title: Current honey research at the University of Waikato

authors: Molan, Peter C.

subjects: biology

abstract: To put what has become a very large part of our research into context, I briefly outline the history of the chance finding by a PhD student at the University of Dresden in 2005 that few samples of manuka honey examined in a survey of foodstuffs contained an exceptionally high level of MGO, which lead to the proposal in 2006 that MGO, is the antibacterial component of manuka honey.  It was the bringing of this to the attention of the world by Manuka Health in July 2007 that led to six of our research group having to work very hard for the past year on gaining an understanding of how MGO forms in manuka honey, seeking scientific substance can be safely consumed when it is in manuka honey, and that when in contact with wound tissues at the high levels at which it occurs in undiluted honey, it does not interfere with the healing process.

text: Current honey research at the University of Waikato To put what has become a very large part of our research into context, I briefly outline the history of the chance finding by a PhD student at the University of Dresden in 2005 that few samples of manuka honey examined in a survey of foodstuffs contained an exceptionally high level of MGO, which lead to the proposal in 2006 that MGO, is the antibacterial component of manuka honey.  It was the bringing of this to the attention of the world by Manuka Health in July 2007 that led to six of our research group having to work very hard for the past year on gaining an understanding of how MGO forms in manuka honey, seeking scientific substance can be safely consumed when it is in manuka honey, and that when in contact with wound tissues at the high levels at which it occurs in undiluted honey, it does not interfere with the healing process.

year: 2008

title: Sensitive pyroclastic soils in the Bay of Plenty, New Zealand: microstructure to failure mechanisms

authors: Moon, Vicki G.

subjects: sensitive soil

abstract: Sensitive soils derived from weathered rhyolitic pyroclastic materials are associated with many landslides in the Bay of Plenty. Undrained, consolidated static triaxial tests show contractive p’-q’ plots, strain-softening stress-strain behaviour coupled with rising pore water pressures, shear band formation after peak strength, and considerable strain softening. Cyclic triaxial tests confirm brittle failure and extensive softening of the soil. Pore pressure gradients developed during shearing initiate collapse of clay microstructures into shear zones; further excess pore pressure generation in the shear zone leads to progressive failure. Halloysite, a low-activity clay mineral, is associated with sensitive layers within the pyroclastic sequences. Mushroom cap–shaped spheroidal halloysite results in weak short-range interactions between exposed clay surfaces on incomplete spheroids. This weak bonding allows disassociation of clay aggregates during slope failure, leading to strain softening and the development of flow post-failure.

text: Sensitive pyroclastic soils in the Bay of Plenty, New Zealand: microstructure to failure mechanisms Sensitive soils derived from weathered rhyolitic pyroclastic materials are associated with many landslides in the Bay of Plenty. Undrained, consolidated static triaxial tests show contractive p’-q’ plots, strain-softening stress-strain behaviour coupled with rising pore water pressures, shear band formation after peak strength, and considerable strain softening. Cyclic triaxial tests confirm brittle failure and extensive softening of the soil. Pore pressure gradients developed during shearing initiate collapse of clay microstructures into shear zones; further excess pore pressure generation in the shear zone leads to progressive failure. Halloysite, a low-activity clay mineral, is associated with sensitive layers within the pyroclastic sequences. Mushroom cap–shaped spheroidal halloysite results in weak short-range interactions between exposed clay surfaces on incomplete spheroids. This weak bonding allows disassociation of clay aggregates during slope failure, leading to strain softening and the development of flow post-failure.

year: 2017

title: Lake Rotokakahi: The kakahi (Hyridella menziesi) in a general framework of lake health

authors: Butterworth, Joseph

subjects: Rotokakahi

abstract: Lake Rotokakahi is a mesotrophic lake located within the Rotorua Lakes District, North Island, New Zealand. Under the legal guardianship of the Tuhourangi and Ngati Tumatawera tribes of Te Arawa it has remained closed to the public since 1948. 

Lake Rotokakahi was last monitored regularly in 1996 under the Environment Bay of Plenty (EBOP) water quality monitoring programme with only the lake outlet (Te Wairoa Stream) being monitored since that time. Water quality data collected up to 1996 suggests that there may be degradation of water quality in the lake, as indicated by declining levels of dissolved oxygen in the bottom waters.

 Lake Rotokakahi steeped in historical significance, as well as having major cultural and recreational values was well known for its abundant resources and as the name suggests, particularly for its massive supply of the freshwater mussel or kakahi (Hyridella menziesi). Freshwater mussel species worldwide are in decline however little is known on factors controlling kakahi abundance and distribution. 

