This thesis addressed a central theme in evolutionary biology, namely understanding the process of adaptive radiation, using the three-spined stickleback, which has become a model system in this context. In particular, the work concentrated on sticklebacks from several unique populations in the Outer Hebrides that have lost the body armour after which this species was named, lacking dorsal spines, pelvic girdle and spines and lateral plates. A first specific aim was to examine an existing hypothesis about the selective force responsible for armour loss in these populations, namely that it is an adaptive response to low calcium levels. This is in contrast to the selective force favouring armour loss in North American populations, where predation by piscivorous fish is thought to favour armour development and predation by invertebrates to favour armour loss. This was studied by relating variability in protective body armour to calcium concentration at 10 sites with calcium concentrations ranging from 1.2mgCA2+/L to 50.5mgCa2+/L and spread over a wide geographical range. The results confirmed previous studies, providing partial support for the low-calcium hypothesis for Hebridean populations. Thus armour reduction is only found in sticklebacks from low-calcium sites, although not all fish from such sites are unarmoured. Piscine, avian and invertebrate predators were present at all sites, ruling out the predation regime hypothesis. A second aim was to relate variability in risk-taking to variable armour expression, both within and between populations of stickleback. 180 wild-caught fish from 7 sites across Scotland (but mainly concentrated in the Hebrides) were screened for risk-taking behaviour using a well-established testing protocol (quantifying rates of exploration of and movement in a novel and potentially dangerous environment) that is broadly predictive of some aspects of the sticklebacks’ response to a predator. No significant relationship was found between individual risk-taking score and the extent of body armour, either across populations or among individuals within populations. The risk-taking test (chosen because it is simple and easily controlled) only reflects one aspect of anti-predator behaviour and may have been too focused to identity subtle and individual differences in risk-taking.

A series of terraces flanking the Lower Orange River in the study area were deposited after ca. 90% of the incision had occurred, thus only the late stage incision/depositional history of this margin is able to be addressed here. Two principal suites of river terraces are distinguished by their palaeo-courses, bedrock strath levels, overall geometry and clast assemblages: an older, higher lying Proto suite and a younger Meso suite. The Proto suite represents a long, post-Eocene, through the Oligocene into the Early Miocene, phase of incision, followed by a prolonged period of aggradation where up to 90 m of fluvial, diamondiferous deposits accumulated during the Early-Middle Miocene. The Meso suite of deposits represents shorter phrases of incision and aggradation in the Pilo-Pleistocene. The Proto and Meso deposits were built in response to both base level rise and increased supply of material from tributaries draining the Great Escarpment locally, with clast assemblage and downstream fining data indicating the latter to be the more important variable. River incision into bedrock is a topic of great interest to fluvial geomorphologists, although most data are derived from active tectonic settings. The incision of a large river into a plateau surface is relatively rare, the best known example being the Colorado River in the young (6 Ma) Grand Canyon. The Orange River in the study area represents a long-lived example of this setting, with the present day dissected topography having evolved from more confined canyon-like walls following the early incision of the Orange River in the Early Tertiary. Although a long-lived incision, the modern channel is not graded in the study area, and is actively incising. The world-wide dataset of incision rates in modern rivers indicates that the Orange River could have completed its entire incision within less than a million years. The continued downcutting of this river so long after the initial incision event is indicative of the roles of intermittent, ongoing epeirogenesis and/or eustatic influences (both of which cannot be proven at this stage), tributary input from the plateau rim (Great Escarpment) or merely the long tag time involved in landscape adjustment following incision into a plateau surface.

