Journal Articles

Permanent URI for this collectionhttps://mro.massey.ac.nz/handle/10179/7915

Browse

Filters

2019 - 201912020 - 20254

Settings

Subject: search.filters.subject.Rivers

Search Results

Now showing 1 - 5 of 5
  • Thumbnail Image
    Item
    Genomic epidemiology of extended-spectrum beta-lactamase-producing Escherichia coli from humans and a river in Aotearoa New Zealand.
    (Microbiology Society, 2025-01-10) Gray HA; Biggs PJ; Midwinter AC; Rogers LE; Fayaz A; Akhter RN; Burgess SA
    In Aotearoa New Zealand, urinary tract infections in humans are commonly caused by extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli. This group of antimicrobial-resistant bacteria are often multidrug resistant. However, there is limited information on ESBL-producing E. coli found in the environment and their link with human clinical isolates. In this study, we examined the genetic relationship between environmental and human clinical ESBL-producing E. coli and isolates collected in parallel within the same area over 14 months. Environmental samples were collected from treated effluent, stormwater and multiple locations along an Aotearoa New Zealand river. Treated effluent, stormwater and river water sourced downstream of the treated effluent outlet were the main samples that were positive for ESBL-producing E. coli (7/14 samples, 50.0%; 3/6 samples, 50%; and 15/28 samples, 54%, respectively). Whole-genome sequence comparison was carried out on 307 human clinical and 45 environmental ESBL-producing E. coli isolates. Sequence type 131 was dominant for both clinical (147/307, 47.9%) and environmental isolates (11/45, 24.4%). Only one ESBL gene was detected in each isolate. Among the clinical isolates, the most prevalent ESBL genes were bla CTX-M-27 (134/307, 43.6%) and bla CTX-M-15 (134/307, 43.6%). Among the environmental isolates, bla CTX-M-15 (28/45, 62.2%) was the most prevalent gene. A core SNP analysis of these isolates suggested that some strains were shared between humans and the local river. These results highlight the importance of understanding different transmission pathways for the spread of ESBL-producing E. coli.
  • Thumbnail Image
    Item
    Incorporating hydrology into climate suitability models changes projections of malaria transmission in Africa.
    (Springer Nature Limited, 2020-08-28) Smith MW; Willis T; Alfieri L; James WHM; Trigg MA; Yamazaki D; Hardy AJ; Bisselink B; De Roo A; Macklin MG; Thomas CJ
    Continental-scale models of malaria climate suitability typically couple well-established temperature-response models with basic estimates of vector habitat availability using rainfall as a proxy. Here we show that across continental Africa, the estimated geographic range of climatic suitability for malaria transmission is more sensitive to the precipitation threshold than the thermal response curve applied. To address this problem we use downscaled daily climate predictions from seven GCMs to run a continental-scale hydrological model for a process-based representation of mosquito breeding habitat availability. A more complex pattern of malaria suitability emerges as water is routed through drainage networks and river corridors serve as year-round transmission foci. The estimated hydro-climatically suitable area for stable malaria transmission is smaller than previous models suggest and shows only a very small increase in state-of-the-art future climate scenarios. However, bigger geographical shifts are observed than with most rainfall threshold models and the pattern of that shift is very different when using a hydrological model to estimate surface water availability for vector breeding.
  • Thumbnail Image
    Item
    Freshwater invertebrate responses to fine sediment stress: A multi-continent perspective
    (John Wiley and Sons Ltd, 2024-01) McKenzie M; Brooks A; Callisto M; Collins AL; Durkota JM; Death RG; Jones JI; Linares MS; Matthaei CD; Monk WA; Murphy JF; Wagenhoff A; Wilkes M; Wood PJ; Mathers KL
