title: Carbon dioxide emissions and sediment organic carbon burials across a gradient of trophic state in eleven New Zealand lakes

authors: Santoso, Arianto B.

subjects: CO₂ flux

abstract: Lakes are known to be important to the global carbon balance as they are both CO₂ sources to the atmosphere and also accumulate large amounts of carbon in their sediment. CO₂ flux dynamics across the air–water interface in 11 lakes of varying trophic state in the Rotorua region, New Zealand, derived from measured alkalinity, pH and wind speed at given temperature, showed that lakes may shift from being atmospheric CO₂ sources to sinks due to seasonal changes in phytoplankton productivity and lake mixing dynamics. Decreases in trophic state (i.e. improved water quality) in some of the lakes over the eight-year monitoring period were associated with increased surface water CO₂ concentrations and, as a consequence, increased CO₂ flux to the atmosphere. Organic carbon content analysis of the bottom sediments revealed that lakes with high phytoplankton productivity, indicated by high chlorophyll a biomass, generally had high rates of carbon deposition to the sediments, but not all deposited carbon was permanently buried. Remineralization of the organic carbon accrued in productive lakes may potentially generate CO₂, as well as CH₄, which promotes these lakes to act as greenhouse gas emitters.

text: Carbon dioxide emissions and sediment organic carbon burials across a gradient of trophic state in eleven New Zealand lakes Lakes are known to be important to the global carbon balance as they are both CO₂ sources to the atmosphere and also accumulate large amounts of carbon in their sediment. CO₂ flux dynamics across the air–water interface in 11 lakes of varying trophic state in the Rotorua region, New Zealand, derived from measured alkalinity, pH and wind speed at given temperature, showed that lakes may shift from being atmospheric CO₂ sources to sinks due to seasonal changes in phytoplankton productivity and lake mixing dynamics. Decreases in trophic state (i.e. improved water quality) in some of the lakes over the eight-year monitoring period were associated with increased surface water CO₂ concentrations and, as a consequence, increased CO₂ flux to the atmosphere. Organic carbon content analysis of the bottom sediments revealed that lakes with high phytoplankton productivity, indicated by high chlorophyll a biomass, generally had high rates of carbon deposition to the sediments, but not all deposited carbon was permanently buried. Remineralization of the organic carbon accrued in productive lakes may potentially generate CO₂, as well as CH₄, which promotes these lakes to act as greenhouse gas emitters.

year: 2017

title: Isomerism of Complexes Containing Thiourea Dianion Ligands

authors: Spenceley, Jane Estelle

subjects: Thiourea

abstract: This thesis reports the synthesis and characterisation of eight new platinum thiourea complexes. Thiourea dianion complexes of the type (Ph₃P)₂PtSC(=NR)NPh, R=Me, Et, Prⁿ, Prⁱ, Buⁿ and (Ph₃P)₂PtSC(=NPh)NR R=Buͭ , p-tol, and the thiourea monoanion complex of the type [(Ph₃P)₂PtSC(=NEtH)NPh]⁺ were synthesised. This research confirms the prediction made by Henderson et al that asymmetrically substituted thiourea dianion complexes could form isomers. NMR studies show that the kinetically favoured isomer is formed initially, and then undergoes a solution phase isomerisation process to form the thermodynamically favoured isomer. Evidence that this isomerisation is affected by difference in substituent size and the energy difference between the two structures was obtained both experimentally, by use of NMR spectroscopy techniques, and theoretically using DFT calculations. Theoretically optimised geometries of each isomer allowed the calculation of ΔG(GPtrem-GPtadj) for each pair. NMR techniques were used to monitor the isomerisation process, which was clearly visible in both ¹H and ³¹P spectra. The relative substituent size, difference in energy between the two structures and rate of isomerisation appear to be proportional to each other. The greater the substituent size difference, the greater the difference in energy and faster the rate of isomerisation from the kinetically favoured isomer to the thermodynamically favoured isomer.

