Browsing by Author "Brown N"

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    Learning from population displacement in the Pacific: case study of the 2017-2018 eruption of Ambae volcano, Vanuatu. SWOT analysis and recommendations.
    (Joint Centre for Disaster Research, Massey University, 2020-11-04) Rovins J; Stewart C; Brown N
    The 2017-2018 eruption of Ambae volcano, Vanuatu, caused the entire population of the island (~11,700 people) to be evacuated off-island twice: firstly in October 2017, and then from the end of July 2018 until the end of October 2018, when the eruption ceased. This event presents a valuable opportunity to learn from a large-scale forced migration in a Pacific setting. Lessons from this event will advise and help to plan for future population displacements and forced migrations due to hazard and climate change events. For the first phase of this report, a review and analysis of the literature on internally displaced people was carried out, and used as the basis to design a questionnaire. Our field team visited the island of Santo, the destination for the majority of evacuees from Ambae, in February 2020, and carried out interviews with 42 evacuees, 26 female and 16 male, ranging in age from 21 to 82 over a four-day period. This report contains an event summary; a description of the research; a SWOT analysis; a discussion of key findings; recommendations; and an identification of future research needs.
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    Polyphosphate accumulation in microalgae and cyanobacteria: recent advances and opportunities for phosphorus upcycling.
    (Elsevier B.V., 2024-09-19) Plouviez M; Brown N; Blank L; Pratt C
    Phosphorus (P) must continuously be added to soils as it is lost in the food chain and via leaching. Unfortunately, the mining and import of P to produce fertiliser is unsustainable and costly. Potential solutions to the global issues of P rock depletion and pollution lie in microalgae and cyanobacteria. With an ability to intracellularly store P as polyphosphates, microalgae and cyanobacteria could provide the basis for removing P from water streams, thereby mitigating eutrophication, and even enabling P recovery as P-rich biomass. Metabolic engineering or changes in growing conditions have been demonstrated to improve P removal and recovery by triggering polyphosphates synthesis in the laboratory. This now needs to be replicated at full scale.
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    Polyphosphate synthesis is an evolutionarily ancient phosphorus storage strategy in microalgae
    (Elsevier B.V., 2023-06-02) Cliff A; Guieysse B; Brown N; Lockhart P; Dubreucq E; Plouviez M
    To assess the ubiquity of the potential for inorganic polyphosphate (polyP) synthesis in microalgae, we searched databases for algal homologues to the polyP polymerase VTC4 of Chlamydomonas reinhardtii. Homologues of this protein were found within >40 species of microalgae known to inhabit marine, freshwater, and terrestrial environments. Phylogenetic analysis demonstrated that these proteins were organized into clades aligning with their taxonomic relationships. These similarities and evolutionary relationships suggest that polyP synthesis represents an ancient ability that has evolved with species as the microalgal lineage has spread out over time. Based on these results and prior knowledge on P metabolism, C. reinhardtii, Chlorella vulgaris, Desmodesmus cf. armatus, Gonium pectorale, and Microcystis aeruginosa were further tested in bioassays known to trigger the synthesis of polyP within dense granules, by addition of P following a period of P depletion. While the cellular P content of C. reinhardtii, G. pectorale, M. aeruginosa, and D. cf. armatus increased to similar maxima, ranging from 2.6 ± 0.5 % to 3.6 ± 1.3 % 24 h after P repletion, P content only reached 1.2 ± 0.2 % in C. vulgaris, suggesting a lesser ability to accumulate polyP than the strains of the other species. Models of predicted VTC4 proteins were generated from the four eukaryotic species tested and showed that the microalgae share the conserved VTC catalytic core and SPX phosphate-sensing domains found in the yeast VTC4 proteins. This confirms the role of microalgal VTC4 as polyP polymerase and suggests a similar regulation of VTC4 proteins to the one described in yeast. Further work is now needed to uncover the assembly of the microalgal VTC complex and its regulation. A deeper study of the microalgal VTC structure could also help to understand whether differences in VTC structures can explain observed differences in P accumulation kinetics.