Study of a former industrial land, which was contaminated with chromium, was the major research topic of this study. A survey study of the land was made to evaluate the pH, electrical conductivity ;and percentage of organic matter of soils, available nutrients, total nutrients, available and total chromium and total other heavy metals in the soils. The survey also includes the total nutrients, total chromium and some other heavy metals in the plants and root mat. Soils throughout the site had high total chromium concentrations, high pHs and low plant available nitrogen and low vegetation yields. However, chromium was not detected in the plants. The effects of fertilizer additions were evaluated in two pot experiment studies of these soils using ryegrass as a test crop. The first pot experiment was carried out to look at the response of the soil samples to different combinations of N, P and K fertilizers to determine which fertilizer is limiting the plant growth. The response was measured by dry matter production. Nitrogen was shown to be the limiting factor for growth of the grass in these soils. Alleviating the limiting factor resulted in a yield increase. Since the trend of this increase can not be fully applied to all types of soils and spoils due to differences in nature of the material a second pot experiment was carried out to look at the response of the vegetation to addition of the different rates of nitrogen fertilizer. The results showed that the application of 100 /50 /50 of N/P/K kg/ha fertilizer could obtain the maximum yield for the site except for a soil sample from the base of the east side (sample 4) which did not respond to more than 50 of N kg/ha. Since the changes in the yields from these experiments were not affected by soil extractable chromium in the two experiments the possibility of the direct effect of chromium on plant growth was discounted. The occurrence of the nitrogen turnover and possible toxicity effects of chromium on these processes was assessed during a number of incubation studies. First of all the nitrogen supply power of the soils was evaluated using an incubation test for the nitrogen mineralization rate of the soils from this site. This experiment was done under aerobic conditions. An attempt was also made to look at possible volatization of ammonia due to the pH of these soils.

The effectiveness of using amendments in metal stabilization was determined, and their potential for remediation of contaminated soil was evaluated. A combined approach of evaluating soil and plant metal availability as well as microbial respiration was used as an indication of effectiveness of metal immobilization. This was done by sorption studies, incubation experiments in contaminated media, and greenhouse pot experiments. Batch sorption studies were conducted to evaluate the ability of bone meal, composts, peat, coir and wood bark to sorb Pb, Cu and Zn. Single sorption carried out over a metal concentration range of 0.1 mmol 1-1 using 0.001M and 0.1M Ca(NO3)2 as background electrolytes showed very high sorption of Pb, Cu and Zn by the amendments, but high background salt led to a reduction in the amount of metal sorbed by all amendments. Of the amendments tested, coir, compost and wood bark were most effective. Sorption was evaluated by applying the Langmuir equation, and maximum sorption values were calculated for all amendments. Theoretical maximum sorption of Pb was 87 mg g-1 (0.42 mmol g-1) by coir and green waste compost; Cu was 30 mg g-1 (0.47 mmol g-1) by green waste and general compost, while maximum Zn sorption was 14 mg g-1 (0.21 mmol g-1) in composts, closely followed by 13 mg g-1 (0.19 mmol g-1) in coir. Sorption mixed metal solutions of Pb, Cu and Zn was evaluated in a background salt of 0.001M Ca(NO3)2 only, either at equimolar concentrations of 0.1 mmol 1-1, equimolar concentrations of 1 mmol 1-1, or combinations of metals at either concentration. Metal sorption was reduced in the presence of other metals when compared with sorption in single metal solution. Pb sorption in equimolar solution of 0.1 mmol 1-1 was approximately 50% of that in single solution, Cu was 35%, while Zn was 40% if wood bark was not considered (wood bark sorption of Zn in low equimolar metal was not different from that in single Zn solution). The effect of metals on microbial respiration was evaluated in metal spiked amendments over a ten week period using metal solutions of Pb, Cu and Zn as contaminants. Pb, Cu and Zn toxicity led to an inhibition in CO2 evolved in all amendments, as addition of any amount of Pb, Cu or Zn led to a decrease I amount of CO2 evolved when compared with the non-contaminated amendments. The effect of increasing metal toxicity on CO2 evolution was reflected best in coir, where inhibition increased with an increase I metal concentration. In other contaminated amendments however, the inhibition was highly pronounced once there was metal contamination regardless of the metal concentration.

