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"Oliver, Ian"
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Ecotoxicological assessments of biochar additions to soil employing earthworm species Eisenia fetida and Lumbricus terrestris
by
Oliver, Ian W.
,
Elliston, Tom
in
Animals
,
Aquatic Pollution
,
Atmospheric Protection/Air Quality Control/Air Pollution
2020
Biochar is the degradation-resistant product generated by the pyrolysis of organic materials and is produced for the intended use of land application in order to promote carbon sequestration and soil improvement. However, despite the many potential benefits biochar application offers, it is important to quantify any ecological impacts that may result from soil amendment in order to avoid potentially causing negative effects upon soil biota which are crucial in the many ecosystem services provided by soil. Any impacts on earthworms in particular are important to evaluate because of their pivotal role in organic matter breakdown, nutrient cycling and soil formation. In this study, we conducted a series of ecotoxicological assays to determine lethal and sublethal (avoidance, mass change and moisture content) effects of heavy biochar applications that reflect levels that may be used in soil restoration efforts. Two earthworm species,
Eisenia fetida
, an epigeic species, and
Lumbricus terrestris
, an anecic species, were utilised as test organisms. Two types of biochar, produced from wheat straw and rice husk feedstocks, respectively, were applied to OECD artificial soil and to a natural soil (Kettering loam) at rates of up to 20%
w
/
w
. The influence of biochar application on soil porewater chloride, fluoride and phosphate concentrations was also assessed. The biochar applications induced only a subtle level of avoidance behaviour while effects on survival over a 4-week exposure period were inconsistent. However, death and physical damage to some individual earthworms at high biochar application rates were observed, the mechanisms and processes leading to which should be investigated further. Earthworm development (mean mass change over time) proved to be a more sensitive measure, revealing negative effects on
L. terrestris
at 10% and 20% (
w
/
w
) wheat biochar applications in OECD soil and at 20% (
w
/
w
) applications of both biochars in Kettering loam. The moisture content of
E. fetida
remained remarkably consistent across all treatments (~ 82%), indicating that this is not a sensitive measure of effects. The high rates of biochar application resulted in increased chloride (2 to 3-fold) and phosphate (100-fold) concentrations in simulated soil porewaters, which has important implications for soil fertility and production but also for environmental management.
Journal Article
A Security Framework for Increasing Data and Device Integrity in Internet of Things Systems
2023
The trustworthiness of a system is not just about proving the identity or integrity of the hardware but also extends to the data, control, and management planes of communication between devices and the software they are running. This trust in data and device integrity is desirable for Internet of Things (IoT) systems, especially in critical environments. In this study, we developed a security framework, IoTAttest, for building IoT systems that leverage the Trusted Platform Module 2.0 and remote attestation technologies to enable the establishment of IoT devices’ collected data and control plan traffic integrity. After presenting the features and reference architecture of IoTAttest, we evaluated the privacy preservation and validity through the implementation of two proof-of-concept IoT applications that were designed by two teams of university students based on the reference architecture. After the development, the developers answered open questions regarding their experience and perceptions of the framework’s usability, limitations, scalability, extensibility, potential, and security. The results indicate that IoTAttest can be used to develop IoT systems with effective attestation to achieve device and data integrity. The proof-of-concept solutions’ outcomes illustrate the functionalities and performance of the IoT framework. The feedback from the proof-of-concept developers affirms that they perceived the framework as usable, scalable, extensible, and secure.
