Response of macroinvertebrate communities to seasonal hydrologic changes in three sub-tropical Australian streams.

In the Australian sub-tropics, seasonal changes in hydrology can influence abiotic conditions, and consequently, the biota. Several methods of macroinvertebrate analyses, including the use of taxonomic groupings, are used to ascertain information regarding stream biodiversity and health. The use of biological traits to group and analyse macroinvertebrate communities, however, may provide a better picture of stream health, particularly in ephemeral streams. To address whether this is the case, three ephemeral systems in the lower Fitzroy catchment, Central Queensland, Australia, were studied over an 18-month period. A total of 69 macroinvertebrate families from 14 orders were collected in 128 samples. Taxonomic analysis indicated there was a range of habitat preferences within groups characterized by a large proportion of tolerant and generalist taxa. The macroinvertebrate communities were categorised into biological trait groups, with a number of predator families found during all flow regimes. A general pattern of Gatherer > Predator > Grazer > Shredder > Filterer was observed. This study provides a clear pattern of the biological traits present during variable flow and could be used as a framework for future stream health modelling. A trait-specific management tool for assessing freshwaters has not yet been adopted in global management protocols and would require both a more definitive understanding of patterns during different flow periods and an internationally recognised set of trait nomenclature.

Humic acid decreases acute toxicity and ventilation frequency in eastern rainbowfish (Melanotaenia splendida splendida) exposed to acid mine drainage.

Acid mine drainage (AMD) is a global problem leading to the acidification of freshwaters, as well as contamination by heavy metals. The ability of humic substances (HS) such as humic acid (HA) to decrease toxicity of heavy metals is widely known, whereas limited studies have examined the ability of HS to decrease toxicity linked with multiple stressors such as those associated with AMD. This study investigated the ability of HA to decrease acute toxicity defined as morbidity and ventilation frequency (measured via the time elapsed for ten operculum movements) in eastern rainbowfish (Melanotaenia splendida splendida) exposed to the multiple stressors of AMD-driven heavy metal concentrations, together with low pH. Water from the Mount Morgan open pit (a now closed gold and copper mine site), located at Mount Morgan, Central Queensland, Australia, was used as the AMD source. Fish were exposed to zero per cent (pH 7.3), two per cent (pH 6.7), three per cent (pH 5.7) and four per cent (pH 4.6) AMD in the presence of 0, 10 and 20mg/L Aldrich Humic Acid (AHA) over 96h. HA was shown to significantly decrease the acute toxicity of AMD and its adverse effects on ventilation frequency. These results are important in showing that HA can influence toxicity of metal mixtures and low pH, thus indicating a potential role for HA in decreasing toxicity of multiple environmental stressors more widely, and possible value as a rehabilitation aid.

Humic substances of varying types increase survivorship of the freshwater shrimp Caridina sp. D to acid mine drainage.

Differences relating to the ability of various types of humic substances (HS) to influence toxicity of pollutants have been reported in the literature, but there still remains a gap in understanding whether various HS will have the same influence on the toxicity of acid mine drainage (AMD). This study investigated differences in the ability of Aldrich humic acid (AHA), Suwannee River humic acid and Suwannee River fulvic acid to decrease toxicity of AMD to the freshwater shrimp (Caridina sp. D). Toxicity tests were conducted over 96 h and used Mount Morgan open pit water as source of AMD and Dee River water as control/diluents. Concentrations of 0-4 % AMD at 0 mg/L HS, 10 mg/L AHA, 10 mg/L Suwannee River humic acid and 10 mg/L Suwannee River fulvic acid were used. Significantly higher survival of shrimp was recorded in the HS treatments compared with the treatment containing no HS. No significant differences were found among HS type. HS considerably increased LC50 values irrespective of type, from 1.29 (0 mg/L HS) to 2.12 % (AHA); 2.19 (Suwannee River humic acid) and 2.22 % (Suwannee River fulvic acid). These results support previous work that HS decrease the toxicity of AMD to freshwater organisms, but with the novel finding that this ability occurs irrespective of HS type. These results increase the stock of knowledge regarding HS and may contribute to a possible remediation option for AMD environments.

Identifying impacts & adaptation strategies for tropical fruit farms affected by extreme weather events in sub-tropical Australia: Stakeholders' insights.

