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1
Jasonsmith, J. F., W. Maher, A. C. Roach e F. Krikowa. "Selenium bioaccumulation and biomagnification in Lake Wallace, New South Wales, Australia". Marine and Freshwater Research 59, n. 12 (2008): 1048. http://dx.doi.org/10.1071/mf08197.
Testo completoAbstract (sommario):
Selenium concentrations were measured in water, sediments and organisms inhabiting a freshwater coal power station cooling reservoir. Se concentrations found were: water, 1.9 ± 2 μg L–1; sediment, 7 ± 1 μg g–1; phytoplankton, 3.4 μg g–1; zooplankton, 5.3 μg g–1; epiphytic algae, 1.3 ± 0.2 μg g–1; benthic algae, 8 ± 2 μg g–1; macrophyte leaves, 2.7–2.8 μg g–1; macrophyte roots, 0.5–6.5 μg g–1; detritus, 10 μg g–1; Oligochaeta, 11 μg g–1; Corbiculidae, 1.1 μg g–1; Insects, 3.7–8.3 μg g–1; Gastropoda, 3.2 μg g–1; Crustacea, 3.1–6 μg g–1; whole fish, 2.2–13 μg g–1; and fish liver, 134–314 μg g–1. Bioconcentration factors were similar to those found in aquatic ecosystems with comparable Se concentrations in the water column. A food web was constructed with four main food chains (phytoplankton, epiphytic algae, benthic algae and sediment/detrital), with fish fed from multiple pathways. Biomagnification only occurs along food chains for flathead gudgeons and rainbow trout. Se concentrations in food sources were above the 3 μg g–1 dietary Se level considered to induce teratogenesis in fish spawning. Flathead gudgeons were found to be suffering teratogenesis and rainbow trout showed no evidence of teratogenesis.
2
Webster, Ian T., e Graham P. Harris. "Anthropogenic impacts on the ecosystems of coastal lagoons: modelling fundamental biogeochemical processes and management implications". Marine and Freshwater Research 55, n. 1 (2004): 67. http://dx.doi.org/10.1071/mf03068.
Testo completoAbstract (sommario):
This paper presents a biogeochemical model of a coastal lagoon intended to be representative of lagoons occurring along the south-east and south-west coasts of Australia. Many of these lagoons are threatened by increased nutrient loads because of land use change, by alterations to their freshwater inflows and by modification to their tidal flushing regimens. The model simulates the biogeochemical response of the lagoon to nutrient (nitrogen) loading and includes nutrient transformation processes in the sediments, as well as in the water column. The paper focuses on the response of primary producers to increasing and decreasing nutrient loads and how the response is altered by changes in the flushing rate of the lagoon with the sea. In common with lakes, the modelled lagoon exhibits alternative stable states representing macrophyte or phytoplankton dominance depending on nutrient loading and history. A third state representing severe degradation occurs when denitrification shuts down. A characteristic of Australian coastal lagoon systems is that, due to highly sporadic rainfall patterns, nutrient inflows are dominated by intermittent extreme events. The modelling demonstrates that such a loading regimen may be expected to generally increase the vulnerability of the lagoon to increasing nutrient loads. The results of the analysis presented are pertinent to several questions raised by coastal managers, such as what are the expected benefits of improving flushing by dredging and what are the consequences of altering the timing and magnitudes of the loads reaching the lagoons?
3
Hawkins, PR, LE Taplin, LJ Duivenvoorden e F. Scott. "Limnology of oligotrophic dune lakes at Cape Flattery, North Queensland". Marine and Freshwater Research 39, n. 4 (1988): 535. http://dx.doi.org/10.1071/mf9880535.
Testo completoAbstract (sommario):
Physical, chemical and biotic attributes of 16 lakes and ponds in the siliceous dunefields of Cape Flattery, in the humid tropics of Australia, have been investigated. The dune lakes are similar to those of dunefields in south-eastern Queensland, with very low to low conductivity (62-338 �S cm-1), low pH (3.9-6.8), and low to high humic content (gilvin 0.0-31.0 g440 m-1). These lakes are apparently not perched above the local water table. The ionic compositions of all lakes were very similar, with NaCl predominating and with very low concentrations of Mg, Ca, K, and SO4. Bicarbonate was absent or negligible in most lakes. The oligotrophic lakes are characterized by a desmid-diatom limnetic plankton of moderate diversity (12-35 species per lake). Of 144 taxa of phytoplankton recognized, 58% were desmids and 15% diatoms. The zooplankton was of low diversity and dominated by Calamoecia ultima. Twenty-nine species of aquatic macrophytes and 11 species of fish were recorded. Freshwater turtles (possibly Chelodina rugosa Ogilby), and the estuarine crocodile, Crocodylus porosus Schneider, were recorded from some lakes. Principal component analysis of chemical data distinguished three groups of lakes: a series of humic-stained ponds and lakes, a group of clear-water lakes with little or no humic staining, and a former barrier lagoon. Cluster analysis of the phytoplankton flora consistently segregated the clear-water lakes from humic-stained lakes but, in general, concordance of chemical, physiographic and biotic characteristics was poor. Existing classification schemes for Australian dune lakes, based on similar sets of physiographic, chemical and biotic data, do not cater well for the Cape Flattery lakes. A more useful classification may derive from consideration of the hydrological processes influencing their water balance and chemical characteristics.
4
Davis, Jenny A., Megan McGuire, Stuart A. Halse, David Hamilton, Pierre Horwitz, Arthur J. McComb, Ray H. Froend, Michael Lyons e Lien Sim. "What happens when you add salt: predicting impacts of secondary salinisation on shallow aquatic ecosystems by using an alternative-states model". Australian Journal of Botany 51, n. 6 (2003): 715. http://dx.doi.org/10.1071/bt02117.
Testo completoAbstract (sommario):
Alternative-states theory commonly applied, for aquatic systems, to shallow lakes that may be dominated alternately by macrophytes and phytoplankton, under clear-water and enriched conditions, respectively, has been used in this study as a basis to define different states that may occur with changes in wetland salinity. Many wetlands of the south-west of Western Australia are threatened by rapidly increasing levels of salinity as well as greater water depths and permanency of water regime. We identified contrasting aquatic vegetation states that were closely associated with different salinities. Salinisation results in the loss of freshwater species of submerged macrophytes and the dominance of a small number of more salt-tolerant species. With increasing salinity, these systems may undergo further change to microbial mat-dominated systems composed mostly of cyanobacteria and halophilic bacteria. The effect of other environmental influences in mediating switches of vegetation was also examined. Colour and turbidity may play important roles at low to intermediate salinities [concentration of total dissolved solids (TDS) <10 000 mg L–1]; however, coloured or turbid wetlands are rarely found at intermediate to high salinities (>10 000 mg L–1 TDS). The role of nutrients remains largely unquantified in saline systems. We propose that alternative-states theory provides the basis of a conceptual framework for predicting impacts on wetlands affected by secondary salinisation. The ability to recognise and predict a change in state with changes in salinity adds a further tool to decision-making processes. A change in state represents a fundamental change in ecosystem function and may be difficult to reverse. This information is also important for the development of restoration strategies. Further work is required to better understand the influence of temporal variation in salinity on vegetation states and probable hysteresis effects.
5
Merrick, CJ, e GG Ganf. "Effects of zooplankton grazing on phytoplankton communities in Mt Bold Reservoir, South Australia, using enclosures". Marine and Freshwater Research 39, n. 4 (1988): 503. http://dx.doi.org/10.1071/mf9880503.
Testo completoAbstract (sommario):
Enclosure experiments demonstrated that zooplankton grazing changed the composition of the phytoplankton community in Mt Bold Reservoir. Phytoplankton biomass as measured by chlorophyll a did not change within the enclosures but changed across the experiments in response to zooplankton grazing. The chlorophyll a : phaeophytin a ratio did not reflect zooplankton grazing activity. Phytoplankton species richness and diversity did not change but the frequencies of many individual phytoplankton taxa differed in response to zooplankton grazing. Neither taxonomic identity nor phytoplankton size as measured by greatest axial linear dimension and volume determined the susceptibility of a taxon to grazing. This suggests that other criteria are important in food selection, criteria which vary between experiments. Multivariate statistical techniques successfully differentiated the grazed and the ungrazed phytoplankton communities based on the different frequencies of the component taxa. There was an indication that, within the enclosures, zooplankton grazing advanced the phytoplankton community along a temporal path. Microzooplankton grazing was not examined in these experiments but there was evidence that it was significant.