Journal Article
Microbial genome (Illumina MiSeq) sequencing of drinking water treatment residuals to evaluate compatibility with environmental applications
2023
The clarification of drinking water leads to the production of large quantities of water treatment residuals (WTRs). DNA was extracted from six WTR samples collected from water treatment plants within the UK to compare their bacterial communities and examine whether factors such as coagulant usage (aluminium versus iron salt), the type of water source (reservoir or river), or leachable chemical composition influence these communities. Bacterial 16S variable region 4 (V4) was amplified and sequenced using Illumina MiSeq sequencing. The most abundant phyla in WTR samples were
Proteobacteria
,
Actinobacteria
,
Bacteroidetes
,
Acidobacteria
, and
Firmicutes
, collectively representing 92.77–97.8% of the total bacterial sequences. Statistical analysis of microbial profiles indicated that water source played a significant role in microbial community structure, diversity, and richness, however coagulant type did not. PERMANOVA analysis showed that no single chemical variable (pH, organic matter, or extractable element concentration) influenced microbial composition significantly; however, canonical correspondence analysis of WTR microbiomes yielded a model using all these variables that could be used to explain variations in microbial community structures of WTRs (
p
< 0.05). No common, potentially toxic cyanobacteria, or related pathogens of concern were found. Analysis with PICRUSt showed that WTRs all had similar predicted microbial functional profiles. Overall, the results indicate that WTRs analysed in this study are unlikely to pose any threat to soil microbial community structure when applied to land as a soil conditioner or enhancer and may help to enhance the soil microbial community.
Journal Article
Expert predictions of changes in vegetation condition reveal perceived risks in biodiversity offsetting
by
Dorrough, Josh
,
Sinclair, Steve J.
,
Oliver, Ian
in
Analysis
,
Biodiversity
,
Biodiversity conservation
2019
Biodiversity offsetting typically involves the trade of certain losses of habitat with uncertain future conservation benefits. Predicting the latter requires estimates of two outcomes; the biodiversity losses without conservation management (averted loss), and the biodiversity gains with conservation management (management gain). However, because empirical data to inform these estimates are limited, they are normally guided by expert opinion, often derived via unstructured methods without consideration of uncertainty. Here we used a structured elicitation with 29 experts to gather estimates of averted loss and management gain at offset sites. We used two methods; (i) experts estimated change in an aggregate biodiversity value (vegetation condition) and; (ii) experts provided probabilistic estimates of change for individual vegetation condition attributes, such as the richness and cover of plant growth forms. On average, experts predicted there would be only modest improvements with conservation management, yet uncertainty and variation among experts was large; in some cases, conservation benefits were not predicted. Estimates of change in vegetation condition suggested that benefits were from both averted loss and management gains and were thought to most likely arise in cases where starting condition was low to moderate. Similar patterns were observed for individual vegetation condition attributes, with management gains, relative to a reference, tending to be negatively correlated with starting value. Our study finds that: (i) on average, gains at offset sites are expected to be small, (ii) at many sites, experts do not believe gains can be obtained, and (iii) experts' opinions can be divergent resulting in elevated levels of uncertainty. The potential for losses under conservation management highlights the need to: identify those components of biodiversity most likely to benefit from conservation management; better understand those situations when offset obligations are most likely to be met and conversely those situations with higher risk; and further develop offset mechanisms that encourage early or prior gains. These findings together with the global proliferation of biodiversity offsetting, provide a strong imperative to improve empirical data and investment in long-term, site-based monitoring of biodiversity outcomes at offset sites.
Journal Article
Additive and synergistic effects of land cover, land use and climate on insect biodiversity
by
Dorrough, Josh
,
Doherty, Helen
,
Andrew, Nigel R.
in
Australia
,
Biodiversity
,
Biomedical and Life Sciences
2016
Context
We address the issue of adapting landscapes for improved insect biodiversity conservation in a changing climate by assessing the importance of additive (main) and synergistic (interaction) effects of land cover and land use with climate.
Objectives
We test the hypotheses that ant richness (species and genus), abundance and diversity would vary according to land cover and land use intensity but that these effects would vary according to climate.
Methods
We used a 1000 m elevation gradient in eastern Australia (as a proxy for a climate gradient) and sampled ant biodiversity along this gradient from sites with variable land cover and land use.
Results
Main effects revealed: higher ant richness (species and genus) and diversity with greater native woody plant canopy cover; and lower species richness with higher cultivation and grazing intensity, bare ground and exotic plant groundcover. Interaction effects revealed: both the positive effects of native plant canopy cover on ant species richness and abundance, and the negative effects of exotic plant groundcover on species richness were greatest at sites with warmer and drier climates.
