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The complex study of complexes: the first well-supported phylogeny of two species complexes within genus Caridina (Decapoda: Caridea: Atyidae) sheds light on evolution, biogeography, and habitat
No full textAtyid shrimps, a key component of tropical freshwater ecosystems, face multiple anthropogenic threats and thus need special attention. With more than 300 described species, the genus Caridina is the most speciose of all the Caridea infra-order. Caridina spp.occupy diverse habitats in tropical freshwaters of the Indo-West Pacific region. Several species complexes have been recognized, based on common morphological features, but little is known about how well these morphological characteristics align with phylogenetic characteristics. Furthermore, no phylogeny of the genus Caridina published so far has provided well-resolved and supported relationships among different species, thus impeding the possibility of proposing evolutionary hypotheses. In this study we used next generation sequencing (NGS) to provide new insights into the phylogenetic relationships among the genus Caridina, focusing on two complexes: ‘Caridina nilotica’ and ‘Caridina weberi’. We collected 92 specimens belonging to these two groups from most of their known geographical range, representing 50 species, for which we sequenced seven mitochondrial genes and two nuclear markers using ion torrent NGS. We performed a phylogenetic analysis, which yielded the first well-supported tree for the genus Caridina. On this tree were mapped the geographic ranges and the habitats used by the different species, and a time calibration was tested. We found the driving factors that most likely account for separation of clades are differences in habitat and to a lesser extent geography. This work provides new insights into the taxonomy of this group and identifies opportunities for further studies in order to fill knowledge gaps that currently impede the management and conservation of atyid species
Quantifying the transfer of prey δ15N signatures into coral holobiont nitrogen pools
No full textNitrogen stable isotope (δ15N) signatures of coral and skeletal tissues are commonly used to identify spatial and temporal patterns in the source and supply of nitrogen to coral reefs. A 15N labelled particulate food source (rotifers) was used to quantify the incorporation of prey nitrogen into the nitrogen pools (coral, algal tissues and skeletal organic matter) of Porites lutea, and to estimate the time taken for the δ15N signature of source nitrogen to be reflected in the different tissue fractions of the coral holobiont. Neither coral nor algal fractions displayed the full expression of the food source δ15N over a 60 d experimental period. The response of the skeletal δ15N value to the food δ15N was slower than the coral tissue, but this may have been caused by coarse sampling resolution coupled with a short experimental period. Using a mass-balance model, we determined that the corals must have been augmenting their rotifer diets by up to 50% with dissolved nitrogen from the water column. Using the δ15N of the combined food source (i.e. dissolved and rotifer nitrogen), we calculated tissue turnover rates of 87 d for the coral tissue and 111 d for the algal symbionts. These values dictate that the duration of any change in the δ15N of a coral’s N source needs to be greater than 3 mo to register its full magnitude in the tissue and skeletal nitrogen pools. This has implications for studies in which the host, symbiont and skeletal δ15N are used as a proxy for temporal changes in the source of nitrogen to coral reefs. Our results also support the notion of a bidirectional exchange of N between the coral and algae fractions, and provide estimations of the assimilation and excretion of N during heterotrophic feeding
A new pathway for hexavalent chromium formation in soil: Fire-induced alteration of iron oxides
No full textIron oxides are important pedogenic Cr(III)-bearing phases which experience high-temperature alteration via fire-induced heating of surface soil. In this study, we examine if heating-induced alteration of Cr(III)-substituted Fe oxides can potentially facilitate rapid high-temperature oxidation of solid-phase Cr(III) to hazardous Cr(VI). Synthetic Cr(III)-substituted ferrihydrite, goethite and hematite were heated up to 800 °C for 2 h. Corresponding heating experiments were also conducted on an unpolluted Ferrosol-type soil, which had a total Cr content of 220 mg kg−1, initially undetectable Cr(VI) and Fe speciation comprising a mixture of hematite, goethite and ferrihydrite (according to Fe K-edge EXAFS spectroscopy). Up to ∼50% of the initial Cr(III) was oxidised to Cr(VI) during heating of Cr(III)-substituted ferrihydrite and hematite, with the greatest extent of Cr(VI) formation occurring at 200–400 °C. In contrast, heating of Cr(III)-substituted goethite resulted in up to ∼100% of Cr(III) oxidizing to Cr(VI) as the temperature approached 800 °C. In the Ferrosol-type soil, heating at ≥400 °C also resulted in large amounts of Cr(VI) formation, with a maximum total Cr(VI) concentration of 77 mg kg−1 forming at 600 °C (equating to oxidation of ∼35% of the soil\u27s total Cr content). A relatively large portion (31–42%) of the total Cr(VI) which formed during heating of the soil was exchangeable, implying a high level of potential mobility and bioaccessibility. Overall, the results show that Cr(VI) forms rapidly via the oxidation of Fe oxide-bound Cr(III) at temperatures which occur in surface soils during fires. On this basis and given the frequency and extent of wild-fires around the world, we propose that fire-induced oxidation of Fe oxide-bound Cr(III) may represent a globally-significant pathway for the natural formation of hazardous Cr(VI) in surface soil
