A multi-disciplinary study of sediment core records from the Mingulay Reef Complex, a cold-water coral reefs system off western Scotland, highlights the potential of cold-water corals from which detailed centennial-scale palaeo-environmental reconstructions can be derived. This study provides a new insight on the mechanisms controlling Lophelia pertusa reef build-up, shifts in biodiversity, the physical/chemical/biological processes and the sedimentary regime. A detailed record of Mingulay Complex growth history shows unprecedented high average accumulation rates of 3 – 4 mm a-1. Marine radiocarbon reconstruction derived from paired 14C and U-series dated fossil corals revealed substantial abrupt oceanic shifts during the Holocene that have repetitively affected cold-water coral growth, eventually causing local disappearance. These periods of reduced accumulation rates are synchronous with other coral structures from the NE Atlantic illustrating basin wide events. Finally, trace/minor element ratios reproducibility within coral skeleton was investigated to test if palaeo-environmental reconstructions could be made from cold-water corals.

The Lower Parmeener Supergroup consists of 500 to 900 metres of marine and terrigenous sedimentary rocks, deposited in the high-latitude Tasmania Basin during the late Carboniferous to middle Permian, at the end of the late Paleozoic ice age. Two bioclastic carbonate units, the Darlington and Berriedale limestones, are of particular interest due to their formation in this polar, cold-water environment. Both limestones contain ice-rafted debris scattered throughout, signifying numerous icebergs, and are under- and over-lain by glendonitic siltstone indicating near-freezing seawater. Despite the unusual environment, seawater in the Permian Tasmania Basin was, with the exception of an anomalously high 13C value, isotopically and chemically similar to modern seawater. These limestones consist of a high-abundance, low-diversity heterozoan assemblage, dominated by large, robust brachiopods, bryozoans, and Eurydesma bivalves. Sponge spicules and crinoids are locally important constituents. The carbonates are interpreted to have been deposited in mid-shelf environments during sea-level highstands, where the faunal communities were beyond the depths of grounding icebergs, and sufficiently outboard from terrigenous sediment influx and brackish water. Growth and preservation of biogenic carbonates were promoted by up-welling of nutrient-rich water, which sustained high levels of primary productivity in the water column and phosphate concentrations in the sediment. Lower Parmeener Supergroup carbonates were exposed to a complex series of diagenetic processes, commencing on the seafloor and continuing during rapid burial. Limestone composition was further modified by diagenetic fluids associated with the intrusion of Mesozoic igneous rocks. Alteration in the marine paleoenvironment was both destructive and constructive; although dissolution took place there was also coeval precipitation of fibrous calcite cement, phosphate, and glauconite. These processes are interpreted to have been promoted by mixing of marine waters and enabled by microbial degradation of organic matter. In contrast, meteoric diagenesis was insignificant, being confined to minor dissolution and localized cementation, although mechanical compaction was ubiquitous. Chemical compaction was instigated at burial to depths of approximately 150 m, and promoted extensive precipitation of ferroan calcite. Diagenesis may well have ended here, except for the subsequent intrusion of massive Mesozoic diabases and associated injection of silicifying fluids into the limestones. Finally, fractures associated with Cretaceous uplift were filled with late-stage non-ferroan calcite cement. / Thesis (Ph.D, Geological Sciences & Geological Engineering) -- Queen's University, 2008-04-23 11:12:58.461 / NSERC

This thesis explores some important practical considerations concerning the use of species distribution models in marine conservation planning. Using geo-referenced gorgonian distribution data, together with explanatory environmental variables, predictive models have been used to map the spatial distribution of suitable gorgonian (sea fan) habitat in two study sites; Hatton Bank, in the Northeast Atlantic, and Lyme Bay on the south coast of Devon. Generalized Linear Models (GLMs), Generalized Additive Models (GAMs) and a Maximum Entropy (Maxent) model have been used to support critical investigation into important model considerations that have received inadequate attention in the marine environment. The influence of environmental data resolution on model performance has been explored with specific reference to available datasets in the nearshore and offshore environments. The transferability of deep-sea models has been similarly appraised, with recommendations as to the appropriate use of transferred models. Investigating these practical issues will allow managers to make informed decisions with respect to the best and most appropriate use of existing data. This study has also used novel approaches and investigated their suitability for marine conservation planning, including the use of model classification error in the spatial prioritisation of monitoring sites, and the adaptation of an existing presence-only modelling method to include absence data. Together, these studies contribute both practical recommendations for marine conservation planning and novel applications within the wider species distribution modelling discipline, and consider the implications of these developments for managers, to ensure the ongoing improvement and development of models to support conservation planning.

