title: Novel approaches for modelling changes in phytoplankton diversity and lake ecosystem function

authors: Muraoka, Kohji

abstract: Ecosystem function represents the collective outcome of many different processes. Function may be interrupted by events that originate from outside a system, influencing biological diversity dynamics. Difficulties in expressing how a system is functioning originate firstly from being able to define a normative status for a dynamic system and secondly from the accuracy of common metrics of biodiversity changes. In this thesis, I used a numerical model and high-frequency ecological observations to express functioning of a system. Chapter 2 used biogeochemical parameter perturbations in a lake ecological model to identify seasonal parameter sensitivity variabilities. A set of internal process parameters of calibrated shallow eutrophic Lake Waahi DYRESM-CAEDYM ecological model was used to apply Monte-Carlo perturbation. Analysis was conducted by examining the collective results variability, a “spread” of the ensemble results from the iteration. The results showed that the spreads were small when lake inflows had high discharge, suggesting that lake internal dynamics had lesser effect on water quality and inflows dominated the system dynamics. Due to the simplicity of the methods, regular use of perturbation methods is suggested to assess model uncertainty and to better understand the model. Chapter 3 used interdisciplinary methods to identify changes in dissolved oxygen (DO) observations caused by biological processes. DO in lakes is a key indicator of ecosystem function. Methods used in this chapter included expert panel decision making, Symbolic Aggregate approXimation (SAX) analysis, and text classification. The use of an expert panel was motivated by the common practice of DO data visual assessment. Variability in experts’ boundaries for data quality were observed by data survey, reinforcing the necessity of robust and reproducible methods for unbiased analysis. Surface DO sensor data from 18 global lakes were used to create day-long data segments. The modelling framework successfully simulated the expert panel decisions on these segments, automatically labelling data to indicate when the signal is likely dominated by biological activities. In Chapter 4, species-neutral biological assemblage metrics were developed to account for phytoplankton changes associated with changes in species abundance. Every species’ population changes were converted into binary metrics (i.e., increases or decreases) to identify the “constituents” of species richness, to allow robust assessments of population dynamics. Four lakes (Lakes Annie, Feeagh, Esthwaite and Mendota) from different regions were analysed. The results showed several previously undocumented features. Species recruitment was proportional to the number of species that were increasing. The number of species that were decreasing did not immediately increase the number of species that went extinct. The rate of increase was logarithmically distributed from the fastest to the slowest growing species, with the distribution shape being strongly influenced by number of species that were increasing. Such species-neutral community metrics, along with abundance distribution and diversity, are helpful to assess mechanistic community ecology models. This thesis provides toolsets useful for future studies to understand relationships between forcing and functioning of ecosystems and changes in biodiversity, by providing means to assess ecosystem function and demonstrating examples of species-neutral community structural changes.

text: Novel approaches for modelling changes in phytoplankton diversity and lake ecosystem function Ecosystem function represents the collective outcome of many different processes. Function may be interrupted by events that originate from outside a system, influencing biological diversity dynamics. Difficulties in expressing how a system is functioning originate firstly from being able to define a normative status for a dynamic system and secondly from the accuracy of common metrics of biodiversity changes. In this thesis, I used a numerical model and high-frequency ecological observations to express functioning of a system. Chapter 2 used biogeochemical parameter perturbations in a lake ecological model to identify seasonal parameter sensitivity variabilities. A set of internal process parameters of calibrated shallow eutrophic Lake Waahi DYRESM-CAEDYM ecological model was used to apply Monte-Carlo perturbation. Analysis was conducted by examining the collective results variability, a “spread” of the ensemble results from the iteration. The results showed that the spreads were small when lake inflows had high discharge, suggesting that lake internal dynamics had lesser effect on water quality and inflows dominated the system dynamics. Due to the simplicity of the methods, regular use of perturbation methods is suggested to assess model uncertainty and to better understand the model. Chapter 3 used interdisciplinary methods to identify changes in dissolved oxygen (DO) observations caused by biological processes. DO in lakes is a key indicator of ecosystem function. Methods used in this chapter included expert panel decision making, Symbolic Aggregate approXimation (SAX) analysis, and text classification. The use of an expert panel was motivated by the common practice of DO data visual assessment. Variability in experts’ boundaries for data quality were observed by data survey, reinforcing the necessity of robust and reproducible methods for unbiased analysis. Surface DO sensor data from 18 global lakes were used to create day-long data segments. The modelling framework successfully simulated the expert panel decisions on these segments, automatically labelling data to indicate when the signal is likely dominated by biological activities. In Chapter 4, species-neutral biological assemblage metrics were developed to account for phytoplankton changes associated with changes in species abundance. Every species’ population changes were converted into binary metrics (i.e., increases or decreases) to identify the “constituents” of species richness, to allow robust assessments of population dynamics. Four lakes (Lakes Annie, Feeagh, Esthwaite and Mendota) from different regions were analysed. The results showed several previously undocumented features. Species recruitment was proportional to the number of species that were increasing. The number of species that were decreasing did not immediately increase the number of species that went extinct. The rate of increase was logarithmically distributed from the fastest to the slowest growing species, with the distribution shape being strongly influenced by number of species that were increasing. Such species-neutral community metrics, along with abundance distribution and diversity, are helpful to assess mechanistic community ecology models. This thesis provides toolsets useful for future studies to understand relationships between forcing and functioning of ecosystems and changes in biodiversity, by providing means to assess ecosystem function and demonstrating examples of species-neutral community structural changes.

