title: Latitudinal variation in nutrient stoichiometry and chlorophyll-nutrient relationships in lakes: A global study

authors: Abell, Jonathan Michael

subjects: Eutrophication

abstract: We present analysis of variations in relationships between nitrogen (N), phosphorus (P) and chlorophyll-a (chl-a) in lakes along a gradient of latitude inclusive of tropical, temperate and polar regions. Total nitrogen (TN), total phosphorus (TP), chl-a, latitude and depth data were collated for 1316 lakes situated between 70 degrees S and 83 N. Latitudinal variation was then analysed for three empirical measures of phytoplankton nutrient limitation and/or nutrient assimilation. Lastly, chl-a near-maxima conditional on TN and TP abundance were empirically defined for this global dataset using quantile regression. Mean TN:TP increases with distance from the equator. This relationship is independent of variation in either lake depth or trophic state, reflecting latitudinal variation in nutrient cycling processes and/or nutrient sources. There is a negative linear relationship between latitude and chl-a:TN which similarly suggests that N is less abundant relative to phytoplankton growth requirements at lower latitudes. Relative to temperate lakes, the statistical capability of TN and TP to predict chl-a is poor for both tropical and polar lakes, reflecting latitudinal variation in lake ecosystem functioning and the subsequent potential unsuitability of applying relationships derived for temperate lakes elsewhere. Chl-a near-maxima correspond to chl-a:TN and chl-a:TP yields of 0.046:1 and 0.87:1 respectively, although some observations greatly exceed near-maxima, suggesting possible physiologically plastic phytoplankton responses in these exceptional cases. Deficiencies in understanding the mechanisms that drive variation in macro-nutrient stoichiometry and phytoplankton biomass-nutrient relationships across large spatial scales necessitates further landscape-scale research on this topic, particularly in the tropics.

text: Latitudinal variation in nutrient stoichiometry and chlorophyll-nutrient relationships in lakes: A global study We present analysis of variations in relationships between nitrogen (N), phosphorus (P) and chlorophyll-a (chl-a) in lakes along a gradient of latitude inclusive of tropical, temperate and polar regions. Total nitrogen (TN), total phosphorus (TP), chl-a, latitude and depth data were collated for 1316 lakes situated between 70 degrees S and 83 N. Latitudinal variation was then analysed for three empirical measures of phytoplankton nutrient limitation and/or nutrient assimilation. Lastly, chl-a near-maxima conditional on TN and TP abundance were empirically defined for this global dataset using quantile regression. Mean TN:TP increases with distance from the equator. This relationship is independent of variation in either lake depth or trophic state, reflecting latitudinal variation in nutrient cycling processes and/or nutrient sources. There is a negative linear relationship between latitude and chl-a:TN which similarly suggests that N is less abundant relative to phytoplankton growth requirements at lower latitudes. Relative to temperate lakes, the statistical capability of TN and TP to predict chl-a is poor for both tropical and polar lakes, reflecting latitudinal variation in lake ecosystem functioning and the subsequent potential unsuitability of applying relationships derived for temperate lakes elsewhere. Chl-a near-maxima correspond to chl-a:TN and chl-a:TP yields of 0.046:1 and 0.87:1 respectively, although some observations greatly exceed near-maxima, suggesting possible physiologically plastic phytoplankton responses in these exceptional cases. Deficiencies in understanding the mechanisms that drive variation in macro-nutrient stoichiometry and phytoplankton biomass-nutrient relationships across large spatial scales necessitates further landscape-scale research on this topic, particularly in the tropics.

year: 2012

title: Isolation, Characterization and Synthesis of a Phenyl-substituted Pyrrole Isolated from the Flavonoid Fraction of Mānuka Honey