No description available.

Buoyant plumes in cold fresh water are of interest because of the possibility of buoyancy reversal due to the nonlinear relation between temperature and density in water. Thus an initially rising plume may become a fountain. This project aims to mathematically model such plumes and fountains using numerical simulation by the means of a commercial software, Comsol Multiphysics. Both turbulent and lam- inar cases were investigated in different geometries, and with the assumption that density is a quadratic function of temperature. The turbulent flow cases as con- sidered here in this thesis are relevant to practical applications such as industrial discharge in cold lakes: whereas, the laminar flow case relates to laboratory experi- ments which are typically at scales too small for the flow to be turbulent. Previous investigation on warm discharge placed more attention on the biological implications of the spread along the lake bed, and not interested in analysing the dynamics of such flow, which turns out to be our focus. Furthermore, investigations on buoyant plumes that become negatively buoyant at later time (fountain flow) as considered previously, are based on the assumption that density is a linear function of tem- perature: where entrainment always reduces buoyancy. Whereas, the consideration of the temperature of maximum density is crucial and realistic in many practical situations, especially the power station warm discharge. Mixing is then bound to produce a mixture that is denser than both the discharge and the ambient water if receiving water is less than Tm: where this situation differs from plumes with linear mixing properties. Therefore, our focus is to better fathom the behaviour of warm discharge so as to give a detailed description of the flow, and also to observe buoyancy reversal whenever water that is denser than both the discharge and the receiving water is produced. The simulations were carried out for Prandtl number Pr = 7 & 11.4 and over the ranges of Froude number 0.1 ≤ Fr ≤ 5 and Reynolds numbers 50 ≤ Re ≤ 106, with source temperatures that are assumed to be higher than the temperature of maximum density Tm, and the ambient water below the Tm. Our results show some distinct behaviours from those experimental investigations by Bukreev, who also considered warm discharge where water that has temperature above the temperature Tm is initiated into a medium below Tm. The results here also showed some differences from those investigations with the linear dependence relation assumption.

Objectives: Determine if numbness differs in magnitude and duration between 10-, 15-, and 20-min ice bath immersions, when temperature was held constant. Design: Dependant variables; sensation of pressure (g), perceived pain (cm), and skin temperature (º C). A repeated measures 3 X 19 factorial guided this study. Conditions were 10-, 15-, and 20-min ice bath immersions. Measurement times were before immersion, 1, 3, 5, 7, 9, 10, 11, 13, 15, 17, 19, and 20 min immersion, and 1.5, 3, 5, 7, 9 and 11 min postimmersion. Subjects: Eighteen college-aged volunteers. Measurements: Subjects participated in three ice bath immersions (10, 15, and 20 min). Sensation of pressure was tested over the anterior talofibular ligament prior to immersion, and 1.5, 3, 5, 7, 9, and 11 min postimmersion. Cold induced pain was recorded at baseline (prior to treatment), every 2 min during immersion (beginning with 1 min), immediately following foot removal (10, 15, and 20 min), and directly following each monofilament reading (1.5, 3, 5, 7, 9, and 11 min posttreatment). Water bath and skin temperature were recorded every min (baseline to 11 min postimmersion). ANOVA's and Tukey-Kramer multiple range tests were used to determine significance. Results: Water bath temperature was held constant at 1º C. Loss of sensation was greater following 20 min of immersion than 10 min of immersion at all postimmersion measurement times. The greatest loss of sensation was at 1.5 min following the 20-min immersion. Cold induced pain was greatest, in all conditions, during the first 5 min of immersion. Pain peaked at 1 min of immersion and declined sharply until 9 min after immersion. Postimmersion pain was significantly greater following 20 min of immersion than 10 or 15 min of immersion. Skin temperature did not differ among conditions at baseline or during immersion. Conclusions: Our research supports clinical recommendations of 12-20 min initial immersion during cryokinetics. There was no difference in water or skin temperature between groups; therefore, the increased magnitude and duration of numbness following 20-min immersion was due to the increased length of immersion. Prolonging immersion past the point of perceived numbness may be beneficial.

