title: Can oxygen stable isotopes be used to track precipitation moisture

authors: Amesbury, Matthew J.

subjects: stable isotopes

abstract: Variations in the isotopic composition of precipitation are determined by fractionation processes which occur during temperature- and humidity-dependent phase changes associated with evaporation and condensation. Oxygen stable isotope ratios have therefore been frequently used as a source of palaeoclimate data from a variety of proxy archives, which integrate this signal over time. Applications from ombrotrophic peatlands, where the source water used in cellulose synthesis is derived solely from precipitation, have been mostly limited to Northern Hemisphere Sphagnum-dominated bogs, with few in the Southern Hemisphere or in peatlands dominated by vascular plants. New Zealand (NZ) provides an ideal location to undertake empirical research into oxygen isotope fractionation in vascular peatlands because single taxon analysis can be easily carried out, in particular using the preserved root matrix of the restionaceous wire rush (Empodisma spp.) that forms deep Holocene peat deposits throughout the country. Furthermore, large gradients are observed in the mean isotopic composition of precipitation across NZ, caused primarily by the relative influence of different climate modes. Here, we test whether δ18O of Empodisma α-cellulose from ombrotrophic restiad peatlands in NZ can provide a methodology for developing palaeoclimate records of past precipitation δ18O. Surface plant, water and precipitation samples were taken over spatial (six sites spanning >10◦ latitude) and temporal (monthly measurements over one year) gradients. A link between the isotopic composition of root-associated water, the most likely source water for plant growth, and precipitation in both datasets was found. Back-trajectory modelling of precipitation moisture source for rain days prior to sampling showed clear seasonality in the temporal data that was reflected in root-associated water. The link between source water and plant cellulose was less clear, although mechanistic modelling predicted mean cellulose values within published error margins for both datasets. Improved physiological understanding and modelling of δ18O in restiad peatlands should enable use of this approach as a new source of palaeoclimate data to reconstruct changes in past atmospheric circulation.

text: Can oxygen stable isotopes be used to track precipitation moisture Variations in the isotopic composition of precipitation are determined by fractionation processes which occur during temperature- and humidity-dependent phase changes associated with evaporation and condensation. Oxygen stable isotope ratios have therefore been frequently used as a source of palaeoclimate data from a variety of proxy archives, which integrate this signal over time. Applications from ombrotrophic peatlands, where the source water used in cellulose synthesis is derived solely from precipitation, have been mostly limited to Northern Hemisphere Sphagnum-dominated bogs, with few in the Southern Hemisphere or in peatlands dominated by vascular plants. New Zealand (NZ) provides an ideal location to undertake empirical research into oxygen isotope fractionation in vascular peatlands because single taxon analysis can be easily carried out, in particular using the preserved root matrix of the restionaceous wire rush (Empodisma spp.) that forms deep Holocene peat deposits throughout the country. Furthermore, large gradients are observed in the mean isotopic composition of precipitation across NZ, caused primarily by the relative influence of different climate modes. Here, we test whether δ18O of Empodisma α-cellulose from ombrotrophic restiad peatlands in NZ can provide a methodology for developing palaeoclimate records of past precipitation δ18O. Surface plant, water and precipitation samples were taken over spatial (six sites spanning >10◦ latitude) and temporal (monthly measurements over one year) gradients. A link between the isotopic composition of root-associated water, the most likely source water for plant growth, and precipitation in both datasets was found. Back-trajectory modelling of precipitation moisture source for rain days prior to sampling showed clear seasonality in the temporal data that was reflected in root-associated water. The link between source water and plant cellulose was less clear, although mechanistic modelling predicted mean cellulose values within published error margins for both datasets. Improved physiological understanding and modelling of δ18O in restiad peatlands should enable use of this approach as a new source of palaeoclimate data to reconstruct changes in past atmospheric circulation.

year: 2015-08-14

title: Talking the talk: New Zealanders remember the Vietnam War

authors: Challinor, Deborah A.

abstract: From 1964 to 1972, almost 4,000 New Zealand military personnel served in Vietnam, most in an active combat role. The war was a politically and socially divisive issue for New Zealanders in general, but it can be argued that its greatest impact has been on the veterans themselves. This thesis will establish, analyse and explain what some of these New Zealander remember about the Vietnam War, why they remember it this way, and what the factors are which may have influenced this. Oral testimony has been chosen as the main form of evidence.

