title: Fish health changes in Lake Okaro, New Zealand: effects of nutrient remediation, season or eutrophication?

authors: Landman, Michael J.

subjects: eutrophication

abstract: The purpose of this investigation was to measure the in situ health of selected biota with respect to a large-scale application of an aluminiumamended zeolite (Z2G1) in Lake Okaro, New Zealand. We hypothesized that, based on previous laboratory toxicity testing, the Z2G1 application would have minimal or no significant health effects on lake fauna. To test this hypothesis, two sampling events were timed around the Z2G1 application to examine the health of two finfish species (Oncorhynchus mykiss and Gobiomorphus cotidianus) and crayfish (Paranephrops planifrons). Additionally, the same species were sampled from the neighbouring Lake Rerewhakaaitu in order to delineate seasonal and lake-specific effects. A general lack of aluminium accumulation in animal tissues following the application indicated that Z2G1-derived aluminium was not readily bioavailable. An unexplained osmoregulatory disturbance, indicated by increased blood plasma ion concentrations in Lake Okaro trout, was observed following the application, but could not be directly attributed to Z2G1 exposure. Changes in fish haematology over time and between lake populations were interpreted as physiological responses to seasonal changes in lake conditions. Using a broad range of specific and non-specific endpoints it was concluded that there were no obvious negative impacts on fish health resulting from Z2G1 exposure.

text: Fish health changes in Lake Okaro, New Zealand: effects of nutrient remediation, season or eutrophication? The purpose of this investigation was to measure the in situ health of selected biota with respect to a large-scale application of an aluminiumamended zeolite (Z2G1) in Lake Okaro, New Zealand. We hypothesized that, based on previous laboratory toxicity testing, the Z2G1 application would have minimal or no significant health effects on lake fauna. To test this hypothesis, two sampling events were timed around the Z2G1 application to examine the health of two finfish species (Oncorhynchus mykiss and Gobiomorphus cotidianus) and crayfish (Paranephrops planifrons). Additionally, the same species were sampled from the neighbouring Lake Rerewhakaaitu in order to delineate seasonal and lake-specific effects. A general lack of aluminium accumulation in animal tissues following the application indicated that Z2G1-derived aluminium was not readily bioavailable. An unexplained osmoregulatory disturbance, indicated by increased blood plasma ion concentrations in Lake Okaro trout, was observed following the application, but could not be directly attributed to Z2G1 exposure. Changes in fish haematology over time and between lake populations were interpreted as physiological responses to seasonal changes in lake conditions. Using a broad range of specific and non-specific endpoints it was concluded that there were no obvious negative impacts on fish health resulting from Z2G1 exposure.

year: 2011

title: The effects of irrigation on soil carbon and nitrogen stocks of pumice soils

authors: Millar, Jamie Alexandra

subjects: Carbon

abstract: The use of irrigation has become important for sustaining the production of food, fibre and biofuel. In New Zealand (NZ), irrigation of pastures is increasing in areas with seasonal water deficits, such as the Central North Island. Nationally, there was an estimated 794,443 ha of land under irrigation in 2017. A synthesis of the literature showed that soil C and N stocks response to irrigation was dependent on the initial soil organic matter content and climatic zone. However, most of the literature focused on arid/semiarid climate regimes where cereals and other crops were grown, with few studies conducted on pastoral land in temperate climates. However Mudge et al. (2017), measured a decrease in soil carbon (C) (6.99 t C ha⁻¹) and nitrogen (N) (0.58 t N ha⁻¹) to 0.3 m depth in irrigated grazed pastures relative to adjacent non-irrigated grazed pastures. Of their 34 paired sites across NZ, only seven were sampled from the Pumice Soil order, which was insufficient to determine whether this soil order was vulnerable to soil C and N loss.
The main objective of this thesis was to compare the total soil C and N stocks of irrigated and non-irrigated Pumice Soils. A second objective was to determine where there were any trends in changes in soil C and N in relation to irrigation duration.
Fourteen paired irrigated and adjacent non-irrigated sites were sampled in the Reporoa Basin, north of Taupo and soil C and N stocks were measured accounting for differences in soil bulk density. Most sites where sampled to 0.6 m depth, however, due to high water tables and buried soils, some sites were only sampled to 0.4 m or 0.5 m depth. One site was omitted from statistical analysis due to high residuals (F11-35) and was considered an outlier that potentially represented a poorly matched pair of sites. On average, for the remaining 13 paired sites, irrigated soils had significantly (P < 0.05) lower soil C stocks (5.93 t C ha⁻¹) to 0.2 m depth and lower N stocks (0.24 t N ha⁻¹) to 0.1 m depth in comparison to adjacent non-irrigated soils. When considering the full depth of the sampled soils (0-0.6 m), there were no significant changes in soil C and N stocks (P > 0.05). Using this coring method, I was able to detect a change of about 6.9 % in soil C stocks and a 4.8 % in soil N stocks. This study also found no evidence of a relationship between soil response to irrigation and duration of irrigation.
With the loss of soil C and N under irrigation comes potential release of CO₂ to the atmosphere and N leaching into surrounding water bodies. Based on the findings in this thesis, there is a need for further investigation on the effects of irrigation for different Soil Orders. This research will aid farmers in understanding their land management on-farm and inform them of their potential effects on greenhouse gas emissions on a national scale.

