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28 result(s) for "Gibb, Stuart W."
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Heat-Stress and Light-Stress Induce Different Cellular Pathologies in the Symbiotic Dinoflagellate during Coral Bleaching
Coral bleaching is a significant contributor to the worldwide degradation of coral reefs and is indicative of the termination of symbiosis between the coral host and its symbiotic algae (dinoflagellate; Symbiodinium sp. complex), usually by expulsion or xenophagy (symbiophagy) of its dinoflagellates. Herein, we provide evidence that during the earliest stages of environmentally induced bleaching, heat stress and light stress generate distinctly different pathomorphological changes in the chloroplasts, while a combined heat- and light-stress exposure induces both pathomorphologies; suggesting that these stressors act on the dinoflagellate by different mechanisms. Within the first 48 hours of a heat stress (32°C) under low-light conditions, heat stress induced decomposition of thylakoid structures before observation of extensive oxidative damage; thus it is the disorganization of the thylakoids that creates the conditions allowing photo-oxidative-stress. Conversely, during the first 48 hours of a light stress (2007 µmoles m(-2) s(-1) PAR) at 25°C, condensation or fusion of multiple thylakoid lamellae occurred coincidently with levels of oxidative damage products, implying that photo-oxidative stress causes the structural membrane damage within the chloroplasts. Exposure to combined heat- and light-stresses induced both pathomorphologies, confirming that these stressors acted on the dinoflagellate via different mechanisms. Within 72 hours of exposure to heat and/or light stresses, homeostatic processes (e.g., heat-shock protein and anti-oxidant enzyme response) were evident in the remaining intact dinoflagellates, regardless of the initiating stressor. Understanding the sequence of events during bleaching when triggered by different environmental stressors is important for predicting both severity and consequences of coral bleaching.
Review of Glyphosate-Based Herbicide and Aminomethylphosphonic Acid (AMPA): Environmental and Health Impacts
The use of synthetic molecules to achieve specific goals is steadily increasing in the environment, and these molecules adversely impact human health and ecosystem services. Considering the adverse effects, a better understanding of how these molecules behave in the environment and their associated risks is necessary to keep their use acceptably limited. To meet the demands of farmers and combat weed problems, woodlands and farmlands are sprayed with agrochemicals, primarily glyphosate-based herbicides. Farmers increasingly embrace these herbicides containing glyphosate. Glyphosate and aminomethylphosphonic acid (AMPA), a key metabolite of glyphosate, have been reported as toxicological concerns when they become more prevalent in the food chain. The chemical glyphosate has been linked to various health issues in humans and other living organisms, including endocrine disruption, reproductive issues, tumours, non-Hodgkin lymphomas, and liver, heart, and blood problems. Therefore, the current review aims to compile data on glyphosate-based herbicide use in the environment, potential risks to human and ecological health, and various maximum residual limits for crops as suggested by international organizations. As a result, regulatory agencies can advise glyphosate users on safe usage practices and synthesize herbicides more efficiently.
Prevalence of Liver Fluke (Fasciola hepatica) in Wild Red Deer (Cervus elaphus): Coproantigen ELISA Is a Practicable Alternative to Faecal Egg Counting for Surveillance in Remote Populations
Red deer (Cervus elaphus) are hosts of liver fluke (Fasciola hepatica); yet, prevalence is rarely quantified in wild populations. Testing fresh samples from remote regions by faecal examination (FE) can be logistically challenging; hence, we appraise frozen storage and the use of a coproantigen ELISA (cELISA) for F. hepatica surveillance. We also present cELISA surveillance data for red deer from the Highlands of Scotland. Diagnoses in faecal samples (207 frozen, 146 fresh) were compared using a cELISA and by FE. For each storage method (frozen or fresh), agreement between the two diagnostics was estimated at individual and population levels, where population prevalence was stratified into cohorts (e.g., by sampling location). To approximate sensitivity and specificity, 65 post-slaughter whole liver examinations were used as a reference. At the individual level, FE and cELISA diagnoses agreed moderately (κfrozen = 0.46; κfresh = 0.51), a likely reflection of their underlying principles. At the population level, FE and cELISA cohort prevalence correlated strongly (Pearson's R = 0.89, p < 0.0001), reflecting good agreement on relative differences between cohort prevalence. In frozen samples, prevalence by cELISA exceeded FE overall (42.8% vs. 25.8%) and in 9/12 cohorts, alluding to differences in sensitivity; though, in fresh samples, no significant difference was found. In 959 deer tested by cELISA across the Scottish Highlands, infection prevalence ranged from 9.6% to 53% by sampling location. We highlight two key advantages of cELISA over FE: i) the ability to store samples long term (frozen) without apparent loss in diagnostic power; and ii) reduced labour and the ability to process large batches. Further evaluation of cELISA sensitivity in red deer, where a range of fluke burdens can be obtained, is desirable. In the interim, the cELISA is a practicable diagnostic for F. hepatica surveillance in red deer, and its application here has revealed considerable geographic, temporal, sex and age related differences in F. hepatica prevalence in wild Scottish Highland red deer.