6
Gouws, Gavin, Barbara A. Stewart e Savel R. Daniels. "Phylogeographic structure of a freshwater crayfish (Decapoda:Parastacidae:Cherax preissii) in south-western Australia". Marine and Freshwater Research 57, n. 8 (2006): 837. http://dx.doi.org/10.1071/mf05248.
Testo completoAbstract (sommario):
Although phylogeographic patterns of freshwater decapods elsewhere in Australia are well documented, little is known of the phylogeography and biogeography of the endemic freshwater fauna of south-western Australia. Here, the phylogeographic structure of a freshwater crayfish, Cherax preissii Erichson, 1846, was investigated to determine contemporary and historical patterns of gene flow and to examined evolutionary and biogeographical scenarios. Allozyme and cytochrome c oxidase subunit I mitochondrial DNA data were collected from 15 populations, sampled across the known C. preissii distribution. Both markers revealed a clear distinction and separation among populations occurring in the north-western and southern portions of the distribution. Inferences of allopatric fragmentation and molecular dating attributed the divergence of the aquatic fauna of these regions to periods of Pliocene–Pleistocene aridity. Connectivity appeared to be greater within each of these regions. Evidence suggested contemporary, but not ongoing, gene flow, particularly within the southern region. This was possibly facilitated by dispersal during pluvial Pleistocene periods or drainage connectivity during episodic marine regressions. The divergence and distributions of these lineages parallels patterns seen in other freshwater crayfish of the region. More explicit investigation of these and further fine-scale phylogeographic studies may contribute to the understanding of biogeography and evolution in the south-west, and may further refine currently recognised biogeographical regions.
7
Bowling, LC. "Optical properties, Nutrients and Phytoplankton of freshwater Coastal Dune Lakes in South-east Queensland". Marine and Freshwater Research 39, n. 6 (1988): 805. http://dx.doi.org/10.1071/mf9880805.
Testo completoAbstract (sommario):
Gilvin was the main attenuator of photosynthetically available radiation (PAR) in 26 freshwater coastal dune lakes, despite most being only slightly humic (range 0.000-27.866 m-1, median = 1.088 m-1). Most were also non-turbid [range 0.27-3.00 nephelometric turbidity units (NTU), median = 0.77 NTU] and had low concentrations of chlorophyll a (range 0.212-15.869 �g I-1, median = 3.285 �g I-1). Accordingly there was only slight to moderate attenuation of PAR in most lakes, the majority having mean downwelling vertical attenuation coefficients of less than 1.0 m-1. However, Secchi depths indicate that the lake waters were more transparent during this study than previously reported in the literature. The lakes were typically oligotrophic, acidic, and of low conductivity. Desmids and Peridinium spp. dominated the phytoplankton, although Dynobryon cylindricum Imhof. and various Chlorococcales were also common.
8
Casanova, Michelle T., Annabel Douglas-Hill, Margaret A. Brock, Monika Muschal e Michael Bales. "Farm ponds in New South Wales, Australia: relationship between macrophyte and phytoplankton abundances". Marine and Freshwater Research 48, n. 4 (1997): 353. http://dx.doi.org/10.1071/mf96131.
Testo completoAbstract (sommario):
The physical, chemical and biological characteristics of 65 farm ponds in the Northern Tablelands and Central Western Slopes regions of New South Wales, Australia, were similar to those recorded for Australian ponds in other studies. The strongest single relationship between physico-chemical characteristics and biological characteristics was for high abundance of phytoplankton, low abundance of macrophytes, high turbidity, and high nutrient concentrations in ponds on granitic soil. Variation among the ponds was such that no other relationship was significant. Five groups of ponds were discerned on the basis of their biological and physico-chemical characteristics. One group could be classed as reasonably ‘pristine’, with high water clarity and high abundance of macrophytes; another group presented highly eutrophic, phytoplankton-dominated conditions. Ponds in these two groups can be described as being in ‘alternative stable states’. A third group had been modified with the intention of improving the appearance or utility of the ponds. The last two groups identified in this analysis had no specific parallels in the literature. Abundance of macrophytes was related to good water quality, and encouragement of increased abundance of submerged plants in farm ponds could result in improved water quality.
9
Lough, Janice M., e Alistair J. Hobday. "Observed climate change in Australian marine and freshwater environments". Marine and Freshwater Research 62, n. 9 (2011): 984. http://dx.doi.org/10.1071/mf10272.
Testo completoAbstract (sommario):
The consequences of human activities increasing concentrations of atmospheric greenhouse gases are already being felt in marine and terrestrial environments. More energy has been trapped in the global climate system, resulting in warming of land and sea temperatures. About 30% of the extra atmospheric carbon dioxide has been absorbed by the oceans, increasing their acidity. Thermal expansion and some melting of land-based ice have caused sea level to rise. Significant climate changes have now been observed across Australia and its coastal seas. The clearest signal is the warming of air and sea temperatures and the rates of warming have accelerated since the mid-20th century. Ocean warming has been higher than the global average around Australia, especially off south-eastern Australia. Changes in Australia’s hydrological regime are more difficult to differentiate from the high natural inter-annual variability. Recent trends towards drier winters in south-western Western Australia and part of southern Australia appear, however, to be largely attributable to human-induced climate change. Even without significant changes in average rainfall, warmer temperatures increase evaporative losses, enhance the intensity of recent droughts and reduce river flows. Sustained and coordinated monitoring of the physical environment, especially lacking for Australia’s freshwater ecosystems, is important to assess the magnitude and biological consequences of ongoing changes.
10
Lymbery, A. J., M. Hassan, D. L. Morgan, S. J. Beatty e R. G. Doupé. "Parasites of native and exotic freshwater fishes in south-western Australia". Journal of Fish Biology 76, n. 7 (13 aprile 2010): 1770–85. http://dx.doi.org/10.1111/j.1095-8649.2010.02615.x.
Testo completo
11
Kobayashi, Tsuyoshi, e Anthony G. Church. "Role of nutrients and zooplankton grazing on phytoplankton growth in a temperate reservoir in New South Wales, Australia". Marine and Freshwater Research 54, n. 5 (2003): 609. http://dx.doi.org/10.1071/mf02025.
Testo completoAbstract (sommario):
The role of nitrogen (N) and phosphorus (P) and zooplankton grazing on the growth of a phytoplankton community was investigated at different times in the Ben Chifley reservoir. In situ nutrient enrichment bioassays (n�= 12) indicated that phytoplankton growth was limited by P in 33% of experiments, by both N and P in 25% of experiments and no limitation was found in 42%. The hypothesis that N or P limitation occurred when ambient N : P ratios were different from the Redfield ratio was supported in 33% of bioassay experiments, suggesting that ambient N : P ratios do not always correctly indicate if N or P is limiting. Grazing rates of the reservoir zooplankton (>150�μm in size) ranged from 0.023–0.199 day–1 (mean: 0.078 day–1, n = 8). The grazing efficiency, as measured by a weight-specific clearance rate, ranged from 0.049–0.743 mL μg dry wt–1 day–1, and was positively correlated with the relative biomass of Daphnia in the community. The nutrient-stimulated growth of phytoplankton ranged from 0.085–1.031 day–1 (mean: 0.461 day–1, n = 10). The effect of nutrient enrichment exceeded that of zooplankton grazing in 62% of experiments. Further study is necessary to understand a qualitative effect of nutrients and zooplankton grazing on the phytoplankton community structure in the Ben Chifley reservoir.
12
Beatty, Stephen J., David L. Morgan e Howard S. Gill. "Reproductive biology of the large freshwater crayfish Cherax cainii in south-western Australia". Marine and Freshwater Research 54, n. 5 (2003): 597. http://dx.doi.org/10.1071/mf02077.
Testo completoAbstract (sommario):
The reproductive biology of Cherax cainii was studied in an impoundment dam in south-western Australia using histological examination of ovarian development (previous studies describing the reproductive biology of freshwater crayfish have relied solely on macroscopic descriptions of gonadal development). Spawning occurred between August and November and peaked in late August and September, with the percentage of berried females increasing from 50% in September to 96% in November before declining to 11% in December. Juveniles were released from berried females between late November and early December. Female gonads recovered dramatically after spawning with 81% of mature females possessing stage IV (maturing) gonads in March. The respective orbital carapace lengths at which 50 and 95% of C. cainii reached maturity were 32.1 and 37.9 mm for females, and 28.6 and 38.8 mm for males. The mean potential fecundity (i.e. number of mature ovarian oocytes prior to spawning) was 443 compared with 286 for the mean effective fecundity (i.e. number of pleopodal eggs, embryos or juveniles following spawning). The fact that the full ovarian reproductive potential of C. cainii is not attained is probably due to the limitation of egg attachment space on the pleopods.