text: The effects of irrigation on soil carbon and nitrogen stocks of pumice soils The use of irrigation has become important for sustaining the production of food, fibre and biofuel. In New Zealand (NZ), irrigation of pastures is increasing in areas with seasonal water deficits, such as the Central North Island. Nationally, there was an estimated 794,443 ha of land under irrigation in 2017. A synthesis of the literature showed that soil C and N stocks response to irrigation was dependent on the initial soil organic matter content and climatic zone. However, most of the literature focused on arid/semiarid climate regimes where cereals and other crops were grown, with few studies conducted on pastoral land in temperate climates. However Mudge et al. (2017), measured a decrease in soil carbon (C) (6.99 t C ha⁻¹) and nitrogen (N) (0.58 t N ha⁻¹) to 0.3 m depth in irrigated grazed pastures relative to adjacent non-irrigated grazed pastures. Of their 34 paired sites across NZ, only seven were sampled from the Pumice Soil order, which was insufficient to determine whether this soil order was vulnerable to soil C and N loss.
The main objective of this thesis was to compare the total soil C and N stocks of irrigated and non-irrigated Pumice Soils. A second objective was to determine where there were any trends in changes in soil C and N in relation to irrigation duration.
Fourteen paired irrigated and adjacent non-irrigated sites were sampled in the Reporoa Basin, north of Taupo and soil C and N stocks were measured accounting for differences in soil bulk density. Most sites where sampled to 0.6 m depth, however, due to high water tables and buried soils, some sites were only sampled to 0.4 m or 0.5 m depth. One site was omitted from statistical analysis due to high residuals (F11-35) and was considered an outlier that potentially represented a poorly matched pair of sites. On average, for the remaining 13 paired sites, irrigated soils had significantly (P < 0.05) lower soil C stocks (5.93 t C ha⁻¹) to 0.2 m depth and lower N stocks (0.24 t N ha⁻¹) to 0.1 m depth in comparison to adjacent non-irrigated soils. When considering the full depth of the sampled soils (0-0.6 m), there were no significant changes in soil C and N stocks (P > 0.05). Using this coring method, I was able to detect a change of about 6.9 % in soil C stocks and a 4.8 % in soil N stocks. This study also found no evidence of a relationship between soil response to irrigation and duration of irrigation.
With the loss of soil C and N under irrigation comes potential release of CO₂ to the atmosphere and N leaching into surrounding water bodies. Based on the findings in this thesis, there is a need for further investigation on the effects of irrigation for different Soil Orders. This research will aid farmers in understanding their land management on-farm and inform them of their potential effects on greenhouse gas emissions on a national scale.

year: 2018

title: Contemporary attitudes to traditional facial ta moko: A working paper

authors: Rua, Mohi

subjects: Maori

abstract: Until it came under serious attack from nineteenth century missionaries, ta moko was an
integral part of traditional Maori society. Facial moko conveyed important information about
identity, whakapapa and status. The process of receiving a moko was tapu and highly regulated.
Recent years have seen an increase in the number of Maori receiving ta moko. Moko have been
seen as a symbol of Maori pride and identity and have often been associated with political
activism. This study set out to investigate the contemporary meaning of ta moko, the reactions
wearers encounter from others and the ways wearers cope with those reactions.
Three case studies are presented. These show that the issues of personal identity and
whakapapa were central to the meaning wearers attached to their moko. Receiving a moko was
often associated with significant personal changes and an increased political commitment to
Maori self determination. On the whole, positive reactions were more common than negative
reactions but wearers did find themselves subjected to racist and antagonistic responses.
Wearing moko was also reported to mean that others, particularly other Maori, placed certain
expectations on the wearer, notably to be fluent in te reo and to be able to exercise leadership.
Participants considered that there was a need for education about the significance of ta moko
and recommended that those contemplating receiving a moko ensure that they are reasonably
fluent in te reo.

text: Contemporary attitudes to traditional facial ta moko: A working paper Until it came under serious attack from nineteenth century missionaries, ta moko was an
integral part of traditional Maori society. Facial moko conveyed important information about
identity, whakapapa and status. The process of receiving a moko was tapu and highly regulated.
Recent years have seen an increase in the number of Maori receiving ta moko. Moko have been
seen as a symbol of Maori pride and identity and have often been associated with political
activism. This study set out to investigate the contemporary meaning of ta moko, the reactions
wearers encounter from others and the ways wearers cope with those reactions.
Three case studies are presented. These show that the issues of personal identity and
whakapapa were central to the meaning wearers attached to their moko. Receiving a moko was
often associated with significant personal changes and an increased political commitment to
Maori self determination. On the whole, positive reactions were more common than negative
reactions but wearers did find themselves subjected to racist and antagonistic responses.
Wearing moko was also reported to mean that others, particularly other Maori, placed certain
expectations on the wearer, notably to be fluent in te reo and to be able to exercise leadership.
Participants considered that there was a need for education about the significance of ta moko
and recommended that those contemplating receiving a moko ensure that they are reasonably
fluent in te reo.

year: 1999