title: A review of current knowledge on toxic benthic freshwater cyanobacteria – Ecology, toxin production and risk management

authors: Quiblier, Catherine

subjects: toxic benthic cyanobacteria

abstract: Benthic cyanobacteria are found globally in plethora of environments. Although they have received less attention than their planktonic freshwater counterparts, it is now well established that they produce toxins and reports of their involvement in animal poisonings have increased markedly during the last decade. Most of the known cyanotoxins have been identified from benthic cyanobacteria including: the hepatotoxic microcystins, nodularins and cylindrospermopsins, the neurotoxic saxitoxins, anatoxin-a and homoanatoxin-a and dermatotoxins, such as lyngbyatoxin. In most countries, observations of toxic benthic cyanobacteria are fragmented, descriptive and in response to animal toxicosis events. Only a limited number of long-term studies have aimed to understand why benthic proliferations occur, and/or how toxin production is regulated. These studies have shown that benthic cyanobacterial blooms are commonly a mixture of toxic and non-toxic genotypes and that toxin concentrations can be highly variable spatially and temporally. Physiochemical parameters responsible for benthic proliferation vary among habitat type with physical disturbance (e.g., flow regimes, wave action) and nutrients commonly identified as important. As climatic conditions change and anthropogenic pressures on waterways increase, it seems likely that the prevalence of blooms of benthic cyanobacteria will increase. In this article we review current knowledge on benthic cyanobacteria: ecology, toxin-producing species, variables that regulate toxin production and bloom formation, their impact on aquatic and terrestrial organisms and current monitoring and management strategies. We suggest research needs that will assist in filling knowledge gaps and ultimately allow more robust monitoring and management protocols to be developed.

text: A review of current knowledge on toxic benthic freshwater cyanobacteria – Ecology, toxin production and risk management Benthic cyanobacteria are found globally in plethora of environments. Although they have received less attention than their planktonic freshwater counterparts, it is now well established that they produce toxins and reports of their involvement in animal poisonings have increased markedly during the last decade. Most of the known cyanotoxins have been identified from benthic cyanobacteria including: the hepatotoxic microcystins, nodularins and cylindrospermopsins, the neurotoxic saxitoxins, anatoxin-a and homoanatoxin-a and dermatotoxins, such as lyngbyatoxin. In most countries, observations of toxic benthic cyanobacteria are fragmented, descriptive and in response to animal toxicosis events. Only a limited number of long-term studies have aimed to understand why benthic proliferations occur, and/or how toxin production is regulated. These studies have shown that benthic cyanobacterial blooms are commonly a mixture of toxic and non-toxic genotypes and that toxin concentrations can be highly variable spatially and temporally. Physiochemical parameters responsible for benthic proliferation vary among habitat type with physical disturbance (e.g., flow regimes, wave action) and nutrients commonly identified as important. As climatic conditions change and anthropogenic pressures on waterways increase, it seems likely that the prevalence of blooms of benthic cyanobacteria will increase. In this article we review current knowledge on benthic cyanobacteria: ecology, toxin-producing species, variables that regulate toxin production and bloom formation, their impact on aquatic and terrestrial organisms and current monitoring and management strategies. We suggest research needs that will assist in filling knowledge gaps and ultimately allow more robust monitoring and management protocols to be developed.

year: 2013

title: Coupled flow-wave numerical model in assessing the impact of dredging on the morphology of Matakana Banks

authors: Ramli, Andi Yulianti

subjects: ebb-tidal delta

abstract: The short- and long-term impacts of dredging on the Matakana Banks ebb-tidal delta was investigated by numerical modelling using Delft3D. The model covered dredging locations inside Tauranga Harbour and the offshore areas around the Matakana Banks ebb-tidal delta, and was calibrated by an extensive field programme to measure hydrodynamic processes and sediment characteristics, and high resolution bathymetric surveys. The impacts of dredging was then investigated by modelling three different conditions: (1) before dredging started in 1968, using 1967 bathymetry; (2) the present situation using 2013 bathymetry with existing dredging and dumping; and (3) future scenarios using 2013 bathymetry with alternative offshore disposal locations. 
The field data and hydrodynamic model results showed that the ebb-tidal delta can be separated into two main regions that are dominated by tidal processes or wave processes. Overall, the wave influence becomes more dominant as the distance from the entrance channel (main ebb jet) increases, and vice versa for tidal processes. Sediment transport pathways were inferred using spatial patterns of erosion and accretion from bathymetric surveys and cross-sectional profiles along the shoreline. The pathways reflected the interactions between the identified wave and tide processes. 
A month-long time series of wave conditions were used to force a wave model coupled with the hydrodynamic model for the 2013 bathymetry to simulate the present day situation. The results showed that the sediment volume of the ebb-tidal delta fluctuated with tidal range; accretion occurred during neap tides and erosion during spring tides. To assess the long term impact, the morphological factor (morfac) tool in Delft3D was used. Morfac of 60 was applied for 12 days simulation time and the results will be presented in this paper

