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Hexa(methoxymethyl)melamine (HMMM) is commonly used as a cross-linking agent in coatings and as a vulcaniser in tyre production to increase the durability of tyres. Early reports of elevated aquatic concentrations of HMMM and a range of co-occurring cyclic amines have been linked to toxicity and mortality events of aquatic organisms. There are currently only few studies reporting environmental concentrations of HMMM and the co-occurring cyclic amines, and this study reports the first environmental assessment in Australian surface waters. Archive passive water samples from 40 rivers, creeks and lakes in South East Queensland, Australia, and covering five years of biannual sampling, were analysed to determine spatial and temporal trends. Concentrations of HMMM and cyclic amines in Australian surface waters (5-46 andMDL-280 ng/L respectively) were towards the low end of concentrations reported in surface water in North America/Europe. While previous studies have indicated that HMMM can be used as an indicator chemical of tyre wear particle inputs from stormwater runoff to a water system, the variable spatial and temporal trends at these sites indicates there are a range of different sources, and more research is needed into these chemicals to understand their occurrence in the environment.

Animal faecal contamination of surface waters poses a human health risk, as they may contain pathogenic bacteria or viruses. Of the numerous animal species residing along surface waterways in Australia, macropod species are a top contributor to wild animals’ faecal pollution load. We characterised the gut microbiota of 30 native Australian Eastern Grey Kangaroos from six geographical regions (five kangaroos from each region) within South East Queensland in order to establish their bacterial diversity and identify potential novel species-specific bacteria for the rapid detection of faecal contamination of surface waters by these animals. Using three hypervariable regions (HVRs) of the 16S rRNA gene (i.e., V1–V3, V3–V4, and V5–V6), for their effectiveness in delineating the gut microbial diversity, faecal samples from each region were pooled and microbial genomic DNA was extracted, sequenced, and analysed. Results indicated that V1-V3 yielded a higher taxa richness due to its larger target region (~480 bp), however, higher levels of unassigned taxa were observed using the V1-V3 region. In contrast, the V3–V4 HVR (~569 bp) attained a higher likelihood of a taxonomic hit identity to the bacterial species level, with a 5-fold decrease in unassigned taxa. There were distinct dissimilarities in beta diversity between the regions, with the V1-V3 region displaying the highest number of unique taxa (n = 42), followed by V3–V4 (n = 11) and V5–V6 (n = 8). Variations in the gut microbial diversity profiles of kangaroos from different regions were also observed, which indicates that environmental factors may impact the microbial development and, thus, the composition of the gut microbiome of these animals.

The management of inland waterways to protect recreational users from cyanotoxin exposure is complicated by the common management practice of using proxy indicators of cyanotoxin production (cell counts and biovolumes of potentially toxin species), rather than the cyanotoxin itself. This widely accepted practice is further complicated by a lack of advisory guidelines for non-microcystin-producing cyanotoxins. This study has investigated the effectiveness of this management approach over five and a half years, monitoring 65 different sites in South East Queensland using phycological and toxin-analysis. This study concluded that cell counts of Cylindrospermopsis raciborskii, the most common potentially toxin producing species of cyanobacteria in South East Queensland's inland lakes, was a poor proxy indicator for cylindrospermopsin toxin production. Seqwater, the local water authority responsible for the management of recreational access to drinking water storage lakes, initiated an alternative management approach for recreational cyanobacterial water quality management in December 2016. This new approach is based on cyanobacterial toxin guideline values for five different cyanotoxins, with closures and warning notices issued based on the actual cyanotoxin concentration, not the proxy indicator. We encourage other recreational water management authorities consider this approach to manage recreational access in the future.

Characterization of microbial communities using high-throughput amplicon sequencing is an emerging approach for microbial source tracking of fecal pollution. This study used SourceTracker software to examine temporal and geographical variability of fecal bacterial community profiles to identify pollutant sources in three freshwater catchments in sub-tropical Australia. Fecal bacterial communities from 10 animal species, humans, and composite wastewater samples from six sewage treatment plants were characterized and compared to freshwater samples using Illumina amplicon sequencing of the V5–V6 regions of the 16S rRNA gene. Source contributions were calculated in SourceTracker using new fecal taxon libraries as well as previously generated libraries to determine the effects of geographic and temporal variability on source assignments. SourceTracker determined 16S rRNA bacterial communites within freshwater samples, shared taxonomic similarities to that of wastewater at low levels (typically

