Brisbane River Research Articles

Comparison of pollution indices for the assessment of heavy metal in Brisbane River sediment

Estuarine environment is complex and receives different contaminants from numerous sources that are persistent, bioaccumulative and toxic. The distribution, source, contamination and ecological risk status of heavy metals in sediment of Brisbane River, Australia were investigated. Sediment samples were analysed for major and minor elements using LA-ICP-MS. Principal component analysis and cluster analysis identified three main sources of metals in the samples: marine sand intrusion, mixed lithogenic and sand intrusion as well as transport related. To overcome inherent deficiencies in using a single index, a range of sediment quality indices, including contamination factor, enrichment factor, index of geo-accumulation, modified degree of contamination, pollution index and modified pollution index were utilised to ascertain the sediment quality. Generally, the sediment is deemed to be “slightly” to “heavily” polluted. A further comparison with the Australian Sediment Quality Guidelines indicated that Ag, Cr, Cu, Ni, Pb and Zn had the potential to rarely cause biological effects while Hg could frequently cause biological effects. Application of potential ecological risk index (RI) revealed that the sediment poses moderate to considerable ecological risk. However, RI could not account for the complex sediment behaviour because it uses a simple contamination factor. Consequently, a modified ecological risk index (MRI) employing enrichment factor is proposed. This provides a more reliable understanding of whole sediment behaviour and classified the ecological risk of the sediment as moderate to very high. The results demonstrate the need for further investigation into heavy metal speciation and bioavailability in the sediment to ascertain the degree of toxicity.

Phylogeography of the Koala, (Phascolarctos cinereus), and Harmonising Data to Inform Conservation

The Australian continent exhibits complex biogeographic patterns but studies of the impacts of Pleistocene climatic oscillation on the mesic environments of the Southern Hemisphere are limited. The koala (Phascolarctos cinereus), one of Australia’s most iconic species, was historically widely distributed throughout much of eastern Australia but currently represents a complex conservation challenge. To better understand the challenges to koala genetic health, we assessed the phylogeographic history of the koala. Variation in the maternally inherited mitochondrial DNA (mtDNA) Control Region (CR) was examined in 662 koalas sampled throughout their distribution. In addition, koala CR haplotypes accessioned to Genbank were evaluated and consolidated. A total of 53 unique CR haplotypes have been isolated from koalas to date (including 15 haplotypes novel to this study). The relationships among koala CR haplotypes were indicative of a single Evolutionary Significant Unit and do not support the recognition of subspecies, but were separated into four weakly differentiated lineages which correspond to three geographic clusters: a central lineage, a southern lineage and two northern lineages co-occurring north of Brisbane. The three geographic clusters were separated by known Pleistocene biogeographic barriers: the Brisbane River Valley and Clarence River Valley, although there was evidence of mixing amongst clusters. While there is evidence for historical connectivity, current koala populations exhibit greater structure, suggesting habitat fragmentation may have restricted female-mediated gene flow. Since mtDNA data informs conservation planning, we provide a summary of existing CR haplotypes, standardise nomenclature and make recommendations for future studies to harmonise existing datasets. This holistic approach is critical to ensuring management is effective and small scale local population studies can be integrated into a wider species context.

Flood Inundation Modelling for Mid-Lower Brisbane Estuary

This study utilizes a two-dimensional hydrodynamic model to calibrate and validate an inundation model for the Brisbane River estuary in Queensland, Australia. The bathymetry data used in the hydraulic model are derived from one arc second (1 s) shuttle radar topography mission digital elevation model, and the two-dimensional hydraulic model is parameterized using the generated bathymetry with four open boundaries with water level observations and roughness coefficients. The calibration performance is evaluated by comparing the simulated results with the digitized records during the January 2013 flood event (a low magnitude event) at three gauging stations. The calibrated model is validated with water level data and available discharge data during the January 2011 flood (a large magnitude event) at four gauging stations located along the Brisbane River. Different performance indices are applied to demonstrate that the developed model performs well during calibration and validation. A sensitivity analysis is presented to assess the influence of riverbed elevation changes on the model because the main uncertainty of the model is the bathymetry data. The proposed model with the shuttle radar topography mission digital elevation model-derived riverbed elevation for the Brisbane estuary is able to predict the flood inundation extent at an accuracy of 66.9% which is higher than or comparable with the accuracies of the existing studies. However, it is expected that the accuracy will increase if some improved bathymetry data become available in the future. Copyright © 2016 John Wiley & Sons, Ltd.