Extreme weather events (EWEs) have significant effects on the productivity, profitability and sustainability of agricultural enterprises and supply chains. Australia is acknowledged as a highly susceptible developed country in relation to experiencing impacts from global climate change. Particularly, the Central Queensland (CQ) region has experienced several recent severe weather events which has made stakeholders worried about the financial resilience and sustainability of their businesses along with the farmers. Although various Australian research has explored the biophysical effects of extreme weather on pome and citrus fruits, very little is known about the business impacts of EWEs on tropical fruits, and how the perceptions of stakeholders can play significant roles in constructing and implementing policies relevant to the tropical fruit farming sector. To fill this gap, this study explored stakeholder insights relating to the impacts of EWEs and relevant adaptation strategies used in tropical fruit farming businesses in sub-tropical Australia. A qualitative research approach was undertaken, involving in-depth interviews with key stakeholders from the tropical fruit farming supply chain, with data being analysed by thematic content analysis. Stakeholders indicated that in the previous five years, EWEs had impacted tropical fruit farming businesses and their related support industries and organisations in multiple ways. This study revealed that farmers' lack of knowledge about available adaptation options, amongst other things, are obstacles preventing the industry from becoming more resilient. Several steps were identified to improve the speed and effectiveness of adaptation at the farm level, including further strategic planning and collaboration amongst state government, local government, farmers and associated industry parties; as well as the importance of farmers being self-prepared for future EWEs. To achieve the latter, stakeholders noted that farmers required industry-level support, including training, tools, and technologies. These findings will be of interest for fruit farming industry stakeholders, policy makers and relevant researchers, particularly for the many tropical coastal communities across the world, now finding themselves being impacted by EWEs.

Interpreting the possible ecological role(s) of cyanotoxins: compounds for competitive advantage and/or physiological aide?

To date, most research on freshwater cyanotoxin(s) has focused on understanding the dynamics of toxin production and decomposition, as well as evaluating the environmental conditions that trigger toxin production, all with the objective of informing management strategies and options for risk reduction. Comparatively few research studies have considered how this information can be used to understand the broader ecological role of cyanotoxin(s), and the possible applications of this knowledge to the management of toxic blooms. This paper explores the ecological, toxicological, and genetic evidence for cyanotoxin production in natural environments. The possible evolutionary advantages of toxin production are grouped into two main themes: That of "competitive advantage" or "physiological aide". The first grouping illustrates how compounds produced by cyanobacteria may have originated from the need for a cellular defence mechanism, in response to grazing pressure and/or resource competition. The second grouping considers the contribution that secondary metabolites make to improved cellular physiology, through benefits to homeostasis, photosynthetic efficiencies, and accelerated growth rates. The discussion also includes other factors in the debate about possible evolutionary roles for toxins, such as different modes of exposures and effects on non-target (i.e., non-competitive) species. The paper demonstrates that complex and multiple factors are at play in driving evolutionary processes in aquatic environments. This information may provide a fresh perspective on managing toxic blooms, including the need to use a "systems approach" to understand how physico-chemical conditions, as well biological stressors, interact to trigger toxin production.

Humic substances increase survival of freshwater shrimp Caridina sp. D to acid mine drainage.

Humic substances (HS) are known to decrease the toxicity of heavy metals to aquatic organisms, and it has been suggested that they can provide buffering protection in low pH conditions. Despite this, little is known about the ability for HS to increase survival to acid mine drainage (AMD). In this study, the ability of HS to increase survival of the freshwater shrimp (Caridina sp. D sensu Page et al. in Biol Lett 1:139-142, 2005) to acid mine drainage was investigated using test waters collected from the Mount Morgan open pit in Central Queensland with the addition of Aldrich humic acid (AHA). The AMD water from the Mount Morgan open pit is highly acidic (pH 2.67) as well as contaminated with heavy metals (1780 mg/L aluminum, 101 mg/L copper [Cu], 173 mg/L manganese, 51.8 mg/L zinc [Zn], and 51.8 mg/L iron). Freshwater shrimp were exposed to dilutions in the range of 0.5 % to 5 % AMD water with and without the addition of 10 or 20 mg/L AHA. In the absence of HS, all shrimp died in the 2.5 % AMD treatment. In contrast, addition of HS increased survival in the 2.5 % AMD treatment by ≤66 % as well as significantly decreased the concentration of dissolved Cu, cobalt, cadmium, and Zn. The decreased toxicity of AMD in the presence of HS is likely to be due to complexation and precipitation of heavy metals with the HS; it is also possible that HS caused changes to the physiological condition of the shrimp, thus increasing their survival. These results are valuable in contributing to an improved understanding of potential role of HS in ameliorating the toxicity of AMD environments.