Source Apportionment and Risk Assessment of Emerging Contaminants: An Approach of Pharmaco-Signature in Water Systems
This paper presents a methodology based on multivariate data analysis for characterizing potential source contributions of emerging contaminants (ECs) detected in 26 river water samples across multi-scape regions during dry and wet seasons. Based on this methodology, we unveil an approach toward potential source contributions of ECs, a concept we refer to as the \"Pharmaco-signature.\" Exploratory analysis of data points has been carried out by unsupervised pattern recognition (hierarchical cluster analysis, HCA) and receptor model (principal component analysis-multiple linear regression, PCA-MLR) in an attempt to demonstrate significant source contributions of ECs in different land-use zone. Robust cluster solutions grouped the database according to different EC profiles. PCA-MLR identified that 58.9% of the mean summed ECs were contributed by domestic impact, 9.7% by antibiotics application, and 31.4% by drug abuse. Diclofenac, ibuprofen, codeine, ampicillin, tetracycline, and erythromycin-H2O have significant pollution risk quotients (RQ>1), indicating potentially high risk to aquatic organisms in Taiwan.
Introduction of human pharmaceuticals from wastewater treatment plants into the aquatic environment: a rural perspective
Incomplete removal of pharmaceuticals during wastewater treatment can result in their discharge into the aquatic environment. The discharge of pharmaceuticals in wastewater treatment plant (WWTP) effluents into rivers, lakes and the oceans has led to detectable concentrations of pharmaceuticals in the aquatic environment in many countries. However, to date studies of WWTP discharges into the aquatic environment have largely been confined to areas of relatively high population density, industrial activity or systems impacted on by such areas. In this work, two sites in the far north of Scotland were used to assess whether, and which, pharmaceuticals were being introduced into natural waters in a rural environment with low population density. Samples from two WWTPs (with differing modes of operation), and one receiving water, the River Thurso, were analysed for the presence of 12 pharmaceuticals (diclofenac, clofibric acid, erythromycin, ibuprofen, mefenamic acid, paracetamol, propranolol, sulfamethoxazole, tamoxifen, trimethoprim and dextropropoxyphene). Ten of the 12 pharmaceuticals investigated were detected in at least one of the 40 WWTP effluent samples. Maximum concentrations ranged from 7 ng L −1 (sulfamethoxazole) to 22.8 μg L −1 (paracetamol) with diclofenac and mefenamic acid being present in all of samples analysed at concentrations between 24.2 and 927 ng L −1 and 11.5 and 22.8 μg L −1 , respectively. Additionally, the presence of four pharmaceuticals at ng L −1 levels in the River Thurso, into which one of the WWTPs discharges, shows that such discharges result in measurable levels of pharmaceuticals in the environment. This provides direct evidence that, even in rural areas with low population densities, effluents from WWTPs can produce quantifiable levels of human pharmaceutical in the natural aquatic environment. These observations indicate that human pharmaceuticals may be considered as contaminants, with potential to influence water quality, management and conservation not only in urban and industrial regions but also those more rural in nature.
Synthesis optimisation and characterisation of chitosan-calcite adsorbent from fishery-food waste for phosphorus removal
Here, Box-Behnken design (BBD) approaches were utilised to optimise synthesis methodology for the chitosan-calcite rich adsorbent (CCM) made from fishery-food waste material (crab carapace), using low-temperature activation and potassium hydroxide (KOH). The effect of activation temperature, activation time and impregnation ratio was studied. The final adsorbent material was evaluated for its phosphorus (P) removal efficiency from liquid phase. Results showed that impregnation ratio was the most significant individual factor as this acted to increase surface deacetylation of the chitin (to chitosan) and increased the number of amine groups (–NH 2 ) in the chitosan chain. P removal efficiency approached 75.89% (at initial P concentration of 20 mg/L) under optimised experimental conditions, i.e. where the impregnation ratio for KOH:carapace (g/g) was 1:1, the activation temperature was 105 °C and the activation time was 150 min. Predicted responses were in good agreement with the experimental data. Additionally, the pristine and CCM material were further analysed using scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX), Brunauer-Emmett-Teller technique (BET), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and thermal gravimetric analysis (TGA). Characterisation showed enhancements in surface chemistry (introducing positively charged amine groups), textural properties and thermal stability of the CCM.