13
Entwisle, Timothy J., e John Huisman. "Algal systematics in Australia". Australian Systematic Botany 11, n. 2 (1998): 203. http://dx.doi.org/10.1071/sb97006.
Testo completoAbstract (sommario):
Documentation of the algal flora of Australia had its beginnings in the seventeenth century and has progressed sporadically but with increasing vigour ever since. Earlier studies dealing with Australian algae were undertaken by overseas phycologists working with specimens collected during scientific voyages or short visits. Recent floristic studies have concentrated on specific regions, isolated localities, or particular taxonomic or ecological groupings. The algal flora of Australia is unevenly documented: northern Australia remains largely uncollected for seaweeds and marine phytoplankton, freshwater algal sampling sites are eclectically scattered across Australia, and collecting of terrestrial algae has been almost completely neglected. At present, numbers and names of species reported from Australia can only be provisional, and an immense amount of floristic and revisionary work is needed before we can match our current knowledge of the vascular plant flora. Until recently, documentation of records was poor and voucher material seldom adequate. We recommend extensive collecting, thorough taxonomic revisions, and regular contribution to Floras and guidebooks. A critical corollary is the training and employment of systematic phycologists in Australian herbaria and universities. Only then can we follow the path that leads ‘beyond the Floras’.
14
Harvey, MS. "Pezidae, a new freshwater mite family from Australia (Acarina : Halacaroidea)". Invertebrate Systematics 3, n. 6 (1989): 771. http://dx.doi.org/10.1071/it9890771.
Testo completoAbstract (sommario):
A new halacaroid family, Pezidae, is erected for the new genus Peza, with two new species Peza ops (type species) and Peza daps. P. ops has been widely collected in south-eastern Australia, while P. daps is known only from a single female taken from the gill chamber of a burrowing crayfish, Engaeus fultoni Smith & Schuster (Crustacea : Decapoda : Parastacidae), in the Otway Ranges, Victoria. During winter and spring, females of both species apparently attach their eggs to their hind legs. The Pezidae is regarded as the sister-group of the remaining Halacaroidea.
15
Li, Qian P., Weiwen Zhou, Yinchao Chen e Zhengchao Wu. "Phytoplankton response to a plume front in the northern South China Sea". Biogeosciences 15, n. 8 (27 aprile 2018): 2551–63. http://dx.doi.org/10.5194/bg-15-2551-2018.
Testo completoAbstract (sommario):
Abstract. Due to a strong river discharge during April–June 2016, a persistent salinity front, with freshwater flushing seaward on the surface but seawater moving landward at the bottom, was formed in the coastal waters west of the Pearl River estuary (PRE) over the northern South China Sea (NSCS) shelf. Hydrographic measurements revealed that the salinity front was influenced by both the river plume and coastal upwelling. On shipboard nutrient-enrichment experiments with size-fractionation chlorophyll a measurements were taken on both sides of the front as well as in the frontal zone to diagnose the spatial variations of phytoplankton physiology across the frontal system. We also assessed the size-fractionated responses of phytoplankton to the treatment of plume water at the frontal zone and the sea side of the front. The biological impact of vertical mixing or upwelling was further examined by the response of surface phytoplankton to the addition of local bottom water. Our results suggested that there was a large variation in phytoplankton physiology on the sea side of the front, driven by dynamic nutrient fluxes, although P limitation was prevailing on the shore side of the front and at the frontal zone. The spreading of plume water at the frontal zone would directly improve the growth of microphytoplankton, while nano- and picophytoplankton growths could have become saturated at high percentages of plume water. Also, the mixing of bottom water would stimulate the growth of surface phytoplankton on both sides of the front by altering the surface N∕P ratio to make it closer to the Redfield stoichiometry. In summary, phytoplankton growth and physiology could be profoundly influenced by the physical dynamics in the frontal system during the spring–summer of 2016.
16
Dove, A. D. M., T. H. Cribb, S. P. Mockler e M. Lintermans. "The Asian fish tapeworm, Bothriocephalus acheilognathi, in Australian freshwater fishes". Marine and Freshwater Research 48, n. 2 (1997): 181. http://dx.doi.org/10.1071/mf96069.
Testo completoAbstract (sommario):
Bothriocephalus acheilognathi was collected from 13 of 38 carp (Cyprinus carpio), 2 of 4 mosquito fish (Gambusia holbrooki), and 2 of 12 western carp gudgeon (Hypseleotris klunzingeri ) in waterways of the Australian Capital Territory and New South Wales. This is the first record of this parasite in Australia, and its presence in H. klunzingeri is a new host record. B. acheilognathi presumably arrived in Australia with its introduced fish hosts and has since crossed into native fishes. This cestode may infect other native fish species, a potential that is significant given the high pathogenicity associated with infection in other known hosts.
17
Rochelle-Newall, E. J., V. T. Chu, O. Pringault, D. Amouroux, R. Arfi, Y. Bettarel, T. Bouvier et al. "Phytoplankton diversity and productivity in a highly turbid, tropical coastal system (Bach Dang Estuary, Vietnam)". Biogeosciences Discussions 8, n. 1 (18 gennaio 2011): 487–525. http://dx.doi.org/10.5194/bgd-8-487-2011.
Testo completoAbstract (sommario):
Abstract. The factors controlling estuarine phytoplankton diversity and production are relatively well known in temperate systems. Less however is known about the factors affecting phytoplankton community distribution in tropical estuaries. This is surprising given the economic and ecological importance of these large, deltaic ecosystems, such as are found in South East Asia. Here we present the results from an investigation into the factors controlling phytoplankton distribution and phytoplankton-bacterial coupling in the Bach Dang Estuary, a sub-estuary of the Red River system, in Northern Vietnam. Phytoplankton diversity and primary and bacterial production, nutrients and metallic contaminants (mercury and organotin) were measured during two seasons: wet (July 2008) and dry (March 2009). Phytoplankton community composition differed between the two seasons with only a 2% similarity between July and March. The large spatial extent and complexity of defining the freshwater sources meant that simple mixing diagrams could not be used in this system. We therefore employed multivariate analyses to determine the factors influencing phytoplankton community structure. Salinity and suspended particulate matter were important factors in determining phytoplankton distribution, particularly during the wet season. We also show that phytoplankton community structure is probably influenced by the concentrations of mercury species (inorganic mercury and methyl mercury in both the particulate and dissolved phases) and of tri-, di, and mono-butyl tin species found in this system. Freshwater phytoplankton community composition was associated with dissolved methyl mercury and particulate inorganic mercury concentrations during the wet season, whereas, during the dry season, dissolved methyl mercury and particulate butyl tin species were important factors for the discrimination of the phytoplankton community structure. Phytoplankton-bacterioplankton coupling was also investigated during both seasons. In the inshore, riverine stations the ratio between bacterial production and dissolved primary production was high supporting the hypothesis that bacterial carbon demand is supported by allochthonous riverine carbon sources. The inverse was true in the offshore stations, where BP:DPP values were less than 1, potentially reflecting differences in primary production due to shifting phytoplankton community diversity.
18
Foissner, W., e PJ O'Donoghue. "Morphology and infraciliature of some freshwater ciliates (Protozoa : Ciliophora) from Western and South Australia". Invertebrate Systematics 3, n. 6 (1989): 661. http://dx.doi.org/10.1071/it9890661.
Testo completoAbstract (sommario):
Thirteen new or little-known freshwater ciliates from Perth, W.A., and Adelaide, S.A., are described: Urotricha furcata Schewiakoff, 1892; Coleps amphacanthus Ehrenberg, 1833; Fuscheria nodosa Foissner, 1983; Lacrymaria australis, sp. nov.; Acineria uncinata Tucolesco, 1962; Litonotus lamella (Mnller, 1773); Loxophyllum australe, sp. nov.; Naxella australis, sp. nov.; Microthorax australis, sp. nov.; Blepharisma americanum (Suzuki, 1954); Stenosemella lacustris, sp. nov.; Oxytricha australis, sp. nov.; and Urosomoida perthensis, sp. nov. Descriptions are based on live observations, protargol and silver nitrate stained specimens and biometry. All species represent new records for the fauna of Australia. A new species, Naxella faurei, sp. nov., is established for Nassula lateritia Faure-Fremiet, 1967 and a new diagnosis is given for Litonotus lamella (Mnller, 1773).
19
Beatty, Stephen J., David L. Morgan, Mahmoud Rashnavadi e Alan J. Lymbery. "Salinity tolerances of endemic freshwater fishes of south-western Australia: implications for conservation in a biodiversity hotspot". Marine and Freshwater Research 62, n. 1 (2011): 91. http://dx.doi.org/10.1071/mf10100.
