Faculty of Health and Environmental Sciences (Te Ara Hauora A Pūtaiao)

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https://hdl.handle.net/10292/10759
Faculty of Health and Environmental Sciences - Te Ara Hauora A Pūtaiao encompasses the
  • School of Clinical Sciences - Te Kura Mātai Haumanu
  • School of Science - Te Kura Pūtaiao
  • School of Sport and Recreation - Te Kura Hākinakina

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    Browsing Faculty of Health and Environmental Sciences (Te Ara Hauora A Pūtaiao) by Subject "03 Chemical Sciences"

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      Ecosystem Integrity of Active Sand Dunes: A Case Study to Implement and Test the SEEA-EA Global Standard, From Aotearoa New Zealand
      (Elsevier BV, 2023-05-01) Ryan, C; Case, BS; Bishop, CD; Buckley, HL
      Biodiversity and ecosystem functions are deteriorating worldwide, and there is an urgent need to reverse these declines and set ecosystems on a path to recovery. Effective monitoring, including a fit for purpose indicator framework, is essential to track progress towards targets but, as yet there is no universal framework that delivers timely data on biodiversity and ecosystem change. Ecosystem integrity is a unifying concept that refers to the capacity of an ecosystem to be resilient to natural or anthropogenic perturbations, and to maintain characteristic species composition, structure, functioning and self-organisation over time within a natural range of variability. Using a case study which can be generalised to international contexts, we implement and test a new global standard for the assessment, monitoring and ranking of ecosystem integrity of active sand dunes in Aotearoa New Zealand.
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      Interactive Effects of Elevated Temperature and Photobacterium swingsii Infection on the Survival and Immune Response of Marine Mussels (Perna canaliculus): A Summer Mortality Scenario
      (Elsevier BV, 2024-02-03) Azizan, Awanis; Venter, Leonie; Zhang, Jingjing; Young, Tim; Ericson, Jessica A; Delorme, Natalí J; Ragg, Norman LC; Alfaro, Andrea C
      The New Zealand Greenshell™ mussel (Perna canaliculus) is an economically important aquaculture species. Prolonged increases in seawater temperature above mussel thermotolerance ranges pose a significant threat to mussel survival and health, potentially increasing susceptibility to bacterial infections. Using challenge experiments, this study examined the combined effects of increased seawater temperature and bacterial (Photobacterium swingsii) infection on animal survival, haemocyte and biochemical responses of adult mussels. Mussels maintained at three temperatures (16, 20 and 24 °C) for seven days were either not injected (control), injected with sterile marine broth (injection control) or P. swingsii (challenged with medium and high doses) and monitored daily for five days. Haemolymph and tissue samples were collected at 24, 48, 72, 96, 120 h post-challenge and analysed to quantify bacterial colonies, haemocyte responses and biochemical responses. Mussels infected with P. swingsii exhibited mortalities at 20 and 24 °C, likely due to a compromised immune system, but no mortalities were observed when temperature was the only stressor. Bacterial colony counts in haemolymph decreased over time, suggesting bacterial clearance followed by the activation of immune signalling pathways. Total haemocyte counts and viability data supports haemocyte defence functions being stimulated in the presence of high pathogen loads at 24 °C. In the gill tissue, oxidative stress responses, measured as total antioxidant capacity and malondialdehyde (MDA) levels, were higher in infected mussels (compared to the controls) after 24h and 120h post-challenge at the lowest (16 °C) and highest temperatures (24 °C), indicating the presence of oxidative stress due to temperature and pathogen stressors. Overall, this work confirms that Photobacterium swingsii is pathogenic to P. canaliculus and indicates that mussels may be more vulnerable to bacterial pathogens under conditions of elevated temperature, such as those predicted under future climate change scenarios.
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