The impact of a high magnitude flood on metal pollution in a shallow subtropical estuarine embayment

Drought-breaking floods pose a risk to coastal water quality as sediments, nutrients, and pollutants stored within catchments during periods of low flow are mobilized and delivered to coastal waters within a short period of time. Here we use subtidal surface sediment surveys and sediment cores to explore the effects of the 2011 Brisbane River flood on trace metals zinc (Zn), lead (Pb), copper (Cu), nickel (Ni), chromium (Cr), manganese (Mn), and phosphorus (P) deposition in Moreton Bay, a shallow subtropical bay in eastern Australia. Concentrations of Zn, Cu, and Pb in sediments in central Moreton Bay derived from the 2011 flood were the highest yet observed in the Bay. We suggest flushing of metal rich sediments which had accumulated on the Brisbane River floodplain and in its estuary during the preceding 10 to 40years of low flows to be the primary source of this increase. This highlights the importance of intermittent high magnitude floods in tidally influenced rivers in controlling metal transport to coastal waters in subtropical regions.

Applicability of pebble matrix filtration for the pre-treatment of surface waters containing high turbidity and NOM

Purification of drinking water is routinely achieved by use of conventional coagulants and disinfection procedures. However, there are instances such as flood events when the level of turbidity reaches extreme levels while natural organic matter (NOM) may be an issue throughout the year. Consequently, there is a need to develop technologies which can effectively treat water of high turbidity during flood events and NOM content year round. It was our hypothesis that pebble matrix filtration potentially offered a relatively cheap, simple and reliable means to clarify such challenging water samples. Therefore, a laboratory scale pebble matrix filter (PMF) column was used to evaluate the turbidity and NOM pre-treatment performance in relation to 2013 Brisbane River flood water. Since the high turbidity was only a seasonal and short-term problem, the general applicability of PMFs for NOM removal was also investigated. A 1.0-m-deep bed of pebbles (the matrix) partly infilled with either sand or crushed glass was tested, upon which was situated a layer of granular activated carbon. Turbidity was measured as a surrogate for suspended solids, whereas total organic carbon (TOC) and UV absorbance at 254nm were measured as surrogate parameters for NOM. Experiments using natural flood water showed that without the addition of any chemical coagulants, PMF columns achieved at least 50% turbidity reduction when the source water contained moderate hardness levels. For harder water samples, above 85% turbidity reduction was obtained. The ability to remove 50% turbidity without chemical coagulants may represent significant cost savings to water treatment plants and added environmental benefits accrue due to less sludge formation. A TOC reduction of 35–47% and UV-254nm reduction of 24–38% were also observed. In addition to turbidity removal during flood periods, the ability to remove NOM using the PMF throughout the year may have the benefit of reducing disinfection by-products formation potential and coagulant demand at water treatment plants. Final head losses were remarkably low, reaching only 11 cm at a filtration velocity of 0.70 m/h.

Bigger clutch sizes save offspring energy during nest escapes

Hatchling turtles typically emerge from underground nests in groups, so the nest escape process may represent another example of animals sharing a task (in this case, digging out of a nest) to save on individual energy expenditure. Previous studies have reported the energetic cost of embryonic development across chelonian taxa, but none has quantified the extra amount of energy needed to escape the nest. Brisbane river turtle (Emydura macquarii signata) hatchlings were found to fuel this activity by using approximately 50 % of their residual yolk energy content. An open-flow respirometry system was used to quantify the effect of clutch size on an individual’s energetic cost while digging out of the nest. The energetic cost of nest escaping 15 cm upward in the fine moist sand was calculated to be between 0.34 and 2.32 kJ per individual depending upon the number of hatchlings digging together. The energetic cost decreased as the number of individuals digging together increased and thus supports the ‘social facilitation’ hypothesis which suggests hatchlings cooperate to share the workload of digging out of the nest amongst clutch mates to reduce individual energy expenditure. The reduced energetic cost associated with large cohorts was chiefly caused by the shorter time taken to dig out of the nest by larger numbers of individuals. We conclude that synchronous digging activity of many individuals during nest escape evolved not only to facilitate quicker nest emergence but also reduce the energetic cost to individuals.