authors: Chan, Ching Wan

subjects: Mānuka Honey

abstract: Compound 1, which occurs in the flavonoid fraction of mānuka honey and showed a statistical correlation with the non-peroxide antibacterial activity of the honeys, was extracted from fifteen kilograms of mānuka honey using Amberlite XAD-2 resin and liquid-liquid extraction, and isolated by a combination of Sephadex-LH20 column chromatography and HPLC. Characterization of 1 was achieved by one and 2D- 1H and 13C NMR spectroscopy and GC-MS and 1 was identified as 2-formyl-5-(2-methoxyphenyl)-pyrrole. In addition to 1, two other non-flavonoids were isolated from the flavonoid fraction and their identities confirmed as caffeic acid and p-coumaric acid. Synthesis of 9 (3-hydroxy-1-(2-methoxyphenyl)-3-(oxazol-4-yl) propan-1-one), an intermediate in the route to 1, gave a yield of 67.5% as a pale yellow crystals after crystallization from CH2Cl2/hexane. Synthesis of 1 from 9 only resulted in barely traceable amount of 1. The dominant product after recrystallization from CH2Cl2/hexane was 10 ((E)-1-(2-methoxyphenyl)-3-(oxazol-4-yl)prop-2-en-1-one) which was the dehydrated analogue of 9. The synthesis of 1 was repeated. The product mixture was fractionated on a silica gel column, followed by two cycles of preparative layer chromatography applied to the fractions which contained 1 and yield 0.36 mg of 1 (0.00179 mmol, 0.2%).

text: Isolation, Characterization and Synthesis of a Phenyl-substituted Pyrrole Isolated from the Flavonoid Fraction of Mānuka Honey Compound 1, which occurs in the flavonoid fraction of mānuka honey and showed a statistical correlation with the non-peroxide antibacterial activity of the honeys, was extracted from fifteen kilograms of mānuka honey using Amberlite XAD-2 resin and liquid-liquid extraction, and isolated by a combination of Sephadex-LH20 column chromatography and HPLC. Characterization of 1 was achieved by one and 2D- 1H and 13C NMR spectroscopy and GC-MS and 1 was identified as 2-formyl-5-(2-methoxyphenyl)-pyrrole. In addition to 1, two other non-flavonoids were isolated from the flavonoid fraction and their identities confirmed as caffeic acid and p-coumaric acid. Synthesis of 9 (3-hydroxy-1-(2-methoxyphenyl)-3-(oxazol-4-yl) propan-1-one), an intermediate in the route to 1, gave a yield of 67.5% as a pale yellow crystals after crystallization from CH2Cl2/hexane. Synthesis of 1 from 9 only resulted in barely traceable amount of 1. The dominant product after recrystallization from CH2Cl2/hexane was 10 ((E)-1-(2-methoxyphenyl)-3-(oxazol-4-yl)prop-2-en-1-one) which was the dehydrated analogue of 9. The synthesis of 1 was repeated. The product mixture was fractionated on a silica gel column, followed by two cycles of preparative layer chromatography applied to the fractions which contained 1 and yield 0.36 mg of 1 (0.00179 mmol, 0.2%).

year: 2011

title: Applying Kaupapa Māori Processes to Documentary Film.

authors: Waititi, Kahurangi Rora

subjects: Maori documentary

abstract: This thesis explores the application of Kaupapa Māori processes to documentary filmmaking through practiced-led research. The need for this research came to light through the experience of witnessing unacceptable behaviour shown by film crews towards kaumātua who were attending the 2006 28th Māori Battalion Reunion. In reflecting on this experience and considering my own filming experience as a person with a Te Ao Māori background, the basis for this argument was conceived. This thesis argues that there are alternative ways in which filming can be conducted by considering processes that already exist within Māori practices and philosophies.          

This Thesis, therefore, investigates alternative processes of filming that have developed from a Kaupapa Māori perspective through practical filming experience.  An historical overview of the relationship between Māori, media and filming practices have been provided to give context to this discussion.  The application of Kaupapa Māori processes to film was considered through the use of Marae protocol and philosophies. The application of these concepts was supported by the creative research which was utilised by referencing specific examples. The reader is, therefore, instructed to refer to the DVD in the front of the thesis as referenced in the written text.

text: Applying Kaupapa Māori Processes to Documentary Film. This thesis explores the application of Kaupapa Māori processes to documentary filmmaking through practiced-led research. The need for this research came to light through the experience of witnessing unacceptable behaviour shown by film crews towards kaumātua who were attending the 2006 28th Māori Battalion Reunion. In reflecting on this experience and considering my own filming experience as a person with a Te Ao Māori background, the basis for this argument was conceived. This thesis argues that there are alternative ways in which filming can be conducted by considering processes that already exist within Māori practices and philosophies.          

This Thesis, therefore, investigates alternative processes of filming that have developed from a Kaupapa Māori perspective through practical filming experience.  An historical overview of the relationship between Māori, media and filming practices have been provided to give context to this discussion.  The application of Kaupapa Māori processes to film was considered through the use of Marae protocol and philosophies. The application of these concepts was supported by the creative research which was utilised by referencing specific examples. The reader is, therefore, instructed to refer to the DVD in the front of the thesis as referenced in the written text.

year: 2007