Sydney Water

PARAllel FACtor analysis (PARAFAC) is increasingly used to decompose fluorescence excitation emission matrices (EEMs) into their underlying chemical components. In the ideal case where fluorescence conforms to Beers Law, this process can lead to the mathematical identification and quantification of independently varying fluorophores. However, many practical and analytical hurdles stand between EEM datasets and their chemical interpretation. This article provides a tutorial in the practical application of PARAFAC to fluorescence datasets, demonstrated using a dissolved organic matter (DOM) fluorescence dataset. A new toolbox for MATLAB is presented to support improved visualisation and sensitivity analyses of PARAFAC models in fluorescence spectroscopy.

An online repository of published organic fluorescence spectra has been developed, which can be searched for quantitative matches with any set of unknown spectra.

The survival of culturable fecal coliforms, fecal streptococci, and Clostridium perfringens spores in freshwater and marine sediments from sites near sewage outfalls was studied. In laboratory studies, the inhibition of protozoan predators with cycloheximide allowed the fecal coliforms to grow in the sediment whereas the presence of predators resulted in a net die-off. C. perfringens spores did not appear either to be affected by predators or to die off throughout the duration of the experiments (28 days). Studies using in situ membrane diffusion chambers showed that, with the exception of C. perfringens, die-off of the test organisms to 10% of their initial numbers occurred in both marine and freshwater sediments within 85 days. The usual exponential decay model could not be applied to the sediment survival data, with the exception of the data for fecal streptococci. It was concluded that application of the usual decay model to the fecal coliform data was confounded by the complex relationship between growth and predation. The survival of seeded Escherichia coli in marine sediment was studied by using an enumeration method which detected viable but nonculturable bacteria. Throughout the duration of the experiment (68 days), the same proportion of E. coli organisms remained culturable, suggesting that sediment provides a favorable, nonstarvation environment for the bacteria.

A primary-structure analysis of the 16S rRNA gene was performed with 10 strains representing five described and one unidentified species of the genus Microcystis. The phylogenies determined illustrate the evolutionary affiliations among Microcystis strains, other cyanobacteria, and related plastids and bacteria. A cluster of 10 strains that included hepatotoxic isolates identified as Microcystis aeruginosa formed a monophyletic group. However, the genus Microcystis appeared to be polyphyletic and contained two strains that clustered with unicellular cyanobacteria belonging to the genus Synechococcus. The clustering of related Microcystis strains, including strains involved in the production of the cyclic peptide toxin microcystin, was consistent with cell morphology, gas vacuolation, and the low G + C contents of the genomes. The Microcystis lineage was also distinct from the lineage containing the unicellular genus Synechocystis and the filamentous, heterocyst-forming genus Nostoc. The secondary structure of a Microcystis 16S rRNA molecule was determined, and genus-specific sequence signatures were used to design primers that permitted identification of the potentially toxic cyanobacteria belonging to the genus Microcystis via DNA amplification.

Abstract The added value of biochar when applied along with fertilizers, beyond that of the fertilizers themselves, has not been summarized. Focusing on direct comparisons between biochar additions (≤20 t ha −1 ) – separately considering the addition or not of inorganic fertilizers ( IF ) and/or organic amendments ( OA ) along with biochar – and two different controls (with and without the addition of IF and/or OA ), we carried out a meta‐analysis to explain short‐term (1‐year) field responses in crop yield across different climates, soils, biochars and management practices worldwide. Compared with the non‐fertilized control, a 26% ( CI : 15%–40%) increase in yield was observed with the use of IF only, whereas that of biochar along with IF caused a 48% ( CI : 30%–70%) increase. Compared with the use of IF only, the addition of biochar along with IF caused a 15% ( CI : 11%–19%) increase in yield, indicating that biochar was as effective as fertilizers in increasing crop yields when added in combination. The use of biochar alone did not increase crop yield regardless of the control considered. Whereas in the short term, liming may have partly contributed to the beneficial effect of biochar (>90% was plant‐derived) when added along with IF , a separate meta‐analysis – using those studies that reported crop yields for different years after a single biochar application – showed a 31% ( CI : 17%–49%) increase in crop yield over time (≥ 3 years), which denotes the influence of biochar properties other than liming (i.e. an increase in CEC ). Our results also suggest that biochar application rates > 10 t ha −1 do not contribute to greater crop yield (at least in the short term). Data limitations precluded identification of the influence of feedstock, production conditions or climatic conditions without bias. As the response of crop yield to biochar addition was less a result of climatic zones or soil type than fertilizer use (chiefly N additions), the choice of nutrient addition along with biochar should be priorities for future research and development regardless of the region.