Water isotope characteristics of a flood: Brisbane River, Australia

AbstractFlooding associated with tropical storms can cause extreme perturbations in riverine and coastal ecosystems. Measuring isotope variability of tropical storm events can help investigate the impacts of flooding. We measured the water isotope composition (δD and δ18O) of rain and associated floodwater collected during two storms and subsequent major and minor flooding events in the subtropical coast of eastern Australia. Compared with baseline regional rainfall isotope values of −15.0 ± 1.9‰ for δD and −3.3 ± 0.2‰ for δ18O, floodwater had lower values with −33.8 ± 2.5‰ δD and −5.1 ± 0.4‰ δ18O for the major flood and −29.4 ± 1.0‰ δD and −4.6 ± 0.1‰ δ18O for the minor flood. The low isotope composition of the floodwater was associated with the transport of large quantities of suspended sediments, with sediment loads 30 to 70 times larger than during base flow conditions. Floods carried up to 35% of the annual phosphorus and up to 208% of the currently calculated average annual nitrogen load of the Brisbane River. The dramatic changes caused by a rapid increase in discharge from 2 to 2015 m3 s−1 over 2 days in the major flood would have major consequences in riverine and coastal ecosystems of the region. These changes could potentially be traced using the isotope composition of the floodwaters. Copyright © 2015 John Wiley & Sons, Ltd.

The role of urban planning and design in responding to climate change: the Brisbane experience

Purpose – The purpose of this paper is to discuss the responses from the urban planning and design professions in Brisbane to the impacts of climate change and the implications of the 2011 flood. In the past decade, the ramifications of climate change have already left a scar on some of the urban regions round the world. The Australian continent has been regarded as one of the most affected regions in terms of climate change implications. The 2011 Queensland floods of historic proportion, which came after a decade of extreme drought, raised many questions about the future development of cities. For the past decades, Queensland’s economy was largely based on property-led development. The flood plain land situated along Brisbane River has been developed and overburdened with building infrastructure contributing to the magnification of the flood events. Design/methodology/approach – The research methodology is based on identification of the problem and the major objective. To address the objective, this study concentrated mainly on the use of qualitative research methods. The major qualitative research methods include literature review, qualitative analysis and observations. Brisbane, the capital of the Australian state of Queensland, has been selected as the case study area. Findings – The paper revealed strong regional and city-wide planning directives addressing climate change which has not yet been fully been translated at the local-neighbourhood level. Originality/value – This paper provides a deep insight analysis and evaluation of the design and planning measures currently used to combat the impacts of climate change.

Sources and sinks of methane and nitrous oxide in the subtropical Brisbane River estuary, South East Queensland, Australia

This study investigated sources and sinks of methane (CH4) and nitrous oxide (N2O) in the Brisbane River estuary, Australia. Field measurements and laboratory incubation experiments were performed to determine the contribution of the water column, sediments, influent creeks and discharge from a wastewater treatment plant, to greenhouse gas levels occurring in the estuary. Sampling was conducted at 16 sites along the estuary with more detailed studies at three of these sites, located in the lower, middle and upper estuarine reaches, respectively. The estuary is a source of CH4 and N2O with their saturation in the surface water ranging between 2160 and 26,900% for CH4, and between 140 and 230% for N2O, relative to their respective atmospheric concentrations. Estuarine sediments were identified as sources for both CH4 and N2O, as concentrations for both dissolved gases were higher in the pore water at the sediment surfaces in comparison to the water column samples at all sites. Methane and N2O were produced in silty sediments as shown in sediment-water incubations. Creeks were detected to be a source of CH4 and N2O, as their concentrations were higher in the creek in comparison to those measured at the confluence of the creek and the estuary. The estuarine water column was identified as a CH4 sink; however, the water column was neither a sink nor a source for N2O. A wastewater treatment plant discharging effluent into the tributary did not contribute significantly to the creek CH4 levels, but may have elevated N2O at the direct point of discharge. A budget estimate of the Brisbane River estuary showed that sediments are not the sole source of CH4, as the sediment-water fluxes are far less (1%) than what is consumed, emitted or transported to the ocean. An unknown CH4 source is therefore likely present, which is yet to be revealed. In contrast, most of N2O produced in the estuarine sediments was emitted to the atmosphere.

