title: Development of a non-lethal biopsy technique for estimating total tetrodotoxin concentrations in the grey side-gilled sea slug Pleurobranchaea maculata

authors: Khor, Serena

subjects: Biopsy

abstract: High concentrations of tetrodotoxin (TTX) have been detected in some New Zealand populations of Pleurobranchaea maculata (grey side-gilled sea slug). Within toxic populations there is significant variability in TTX concentrations among individuals, with up to 60-fold differences measured. This variability has led to challenges when conducting controlled laboratory experiments. The current method for assessing TTX concentrations within P. maculata is lethal, thus multiple individuals must be harvested at each sampling point to produce statistically meaningful data. In this study a method was developed for taking approximately 200 mg tissue biopsies using a TemnoEvolution® 18G × 11 cm Biopsy Needle inserted transversely into the foot. Correlation between the TTX concentrations in the biopsy sample and total TTX levels and in individual tissues were assessed. Six P. maculata were biopsied twice (nine days apart) and each individual was frozen immediately following the second sampling. Tetrodotoxin concentrations in biopsy samples and in the gonad, stomach, mantle and the remaining combined tissues and fluids were measured using liquid chromatography-mass spectrometry. Based on the proportional weight of the organs/tissues a total TTX concentration for each individual was calculated. There were strong correlations between biopsy TTX concentrations and the total (r2 = 0.88), stomach (r2 = 0.92) and gonad (r2 = 0.83) TTX concentrations. This technique will enable more robust laboratory studies to be undertaken, thereby assisting in understanding TTX kinetics, ecological function and origin within P. maculata.

text: Development of a non-lethal biopsy technique for estimating total tetrodotoxin concentrations in the grey side-gilled sea slug Pleurobranchaea maculata High concentrations of tetrodotoxin (TTX) have been detected in some New Zealand populations of Pleurobranchaea maculata (grey side-gilled sea slug). Within toxic populations there is significant variability in TTX concentrations among individuals, with up to 60-fold differences measured. This variability has led to challenges when conducting controlled laboratory experiments. The current method for assessing TTX concentrations within P. maculata is lethal, thus multiple individuals must be harvested at each sampling point to produce statistically meaningful data. In this study a method was developed for taking approximately 200 mg tissue biopsies using a TemnoEvolution® 18G × 11 cm Biopsy Needle inserted transversely into the foot. Correlation between the TTX concentrations in the biopsy sample and total TTX levels and in individual tissues were assessed. Six P. maculata were biopsied twice (nine days apart) and each individual was frozen immediately following the second sampling. Tetrodotoxin concentrations in biopsy samples and in the gonad, stomach, mantle and the remaining combined tissues and fluids were measured using liquid chromatography-mass spectrometry. Based on the proportional weight of the organs/tissues a total TTX concentration for each individual was calculated. There were strong correlations between biopsy TTX concentrations and the total (r2 = 0.88), stomach (r2 = 0.92) and gonad (r2 = 0.83) TTX concentrations. This technique will enable more robust laboratory studies to be undertaken, thereby assisting in understanding TTX kinetics, ecological function and origin within P. maculata.

year: 2013

title: Evaluating 50 years of time-series soil radiocarbon data: Towards routine calculation of robust C residence times