Mortality and cause of death of Australians on the autism spectrum
No full textFocused investigations regarding mortality rates, risk factors, and cause of death in autistic populations remain scarce. The present study used large linked datasets spanning 2001–2015 to report the rates and risk factors for mortality and cause of death in individuals on the autism spectrum (n = 35,929 age range 5–64) with and without concurrent intellectual disability (ID) in New South Wales, Australia. Mortality rates for those on the autism spectrum were 2.06 times that of the general population. Concurrent ID, epilepsy, mental health conditions, and chronic physical health conditions were associated with a higher risk of death for those on the spectrum, whereas demographic variables such as gender and socioeconomic status were not. A differing profile of top causes of death was found for autistic individuals relative to the general population, with “nervous system and sense disorders” and “injury and poisoning” being the top‐ranked causes for those on the spectrum. The findings alert the need for health promotion and management of concurrent physical and mental health conditions for those on the autism spectrum. There is also a need for better identification, diagnosis, and documentation of older adults on the autism spectrum
Antimony mobility in reducing environments: the effect of microbial iron(III)-reduction and associated secondary mineralization
No full textAntimony is an environmental contaminant, whose mobility in soils, sediments and groundwater systems is strongly influenced by interactions with Fe(III) oxide minerals. When exposed to reducing conditions, these minerals can undergo reductive dissolution via the activity of Fe(III)-reducing microorganisms, thereby potentially liberating previously retained Sb. In addition, microbial Fe(III)-reduction and the consequent production of Fe(II) can induce the formation of secondary Fe(III)- and Fe(II)-bearing minerals, which may alter the speciation and partitioning of Sb. In this study, we examined Sb behaviour during (1) the microbially-mediated reduction and transformation of Sb(V)-bearing ferrihydrite by the dissimilatory Fe(III)-reducing bacterium, Shewanella putrefaciens (strain CN32), and (2) during the associated abiotic Fe(II)-catalyzed transformation of Sb(V)-bearing ferrihydrite. Antimony K-edge XANES spectroscopy showed negligible reduction of Sb(V) to Sb(III) in both experiments, reflecting the redox stability of Sb(V) under these conditions. X-ray diffraction and Fe K-edge EXAFS spectroscopy revealed that both microbially-mediated Fe(II) production as well as the experimental addition of aqueous Fe(II) under abiotic conditions triggered rapid transformation of the initial ferrihydrite to feroxyhyte (δ′-FeOOH) and goethite (α-FeOOH). Goethite has been widely observed as a product of the Fe(II)-catalyzed transformation of ferrihydrite. However, the present study is the first to document the formation of feroxyhyte via this pathway, with feroxyhyte formation appearing to be favored by the presence of Sb(V). The formation of these secondary Fe(III) oxides was associated with substantial decreases in aqueous Sb concentrations and in the amount of surface-bound Sb (as defined via extractions with 1 M PO43−). This is consistent with the incorporation of Sb(V) into the newly formed feroxyhyte and goethite via substitution for Fe(III). The results of this study provide new perspectives on coupling between Sb geochemistry and Fe mineralogy by showing that microbial Fe(III)-reduction and associated secondary Fe(III)-oxide formation can help to immobilize Sb(V) in reducing environments
Assessing the readability and patient comprehension of rheumatology medicine information sheets: a cross-sectional Health Literacy Study
No full textObjectives: Patients are often provided with medicine information sheets (MIS). However, up to 60% of patients have low health literacy. The recommended readability level for health-related information is ≤grade 8. We sought to assess the readability of MIS given to patients by rheumatologists in Australia, the UK and Canada and to examine Australian patient comprehension of these documents.Design: Cross-sectional study.Setting: Community-based regional rheumatology practice.Participants: Random sample of patients attending the rheumatology practice.Outcome measures: Readability of MIS was assessed using readability formulae (Flesch Reading Ease formula, Simple Measure of Gobbledygook scale, FORCAST (named after the authors FORd, CAylor, STicht) and the Gunning Fog scale). Literal comprehension was assessed by asking patients to read various Australian MIS and immediately answer five simple multiple choice questions about the MIS.results: The mean (±SD) grade level for the MIS from Australia, the UK and Canada was 11.6±0.1, 11.8±0.1 and 9.7±0.1 respectively. The Flesch Reading Ease score for the Australian (50.8±0.6) and UK (48.5±1.5) MIS classified the documents as \u27fairly difficult\u27 to \u27difficult\u27. The Canadian MIS (66.1±1.0) were classified as \u27standard\u27. The five questions assessing comprehension were correctly answered by 9/21 patients for the adalimumab MIS, 7/11 for the methotrexate MIS, 6/28 for the non-steroidal anti-inflammatory MIS, 10/11 for the prednisone MIS and 13/24 for the abatacept MIS.Conclusions: The readability of MIS used by rheumatologists in Australia, the UK and Canada exceeds grade 8 level. This may explain why patient literal comprehension of these documents may be poor. Simpler, shorter MIS with pictures and infographics may improve patient comprehension. This may lead to improved medication adherence and better health outcomes