Abstract This paper describes a simple and inexpensive procedure for the rapid biological assessment of water quality in rivers and streams in eastern Australia. The procedure involves the standardized collection of samples of 100 macroinvertebrates from defined habitat types within a water body. Specimens are identified to family level only and a biotic index is calculated. Proposed future testing and evaluation are described, and the limitations of the rapid approach are discussed.

Life Cycle Assessment (LCA) is useful as an information tool for the examination of alternative future scenarios for strategic planning. Developing a life cycle assessment for a large water and wastewater system involves making methodological decisions about the level of detail which is retained through different stages of the process. In this article we discuss a methodology tailored to strategic planning needs which retains a high degree of model segmentation in order to enhance modeling of a large, complex system. This is illustrated by a case study of Sydney Water, which is Australia's largest water service provider. A prospective LCA was carried out to examine the potential environmental impacts of Sydney Water's total operations in the year 2021. To our knowledge this is the first study to create an LCA model of an integrated water and wastewater system with this degree of complexity. A "base case" system model was constructed to represent current operating assets as augmented and upgraded to 2021. The base case results provided a basis for the comparison of alternative future scenarios and for conclusions to be drawn regarding potential environmental improvements. The scenarios can be roughly classified in two categories: (1) options which improve the environmental performance across all impact categories and (2) options which improve one indicator and worsen others. Overall environmental improvements are achieved in all categories by the scenarios examining increased demand management, energy efficiency, energy generation, and additional energy recovery from biosolids. The scenarios which examined desalination of seawater and the upgrades of major coastal sewage treatment plants to secondary and tertiary treatment produced an improvement in one environmental indicator but deteriorations in all the other impact categories, indicating the environmental tradeoffs within the system. The desalination scenario produced a significant increase in greenhouse gas emissions due to coal-fired electricity generation for a small increase in water supply. Assessment of a greenfield scenario incorporating water demand management, on-site treatment, local irrigation, and centralized biosolids treatment indicates significant environmental improvements are possible relative to the assessment of a conventional system of corresponding scale.

Wastewater surveillance for pathogens using reverse transcription-polymerase chain reaction (RT-PCR) is an effective and resource-efficient tool for gathering community-level public health information, including the incidence of coronavirus disease-19 (COVID-19). Surveillance of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) in wastewater can potentially provide an early warning signal of COVID-19 infections in a community. The capacity of the world's environmental microbiology and virology laboratories for SARS-CoV-2 RNA characterization in wastewater is increasing rapidly. However, there are no standardized protocols or harmonized quality assurance and quality control (QA/QC) procedures for SARS-CoV-2 wastewater surveillance. This paper is a technical review of factors that can cause false-positive and false-negative errors in the surveillance of SARS-CoV-2 RNA in wastewater, culminating in recommended strategies that can be implemented to identify and mitigate some of these errors. Recommendations include stringent QA/QC measures, representative sampling approaches, effective virus concentration and efficient RNA extraction, PCR inhibition assessment, inclusion of sample processing controls, and considerations for RT-PCR assay selection and data interpretation. Clear data interpretation guidelines (e.g., determination of positive and negative samples) are critical, particularly when the incidence of SARS-CoV-2 in wastewater is low. Corrective and confirmatory actions must be in place for inconclusive results or results diverging from current trends (e.g., initial onset or reemergence of COVID-19 in a community). It is also prudent to perform interlaboratory comparisons to ensure results' reliability and interpretability for prospective and retrospective analyses. The strategies that are recommended in this review aim to improve SARS-CoV-2 characterization and detection for wastewater surveillance applications. A silver lining of the COVID-19 pandemic is that the efficacy of wastewater surveillance continues to be demonstrated during this global crisis. In the future, wastewater should also play an important role in the surveillance of a range of other communicable diseases.

Climate change and urbanization can increase pressures on groundwater resources, but little is known about how groundwater quality will change. Here, we use a global synthesis (n = 9,404) to reveal the drivers of dissolved organic carbon (DOC), which is an important component of water chemistry and substrate for microorganisms that control biogeochemical reactions. Dissolved inorganic chemistry, local climate and land use explained ~ 31% of observed variability in groundwater DOC, whilst aquifer age explained an additional 16%. We identify a 19% increase in DOC associated with urban land cover. We predict major groundwater DOC increases following changes in precipitation and temperature in key areas relying on groundwater. Climate change and conversion of natural or agricultural areas to urban areas will decrease groundwater quality and increase water treatment costs, compounding existing constraints on groundwater resources.

