The "Red Dawn" dust storm on 22 and 23 September 2009, called "Red Dawn", was the largest to pass over Sydney in term of reduced visibility (400 m) since reliable records began in 1940. The maximum hourly PM 10 concentration measured near Sydney was 15,366 μg/m 3 at Bringelly and is the highest ever recorded for Sydney and possibly any Australian capital city. The Australian air quality standard of 50 μg/m 3 per 24 hours was massively exceeded at Randwick (1,734 μg/m 3) and Newcastle (2,426 μg/m 3). Red Dawn was caused by drought and the extreme wind conditions caused by a low pressure trough and cold front associated with a deep cutoff low pressure system. The source of the dust was the red sandplains of western New South Wales, the sandplains, riverine channels and lakes of the lower Lake Eyre Basin and Channel Country of Queensland. Between 22 September 2009 at 1400 to 23 September 2009, 0.3 Mt of PM 10 dust was transported off the coast between Albion Park and Newcastle (182 km length) near Sydney. The maximum hourly rate of PM 10 dust lost off the coast near Sydney was 71,015 t/h on 22 September at 2100. Calculating the total suspended particulate sediment lost off the Australian coast for the 3000 km long Red Dawn dust storm gives an estimate of 2.54 Mt for a plume height of 2500m. This is the first and largest offcontinent loss of soil ever reported using measured, as apposed to modelled, dust concentrations for Australia.

Soils are a fundamental component of terrestrial ecosystems, and play key roles in biogeochemical cycles and the ecology of microbial, plant and animal communities. Global increases in the intensity and frequency of ecological disturbances are driving major changes in the structure and function of forest ecosystems, yet little is known about the long-term impacts of disturbance on soils. Here we show that natural disturbance (fire) and human disturbances (clearcut logging and post-fire salvage logging) can significantly alter the composition of forest soils for far longer than previously recognized. Using extensive sampling across a multi-century chronosequence in some of the tallest and most carbon-dense forests worldwide (southern Australian, mountain ash (Eucalyptus regnans) forests), we provide compelling evidence that disturbance impacts on soils are evident up to least eight decades after disturbance, and potentially much longer. Relative to long-undisturbed forest (167 years old), sites subject to multiple fires, clearcut logging or salvage logging were characterized by soils with significantly lower values of a range of ecologically important measures at multiple depths, including available phosphorus and nitrate. Disturbance impacts on soils were most pronounced on sites subject to compounding perturbations, such as multiple fires and clearcut logging. Long-lasting impacts of disturbance on soil can have major ecological and functional implications.

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Q fever is a vaccine-preventable disease; despite this, high annual notification numbers are still recorded in Australia. We have previously shown seroprevalence in Queensland metropolitan regions is approaching that of rural areas. This study investigated the presence of nucleic acid from Coxiella burnetii, the agent responsible for Q fever, in a number of animal and environmental samples collected throughout Queensland, to identify potential sources of human infection. Samples were collected from 129 geographical locations and included urine, faeces and whole blood from 22 different animal species; 45 ticks were removed from two species, canines and possums; 151 soil samples; 72 atmospheric dust samples collected from two locations and 50 dust swabs collected from domestic vacuum cleaners. PCR testing was performed targeting the IS1111 and COM1 genes for the specific detection of C. burnetii DNA. There were 85 detections from 1318 animal samples, giving a detection rate for each sample type ranging from 2.1 to 6.8%. Equine samples produced a detection rate of 11.9%, whilst feline and canine samples showed detection rates of 7.8% and 5.2%, respectively. Native animals had varying detection rates: pooled urines from flying foxes had 7.8%, whilst koalas had 5.1%, and 6.7% of ticks screened were positive. The soil and dust samples showed the presence of C. burnetii DNA ranging from 2.0 to 6.9%, respectively. These data show that specimens from a variety of animal species and the general environment provide a number of potential sources for C. burnetii infections of humans living in Queensland. These previously unrecognized sources may account for the high seroprevalence rates seen in putative low-risk communities, including Q fever patients with no direct animal contact and those subjects living in a low-risk urban environment.