Testo completoAbstract (sommario):
Secondary salinisation represents an important threat to terrestrial and aquatic habitats throughout the world. In south-western Australia, widespread salinisation of waterways has caused large range reductions in the highly endemic freshwater fish fauna. We hypothesised that differences in the distributions of three fish species within the salinised Blackwood River would be related to their salinity tolerances. Galaxias occidentalis was widespread throughout the catchment, whereas Nannoperca vittata was restricted to the main channel and freshwater tributaries of the lower catchment, and Nannatherina balstoni was restricted to those tributaries and a perennial section of the main channel that received a considerable amount of fresh groundwater. Acute salinity tolerances (Effect Concentrations) of G. occidentalis and N. vittata were similar (EC50 ∼14.6 g L–1), but significantly greater than that of N. balstoni (EC50 ∼8.2 g L–1). The greater geographical range of G. occidentalis, compared with N. vittata, may be a consequence of the dispersal capability of the former species, and the lower salinity tolerance of N. balstoni contributes to its highly restricted range. The findings demonstrate that secondary salinisation has greatly impacted these freshwater fishes, and fresh groundwater refuges, predicted to decrease due to reduced rainfall, appear crucial in maintaining remnant populations.
20
Walsh, CJ, e BD Mitchell. "The Freshwater shrimp Paratya australiensis (Kemp, 1917) (Decapoda:Atyidae) in estuaries of south-westren victoria, Australia". Marine and Freshwater Research 46, n. 6 (1995): 959. http://dx.doi.org/10.1071/mf9950959.
Testo completoAbstract (sommario):
All life-cycle stages of Paratya australiensis, formerly thought to occur predominantly in freshwater environments, were found to be common in estuaries of western Victoria. Highest densities of larvae were found below the halocline in stable, open, well developed, salt-wedge estuaries. Larvae developed in the salt wedge, and juveniles recruited to littoral weed beds. Adults were most abundant in low salinities among submerged, leafy macrophytes. Although recruitment to estuaries permits the avoidance of fatal drift of larvae to sea, tolerance of saline conditions may permit rare dispersal of larvae between estuaries. A new model for the biogeography of Paratya is proposed.
21
Hanson, Christine E., Charitha B. Pattiaratchi e Anya M. Waite. "Seasonal production regimes off south-western Australia: influence of the Capes and Leeuwin Currents on phytoplankton dynamics". Marine and Freshwater Research 56, n. 7 (2005): 1011. http://dx.doi.org/10.1071/mf04288.
Testo completoAbstract (sommario):
Temporal primary production dynamics were investigated off south-western Australia, where the summer upwelling regime of the Capes Current was compared with early winter conditions characterised by strengthened near-shore Leeuwin Current flow. Seasonal upwelling in this region sourced nitrate levels of ≥1 μm from the nutricline at the base of the Leeuwin Current’s mixed layer, with total water column production reaching a maximum of ~950 mg C m−2 day−1 in the Capes Current. Stable isotope signatures of particulate matter indicated that productivity off south-western Australia was heavily reliant on nitrate as a nitrogen source, with mean δ15N ranging from ~4 to 5 ‰ under both upwelling and non-upwelling (winter) conditions. Unexpectedly, significant nutrient enrichment within the Leeuwin Current (up to 3.1 μm nitrate) occurred during winter, likely as a result of the meandering Leeuwin Current flooding the inner shelf north of the study area and entraining relatively high-nutrient shelf waters in its southwards flow. However, early winter production under these nutrient-replete conditions (mean ± s.d. 310 ± 105 mg C m−2 day−1) was significantly lower than in summer (695 ± 140 mg C m−2 day−1) due to light limitation, both as a result of reduced surface irradiance characteristic of the winter months and significantly higher light attenuation within the water column as compared with summer conditions.
22
Hallegraeff, GM, e SW Jeffrey. "Annually recurrent diatom blooms in spring along the New South Wales coast of Australia". Marine and Freshwater Research 44, n. 2 (1993): 325. http://dx.doi.org/10.1071/mf9930325.
Testo completoAbstract (sommario):
Blooms of phytoplankton (100-280 mg chlorophyll a m-1) occur on the continental shelf off Sydney in the spring of most years. These sudden chlorophyll increases (more than 10 times the normal algal biomass) are due to short-lived diatom blooms that evolve in a predictable sequence from small chainforming species (Nitzschia, Thalassiosira) to large centric species (Lauderia, Rhizosolenia) and eventually to large dinoflagellates (Protoperidinium). Two research cruises (October 1981, September 1984) were conducted to define the longshore extent of this phenomenon. Diatom blooms were widespread along the whole New South Wales coastline, occurring in the 700-km-long region from Cape Hawke in the north (32°S), where the East Australian Current separates from the coast, to Maria Island off Tasmania in the south (43°S). Hydrological mechanisms of these annually recurrent enrichments are related to the action of the East Australian Current and are unlike those triggering spring blooms in temperate European waters. Implications of these diatom blooms for coastal fisheries along the New South Wales coast are briefly discussed.
23
Koehn, John D., Scott M. Raymond, Ivor Stuart, Charles R. Todd, Stephen R. Balcombe, Brenton P. Zampatti, Heleena Bamford et al. "A compendium of ecological knowledge for restoration of freshwater fishes in Australia". Marine and Freshwater Research 71, n. 11 (2020): 1391. http://dx.doi.org/10.1071/mf20127.
Testo completoAbstract (sommario):
Many freshwater fishes are imperilled globally, and there is a need for easily accessible, contemporary ecological knowledge to guide management. This compendium contains knowledge collated from over 600 publications and 27 expert workshops to support the restoration of 9 priority native freshwater fish species, representative of the range of life-history strategies and values in south-eastern Australia’s Murray–Darling Basin. To help prioritise future research investment and restoration actions, ecological knowledge and threats were assessed for each species and life stage. There is considerable new knowledge (80% of publications used were from the past 20 years), but this varied among species and life stages, with most known about adults, then egg, juvenile and larval stages (in that order). The biggest knowledge gaps concerned early life stage requirements, survival, recruitment, growth rates, condition and movements. Key threats include reduced longitudinal and lateral connectivity, altered flows, loss of refugia, reductions in both flowing (lotic) and slackwater riverine habitats, degradation of wetland habitats, alien species interactions and loss of aquatic vegetation. Examples and case studies illustrating the application of this knowledge to underpin effective restoration management are provided. This extensive ecological evidence base for multiple species is presented in a tabular format to assist a range of readers.
24
Baker, Andrew M., Jane M. Hughes, John C. Dean e Stuart E. Bunn. "Mitochondrial DNA reveals phylogenetic structuring and cryptic diversity in Australian freshwater macroinvertebrate assemblages". Marine and Freshwater Research 55, n. 6 (2004): 629. http://dx.doi.org/10.1071/mf04050.
Testo completoAbstract (sommario):
Freshwater catchments of south-east Australia possess generally rich and diverse macroinvertebrate faunas, although the genetic structuring of these assemblages is poorly known. In this study, we assessed mitochondrial phylogenetic structure within four genera of macroinvertebrates from the Sydney Water Supply Catchment, south-east Australia: Euastacus (parastacid crayfish), Cheumatopsyche (hydropsychid caddisflies), Atalophlebia (leptophlebiid mayflies) and Paratya (atyid shrimp), with a view to prioritising areas of high diversity for future conservation efforts. We found extremely divergent (≈4–19%) cytochrome c oxidase subunit I (COI) lineages within all surveyed groups, many of which corresponded to recognised taxa, although there was also evidence of cryptic species within three genera; Euastacus, Atalophlebia and Paratya. Distributions of these three genera were associated with high altitude streams, above dam impoundments. Our results have important implications for management of the Sydney Water Supply Catchment. Future disturbance in this region is likely to be high and priority should be directed towards preserving the diversity of fauna in these upland areas. This comparative phylogenetic approach may have value as a means to focus and direct conservation efforts in other areas supporting high biodiversity.
25
Kefford, Ben J., Carolyn G. Palmer e Dayanthi Nugegoda. "Relative salinity tolerance of freshwater macroinvertebrates from the south-east Eastern Cape, South Africa compared with the Barwon Catchment, Victoria, Australia". Marine and Freshwater Research 56, n. 2 (2005): 163. http://dx.doi.org/10.1071/mf04098.
