title: Sediment aluminium content of Lake Okaro: 2021 monitoring survey

authors: Tempero, Grant Wayne

abstract: The application of aluminium salts such as polyaluminium chloride and aluminium sulphate has been widely used to assist in the remediation of eutrophic freshwater ecosystems. Aluminium binds to phosphorus, reducing its availability for phytoplankton growth, with the additional benefit that sediment phosphorus is reduced under anoxic lake conditions. Since 2013, alum (aluminium sulphate) has been applied twice per year to Lake Okaro to reduce dissolved reactive phosphorus availability. The lake’s annual Trophic Lake Index has decreased from 5.5 in the early 2000s to 4.5 in 2020. Alum dosing has resulted in the addition of 3.8 t of aluminium to the lake, however, the spatial distribution and sediment accumulation rate of alum derived aluminium has not been investigated.

The University of Waikato was contracted by the Bay of Plenty Regional Council to survey sediment aluminium concentrations in Lake Okaro to determine the distribution and accumulation of alum derived aluminium. In addition to sediment total aluminium content, the proportion of amorphous (non-crystalline) aluminium was assessed. Amorphous aluminium is the fraction of total aluminium able to adsorb dissolved phosphorus, sequestering it from uptake by phytoplankton. It was assumed that increased proportions of amorphous aluminium were primarily derived from alum dosing.

text: Sediment aluminium content of Lake Okaro: 2021 monitoring survey The application of aluminium salts such as polyaluminium chloride and aluminium sulphate has been widely used to assist in the remediation of eutrophic freshwater ecosystems. Aluminium binds to phosphorus, reducing its availability for phytoplankton growth, with the additional benefit that sediment phosphorus is reduced under anoxic lake conditions. Since 2013, alum (aluminium sulphate) has been applied twice per year to Lake Okaro to reduce dissolved reactive phosphorus availability. The lake’s annual Trophic Lake Index has decreased from 5.5 in the early 2000s to 4.5 in 2020. Alum dosing has resulted in the addition of 3.8 t of aluminium to the lake, however, the spatial distribution and sediment accumulation rate of alum derived aluminium has not been investigated.

The University of Waikato was contracted by the Bay of Plenty Regional Council to survey sediment aluminium concentrations in Lake Okaro to determine the distribution and accumulation of alum derived aluminium. In addition to sediment total aluminium content, the proportion of amorphous (non-crystalline) aluminium was assessed. Amorphous aluminium is the fraction of total aluminium able to adsorb dissolved phosphorus, sequestering it from uptake by phytoplankton. It was assumed that increased proportions of amorphous aluminium were primarily derived from alum dosing.

year: 2023

title: Editorial: Global change and Antarctic terrestrial biodiversity

authors: Hogg, Ian D.

subjects: Antarctic

abstract: Over the past 50 years, portions of Antarctica and the sub-Antarctic islands have experienced some of the most rapid increases in mean air temperatures on Earth. For example, recent data released by NASA have shown that mean annual air temperatures over the Western Antarctic Ice Sheet (WAIS) have already increased by roughly 1°C and more than 2°C in the maritime Antarctic (e.g. Turner et al. 2005). Over the same period, introductions of nonindigenous species have also continued to increase particularly in the sub-Antarctic islands (Frenot et al. 2005). While ongoing debate, often politically motivated, continues to dominate discussion of climate change and its impacts, it is virtually certain that temperature increases and species’ introductions will intensify and continue to influence Antarctic terrestrial ecosystems over the next 50 years. Other human activities such as increasing numbers of tourists and scientists will affect the present terrestrial systems as well as those newly revealed as a result of glacial melt. Collectively, these changes will influence Antarctica’s biodiversity and ecosystem functioning as well as the corresponding feedbacks to glaciers, freshwater systems and the atmosphere. Thus, it is urgent that we develop a strong knowledge base for Antarctic terrestrial ecosystems and use this to identify ecosystem change (NAS 2011).

text: Editorial: Global change and Antarctic terrestrial biodiversity Over the past 50 years, portions of Antarctica and the sub-Antarctic islands have experienced some of the most rapid increases in mean air temperatures on Earth. For example, recent data released by NASA have shown that mean annual air temperatures over the Western Antarctic Ice Sheet (WAIS) have already increased by roughly 1°C and more than 2°C in the maritime Antarctic (e.g. Turner et al. 2005). Over the same period, introductions of nonindigenous species have also continued to increase particularly in the sub-Antarctic islands (Frenot et al. 2005). While ongoing debate, often politically motivated, continues to dominate discussion of climate change and its impacts, it is virtually certain that temperature increases and species’ introductions will intensify and continue to influence Antarctic terrestrial ecosystems over the next 50 years. Other human activities such as increasing numbers of tourists and scientists will affect the present terrestrial systems as well as those newly revealed as a result of glacial melt. Collectively, these changes will influence Antarctica’s biodiversity and ecosystem functioning as well as the corresponding feedbacks to glaciers, freshwater systems and the atmosphere. Thus, it is urgent that we develop a strong knowledge base for Antarctic terrestrial ecosystems and use this to identify ecosystem change (NAS 2011).

year: 2011

title: Telomere length in early childhood is associated with sex and ethnicity

authors: Ly, Kien

subjects: Science & Technology

abstract: Telomeres are repetitive DNA sequences at the end of chromosomes that function to protect chromosomes from degradation. Throughout the life course, telomere length decreases with age and is influenced by environmental factors and health conditions. This study aimed to determine the relative telomere lengths in a diverse cohort of about 4000 four-year-old children in New Zealand. Linear regression was used to investigate the relationship between telomere length, child gender, ethnicity, paternal age and deprivation. We observed substantial variation in telomere length according to sex and self-identified ethnicity. Telomere length was longer in females compared to males (coefficient of 0.042, 95% confidence interval (CI) 0.024–0.060). European children had shorter telomere than both the indigenous Māori (coefficient of 0.03, CI 0.007–0.055) and Pacific children (coefficient of 0.15, CI 0.12–0.18). The data suggest that telomere lengths are highly variable and variability between individuals arise from early age, influenced partly by sex and ethnicity. Longer telomeres in indigenous Māori and Pacific children may reflect the heritability of telomere length in genetically less complex populations. This study increases our understanding of telomere dynamics in young children since the majority of telomere studies are conducted in adults.

text: Telomere length in early childhood is associated with sex and ethnicity Telomeres are repetitive DNA sequences at the end of chromosomes that function to protect chromosomes from degradation. Throughout the life course, telomere length decreases with age and is influenced by environmental factors and health conditions. This study aimed to determine the relative telomere lengths in a diverse cohort of about 4000 four-year-old children in New Zealand. Linear regression was used to investigate the relationship between telomere length, child gender, ethnicity, paternal age and deprivation. We observed substantial variation in telomere length according to sex and self-identified ethnicity. Telomere length was longer in females compared to males (coefficient of 0.042, 95% confidence interval (CI) 0.024–0.060). European children had shorter telomere than both the indigenous Māori (coefficient of 0.03, CI 0.007–0.055) and Pacific children (coefficient of 0.15, CI 0.12–0.18). The data suggest that telomere lengths are highly variable and variability between individuals arise from early age, influenced partly by sex and ethnicity. Longer telomeres in indigenous Māori and Pacific children may reflect the heritability of telomere length in genetically less complex populations. This study increases our understanding of telomere dynamics in young children since the majority of telomere studies are conducted in adults.

year: 2019