Groundwater comprises 95% of the liquid fresh water on Earth and contains a diverse mix of dissolved organic matter (DOM) molecules which play a significant role in the global carbon cycle. Currently, the storage times and degradation pathways of groundwater DOM are unclear, preventing an accurate estimate of groundwater carbon sources and sinks for global carbon budgets. Here we reveal the transformations of DOM in aging groundwater using ultra-high resolution mass spectrometry combined with radiocarbon dating. Long-term anoxia and a lack of photodegradation leads to the removal of oxidised DOM and a build-up of both reduced photodegradable formulae and aerobically biolabile formulae with a strong microbial signal. This contrasts with the degradation pathway of DOM in oxic marine, river, and lake systems. Our findings suggest that processes such as groundwater extraction and subterranean groundwater discharge to oceans could result in up to 13 Tg of highly photolabile and aerobically biolabile groundwater dissolved organic carbon released to surface environments per year, where it can be rapidly degraded. These findings highlight the importance of considering groundwater DOM in global carbon budgets.

The growth of planktonic cyanobacteria in a weir pool on the Lower Darling River, Australia, downstream of the major regulated Menindee Lake system was examined. Blooms of the saxitoxin producing freshwater cyanobacterium Anabaena circinalis occurred for two summers out of four studied. Large cell numbers of other cyanobacteria including Aphanizomenon, Planktolyngbya and Merismopedia also occurred during the same summer periods as the Anabaena blooms. The growth events also coincided with periods of improved light climate. Flow releases from the regulated Menindee Lakes System were assessed for their ability to either suppress bloom development or to mitigate pre-existing blooms over this period. A discharge of 300 ML/day (flow velocity of 0.03 m/s) was found to be sufficient to prevent prolonged periods of persistent thermal stratification, which also suppressed the development of A. circinalis blooms. A flow release of 3000 ML/day was effective at removing an established cyanobacterial bloom, and total cyanobacterial numbers declined from over 100 000 to <1000 cells/mL within a week. In two summers without blooms, higher flows and decreased light availability prevented the development of cyanobacterial blooms. Flow releases were effective at mitigating cyanobacterial growth through either the suppression of persistent thermal stratification or through dilution and translocation of cells. Greater discharges also increased turbidity, which diminished the growth of cyanobacteria through reduced light availability under the mixed conditions, which also reduced the ability for surface migration through buoyancy regulation. The volume of water required for different management strategies varied and is considered in terms of environmental allocations.

Abstract. Competition for water between humans and ecosystems is set to become a flash point in the coming decades in many parts of the world. An entirely new and comprehensive quantitative framework is needed to establish a holistic understanding of that competition, thereby enabling the development of effective mediation strategies. This paper presents a modeling study centered on the Murrumbidgee River basin (MRB). The MRB has witnessed a unique system dynamics over the last 100 years as a result of interactions between patterns of water management and climate driven hydrological variability. Data analysis has revealed a pendulum swing between agricultural development and restoration of environmental health and ecosystem services over different stages of basin-scale water resource development. A parsimonious, stylized, quasi-distributed coupled socio-hydrologic system model that simulates the two-way coupling between human and hydrological systems of the MRB is used to mimic and explain dominant features of the pendulum swing. The model consists of coupled nonlinear ordinary differential equations that describe the interaction between five state variables that govern the co-evolution: reservoir storage, irrigated area, human population, ecosystem health, and environmental awareness. The model simulations track the propagation of the external climatic and socio-economic drivers through this coupled, complex system to the emergence of the pendulum swing. The model results point to a competition between human "productive" and environmental "restorative" forces that underpin the pendulum swing. Both the forces are endogenous, i.e., generated by the system dynamics in response to external drivers and mediated by humans through technology change and environmental awareness, respectively. Sensitivity analysis carried out with the model further reveals that socio-hydrologic modeling can be used as a tool to explain or gain insight into observed co-evolutionary dynamics of diverse human–water coupled systems. This paper therefore contributes to the ultimate development of a generic modeling framework that can be applied to human–water coupled systems in different climatic and socio-economic settings.