Testo completoAbstract (sommario):
Salinity is rising in many southern African and Australian rivers with unknown effects on aquatic organisms. The extent of spatial variation, at any scale, in salt tolerances of aquatic organisms is unknown, so whether data from one location is applicable elsewhere is also unknown. The acute tolerances (72-h median lethal concentration (LC50)) to sea salt of 49 macroinvertebrate taxa from the south-east Eastern Cape (SEEC), South Africa were compared with those of 57 species from the Barwon Catchment, Victoria, Australia. The mean LC50 values from both locations were similar (Barwon: 31 and SEEC: 32 mS cm−1) and less abundant (rare) taxa tended to be more tolerant than more abundant (common) taxa. There was, however, a greater range of LC50 values (5.5–76 mS cm−1) in the Barwon Catchment than in the SEEC (11–47 mS cm−1). The species sensitivity distribution (SSD) for SEEC taxa was bimodal whereas the Barwon Catchment’s SSD had a single peak. With few exceptions, members of an order had similar tolerances in both locations. The differences in SSD between locations were related to crustacean, odonate and non-arthropod relative richness. Although it is not ideal to extrapolate SSDs from one location to another, it may be reasonable to assume similar salinity tolerances among related taxa.
26
Lintermans, Mark. "A review of on-ground recovery actions for threatened freshwater fish in Australia". Marine and Freshwater Research 64, n. 9 (2013): 775. http://dx.doi.org/10.1071/mf12306.
Testo completoAbstract (sommario):
Freshwater fish are a highly threatened group and recovery of these threatened species is an increasingly difficult ecological and social challenge. There are many different on-ground recovery actions available to managers, but no synthesis of what, how or why these recovery actions have been deployed. The present paper reviews 428 reported on-ground recovery actions from a survey of practitioners of threatened freshwater-fish recovery in Australia. Recovery actions were grouped into 12 categories, with the most commonly utilised recovery categories being harvest control, translocation, habitat enhancement and stock enhancement. Major drivers of recovery actions were general conservation concern, recovery plans and emergency responses. The number of recovery actions grew significantly in the decade beginning 2000 as the impacts of prolonged drought in south-eastern Australia intensified. In all, 58% of recovery actions occurred in the Murray–Darling Basin, although this region holds only 27% of the 74 listed threatened freshwater fish in Australia. Few or no recovery actions were reported for many species, and few actions occurred in northern or western parts of the country. More than 80% of recovery actions reportedly had some form of monitoring. The diversity of management interventions is reviewed, and patterns and issues are identified to guide future recovery efforts.
27
KING, RACHAEL A. "Two new genera and species of chiltoniid amphipods (Crustacea: Amphipoda: Talitroidea) from freshwater mound springs in South Australia". Zootaxa 2293, n. 1 (19 novembre 2009): 35–52. http://dx.doi.org/10.11646/zootaxa.2293.1.2.
Testo completoAbstract (sommario):
Amphipods within the family Chiltoniidae are an abundant yet taxonomically poorly known member of Australian freshwater habitats. With only four species known from Australia, the group is inadequately defined and marked by taxonomists as difficult to identify. Recent molecular analyses of chiltoniids from mound springs in South Australia detected several distinct species, prompting a morphological revision of material from the central and southern Lake Eyre region. Clear groups defined by unique combinations of morphological characters (focusing on uropodal, coxal, male gnathopod 2, and antennal morphology) were found that closely correlated with clades found in the molecular analyses. Arabunnachiltonia n. gen. is established for A. murphyi n. sp. from Strangways Springs in South Australia. Wangiannachiltonia n. gen. is established for W. guzikae n. sp. from Davenport Springs in South Australia. The chiltoniid genera are discussed and a key is presented to the known Australian species.
28
Entwisle, TJ. "A monograph of Vaucheria (Vaucheriaceae, Chrysophyta) in south-eastern mainland Australia". Australian Systematic Botany 1, n. 1 (1988): 1. http://dx.doi.org/10.1071/sb9880001.
Testo completoAbstract (sommario):
Twenty-five species of Vaucheria have been found in south-eastern Australia, from both freshwater and saline habitats. As many collections were sterile, the study of plants in culture was necessary for identification as well as for the evaluation of taxonomic characters. A reassessment of the sectional classification has led to the raising of the subsections Racemosae (Walz) Heering and Sessiles (Walz) Heering to sectional level. Of the nine sections of the genus recognised, six are represented in south-eastern Australia. A key has been provided to all sections and species found during the study. Twentyone species are new records for the continent, including the newly described V. bicornigera [section Tubuligerae (Walz) Heering sens, nov.], V. gyrogyna [section Racemosae (Walz) sect, nov.] and V. nanandra [section Corniculatae (Walz) Heering sens. nov.]. Two other species, V. gardneri Collins and V. subarechavaletae Borge, were previously only known from the U.S.A. and Argentina respectively. The salient morphological features of all species have been illustrated with light micrographs or with scanning electron micrographs.
29
Shao, N. F., S. T. Yang, Y. Sun, Y. Gai, C. S. Zhao, F. Wang, X. Yin e B. Dong. "Assessing aquatic ecosystem health through the analysis of plankton biodiversity". Marine and Freshwater Research 70, n. 5 (2019): 647. http://dx.doi.org/10.1071/mf18342.
Testo completoAbstract (sommario):
Healthy plankton communities are the foundation of many freshwater food webs. Their biodiversity is often used to directly reflect the health of the rivers. Globally, river ecosystem restoration is a critical issue and many freshwater ecosystems, especially in cities, are degraded because of intensive human activities. This is true for Jinan, China’s first pilot city for the Water Ecological Civilisation Project. The outcomes of aquatic ecosystem restoration in the city will directly affect the success or failure of the construction of aquatic ecological civilisations across the entire country; therefore, there is an urgent need for research on the assessment of river health in Jinan based on plankton biodiversity. As such, this study gathered data on the distribution of plankton (phytoplankton and zooplankton) in Jinan by collecting three sets of samples from 59 aquatic ecosystem monitoring stations in spring, summer and autumn of 2015. In all, 104 species of phytoplankton and 56 species of zooplankton were identified. Diatoms, Chlorophyta, and Cyanophyta accounted for 50, 31 and 15% respectively of phytoplankton, and rotifers, Protozoa and cladocerans accounted for 39, 31 and 17% respectively of zooplankton. We constructed a plankton health assessment model based on the Shannon–Wiener diversity index for analysis of the temporal and spatial distribution. According to the overall health distribution diagram, spatially health status was significantly better in north and south Jinan than in the city centre; temporally, spring water ecosystem health was better than in summer and autumn. These conclusions provide a theoretical basis and direction for the restoration of aquatic ecosystems in Jinan, and the methods used in this study can serve as a reference for aquatic ecosystem evaluation in developing countries.
30
Boon, Paul I. "Are mangroves in Victoria (south-eastern Australia) already responding to climate change?" Marine and Freshwater Research 68, n. 12 (2017): 2366. http://dx.doi.org/10.1071/mf17015.
Testo completoAbstract (sommario):
The distribution and productivity of mangroves is directly affected by a wide range of climatic drivers, including temperature, frost, rainfall, evaporation and storm activity, which, in turn, influence a suite of secondary drivers, including changes in freshwater run-off and sediment supply, groundwater dynamics and inter-species competitiveness. The highest-latitude expression of mangroves globally is at Millers Landing, Victoria (38°45′S), and because the vigour and productivity of mangroves across much of Victoria is thought to be limited by low winter temperatures and the incidence and severity of frosts, it is likely that mangroves will be among the first plant communities to be affected by climate change in coastal south-eastern Australia. An increase in plant vigour is likely, but there are almost no historical data with which to compare current rates of primary production. An extension of mangroves to higher latitudes on the mainland is impossible because of the geomorphology of the land that lies further to the south. Small-scale changes in distribution, including the progressive encroachment of mangroves into coastal saltmarsh, are likely to be among the clearest indications of the response of mangroves to a warming climate. Increased effort into tracking changes in mangrove vigour, productivity and distribution is clearly warranted.
31
Zeidler, Wolfgang, e M. Adams. "Revision of the Australian crustacean genus of freshwater crayfish Gramastacus Riek (Decapoda : Parastacidae)". Invertebrate Systematics 3, n. 7 (1989): 913. http://dx.doi.org/10.1071/it9890913.
Testo completoAbstract (sommario):
The Australian freshwater crayfish genus Gramastacus, previously consisting of two species known only from type localities, is revised utilising newly collected material ranging from The Grampians, Victoria, to the south-east, of South Australia. Morphological and biochemical studies demonstrate that Granzastacus is monotypic with G. insolitus Riek, 1972 the only species. Morphological comparisons between Granmstacus and Geocharax are also made, and although Gramastacus is similar to Geocharax, sufficient differences were found to uphold the generic status of Granlastacus. G. insolitus is a swamp-living species whose survival is threatened by further drainage of remaining known localities.