Conventional drinking water treatment consists of a coagulation, flocculation, gravity separation, filtration and disinfection processes each working individually but also as an interdependent system. One of the main reagents used for drinking water treatment are coagulants that destabilise the suspended particles which results in the formation of flocs. For many years, the coagulant of choice was aluminum sulphate, also know as alum. Alum has slowly been replaced by new coagulants, such as polyalumium sulphates and polyaluminum chlorides, because they yield more consistent plant performance than with alum over the wide temperature range experienced by Canadian treatment plants. Recent research has determined that the alum solubility envelop varied significantly in terms of pH range with temperature, thus cold temperature performance may be improved by adjusting the coagulation pH. Dissolved air flotation (DAF) is now used at some water treatment plants to replace sedimentation because it is much more compact than gravity settling, and it is somewhat better than sedimentation for the removal of algae, organics and operation in cold temperatures. The objective of this thesis is to help operators and managers of drinking water treatment plants incorporating DAF by: a) investigating the cold water turbidity removals of DAF systems using alum, the most economical coagulant; and b) investigating the impact of DAF saturator pressure on the bubble sizes produced and floc removal. This first initiative is based on fairly recent research on the impact of pH on the cold-temperature aluminum solubility. It uses this knowledge about the impact of pH to evaluate DAF treatment of Ottawa River water in cold-water conditions using DAF batch tests. The effect of pH against final turbidity at cold temperatures was first evaluated by increasing the pH of the coagulated water, the higher pH helped attain good turbidity removals. For the coagulant dose tested, good turbidity removals were observed for both warm and cold waters at nearly the same pOH conditions. At room temperature the turbidity removals increase with both increasing flocculation G and flocculation time. While at cold temperatures, when aluminum flocs are known to be much more fragile, the turbidity removals appear to be independent of G and GT. The second initiative studied the relationship between floc size and bubble size in DAF systems by changing the DAF saturator pressure. Increasing the saturator pressure did not significantly decrease the mean bubble size. The flocs attach to bubbles that were significantly larger than the bubbles. The assessment of DAF efficiency based on the unitized effluent floc distribution proved inconclusive, it may be possible that the conditions resulting with the larger mean effluent floc size has a greater removal efficiency since it began with a smaller fraction of small flocs entering the flotation stage.

