What determines soil organic carbon stocks in the grazing lands of north-eastern Australia?

This study aimed to unravel the effects of climate, topography, soil, and grazing management on soil organic carbon (SOC) stocks in the grazing lands of north-eastern Australia. We sampled for SOC stocks at 98 sites from 18 grazing properties across Queensland, Australia. These samples covered four nominal grazing management classes (Continuous, Rotational, Cell, and Exclosure), eight broad soil types, and a strong tropical to subtropical climatic gradient. Temperature and vapour-pressure deficit explained >80% of the variability of SOC stocks at cumulative equivalent mineral masses nominally representing 0-0.1 and 0-0.3m depths. Once detrended of climatic effects, SOC stocks were strongly influenced by total standing dry matter, soil type, and the dominant grass species. At 0-0.3m depth only, there was a weak negative association between stocking rate and climate-detrended SOC stocks, and Cell grazing was associated with smaller SOC stocks than Continuous grazing and Exclosure. In future, collection of quantitative information on stocking intensity, frequency, and duration may help to improve understanding of the effect of grazing management on SOC stocks. Further exploration of the links between grazing management and above- and below-ground biomass, perhaps inferred through remote sensing and/or simulation modelling, may assist large-area mapping of SOC stocks in northern Australia. © CSIRO 2013.

Assessing infant exposure to persistent organic pollutants via dietary intake in Australia

Persistent organic pollutants (POPs) including polybrominated diphenyl ethers (PBDEs); organochlorine pesticides (OCPs); and polychlorinated biphenyls (PCBs) persist in the environment, bioaccumulate, and pose a risk of causing adverse human health effects. Typically, exposure assessments undertaken by modeling existing intake data underestimate the concentrations of these chemicals in infants. This study aimed to determine concentrations of POPs in infant foods, assess exposure via dietary intake and compare this to historical exposure. Fruit purees, meat and vegetables, dairy desserts, cereals and jelly foods (n = 33) purchased in 2013 in Brisbane, Australia were analyzed. For OCPs and PCBs, concentrations ranged up to 95 pg/g fw and for PBDEs up to 32 pg/g fw with most analytes below the limit of detection. Daily intake is dependent on type and quantity of foods consumed. Consumption of a 140 g meal would result in intake ranging from 0 to 4.2 ng/day, 4.4 ng/day and 13.3 ng/day, for OCPs, PBDEs and PCBs, respectively. PBDEs were detected in 3/33 samples, OCPs in 9/33 samples and PCBs in 13/33 samples. Results from this study indicate exposure for infants via dietary (in contrast to dust and breast milk) intake in Australia contribute only a minor component to total exposure.

Integrating organic matter into banana plantation in North Queensland: the effects on soil properties

The major banana production areas in Australia are particularly sensitive to environments due to their close proximity to areas of World Heritage rainforest and the Great Barrier Reef catchment. Management of soil quality, nutrients and pesticides are vital to maintaining the integrity of these sensitive areas. Studies on cropping systems have suggested that integrating organic matter into ground cover management would improve the quality of soil under banana cultivation. In this study, an alternative management practice for bananas, which addresses the management of organic matter and fertiliser application, was assessed and compared to the conventional practice currently employed in the banana industry. Several chemical, physical and biological soil parameters were measured including: pH, electrical conductivity, water stable aggregates, bulk density, water filled pore space, porosity, water content, fluorescein diacetate hydrolyis (FDA) and beta-glucosidase activity. The alternative management practice did not have a significant impact of the production and growth of bananas but overall improved the quality of the soil. Although some differences were observed, the chemical and physical soil characteristics did not differ dramatically between the two management systems. The addition of organic matter resulted in the soil under alternative practice having higher FDA and beta-glucosidase levels, indicating higher microbial activity. The integration of organic matter into the management of bananas resulted in positive benefits on soil properties under bananas, however, methods of maintaining organic matter in the soil need to be further researched.

Structures of some unusual types of organic compounds

Structures of a variety of compounds isolated in reactions and elucidated with the help of spectral (uv,ir,nmr and mass) data, have been discussed. In a few cases, the assigned structures were confirmed by x-ray crystal structure analysis.