Geomorphological, geophysical, archaeological and documentary investigations have been employed to establish the variation of sea level change, sediment supply and geological control from the Late-Holocene, through the Historical period to the Present day, in Sanday. Techniques such as Ground-Penetrating Radar and geomorphological Radar and geomorphological surveying have identified a suite of gravel ridge recurves and placed them within their geomorphological context. The provisional regional sea level curve has been updated and clarified following the discovery and successful dating of a submerged forest. This sea level curve was then used to constrain the development of the coast of Sanday into separate time period. A range of archaeological and historical evidence also informed and corroborated the geomorphological evidence to allow the island’s coastal development to be established over the last few thousand years towards the present day, where differential-GPS and sonar techniques allowed these long-term trends to be placed into their modern context. Island-building occurred during Holocene submergence along with other radical changes to the shape and form of the coastline, all reflecting the changing dominance between the three controlling factors. The accepted outcome of submergence is transgression and fragmentation of islands rather than island building and this is wholly a result of a healthy sediment supply at the early stages. However, this sediment source has since begun to diminish and fragmentation, erosion and transgression may well be the outcome of the present trends in Sanday. This coastal change scenario has been projected forward, using climate change scenarios, to raise significant questions not only for Sanday and those regions which have historically experienced submergence, but also for those areas which previously experienced emergence and more recently are starting to be affected by relative sea level rise

This thesis describes a study of a number of aspects of the Nephrops creel fishery. Various aspects have been studied. In particular, work has focused on how the biology of Nephrops affects its catchability in creels, as well as assessing the environmental impacts of the Nephrops creel fishery. A smaller study relating to the physiological effects of the capture and transport of live creel-caught Nephrops, has also been undertaken. Fishery-directed sampling of Nephrops displayed strong seasonal trends in catch composition and catch rate, reflecting patterns in the Nephrops moult and reproductive cycles. Most females were caught in the early spring, following moulting and mating, with catch rates becoming low after spawning in autumn. Catches of males were greatest around February following moulting. Of those animals caught, males were larger than females. These seasonal patterns reflect the exploitation of different components of the stock throughout the year. Fishery sampling also showed there to be considerable stock heterogeneity both among and within creel fisheries. Global positioning system (GPS)-linked data loggers fitted to selected fishing boats provided a more detailed assessment of spatial variability in catch rate. Results showed both effort and landings per unit effort (LPUE) to be patchily distributed in the area studied, further illustrating considerable stock heterogeneity throughout the area. Both approaches illustrated that catch rate varied with sediment type, with high catch rates of small animals on sandy to firm mud and high catch rates of large animals on softer mud. Additionally, population modelling indicated that, in the areas studied, Nephrops are not currently being growth overfished. Behavioural observations in both the field and laboratory indicated a low probability of entry to creels by approaching Nephrops, particularly if other crustacean species were inside the creel. Larger Nephrops appeared to have a greater threshold for disturbances such as and the presence of conspecifics or other species as well as reduced gear avoidance, suggesting that Nephrops creels select larger animals in the population. Using sea pens as an indicator of physical disturbance of the sea bed showed that impacts from creeling were low. The sea pens Virgularia mirabilis and Pennatula phosphorea were caught in moderate quantities in the creel fishery, but were still observed in high densities on creel grounds. Comparison with trawled areas showed some differences in density, the most notable being that the tall sea pen Funiculina quadrangularis was less abundant on trawled grounds, indicating an adverse effect of bottom-towed gear. Bycatch was assessed in two distinct fisheries and varied both between and within areas; however, levels of bycatch (both target and non-target species) in all areas were much lower than previous estimates from the trawl fishery. Additionally, in contrast to the trawl fishery, commercially exploited fish made up a small proportion of the bycatch in the Nephrops creel fisheries studied. The survival of Nephrops discards is considered to be high, although preliminary results suggest that predation by seabirds may cause significant mortality. The effects of ‘ghost fishing’ were investigated experimentally at two sites and it seemed that lost creels do not constitute a serious issue in this fishery. Creels were found to be very selective for their target species, with both target and non-target species being able to escape. Only a few crabs and a small proportion of the captured Nephrops died in the creels, indicating no evidence of a ‘re baiting’ effect from dead animals. Stress associated with the capture, storage and live transport of creel-caught Nephrops was found to be greatest during the transport process, during which Nephrops are kept out of water for long periods of time. Temperature was particularly important, suggesting cooling prior to and during transport was essential in order to ensure their survival. Reduced salinity was found to be a major source of stress. An assessment of the management measures implemented in the Torridon creel fishery show that escape gaps placed in creels are effective in enabling smaller Nephrops and other bycatch species to escape. Limiting effort of individual fishermen has been successful, but this has been followed by an increase in the number of boats fishing within the area, leading to an overall increase in effort. Management measures (both statutory and voluntary) currently applied in the Torridon area are discussed and considered in relation to other areas. It is concluded that creel fishing areas need to be considered on a case-by-case basis, accounting for biological characteristics of individual stocks, as well as management issues at a local scale. The findings of the present study are discussed in the context of providing a detailed description of the characteristics of the Nephrops creel fishery on the west coast of Scotland. Findings are also discussed in relation to other crustacean creel fisheries, enabling issues directly relevant to the specific fishery to be considered in a much broader context. The present study has been particularly valuable in a wider context, as Nephrops are found in a habitat which is very different from the majority of other commercially exploited crustaceans, and their life history characteristics are also different. This study provides an ideal platform to assess what general principles from other creel fisheries apply to the Nephrops creel fishery, as well as what characteristics are unique to this fishery.

