The Pliocene Epoch (5.33–2.59 Ma) is characterised by climatic conditions similar to those predicted for 2100, with enhanced warming in the (sub-)Arctic. The climate evolution at high latitudes is not well understood due to the sparsity of time-continuous palaeoenvironmental records. This study provides new records of Pliocene vegetation changes in Arctic Norway and the variability of the Norwegian Atlantic Current based on analyses of terrestrial and marine palynomorphs from ODP Site 642 (Norwegian Sea, 67°N) to assess climate variability and identify different scale forcing mechanisms. The Piacenzian pollen record (3.60–3.14 Ma) shows vegetation changes between cool temperate and boreal forests during warmer-than-present and similar-to-present climate phases, respectively, implying shifts of the northern deciduous/mixed forest limit of 4–8° latitude. During warm phases, warmest month temperatures were 8–14°C higher than present. The development of peatlands during cooler phases may have amplified the cooling through CO2-drawdown and positive vegetation-snow feedbacks. The high regional and hemispheric-wide climate variability highlights the importance of well-dated, high-resolution records for regional to global palaeoenvironmental reconstructions and data-model comparisons. Long-term Pliocene vegetation changes (5.03–3.14 Ma) reveal a continuous decline of thermophilic elements over successive warm phases, supporting the notion of long-term climate cooling caused by decreasing CO2 concentrations. This cooling is superimposed on shifts between cool temperate and boreal climate phases on multi-millennial timescales. Minima in eccentricity (400-ka), together with low-amplitude obliquity/precession cycles are associated with the development of boreal conditions. At 4.56 Ma, a marked decline in pollen influx suggests atmospheric circulation changes in response to the shoaling of the Central American Seaway, a hypothesis supported by model results. Subsequently, changes in northward heat transport via the North Atlantic Current strongly affected vegetation changes. The Pliocene climate evolution represents the later part of late Neogene cooling instead of a reversal of that trend. Dinoflagellate cyst assemblage changes (3.320–3.137 Ma) indicate variations in Atlantic and Arctic water influence, corresponding to cool temperate and boreal terrestrial climatic conditions in Arctic Norway, respectively. These records emphasise a high climate variability on glacial-interglacial timescales and linkage of both marine and terrestrial environmental changes.

The overlap of seasonal snow and forests contributes significantly to global snowmelt, largely driven by net radiation, the combination of shortwave and longwave radiation. In sub-canopy longwave radiation models, unavailability of forest canopy temperature measurements often results in locally measured air temperatures being used to represent the temperature of the emitting canopy. The validity of this assumption was tested using extensive field measurements in three sub-canopy mid-latitude alpine environments, and resulted in improvements to model simulations of sub-canopy incoming longwave radiation. Three different radiometer configurations (stationary distributed, stationary linear, and moving linear) were simultaneously compared in a spruce forest in the eastern Swiss Alps, capturing the annual range of sun angles and sky conditions. The two linear configurations showed the greatest similarity in shortwave transmissivity, and the measurements of longwave enhancement were largely similar between all three configurations. Simulation of incoming longwave radiation at a point commonly partitions the up-looking hemispherical view between radiation coming from the sky (the sky-view fraction, Vf) and the forest canopy (1 - Vf). In this two-part model, using air temperature as a proxy for tree temperature at three forested sites with Vf < 0.3 resulted in model underestimations, representing canopy temperatures elevated above air temperature. Importantly, these errors were largest during sunny, clear-sky conditions, particularly along sun-lit canopy discontinuities. However, in denser canopies, measured tree trunk temperatures were cooler than local air temperature. Model estimations were improved by applying a bulk offset to air temperature (+3�C), reducing error from 11 Wm-2 to 4 Wm-2. Within sun-lit discontinuous forests, measured canopy temperatures varied between 5-25�C above air temperature and errors of the two-part model were as high as 40 Wm-2. Point-scale simulations of longwave radiation were improved by explicitly accounting for tree trunk temperatures within the canopy-view fraction, creating a three-part model (sky, trunk and canopy). Modelled estimates of incoming longwave radiation beyond the point-scale were improved through extensive canopy temperature measurements using infrared thermal imagery around forest gaps. A parametrisation to estimate canopy temperature using sub-canopy shortwave radiation and air temperature was developed for modelling sub-canopy incoming longwave radiation using the two-part model along canopy discontinuities. These findings provide a framework for incorporating sub-canopy longwave radiation within larger scale snowmelt models. Particularly, it is important to represent both canopy discontinuities, as well as canopy temperatures at sub-daily time steps. Exclusion of these factors could lead to inaccurate estimations of snowmelt initiation and runoff rates.

