title: Within-mat variability in anatoxin-a and homoanatoxin-a production among benthic Phormidium (cyanobacteria) strains.

authors: Wood, Susanna A.

subjects: 16S rRNA gene sequence

abstract: Benthic Phormidium mats can contain high concentrations of the neurotoxins anatoxin-a and homoanatoxin-a. However, little is known about the co-occurrence of anatoxin-producing and non-anatoxin-producing strains within mats. There is also no data on variation in anatoxin content among toxic genotypes isolated from the same mat. In this study, 30 Phormidium strains were isolated from 1 cm(2) sections of Phormidium-dominated mats collected from three different sites. Strains were grown to stationary phase and their anatoxin-a, homoanatoxin-a, dihydroanatoxin-a and dihydrohomoanatoxin-a concentrations determined using liquid chromatography-mass spectrometry. Each strain was characterized using morphological and molecular (16S rRNA gene sequences) techniques. Eighteen strains produced anatoxin-a, dihydroanatoxin-a or homoanatoxin-a. Strains isolated from each mat either all produced toxins, or were a mixture of anatoxin and non-anatoxin-producing genotypes. Based on morphology these genotypes could not be separated. The 16S rRNA gene sequence comparisons showed a difference of at least 17 nucleotides among anatoxin and non-anatoxin-producing strains and these formed two separate sub-clades during phylogenetic analysis. The total anatoxin concentration among toxic strains varied from 2.21 to 211.88 mg kg(-1) (freeze dried weight), representing a 100 fold variation in toxin content. These data indicate that both the relative abundance of anatoxin and non-anatoxin-producing genotypes, and variations in anatoxin producing capability, can influence the overall toxin concentration of benthic Phormidium mat samples.

text: Within-mat variability in anatoxin-a and homoanatoxin-a production among benthic Phormidium (cyanobacteria) strains. Benthic Phormidium mats can contain high concentrations of the neurotoxins anatoxin-a and homoanatoxin-a. However, little is known about the co-occurrence of anatoxin-producing and non-anatoxin-producing strains within mats. There is also no data on variation in anatoxin content among toxic genotypes isolated from the same mat. In this study, 30 Phormidium strains were isolated from 1 cm(2) sections of Phormidium-dominated mats collected from three different sites. Strains were grown to stationary phase and their anatoxin-a, homoanatoxin-a, dihydroanatoxin-a and dihydrohomoanatoxin-a concentrations determined using liquid chromatography-mass spectrometry. Each strain was characterized using morphological and molecular (16S rRNA gene sequences) techniques. Eighteen strains produced anatoxin-a, dihydroanatoxin-a or homoanatoxin-a. Strains isolated from each mat either all produced toxins, or were a mixture of anatoxin and non-anatoxin-producing genotypes. Based on morphology these genotypes could not be separated. The 16S rRNA gene sequence comparisons showed a difference of at least 17 nucleotides among anatoxin and non-anatoxin-producing strains and these formed two separate sub-clades during phylogenetic analysis. The total anatoxin concentration among toxic strains varied from 2.21 to 211.88 mg kg(-1) (freeze dried weight), representing a 100 fold variation in toxin content. These data indicate that both the relative abundance of anatoxin and non-anatoxin-producing genotypes, and variations in anatoxin producing capability, can influence the overall toxin concentration of benthic Phormidium mat samples.

year: 2012-10

title: Characterisation, potential toxicity and fate of storm water run-off from log storage areas of the Port of Tauranga.