Utility of Helicobacter spp. associated GFD markers for detecting avian fecal pollution in natural waters of two continents

Avian fecal droppings may negatively impact environmental water quality due to the presence of high concentrations of fecal indicator bacteria (FIB) and zoonotic pathogens. This study was aimed at evaluating the performance characteristics and utility of a Helicobacter spp. associated GFD marker by screening 265 fecal and wastewater samples from a range of avian and non-avian host groups from two continents (Brisbane, Australia and Florida, USA). The host-prevalence and -specificity of this marker among fecal and wastewater samples tested from Brisbane were 0.58 and 0.94 (maximum value of 1.00). These values for the Florida fecal samples were 0.30 (host-prevalence) and 1.00 (host-specificity). The concentrations of the GFD markers in avian and non-avian fecal nucleic acid samples were measured at a test concentration of 10 ng of nucleic acid at Brisbane and Florida laboratories using the quantitative PCR (qPCR) assay. The mean concentrations of the GFD marker in avian fecal nucleic acid samples (5.2 × 103 gene copies) were two orders of magnitude higher than non-avian fecal nucleic acid samples (8.6 × 101 gene copies). The utility of this marker was evaluated by testing water samples from the Brisbane River, Brisbane and a freshwater creek in Florida. Among the 18 water samples tested from the Brisbane River, 83% (n = 18) were positive for the GFD marker, and the concentrations ranged from 6.0 × 101–3.2 × 102 gene copies per 100 mL water. In all, 92% (n = 25) water samples from the freshwater creek in Florida were also positive for the GFD marker with concentrations ranging from 2.8 × 101–1.3 × 104 gene copies per 100 mL water. Based on the results, it can be concluded that the GFD marker is highly specific to avian host groups, and could be used as a reliable marker to detect the presence and amount of avian fecal pollution in environmental waters.

Brisbane City Council's Q100 assessment: How climate risk management becomes scientised

This paper provides a report of climate risk management for the city of Brisbane between 1976 and 2011. Using the evidence presented by the Commission of Inquiry established to investigate extreme flooding events across Queensland in 2010–2011, this paper describes Brisbane City Council’s ongoing attempts to derive a ‘Q100’ flood risk management metric as a means to determine urban planning policy. The evidence presented by the Commission demonstrates how the normative decisions that underpinned the Council’s derivation of Q100 and which sought to maximise urban development in the Brisbane River floodplain were in direct conflict with State government's concurrent priorities relating to water resources supply and flood risk management. This account of conflicting climate risk management strategies by local and state government demonstrates how the derivation of technical expert evidence can become politicised to align with conflicting priorities, and are then used in a ‘scientised’ environmental planning process.

Morphological and molecular data for three species of the Microphallidae (Trematoda: Digenea) in Australia, including the first descriptions of the cercariae of Maritrema brevisacciferum Shimazu et Pearson, 1991 and Microphallus minutus Johnston, 1948.

Cercariae and metacercariae of three species of the Microphallidae Travassos, 1920 were found in snails and crustaceans from tributaries of the Brisbane River, Queensland, Australia. Specimens of Maritrema brevisacciferum Shimazu et Pearson, 1991 and Microphallus minutus Johnston, 1948, which have previously been reported in Queensland, were found as cercariae in the tateid gastropod Posticobia brazieri (Smith) and as metacercariae of M. brevisacciferum in the atyid shrimp Caridina indistincta Calman and of M. minutus in the parastacid crayfish Cherax dispar Reik. Combined analysis of morphological and molecular data, based on newly generated ITS2 and partial 28S rDNA data, linked cercariae and metacercariae for both species. This is the first report of the first intermediate hosts of M. brevisacciferum and M. minutus. Infections of another unidentified microphallid metacercariae, Microphallidae gen. sp., were found in P. brazieri and C. indistincta. The sequences of metacercarial isolates from both hosts were identical. The data on the Microphallidae from Australia and species that develop in freshwater invertebrates were examined in detail.

