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: Evaluation of a stratified tank based heat recovery loop via dynamic simulation

authors: Schlosser, Florian

abstract: Prerequisite for hot water recovery in the dairy and beverage industry is the use of heat storage, such as stratified tanks. Total Site Heat Integration enables the targeting of heat recovery potential, the concrete identification of suitable sinks and source profiles and the dimensioning of intermediate circuits and storages. For a cost and energy efficient storage, the aim to maintain stratification by suitable thermocline control management. Dynamic simulation enables a reliable estimation of energy savings and correct storage/control design considering the changing operation times, source and sink loads as well as thermal inertias. This poses two challenges: model accuracy and acceptable simulation time. A stratified tank model with Variable Layer Height (VLH) is evolved reducing numeric diffusion effects. A sensitive analysis shows the increased accuracy with acceptable simulation time. As part of a case study, thermocline growth due to numeric diffusion is reduced up to approximately 35 % by a VLH model. The model is simulated for a case study in the dairy industry. It is shown that up to 94 % of the total heat recovery target can be achieved by the modelled heat recovery loop based on a stratified tank and the applied system control.

text: Evaluation of a stratified tank based heat recovery loop via dynamic simulation Prerequisite for hot water recovery in the dairy and beverage industry is the use of heat storage, such as stratified tanks. Total Site Heat Integration enables the targeting of heat recovery potential, the concrete identification of suitable sinks and source profiles and the dimensioning of intermediate circuits and storages. For a cost and energy efficient storage, the aim to maintain stratification by suitable thermocline control management. Dynamic simulation enables a reliable estimation of energy savings and correct storage/control design considering the changing operation times, source and sink loads as well as thermal inertias. This poses two challenges: model accuracy and acceptable simulation time. A stratified tank model with Variable Layer Height (VLH) is evolved reducing numeric diffusion effects. A sensitive analysis shows the increased accuracy with acceptable simulation time. As part of a case study, thermocline growth due to numeric diffusion is reduced up to approximately 35 % by a VLH model. The model is simulated for a case study in the dairy industry. It is shown that up to 94 % of the total heat recovery target can be achieved by the modelled heat recovery loop based on a stratified tank and the applied system control.

year: 2018

title: Ngāti Whakaue Māngai Nui

authors: Hiini, Anaha Te Wheoro

subjects: Ngāti Whakaue Māngai Nui

abstract: Ko Ngāti Whakaue tētehi iwi ahurei o te waka o Te Arawa.  Ko tētehi taha ōna kei ngā tahataha o te kōroto moana o Te Rotorua-nui-a-Kahumatamomoe, i Waingaehe ki Waimihia.  Ko tētehi atu taha ōna kei te ūnga o te waka rongomaiwhiti o Te Arawa, arā ki Maketū.  
Kua whai mana a Ngāti Whakaue i ngā rautau e tū whakahīhī ai rātau hei iwi mana nui i ō rātau pūkenga me ō rātau pūmanawa kia mau tonu tō rātau Whakauetanga, tō rātau ahurea me ā rātau tikanga.   Ko tētehi pūkenga pēnei i te āheinga ki te whakairo i te kupu rōreka, ki te tuitui i te kōrero i whakaputaina ai te kōrero ‘Te Arawa Māngai Nui’.  He mea whakapuaki te kōrero rā e iwi kē ki te whakanui i ngā pūkōrero o ngā paepae o Te Arawa, ka mutu, koirā hoki tētehi pūkenga i hau ai te rongo o Ngāti Whakaue.  
Nā, ko te pūkenga e kōrerohia nei, ko te reo o Ngāti Whakaue.  Ko tōna oranga tonutanga te kaupapa matua o tēnei tuhinga e rangahaua ana i te putanga o te kōrero a tētehi o ngā koroua matatau o te iwi i te tau 1992, arā a Hamuera Mitchell, nāna tonu nei i whakapuaki ‘Ka mate te reo o Ngāti Whakaue ā te tekau tau’.  

Nō reira, he whakatewhatewhahanga tēnei tuhinga o te reo o Ngāti Whakaue o tua, o mohoa noa nei hoki kia mōhiotia ai te oranga, te matenga haeretanga rānei o te reo o te iwi, o ngā hapū, o te hapori, o te kāinga o nāianei, kia tau hoki mehemea āe rānei kua whai hua ngā rautaki reo o mua a Ngāti Whakaue ki te whakarauora i tōna ake reo, ā, ka aha te iwi e anga whakamua ai.  Ka mātaitia te āhua o te reo o Ngāti Whakaue kia mōhiotia mehemea i tika tā Hamera Mitchell i kī ai i te tau 1992, karekau rānei, mehemea rānei he wero kē nāna kia kaua e tukuna e te iwi o Ngāti Whakaue tō rātau reo kia mate.