authors: Baisden, W. Troy

subjects: ¹⁴C

abstract: In 1959, Athol Rafter began a substantial programme of monitoring the flow of ¹⁴C produced by atmospheric thermonuclear tests through New Zealand's atmosphere, biosphere and soil. By building on the original measurements through ongoing sampling, a database of over 500 soil radiocarbon measurements spanning 50 years has now been compiled. The datasets, including an 11-point time series, allow strong focus on the robust quantification of residence times ranging from years to decades. We describe key aspects of the dataset, including the ability to identify critical assumptions inherent in calculating soil C residence times. The 3 most critical assumptions relate to: (1) the proportion of old C ("fraction passive"), (2) the lag time between photosynthesis and C entering the modeled pool, and (3) changes in the rates of C input (i. e., steady state). We demonstrate the ability to compare residence times in contrasting sites, such Andisols and non-Andisols, and the ability to calculate residence times across a range of soil depths. We use ¹⁴C in a two-box model to quantify soil carbon turnover parameters in deforested dairy pastures under similar climate in the Tokomaru silt loam (non-Andisol) versus the Egmont black loam (Andisol), originally sampled in 1962, 1965 and 1969, and resampled again in 2008. The ¹⁴C-based residence times of the main soil C pool in surface soil (~8 cm) are ~9 years in the Tokomaru soils compared to ~17 years for the Egmont soils. This difference represents nearly a doubling of soil C residence time, and roughly explains the doubling of the soil C stock. Passive soil C comprises 15% of the soil C pool in Tokomaru soils versus 27% in Egmont soils. A similar difference in residence times is found in a second surface soil comparison between the Bruntwood soil (Andisol) and the Te Kowhai soil (non-Andisol) with residence times of 18 and 27 years, respectively. The comparisons support evidence that C dynamics do differ in Andisols versus non-Andisols, as a result of both the mineral allophane and Al complexation. Expanding our calculations beyond surface soil, we show that thickening the calculation depth by combining horizons allows robust residence times to be calculated at a range of depths. Overall, the large and systematically collected dataset demonstrate that soil C residence times of the main soil C pool can be routinely calculated using ¹⁴C wherever samples collected 10 or more years apart in New Zealand grassland soils are available, and presumably under similar circumstances in other soils worldwide.

text: Evaluating 50 years of time-series soil radiocarbon data: Towards routine calculation of robust C residence times In 1959, Athol Rafter began a substantial programme of monitoring the flow of ¹⁴C produced by atmospheric thermonuclear tests through New Zealand's atmosphere, biosphere and soil. By building on the original measurements through ongoing sampling, a database of over 500 soil radiocarbon measurements spanning 50 years has now been compiled. The datasets, including an 11-point time series, allow strong focus on the robust quantification of residence times ranging from years to decades. We describe key aspects of the dataset, including the ability to identify critical assumptions inherent in calculating soil C residence times. The 3 most critical assumptions relate to: (1) the proportion of old C ("fraction passive"), (2) the lag time between photosynthesis and C entering the modeled pool, and (3) changes in the rates of C input (i. e., steady state). We demonstrate the ability to compare residence times in contrasting sites, such Andisols and non-Andisols, and the ability to calculate residence times across a range of soil depths. We use ¹⁴C in a two-box model to quantify soil carbon turnover parameters in deforested dairy pastures under similar climate in the Tokomaru silt loam (non-Andisol) versus the Egmont black loam (Andisol), originally sampled in 1962, 1965 and 1969, and resampled again in 2008. The ¹⁴C-based residence times of the main soil C pool in surface soil (~8 cm) are ~9 years in the Tokomaru soils compared to ~17 years for the Egmont soils. This difference represents nearly a doubling of soil C residence time, and roughly explains the doubling of the soil C stock. Passive soil C comprises 15% of the soil C pool in Tokomaru soils versus 27% in Egmont soils. A similar difference in residence times is found in a second surface soil comparison between the Bruntwood soil (Andisol) and the Te Kowhai soil (non-Andisol) with residence times of 18 and 27 years, respectively. The comparisons support evidence that C dynamics do differ in Andisols versus non-Andisols, as a result of both the mineral allophane and Al complexation. Expanding our calculations beyond surface soil, we show that thickening the calculation depth by combining horizons allows robust residence times to be calculated at a range of depths. Overall, the large and systematically collected dataset demonstrate that soil C residence times of the main soil C pool can be routinely calculated using ¹⁴C wherever samples collected 10 or more years apart in New Zealand grassland soils are available, and presumably under similar circumstances in other soils worldwide.

year: 2013

title: A trans-national analysis of equitable utilisation and minimisation of environmental harm under environmental laws at international, federal and national levels

authors: Hasan, Qaraman

subjects: International Environmental Law

abstract: Due to increasing demand for various human needs and climate change issues, rivers are now under enormous pressure. With increasing pressure on these valuable natural resources, responses among state and non-state actors are insufficient in the Anthropocene. To fill the gap, International Environmental Law (IEL) provides several principles for better management of these resources. Equitable utilisation and minimisation of environmental harm are among the most important principles of the IEL. From a theoretical perspective, these principles should lead to the sustainability of these resources and promote cooperation among relevant actors.