Sellafield in West Cumbria is the potential site of a repository for radioactive, Intermediate Level Waste (ILW). The proposed repository lies at 650 m beneath the ground surface to the west of the 1000 m uplands of the Lake District. The fractured Borrowdale Volcanic Group (BVG) host rock is overlain by a sequence of Carboniferous and Permo-Triassic sediments. Fresh, saline and brine groundwaters exist in the subsurface. Upward trending fluid pressure gradients have been measured in the area of the potential repository site. Steady-state, 2-D simulations of fluid flow were undertaken with the OILGEN code. Topographically driven flow dominates the regional hydrogeology. Subsurface fluid flow trended persistently upwards through the potential repository site. The dense brines to the west of the site promoted upward deflection of groundwaters. The groundwater flow rate through the potential repository site was dependent upon the hydraulic conductivity of the BVG. Calibration of the model was achieved by matching simulated subsurface pressures to those measured in-situ. Emergent repository fluids could reach the surface in 15,000 years. The measured BVG hydraulic conductivity is up to 1000 times too high to be simply declared safe. Geochemical simulations, with Geochemist's Workbench?, showed natural BVG groundwaters display redox disequilibrium. The in-situ Eh is most probably +66 mV. Pyrite, absent from rock fractures, would not enforce a reducing -250 mV Eh. Steel barrels and alkaline cement are intended to geochemically retain 2.5x106 kg of uranium. Simulations of repository cement/BVG groundwater interactions produced pH 10 at 80°C but no change in the +66 mV Eh. Steel barrel interactions produced an alkaline fluid with Eh -500 mV. Uranium solubility in the high pH repository near field was as high as 10-2.7 M, regardless of steel interactions. Uranium solubility adjacent to the repository (pseudo near field) was controlled by Eh; ranging from 10-13 M in the presence of steel, to 10-2.7 M with no steel. Uranium retention is controlled only by steel barrel durability. Oxidising, natural BVG groundwater will enhance steel barrel destruction. Distant from repository (far field) uranium solubility was 10-5.4 M if Eh was as measured in-situ. Thermodynamic data variations affect the calculation of uranium solubility; uranium near field solubility can be as high as 10-1.4 M. Uranium solubilities in near-field high pH groundwater could be more than 600 times greater than the 10-5.5 M used by the UK Nirex Ltd. in their safety case simulations.

One of the most catastrophic natural hazards which can devastate coastal zone communities is the tsunami. The risk of tsunami devastation can be mitigated by reconstruction and quantification of past tsunamis, but this requires identification and analysis of past tsunami magnitudes and dates even from historical times. The interpretation of geological records of tsunamigenic deposits is the core theme explored in this thesis for the characterisation of palaeotsunamis. Three key elements: identification of palaeotsunamites, dating their deposition and determination of magnitude are needed for reconstruction and quantification of palaeotsunamis. While several studies have described criteria for identification of tsunamigenic sediments, much less research has been carried out on reconstruction of palaeotsunamis. Sediment characteristics, their depositional configuration and extent of the inundation area on the coast give infOlmation on hydrodynamic conditions of tsunami waves. This study has developed a method to estimate tsunami risk by reconstructing and quantifying palaeotsunamis from tsunamigenic sediments on the Sri Lankan coast rising sedimentological and paleontological characteristics, Ground Penetrating Radar (GPR), and optically stimulated luminescence (OSL) dating techniques. The 2004 tsunami records were used as a control for the study. Distinctive tsunamigenic sediment signatures were recognised. Three palaeotsunami events were identified and dated at ISO (Krakatua), 2550±190 and 3170±320 years BP and correlated with historical and archaeological records. The recurrence interval of c 600 years postulated for the Indian Ocean was confirmed by this study and the oldest event recorded to date in the Indian Ocean was recognised at 3170±320BP. The method developed here based on reconstruction of palaeotsunamis using sedimentological records, GPR and OSL techniques enables estimation of inundation distance, recurrence interval and consequently the wave characteristics of palaeotsunamis which can be used to estimate tsunami risk for any coast.