Ko te tikanga rangahau Pākehā, ko te tikanga rangahau Māori, me ngā tikanga ako reo ka kaha mātaitia i tēnei tuhinga kia tika ai te kohinga o ngā raraunga o tēnei momo rangahau, ngā tikanga matatika a te wānanga, ngā tukanga tātari me te whakahōrapatanga atu i ngā whakataunga o te rangahau.  

Hei āpiti atu, ka kōrerohia ngā kaupapa mātauranga a Ngāti Whakaue, tae noa atu ki ngā tini kaupapa whakarauora reo a te iwi kua whakahaerehia mai i te tau 2005 ki ēnei rangi tonu nei mō te oranga o te reo o Ngāti Whakaue te take e anga tōtika atu ai ki te wetenga o te rautaki reo o mua a Ngāti Whakaue i whakahaerehia ai i ngā tau 2013 ki te tau 2017 i kitea ai ōna pikinga, ōna hekenga, ōna ngoikoretanga me ōna hua.  

Heoi anō, hei whaiwhai noa ake i te rautaki o mua nei, ko ngā mātātuhi kua mahue iho rā, ko te korenga o ngā arotakenga, ko te korenga o ngā pūrongo, ko te korenga o ētehi taunakitanga ā-tuhi nei, ko te korenga o tētehi aha kē atu rānei kia kitea he hua, he pikinga, he hekenga, he aha rānei.  Ahakoa tērā raru, nā te kitenga me te rongotanga o te pikinga haeretanga o te āhua o te reo, nā ngā kōrero ā-waha me ngā kauhau a ētehi mō ngā hua i puta ai i te rautaki reo o mua a Ngāti Whakaue i mana ai te whakahaumanutanga o te reo o ngā paepae o te iwi.

Nā te mea ko te reo Māori te remurere o te kaituhi nei, kua tekau mā waru tau ia e whai ana i te kaupapa i a ia e whakaako ana, i a ia e wānanga ana, i a ia hoki e whakapau kaha ana ki te whakaora anō i te reo Māori, kua whakaritea e ia tētehi rautaki reo hou e toru tekau tau te roa hei kōkiri mā te iwi e ora rawa atu anō ai te reo o Ngāti Whakaue, e whai hua anō ai hoki te whakapuakitanga o te kōrero rā ‘Te Arawa Māngai Nui’, hei tohu whakanui i ngā pūkenga kōrero o te iwi.

E ai ki te kōrero, ‘he tīmohea kua pakari’.  Nā roto i te āta rangahaua o te kaupapa nei i mōhio ai e ora tonu nei te reo o Ngāti Whakaue, heoi, kāore e pērā rawa te kaha o te oranga i te wā i a kui mā, i a koro mā.  Ahakoa te kōrero mō te matenga haeretanga o te reo o Ngāti Whakaue, nā ngā kaupapa whakaora reo a te iwi i ngā tau i piki anō ai te oranga o te reo, ka mutu, mā te whakahaerenga tonutanga o ngā wānanga nei e ora tonu anō ai te reo.

text: Ngāti Whakaue Māngai Nui Ko Ngāti Whakaue tētehi iwi ahurei o te waka o Te Arawa.  Ko tētehi taha ōna kei ngā tahataha o te kōroto moana o Te Rotorua-nui-a-Kahumatamomoe, i Waingaehe ki Waimihia.  Ko tētehi atu taha ōna kei te ūnga o te waka rongomaiwhiti o Te Arawa, arā ki Maketū.  
Kua whai mana a Ngāti Whakaue i ngā rautau e tū whakahīhī ai rātau hei iwi mana nui i ō rātau pūkenga me ō rātau pūmanawa kia mau tonu tō rātau Whakauetanga, tō rātau ahurea me ā rātau tikanga.   Ko tētehi pūkenga pēnei i te āheinga ki te whakairo i te kupu rōreka, ki te tuitui i te kōrero i whakaputaina ai te kōrero ‘Te Arawa Māngai Nui’.  He mea whakapuaki te kōrero rā e iwi kē ki te whakanui i ngā pūkōrero o ngā paepae o Te Arawa, ka mutu, koirā hoki tētehi pūkenga i hau ai te rongo o Ngāti Whakaue.  
Nā, ko te pūkenga e kōrerohia nei, ko te reo o Ngāti Whakaue.  Ko tōna oranga tonutanga te kaupapa matua o tēnei tuhinga e rangahaua ana i te putanga o te kōrero a tētehi o ngā koroua matatau o te iwi i te tau 1992, arā a Hamuera Mitchell, nāna tonu nei i whakapuaki ‘Ka mate te reo o Ngāti Whakaue ā te tekau tau’.  

