Legacy effects of historical gold mining on floodplains of an Australian river.

The gold rush at the end of the nineteenth century in south-eastern Australia resulted in the mobilization and re-deposition of vast quantities of tailings that modified the geomorphology of the associated river valleys. Previous studies of contamination risk in these systems have either been performed directly on mine wastes (e.g.

Military Use of Point of Care Ultrasound (POCUS).

Background: Point of care ultrasound (POCUS) offers multiple capabilities in a relatively small, lightweight device to military clinicians of all types and levels in multiple environments. Its application in diagnostics, procedural guidance, and patient monitoring has not been fully explored by the Military Health System (MHS). The purpose of this narrative review of the literature was to examine the overall use of POCUS in military settings, as well as the level of ultrasound training provided.

Airway Management in the Prehospital, Combat Environment: Analysis of After-Action Reviews and Lessons Learned.

Introduction: Airway compromise is the second leading cause of potentially survivable death on the battlefield. Studies show that airway management is a challenge in prehospital combat care with high error and missed opportunity rates. Lacking is user information on the perceived reasons for the challenges.

Modelling food-web mediated effects of hydrological variability and environmental flows.

Environmental flows are designed to enhance aquatic ecosystems through a variety of mechanisms; however, to date most attention has been paid to the effects on habitat quality and life-history triggers, especially for fish and vegetation. The effects of environmental flows on food webs have so far received little attention, despite food-web thinking being fundamental to understanding of river ecosystems. Understanding environmental flows in a food-web context can help scientists and policy-makers better understand and manage outcomes of flow alteration and restoration.

Adaptive Management of Return Flows: Lessons from a Case Study in Environmental Water Delivery to a Floodplain River.

For many floodplain rivers, reinstating wetland connectivity is necessary for ecosystems to recover from decades of regulation. Environmental return flows (the managed delivery of wetland water to an adjacent river) can be used strategically to facilitate natural ecosystem connectivity, enabling the transfer of nutrients, energy, and biota from wetland habitats to the river. Using an informal adaptive management framework, we delivered return flows from a forested wetland complex into a large lowland river in south-eastern Australia.

The severity of sediment desiccation affects the adsorption characteristics and speciation of phosphorus.

Phosphorus is an important nutrient for plants and algae, and can be the limiting nutrient in aquatic ecosystems. However, oversupply can lead to significant water quality issues. The largest source and sink of P in most aquatic systems is the sediment.

Exploring the relationship between the optical properties of water and the quality and quantity of dissolved organic carbon in aquatic ecosystems: strong correlations do not always mean strong predictive power.

Optical absorbance and fluorescence spectroscopies have the potential to play an important role in monitoring aquatic ecosystems. This paper explores the relationship between the optical absorption and fluorescence characteristics of water samples taken from 18 sites (spanning a range of aquatic environments including lowland rivers, small and large dams, and floodplain wetlands) with their dissolved organic carbon (DOC) concentration and 28 days bioavailability Both optical absorbance in the ultraviolet region and fluorescence above excitation wavelengths of about 240 nm and emission wavelengths above about 350 were correlated with DOC concentration (r(2) > 0.8).

Characterisation of adaptive genetic diversity in environmentally contrasted populations of Eucalyptus camaldulensis Dehnh. (river red gum).

As an increasing number of ecosystems face departures from long standing environmental conditions under climate change, our understanding of the capacity of species to adapt will become important for directing conservation and management of biodiversity. Insights into the potential for genetic adaptation might be gained by assessing genomic signatures of adaptation to historic or prevailing environmental conditions. The river red gum (Eucalyptus camaldulensis Dehnh.

Options for managing hypoxic blackwater in river systems: case studies and framework.

Hypoxic blackwater events occur when large amounts of organic material are leached into a water body (e.g., during floodplain inundation) and rapid metabolism of this carbon depletes oxygen from the water column, often with catastrophic effects on the aquatic environment.

Proton and iron binding by the cyanobacterial toxin microcystin-LR.

Microcystins (MCs) are a group of hepatotoxins produced by cyanobacteria that have not had their functional role or the environmental factors that trigger production clearly determined. One suggestion is that microcystins are siderophores (i.e.

Impacts of inundation and drought on eukaryote biodiversity in semi-arid floodplain soils.