Rugby has become a popular team sport worldwide with players training harder and competing more frequently, placing a great physiological demand on their bodies. To retain this performance level, players need to recover sufficiently between training and competitions. Two popular recovery techniques used are cold water immersion (CWI) and contrast water therapy (CWT). Despite numerous publications a lack still exists with regard to these specific recovery methods on physical and haematological parameters. Against this background, the main objectives of this study were firstly, to determine the effects of CWI compared to those of passive recovery (PAR) over a 48-hour period on physical and haematological parameters after an intense anaerobic exercise session in a cohort of male university-level rugby players. Secondly, to determine the effects of CWT compared to those of PAR over a 48-hour period on physical and haematological parameters after an intense anaerobic exercise session in a cohort of male university-level rugby players. Twenty-three rugby players of the North-West University participated in the study. The players were randomly assigned to either a control (n = 11; age: 20.1±0.3 y) or experimental (n = 12; age: 19.9±0.3 y) group. Participants reported to the laboratory where base line measurements were taken on certain physical (vertical jump test (VJT) height, VJT peak speed, VJT peak power and grip strength) and haematological (base excess (BEx), blood lactate (BLa-), calcium (Ca+), bicarbonate (HCO3), haemoglobin, haematocrit, pH level, partial oxygen level (PO2), partial carbon dioxide (PCO2), plasma glucose, potassium (K+), saturated oxygen (SO2), sodium (Na+) and total carbon dioxide (TCO2)) components. Thereafter participants were accompanied to the field to complete an intense anaerobic exercise session, followed by a recovery period of either CWI vs. PAR (week 1) or CWT vs. PAR (week 2). The recovery session comprised of either sitting passively in a still area (PAR), or immersion of CWI (8–10°C), or alternating immersions of five cycles between cold (1 min; 8–10°C) and warm water (3min; 40-42°C), totalling 20 minutes. Exactly three minutes, 24 and 48 hours after the recovery intervention all the measurements were re-taken to assess acute and longer-term effects of recovery. Descriptive statistics were followed by a linear mixed model analysis with an autoregressive 1 heterogeneous (AR1-Heterogeneous) structure, and between-group differences were examined using a one-way analysis of variance (ANOVA). Significance was set at p ≤0.05. Effect sizes were calculated to determine practical significance per recovery intervention as well as within groups. CWI indicated better recovery than PAR, with three out of the nine variables (BLa-, Na+ and haemoglobin) returning at 0 h post-recovery, and five (PO2, plasma glucose, VJT height, VJT peak power, VJT peak speed) only at 24 h post-CWI. In contrast, the PAR-group did not demonstrate recovery in any of the variables at 0 h post-PAR. However, an improvement was seen in VJT height across all time points. Four (BLa-, haemoglobin, VJT peak power and VJT peak speed) out of a possible nine variables recovered at 24 h with an additional two (PO2 and grip strength) variables showing recuperation at 48 h. A significant decrease (p ≤0.05) was seen in VJT height, PO2 and Na+ from post-anaerobic to immediately following either CWI or PAR (except for VJT height). Significant increases (p ≤0.05) were observed in VJT height, plasma glucose, and Na+ from 0 h post-recovery to 48 h post-recovery for both CWI and PAR. PO2 also significantly increased (p ≤0.05) from 0 h to 24 and 48 h post-CWI and for the PAR-group at 48 h. CWI tended to have a faster recovery rate than PAR over a 24-h period. The CWT vs. PAR showed the same trend, at 0-hours, six variables (BLa-, haemoglobin, VJT-height, VJT peak-power, VJT peak-speed and grip strength) was restored to base line, whereas plasma glucose recovered at 24-hours post-CWT. In addition, players’ jump and grip strength performance improved from base line. The PAR-group demonstrated recovery at 0 hours in four variables (BLa-, VJT height, VJT peak-speed and grip strength), and two variables (Na+ and haemoglobin) at 24-hours and plasma glucose at 48 hours. A significant decrease (p ≤0.05) was seen in haemoglobin and BLa- from post-anaerobic to either 24 or 48 hours for both groups. A significant increase in plasma glucose and PO2 from 0 to 24 hours was observed in both groups. No significant intergroup change in physical components was noticed. However, intergroup results indicated CWT to be superior to PAR with statistical significance observed in BLa- and grip strength (p ≤0.05) at various time points. The conclusion drawn from the above-mentioned results is that a recovery session comprising either 20-minutes of CWI or CWT may lead to significantly better physical components and restoration of haematological components in university-level rugby players compared to that of passive recovery. However, a detrimental effect was noticed in some components over the recovery period. / MA (Sport Science), North-West University, Potchefstroom Campus, 2015