This research focuses on atmospheric and fluvial dispersal of Pb and Zn from an abandoned mine at Tyndrum, Scotland, which potentially acts as a significant source of contamination to the surrounding area. Concentrations of Pb and Zn in tree bark samples and peat profiles were measured to assess aerial deposition and fallout around the main mine site. Dispersal of contaminants through fluvial transport was assessed by analysis of river water and sediment on site and in the main river system draining the area, extending 25 km downstream from the mine area. Attempts were also made to determine whether the contamination is due to contemporary dispersal of material from the abandoned mine waste dumps, or originates from past deposition. Pb and Zn concentrations in tree bark from Scots pine (Pinus sylvestris) were high, but decreased with increasing distance up to approximately 100 m from the main dumpsite. Concentrations reduced markedly beyond this distance, possibly owing to the density of the forest stand. It is suggested that tree bark samples provide a useful medium for monitoring and quantifying contemporary aerial dispersal. Distributions of Pb and Zn within peat soil profiles provide information of past atmospheric deposition. Subsurface peaks of Pb and Zn can be linked to the period when mining was active during the 19th and early 20th centuries using the 210Pb dating method. The dispersal of Pb and Zn within the fluvial system was assessed by measuring concentrations of the contaminants in the solution, suspended particle and bed sediment phases. It was found that Pb and Zn are mainly transported in suspension in the 1.2-53 m suspended sediment fraction and are consequently deposited throughout the dispersion pathway in riverbed, lake and riverbank sediments. The contaminant Pb in an overbank core was confirmed as originating from the Tyndrum mine on the basis of its 206Pb/207Pb isotope ratio characteristics. This confirms a previous hypothesis that waste from the mine is an important contributor to Pb contamination over the entire length of the river system as far as Loch Tay. Thus overall, the investigation concludes that although the atmospheric dispersal of the contaminants is mostly contained within the vicinity of the Tyndrum main mine, the fluvial system remains a significant pathway for dispersal of Pb and Zn from the Tyndrum waste and that the presence of these metals within the river may persist for many years to come.

This research examined the impact which onshore windfarms sited on peat-based soils have on streamwater carbon (C), phosphorus (P) and nitrogen (N) dynamics. Significant disturbance to peatland arises through the excavation of borrow pits, construction of access tracks, insertion of turbine bases and associated deforestation during windfarm development – potentially increasing the transfer of C, P and N from terrestrial stores to the stream network. To identify which impacts occur, streamwater samples from nine catchments draining the Whitelee windfarm, Scotland, Europe’s largest onshore windfarm, were collected approximately bi-monthly from October 2007 to September 2010 during and after windfarm construction, building on pre-disturbance data from Waldron et al. (2009). The samples were analysed for dissolved organic carbon (DOC), particulate organic carbon (POC), total organic carbon (TOC), soluble reactive phosphorus (SRP), total phosphorus (TP) and nitrate (NO3-). Time series were constructed and annual streamwater exports were calculated so that inter-catchment and annual differences could be detected. DOC concentrations ranged from 2.9 mg L-1 to 57.1 mg L-1 and DOC exports ranged from 9.0 g m-2 yr-1 to 42.3 g m-2 yr-1. POC concentrations ranged from 0.09 mg L-1 to 23.4 mg L-1 with POC exports ranging from 0.80 g m-2 yr-1 to 3.93 g m-2 yr-1. DOC exhibited seasonality with maximum concentrations and exports towards the end of each summer. Harmonic regression analysis of the TOC data indicated a slight increase during the maximum phase of the seasonal cycle, coincident with windfarm-related disturbance observed in one catchment only. Regardless of windfarm development, streamwater DOC exports for four peatland-dominated catchments were observed to exceed typical values of C sequestration rate for Scottish peatlands over the four year time series. SRP concentrations ranged from 1 ug L-1 to 289 ug L-1 and exports from 12 mg m-2 yr-1 to 104 mg m-2 yr-1 with TP concentrations and exports ranging from 2 ug L-1 to 328 ug