Science communication is integral to attracting widespread participation in bushfire recovery citizen science

The 2019/20 bushfire season was a catastrophic event affecting large areas of Australia. Due to the devastating impact on biodiversity, the Australian public wanted to contribute towards assessing the impact of this disaster. To address this, three citizen science projects were established to engage citizen scientists in various aspects of environmental recovery. The projects offered different ways of participating, ranging from online, through to community field events, including those requiring specialised localised knowledge. As a result, communication approaches targeting different audiences were required. Here, we detail the communication strategies employed to promote and engage a diverse national and global audience in bushfire recovery projects. We provide metrics and analysis on how and where we promoted projects, including a breakdown of participation numbers for each project. We detail lessons learnt, and how we would improve our communication approach for future disaster recovery events to increase awareness at a community level and more broadly. Despite numerous challenges, including organising public-facing events during a global pandemic, the program serves as an exemplar of how to successfully partner with communities, research teams and government to enable citizen scientists to make meaningful, valuable and timely contributions to research. Ultimately, the program enabled widespread community involvement in bushfire recovery and filled gaps in baseline and post-fire data

Field-based measurements of sulfur gas emissions from an agricultural coastal acid sulfate soil, eastern Australia

The emissions of biogenic hydrogen sulfide (H₂S) and sulfur dioxide (SO₂) play important roles in the global atmospheric sulfur (S) cycle. Field-based investigations using ultraviolet fluorescence spectroscopy show that drained acid sulfate soils (ASS) are a potentially unaccounted source of biogenic H₂S and SO₂. Significant diurnal variations were evident in SO₂ fluxes, with average daytime measurements 9.3-16.5-fold greater than night-time emissions. Similar diurnal patterns in H₂S fluxes were observed but proved statistically insignificant. The results from simultaneously collected micrometeorological measurements suggest that emissions of SO₂ and H₂S are most likely occurring via different processes. The SO₂ fluxes are closely linked to surface soil temperature and moisture content, whereas H₂S is constantly emitted from the land surface at the two study sites. Drained ASS are most likely mapped as agricultural lands rather than drained backswamps. Therefore, these areas are likely to be assigned H₂S and SO₂ flux values of zero in greenhouse gas species inventories. These findings suggest a need to expand these measurements to other drained ASS areas to refine regional (and possibly global) atmospheric S budgets. Further research is necessary to elucidate the sources of measured S compounds, and specifically whether they are limited to individual agricultural drainage patterns in ASS

Critical coagulation in sulfidic sediments from an east-coast Australian acid sulfate landscape

Sulfidic clays are agriculturally and environmentally important. In this work we examine the impacts of electrolytes and pH on the behaviour of colloidal clay mineral particles extracted from such sediments. The distribution of ferrous iron released by pyrite oxidation, aluminium by acidic weathering and cations in soils and pore waters in the field are reported. The behaviour of open-structured sulfidic colloidal clay mineral particles in response to changes in solution ionic composition were studied; (i) to evaluate the effects of natural oxidation of iron sulfide material in pedogenic development, and (ii) to investigate the response of these sediments to changes in pore water ionic composition as an option for soft sediment engineered dewatering. Photon correlation spectroscopy (PCS) was used to quantify these effects. As expected, Mg2+ and Ca2+ were more effective in inducing coagulation of the colloidal clay mineral particles than Na+; however, the effect was more pronounced than theoretically expected according to DLVO theory. Comparing the presence/absence of protons in cation saturated experiments showed new evidence for the formation of Hcolloidal clay mineral particle complexes that resist competitive cation exchange. The critical concentrations of acidic cations required for mass rapid aggregation in these experiments is comparable to the pore water composition within the soil profile where structural collapse has already occurred

Holocene evolution of the wave-dominated embayed Moruya coastline, southeastern Australia: Sediment sources, transport rates and alongshore interconnectivity

© 2020 Sediment budgets on wave-dominated coastlines are important in determining shoreline behaviour and are primarily inherited from geological-scale coastal evolutionary history. Sediment compartments provide a framework to conceptualise and investigate sediment budgets over a range of time and space scales. This study aims to assess the sediment budget for a secondary coastal compartment on the New South Wales (NSW) south coast ∼26 km in length and containing five adjacent but discrete Holocene coastal bay barriers: Barlings Beach, Broulee Beach, Bengello Beach, Moruya Heads Beach and Pedro Beach. Building on earlier morphostratigraphic studies, a new series of Optically Stimulated Luminescence (OSL) ages are presented for foredune ridge sequences at previously un-dated sites. Additional Ground Penetrating Radar (GPR) transects complement earlier stratigraphic datasets, and seamless topographic and bathymetric LiDAR datasets provide insight into subaerial coastal deposits and inner shelf morphology in this region. The results demonstrate that barriers within the compartment have two different sediment sources. The barriers are dominated by shoreface supply of quartz-rich sand transported onshore as shoreface morphology evolved towards equilibrium. Skeletal carbonate sand became an important component of the sediment budget for the northern Barlings and Broulee beaches after ∼3000 years ago. Shoreline progradation at Bengello Beach has been steady throughout the mid-to late- Holocene. Bengello contains the largest volume of Holocene sand and accreted at an average rate of 3.1 m3/m/yr (for the current shoreline length). The other barrier systems have experienced changes in sediment accumulation rate as their shorelines prograded seaward resulting in changes to their alongshore interconnectivity. Rapid filling of the Pedro Beach embayment by ∼4000 years ago initiated headland bypassing and northward sand transport to Moruya Heads Beach which only then commenced progradation. In contrast, as Broulee and Bengello Beaches prograded they converged in the lee of Broulee Island forming a tombolo which led to division of the former continuous shoreline into two. A marked increase in skeletal carbonate content at Broulee occurred after this separation attesting to the restriction of the southern quartz-sand source replaced by local carbonate production. This study emphasises the importance of understanding the long-term temporal variability in sediment budget and embayment interconnectivity in determining shoreline response to changing boundary conditions such as sea level and wave climate as well as contemporary anthropogenic influences