Enteric pathogens can be present in drinking water catchments due to several point and non-point sources of faecal contamination. Pathogen and contaminant signatures will decay due to environmental stresses, such as temperature, Ultra Violet (UV) radiation, salinity, and predation. In this study, we determined the decay of the culturable faecal indicator bacterium (FIB) Escherichia coli (E. coli), two sewage-associated marker genes (Bacteroides HF183 and crAssphage CPQ_056), and enteric pathogens (Campylobacter spp., human adenovirus 40/41, and Cryptosporidium parvum) in two freshwater laboratory microcosms using culture-based, quantitative PCR (qPCR) and vital dye (determine the fraction of viable Cryptosporidium oocysts) assays. Freshwater samples from the Lake Wappa and Lake Wivenhoe (Australia) were seeded with untreated sewage and C. parvum oocysts, and their declining concentrations were measured over a 28-day period. Moreover, 16S rRNA amplicon sequencing was also undertaken to determine the change/shift in sewage-associated bacterial communities using SourceTracker. Overall, culturable E. coli and the HF183 marker gene decayed significantly (p 0.05) faster than did the qPCR measured enteric pathogens suggesting that the absence of culturable FIB or qPCR HF183 in water samples may not indicate the absence of pathogens. The decay of crAssphage was similar to that of HAdV 40/41 and other pathogens tested, suggesting crAssphage may be a better surrogate for enteric viruses in sub-tropical catchment waters. The decay rates were greater at 25 °C compared to 15 °C, suggesting that FIB and pathogens persist longer in the winter season compared to summer. Overall decay rates of the tested microorganisms in this microcosm study suggest that sub-tropical conditions, especially temperature, have a negative impact on the persistence of tested microorganisms. Sewage-associated bacterial communities also showed similar patterns. Based on the results, which showed differences in simulated summer and winter temperatures for pathogen decay, corresponding management options and treatment need to be adjusted accordingly to minimize human health risks effectively.

A regression model integrating data pre-processing and transformation, input selection techniques and a data-driven statistical model, facilitated accurate 7 day ahead time series forecasting of selected water quality parameters. A core feature of the modelling approach is a novel recursive input–output algorithm. The herein described model development procedure was applied to the case of a 7 day ahead dissolved oxygen (DO) concentration forecast for the upper hypolimnion of Advancetown Lake, Queensland, Australia. The DO was predicted with an R2 > 0.8 and a normalised root mean squared error of 14.9% on a validation data set by using 10 inputs related to water temperature or pH. A key feature of the model is that it can handle nonlinear correlations, which was essential for this environmental forecasting problem. The pre-processing of the data revealed some relevant inputs that had only 6 days' lag, and as a consequence, those predictors were in-turn forecasted 1 day ahead using the same procedure. In this way, the targeted prediction horizon (i.e. 7 days) was preserved. The implemented approach can be applied to a wide range of time-series forecasting problems in the complex hydro-environment research area. The reliable DO forecasting tool can be used by reservoir operators to achieve more proactive and reliable water treatment management.

The measurement of coral surface area is critical to normalising a suit of physiologically significant parameters to greater understand how corals interact with the surrounding environment. The surface area detection from skeletal fragments subsequently needs to be both as accurate as possible, yet practical and robust enough to be performed with minimal laboratory equipment. By using X-Ray CT technology, as a highly accurate surface area standard, 12 coral specimens from 4 different genera were studied using single wax versus double wax dipping methods. Our results reveal that the single wax dipping is far more accurate than the more commonly practised double wax dipping, thereby leading to more accurate estimation of the physiologically active surface.

The three-dimensional morphology and surface area of organisms such as reef-building corals is central to their biology. Consequently, being able to detect and measure this aspect of corals is critical to understanding their interactions with the surrounding environment. This study explores six different methods of three-dimensional shape and surface area measurements using the range of morphology associated with the Scleractinian corals: Goniopora tenuidens, Acropora intermedia, and Porites cylindrica. Wax dipping; foil wrapping; multi-station convergent photogrammetry that used the naturally occurring optical texture for conjugate point matching; stereo photogrammetry that used projected light to provide optical texture; a handheld laser scanner that employed two cameras and a structured light source; and X-ray computer tomography (CT) scanning were applied to each coral skeleton to determine the spatial resolution of surface detection as well as the accuracy of surface area estimate of each method. Compared with X-ray CT, wax dipping provided the best estimate of the surface area of coral skeletons that had external corallites, regardless of morphological complexity. Foil wrapping consistently showed a large degree of error on all coral morphologies. The photogrammetry and laserscanning solutions were effective only on corals with simple morphologies. The two techniques that used projected lighting were both subject to skeletal light scattering, caused by both gross morphology and meso-coral architecture and which degraded signal triangulation, but otherwise provided solutions with good spatial resolution. X-ray CT scanning provided the highest resolution surface area estimates, detecting surface features smaller than 1000 im2.