Floodplain ecosystems are characterized by alternating wet and dry phases and periodic inundation defines their ecological character. Climate change, river regulation and the construction of levees have substantially altered natural flooding and drying regimes worldwide with uncertain effects on key biotic groups. In southern Australia, we hypothesized that soil eukaryotic communities in climate change affected areas of a semi-arid floodplain would transition towards comprising mainly dry-soil specialist species with increasing drought severity.

Options for managing hypoxic blackwater events in river systems: a review.

Blackwater events are characterised by a high concentration of dissolved organic carbon in the water column. They occur naturally in lowland rivers with forested floodplains and bring a variety of benefits to both aquatic and floodplain biota. However, particularly when accompanied by high temperatures, respiration of the organic carbon may cause blackwater to become hypoxic.

Provisioning of bioavailable carbon between the wet and dry phases in a semi-arid floodplain.

Ecosystem functioning on arid and semi-arid floodplains may be described by two alternate traditional paradigms. The pulse-reserve model suggests that rainfall is the main driver of plant growth and subsequent carbon and energy reserve formation in the soil of arid and semi-arid regions. The flood pulse concept suggests that periodic flooding facilitates the two-way transfer of materials between a river and its adjacent floodplain, but focuses mainly on the period when the floodplain is inundated.

Rehabilitation options for inland waterways impacted by sulfidic sediments--field trials in a south-eastern Australian wetland.

The accumulation of significant pools of sulfidic sediments in inland wetlands and creeks is an emerging risk for the management of inland waterways. We used replicated plot trials to appraise the viability of various strategies for neutralizing oxidized, acidified sulfidic sediments in a highly degraded wetland. Of the twenty different treatments trialed only addition of calcium hydroxide or calcium carbonate, burning of wood, and planting of Phragmites australis, Typha domingensis and Atriplex nummularia into beds prepared with CaCO3 or P.

Impact of sulfate pollution on anaerobic biogeochemical cycles in a wetland sediment.

The impact of sulfate pollution is increasingly being seen as an issue in the management of inland aquatic ecosystems. In this study we use sediment slurry experiments to explore the addition of sulfate, with or without added carbon, on the anaerobic biogeochemical cycles in a wetland sediment that previously had not been exposed to high levels of sulfate. Specifically we looked at the cycling of S (sulfate, dissolved and particulate sulfide--the latter measured as acid volatile sulfide; AVS), C (carbon dioxide, bicarbonate, methane and the short chain volatile fatty acids formate, acetate, butyrate and propionate), N (dinitrogen, ammonium, nitrate and nitrite) and redox active metals (Fe(II) and Mn(II)).

Acidification and buffering mechanisms in acid sulfate soil wetlands of the Murray-Darling Basin, Australia.

The acid generation mechanisms and neutralizing capacities of sulfidic sediments from two inland wetlands have been studied in order to understand the response of these types of systems to drying events. The two systems show vastly different responses to oxidation, with one (Bottle Bend (BB) lagoon) having virtually no acid neutralizing capacity (ANC) and the other (Psyche Bend (PB) lagoon) an ANC that is an order of magnitude greater than the acid generation potential. While BB strongly acidifies during oxidation the free acid generation is less than that expected from the measured proton production and consumption processes, with additional proton consumption attributed to the formation of an acid-anion (chloride) FeIII (oxyhydr)oxide product, similar to akaganéite (Fe(OH)2.

Rehabilitation options for inland waterways impacted by sulfidic sediments--a synthesis.

The build up of reduced inorganic sulfur in the sediments of inland wetlands and creeks is an emerging risk for the management of inland waterways and is a direct result of secondary salinisation. Inappropriate management of these sediments can lead to a number of adverse environmental outcomes, the most dramatic of which is the extreme acidification of inland waterways, but can also include deoxygenation and the release of heavy metals. This paper explores possible management options for reducing the impact of sulfidic sediments on inland waterways based on previous research into ameliorating the impact of acid mine and acid rock drainage and coastal acid sulfate soils.

Drivers of water quality in a large water storage reservoir during a period of extreme drawdown.

This study examined the drivers of water quality in a large water storage reservoir (Lake Hume) during a period of extreme drawdown (to less than 3% of capacity). During the period of extreme drawdown, the reservoir can be thought of as consisting of three separate but inter-related parcels of water. The warm surface mixed layer was about 6m deep.