River response to European settlement in the subtropical Brisbane River, Australia

Abstract The response of river channels to land cover and land use changes in large areas of the tropics and subtropics is poorly documented. Arable agriculture and grazing was introduced to the subtropical catchment of the Brisbane River, Australia, by European settlers in the 1840s. This study examines subsequent changes to the morphology, sediments and vegetation of the Brisbane River in relation to the major drivers of channel change. Documentary evidence from pioneers, paintings, newspapers,maps, surveys, photographs, and instrumental flow records suggests that within 20 years of the introduction of sheep grazing, compaction and degradation of catchment soils and surface drainage produced a shift from perennial to seasonally ephemeral flow and channel incision in minor tributary valleys. The main channel remained stable until the 1850s in the Estuary, and until the 1890s in the middle reaches, where bank erosion increased average channel widths by 18%. Compared to rivers in temperate areas, the Brisbane River has been relatively resilient to changes in land use and land cover. Rates of lateral channel migration have been low since at least 1885, and the level of the channel bed has been stable since 1894. It is shown that the present-day compound channel is a pre-European form with dimensions adjusted to floods with decadal return periods. Increases in sediment supply associated with the incision of tributary streams and later, from widening of the main channel, is consistent with regional evidence for the predominance of channel erosion. This implies an ongoing channel adjustment to changes associated with European land use change.

Toolbox Approaches Using Molecular Markers and 16S rRNA Gene Amplicon Data Sets for Identification of Fecal Pollution in Surface Water.

In this study, host-associated molecular markers and bacterial 16S rRNA gene community analysis using high-throughput sequencing were used to identify the sources of fecal pollution in environmental waters in Brisbane, Australia. A total of 92 fecal and composite wastewater samples were collected from different host groups (cat, cattle, dog, horse, human, and kangaroo), and 18 water samples were collected from six sites (BR1 to BR6) along the Brisbane River in Queensland, Australia. Bacterial communities in the fecal, wastewater, and river water samples were sequenced. Water samples were also tested for the presence of bird-associated (GFD), cattle-associated (CowM3), horse-associated, and human-associated (HF183) molecular markers, to provide multiple lines of evidence regarding the possible presence of fecal pollution associated with specific hosts. Among the 18 water samples tested, 83%, 33%, 17%, and 17% were real-time PCR positive for the GFD, HF183, CowM3, and horse markers, respectively. Among the potential sources of fecal pollution in water samples from the river, DNA sequencing tended to show relatively small contributions from wastewater treatment plants (up to 13% of sequence reads). Contributions from other animal sources were rarely detected and were very small (<3% of sequence reads). Source contributions determined via sequence analysis versus detection of molecular markers showed variable agreement. A lack of relationships among fecal indicator bacteria, host-associated molecular markers, and 16S rRNA gene community analysis data was also observed. Nonetheless, we show that bacterial community and host-associated molecular marker analyses can be combined to identify potential sources of fecal pollution in an urban river. This study is a proof of concept, and based on the results, we recommend using bacterial community analysis (where possible) along with PCR detection or quantification of host-associated molecular markers to provide information on the sources of fecal pollution in waterways.