SUMMARY Wave lensing produces the highest level of transient solar irradiances found in nature, ranging in intensity over several orders of magnitude in just a few tens of milliseconds. Shallow coral reefs can be exposed to wave lensing during light-wind, clear-sky conditions, which have been implicated as a secondary cause of mass coral bleaching through light stress. Management strategies to protect small areas of high-value reef from wave-lensed light stress were tested using seawater irrigation sprinklers to negate wave lensing by breaking up the water surface. A series of field and tank experiments investigated the physical and photophysiological response of the shallow-water species Stylophora pistillata and Favites abdita to wave lensing and sprinkler conditions. Results show that the sprinkler treatment only slightly reduces the total downwelling photosynthetically active and ultraviolet irradiance (∼5.0%), whereas it dramatically reduces, by 460%, the irradiance variability caused by wave lensing. Despite this large reduction in variability and modest reduction in downwelling irradiance, there was no detectable difference in photophysiological response of the corals between control and sprinkler treatments under two thermal regimes of ambient (27°C) and heated treatment (31°C). This study suggests that shallow-water coral species are not negatively affected by the strong flashes that occur under wave-lensing conditions.

SUMMARY Depth zonation on coral reefs is largely driven by the amount of downwelling, photosynthetically active radiation (PAR) that is absorbed by the symbiotic algae (zooxanthellae) of corals. The minimum light requirements of zooxanthellae are related to both the total intensity of downwelling PAR and the spectral quality of the light. Here we used Stylophora pistillata colonies collected from shallow (3 m) and deep (40 m) water; colonies were placed in a respirometer under both ambient PAR irradiance and a filter that only transmits blue light. We found that the colonies exhibited a clear difference in their photosynthetic rates when illuminated under PAR and filtered blue light, with higher photosynthetic performance when deep colonies were exposed to blue light compared with full-spectrum PAR for the same light intensity and duration. By contrast, colonies from shallow water showed the opposite trend, with higher photosynthetic performances under full-spectrum PAR than under filtered blue light. These findings are supported by the absorption spectra of corals, with deeper colonies absorbing higher energy wavelengths than the shallow colonies, with different spectral signatures. Our results indicate that S. pistillata colonies are chromatically adapted to their surrounding light environment, with photoacclimation probably occurring via an increase in photosynthetic pigments rather than algal density. The spectral properties of the downwelling light are clearly a crucial component of photoacclimation that should be considered in future transplantation and photoacclimation studies.

Variation in subsurface solar radiation has been identified as a second-order factor in coral bleaching. This study examines transmission of radiation at Heron Reef (southern Great Barrier Reef, Australia) testing the hypotheses that spectral transmission is independent of location, season and solar zenith angle. In June and December 2004, 132 underwater irradiance profiles were collected at six ultraviolet wavelengths (305, 313, 320, 340, 380, 395 nm) and photosynthetically-active radiation (PAR) to estimate spectral diffuse attenuation coefficients Kd(λ). Mean Kd(λ) decreased through the ultraviolet spectrum (0.435 m–1 at 305 nm to 0.115 m–1 at 395 nm) whereas mean Kd(PAR) was 0.129 m–1. Ultraviolet Kd(λ) values were highly correlated with each other, but less well correlated with Kd(PAR). Kd(λ) values were larger inside than outside Heron Lagoon, both across all wavelengths and at individual wavelengths. Similarly, Kd(λ) values were significantly larger in December than June. These results are consistent with greater resuspension and transport of particulates in Heron Lagoon at higher wind speeds. Kd(λ) values were not dependent on solar zenith angle. The implications are that location and season must be accounted for when setting Kd(λ) values to calculate spectral irradiances affecting corals at Heron Reef.

In optically shallow waters of coral reefs, the contribution of both direct and diffuse ultraviolet irradiance is poorly documented yet its involvement in biological processes is highly significant. Here we present a new approach of partitioning the ultraviolet attenuation coefficient into direct and diffuse components in the top 5 m of waters surrounding Heron Reef, Queensland, Australia (23°27′S, 151°55′E), during the austral summer solstice from 11 to 21 December 2005. A commercial ultraviolet radiometer, which operated in selected spectral bands centred at 305, 313, 320, 340, 380 and 395 nm, was fitted with an aquatic shadow-band that allowed the measurement of both global and diffuse irradiances. Direct irradiance was estimated by subtracting diffuse irradiance from global irradiance. Results revealed that direct irradiance was attenuated more quickly than diffuse irradiance, with stronger attenuation in the shorter wavelengths. Attenuation coefficients for the global, diffuse and direct components of irradiance were significantly different, justifying their separate treatment through partitioning. A significant dependence on turbidity explained more than 70% of the variation in attenuation of ultraviolet irradiance at the shorter wavelengths. The direct ultraviolet irradiance can exceed 50% of the global ultraviolet irradiance in shallow waters (0–5 m), a significant result that is generally overlooked in optical and biological studies.