However, many river basins are still not allocated equitably and suffer from environmental damage. By using comparative, doctrinal, and empirical research methods, this thesis evaluates the two principles at the international level in Tigris and Euphrates River Basin, the federal level in Murray Darling Basin and at the local level in the Waikato River catchment. The research discovered major challenges for implementing the two principles. One major challenge is sovereignty, another is a lack or weakness of local voices and transparency. As the nature and status of all basins are different, the challenges are not exactly the same. For example, hearing local voices and better information transparency have significantly improved in the Waikato River.

As the challenges for implementing the two principles are not purely legal, the responses should blend legal solutions with political and socio-economic solutions. Therefore, this thesis strongly supports shared sovereignty among states at the international level as well as shared sovereignty with indigenous and minority groups at the national level. Cooperation among national and international actors in the river basins is also crucial for implementing the two principles effectively. Finally, there is the opportunity to establish basin institutions or organisations to manage river basins integrated and sustainable. This is vital in the case of TE-RB because the basin still lacks an institution. Furthermore, the basin institution in the MDB requires more robust compliance and monitoring power because the provisions of the Water Act 2007 and the basin plan still have not been implemented effectively.

Finally, the thesis concludes with two common lessons in comparing these cases. The first lesson is that equitable utilisation cannot be implemented effectively if it is not accepted by the local community in a broad and deep meaning. It means that the equitable allocation should be extended from only the riparian states to equitable allocation among the people within each state. The second lesson is that the minimisation of environmental harm cannot be implemented without determining the minimum flow of rivers, particularly transboundary rivers. Determining an environmental impact assessment for water projects and taking advantage of available solutions of nature contributes significantly in implementing the two principles and sustainable management of our rivers.

text: A trans-national analysis of equitable utilisation and minimisation of environmental harm under environmental laws at international, federal and national levels Due to increasing demand for various human needs and climate change issues, rivers are now under enormous pressure. With increasing pressure on these valuable natural resources, responses among state and non-state actors are insufficient in the Anthropocene. To fill the gap, International Environmental Law (IEL) provides several principles for better management of these resources. Equitable utilisation and minimisation of environmental harm are among the most important principles of the IEL. From a theoretical perspective, these principles should lead to the sustainability of these resources and promote cooperation among relevant actors.

However, many river basins are still not allocated equitably and suffer from environmental damage. By using comparative, doctrinal, and empirical research methods, this thesis evaluates the two principles at the international level in Tigris and Euphrates River Basin, the federal level in Murray Darling Basin and at the local level in the Waikato River catchment. The research discovered major challenges for implementing the two principles. One major challenge is sovereignty, another is a lack or weakness of local voices and transparency. As the nature and status of all basins are different, the challenges are not exactly the same. For example, hearing local voices and better information transparency have significantly improved in the Waikato River.

As the challenges for implementing the two principles are not purely legal, the responses should blend legal solutions with political and socio-economic solutions. Therefore, this thesis strongly supports shared sovereignty among states at the international level as well as shared sovereignty with indigenous and minority groups at the national level. Cooperation among national and international actors in the river basins is also crucial for implementing the two principles effectively. Finally, there is the opportunity to establish basin institutions or organisations to manage river basins integrated and sustainable. This is vital in the case of TE-RB because the basin still lacks an institution. Furthermore, the basin institution in the MDB requires more robust compliance and monitoring power because the provisions of the Water Act 2007 and the basin plan still have not been implemented effectively.

Finally, the thesis concludes with two common lessons in comparing these cases. The first lesson is that equitable utilisation cannot be implemented effectively if it is not accepted by the local community in a broad and deep meaning. It means that the equitable allocation should be extended from only the riparian states to equitable allocation among the people within each state. The second lesson is that the minimisation of environmental harm cannot be implemented without determining the minimum flow of rivers, particularly transboundary rivers. Determining an environmental impact assessment for water projects and taking advantage of available solutions of nature contributes significantly in implementing the two principles and sustainable management of our rivers.

year: 2023