Relationships between pollutant discharge and water quality in the rivers from “better” to “worse” water quality

The long-term relationship between pollutant discharge and river water quality of biological/biochemical oxygen demand (BOD) in the Yamato-gawa River, Japan, has been found to be similar to perturbation or dynamic equilibrium change of alternative stable states in the ecosystem fields with a linear relationship as a usual condition. Similar relationships have been observed in short-terms for single precipitation events both in the Richmond River, Australia, and in a mountainous watershed in Japan. On the contrary, nutrient concentrations have not changed in a long-term besides nutrient discharge increases in the Richmond River. In this paper, long-term chronological relationships of annual pollutant discharges and water quality in the Brisbane River, Australia, were investigated based on pollutant discharge estimations and water quality monitoring data as a case study in the “better” water quality river. Effects of precipitation variation were taken into account in the pollutant discharge estimations by introducing precipitation variance coefficient (PVC). Total nitrogen (TN) and total phosphorus (TP) concentrations in the river were found to be improved with fluctuations in the lower Brisbane River Catchment during 1975–2012. Long-term dynamic equilibrium alterations of pollutant discharge and water quality were found for TN and TP at the first time in the Brisbane River. The investigated term was found to be divided into two phases, 1975–2001 and 2001–2012 for TN, and 1975–2007 and 2005–2012 for TP. Both pollutant discharges and pollutant concentrations in the river were smaller in Phase 2 than Phase 1. Based on the relationships in the three rivers, a hypothesis on pollutant discharge and water quality from “better” to “worse” river water environment was presented that rapid and/or excess pollutant discharge increases cause perturbation or dynamic equilibrium alterations with the basal relationships as the linear relationships.

Morphology of the ampullae of Lorenzini in juvenile freshwater Carcharhinus leucas.

Ampullae of Lorenzini were examined from juvenile Carcharhinus leucas (831-1,045 mm total length) captured from freshwater regions of the Brisbane River. The ampullary organ structure differs from all other previously described ampullae in the canal wall structure, the general shape of the ampullary canal, and the apically nucleated supportive cells. Ampullary pores of 140-205 µm in diameter are distributed over the surface of the head region with 2,681 and 2,913 pores present in two sharks that were studied in detail. The primary variation of the ampullary organs appears in the canal epithelial cells which occur as either flattened squamous epithelial cells or a second form of pseudostratified contour-ridged epithelial cells; both cell types appear to release material into the ampullary lumen. Secondarily, this ampullary canal varies due to involuted walls that form a clover-like canal wall structure. At the proximal end of the canal, contour-ridged cells abut a narrow region of cuboidal epithelial cells that verge on the constant, six alveolar sacs of the ampulla. The alveolar sacs contain numerous receptor and supportive cells bound by tight junctions and desmosomes. Pear-shaped receptor cells that possess a single apical kinocilium are connected basally by unmyelinated neural boutons. Opposed to previously described ampullae of Lorenzini, the supportive cells have an apical nucleus, possess a low number of microvilli, and form a unique, jagged alveolar wall. A centrally positioned centrum cap of cuboidal epithelial cells overlies a primary afferent lateral line nerve.

Salinity and turbidity distributions in the Brisbane River estuary, Australia

Summary The Brisbane River estuary (BRE) in Australia not only plays a vital role in ecosystem health, but is also of importance for people who live nearby. Comprehensive investigations, both in the short- and long-term, into the salinity and turbidity distributions in the BRE were conducted. Firstly, the analysis of numerical results revealed that the longitudinal salinity varied at approximately 0.45 and 0.61 psu/h during neap and spring tides, respectively. The turbidity stayed at a higher level and was less impacted by tide in the upper estuary, however, the water cleared up while the tide changed from flood to ebb in the mid and lower estuary. The second investigation into the seasonal variations of salinity and turbidity in the BRE was conducted, using ten-year field measurement data. A fourth-order polynomial equation was proposed, describing the longitudinal variation in salinity dilution changes as the upstream distance in the BRE during the wet and dry seasons. From the observation, the mid and upper estuaries were vertically well-mixed during both seasons, but the lower BRE was stratified, particularly during the wet season. The estuary turbidity maximum (ETM) zone was about 10 km longer during the wet season than the dry season. Particular emphasis was given to the third investigation into the use of satellite remote sensing techniques for estimation of the turbidity level in the BRE. A linear relationship between satellite observed water reflectance and surface turbidity level in the BRE was validated with an R 2 of 0.75. The application of satellite-observed water reflectance therefore provided a practical solution for estimating surface turbidity levels of estuarine rivers not only under normal weather conditions, but also during flood events. The results acquired from this study are valuable for further hydrological research in the BRE and particularly prominent for immediate assessment of flood impacts.