The thesis is divided into a detailed discussion of the methodology used in relation to the collection and analysis of the oral testimonies, a short introduction to some of the New Zealand Vietnam veterans interviewed, ten chapters which present the evidence, and a final section which analyses the evidence and suggests conclusions. References to the Australian and American experiences during and after Vietnam are made where relevant to provide a comparative element and to establish context.

Chapter One is an introduction to the origins, components and commemoration of New Zealand’s military traditions from the Boer War to the conflicts in Malaya and Borneo during the 1950s and 1960s. Chapter Two summarises the political and diplomatic rationale for New Zealand’s involvement in Vietnam and the military contribution that New Zealand made. Chapters Three to Eight recount why New Zealanders went to Vietnam and what they found there, allied relationships, the culture of the New Zealand soldier in Vietnam, the experience of combat and associated psychological and behavioural responses, and coping and stress release mechanisms including the use of alcohol, sex and aggression. Chapter Nine relates the experiences of veterans when they returned home, and Chapter Ten is a discussion of how the Vietnam War is remembered in New Zealand today. Much of the analysis of the evidence is presented in the final section, as are some conclusions.

Although only a small percentage of the New Zealanders who served in Vietnam are represented here, some patterns relating to how and why they remember Vietnam can be established. It is suggested that several versions of New Zealand’s traditional military mythology have had a significant impact in relation to some veterans’ motivations for going to war, what they experienced during their service and, in particular, the experience of coming home. The mythologies of the American and Australian experiences of Vietnam may also be an influencing factor. This thesis is intended to offer a brief glimpse of the dynamic relationship between the above factors and the process and construction of memory.

text: Talking the talk: New Zealanders remember the Vietnam War From 1964 to 1972, almost 4,000 New Zealand military personnel served in Vietnam, most in an active combat role. The war was a politically and socially divisive issue for New Zealanders in general, but it can be argued that its greatest impact has been on the veterans themselves. This thesis will establish, analyse and explain what some of these New Zealander remember about the Vietnam War, why they remember it this way, and what the factors are which may have influenced this. Oral testimony has been chosen as the main form of evidence.

The thesis is divided into a detailed discussion of the methodology used in relation to the collection and analysis of the oral testimonies, a short introduction to some of the New Zealand Vietnam veterans interviewed, ten chapters which present the evidence, and a final section which analyses the evidence and suggests conclusions. References to the Australian and American experiences during and after Vietnam are made where relevant to provide a comparative element and to establish context.

Chapter One is an introduction to the origins, components and commemoration of New Zealand’s military traditions from the Boer War to the conflicts in Malaya and Borneo during the 1950s and 1960s. Chapter Two summarises the political and diplomatic rationale for New Zealand’s involvement in Vietnam and the military contribution that New Zealand made. Chapters Three to Eight recount why New Zealanders went to Vietnam and what they found there, allied relationships, the culture of the New Zealand soldier in Vietnam, the experience of combat and associated psychological and behavioural responses, and coping and stress release mechanisms including the use of alcohol, sex and aggression. Chapter Nine relates the experiences of veterans when they returned home, and Chapter Ten is a discussion of how the Vietnam War is remembered in New Zealand today. Much of the analysis of the evidence is presented in the final section, as are some conclusions.

Although only a small percentage of the New Zealanders who served in Vietnam are represented here, some patterns relating to how and why they remember Vietnam can be established. It is suggested that several versions of New Zealand’s traditional military mythology have had a significant impact in relation to some veterans’ motivations for going to war, what they experienced during their service and, in particular, the experience of coming home. The mythologies of the American and Australian experiences of Vietnam may also be an influencing factor. This thesis is intended to offer a brief glimpse of the dynamic relationship between the above factors and the process and construction of memory.

year: 1998

title: Call and response: Taika Waititi’s ‘Boy’

authors: Perrott, Lisa

subjects: Waititi's film

abstract: Lisa Perrott examines how the construction of Waititi's latest film might engender complex, nuanced responses from audiences.

text: Call and response: Taika Waititi’s ‘Boy’ Lisa Perrott examines how the construction of Waititi's latest film might engender complex, nuanced responses from audiences.

year: 2010