title: Evaluating the influence of lake morphology, trophic status and diagenesis on geochemical profiles in lake sediments

authors: Trolle, Dennis

subjects: lake sediment

abstract: Recent geochemical studies provide evidence that changes in vertical distributions of nutrients in lake sediments are driven by anthropogenic activities, based primarily on trends of increasing concentrations in upper sediment layers. However, we show that vertical concentration profiles of carbon (C), nitrogen (N) and phosphorus (P) in lake sediments can be higher in the upper, most recently deposited sediment strata, driven largely by natural diagenetic processes and not eutrophication alone. We examined sediment cores from 14 different lakes in New Zealand and China ranging from oligotrophic to highly eutrophic and shallow to deep, and found that the shape of vertical profiles of total P, a key nutrient for lake productivity, can be similar in sediments across gradients of widely differing trophic status. We derived and applied empirical and mechanistic diagenesis steady state profile models to describe the vertical distribution of C, N and P in the sediments. These models, which focus on large scale temporal (decades) and spatial (up to 35 cm in the vertical) processes, revealed that density-differentiated burial and biodiffusive mixing, were strongly correlated with vertical concentration gradients of sediment C, N and P content, whereas lake trophic status was not. A sensitivity analysis of parameters included in the diagenetic model further showed that the processes including flux of organic matter to the sediment-water interface, burial (net sedimentation), breakdown of organic matter and biodiffusion all significantly can influence the vertical distribution of sediment P content. We conclude that geochemical studies attempting to evaluate drivers of the vertical distribution of sediment C, N, and P content in lake sediments should also account for the natural diagenetic drivers of vertical concentration gradients, assisted with application of similar models to those presented in this study. This would include quantification of key sediment diagenesis model parameters to separate out the influence of anthropogenic activities.

text: Evaluating the influence of lake morphology, trophic status and diagenesis on geochemical profiles in lake sediments Recent geochemical studies provide evidence that changes in vertical distributions of nutrients in lake sediments are driven by anthropogenic activities, based primarily on trends of increasing concentrations in upper sediment layers. However, we show that vertical concentration profiles of carbon (C), nitrogen (N) and phosphorus (P) in lake sediments can be higher in the upper, most recently deposited sediment strata, driven largely by natural diagenetic processes and not eutrophication alone. We examined sediment cores from 14 different lakes in New Zealand and China ranging from oligotrophic to highly eutrophic and shallow to deep, and found that the shape of vertical profiles of total P, a key nutrient for lake productivity, can be similar in sediments across gradients of widely differing trophic status. We derived and applied empirical and mechanistic diagenesis steady state profile models to describe the vertical distribution of C, N and P in the sediments. These models, which focus on large scale temporal (decades) and spatial (up to 35 cm in the vertical) processes, revealed that density-differentiated burial and biodiffusive mixing, were strongly correlated with vertical concentration gradients of sediment C, N and P content, whereas lake trophic status was not. A sensitivity analysis of parameters included in the diagenetic model further showed that the processes including flux of organic matter to the sediment-water interface, burial (net sedimentation), breakdown of organic matter and biodiffusion all significantly can influence the vertical distribution of sediment P content. We conclude that geochemical studies attempting to evaluate drivers of the vertical distribution of sediment C, N, and P content in lake sediments should also account for the natural diagenetic drivers of vertical concentration gradients, assisted with application of similar models to those presented in this study. This would include quantification of key sediment diagenesis model parameters to separate out the influence of anthropogenic activities.

year: 2010

title: A Systematic review: Psychopathy and personality in subclinical populations

authors: Joubert, Kayla

subjects: Psychopathy

abstract: Literature concerning psychopathy has grown since the early 1940s, when it was described as a clinical psychological disorder by Cleckley, 1941. Psychopathy was defined by factors such as callousness, manipulativeness, superficial charm, egocentricity, impulsivity, risk-taking and antisocial behaviour. There has been a longstanding debate concerning the appropriate models and measures related to psychopathy, which encouraged the development of many measures to capture psychopathic personality factors.
Through the development of different measures and in addition to psychopathy’s clinical and criminal form, there have been advancements towards a subclinical form of psychopathy. The subclinical form of psychopathy involves factors which conceptualise psychopathy, however
rather than only existing in a clinical or criminal population, they also exist in subclinical populations. Subclinical populations are portrayed as the range of normal personalities in general populations also defined as noninstitutionalised populations, such as the workplace. In this systematic review, the term subclinical will be referred to as psychopathy in the workplace, due to the variety of definitions which exist, of the word ‘subclinical’.
In addition to the development of clinical and criminal measures of psychopathy, recent research has emerged in literature, prompting interest in subclinical psychopathy and its relationship with the Five-Factor Model of personality (FFM; McCrae & Costa, 1987). The concept of subclinical psychopathy and how it’s measured in subclinical populations using the (FFM) of personality is essential in highlighting the potential outcomes that occur at an interpersonal and organisational level (subclinical) when considering the workplace.
In exploring existing literature concerning psychopathy and personality as the Five-Factor Model (FFM), the current systematic review aims to investigate the relationship between clinical or criminal psychopathy and subclinical psychopathy, and how subclinical psychopathy is measured. An extensive systematic review was implemented using 7 databases and three key features; psychopathy, personality (FFM) and the workplace. After removing 7149 duplicates and studies which were deemed ineligible, 418 studies were appraised as being relevant to the inclusion and exclusion criteria with only 5 studies examining the relationship between psychopathy and personality, (FFM) and how psychopathy is measured in subclinical settings, such as the workplace.
These findings suggest future research should aim to develop a measure of subclinical psychopathy through the use of the FFM, to detect psychopathic factors in subclinical populations. The FFM is used within subclinical populations such as the workplace, measuring personality successfully through five factors; openness, conscientiousness, extraversion, agreeableness and neuroticism. The FFM factors overlap with constructs of clinical psychopathy, and therefore, could be used to measure subclinical psychopathic personality factors in subclinical populations.