Conclusions
Impacts of climate change on insect biodiversity may be mitigated to some degree through landscape adaptation by increasing woody native vegetation cover and by reducing land use intensity, the cover of exotic vegetation and of bare ground. Evidence of synergistic effects suggests that landscape adaptation may be most effective in areas which are currently warmer and drier, or are projected to become so as a result of climate change.
Journal Article
Portable X-ray fluorescence (pXRF) analysis of heavy metal contamination in church graveyards with contrasting soil types
by
Madden, Charles
,
Oliver, Ian W.
,
Wisniewski, Kristopher D.
in
Alzheimer's disease
,
Anomalies
,
Aquatic Pollution
2022
Human remains have been interred in burial grounds since historic times. Although the re-use of graveyards differs from one country, region or time period to another, over time, graveyard soil may become contaminated or enriched with heavy metal elements. This paper presents heavy metal element soil analysis from two UK church graveyard study sites with contrasting necrosols, but similar burial densities and known burial ages dating back to the sixteenth century and some possibly older than 1,000 years. Portable X-ray fluorescence element laboratory-based analyses were undertaken on surface and near-surface soil pellets. Results show elevated levels of Fe, Pb, Mn, Cr, Cu, Zn and Ca in both necrosols when compared with background values. Element concentration anomalies remained consistently higher than background samples down to 2 m, but reduced with distance away from church buildings. Element concentration anomalies are higher in the clay-rich necrosol than in sandy necrosol. Study result implications suggest that long-used necrosols are likely to be more contaminated with heavy metal elements than similar soil outside graveyards with implications for burial grounds management, adjacent populations and where burial grounds have been deconsecrated and turned to residential dwellings.
Journal Article
Nicotinamide Adenine Dinucleotide Phosphate Oxidases in Glucose Homeostasis and Diabetes-Related Endothelial Cell Dysfunction
by
Brown, Oliver Ian
,
Bridge, Katherine Isabella
,
Kearney, Mark Thomas
in
Animals
,
Biomarkers - blood
,
Blood Glucose - metabolism
2021
Oxidative stress within the vascular endothelium, due to excess generation of reactive oxygen species (ROS), is thought to be fundamental to the initiation and progression of the cardiovascular complications of type 2 diabetes mellitus. The term ROS encompasses a variety of chemical species including superoxide anion (O2•−), hydroxyl radical (OH−) and hydrogen peroxide (H2O2). While constitutive generation of low concentrations of ROS are indispensable for normal cellular function, excess O2•− can result in irreversible tissue damage. Excess ROS generation is catalysed by xanthine oxidase, uncoupled nitric oxide synthases, the mitochondrial electron transport chain and the nicotinamide adenine dinucleotide phosphate (NADPH) oxidases. Amongst enzymatic sources of O2•− the Nox2 isoform of NADPH oxidase is thought to be critical to the oxidative stress found in type 2 diabetes mellitus. In contrast, the transcriptionally regulated Nox4 isoform, which generates H2O2, may fulfil a protective role and contribute to normal glucose homeostasis. This review describes the key roles of Nox2 and Nox4, as well as Nox1 and Nox5, in glucose homeostasis, endothelial function and oxidative stress, with a key focus on how they are regulated in health, and dysregulated in type 2 diabetes mellitus.
Journal Article
Modeling biodiversity benchmarks in variable environments
by
Vesk, Peter A.
,
Watson, Christopher J.