Horticulture producer's willingness to participate in contract-based supply chain coordination: A case study from Queensland (Australia).

Product export provides an option for horticulture producers in Queensland (Australia) to diversify their market and increase returns from production. Vertical supply chain coordination in the form of contract-based marketing agreements between producers and export agents/distributors could facilitate increased export. The aim of this study was to investigate the willingness of horticulture producers to participate in export focused contract-based marketing agreements. To achieve this aim, a survey including a discrete choice experiment was conducted. The results from a mixed logit model and a latent class model suggest that there are three clusters of producers: a) the export interested, b) the likely risk averse, and c) those well established in the domestic markets. Only producers in group a) expressed a preference for contract-based export marketing agreements. These producers appear to be younger, already have some export experience, and have a relatively high level of collaboration in their product supply chains. Producers in groups b) and c) expressed an interest in stronger coordination within the domestic retail sector, potentially in the form of contract farming. Prices of produce and potential higher production costs are determinants identified by all producer groups as important for their decision-making about changes to their supply chain.

The Prospective Implementation of the 2015 ATA Guidelines and Modified ATA Recurrence Risk Stratification System for Treatment of Differentiated Thyroid Cancer in a Canadian Tertiary Care Referral Setting.

Objective: To present clinical outcomes of the prospective implementation of the 2015 American Thyroid Association (ATA) guidelines for the management of thyroid nodules and differentiated thyroid cancer (DTC) using the modified ATA recurrence risk (RR) stratification system. Methods: We prospectively analyzed 612 patients with DTC treated between April 2017 and December 2021 in Calgary, Alberta. Each patient was prospectively assigned a modified ATA RR and American Joint Committee Cancer 8th edition stage. Initial risk stratification and consideration of the 2015 ATA guidelines guided surgical management as well as the indication for and dose of radioiodine (RAI) and other adjuvant therapies. Patients were assessed for their response to treatment (RTT) at 2-years postoperatively. Results: There were 479 patients who had 2-year follow-up data and were included in the study. Of these patients, there were 253 (53%) low-, 129 (27%) intermediate-, and 97 (20%) high-RR patients. Of these, 227 patients (47%) underwent total thyroidectomy (TTX) plus RAI, 178 (37%) underwent TTX only, and 74 (16%) underwent lobectomy. The RTT at 2 years was excellent for 89% (66) of patients with lobectomy, 84% (149) for TTX only, and 53% (121) for TTX plus RAI. Among 253 patients who were deemed low RR, 85% (216) had excellent RTT, 13% (32) indeterminate RTT, 2% (4) biochemical incomplete RTT, and 1 patient had structural incomplete RTT. The intermediate RR group had the following RTT outcomes: 64% (83) excellent, 23% (30) indeterminate, 6% (7) biochemical incomplete, and 7% (9) structural incomplete. The high RR group had the worst RTT outcomes, with 38% (37) excellent, 19% (18) indeterminate, 10% (10) biochemical incomplete, and 33% (32) structural incomplete RTT. Conclusions: The 2015 ATA RR stratification system is useful for predicting disease status at 2-year post-treatment in patients with DTC. The 2015 ATA guidelines and modified ATA RR stratification treatment recommendations may reduce thyroid cancer overtreatment by including lobectomy as a definitive treatment option for low-risk thyroid cancers and selective use of RAI for intermediate and high-risk patients.

Cylindrospermopsin: a decade of progress on bioaccumulation research.

Cylindrospermopsin (CYN) is rapidly being recognised as one of the most globally important of the freshwater algal toxins. The ever-expanding distribution of CYN producers into temperate zones is heightening concern that this toxin will represent serious human, as well as environmental, health risks across many countries. Since 1999, a number of studies have demonstrated the ability for CYN to bioaccumulate in freshwater organisms. This paper synthesizes the most current information on CYN accumulation, including notes on the global distribution of CYN producers, and a précis of CYN's ecological and human effects. Studies on the bioaccumulation of CYN are systematically reviewed, together with an analysis of patterns of accumulation. A discussion on the factors influencing bioaccumulation rates and potential is also provided, along with notes on detection, monitoring and risk assessments. Finally, key gaps in the existing research are identified for future study.

Cyanobacteria breakthrough: Effects of Limnothrix redekei contamination in an artificial bank filtration on a regional water supply.