text: A Systematic review: Psychopathy and personality in subclinical populations Literature concerning psychopathy has grown since the early 1940s, when it was described as a clinical psychological disorder by Cleckley, 1941. Psychopathy was defined by factors such as callousness, manipulativeness, superficial charm, egocentricity, impulsivity, risk-taking and antisocial behaviour. There has been a longstanding debate concerning the appropriate models and measures related to psychopathy, which encouraged the development of many measures to capture psychopathic personality factors.
Through the development of different measures and in addition to psychopathy’s clinical and criminal form, there have been advancements towards a subclinical form of psychopathy. The subclinical form of psychopathy involves factors which conceptualise psychopathy, however
rather than only existing in a clinical or criminal population, they also exist in subclinical populations. Subclinical populations are portrayed as the range of normal personalities in general populations also defined as noninstitutionalised populations, such as the workplace. In this systematic review, the term subclinical will be referred to as psychopathy in the workplace, due to the variety of definitions which exist, of the word ‘subclinical’.
In addition to the development of clinical and criminal measures of psychopathy, recent research has emerged in literature, prompting interest in subclinical psychopathy and its relationship with the Five-Factor Model of personality (FFM; McCrae & Costa, 1987). The concept of subclinical psychopathy and how it’s measured in subclinical populations using the (FFM) of personality is essential in highlighting the potential outcomes that occur at an interpersonal and organisational level (subclinical) when considering the workplace.
In exploring existing literature concerning psychopathy and personality as the Five-Factor Model (FFM), the current systematic review aims to investigate the relationship between clinical or criminal psychopathy and subclinical psychopathy, and how subclinical psychopathy is measured. An extensive systematic review was implemented using 7 databases and three key features; psychopathy, personality (FFM) and the workplace. After removing 7149 duplicates and studies which were deemed ineligible, 418 studies were appraised as being relevant to the inclusion and exclusion criteria with only 5 studies examining the relationship between psychopathy and personality, (FFM) and how psychopathy is measured in subclinical settings, such as the workplace.
These findings suggest future research should aim to develop a measure of subclinical psychopathy through the use of the FFM, to detect psychopathic factors in subclinical populations. The FFM is used within subclinical populations such as the workplace, measuring personality successfully through five factors; openness, conscientiousness, extraversion, agreeableness and neuroticism. The FFM factors overlap with constructs of clinical psychopathy, and therefore, could be used to measure subclinical psychopathic personality factors in subclinical populations.

year: 2022

title: Waitangi Soda Springs alum dosing – Bioavailability of aluminium 2011-2020

authors: Ling, Nicholas

abstract: Continuous alum dosing of the Waitangi Soda Springs at Lake Rotoehu commenced in 2011 to reduce inflows of dissolved reactive phosphorus to Lake Rotoehu. Analyses of bioaccumulation in the tissues of kōura and goldfish from Lake Rotoehu were undertaken on animals collected annually since 2013 to determine the bioavailability and bioaccumulation of aluminium. Lake Rotoehu kōura and goldfish collected in 2013 showed slightly elevated aluminium concentrations in the gills indicating enhanced exposure to aluminium but little evidence for significant bioaccumulation in tissues. Concentrations in goldfish liver and gills were highest in 2016, but not significantly different to goldfish collected from Lake Rotorua in 2013 and flesh concentrations were low. Analyses of animals collected in 2020 confirm these earlier findings with no evidence of enhanced bioaccumulation of aluminium in Lake Rotoehu biota.

text: Waitangi Soda Springs alum dosing – Bioavailability of aluminium 2011-2020 Continuous alum dosing of the Waitangi Soda Springs at Lake Rotoehu commenced in 2011 to reduce inflows of dissolved reactive phosphorus to Lake Rotoehu. Analyses of bioaccumulation in the tissues of kōura and goldfish from Lake Rotoehu were undertaken on animals collected annually since 2013 to determine the bioavailability and bioaccumulation of aluminium. Lake Rotoehu kōura and goldfish collected in 2013 showed slightly elevated aluminium concentrations in the gills indicating enhanced exposure to aluminium but little evidence for significant bioaccumulation in tissues. Concentrations in goldfish liver and gills were highest in 2016, but not significantly different to goldfish collected from Lake Rotorua in 2013 and flesh concentrations were low. Analyses of animals collected in 2020 confirm these earlier findings with no evidence of enhanced bioaccumulation of aluminium in Lake Rotoehu biota.

year: 2021