authors: Culliford, David Paul

subjects: Stormwater

abstract: Stormwater run-off from industrial sources can impact the receiving environment by the discharge of toxic substances, nutrients, sediments or fresh water (in marine environments). The Port of Tauranga is New Zealand’s largest by cargo volume with untreated logs being one of the major exports. The port stores logs totalling up to 300,000 m3 with an average residency time of 18 days. Runoff from log storage areas can cause toxicity to aquatic life due to low pH, high organic solids content and associated BOD, and chemicals leached from timber such as resin acids. Metals and PAH’s from heavy vehicles and other machinery can also be present. 
At the port, stormwater collects from the storage areas into slot drains and is screened for larger particulates in screening chambers before discharging into Tauranga Harbour. Large rainfall events produce a visible, highly coloured plume extending across the main harbour channel. 
This study looks at compounds within the stormwater runoff and associated marine water samples and the toxicology of the effluent. It then focusses on the gradients of compounds found in sediments and biota in relation to the main discharge sources. This is followed with a more specific investigation of the bioaccumulation of resin acids in resident and transplanted mussels. It concludes with a comparison of low intertidal species assemblages within and outside the influence of the stormwater plume.
Findings indicate that there are high levels of wood derived chemicals in the stormwater runoff and a gradient of quantities of these can be detected in nearby sediments, decreasing with distance from the discharge point of the effluent. Those compounds, such as metals, able to be quantified against national and international guidelines were well within acceptable levels. Others, such as resin acids, were found in lower quantities than in a previous study. A correlation between organics related to leachate from the logs, inorganic compounds found in the effluent and sediment grain size, indicates that some elements of the runoff may reach further into the harbour. The influence of dredging and disturbance of the seabed by shipping movements is considered in relation to this.
Levels of organic compounds, related to the log storage in transplanted mussel populations, were not detected spatially or temporally and no evidence of bio-accumulation of resin acids was found.
Based on the combined findings there are very low detectable effects on the marine environment from the runoff of the Port of Tauranga log storage areas. These come in the form of a gradient in chemical compounds related to the runoff and are well within the ANZECC (2000) Interim Guideline Levels. 
This study adds to the limited knowledge on log storage runoff into the marine environment and incorporates elements which can be applied to many areas of research related to stormwater discharge. It uses the Port of Tauranga runoff as a relevant example of issues and environmental responses related to urban and industrial stormwater runoff.

text: Characterisation, potential toxicity and fate of storm water run-off from log storage areas of the Port of Tauranga. Stormwater run-off from industrial sources can impact the receiving environment by the discharge of toxic substances, nutrients, sediments or fresh water (in marine environments). The Port of Tauranga is New Zealand’s largest by cargo volume with untreated logs being one of the major exports. The port stores logs totalling up to 300,000 m3 with an average residency time of 18 days. Runoff from log storage areas can cause toxicity to aquatic life due to low pH, high organic solids content and associated BOD, and chemicals leached from timber such as resin acids. Metals and PAH’s from heavy vehicles and other machinery can also be present. 
At the port, stormwater collects from the storage areas into slot drains and is screened for larger particulates in screening chambers before discharging into Tauranga Harbour. Large rainfall events produce a visible, highly coloured plume extending across the main harbour channel. 
This study looks at compounds within the stormwater runoff and associated marine water samples and the toxicology of the effluent. It then focusses on the gradients of compounds found in sediments and biota in relation to the main discharge sources. This is followed with a more specific investigation of the bioaccumulation of resin acids in resident and transplanted mussels. It concludes with a comparison of low intertidal species assemblages within and outside the influence of the stormwater plume.
Findings indicate that there are high levels of wood derived chemicals in the stormwater runoff and a gradient of quantities of these can be detected in nearby sediments, decreasing with distance from the discharge point of the effluent. Those compounds, such as metals, able to be quantified against national and international guidelines were well within acceptable levels. Others, such as resin acids, were found in lower quantities than in a previous study. A correlation between organics related to leachate from the logs, inorganic compounds found in the effluent and sediment grain size, indicates that some elements of the runoff may reach further into the harbour. The influence of dredging and disturbance of the seabed by shipping movements is considered in relation to this.
Levels of organic compounds, related to the log storage in transplanted mussel populations, were not detected spatially or temporally and no evidence of bio-accumulation of resin acids was found.
Based on the combined findings there are very low detectable effects on the marine environment from the runoff of the Port of Tauranga log storage areas. These come in the form of a gradient in chemical compounds related to the runoff and are well within the ANZECC (2000) Interim Guideline Levels. 
This study adds to the limited knowledge on log storage runoff into the marine environment and incorporates elements which can be applied to many areas of research related to stormwater discharge. It uses the Port of Tauranga runoff as a relevant example of issues and environmental responses related to urban and industrial stormwater runoff.

