title: Managing denitrification in human-dominated landscapes

authors: Schipper, Louis A.

subjects: N

abstract: Increases in food supply and fossil fuel consumption are among the hallmarks of the 20th century. These changes share a common characteristic – they both contribute to an excess supply of plant-available (i.e., reactive) nitrogen – with negative consequences to ecosystems and water supplies across the globe. While there are vast quantities of di-nitrogen gas (N₂) in the atmosphere, this form of N is unavailable (termed unreactive N) to the vast majority of biological life (Galloway et al., 2003). Globally, this unreactive N can be converted to reactive N by four major processes: N-fixing microorganisms (often in symbiotic association with plants, 140 TgNyear⁻¹), industrial fertilizer production (125 TgNyear⁻¹), fossil fuel combustion (25 TgNyear⁻¹), and lightning (5 TgNyear⁻¹) (Schlesinger, 2009). The benefits of increased food production by use of N inputs are clear. World economies also continue to rely on fossil fuels for transport and fertilizer production. As with many biogeochemical processes that are manipulated at global scales, increased N inputs has adverse and unintended consequences (Galloway et al., 2008).

text: Managing denitrification in human-dominated landscapes Increases in food supply and fossil fuel consumption are among the hallmarks of the 20th century. These changes share a common characteristic – they both contribute to an excess supply of plant-available (i.e., reactive) nitrogen – with negative consequences to ecosystems and water supplies across the globe. While there are vast quantities of di-nitrogen gas (N₂) in the atmosphere, this form of N is unavailable (termed unreactive N) to the vast majority of biological life (Galloway et al., 2003). Globally, this unreactive N can be converted to reactive N by four major processes: N-fixing microorganisms (often in symbiotic association with plants, 140 TgNyear⁻¹), industrial fertilizer production (125 TgNyear⁻¹), fossil fuel combustion (25 TgNyear⁻¹), and lightning (5 TgNyear⁻¹) (Schlesinger, 2009). The benefits of increased food production by use of N inputs are clear. World economies also continue to rely on fossil fuels for transport and fertilizer production. As with many biogeochemical processes that are manipulated at global scales, increased N inputs has adverse and unintended consequences (Galloway et al., 2008).

year: 2010

title: In situ collection and preservation of intact Microcystis colonies to assess population diversity and microcystin quotas

authors: Puddick, Jonathan

subjects: Science & Technology

abstract: Understanding of colony specific properties of cyanobacteria in the natural environment has been challenging because sampling methods disaggregate colonies and there are often delays before they can be isolated and preserved. Microcystis is a ubiquitous cyanobacteria that forms large colonies in situ and often produces microcystins, a potent hepatotoxin. In the present study a new cryo-sampling technique was used to collect intact Microcystis colonies in situ by embedding them in a sheet of ice. Thirty-two of these Microcystis colonies were investigated with image analysis, liquid chromatography-mass spectrometry, quantitative polymerase chain reaction and high-throughput sequencing to assess their volume, microcystin quota and internal transcribed spacer (ITS) genotype diversity. Microcystin quotas were positively correlated to colony volume (R² = 0.32; p = 0.004). Individual colonies had low Microcystis ITS genotype diversity and one ITS operational taxonomic unit predominated in all samples. This study demonstrates the utility of the cryo-sampling method to enhance the understanding of colony-specific properties of cyanobacteria with higher precision than previously possible.

text: In situ collection and preservation of intact Microcystis colonies to assess population diversity and microcystin quotas Understanding of colony specific properties of cyanobacteria in the natural environment has been challenging because sampling methods disaggregate colonies and there are often delays before they can be isolated and preserved. Microcystis is a ubiquitous cyanobacteria that forms large colonies in situ and often produces microcystins, a potent hepatotoxin. In the present study a new cryo-sampling technique was used to collect intact Microcystis colonies in situ by embedding them in a sheet of ice. Thirty-two of these Microcystis colonies were investigated with image analysis, liquid chromatography-mass spectrometry, quantitative polymerase chain reaction and high-throughput sequencing to assess their volume, microcystin quota and internal transcribed spacer (ITS) genotype diversity. Microcystin quotas were positively correlated to colony volume (R² = 0.32; p = 0.004). Individual colonies had low Microcystis ITS genotype diversity and one ITS operational taxonomic unit predominated in all samples. This study demonstrates the utility of the cryo-sampling method to enhance the understanding of colony-specific properties of cyanobacteria with higher precision than previously possible.

year: 2019

title: Reducing our prison population: Past failures and new approaches

authors: Tauri, Juan Marcellus

abstract: Earlier this year the Minister of Justice, Andrew Little announced the latest in a long line of reviews, taxpayer-funded summits and inter-agency, ‘wholeof-government’ projects stretching back to the late-1980s, all aimed in some form or other, at making the criminal justice system more ‘safe’ and ‘effective’. Officially launched at a summit held in Porirua in August 2018, the aim of the latest review is to reduce New Zealand’s prison muster by 30% over the next 15 years. And unsurprisingly, given our significant over-representation in prisons, a specific focus of the review is on identifying ways to significantly reduce Māori over-representation in the prison population. This commentary represents a modest offering in response to the current government’s stated aim of making the justice system safer and more effective, and to reduce the prison muster, and it is based on two core arguments, namely that successive governments and the public service have failed to reduce offending and imprisonment and that successful solutions require community empowerment and government/public service accountability.

text: Reducing our prison population: Past failures and new approaches Earlier this year the Minister of Justice, Andrew Little announced the latest in a long line of reviews, taxpayer-funded summits and inter-agency, ‘wholeof-government’ projects stretching back to the late-1980s, all aimed in some form or other, at making the criminal justice system more ‘safe’ and ‘effective’. Officially launched at a summit held in Porirua in August 2018, the aim of the latest review is to reduce New Zealand’s prison muster by 30% over the next 15 years. And unsurprisingly, given our significant over-representation in prisons, a specific focus of the review is on identifying ways to significantly reduce Māori over-representation in the prison population. This commentary represents a modest offering in response to the current government’s stated aim of making the justice system safer and more effective, and to reduce the prison muster, and it is based on two core arguments, namely that successive governments and the public service have failed to reduce offending and imprisonment and that successful solutions require community empowerment and government/public service accountability.

year: 2019