Photochemical Reactions in Oriented Systems

Modification of chemical reactions through the use of constrained and/or organized media has attracted a great deal of attention recently. Results from our laboratory in this direction which include a study of photochemical reactions in solid state and in cyclodextrins are presented here. A study of solid state photochemical behavior of coumarins has provided information regarding subtler aspects of topochemical postulates of photodimerization. Results pertaining to geometrical criteria for photodimerization and "chloro" as a crystal engineering group are discussed. As a part of an attempt to correlate chemical reactivity with molecular packing in the solid state, photooxidation of diarylthioketones in the solid state has been investigated. The observed differences in the reactivity of these crystals are rationalized in terms of crystal packing. Though cyclodextrins have been extensively studied, very few photochemical reactions involving molecules complexed to cyclodextrins have been examined. In this connection, the utility of cyclodextrins in bringing about selectivity in photochemical reactions through the study of excited state behavior of olefins and aryl alkyl ketones has been demonstrated in our laboratory.

Micellar control of photochemical reactions

Micelles as media for chemical reactions exhibit features that are unique in comparison to ordinary non-aqueous or aqueous solvent media. A thermal or photochemical reaction conducted in micellar media is influenced by the micellar environmental effects resulting in control and/or modification of reactivity. The salient features of micelles and their influence on photochemical reactivity are briefly discussed in this paper.

Persistent organic pollutants in matched breast milk and infant faeces samples

Assessing blood concentration of persistent organic pollutants (POPs) in infants is difficult due to the ethical and practical difficulties in obtaining sufficient quantities of blood. To determine whether measuring POPs in faeces might reflect blood concentration during infancy, we measured the concentrations of a range of POPs (i.e. polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and organochlorine pesticides (OCPs)) in a pilot study using matched breast milk and infant faecal samples obtained from ten mother-child pairs. All infants were breast fed, with 8 of them also receiving solid food at the time of faecal sampling. In this small dataset faecal concentrations (range 0.01-41ngg-1 lipid) are strongly associated with milk concentrations (range 0.02-230ngg-1 lipid). Associations with other factors generally could not be detected in this dataset, with the exception of a small effect of age or growth. Different sources (external or internal) of exposure appeared to directly influence faecal concentrations of different chemicals based on different inter-individual variability in the faeces-to-milk concentration ratio Rfm. Overall, the matrix of faeces as an external measure of internal exposure in infants looks promising for some chemicals and is worth assessing further in larger datasets.

Defining the density debate in Brisbane: how urban consolidation is represented in the media

Rapid population growth, changing demographic profiles and increased focus on sustainable urban form has led to significant changes in settlement patterns in Australian cities. Growth management strategies are increasingly employed to help cities manage strain on infrastructure, housing and ecosystems. Urban consolidation is one such strategy and has been adopted by all Australian capital cities. Despite strong governmental support, urban consolidation has triggered much academic debate and has often been accompanied by staunch community opposition and complaints from the development industry about barriers to the provision of higher density housing. Greater understanding of stakeholder representations of higher density housing is important for planning, given the strong policy focus on urban consolidation nationally. This paper contributes to existing urban consolidation literature by empirically demonstrating how urban consolidation is represented in Brisbane’s newspaper media through the use of metaphors. Its conceptual departure point is Social Representations Theory, drawing on the theory’s notion of objectification to illustrate how the media translates the abstract notion of urban consolidation into a tangible and understandable object. The objectification of urban consolidation is identified and discussed relative to four themes: land use conflict; growth; neighbourhood change and apartment living. This paper argues that understanding stakeholder representations is important for planners seeking to promote and negotiate delivery of higher density development. It concludes that stakeholder representations can highlight key areas of contention to be addressed by planners, provide indications on the likelihood of public acceptance of increased housing densities and delineate the boundaries of urban consolidation debates.