32
Lemley, DA, JB Adams e JL Largier. "Harmful algal blooms as a sink for inorganic nutrients in a eutrophic estuary". Marine Ecology Progress Series 663 (31 marzo 2021): 63–76. http://dx.doi.org/10.3354/meps13655.
Testo completoAbstract (sommario):
Phytoplankton-mediated nutrient fluxes typically provide only pulsed relief to adjacent coastal waters during the productive period, with nutrient export increasing in the absence of substantial phytoplankton biomass. On the warm temperate coastline of South Africa, the Sundays Estuary is characterised by highly regulated freshwater inflow patterns, nutrient-enriched conditions, and resident harmful algal blooms (HABs). Given these attributes, the study objective was to investigate the effect of these phytoplankton blooms on fluvial inorganic nutrient dynamics. To assess uptake, we analysed inorganic nutrient (phosphate, ammonium, NOx) and phytoplankton concentrations in relation to salinity using data from 17 surveys. Property-salinity mixing diagrams and statistical analyses indicated a positive association between increasing phytoplankton biomass and decreasing NOx flux (p < 0.001), and to a lesser degree phosphate flux (p = 0.22), along the gradient from low-salinity inner estuary to high salinity outer estuary. High biomass HAB accumulations of Heterosigma akashiwo (>100 µg chl a l-1) represent significant removal of available NOx (~100%) and phosphate (>75%) during warmer conditions (>20°C). These events, together with continuous inorganic nutrient uptake during less severe bloom conditions, remove a substantial portion of annual NOx and phosphate loads (36.5 and 36.4% flux, respectively). Although this buffers inorganic nutrient loading to adjacent coastal waters, it also represents an emerging legacy pollution issue in the form of a benthic accumulation of organic material in bottom waters subject to recurrent hypoxia. Future management efforts should adopt an ecosystem-based approach centred around simultaneous restoration of hydrological variability and dual nutrient reduction strategies (N and P).
33
Bayly, IAE. "Distinctive aspects of the zooplankton of large lakes in Australasia, Antarctica and South America". Marine and Freshwater Research 46, n. 8 (1995): 1109. http://dx.doi.org/10.1071/mf9951109.
Testo completoAbstract (sommario):
Not only has the degree of species-level cosmopolitanism amongst zooplanktonic organisms been considerably overestimated, but differences between the different classical biogeographic regions (established from terrestrial studies) occur at supra-specific levels as high as family or even suborder. The Centropagidae, and particularly the genus Boeckella, are found in New Zealand, most of Australia, southern and high altitude regions of South America, and around the periphery of Antarctica. The biogeography and ecology of this family is discussed in detail. Most predaceous families of Cladocera are entirely absent from the Australian and Neotropical regions. The genus Daphniopsis occurs in salt lakes in Australia and South America and in freshwater lakes in Antarctica. In southern Australia numerous species of ostracod have colonized the limnetic region of salt lakes, and the largest of these prey on species of Calamoecia, Daphniopsis and small ostracods. Chaoboridae are absent from New Zealand as, too, are obligate planktivorous fish. The Chilean flamingo, Phoenicopterus chilensis, and Wilson's phalarope, Phalaropus tricolor, are significant predators on Boeckella poopoensis in salt lakes on the Andean Altiplano and elsewhere in South America.
34
Faulks, Leanne K., Dean M. Gilligan e Luciano B. Beheregaray. "Phylogeography of a threatened freshwater fish (Mogurnda adspersa) in eastern Australia: conservation implications". Marine and Freshwater Research 59, n. 1 (2008): 89. http://dx.doi.org/10.1071/mf07167.
Testo completoAbstract (sommario):
Phylogeography is a field that has the potential to provide an integrative approach to the conservation of threatened species. The southern purple spotted gudgeon, Mogurnda adspersa, is a small freshwater fish that was once common and widely distributed throughout south-eastern Australia. However, habitat alteration has dramatically reduced the size and the range of Murray–Darling Basin populations, which are now classified as endangered. Here patterns of genetic structure and evolutionary history of M. adspersa in southern Queensland and the Murray–Darling Basin are elucidated using three regions of the mitochondrial DNA, the ATPase 6 and 8 and the control region. Murray–Darling Basin populations are characterised by lineages with highly localised endemism, very low genetic diversity and restricted gene flow. Phylogenetic reconstructions show that Murray–Darling Basin populations comprise a monophyletic clade that possibly originated by range expansion from the coast around 1.6 million years ago. It is proposed that the divergent Murray–Darling Basin clade is of high conservation priority and requires separate management. The present study further exemplifies the role of drainage rearrangement in driving evolutionary diversification in Australian freshwater fishes, an historical process with profound implications for conservation management.
35
Crook, David A., Jed I. Macdonald e Tarmo A. Raadik. "Evidence of diadromous movements in a coastal population of southern smelts (Retropinninae: Retropinna) from Victoria, Australia". Marine and Freshwater Research 59, n. 7 (2008): 638. http://dx.doi.org/10.1071/mf07238.
Testo completoAbstract (sommario):
Understanding the migratory behaviour of fishes is critical to the conservation and management of fish assemblages in coastal rivers. We analysed the otolith chemical signatures of smelt, Retropinna sp., from inland and coastal populations in mainland south-eastern Australia to determine whether individuals within coastal populations of the species were diadromous. Assessments of otolith chemical composition combined with water chemistry data were used to make inferences about the migration histories of individual fish. A proportion of the smelt collected from the freshwater reaches of a coastal river exhibited diadromous movements, with the majority of fish analysed showing evidence of estuarine or marine occupation as larvae/juveniles and a minority inhabiting freshwater throughout their life histories. A broad range in the daily ages of upstream migration into freshwater (15–106 days) and the timing of these migrations suggest that spawning and migration occur over several months during the summer/autumn period. The results of this study suggest that southern smelts are an ecologically variable taxonomic group and that conservation and management actions should take into account the range of migratory behaviours exhibited both within populations and across regions.
36
Jerry, Dean R. "Phylogeography of the freshwater catfish Tandanus tandanus (Plotosidae): a model species to understand evolution of the eastern Australian freshwater fish fauna". Marine and Freshwater Research 59, n. 4 (2008): 351. http://dx.doi.org/10.1071/mf07187.
Testo completoAbstract (sommario):
The geologically complex eastern Australian coastal margin supports the highest taxonomic diversity of freshwater fishes on the continent. However, mechanisms leading to coastal biogeographic patterns are poorly understood. A 399-bp fragment of the hypervariable mtDNA control region was sequenced from populations of eel-tailed catfish (Tandanus tandanus) to determine their phylogeographic structure and to relate this to proposed biogeographic mechanisms and landform evolution. Genetic structure in Tandanus is complex, with haplotypes clustering into three lineages: a phylogenetically distant, northern Queensland clade that is probably a new species; a mid-northern New South Wales clade corresponding to the recently discovered ‘Bellinger’ Tandanus cryptic species; and a third ‘derived’ clade T. tandanus. Phylogenetic analyses suggest that eastern Australian Tandanus originally invaded freshwaters from the coast where volcanic activity in the north and increasing aridity from the Paleocene reduced inter-fluvial connections, causing genetic divergence of northern Queensland and mid-northern New South Wales populations. The haplotypes represented by Murray–Darling drainage T. tandanus were the most derived, indicating that this species originally evolved on the coast and subsequently colonised the Murray–Darling basin. Tandanus in eastern Australia is phylogenetically structured and possibly comprises three species in this region; a pattern potentially shared by other eastern Australian freshwater fishes.
37
Close, Paul G., Tom J. Ryan, David L. Morgan, Stephen J. Beatty e Craig S. Lawrence. "First record of ‘climbing’ and ‘jumping’ by juvenile Galaxias truttaceus Valenciennes, 1846 (Galaxiidae) from south-western Australia". Australian Journal of Zoology 62, n. 2 (2014): 175. http://dx.doi.org/10.1071/zo14004.