Rugby union training and match-play are physiologically and psychologically very demanding and the execution of post-exercise recovery techniques in players‟ training regimes are therefore necessary to aid in the physiological and psychological restoration of athletes‟ training and performance abilities. However, despite numerous research findings with regard to the efficiency of especially cold water immersion (CWI), contrast water therapy (CWT) and passive recovery (PAR) on the physiological recovery of athletes post-exercise, only a limited number of researchers have examined the possible benefits of these recovery techniques on the psychological recovery of athletes. Consequently, the objectives of this study were firstly to determine the difference between the acute effects of CWI and PAR on the mood states (anger, confusion, depression, fatigue, tension and vigour) and the energy index of university-level rugby players post-exercise, and secondly to determine the difference between the acute effects of CWT and PAR on the mood states and the energy index of university-level rugby players post-exercise. Twenty-three under/21 university-level rugby players (age 20.1 ± 0.41) of a South African university club voluntarily participated in this study. The players were randomly divided into a control group (PAR) and an experimental group (CWI or CWT). Participants completed the Stellenbosch Mood Scale (STEMS) questionnaire over four time periods: during the morning (baseline); before completion of a high-intensity anaerobic training session (pre-anaerobic); after completion of a high-intensity anaerobic training session of 15 minutes (post-anaerobic) and after completion of a 20-minute recovery session (post-recovery). Blood lactate measurements were also taken 3 minutes after completion of the anaerobic session. To test the first objective, the experimental group completed 20 minutes of CWI, whereas the control group recovered passively for the same time period. For the purpose of the second objective, the experimental group completed 20 minutes of CWT, whereas the control group recovered passively for the same time period. Although the dependent t-test and effect size results of the first study showed that the experimental group (CWI) experienced no significant changes from the pre-anaerobic to post-recovery time periods for any of the STEMS subscale values or the energy index, the control group‟s (PAR) confusion, depression and tension subscale values decreased significantly (p < 0.05) from the pre-anaerobic to the post-recovery time periods. Despite these changes, the one-way between groups‟ analysis of covariance (ANCOVA) revealed no significant differences, except for the vigour subscale, which obtained a medium practical significant increase [Effect size (ES) = 0.65)] for the experimental compared to the control group when the pre-anaerobic and post-recovery changes in the STEMS subscale and energy index values between groups were compared. The dependent t-test and effect size results of the second study indicated that neither the experimental (CWT) nor the control group (PAR) experienced significant changes from pre-anaerobic to post-recovery time periods for any of the STEMS subscale or energy index values. However, the ANCOVA revealed that the experimental group showed a statistically significant higher value for the vigour subscale (p = 0.05) when compared to the control group. In addition, for vigour, the experimental group recorded a large practically significant higher value (ES = 0.92) for vigour as well as a large practically significant lower value for fatigue (ES = 0.88) compared to the control group. To the researchers‟ knowledge, this was the first study to compare the efficacy of CWI, CWT and PAR on the recovery of athletes‟ STEMS-derived mood states. Previous studies mainly focused on perceived fatigue, muscle soreness, Profile of Mood States- (POMS-) derived mood states and rate of perceived exertion (RPE) when investigating psychological recovery in athletes. However, despite the uniqueness of this study, results showed that when compared to PAR, CWI and CWT did not aid more in the acute psychological recovery of university-level rugby players‟ mood states. Vigour was the only mood state subscale for which both the CWI and CWT groups showed a practical or statistically significant higher value compared to the PAR group, while fatigue obtained a higher practical significant value for only CWT when compared to PAR. Therefore, although the study results support the use of CWI and CWT to alleviate vigour and fatigue post-exercise when compared to PAR, further research is required to gain understanding into the psychological mechanisms of both CWT and PAR, with an emphasis on knowledge and information in recovery of mood disturbances after exercise. / MSc (Sport Science), North-West University, Potchefstroom Campus, 2015