Mitigation of cyanobacterial or "blue-green algal" blooms is a challenging task for water managers across Australia. In the present study, a regional drinking water source (located in Central Queensland) was studied to identify the potential risks posed by cyanobacteria. Data were collected from the drinking water source (a lagoon) as well as the drinking water supply infrastructure, at monthly intervals between September 2012 and December 2014. In March 2013 there was an extreme rainfall event where floodwaters infiltrated the water supply without passing through bank filtration. The floodwaters also compromised the bank filtration via erosion. The pump well and bank filtration system were subsequently upgraded/maintained in May 2013. Results showed that following the extreme event and infrastructure upgrade, two distinct Limnothrix redekei blooms microscopically identified, were detected in the drinking water supply chain. Further investigations indicated that the species was also present in the pump well infrastructure, a dark environment, growing on the surface of the newly installed pump well cement pipe. After observing the occurrence and habitat niche of this species during the present study, a suggestion was made to minimise cyanobacterial contamination and proliferation within the water supply chain infrastructure. The preliminary proposal is to use clean sand on the sub-surface layer of the bank filtration, complemented with biologically active sand as a surface cap. Furthermore, the culturing techniques reported in this study can potentially be used to optimize assessment for Limnothrix redekei populations surrounding water extraction points.

Autoimmune pancreatitis associated with renal lesions mimicking metastatic tumours.

Autoimmune pancreatitis is a chronic inflammatory disorder that is often misdiagnosed as pancreatic cancer. Since autoimmune pancreatitis is benign and responds to steroid management, it is important to diagnose it to avoid unnecessary surgical intervention. We describe a novel case of IgG4-associated autoimmune pancreatitis presenting with tubulointerstitial nephritis as renal lesions mimicking metastatic tumours but with no change in renal function.

Influence of Aldrich humic acid and metal precipitates on survivorship of mayflies (Atalophlebia spp.) to acid mine drainage.

Humic substances (HS) have been shown to decrease the toxicity of environmental stressors, but knowledge of their ability to influence the toxicity of multiple stressors such as metal mixtures and low pH associated with acid mine drainage (AMD) is still limited. The present study investigated the ability of HS to decrease toxicity of AMD to mayflies (Atalophlebia spp.). The AMD was collected from the Mount Morgan (Mount Morgan, Queensland, Australia) open pit. Mayflies were exposed to concentrations of AMD at 0%, 1%, 2%, 3%, and 4% in the presence of 0 mg/L, 10 mg/L, and 20 mg/L Aldrich humic acid (AHA). A U-shaped response was noted in all AHA treatments, with higher rates of mortality recorded in the 2% and 3% dilutions compared with 4%. This result was linked with increased precipitates in the lower concentrations. A follow-up trial showed significantly higher concentrations of precipitates in the 2% and 3% AMD dilutions in the 0 mg/L AHA treatment and higher precipitates in the 2% AMD, 10 mg/L and 20 mg/L AHA, treatments. Humic substances were shown to significantly increase survival of mayflies exposed to AMD by up to 50% in the 20 mg/L AHA treatment. Humic substances may have led to increased survival after AMD exposure through its ability to influence animal physiology and complex heavy metals. These results are valuable in understanding the ability of HS to influence the toxicity of multiple stressors.

The double-edged sword of humic substances: contrasting their effect on respiratory stress in eastern rainbow fish exposed to low pH.

High amounts of humic substances (HS) are commonly found in natural acidic waterways and have been suggested to offer some protection against low pH. This study investigated the ability of HS to decrease respiratory stress in eastern rainbowfish (Melanotaenia splendida splendida) exposed to decreases in pH (range of 7-3.5) in soft and hard water. Repeated measures ANOVA revealed a significant difference in respiration (time taken for ten operculum movements) between pH and HS treatments, with a significant interaction between pH and HS present in 5/6 trials. Respiratory stress was shown to increase with increasing acidity, but significantly decreased in treatments with HS (10 and 20 mg/L) compared to those without. The fish exposed to pH treatments without HS also displayed increased hyperactivity, larger operculum movements and increased mucous production. Increased morbidity was shown in HS treatments at pH 3.5 (soft water) and at pH 4 (hard water) compared to treatment without HS. This indicates that HS is helpful in ameliorating the effects of decreased pH on respiration at sublethal pH levels; however, as pH decreases further, it seems that HS increases the toxicity (morbidity) of the low pH.