,
Somerville, Michael
in
Australia
,
Bayes Theorem
,
Bayesian analysis
2019
Effective environmental assessment and management requires quantifiable biodiversity targets. Biodiversity benchmarks define these targets by focusing on specific biodiversity metrics, such as species richness. However, setting fixed targets can be challenging because many biodiversity metrics are highly variable, both spatially and temporally. We present a multivariate, hierarchical Bayesian method to estimate biodiversity benchmarks based on the species richness and cover of native terrestrial vegetation growth forms. This approach uses existing data to quantify the empirical distributions of species richness and cover within growth forms, and we use the upper quantiles of these distributions to estimate contemporary, “best-on-offer” biodiversity benchmarks. Importantly, we allow benchmarks to differ among vegetation types, regions, and seasons, and with changes in recent rainfall. We apply our method to data collected over 30 yr at ∼35,000 floristic plots in southeastern Australia. Our estimated benchmarks were broadly consistent with existing expert-elicited benchmarks, available for a small subset of vegetation types. However, in comparison with expert-elicited benchmarks, our data-driven approach is transparent, repeatable, and updatable; accommodates important spatial and temporal variation; aligns modeled benchmarks directly with field data and the concept of best-on-offer benchmarks; and, where many benchmarks are required, is likely to be more efficient. Our approach is general and could be used broadly to estimate biodiversity targets from existing data in highly variable environments, which is especially relevant given rapid changes in global environmental conditions.
Journal Article
How variation among field assessments can affect biodiversity offset outcomes
by
Caves, Karen
,
Dorrough, Josh W.
,
Gorrod, Emma
in
Assessments
,
Biodiversity
,
Biodiversity loss
2025
Biodiversity offsetting aims to balance biodiversity loss at development sites with gains at offset sites. Measurement of loss and gain relies on transparent and repeatable estimates of biodiversity values. However, these estimates are often derived from field assessments by people who differ in their interpretation and measurement of biodiversity, either randomly or systematically. Variation among people during field assessments may therefore impact offset outcomes and contribute to uncertainty around the effectiveness of biodiversity offset schemes. Here, we describe variation in loss, gain, and offset outcomes using concurrent assessments by five assessors on eight sites using a multi‐metric biodiversity valuation method from New South Wales, Australia. We found variation among assessors was high for field estimates but substantially decreased for current biodiversity valuations. However, variation increased for the prediction of future biodiversity gains, in the calculation of the required offset area, and contributed an average of 19% variation in development credits (biodiversity loss) and 34% variation in offset credits (biodiversity gain). Evidence of systematic bias among observers for some attributes added further uncertainty to offset outcomes. Our study reveals the need for improved assessor training and field methods to improve assessment consistency, transparency, and reduce offset outcome variability. We used concurrent assessments from five offsets assessors to quantify inter‐observer variation and its effect on biodiversity offset outcomes. Variation among assessors was high during field estimates of biodiversity surrogate values, and this led to uncertain offset outcomes. Global offset schemes will need to reassess their measurement methodology, definitions, and training to improve biodiversity outcomes.
Journal Article
Spatial scaling of microbial eukaryote diversity
by
Gillings, Michael
,
Holmes, Andrew J.
,
Briscoe, David
in
Animal, plant and microbial ecology
,
Aquatic habitats
,
Ascomycota - classification
2004
Patterns in the spatial distribution of organisms provide important information about mechanisms that regulate the diversity of life and the complexity of ecosystems
1
,
2
. Although microorganisms may comprise much of the Earth's biodiversity
3
,
4
and have critical roles in biogeochemistry and ecosystem functioning
5
,
6
,
7
, little is known about their spatial diversification. Here we present quantitative estimates of microbial community turnover at local and regional scales using the largest spatially explicit microbial diversity data set available (> 10
6
sample pairs). Turnover rates were small across large geographical distances, of similar magnitude when measured within distinct habitats, and did not increase going from one vegetation type to another. The taxa–area relationship of these terrestrial microbial eukaryotes was relatively flat (slope
z
= 0.074) and consistent with those reported in aquatic habitats
8
,
9
. This suggests that despite high local diversity, microorganisms may have only moderate regional diversity. We show how turnover patterns can be used to project taxa–area relationships up to whole continents. Taxa dissimilarities across continents and between them would strengthen these projections. Such data do not yet exist, but would be feasible to collect.
Journal Article