    Excessive fine sediment (particles <2 mm) deposition in freshwater systems is a pervasive stressor worldwide. However, understanding of ecological response to excess fine sediment in river systems at the global scale is limited. Here, we aim to address whether there is a consistent response to increasing levels of deposited fine sediment by freshwater invertebrates across multiple geographic regions (Australia, Brazil, New Zealand and the UK). Results indicate ecological responses are not globally consistent and are instead dependent on both the region and the facet of invertebrate diversity considered, that is, taxonomic or functional trait structure. Invertebrate communities of Australia were most sensitive to deposited fine sediment, with the greatest rate of change in communities occurring when fine sediment cover was low (below 25% of the reach). Communities in the UK displayed a greater tolerance with most compositional change occurring between 30% and 60% cover. In both New Zealand and Brazil, which included the most heavily sedimented sampled streams, the communities were more tolerant or demonstrated ambiguous responses, likely due to historic environmental filtering of invertebrate communities. We conclude that ecological responses to fine sediment are not generalisable globally and are dependent on landscape filters with regional context and historic land management playing important roles.
  • Thumbnail Image
    Item
    Origin and Fate of Vanadium in the Hazeltine Creek Catchment following the 2014 Mount Polley Mine Tailings Spill in British Columbia, Canada
    (American Chemical Society, Washington, 2019-04-16) Hudson-Edwards KA; Byrne P; Bird G; Brewer PA; Burke IT; Jamieson HE; Macklin MG; Williams RD
    Results from the analysis of aqueous and solid-phase V speciation within samples collected from the Hazeltine Creek catchment affected by the August 2014 Mount Polley mine tailings dam failure in British Columbia, Canada, are presented. Electron microprobe and X-ray absorption near-edge structure (XANES) analysis found that V is present as V3+ substituted into magnetite and V3+ and V4+ substituted into titanite, both of which occur in the spilled Mount Polley tailings. Secondary Fe oxyhydroxides forming in inflow waters and on creek beds have V K-edge XANES spectra exhibiting E1/2 positions and pre-edge features consistent with the presence of V5+ species, suggesting sorption of this species on these secondary phases. PHREEQC modeling suggests that the stream waters mostly contain V5+ and the inflow and pore waters contain a mixture of V3+ and V5+. These data, and stream, inflow, and pore water chemical data, suggest that dissolution of V(III)-bearing magnetite, V(III)- and V(IV)-bearing titanite, V(V)-bearing Fe(-Al-Si-Mn) oxhydroxides, and V-bearing Al(OH)3 and/or clay minerals may have occurred. In the circumneutral pH environment of Hazeltine Creek, elevated V concentrations are likely naturally attenuated by formation of V(V)-bearing secondary Fe oxyhydroxide, Al(OH)3, or clay mineral colloids, suggesting that the V is not bioavailable. A conceptual model describing the origin and fate of V in Hazeltine Creek that is applicable to other river systems is presented.
  • Thumbnail Image
    Item
    Nutrient criteria to achieve New Zealand's riverine macroinvertebrate targets
    (PeerJ, Inc, 2021) Canning AD; Joy MK; Death RG; Brauns M
    Waterways worldwide are experiencing nutrient enrichment from population growth and intensive agriculture, and New Zealand is part of this global trend. Increasing fertilizer in New Zealand and intensive agriculture have driven substantial water quality declines over recent decades. A recent national directive has set environmental managers a range of riverine ecological targets, including three macroinvertebrate indicators, and requires nutrient criteria be set to support their achievement. To support these national aspirations, we use the minimization-of-mismatch analysis to derive potential nutrient criteria. Given that nutrient and macroinvertebrate monitoring often does not occur at the same sites, we compared nutrient criteria derived at sites where macroinvertebrates and nutrients are monitored concurrently with nutrient criteria derived at all macroinvertebrate monitoring sites and using modelled nutrients. To support all three macroinvertebrate targets, we suggest that suitable nutrient criteria would set median dissolved inorganic nitrogen concentrations at ~0.6 mg/L and median dissolved reactive phosphorus concentrations at ~0.02 mg/L. We recognize that deriving site-specific nutrient criteria requires the balancing of multiple values and consideration of multiple targets, and anticipate that criteria derived here will help and support these environmental goals.