year: 2015

title: A pedagogical framework for embedding computational thinking in authentic technology practice

authors: Fox-Turnbull, Wendy

subjects: authentic technology practice

abstract: Computational thinking is an aspect of digital technologies in the New Zealand Curriculum that teaches children to approach problems systematically, using logical and analytical reasoning.  This paper presents a study undertaken in a small-town primary school in New Zealand with a high population of Māori students. The study drew on four aspects from Kotsopoulos et al.’s framework of pedagogical experiences: unplugged, tinkering, making, remixing to investigate pedagogical strategies that facilitate the successful embedding of computational thinking within authentic technological practice. The research aimed to identify learning pedagogies that support young learners in their understanding of computational thinking through designing and developing digital technologies. The qualitative methodologies were informed by the three pedagogical principles from Bishop and Berryman to guide the research design and frame learning support for students. Key themes that emerged from the data included the values of local context, self-autonomy, classroom organisation, use of physical and digital manipulatives. Finally, the paper presents a model for the pedagogical delivery of computational thinking when embedded in technological practice in primary schools, drawing from and adding to Kotsopoulos and colleague’s pedagogical framework. The most significant modification situates the existing model within authentic technology practice, providing context for learning. The model shows an adjustment from ‘Making’ to ‘Designing and Making’, thus strengthening the position of digital technologies within the Technology learning area.  The model also signals that authentic technological within a primary classroom practice is heavily impacted by ‘the pragmatics of delivery’ through a range of pedagogical and organisational strategies developed to ensure the needs of all students are met and to support them through their learning journey in computational thinking. The last significant modification of Kotsopoulos and colleagues’ model is the removal of ‘remixing’ because the primary aged students in this study did not reach the level of sophistication required for remixing. The aim of the framework is to assist teachers and teacher educators to design and develop successful teaching and learning strategies for implementing computational thinking into authentic technology practice in primary schools.

text: A pedagogical framework for embedding computational thinking in authentic technology practice Computational thinking is an aspect of digital technologies in the New Zealand Curriculum that teaches children to approach problems systematically, using logical and analytical reasoning.  This paper presents a study undertaken in a small-town primary school in New Zealand with a high population of Māori students. The study drew on four aspects from Kotsopoulos et al.’s framework of pedagogical experiences: unplugged, tinkering, making, remixing to investigate pedagogical strategies that facilitate the successful embedding of computational thinking within authentic technological practice. The research aimed to identify learning pedagogies that support young learners in their understanding of computational thinking through designing and developing digital technologies. The qualitative methodologies were informed by the three pedagogical principles from Bishop and Berryman to guide the research design and frame learning support for students. Key themes that emerged from the data included the values of local context, self-autonomy, classroom organisation, use of physical and digital manipulatives. Finally, the paper presents a model for the pedagogical delivery of computational thinking when embedded in technological practice in primary schools, drawing from and adding to Kotsopoulos and colleague’s pedagogical framework. The most significant modification situates the existing model within authentic technology practice, providing context for learning. The model shows an adjustment from ‘Making’ to ‘Designing and Making’, thus strengthening the position of digital technologies within the Technology learning area.  The model also signals that authentic technological within a primary classroom practice is heavily impacted by ‘the pragmatics of delivery’ through a range of pedagogical and organisational strategies developed to ensure the needs of all students are met and to support them through their learning journey in computational thinking. The last significant modification of Kotsopoulos and colleagues’ model is the removal of ‘remixing’ because the primary aged students in this study did not reach the level of sophistication required for remixing. The aim of the framework is to assist teachers and teacher educators to design and develop successful teaching and learning strategies for implementing computational thinking into authentic technology practice in primary schools.

year: 2025