title: Discovery of halloysite books in a ~270,000 year-old buried tephra deposit in northern New Zealand

authors: Wyatt, Justin Burns

abstract: As part of a wider study examining the geomechanical properties, especially sensitivity, of sequences of Quaternary pyroclastic and associated deposits and buried soils in the landslide-prone western Bay of Plenty area near Tauranga, eastern North Island, we examined the mineralogy of a pale pinkish-grey tephra deposit directly beneath non-welded, siliceous Te Ranga Ignimbrite (~2 m thick) in a ~25 m high cutting at Tauriko.

text: Discovery of halloysite books in a ~270,000 year-old buried tephra deposit in northern New Zealand As part of a wider study examining the geomechanical properties, especially sensitivity, of sequences of Quaternary pyroclastic and associated deposits and buried soils in the landslide-prone western Bay of Plenty area near Tauranga, eastern North Island, we examined the mineralogy of a pale pinkish-grey tephra deposit directly beneath non-welded, siliceous Te Ranga Ignimbrite (~2 m thick) in a ~25 m high cutting at Tauriko.

year: 2010-08-07

title: High Frequency Monitoring and Three-Dimensional Modelling of Temporal Variations in Water Quality of Lake Rotorua, New Zealand

authors: Zhang, Chenguang

subjects: Lake Rotorua

abstract: Over the last few decades, anthropogenic eutrophication has become a significant problem in New Zealand and other parts of the world. Lake Rotorua is located in the central North Island, New Zealand. It is a lake with significant historical, cultural and recreational values that has undergone anthropogenic eutrophication.

Lake Rotorua has been exposed to anthropogenic impacts through conversion of forested land to agricultural use within its catchment, and the discharge of domestic sewage into the lake. Cyanobacterial blooms have become a common occurrence in the lake each summer. These blooms not only reduce aesthetic appeal but also have potential to affect human health. Lake stratification and physical mixing events are the most important factors influencing nutrient availability and phytoplankton growth in Lake Rotorua.

The main objective of this study was to use high frequency monitoring data to investigate the significance of lake stratification events and how these events interact with the development of the cyanobacteria population and changes in nutrient concentrations in Lake Rotorua. The second objective was to use an ecological model to understand the relationship between physical, chemical and biological variables, and phytoplankton dynamics.

Data from a high frequency real-time water quality monitoring buoy was used as the basis for 12 sampling trips to Lake Rotorua timed around stratification and mixing events. Water samples were collected from five different sites for nutrient analysis, chlorophyll a analysis, and phytoplankton and zooplankton identification at depth intervals of 6 meters. Profiles were taken for temperature, dissolved oxygen and fluorescence. Total suspended solids and volatile suspended solids were also analysed. The data provided by the buoy, combined with additional sampling and measurements around stratification events, were used to calibrate a three-dimensional ecosystem model, ELCOM-CAEDYM.

Periods consisting of a few days of high solar radiation and low winds caused Lake Rotorua to become stratified between 26 January 2009 and 20 February 2009. During this stratification period the bottom waters became deoxygenated and there were large increases in of phosphorus and nitrogen concentrations in bottom waters, which were subsequently dispersed through the water column when the lake mixed again. Ammonium and phosphate were the dominant species of inorganic nitrogen and phosphorus in bottom waters during the periods of stratification. Upon mixing there was rapid growth of cyanobacteria (Microcystis sp. and Anabaena sp.). For the zooplankton community, copepod and rotifer densities increased significantly after the stratification event and replaced the previously dominant cladocerans.

In the study high frequency modelling with ELCOM-CADYM simulated the general trends of water temperature, dissolved oxygen and nutrient concentrations in Lake Rotorua. The model captured the water temperature fluctuation before, during, and after lake stratification as well as subsequent dissolved oxygen changes over time and space. Simulated nutrient concentrations were close to the field measurements, in particular NH4, TN and TP. Some issues occurred with high frequency simulations such as being unable to capture the strong fluctuations of lake surface temperature, and the magnitude of the decreases in dissolved oxygen under strong stratification.

text: High Frequency Monitoring and Three-Dimensional Modelling of Temporal Variations in Water Quality of Lake Rotorua, New Zealand Over the last few decades, anthropogenic eutrophication has become a significant problem in New Zealand and other parts of the world. Lake Rotorua is located in the central North Island, New Zealand. It is a lake with significant historical, cultural and recreational values that has undergone anthropogenic eutrophication.

Lake Rotorua has been exposed to anthropogenic impacts through conversion of forested land to agricultural use within its catchment, and the discharge of domestic sewage into the lake. Cyanobacterial blooms have become a common occurrence in the lake each summer. These blooms not only reduce aesthetic appeal but also have potential to affect human health. Lake stratification and physical mixing events are the most important factors influencing nutrient availability and phytoplankton growth in Lake Rotorua.

The main objective of this study was to use high frequency monitoring data to investigate the significance of lake stratification events and how these events interact with the development of the cyanobacteria population and changes in nutrient concentrations in Lake Rotorua. The second objective was to use an ecological model to understand the relationship between physical, chemical and biological variables, and phytoplankton dynamics.