The overarching objective of this thesis is update water quality data last monitored in Lake Rotokakahi in 1996 while also identifying key environmental variables thought to influence kakahi populations.  This objective is underpinned by a number of aims that include:
 	Establishment of a 12-13 month water quality programme within Lake Rotokakahi so that data is obtained for comparisons with previous water quality data (pre-1997) to allow assessment of whether there have been water quality changes in the lake.
 	Conduct a population survey of the resident kakahi population examining possible environmental factors influencing their populations.
 	Present an oral history of Lake Rotokakahi focusing on its historical significance, water quality, and collection of kairoto (food collected form lakes).

from the 18 September 2006 to 14 September 2007 monthly water sampling was carried out at a mid lake station, the lake outflow and inflow for measures of nutrients, phytoplankton, zooplankton and chlorophyll a. Vertical profiles of temperature dissolved oxygen and chlorophyll fluorescence were also taken on various part of Lake Rotokakahi.

A lengthened period of anoxia in the bottom waters during thermal stratification was recorded with increased levels of chlorophyll a in winter and reduced secchi disk depth indicating an increase in phytoplankton biomass. Nutrient concentrations remain moderate relative to historical data. On going water quality monitoring on Lake Rotokakahi is recommended to further evaluate the extent of which water quality change is occurring. This will provide a better understanding of how Lake Rotokakahi can be best managed to further preserve the lake.

On 1 March and 20 April kakahi were sampled at five sites. Large kakahi densities were distributed predominantly in depths above the hypolimnion. Chlorophyll a fluorescence and dissolved oxygen were found to be the best correlates for kakahi density and biomass respectively. Low dissolved oxygen concentrations in the hypolimnion are thought to restrict kakahi distributions to above the thermocline in periods of hypolimnetic anoxia.

text: Lake Rotokakahi: The kakahi (Hyridella menziesi) in a general framework of lake health Lake Rotokakahi is a mesotrophic lake located within the Rotorua Lakes District, North Island, New Zealand. Under the legal guardianship of the Tuhourangi and Ngati Tumatawera tribes of Te Arawa it has remained closed to the public since 1948. 

Lake Rotokakahi was last monitored regularly in 1996 under the Environment Bay of Plenty (EBOP) water quality monitoring programme with only the lake outlet (Te Wairoa Stream) being monitored since that time. Water quality data collected up to 1996 suggests that there may be degradation of water quality in the lake, as indicated by declining levels of dissolved oxygen in the bottom waters.

 Lake Rotokakahi steeped in historical significance, as well as having major cultural and recreational values was well known for its abundant resources and as the name suggests, particularly for its massive supply of the freshwater mussel or kakahi (Hyridella menziesi). Freshwater mussel species worldwide are in decline however little is known on factors controlling kakahi abundance and distribution. 

The overarching objective of this thesis is update water quality data last monitored in Lake Rotokakahi in 1996 while also identifying key environmental variables thought to influence kakahi populations.  This objective is underpinned by a number of aims that include:
 	Establishment of a 12-13 month water quality programme within Lake Rotokakahi so that data is obtained for comparisons with previous water quality data (pre-1997) to allow assessment of whether there have been water quality changes in the lake.
 	Conduct a population survey of the resident kakahi population examining possible environmental factors influencing their populations.
 	Present an oral history of Lake Rotokakahi focusing on its historical significance, water quality, and collection of kairoto (food collected form lakes).

from the 18 September 2006 to 14 September 2007 monthly water sampling was carried out at a mid lake station, the lake outflow and inflow for measures of nutrients, phytoplankton, zooplankton and chlorophyll a. Vertical profiles of temperature dissolved oxygen and chlorophyll fluorescence were also taken on various part of Lake Rotokakahi.

A lengthened period of anoxia in the bottom waters during thermal stratification was recorded with increased levels of chlorophyll a in winter and reduced secchi disk depth indicating an increase in phytoplankton biomass. Nutrient concentrations remain moderate relative to historical data. On going water quality monitoring on Lake Rotokakahi is recommended to further evaluate the extent of which water quality change is occurring. This will provide a better understanding of how Lake Rotokakahi can be best managed to further preserve the lake.

On 1 March and 20 April kakahi were sampled at five sites. Large kakahi densities were distributed predominantly in depths above the hypolimnion. Chlorophyll a fluorescence and dissolved oxygen were found to be the best correlates for kakahi density and biomass respectively. Low dissolved oxygen concentrations in the hypolimnion are thought to restrict kakahi distributions to above the thermocline in periods of hypolimnetic anoxia.

year: 2008