Hydrological drivers of carbon dioxide cycling from headwaters to the coastal ocean on a tropical island
No full textThis thesis investigates the hydrological drivers of carbon dioxide cycling from mountain headwaters to the coastal ocean in modified and unmodified systems on a tropical island (Bali, Indonesia). The central hypothesis is that a combination of rainfall and groundwater seepage drive aquatic CO2 fluxes. Chapter 1 provides a general review of the topic. Chapter 2 examines atmospheric CO2 fluxes in a reservoir and a tropical volcanic lake. The highest pCO2 occurred in the wet season in both systems. In the natural lake, the metabolism of surface water was an important driver of CO2 dynamics, while in the reservoir, groundwater seepage was the major CO2 driver. As the natural lake was a sink of atmospheric CO2 and the reservoir a source of CO2 to the atmosphere, future increases in reservoir construction may partially offset the natural lake CO2 sink. Chapter 3 examines carbon dynamics in a highly modified estuary. In the upper estuary atmospheric CO2 fluxes were five-fold that of the tidally dominated lower estuary, while the mountainous river atmospheric CO2 fluxes were negligible. The estuary source of CO2 to the atmosphere was comparable to high emission temperate estuaries and higher than the reported averages from tropical estuaries. Rainfall caused a delayed pCO2 response due to groundwater seepage entering the estuary. Chapter 4 examines the interconnectivity of mangrove forests, seagrasses and the coastal ocean in a tropical embayment with no river inputs. The CO2 source was associated with delayed groundwater inputs from the mangrove-dominated upper embayment, shifting to a CO2 sink in the lower seagrass-dominated embayment. Chapter 5 summarizes the thesis. Overall delayed groundwater seepage, as a result of episodic rainfall events, played an important role on carbon dynamics along the aquatic continuum. Modification of the tropical aquatic landscapes investigated, including drainage of mangroves, removal of seagrass beds, and construction of reservoirs has the potential to increase aquatic CO2 emissions to the atmosphere
The social and cultural role of food for Myanmar refugees in regional Australia: making place and building networks
No full textThe social role of food has sustained growing interest in recent times. These studies become even more meaningful to sociological discussions when the research participants have faced multiple levels of disadvantage based on immigration status, ethnicity, experience of trauma, language abilities, and geographic location. This research maps the social and cultural food journeys of people from Myanmar to the regional city of Coffs Harbour, Australia. This interdisciplinary study uses focused ethnography and participatory/collaborative research methods to document and analyse food experiences. The findings reveal a positive settlement story, one where differences and challenges have been overcome and a resilient community has utilised networks built to confidently mark out its place in a new home. The role of food in bringing together communities and individuals, has allowed these networks to be strengthened
Arsenic removal from aqueous solutions and groundwater using agricultural biowastes-derived biosorbents and biochar: a column-scale investigation
No full textIn this study, column-scale laboratory experiments were performed to evaluate the arsenic (As) removal efficiency of different agricultural biowastes-derived biosorbents (orange peel, banana peel, rice husk) and biochar, using As-containing solutions and As-contaminated groundwater. All the biosorbents and biochar efficiently removed (50-100%) As from groundwater (drinking well water). Arsenic removal potential of biosorbents varied with their type, As concentration, contact time, and As solution type. After 1 h, the As removal efficiency of all the biosorbents was 100%, 100% and 90% for 5, 10, and 50 µg/L As-contaminated groundwater samples, respectively; and it was 50%, 90%, and 90% for 10, 50, and 100 µg/L As solutions, respectively. After 2 h, all the biosorbents and biochar removed 100% As from aqueous solutions except for 100 µg/L As solution. This showed that the biosorbents and biochar could be used to reduce As contents below the WHO safe limit of As in drinking water (10 µg/L). Fourier transform infrared (FTIR) spectroscopy indicated possible role of various surface functional moieties on biosorbents/biochar surface to remove As from solution and groundwater. This pilot-scale column study highlights that the biosorbents and biochar can be effectively used in remediation of As-contaminated groundwater, although the soluble salts in groundwater increased after treatment with biochar