A Compilation of Global Bio-Optical in Situ Data for Ocean-Colour Satellite Applications – Version Two
A global compilation of in situ data is useful to evaluate the quality of ocean-colour satellite data records. Here we describe the data compiled for the validation of the ocean-colour products from the ESA Ocean Colour Climate Change Initiative (OC-CCI). The data were acquired from several sources (including, inter alia, MOBY, BOUSSOLE, AERONETOC, SeaBASS, NOMAD, MERMAID, AMT, ICES, HOT, GeP&CO) and span the period from 1997 to 2018. Observations of the following variables were compiled: spectral remote-sensing reflectances, concentrations of chlorophyll-a, spectral inherent optical properties, spectral diffuse attenuation coefficients and total suspended matter. The data were from multi-project archives acquired via open internet services or from individual projects, acquired directly from data providers. Methodologies were implemented for homogenisation, quality control and merging of all data. No changes were made to the original data, other than averaging of observations that were close in time and space, elimination of some points after quality control and conversion to a standard format. The final result is a merged table designed for validation of satellite-derived ocean-colour products and available in text format. Metadata of each in situ measurement (original source, cruise or experiment, principal investigator) were propagated throughout the work and made available in the final table. By making the metadata available, provenance is better documented, and it is also possible to analyse each set of data separately. This paper also describes the changes that were made to the compilation in relation to the previous version (Valente et al., 2016). The compiled data are available at https://doi.org/10.1594/PANGAEA.898188.
A Compilation of Global Bio-Optical in Situ Data for Ocean-Colour Satellite Applications
A compiled set of in situ data is important to evaluate the quality of ocean-colour satellite-data records. Here we describe the data compiled for the validation of the ocean-colour products from the ESA Ocean Colour Climate Change Initiative (OC-CCI). The data were acquired from several sources (MOBY, BOUSSOLE, AERONET-OC, SeaBASS, NOMAD, MERMAID, AMT, ICES, HOT, GePCO), span between 1997 and 2012, and have a global distribution. Observations of the following variables were compiled: spectral remote-sensing reflectances, concentrations of chlorophyll a, spectral inherent optical properties and spectral diffuse attenuation coefficients. The data were from multi-project archives acquired via the open internet services or from individual projects, acquired directly from data providers. Methodologies were implemented for homogenisation, quality control and merging of all data. No changes were made to the original data, other than averaging of observations that were close in time and space, elimination of some points after quality control and conversion to a standard format. The final result is a merged table designed for validation of satellite-derived ocean-colour products and available in text format. Metadata of each in situ measurement (original source, cruise or experiment, principal investigator) were preserved throughout the work and made available in the final table. Using all the data in a validation exercise increases the number of matchups and enhances the representativeness of different marine regimes. By making available the metadata, it is also possible to analyse each set of data separately. The compiled data are available at doi:10.1594PANGAEA.854832 (Valente et al., 2015).
Sensitivity of Ferry Services to the Western Isles of Scotland to Changes in Wave and Wind Climate
The roughness of the seas is rarely mentioned as a major factor in the economic or social welfare of a region. In this study, the relationship between the ocean wave climate and the economy of the Western Isles of Scotland is examined. This sparsely populated region has a high dependency on marine activities, and ferry services provide vital links between communities. The seas in the region are among the roughest in the world during autumn and winter, however, making maintenance of a reliable ferry service both difficult and expensive. A deterioration in wave and wind climate either in response to natural variability or as a regional response to anthropogenic climate change is possible. Satellite altimetry and gale-frequency data are used to analyze the contemporary response of wave and wind climate to the North Atlantic Oscillation (NAO). The sensitivity of wave climate to the NAO extends to ferry routes that are only partially sheltered and are exposed to ocean waves; thus, the reliability of ferry services is sensitive to NAO. Any deterioration of the wave climate will result in a disproportionately large increase in ferry-service disruption. The impacts associated with an unusually large storm event that affected the region in January 2005 are briefly explored to provide an insight into vulnerability to future storm events.
Molecular Evidence of Cryptic Speciation in Planktonic Foraminifers and Their Relation to Oceanic Provinces
The fossil record of planktonic foraminifers is a key source of data on the biodiversity and evolution of marine plankton. One of the most distinctive foraminiferal taxa, Orbulina universa, widely used as a stratigraphic and paleoclimatic index, has always been regarded as a single species. Here we present a phylogenetic analysis of Orbulina small subunit rDNA sequences from 25 pelagic stations covering 100 degrees latitude in the Atlantic Ocean. The genetic data reveal the presence of three cryptic species, whose distribution is clearly correlated to hydrographic provinces, and particularly to sea-surface total chlorophyll a concentration. Our results, together with previous studies, suggest that a considerable part of the diversity among planktonic foraminifers has been overlooked in morphological taxonomies. Our data also support the idea that planktonic foraminifers, even if adapted to particular hydrographic conditions, are high-dispersal organisms whose speciation may be similar to that of other high-dispersal taxa in which reproductive mechanisms and behavior, rather than just geographic barriers to dispersal, play key roles in species formation and maintenance.