The temporal and spatial variability of crescentic sandbars is analyzed with hourly long‐term (months) video observations collected at four barred sites and are qualitatively compared to the temporal and spatial variability predicted by hypotheses underpinning existing approaches and models for crescentic bar formation (edge‐wave template model, linear stability analysis, and nonlinear models). The observations, coming from the single barred beaches at Duck (North Carolina, USA) and Miyazaki (Kyushu, Japan), and from the double‐barred beaches at the northern Gold Coast (Queensland, Australia) and Noordwijk (Netherlands), show that crescentic sandbar wavelength and amplitude variations over space and time are very common. For instance, at any moment in time, the wavelength of the smallest and longest crescentic bar can differ by a factor of 2. Temporal changes in wavelength and amplitude result from merging and splitting of individual crescents, causing the “final” configuration of a crescentic sandbar system to be very different from the initial configuration. The Gold Coast data indicate that these intrinsically nonlinear interactions are an attempt of the crescentic bar system to self‐organize into a more uniform pattern, as splitting is usually confined to the longest crescentic bar observed, whereas merging usually combines the smallest crescentic bars into a longer bar. The observed spatial and temporal crescentic bar behavior contrasts qualitatively with behavior predicted from the edge‐wave template model and implies that the predictive skill of linear stability models is limited. Nonlinear models are potentially better suited for a comparison against these field observations; several suggestions to improve these models, and hence to facilitate a data‐model comparison, are made.

Satellite observations identify the Mongolian steppes as a hotspot of global biomass reduction, the extent of which is comparable with tropical rainforest deforestation. To conserve or restore these grasslands, the relative contributions of climate and human activities to degradation need to be understood. Here we use a recently developed 21-year (1988-2008) record of satellite based vegetation optical depth (VOD, a proxy for vegetation water content and aboveground biomass), to show that nearly all steppe grasslands in Mongolia experienced significant decreases in VOD. Approximately 60% of the VOD declines can be directly explained by variations in rainfall and surface temperature. After removing these climate induced influences, a significant decreasing trend still persists in the VOD residuals across regions of Mongolia. Correlations in spatial patterns and temporal trends suggest that a marked increase in goat density with associated grazing pressures and wild fires are the most likely non-climatic factors behind grassland degradation.

Summary It has been 75 yr since leaf respiratory metabolism in the light (day respiration) was identified as a low‐flux metabolic pathway that accompanies photosynthesis. In principle, it provides carbon backbones for nitrogen assimilation and evolves CO 2 and thus impacts on plant carbon and nitrogen balances. However, for a long time, uncertainties have remained as to whether techniques used to measure day respiratory efflux were valid and whether day respiration responded to environmental gaseous conditions. In the past few years, significant advances have been made using carbon isotopes, ‘omics’ analyses and surveys of respiration rates in mesocosms or ecosystems. There is substantial evidence that day respiration should be viewed as a highly dynamic metabolic pathway that interacts with photosynthesis and photorespiration and responds to atmospheric CO 2 mole fraction. The view of leaf day respiration as a constant and/or negligible parameter of net carbon exchange is now outdated and it should now be regarded as a central actor of plant carbon‐use efficiency. Contents Summary 986 I. Introduction 987 II. Pioneering metabolic studies of day respiration with 14 C 987 III. Metabolic flux pattern of day respiration 988 IV. Significance of day respiration for leaf N assimilation 991 V. Significance of day respiration for leaf gas exchange 992 VI. Is day respiration influenced by CO 2 mole fraction? 995 VII. Significance of day respiration at the plant and ecosystem levels 997 VIII. Conclusions and perspectives 998 References 998

Sea level rise (SLR) poses a hazard to ecosystems and economies in low-lying coastal and estuarine areas. To better understand the potential impacts of SLR in estuaries, a comprehensive review of existing theory, literature, and assessment tools is undertaken. In addition, several conceptual models are introduced to assist in understanding interlinked estuarine processes and their complex responses to SLR. This review indicates that SLR impacts in estuaries should not be assessed via static (bathtub) approaches as they fail to consider important hydrodynamic effects such as tidal wave amplification, dampening, and reflection. Where hydrodynamic models are used, the existing literature provides a relatively detailed understanding of how SLR will affect estuarine hydrodynamics (e.g., tides and inundation regimes). With regards to the current understanding of, and ability to model, the connections between altered hydrodynamics (under SLR) and dependent geomorphic, ecological, and bio-geochemical processes, significant knowledge gaps remain. This is of particular concern as there is currently a paradigm shift towards more integrated and holistic management of estuaries. Estuarine management under accelerating SLR is likely to become increasingly complex, as decision-making will be undertaken with uncertainty. As such, this review highlights that there is a fundamental requirement for more sophisticated and interdisciplinary studies that integrate physical, ecological, bio-geochemical, and geomorphic responses of estuaries to SLR.

