray River, a large lowland river in south-eastern Australia, was surveyed by boat electrofishing, to investigate the use of SWH type (hollows, rootmass and solids), SWH distance to bank (near bank, intermediate to bank and mid-channel) and the interaction between SWH type and distance to bank. The study found that Murray cod catch per unit effort (CPUE) increased in near-bank areas when hollows were a component of the SWH. The CPUE of trout cod was higher when hollows were present. However, the interactions between distance to bank and hollow SWH were complex and dependent on presence or absence of rootmass. The species-specific interactions between SWH microhabitat and distance to bank found within this study has important relevance for stream managers. The common practice of realigning SWH favours Murray cod over trout cod, which could have negative consequences for the endangered trout cod. More broadly, managers may need to consider a balance of SWH type and where it is placed in the river for the species they are targeting when rehabilitating rivers via the introduction of SWH.

A theory of prior streams as a casual factor of soil occurrence in the riverine plain of South-Eastern Australia

1950 ◽  
Vol 1 (3) ◽  
pp. 231 ◽  
Author(s):  
BW Butler
Keyword(s):  
Land Surface ◽  
Alluvial Fan ◽  
South Eastern ◽  
South Wales ◽  
Local Soil ◽  
Murray River ◽  
Eastern Australia ◽  
Soil Surveys ◽  
South Eastern Australia

A new theory is submitted on the origin of the soil formations in the alluvial plains region of southern New South Wales and Victoria embracing the Murray River and tributaries which has been given the name of the Riverine Plain of South-Eastern Australia. The Riverine Plain is delineated and the climate and physiography of the environment are briefly described. The theory postulates the occurrence of a system of prior streams independent of the present stream pattern; from the activity of this system the present soils and land surface were derived. The formations are discussed in terms of sedimentary array, salinity, and degree of leaching. Figures illustrate the ideal sediment pattern of a prior stream formation, a typical alluvial fan, and a simplified map of the region showing prior and present stream systems. A classification of the named soils from local soil surveys is given in the form of 15 sequences of general catenary relationship. The influence of halomorphism in soil development is discussed with the deduction that solonetzous and solodous soils occur generally throughout the region. The age of prior stream activity is set at late Pleistocene to early Recent.

Temporal variability in fish assemblage structure and recruitment in a freshwater-deprived estuary: The Coorong, Australia

2010 ◽  
Vol 61 (11) ◽  
pp. 1298 ◽  
Author(s):  
Brenton P. Zampatti ◽  
Christopher M. Bice ◽  
Paul R. Jennings
Keyword(s):  
Fish Assemblage ◽  
Fish Assemblages ◽  
Marine Species ◽  
River Regulation ◽  
Assemblage Structure ◽  
Estuarine Fish ◽  
Fish Assemblage Structure ◽  
Murray River ◽  
Eastern Australia ◽  
Freshwater Inflows

River regulation can diminish freshwater flows to estuaries and compromise estuarine functionality. Understanding biotic responses to altered flow regimes is imperative to effectively manage aquatic ecosystems. The present study investigated temporal variation in fish assemblage structure and the recruitment of catadromous fish in the Coorong estuary at the terminus of the Murray River, in south-eastern Australia. Over the three-year study period, freshwater inflows to the estuary diminished and ultimately ceased, disconnecting freshwater and estuarine environments. It was hypothesised that these conditions would lead to (1) increases in estuarine salinities and concomitant changes in fish assemblage structure and abundance, and (2) decreased recruitment of catadromous fish. As freshwater inflow decreased, salinities immediately downstream of a series of tidal barrages increased from brackish to marine–hypersaline, species richness and diversity decreased, freshwater and diadromous species became less abundant and assemblages were increasingly characterised by marine species. Furthermore, the abundance of young-of-year catadromous fish decreased dramatically. Excessive regulation of freshwater inflows is resulting in the Coorong estuary resembling a marine embayment, leading to a loss in species diversity. We suggest, however, that even small volumes of freshwater may promote diversity in estuarine fish assemblages and some recruitment of catadromous species.

Aggregates of particulate matter and aufwuchs on Elodea canadensis in irrigation waters, and inactivation of diquat

1982 ◽  
Vol 33 (3) ◽  
pp. 589 ◽  
Author(s):  
KH Browner
Keyword(s):  
Particulate Matter ◽  
Elodea Canadensis ◽  
Inland Waters ◽  
Surface Complex ◽  
South Eastern ◽  
Murray River ◽  
Eastern Australia ◽  
Aquatic Herbicides ◽  
High Concentrations ◽  
Irrigation Waters

In irrigation waters from the Murrumbidgee River and Murray River, south-eastern Australia. shoots of E. canadensis are heavily encrusted with a loosely attached complex of inorganic colloids with aufwuchs. Although 9,10-dihydro-8a,10a-diazoniaphenanthrene ion (diquat) is widely used overseas for the management of submerged weeds. it is often ineffective in Australian inland waters. Although several factors may be involved, measurements have shown that this surface complex would inactivate relatively high concentrations of diquat by adsorption. The activity of other aquatic herbicides may also be impaired.

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