Shaping urban consolidation debates: Social representations in Brisbane newspaper media

Recent international trends towards urban consolidation, intended to reduce outward urban sprawl by concentrating growth within existing neighbourhoods, can cause contention in cities. Understanding how the mass media represents urban consolidation can lead to more informed and democratic planning practices. This paper employs Social Representations Theory to identify and understand representations of urban consolidation in newspaper media. The theory recognises that the media is a key purveyor of public discourse and can reflect, shape or suppress ideas circulating in society. This novel approach has not previously been applied to understanding social representations of urban consolidation strategies in the mass media. The rapidly growing and changing city of Brisbane, Australia, is utilised as a case study. Brisbane is situated in South East Queensland, the fastest growing region in Australia, and is governed by regional and local planning policies that strongly support increased densities in existing urban areas. Findings from a quantitative textual analysis of 449 articles published in Brisbane newspapers between 2007 and 2014 reveal key clusters and classes of co-occurring words that represent dominant social representations apparent in the newspaper corpus. The paper provides two key conclusions. The first is that social representations occurring in mass media represent an important source of information about ‘common sense’ understandings and evaluations of urban consolidation debates. The second is that urban consolidation is represented as a ultifaceted issue, including interrelated themes of housing,sustainable population growth, investment strategies and the interplay between politics and planning

Organic contaminants - occurrence and biological effects in the Baltic Sea

The Baltic Sea was studied with respect to selected organic contaminants and their ecotoxicology. The research consisted of analyses of total hydrocarbons, polycyclic aromatic hydrocarbons, bile metabolites, hepatic ethoxyresorufin-O-deethylase (EROD) activity, polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs). The contaminants were measured from various matrices, such as seawater, sediment and biota. The methods of analysis were evaluated and refined to comparability of the results. Polyaromatic hydrocarbons, originating from petroleum, are known to be among the most harmful substances to the marine environment. In Baltic subsurface water, seasonal dependence of the total hydrocarbon concentrations (THCs) was seen. Although concentrations of parent polycyclic aromatic hydrocarbons (PAHs) in sediment surface varied between 64 and 5161 ug kg-1 (dw), concentrations above 860 ug kg-1 (dw) were found in all the studied sub-basins of the Baltic Sea. Concentrations commonly considered to substantially increase the risk of liver disease and reproductive impairment in fish, as well as potential effects on growth (above 1000 ug kg-1 dw), were found in all the studied sub-basins of the Baltic Sea except Kattegat. Thus, considerable pollution in sediments was indicated. In bivalves, the sums of 12 PAHs varied on a wet weight basis between 44 and 298 ug kg-1 (ww). The predominant PAHs were high molecular weight and the PAH profiles of M. balthica differed from those found in sediment from the same area. The PAHs were both pyrolytic and petrogenic in origin, and a contribution from diesel engines was found, which indicates pollution of the Baltic Sea, most likely caused by the steadily increasing shipping in the area. The HPLC methods developed for hepatic EROD activity and bile metabolite measurements proved to be fast and suitable for the study of biological effects. A mixed function oxygenase enzyme system in Baltic Sea perch collected from the Gulf of Finland was induced slightly: EROD activity in perch varied from 0.30 14 pmol min-1 mg-1 protein. This range can be considered to be comparable to background values. Recent PAH exposure was also indicated by enhanced levels (213 and 1149 ug kg-1) of the bile metabolite 1-hydroxypyrene. No correlation was indicated between hepatic EROD activity and concentration of 1-hydroxypyrene in bile. PCBs and OCPs were observed in Baltic Sea sediment, bivalves and herring. Sums of seven CBs in surface sediment (0 5 cm) ranged from 0.04 to 6.2 ug kg-1 (dw) and sums of three DDTs from 0.13 to 5.0 ug kg-1 (dw). The highest levels of contaminants were found in the most eastern area of the Gulf of Finland where the highest total carbon and nitrogen content was found and where the lowest percentage proportion of p,p -DDT was found. The highest concentrations of CBs and the lowest concentration of DDTs were found in M. balthica from the Gulf of Finland. The highest levels of DDTs were found in M. balthica from the Hanö Bight, which is the outer part of the Bornholm Basin close to the Swedish mainland. In bivalves, the sums of seven CBs were 72 108 ug kg-1 (lw) and the sums of three DDTs were 66 139 ug kg-1 (lw). Results from temporal trend monitoring showed, that during the period 1985 2002, the concentrations of seven CBs in two-year-old female Baltic herring were clearly decreased, from 9 16 to 2 6 ug kg-1 (ww) in the northern Baltic Sea. At the same time, concentrations of three DDTs declined from 8 15 to 1 5 ug kg-1 (ww). The total concentration of the fat-soluble CBs and DDTs in Baltic herring muscle was shown to be age-dependent; the average concentrations in ten-year-old Baltic herring were three to five-fold higher than in two-year-old herring. In Baltic herring and bivalves, as well as in surface sediments, CB 138 and CB153 were predominant among CBs, whereas among DDTs p,p'-DDD predominated in sediment and p,p'-DDE in bivalves and Baltic herring muscle. Baltic Sea sediments are potential sources of contaminants that may become available for bioaccumulation. Based on ecotoxicological assessment criteria, cause for concern regarding CBs in sediments was indicated for the Gulf of Finland and the northern Baltic Proper, and for the northern Baltic Sea regarding CBs in Baltic herring more than two years old. Statistical classification of selected organic contaminants indicated high-level contamination for p,p'-DDT, p,p'-DDD, p,p'-DDE, total DDTs, HCB, CB118 and CB153 in muscle of Baltic herring in age groups two to ten years; in contrast, concentrations of a-HCH and g-HCH were found to be moderate. The concentrations of DDTs and CBs in bivalves is sufficient to cause biological effects, and demonstrates that long-term biological effects are still possible in the case of DDTs in the Hanö Bight.