Data from a high frequency real-time water quality monitoring buoy was used as the basis for 12 sampling trips to Lake Rotorua timed around stratification and mixing events. Water samples were collected from five different sites for nutrient analysis, chlorophyll a analysis, and phytoplankton and zooplankton identification at depth intervals of 6 meters. Profiles were taken for temperature, dissolved oxygen and fluorescence. Total suspended solids and volatile suspended solids were also analysed. The data provided by the buoy, combined with additional sampling and measurements around stratification events, were used to calibrate a three-dimensional ecosystem model, ELCOM-CAEDYM.

Periods consisting of a few days of high solar radiation and low winds caused Lake Rotorua to become stratified between 26 January 2009 and 20 February 2009. During this stratification period the bottom waters became deoxygenated and there were large increases in of phosphorus and nitrogen concentrations in bottom waters, which were subsequently dispersed through the water column when the lake mixed again. Ammonium and phosphate were the dominant species of inorganic nitrogen and phosphorus in bottom waters during the periods of stratification. Upon mixing there was rapid growth of cyanobacteria (Microcystis sp. and Anabaena sp.). For the zooplankton community, copepod and rotifer densities increased significantly after the stratification event and replaced the previously dominant cladocerans.

In the study high frequency modelling with ELCOM-CADYM simulated the general trends of water temperature, dissolved oxygen and nutrient concentrations in Lake Rotorua. The model captured the water temperature fluctuation before, during, and after lake stratification as well as subsequent dissolved oxygen changes over time and space. Simulated nutrient concentrations were close to the field measurements, in particular NH4, TN and TP. Some issues occurred with high frequency simulations such as being unable to capture the strong fluctuations of lake surface temperature, and the magnitude of the decreases in dissolved oxygen under strong stratification.

year: 2010

title: Ngā Pakanga mō Wāhi Tapu: Battles over sacred places

authors: Joseph, Robert

abstract: Wāhi tapu are the sacred places of Māori in Aotearoa New Zealand. All cultures have sacred sites such as cemeteries, significant battlefields, and places of spiritual significance. Standout examples internationally include the ‘Weeping Wall’ in the Holy Land, Stonehenge in Britain, Maraeātea in the Pacific, and Intihuatana at Macchu Picchu in Peru. But unlike these sites, wāhi tapu are rarely a visible structure but rather a site or area within the landscape with values so significant that restrictions are warranted. In law, wāhi tapu are defined as a ‘place of special significance according to tikanga Māori’
 and ‘a place sacred to Māori in the traditional, spiritual, religious, ritual, or mythological sense’.
As the aphorism above emphasises, Māori historically were willing to die for land (and for women of course!), and wāhi tapu are the most sacred of places. Many battles have been fought over actual or proposed transgressions of their sacredness. In earlier years, blood was shed and men did die; today battles tend to occur in the Environment Court, but are just as passionate. Recent decades have seen conflicts where wāhi tapu were threatened by new highways, railroads, airports, prisons, residential and commercial developments, wind farms, power stations and waste dumps.
In this chapter, I discuss a number of the battles that have been fought over the development or preservation of wāhi tapu from first European contact up until the present time. I highlight the growing legal recognition of tikanga Māori in relation to these sacred landscapes, and conclude with a proposed pragmatic solution for all New Zealanders when negotiating developments over wāhi tapu. Having a
background in law and tribal affiliations, I discuss these tensions from both legal and kaupapa Māori perspectives.

text: Ngā Pakanga mō Wāhi Tapu: Battles over sacred places Wāhi tapu are the sacred places of Māori in Aotearoa New Zealand. All cultures have sacred sites such as cemeteries, significant battlefields, and places of spiritual significance. Standout examples internationally include the ‘Weeping Wall’ in the Holy Land, Stonehenge in Britain, Maraeātea in the Pacific, and Intihuatana at Macchu Picchu in Peru. But unlike these sites, wāhi tapu are rarely a visible structure but rather a site or area within the landscape with values so significant that restrictions are warranted. In law, wāhi tapu are defined as a ‘place of special significance according to tikanga Māori’
 and ‘a place sacred to Māori in the traditional, spiritual, religious, ritual, or mythological sense’.
As the aphorism above emphasises, Māori historically were willing to die for land (and for women of course!), and wāhi tapu are the most sacred of places. Many battles have been fought over actual or proposed transgressions of their sacredness. In earlier years, blood was shed and men did die; today battles tend to occur in the Environment Court, but are just as passionate. Recent decades have seen conflicts where wāhi tapu were threatened by new highways, railroads, airports, prisons, residential and commercial developments, wind farms, power stations and waste dumps.
In this chapter, I discuss a number of the battles that have been fought over the development or preservation of wāhi tapu from first European contact up until the present time. I highlight the growing legal recognition of tikanga Māori in relation to these sacred landscapes, and conclude with a proposed pragmatic solution for all New Zealanders when negotiating developments over wāhi tapu. Having a
background in law and tribal affiliations, I discuss these tensions from both legal and kaupapa Māori perspectives.

year: 2011