Rugby has become a popular team sport worldwide with players training harder and competing more frequently, placing a great physiological demand on their bodies. To retain this performance level, players need to recover sufficiently between training and competitions. Two popular recovery techniques used are cold water immersion (CWI) and contrast water therapy (CWT). Despite numerous publications a lack still exists with regard to these specific recovery methods on physical and haematological parameters. Against this background, the main objectives of this study were firstly, to determine the effects of CWI compared to those of passive recovery (PAR) over a 48-hour period on physical and haematological parameters after an intense anaerobic exercise session in a cohort of male university-level rugby players. Secondly, to determine the effects of CWT compared to those of PAR over a 48-hour period on physical and haematological parameters after an intense anaerobic exercise session in a cohort of male university-level rugby players. Twenty-three rugby players of the North-West University participated in the study. The players were randomly assigned to either a control (n = 11; age: 20.1±0.3 y) or experimental (n = 12; age: 19.9±0.3 y) group. Participants reported to the laboratory where base line measurements were taken on certain physical (vertical jump test (VJT) height, VJT peak speed, VJT peak power and grip strength) and haematological (base excess (BEx), blood lactate (BLa-), calcium (Ca+), bicarbonate (HCO3), haemoglobin, haematocrit, pH level, partial oxygen level (PO2), partial carbon dioxide (PCO2), plasma glucose, potassium (K+), saturated oxygen (SO2), sodium (Na+) and total carbon dioxide (TCO2)) components. Thereafter participants were accompanied to the field to complete an intense anaerobic exercise session, followed by a recovery period of either CWI vs. PAR (week 1) or CWT vs. PAR (week 2). The recovery session comprised of either sitting passively in a still area (PAR), or immersion of CWI (8–10°C), or alternating immersions of five cycles between cold (1 min; 8–10°C) and warm water (3min; 40-42°C), totalling 20 minutes. Exactly three minutes, 24 and 48 hours after the recovery intervention all the measurements were re-taken to assess acute and longer-term effects of recovery. Descriptive statistics were followed by a linear mixed model analysis with an autoregressive 1 heterogeneous (AR1-Heterogeneous) structure, and between-group differences were examined using a one-way analysis of variance (ANOVA). Significance was set at p ≤0.05. Effect sizes were calculated to determine practical significance per recovery intervention as well as within groups. CWI indicated better recovery than PAR, with three out of the nine variables (BLa-, Na+ and haemoglobin) returning at 0 h post-recovery, and five (PO2, plasma glucose, VJT height, VJT peak power, VJT peak speed) only at 24 h post-CWI. In contrast, the PAR-group did not demonstrate recovery in any of the variables at 0 h post-PAR. However, an improvement was seen in VJT height across all time points. Four (BLa-, haemoglobin, VJT peak power and VJT peak speed) out of a possible nine variables recovered at 24 h with an additional two (PO2 and grip strength) variables showing recuperation at 48 h. A significant decrease (p ≤0.05) was seen in VJT height, PO2 and Na+ from post-anaerobic to immediately following either CWI or PAR (except for VJT height). Significant increases (p ≤0.05) were observed in VJT height, plasma glucose, and Na+ from 0 h post-recovery to 48 h post-recovery for both CWI and PAR. PO2 also significantly increased (p ≤0.05) from 0 h to 24 and 48 h post-CWI and for the PAR-group at 48 h. CWI tended to have a faster recovery rate than PAR over a 24-h period. The CWT vs. PAR showed the same trend, at 0-hours, six variables (BLa-, haemoglobin, VJT-height, VJT peak-power, VJT peak-speed and grip strength) was restored to base line, whereas plasma glucose recovered at 24-hours post-CWT. In addition, players’ jump and grip strength performance improved from base line. The PAR-group demonstrated recovery at 0 hours in four variables (BLa-, VJT height, VJT peak-speed and grip strength), and two variables (Na+ and haemoglobin) at 24-hours and plasma glucose at 48 hours. A significant decrease (p ≤0.05) was seen in haemoglobin and BLa- from post-anaerobic to either 24 or 48 hours for both groups. A significant increase in plasma glucose and PO2 from 0 to 24 hours was observed in both groups. No significant intergroup change in physical components was noticed. However, intergroup results indicated CWT to be superior to PAR with statistical significance observed in BLa- and grip strength (p ≤0.05) at various time points. The conclusion drawn from the above-mentioned results is that a recovery session comprising either 20-minutes of CWI or CWT may lead to significantly better physical components and restoration of haematological components in university-level rugby players compared to that of passive recovery. However, a detrimental effect was noticed in some components over the recovery period. / MA (Sport Science), North-West University, Potchefstroom Campus, 2015