Nō reira, he whakatewhatewhahanga tēnei tuhinga o te reo o Ngāti Whakaue o tua, o mohoa noa nei hoki kia mōhiotia ai te oranga, te matenga haeretanga rānei o te reo o te iwi, o ngā hapū, o te hapori, o te kāinga o nāianei, kia tau hoki mehemea āe rānei kua whai hua ngā rautaki reo o mua a Ngāti Whakaue ki te whakarauora i tōna ake reo, ā, ka aha te iwi e anga whakamua ai.  Ka mātaitia te āhua o te reo o Ngāti Whakaue kia mōhiotia mehemea i tika tā Hamera Mitchell i kī ai i te tau 1992, karekau rānei, mehemea rānei he wero kē nāna kia kaua e tukuna e te iwi o Ngāti Whakaue tō rātau reo kia mate.

Ko te tikanga rangahau Pākehā, ko te tikanga rangahau Māori, me ngā tikanga ako reo ka kaha mātaitia i tēnei tuhinga kia tika ai te kohinga o ngā raraunga o tēnei momo rangahau, ngā tikanga matatika a te wānanga, ngā tukanga tātari me te whakahōrapatanga atu i ngā whakataunga o te rangahau.  

Hei āpiti atu, ka kōrerohia ngā kaupapa mātauranga a Ngāti Whakaue, tae noa atu ki ngā tini kaupapa whakarauora reo a te iwi kua whakahaerehia mai i te tau 2005 ki ēnei rangi tonu nei mō te oranga o te reo o Ngāti Whakaue te take e anga tōtika atu ai ki te wetenga o te rautaki reo o mua a Ngāti Whakaue i whakahaerehia ai i ngā tau 2013 ki te tau 2017 i kitea ai ōna pikinga, ōna hekenga, ōna ngoikoretanga me ōna hua.  

Heoi anō, hei whaiwhai noa ake i te rautaki o mua nei, ko ngā mātātuhi kua mahue iho rā, ko te korenga o ngā arotakenga, ko te korenga o ngā pūrongo, ko te korenga o ētehi taunakitanga ā-tuhi nei, ko te korenga o tētehi aha kē atu rānei kia kitea he hua, he pikinga, he hekenga, he aha rānei.  Ahakoa tērā raru, nā te kitenga me te rongotanga o te pikinga haeretanga o te āhua o te reo, nā ngā kōrero ā-waha me ngā kauhau a ētehi mō ngā hua i puta ai i te rautaki reo o mua a Ngāti Whakaue i mana ai te whakahaumanutanga o te reo o ngā paepae o te iwi.

Nā te mea ko te reo Māori te remurere o te kaituhi nei, kua tekau mā waru tau ia e whai ana i te kaupapa i a ia e whakaako ana, i a ia e wānanga ana, i a ia hoki e whakapau kaha ana ki te whakaora anō i te reo Māori, kua whakaritea e ia tētehi rautaki reo hou e toru tekau tau te roa hei kōkiri mā te iwi e ora rawa atu anō ai te reo o Ngāti Whakaue, e whai hua anō ai hoki te whakapuakitanga o te kōrero rā ‘Te Arawa Māngai Nui’, hei tohu whakanui i ngā pūkenga kōrero o te iwi.

E ai ki te kōrero, ‘he tīmohea kua pakari’.  Nā roto i te āta rangahaua o te kaupapa nei i mōhio ai e ora tonu nei te reo o Ngāti Whakaue, heoi, kāore e pērā rawa te kaha o te oranga i te wā i a kui mā, i a koro mā.  Ahakoa te kōrero mō te matenga haeretanga o te reo o Ngāti Whakaue, nā ngā kaupapa whakaora reo a te iwi i ngā tau i piki anō ai te oranga o te reo, ka mutu, mā te whakahaerenga tonutanga o ngā wānanga nei e ora tonu anō ai te reo.

year: 2020