Uranium Binding Mechanisms of the Acid-Tolerant Fungus <i>Coniochaeta fodinicola</i>

The uptake and binding of uranium [as (UO₂)²⁺] by a moderately acidophilic fungus, <i>Coniochaeta fodinicola</i>, recently isolated from a uranium mine site, is examined in this work in order to better understand the potential impact of organisms such as this on uranium sequestration in hydrometallurgical systems. Our results show that the viability of the fungal biomass is critical to their capacity to remove uranium from solution. Indeed, live biomass (viable cells based on vital staining) were capable of removing ∼16 mg U/g dry weight in contrast with dead biomass (autoclaved) which removed ∼45 mg U/g dry weight after 2 h. Furthermore, the uranium binds with different strength, with a fraction ranging from ∼20–50% being easily leached from the exposed biomass by a 10 min acid wash. Results from X-ray absorption spectroscopy measurements show that the strength of uranium binding is strongly influenced by cell viability, with live cells showing a more well-ordered uranium bonding environment, while the distance to carbon or phosphorus second neighbors is similar in all samples. When coupled with time-resolved laser fluorescence and Fourier transformed infrared measurements, the importance of organic acids, phosphates, and polysaccharides, likely released with fungal cell death, appear to be the primary determinants of uranium binding in this system. These results provide an important progression to our understanding with regard to uranium sequestration in hydrometallurgical applications with implications to the unwanted retention of uranium in biofilms and/or its mobility in a remediation context

Removal of Trace Uranium from Groundwaters Using Membrane Capacitive Deionization Desalination for Potable Supply in Remote Communities: Bench, Pilot, and Field Scale Investigations

The performance of membrane capacitive deionization (MCDI) desalination was investigated at bench, pilot, and field scales for the removal of uranium from groundwater. It was found that up to 98.9% of the uranium can be removed using MCDI from a groundwater source containing 50 μg/L uranium, with the majority (94.5%) being retained on the anode. Uranium was found to physiochemically adsorb to the electrode without the application of a potential by displacing chloride ions, with 16.6% uranium removal at the bench scale via this non-electrochemical process. This displacement of chloride did not occur during the MCDI adsorption phase with the adsorption of all ions remaining constant during a time series analysis on the pilot unit. For the scenarios tested on the pilot unit, the flowrate of the product water ranged from 0.15 to 0.23 m3/h, electrode energy consumption from 0.28 to 0.51 kW h/m3, and water recovery from 69 to 86%. A portion (13–53% on the pilot unit) of the uranium was found to remain on the electrodes after the brine discharge phase with conventional cleaning techniques unable to release this retained uranium. MCDI was found to be a suitable means to remove uranium from groundwater systems though with the need to manage the accumulation of uranium on the electrodes over time

Influence of Dissolved Silicate on Rates of Fe(II) Oxidation

Increasing concentrations of dissolved silicate progressively retard Fe­(II) oxidation kinetics in the circum-neutral pH range 6.0–7.0. As Si:Fe molar ratios increase from 0 to 2, the primary Fe­(III) oxidation product transitions from lepidocrocite to a ferrihydrite/silica-ferrihydrite composite. Empirical results, supported by chemical kinetic modeling, indicated that the decreased heterogeneous oxidation rate was not due to differences in absolute Fe­(II) sorption between the two solids types or competition for adsorption sites in the presence of silicate. Rather, competitive desorption experiments suggest Fe­(II) was associated with more weakly bound, outer-sphere complexes on silica-ferrihydrite compared to lepidocrocite. A reduction in extent of inner-sphere Fe­(II) complexation on silica-ferrihydrite confers a decreased ability for Fe­(II) to undergo surface-induced hydrolysis via electronic configuration alterations, thereby inhibiting the heterogeneous Fe­(II) oxidation mechanism. Water samples from a legacy radioactive waste site (Little Forest, Australia) were shown to exhibit a similar pattern of Fe­(II) oxidation retardation derived from elevated silicate concentrations. These findings have important implications for contaminant migration at this site as well as a variety of other groundwater/high silicate containing natural and engineered sites that might undergo iron redox fluctuations