The effect of pasture utilization rate on stocks of soil organic carbon and total nitrogen in a semi-arid tropical grassland

The influence of grazing management on total soil organic carbon (SOC) and soil total nitrogen (TN) in tropical grasslands is an issue of considerable ecological and economic interest. Here we have used linear mixed models to investigate the effect of grazing management on stocks of SOC and TN in the top 0.5 m of the soil profile. The study site was a long-term pasture utilization experiment, 26 years after the experiment was established for sheep grazing on native Mitchell grass (Astrebla spp.) pasture in northern Australia. The pasture utilization rates were between 0% (exclosure) and 80%, assessed visually. We found that a significant amount of TN had been lost from the top 0.1 m of the soil profile as a result of grazing, with 80% pasture utilization resulting in a loss of 84 kg ha−1 over the 26-year period. There was no significant effect of pasture utilization rate on TN when greater soil depths were considered. There was no significant effect of pasture utilization rate on stocks of SOC and soil particulate organic carbon (POC), or the C:N ratio at any depth; however, visual trends in the data suggested some agreement with the literature, whereby increased grazing pressure appeared to: (i) decrease SOC and POC stocks; and, (ii) increase the C:N ratio. Overall, the statistical power of the study was limited, and future research would benefit from a more comprehensive sampling scheme. Previous studies at the site have found that a pasture utilization rate of 30% is sustainable for grazing production on Mitchell grass; however, given our results, we conclude that N inputs (possibly through management of native N2-fixing pasture legumes) should be made for long-term maintenance of soil health, and pasture productivity, within this ecosystem.

Odour, dust and non-methane volatile organic-compound emissions from tunnel-ventilated layer-chicken sheds: a case study of two farms

An observational study was undertaken to measure odour and dust (PM10 and PM2.5) emission rates and identify non-methane volatile organic compounds (NMVOCs) and odorants in the exhaust air from two tunnel-ventilated layer-chicken sheds that were configured with multi-tiered cages and manure belts. The study sites were located in south-eastern Queensland and the West Gippsland region of Victoria, Australia. Samples were collected in summer and winter on sequential days across the manure-belt cleaning cycle. Odour emissions ranged from 58 to 512 ou/s per 1000 birds (0.03-0.27 ou/s.kg) and dust emission rates ranged 0.014-0.184 mg/s per 1000 birds for PM10 and 0.001-0.190 mg/s per 1000 birds for PM2.5. Twenty NMVOCs were identified, including three that were also identified as odorants using thermal desorption-gas chromatography-mass spectrometry/olfactometry analysis. Odour emission rates were observed to vary with the amount of manure accumulation on the manure belts, being lowest 2-4 days after removing manure. Odour emission rates were also observed to vary with diurnal and seasonal changes in ventilation rate. Dust emissions were observed to increase with ventilation rate but not with manure accumulation. Some NMVOCs were identified at both farms and in different seasons whereas others were observed only at one farm or in one season, indicating that odorant composition was influenced by farm-specific practices and season.