Testo completoAbstract (sommario):
Upstream migration of juvenile stages of temperate Australian amphidromous fish typically coincides with seasonally low river discharge when hydraulic (e.g. cascades) and physical (e.g. rock bars) barriers may be common. The ability to ‘climb’ or ‘jump’ may be expected to assist in negotiating low-flow barriers; however, it is presumed to be limited to a few native Australian freshwater fishes. Juvenile stages of Galaxias truttaceus Valenciennes, 1846 were observed ‘climbing’ and ‘jumping’ to successfully negotiate a low, vertical weir wall during their upstream recruitment migrations in south-western Australia. Based on this observation, we propose initial definitions for ‘climbing’ and ‘jumping’ to describe locomotory strategies employed by fishes to negotiate obstacles that would otherwise prevent free passage by normal swimming behaviour. Greater knowledge of the climbing, jumping and swimming performance, especially for small-bodied species and early life stages, will help improve the management of instream barriers for this critically endangered species and other freshwater fishes of southern Australia.
38
Tanimura, A., S. Kawaguchi, N. Oka, J. Nishikawa, S. Toczko, K. T. Takahashi, M. Terazaki, T. Odate, M. Fukuchi e G. Hosie. "Abundance and grazing impacts of krill, salps and copepods along the 140°E meridian in the Southern Ocean during summer". Antarctic Science 20, n. 4 (18 marzo 2008): 365–79. http://dx.doi.org/10.1017/s0954102008000928.
Testo completoAbstract (sommario):
AbstractAbundance and grazing impacts of krill, salps and herbivorous copepods were investigated in Antarctic waters along the 140°E meridian, south of Australia, during the summers of 2002 and 2003. North of the Southern Boundary of the Antarctic Circumpolar Current (SB-ACC), macrozooplankton comprised species of Salpa thompsoni and large herbivorous copepods, while the area south of the SB-ACC was numerically dominated by Euphausia superba or E. crystallorophias. North of the SB-ACC, the estimate of grazing impact revealed that krill, salps and copepods, Calanoides acutus, Calanus propinquus, Rhincalanus gigas and Metridia gerlachei, are able to remove a maximum of 37% of the total phytoplankton standing stock in early to midsummer, but grazing is negligible in late summer. The high grazing impact is attributed to the relatively high zooplankton abundance and low phytoplankton abundance. South of the SB-ACC, overall daily grazing impact of the three zooplankton groups was low and did not exceed 6% of the total phytoplankton standing stock throughout the investigation period. Present results indicate that the contribution of krill, salps and copepods varies seasonally as well as regionally across the SB-ACC. It seems that the carbon transport from surface to deep water by macro- and mesozooplankton in summer in this area is relatively large north of the SB-ACC but small south of the SB-ACC.
39
Horwitz, Pierre, e Mark Adams. "The systematics, biogeography and conservation status of species in the freshwater crayfish genus Engaewa Riek (Decapoda : Parastacidae) from south-western Australia". Invertebrate Systematics 14, n. 5 (2000): 655. http://dx.doi.org/10.1071/it99020.
Testo completoAbstract (sommario):
This paper presents a review of the systematics of freshwater crayfish species in the genus Engaewa Riek, endemic to south-western Australia. Allozyme electrophoresis of six allopatric populations of Engaewa and several outgroup taxa at 17 loci was initially used to identify four distinct genetic groups within the genus. Morphological characters were then used to establish within and between species boundaries more precisely. Five species were recognised, comprising the existing species E. subcoerulea Riek, E. reducta Riek, and E. similis Riek, plus two new species, E. pseudoreducta, sp. nov. and E. walpolea, sp. nov. The genus is endemic to south-western Australia where distributions of species conform to those expected for slowly dispersing, inland aquatic organisms wedded to year-round cool and wet conditions. The range of the genus occurs within the Warren Bioregion of Australia. The species occupy well-defined and largely non-overlapping geographical ranges. Within the bioregion, apparent incipient speciation exists in the Cape Naturaliste–Cape Leeuwin subregion, confirming a pattern observed for other aquatic organisms. Morphological and electrophoretic evidence suggests that species in the genus are more closely related to each other than they are to other species of extant freshwater crayfish, suggesting that they represent a monophyletic group. Nevertheless, the morphological variation displayed by Engaewa clearly falls within that found for the genus Engaeus Erichson from south-eastern Australia, indicating that a broad-scale generic revision for the entire group would be appropriate. The narrow geographical ranges of E. walpolea, sp. nov., E. pseudoreducta, sp. nov. and E. reducta, coupled with known threats to populations, warrant concern for these species from a conservation viewpoint. precisely.
40
Millar, AJK, e GT Kraft. "Catalogue of marine and freshwater red algae (Rhodophyta) of New South Wales, including Lord Howe Island, south-western Pacific". Australian Systematic Botany 6, n. 1 (1993): 1. http://dx.doi.org/10.1071/sb9930001.
Testo completoAbstract (sommario):
All published, and many unpublished, records of marine and freshwater red algae from the New South Wales mainland and Lord Howe Island are brought together for the first time. Of the 381 species listed (in 14 orders, 41 families and 174 genera), some 22% have New South Wales type localities (58 from the mainland and 24 from Lord Howe Island) and the remainder are either typically southern Australian, Queensland, or much more widely distributed. Twenty-five percent (100) of the species and 20% (35) of the genera are newly recorded for the New South Wales coast, one genus (Callithamniella) is new to the Pacific Ocean, and two (Ditria and Titanophora) are newly recorded for Australia. The new combination Gloiocladia minutula is also proposed. All nomenclature is updated and relevant synonyms and misapplied names are included.
41
Crook, David A., Paul Reich, Nick R. Bond, Damien McMaster, John D. Koehn e P. Sam Lake. "Using biological information to support proactive strategies for managing freshwater fish during drought". Marine and Freshwater Research 61, n. 3 (2010): 379. http://dx.doi.org/10.1071/mf09209.
Testo completoAbstract (sommario):
This paper provides an assessment of the biological attributes of fish species in south-eastern Australia and rates their potential risk from the impacts of drought. We used scientific literature and expert opinion to conduct a semiquantitative assessment of attributes considered to influence species resistance and resilience to drought for 15 freshwater fish species found in south-eastern Australia. We also present a conceptual framework to guide management of fish populations during drought. The framework focuses on (1) quantifying spatial variation in the severity of drought impacts on particular habitats (rivers, wetlands etc.), (2) assembling information on drought sensitivities of regionally important species, (3) identifying high risk areas (based on species sensitivity and drought severity), (4) determining and implementing appropriate management actions (pre-emptive, responsive), (5) monitoring outcomes and (6) disseminating information on outcomes. In many regions, historic population declines will serve to exacerbate the impacts of drought, and thus are a major threat to successful recovery from drought. Although we discuss both long-term, pre-emptive planning and short-term, responsive management actions, we contend that a long-term view is required to successfully address the threats posed by drought. Furthermore, although droughts clearly represent a severe disturbance to fish populations, ultimately it is anthropogenic factors that exacerbate drought and constrain recovery pathways (at global, regional and local scales), rather than drought per se. These factors must be addressed if we are to ensure the long-term viability of fish populations in inland aquatic ecosystems.
42
WILDE, G. R., e W. SAWYNOK. "Growth rate and mortality of Australian bass, Macquaria novemaculeata, in four freshwater impoundments in south-eastern Queensland, Australia". Fisheries Management and Ecology 12, n. 1 (febbraio 2005): 1–7. http://dx.doi.org/10.1111/j.1365-2400.2004.00412.x.
Testo completo
43
ROGERS, D. CHRISTOPHER. "Taxonomic certification versus the scientific method". Zootaxa 3257, n. 1 (4 aprile 2012): 66. http://dx.doi.org/10.11646/zootaxa.3257.1.5.
Testo completoAbstract (sommario):
Over the last 30 years or so there has been an increasing need for organism identification services. This has been the positive result of increased habitat monitoring, particularly as regards water quality. Organism diversity and community structure are used as an overall meter stick of habitat health and functionality, in a method referred to as biomonitoring. To meet the organism identification need, private and government laboratories specializing in identification work have been developed, particularly in North America, Europe and Australia. I myself have worked in this industry and was employed in either government or private laboratories over the last 18 years. These laboratories primarily identify benthic aquatic invertebrates, periphyton, phytoplankton, zooplankton and fish (both freshwater and marine).
44
PERKINS, ANDREW J. "Hydrocotyle simulans (Araliaceae), a new perennial species from south-eastern Australia". Phytotaxa 437, n. 2 (25 marzo 2020): 66–72. http://dx.doi.org/10.11646/phytotaxa.437.2.3.