text: Isomerism of Complexes Containing Thiourea Dianion Ligands This thesis reports the synthesis and characterisation of eight new platinum thiourea complexes. Thiourea dianion complexes of the type (Ph₃P)₂PtSC(=NR)NPh, R=Me, Et, Prⁿ, Prⁱ, Buⁿ and (Ph₃P)₂PtSC(=NPh)NR R=Buͭ , p-tol, and the thiourea monoanion complex of the type [(Ph₃P)₂PtSC(=NEtH)NPh]⁺ were synthesised. This research confirms the prediction made by Henderson et al that asymmetrically substituted thiourea dianion complexes could form isomers. NMR studies show that the kinetically favoured isomer is formed initially, and then undergoes a solution phase isomerisation process to form the thermodynamically favoured isomer. Evidence that this isomerisation is affected by difference in substituent size and the energy difference between the two structures was obtained both experimentally, by use of NMR spectroscopy techniques, and theoretically using DFT calculations. Theoretically optimised geometries of each isomer allowed the calculation of ΔG(GPtrem-GPtadj) for each pair. NMR techniques were used to monitor the isomerisation process, which was clearly visible in both ¹H and ³¹P spectra. The relative substituent size, difference in energy between the two structures and rate of isomerisation appear to be proportional to each other. The greater the substituent size difference, the greater the difference in energy and faster the rate of isomerisation from the kinetically favoured isomer to the thermodynamically favoured isomer.

year: 2014

title: Cultural justice, ethics and teaching

authors: Nairn, Ray

subjects: Maori

abstract: Te Tiriti o Waitangi provides both a basis for cultural justice in this society and an explication of the term; each of the articles identifying a significant aspect of cultural justice. First, there is the guarantee to the Maori signatories that the Crown would protect their independence - tino rangatiratanga, (also read as authority, autonomy or self-determination) [Article II]. In Article III Maori are promised that they will also have the “Rights and Privileges of British subjects”. Finally, in Article I, Maori cede to the Crown the right to govern, to make laws to protect all peoples from the evil consequences of lawlessness. The 1835 Declaration of Independence located legislative authority in the Wakaminenga (the gathered rangatira meeting in Congress); and in 1840, in the context of the Crown promises, Maori authorised the Crown to exercise that authority. For Maori Te Tiriti specifies cultural justice for interactions between Maori and settlers in the new society. Maori are guaranteed the right to self-determination (and the economic and social resources to make that practical) in their relations with New Zealand society. They are also entitled to the same opportunities as other citizens. The latter rights, embodied in local legislation and international covenants to which we are signatory, are not alternatives to the prior right of Maori people to their (cultural) autonomy. The exercise of legislative and organisational authority must be exercised in a manner consistent with the promises which clearly requires consultation and negotiation with Maori.

text: Cultural justice, ethics and teaching Te Tiriti o Waitangi provides both a basis for cultural justice in this society and an explication of the term; each of the articles identifying a significant aspect of cultural justice. First, there is the guarantee to the Maori signatories that the Crown would protect their independence - tino rangatiratanga, (also read as authority, autonomy or self-determination) [Article II]. In Article III Maori are promised that they will also have the “Rights and Privileges of British subjects”. Finally, in Article I, Maori cede to the Crown the right to govern, to make laws to protect all peoples from the evil consequences of lawlessness. The 1835 Declaration of Independence located legislative authority in the Wakaminenga (the gathered rangatira meeting in Congress); and in 1840, in the context of the Crown promises, Maori authorised the Crown to exercise that authority. For Maori Te Tiriti specifies cultural justice for interactions between Maori and settlers in the new society. Maori are guaranteed the right to self-determination (and the economic and social resources to make that practical) in their relations with New Zealand society. They are also entitled to the same opportunities as other citizens. The latter rights, embodied in local legislation and international covenants to which we are signatory, are not alternatives to the prior right of Maori people to their (cultural) autonomy. The exercise of legislative and organisational authority must be exercised in a manner consistent with the promises which clearly requires consultation and negotiation with Maori.

year: 1993