text: Coupled flow-wave numerical model in assessing the impact of dredging on the morphology of Matakana Banks The short- and long-term impacts of dredging on the Matakana Banks ebb-tidal delta was investigated by numerical modelling using Delft3D. The model covered dredging locations inside Tauranga Harbour and the offshore areas around the Matakana Banks ebb-tidal delta, and was calibrated by an extensive field programme to measure hydrodynamic processes and sediment characteristics, and high resolution bathymetric surveys. The impacts of dredging was then investigated by modelling three different conditions: (1) before dredging started in 1968, using 1967 bathymetry; (2) the present situation using 2013 bathymetry with existing dredging and dumping; and (3) future scenarios using 2013 bathymetry with alternative offshore disposal locations. 
The field data and hydrodynamic model results showed that the ebb-tidal delta can be separated into two main regions that are dominated by tidal processes or wave processes. Overall, the wave influence becomes more dominant as the distance from the entrance channel (main ebb jet) increases, and vice versa for tidal processes. Sediment transport pathways were inferred using spatial patterns of erosion and accretion from bathymetric surveys and cross-sectional profiles along the shoreline. The pathways reflected the interactions between the identified wave and tide processes. 
A month-long time series of wave conditions were used to force a wave model coupled with the hydrodynamic model for the 2013 bathymetry to simulate the present day situation. The results showed that the sediment volume of the ebb-tidal delta fluctuated with tidal range; accretion occurred during neap tides and erosion during spring tides. To assess the long term impact, the morphological factor (morfac) tool in Delft3D was used. Morfac of 60 was applied for 12 days simulation time and the results will be presented in this paper

year: 2015

title: Observations by and conversations with health workers and hospital personnel involved in transferring Maori patients and whānau to Waikato Hospital in Aotearoa New Zealand

authors: Masters-Awatere, Bridgette

subjects: Science & Technology

abstract: The predominant focus of Aotearoa New Zealand’s public health system on biomedical models of health has left little room for meaningful engagement with holistic indigenous approaches. Culturally appropriate provision and support are recognized for their relevance and importance during hospital transferals. Hospital staff involved in transfers to one of New Zealand’s trauma centers share their observations of whānau Māori engagement during an admission away from their home base. Sixteen key informants share their experiences, which are presented as strategies and challenges to whānau engagement. Three main themes highlight challenges within the health system that make it difficult for hospital staff to engage whānau in the desired ways and as often as both parties would like. Key informants described services and practices that are not designed with patients and their whānau in mind; instead they are designed by clinicians around the needs of administrative systems. As employees within the public health system, key informants felt powerless to challenge dominant settings. Nevertheless, employees managed to circumnavigate processes. Our findings highlight the need for continued decolonization and anti-racism work within public health settings.

text: Observations by and conversations with health workers and hospital personnel involved in transferring Maori patients and whānau to Waikato Hospital in Aotearoa New Zealand The predominant focus of Aotearoa New Zealand’s public health system on biomedical models of health has left little room for meaningful engagement with holistic indigenous approaches. Culturally appropriate provision and support are recognized for their relevance and importance during hospital transferals. Hospital staff involved in transfers to one of New Zealand’s trauma centers share their observations of whānau Māori engagement during an admission away from their home base. Sixteen key informants share their experiences, which are presented as strategies and challenges to whānau engagement. Three main themes highlight challenges within the health system that make it difficult for hospital staff to engage whānau in the desired ways and as often as both parties would like. Key informants described services and practices that are not designed with patients and their whānau in mind; instead they are designed by clinicians around the needs of administrative systems. As employees within the public health system, key informants felt powerless to challenge dominant settings. Nevertheless, employees managed to circumnavigate processes. Our findings highlight the need for continued decolonization and anti-racism work within public health settings.

year: 2020