Testo completoAbstract (sommario):
Hydrocotyle simulans, a new perennial species from south-eastern Australia, is here described with associated illustration, photographic images and distribution map. The new species is restricted mostly to freshwater swamps in coastal areas of south-eastern South Australia, southern Victoria and to the Furneaux Group of islands, off the north-eastern coast of Tasmania. Hydrocotyle simulans resembles both H. plebeya and H. pterocarpa, in having orbicular-cordate to reniform leaves, hydathodes along leaf lamina margins and broadly ovate to orbicular stipules with entire margins. It differs from these taxa by a combination of characters, such as reflexed white trichomes congregated at the petiole apices, ovate floral bracts with basal lobes, subsessile flowers with pale to dark crimson petals and lenticular mericarps with minutely rugulose surfaces when mature.
45
Sturm, K., Z. Yuan, B. Gibbes, U. Werner e A. Grinham. "Methane and nitrous oxide sources and emissions in a subtropical freshwater reservoir, South East Queensland, Australia". Biogeosciences 11, n. 18 (30 settembre 2014): 5245–58. http://dx.doi.org/10.5194/bg-11-5245-2014.
Testo completoAbstract (sommario):
Abstract. Reservoirs have been identified as an important source of non-carbon dioxide (CO2) greenhouse gases with wide ranging fluxes for reported methane (CH4); however, fluxes for nitrous oxide (N2O) are rarely quantified. This study investigates CH4 and N2O sources and emissions in a subtropical freshwater Gold Creek Reservoir, Australia, using a combination of water–air and sediment–water flux measurements and water column and pore water analyses. The reservoir was clearly a source of these gases as surface waters were supersaturated with CH4 and N2O. Atmospheric CH4 fluxes were dominated by ebullition (60 to 99%) relative to diffusive fluxes and ranged from 4.14 × 102 to 3.06 × 105 μmol CH4 m−2 day−1 across the sampling sites. Dissolved CH4 concentrations were highest in the anoxic water column and sediment pore waters (approximately 5 000 000% supersaturated). CH4 production rates of up to 3616 ± 395 μmol CH4 m−2 day−1 were found during sediment incubations in anoxic conditions. These findings are in contrast to N2O where no production was detected during sediment incubations and the highest dissolved N2O concentrations were found in the oxic water column which was 110 to 220% supersaturated with N2O. N2O fluxes to the atmosphere were primarily through the diffusive pathway, mainly driven by diffusive fluxes from the water column and by a minor contribution from sediment diffusion and ebullition. Results suggest that future studies of subtropical reservoirs should monitor CH4 fluxes with an appropriate spatial resolution to ensure capture of ebullition zones, whereas assessment of N2O fluxes should focus on the diffusive pathway.
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Sturm, K., Z. Yuan, B. Gibbes e A. Grinham. "Methane and nitrous oxide sources and emissions in a subtropical freshwater reservoir, south east Queensland, Australia". Biogeosciences Discussions 10, n. 12 (11 dicembre 2013): 19485–508. http://dx.doi.org/10.5194/bgd-10-19485-2013.
Testo completoAbstract (sommario):
Abstract. Reservoirs have been identified as an important source of non-CO2 greenhouse gases, especially methane (CH4). This study investigates CH4 and nitrous oxide (N2O) sources and emissions in a subtropical freshwater reservoir Gold Creek Dam, Australia using a combination of water–atmosphere and sediment–water flux measurements, water column sampling and pore water analysis. The reservoir was clearly a net source as surface waters were supersaturated with CH4 and N2O. CH4 flux rates were one to two orders of magnitude higher than N2O rates when expressed as CO2 equivalents. Atmospheric CH4 fluxes were dominated by ebullition (<60%) relative to diffusive fluxes and ranged from 165 to 6526 mg CO2 eq m−2 d−1. Dissolved CH4 concentrations in sediment pore waters were approximately 5 000 000% supersaturated. However, dissolved N2O concentrations were 140 to 220% supersaturated and generally confined to the water column greatly reducing the likelihood of ebullition. The flux measurements from this study support past findings that demonstrate the potential important contribution of emissions from subtropical reservoirs to overall GHG budgets. Results suggest future efforts to monitor and model emissions that concentrate on quantifying the ebullition pathway for CH4 as this was dominant relative to diffusive fluxes as well as total N2O emissions.
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Muhammad, Buhari Lawan, Yongsik Sin e Jang-Seu Ki. "DNA metabarcoding reveals multiple co-occurring species in Stephanodiscus spring diatom blooms in a temperate freshwater river". Marine and Freshwater Research 72, n. 9 (2021): 1353. http://dx.doi.org/10.1071/mf20254.
Testo completoAbstract (sommario):
Spring diatom blooms dominate the annual cycle of phytoplankton abundance in temperate freshwater systems. Many researchers have questioned whether severe blooms are attributable to a single species and warrant the identification of similar, concurrently occurring organisms. Here, we investigated spring diatom blooms in a temperate freshwater system (Yeongsan River, South Korea) that is thought to predominantly include the diatom Stephanodiscus hantzschii. Water samples were collected from four different sites during the blooms that occurred in March 2015. We analysed physicochemical and biological parameters and examined the species composition of the spring blooms using DNA metabarcoding via pyrosequencing. Our results revealed that several diatom species co-occurred during the blooms: Cyclotella sp. was the most frequently detected, followed by Cyclostephanos dubius and Discostella sp., whereas Stephanodiscus was only detected at two stations with low occurrence. These results suggest the coexistence of many diatoms during spring blooms in the Yeongsan River; however, Cyclotella sp. was responsible for the spring bloom attributed to S. hantzschii. DNA metabarcoding can be a useful tool for resolving species identities in spring diatom blooms in temperate freshwater systems. In addition, the co-occurrence of similar species should be considered when implementing efforts to monitor and control spring blooms.
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Pusey, BJ, e DHD Edward. "Structure of fish assemblages in waters of the Southern Acid Peat Flats, South-western Australia". Marine and Freshwater Research 41, n. 6 (1990): 721. http://dx.doi.org/10.1071/mf9900721.
Testo completoAbstract (sommario):
The structure of freshwater fish assemblages in waters of the southern acid peat flats of south-western Australia was monitored over a 3-year period. Nine locations were sampled during the course of the study; they differed in the permanence of the water supply and the degree of isolation from permanent water. The climate of the region is a Mediterranean one of high predictability (i.e. pronounced seasonality and low interannual variation). Consequently, temporary aquatic habitats were also temporally predictable in incidence and duration and were colonized by a comparatively rich fish fauna. Differences in habitat permanence and isolation were reflected in the structure of the fish assemblages, with temporary, highly isolated habitats being dominated by aestivating species. Temporary habitats not isolated from permanent water had the highest species richness and also contained one aestivating species. Permanent water habitats had the lowest species richness and diversity and were dominated by a single species (Edeba vittata). The assemblages changed little during the period of study with respect to species persistence and structure.
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Taylor, Graham, Francoise Gasse, P. H. Walker e P. J. Morgan. "The palaeoecological and palaeoclimatic significance of Miocene freshwater diatomite deposits from southern New South Wales, Australia". Palaeogeography, Palaeoclimatology, Palaeoecology 77, n. 2 (marzo 1990): 127–43. http://dx.doi.org/10.1016/0031-0182(90)90129-u.
Testo completo
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Crook, David A., Wayne M. Koster, Jed I. Macdonald, Simon J. Nicol, Chris A. Belcher, David R. Dawson, Damien J. O'Mahony, Danny Lovett, Adam Walker e Lucas Bannam. "Catadromous migrations by female tupong (Pseudaphritis urvillii) in coastal streams in Victoria, Australia". Marine and Freshwater Research 61, n. 4 (2010): 474. http://dx.doi.org/10.1071/mf09170.
Testo completoAbstract (sommario):
Understanding migratory requirements is critical for the conservation of diadromous fishes. Tupong (Pseudaphritis urvillii) are diadromous fishes found in freshwater and estuarine regions of south-eastern Australia. Previous studies have hypothesised that mature female tupong undertake downstream spawning migrations from freshwater to the estuary or sea, with a compensatory return of juveniles, and possibly spent fish, back upstream. We applied acoustic telemetry to test this hypothesis. We tagged 55 female tupong in two river systems in Victoria, Australia, and tracked movements for 4- to 6-month periods over 2 years. Thirty-one fish undertook rapid downstream migrations and then appeared to move through the estuary and out to sea between May and August in each year. Migration was associated with relatively high river discharges, and movement from the estuary to the sea tended to occur most frequently during intermediate moon phases. Low rates of movement between September and April suggested that tupong inhabited restricted home ranges outside of the spawning season. The apparently disparate migratory patterns of female (catadromous) and male (non-diadromous) tupong are rare amongst fishes globally. Differential exertion of a range of selective pressures may have resulted in the evolution of sexual differences in migratory modes in this species.