year: 2019

title: New Zealand Youth Rugby Sevens: A Comparative Match Demands Study

authors: Wintershoven, Koen

subjects: U15/U19

abstract: Rugby sevens has established itself on the world stage since its inclusion in the 2016 Olympics. Participation among New Zealand (NZ) youth has surged. Sevens games have specific high demands, but little is known about these competitive demands in regards to youth. Two NZ male youth squads (U15, n = 13; U19, n = 14) were monitored during a national sevens tournament. Microsensor technology captured heart rate (HR) and kinematic performance. The rating of perceived exertion (RPE) was collected for U15 matches only. U19 and U15 players ran 108 ± 11 and 116 ± 13 m·min-1 at an average speed (VAVG) of 6.5 ± 0.6 and 6.9 ± 0.8 km·h-1. Peak speeds (VPEAK) reached 33.7 km·h-1, and high-intensity running distance (HIRD) averaged 252 ± 102 m. U15 (44.3 ± 9.2 game-1) and U19 (39.4 ± 6.1 game-1) showed different sprint rates. U15 covered more moderate-velocity distance (20-80% VMAX) and less low-velocity distance (<20% VMAX). RPE was 13 ± 1 (U15). An average HR of 90.0 ± 3.9% HRMAX was recorded. Upwards of 57% of game time was played at >95% HRMAX. Youth sevens competition is specifically demanding. U15 can experience greater loads than older peers in rugby. Coaches can use this information to optimize players' physical development.

text: New Zealand Youth Rugby Sevens: A Comparative Match Demands Study Rugby sevens has established itself on the world stage since its inclusion in the 2016 Olympics. Participation among New Zealand (NZ) youth has surged. Sevens games have specific high demands, but little is known about these competitive demands in regards to youth. Two NZ male youth squads (U15, n = 13; U19, n = 14) were monitored during a national sevens tournament. Microsensor technology captured heart rate (HR) and kinematic performance. The rating of perceived exertion (RPE) was collected for U15 matches only. U19 and U15 players ran 108 ± 11 and 116 ± 13 m·min-1 at an average speed (VAVG) of 6.5 ± 0.6 and 6.9 ± 0.8 km·h-1. Peak speeds (VPEAK) reached 33.7 km·h-1, and high-intensity running distance (HIRD) averaged 252 ± 102 m. U15 (44.3 ± 9.2 game-1) and U19 (39.4 ± 6.1 game-1) showed different sprint rates. U15 covered more moderate-velocity distance (20-80% VMAX) and less low-velocity distance (<20% VMAX). RPE was 13 ± 1 (U15). An average HR of 90.0 ± 3.9% HRMAX was recorded. Upwards of 57% of game time was played at >95% HRMAX. Youth sevens competition is specifically demanding. U15 can experience greater loads than older peers in rugby. Coaches can use this information to optimize players' physical development.

year: 2023-03-31

title: Kōauau auē, e auau tō au e! The Kōauau in Te Ao Māori.

authors: Komene, Jo'el

subjects: Kōauau

abstract: In recent years there has been a revival of interest in traditional Māori musical instruments, including the kōauau. This thesis studies kōauau informed by a Māori framework, giving weight to traditional Māori knowledge and practices, emphasizing the spiritual dimensions of the instrument in its origins and its functions. The thesis defines the kōauau and how it is distinct from other taonga pūoro in its physical characteristics. It then presents the traditions associated with the kōauau which link its origins to the atua and their natural world, especially Raukatauri, together with other traditions from many rohe throughout Aotearoa.  The thesis describes the traditional tools and methods of construction, the role of atua in the construction process, materials used for kōauau, how they were embellished, and their use as adornments. The techniques for playing kōauau are analyzed, and there is a discussion of the occasions on which kōauau were played, and the purposes of performing on kōauau. The thesis also presents the texts of several traditional waiata kōauau. A number of traditional kōauau in storage at the Auckland Museum were able to be examined to confirm and extend documentary evidence about materials, construction methods, and embellishment. The discussion also comments on the quot;voicesquot; for those kōauau in the museum collection that could be sounded. The decline in kōauau performance during the twentieth century is outlined, and there is a summary of successful efforts in the later twentieth century to revive taonga pūoro, including kōauau. The thesis brings together in concise form much scattered information so that current and future performers with kōauau are able to give full consideration to its place in te ao Māori.

text: Kōauau auē, e auau tō au e! The Kōauau in Te Ao Māori. In recent years there has been a revival of interest in traditional Māori musical instruments, including the kōauau. This thesis studies kōauau informed by a Māori framework, giving weight to traditional Māori knowledge and practices, emphasizing the spiritual dimensions of the instrument in its origins and its functions. The thesis defines the kōauau and how it is distinct from other taonga pūoro in its physical characteristics. It then presents the traditions associated with the kōauau which link its origins to the atua and their natural world, especially Raukatauri, together with other traditions from many rohe throughout Aotearoa.  The thesis describes the traditional tools and methods of construction, the role of atua in the construction process, materials used for kōauau, how they were embellished, and their use as adornments. The techniques for playing kōauau are analyzed, and there is a discussion of the occasions on which kōauau were played, and the purposes of performing on kōauau. The thesis also presents the texts of several traditional waiata kōauau. A number of traditional kōauau in storage at the Auckland Museum were able to be examined to confirm and extend documentary evidence about materials, construction methods, and embellishment. The discussion also comments on the quot;voicesquot; for those kōauau in the museum collection that could be sounded. The decline in kōauau performance during the twentieth century is outlined, and there is a summary of successful efforts in the later twentieth century to revive taonga pūoro, including kōauau. The thesis brings together in concise form much scattered information so that current and future performers with kōauau are able to give full consideration to its place in te ao Māori.

year: 2009