L-1 and exports from 25 mg m-2 yr-1 to 206 mg m-2 yr-1 respectively. In two catchments where windfarm-related clear-felling and extensive brash mulching were carried out, as much as a tenfold increase was observed from June 2007 in P concentration, coincident with the timings of windfarm-related forestry operations. The water quality status of these two catchments declined from “good” to “moderate” in terms of the Water Framework Directive (2000) UK Technical Advisory Group Environmental Standards for SRP in Rivers, and had still not shown a full recovery after a further two years. NO3- concentrations ranged from 0.001 mg L-1 to 2.44 mg L-1 and exports from 0.07 g m-2 yr-1 to 1.64 g m-2 yr-1. Harmonic regression analysis indicated a potential impact on streamwater NO3- concentration through a change in the seasonal pattern observed in three catchments during 2007-2008, coinciding with windfarm-related disturbance. To determine the most likely controls of C, P and N, a geographic information system (GIS) analysis was employed to describe the physiography of each catchment and to quantify the extent of windfarm-related disturbance. Multiple linear regression analysis was performed using median concentration and export for a low-disturbance phase from June 2006 to August 2007, and a maximum-disturbance phase from September 2007 until May 2009, with the catchment characteristics from the GIS analysis to identify potential impacts of windfarm-related disturbance. The percentage of the catchment which was HOST class 15 and 29, both peat-based soil types, was observed to influence streamwater C, with the proportion of the catchment which was pasture observed to influence streamwater N. Windfarm-related disturbances were also found to control streamwater dynamics. The extent of deforestation was observed to greatly increase streamwater P concentration and that there was a smaller increase in C, with consequent impacts on SRP and POC export. The source of this additional C and P resulted most likely from forestry operations, namely, clear-felling large areas of catchment and extensive brash mulching associated with the windfarm habitat restoration, with new organic material available for decomposition and the potential for erosion of the newly-exposed soil surface. Residual fertiliser used to establish the conifer trees, the reduced vegetation uptake of soil P and P release from the roots of the felled trees are three further sources of P in streamwater. The distance to the nearest disturbance was also found to influence streamwater dynamics. This research has shown that windfarm-related infrastructure can also influence streamwater chemistry, although exerting a less obvious impact: increasing access track length was correlated with decreasing POC and P concentration causing subsequent decreases in export. This is likely to be caused by the effective use of settlement ponds, flocculation blocks and ditch blocking in order to reduce the amount of particulate matter reaching the stream network and potentially through the adsorption of P by the access track construction material. Windfarm-related disturbance did not influence N dynamics; NO3- concentration was strongly correlated with HOST class 24 and the proportion of the catchment which was pasture, and NO3- exports were influenced by the flow length per catchment area, the percentage of coniferous forest cover and the extent of pasture. Two recommendations for best practice at future windfarm developments on peatland are made: firstly, monitor C, P and N in streamwater in all catchments before, during and after windfarm construction on C rich soils as part of EIA process in order to ensure that water quality is maintained in rivers, to determine whether discharges from windfarm developments should require to be licensed and to improve the accuracy of C payback time estimates; and secondly, minimise brash-mulching to reduce the impact on streamwater P. Furthermore, some suggestions for future research were proposed, including: plot studies to determine the best practice mitigation measures for P release in peatland catchments, longitudinal catchment studies, investigation of the relationship between access track construction material and streamwater dynamics, installation of continuous monitoring equipment along with a sampling regime which targets high flow events, examination of the changing stiochiometry, quantification of inorganic C and gaseous forms of C, and measuring catchment C sequestration rates.