Aim Vegetation optical depth (VOD) is an indicator of the water content of both woody and leaf components in terrestrial aboveground vegetation biomass that can be derived from passive microwave remote sensing. VOD is distinct from optical vegetation remote sensing data such as the normalized difference vegetation index in that it is: (a) less prone to saturation in dense canopies; (b) sensitive to both photosynthetic and non-photosynthetic biomass; and (c) less affected by atmospheric conditions. Our primary objective was to analyse a recently developed long-term VOD record and investigate how the vegetation water content of various land-cover types responded to environmental changes and human influences from 1988 to 2008. Location Global. Methods We first conducted Mann–Kendall trend tests on annual average VOD to identify regions with significant changes over the period 1988–2008. To diagnose the underlying cause of the observed changes, patterns for these identified regions were further compared with independent datasets of precipitation, crop production, deforestation and fire occurrence. Results (1) Over grassland and shrubland, VOD patterns corresponded strongly to temporal precipitation patterns. (2) Over croplands, annual average VOD showed a general increase that corresponded to reported crop production patterns and was attributed to a combination of precipitation patterns and agricultural improvements. (3) Over humid tropical forest, the spatial pattern of VOD decline agrees well with deforestation patterns; the 2005 Amazon drought corresponded with a temporary VOD decrease. (4) Over boreal forests, regional VOD declines are attributed to a combination of fires and clear cutting. Main conclusions Passive microwave remote sensing of VOD can be used to monitor global changes in total aboveground vegetation water content and biomass over various land-cover types. This new observational record can help in hydrological, agricultural, ecological and climate change studies, and provides new insights into large-scale vegetation change and its drivers.

Summary 1. Diatoms were sampled in the spring of 1994 and the autumn of 1995 at 137 pristine or near‐pristine reference sites on large and small streams at various altitudes in eastern New South Wales and Victoria. Scrapings were taken from five firm substrata across a range of microhabitat conditions at each site on each occasion. For each substratum, 100 valves were identified to genus level. 2. Multivariate statistical models were constructed to predict the probability of occurrence of each genus at a given site under near‐pristine conditions on the basis of physical features of the site that are not affected by human activity. Model predictions were compared with the flora observed at the reference sites and at 55 test sites affected by varying degrees of human disturbance. 3. Test sites were characterized more by the presence of genera not predicted by the model than by the absence of predicted genera. The degree of departure from model predictions was related mainly to increasing alkalinity, electrical conductivity, hardness and pH of river water. We therefore conclude that the main effect of human activity on the composition of diatom communities in the rivers of coastal south‐eastern Australia has been to increase genus richness through enrichment with alkaline salts. 4. The models did not perform as well as similar models applied to river macroinvertebrates at the family level, perhaps because of greater temporal variability in diatom communities and differences in the environmental variables to which diatoms and macroinvertebrates respond. Means of improving the current models are discussed.

Abstract. This paper presents a case study centred on the Murrumbidgee River basin in eastern Australia. It illustrates the dynamics of the balance between water extraction and use for food production, and efforts to mitigate and reverse consequent degradation of the riparian environment. In particular, the paper traces the history of a pendulum swing between an exclusive focus on agricultural development and food production in the initial stages and its attendant socio-economic benefits, followed by the gradual realization of the adverse environmental impacts, subsequent efforts to mitigate these with the use of remedial measures, and ultimately concerted efforts and externally imposed solutions to restore environmental health and ecosystem services. The 100-year history of development within the Murrumbidgee is divided into four eras, each underpinned by the dominance of different values and norms and turning points characterized by their changes. The various stages of development can be characterized by the dominance, in turn, of infrastructure systems, policy frameworks, economic instruments, and technological solutions. The paper argues that, to avoid these costly pendulum swings, management needs to be underpinned by long-term coupled socio-hydrologic system models that explicitly include the two-way coupling between human and hydrological systems, including the slow evolution of human values and norms relating to water and the environment. Such coupled human–water system models can provide insights into dominant controls of the trajectory of their co-evolution in a given system, and can also be used to interpret patterns of co-evolution of such coupled systems in different places across gradients of climatic, socio-economic and socio-cultural conditions, and in this way to help develop generalizable understanding.

A fecal analysis survey was undertaken to quantify animal inputs of pathogenic and indicator microorganisms in the temperate watersheds of Sydney, Australia. The feces from a range of domestic animals and wildlife were analyzed for the indicator bacteria fecal coliforms and Clostridium perfringens spores, the pathogenic protozoa Cryptosporidium and Giardia, and the enteric viruses adenovirus, enterovirus, and reovirus. Pathogen and fecal indicator concentrations were generally higher in domestic animal feces than in wildlife feces. Future studies to quantify potential pathogen risks in drinking-water watersheds should thus focus on quantifying pathogen loads from domestic animals and livestock rather than wildlife.