Impact of an extreme flood event on optical and biogeochemical properties in a subtropical coastal periurban embayment (Eastern Australia)

AbstractMajor floods impacted the city of Brisbane, eastern Australia, in January 2011, delivering large amounts of dissolved and particulate materials and nutrients into the adjacent coastal embayment, Moreton Bay. The resulting spatially resolved changes in biogeochemical and optical properties in Moreton Bay were examined 1, 2, 6, 19, and 49 weeks after the main freshwater discharge. One week postflood, total suspended matter (TSM) and chlorophyll a (TChla) concentrations varied over 1 order of magnitude throughout Moreton Bay, the particle scattering coefficient at 555 nm varied by a factor of 20, and the total absorption coefficient and colored dissolved organic matter (CDOM) absorption coefficient at 440 nm varied by a factor of 5. The largest changes in biogeochemical and optical properties observed during our study were from 1 to 2 weeks after the floods: near the Brisbane River mouth, TSM decreased by a factor of 3, CDOM by a factor of 2, while TChla increased by a factor of 3. Within a year, optical and biogeochemical properties recovered to levels similar to nonflood conditions. The strong changes in the characteristics of the particulate and dissolved material following the flood event and subsequent biological and photochemical processes led to a large spatial and temporal variability in the relative contribution of different constituents to the total absorption coefficient at 440 nm, the particle single scattering albedo, and the specific inherent optical properties. This work has significant implications for the accuracy of standard ocean color remote sensing algorithms in coastal waters during flood events.

Occurrence of lungfish in the Brisbane River, Queensland, Australia dates back to 3850 yr BP

Bone fragments collected from the Platypus RockShelter in southeast Queensland, on the banks of the Brisbane River, can be compared with bone from the living Australian lungfish, Neoceratodus forsteri, and suggest that this species, which was widely distributed in Queensland in Pliocene and Pleistocene deposits, was also found in the Brisbane River as recently as 3850 years before the present, based on current 14C dates. The fragments have dimensions and morphology consistent with parts of lungfish jaws and palatal bones, and differ from the bones of teleost fish of comparable size that live in the Brisbane River. Unfortunately, attempts to extract mitochondrial DNA from the bones have not been successful due to very low levels of endogenous DNA. The presence of morphologically identifiable lungfish bones suggests that the Brisbane River has, and always did have, a population of lungfish that belong in this river and were not translocated. The Brisbane River is separated from the Mary and Burnett Rivers by mountain ranges, and the Rockshelter is 90 km away from the nearest tributary of the Mary River. Using a morphological analysis of carbon-dated midden site skeletal material, we show that lungfish were present in the Brisbane River over three thousand years ago, and may always have been there, despite attempts to translocate lungfish to this habitat. This finding is significant because lungfish are now seriously at risk in all of their present habitats from human interference in the environment and the resulting loss of biodiversity. Confirmation that the Brisbane River contains a population of lungfish, and always has done, increases the need for protection of this endangered species.

Spatio-temporal assessment of perfluorinated compounds in the Brisbane River system, Australia: Impact of a major flood event

Perfluorinated chemicals including PFOA and PFOS have been widely used in consumer products and have become ubiquitous pollutants widely distributed in the aqueous environment. Following a major flood event in 2011, water samples were collected along a spatial gradient of the Brisbane River system to provide an initial estimate of the release of PFASs from flooded urban areas. PFOA (mean concentrations 0.13–6.1ngL−1) and PFOS (mean concentrations 0.18–15ngL−1) were the most frequently detected and abundant PFASs. Mean total PFASs concentrations increased from 0.83ngL−1 at the upstream Wivenhoe Dam to 40ngL−1 at Oxley Creek, representing an urban catchment. Total masses of PFOA and PFOS delivered into Moreton Bay from January to March were estimated to be 5.6kg and 12kg respectively. From this study, urban floodwaters appear to be a previously overlooked source of PFASs into the surrounding environment.