The significance of ponds in the terrestrial carbon cycle has received increasing attention in recent years. Evidence suggests that ponds exhibit rates of biogeochemical cycling orders of magnitude greater than larger water bodies and, cumulatively, the storage of organic carbon (OC) in small ponds may equal or possibly surpass that of large water bodies. This project furthers our understanding of OC storage within ponds, combining survey and experimental approaches to accurately quantify sediment carbon stocks and accumulation rates. It incorporates four distinct, yet complimentary components aiming to: i) Evaluate the accuracy of estimating OC storage in entire ponds from sediment cores; ii) Monitor physicochemical dynamics and quantify OC storage across newly constructed ponds; iii) Quantify OC storage across a suite of mature ponds and assess the impact of vegetation community development; iv) Identify variations in microbial communities between different ponds in relation to sediment physicochemistry and vegetation coverage, exploring the implications for OC storage and burial. Carbon stocks were surveyed in 12 mature ponds across an experimental field site at Druridge Bay, Northumberland. Comprehensive historical ecological data was used to separate these ponds into three distinct groups based on hydrology and vegetation. One pond was selected from each of the resulting three groups and exhumed in its entirety to accurately quantify OC storage. Three sediment cores were taken beforehand in a novel attempt to evaluate the percentage difference between sediment core estimates and whole pond sediment OC storage. Whole pond exhumation suggests that the three ponds stored between 1565 – 2288 g OC m2, whilst results from the cores alone gave estimates within a 10-15% range. A further three ponds from each group were selected to quantify burial rates using sediment cores. Results suggest the ponds have stored between 1413 – 4459 g OC m2 over 20 yrs, equating to around 67 – 212 g OC m2 yr-1. OC storage was greater in ponds that had undergone the fastest establishment of vascular plant communities. Three new ponds were constructed at the Druridge site. Physicochemical parameters were monitored at approximately fortnightly intervals across a period of three years. All three ponds were hyper-eutrophic, dominated by algae. However, OC storage was negligible, further suggesting that OC burial is only significant upon the establishment of vascular plant communities. Sediment samples were subject to 16s rRNA analysis to identify microbial communities involved in carbon cycling. Variations in microbial community composition between ponds were observed and showed complex relationships with sediment physicochemistry and vegetation coverage. Microbial diversity was significantly higher in ponds storing more OC. Ponds dominated by Juncus vegetation, had lower diversity and a greater abundance of facultative anaerobic bacteria, and stored less OC. The intense rates of OC burial observed in this study demonstrate the functional capacity of constructed ponds to operate as significant sinks of OC. High rates of OC accumulation compared to the surrounding terrestrial landscape highlights the potential for their construction across landscapes to act as versatile, yet effective carbon mitigation features.

Small water bodies (SWBs) are an important biogeochemical sub-compartment of the global carbon cycle that has been given little or no attention. They have similar capabilities to oceans, large lakes and river systems to exist in flux and could store more carbon in their sediments than the above systems. This research is aimed at determining the number and surface area of inland water bodies in Northumberland, the carbon stocks in the sediments of those water bodies and the microbial influence on the carbon stocks. These further define the Northumberland regional carbon stocks, the level of allochthonous and autochthonous carbon influence in the regional carbon stocks and the effects of surrounding vegetation, sediment wetness, dry bulk density, microbes, anoxia, pond permanence and temporariness on carbon stock variations. The importance of SWBs is in their abundance and the ability to estimate this will aid the understanding of their actual contributions to the global carbon cycle as a net source or sink. Using Landsat-8 and World Imagery data, number and surface area of water bodies in Northumberland were identified by manual digitising of water bodies on ArcGIS 10.0. This showed variation in number and surface area of water body abundance with respect to imagery types, time and scale of analysis. The correctness of estimating water body abundance is subject to the continuous temporal change of small water body abundance. The continuous changes are associated with the nature of water bodies, regional/sub-regional landscape (hypsometry), precipitation and land use. Carbon stock in Northumberland was determined by Total Elemental Analyser (TEA) combustion of sediment from various types and sizes of ponds collected from Druridge Bay, Northumberland. Carbon stocks varied in each ponds type and size range. These variations were influenced by the prevailing environmental/physical, biological and chemical/biochemical factors in pond sediments. The microbial community drives carbon stock by altering the microbial community structure, allochthonous and autochthonous carbon processes and the oxygenation in the ponds. PCR pyrosequencing targeted at the 16s rRNA gene showed diversity in the microbial composition of the Northumberland pond sediments and the results showed a varying level of anoxia triggered by factors such as anoxic Proteobacteria, Bacteroidetes, Chloroflexi, Cyanobacteria and Chlorobi dominance. These dominant phyla also influenced other phyla to develop anoxic ecological relationships and produce predominantly anoxia based processes like methanogenesis and fermentation. Anoxic pond bottoms were also triggered by high terrestrial inputs amongst other factors. This research shows for the first time that carbon stock in a region’s SWBs varied because of numerous physical/environmental, chemical and biological factors. Also, SWBs stock carbon from the terrestrial environment and in-situ aquatic processes. Northumberland water body distribution has shown that more carbon is stocked in the small sized water body systems than larger water body system and their global abundance places them as an important carbon capture mechanism.

Internationally publicized impacts upon human health associated with exposure to potentially harmful elements (PHE) have been reported globally. Particular concern has surrounded the exposure to Pb indicated by the presence of highly elevated concentrations of Pb in blood and hair samples amongst internally displaced populations (IDPs) in Mitrovica, Kosovo, following the Kosovan War (Runow, 2005). The exposure risk to humans depends in part on the potential of the PHE to mobilise from its matrices in the human digestive and respiratory systems (bioaccessibility) and enter the blood stream (bioavailability). This study utilizes physiologically based in-vitro extraction methods to assess the bioaccessibility of PHEs in surface soils and metallurgical waste in Mitrovica and assesses the potential daily ingestion of soil-bound PHEs (As, Cd, Cu, Mn, Pb, and Zn) and inhalation (Pb) of particulate matter < 10 μm (PM10). A total of 63 samples (52 surface soils and 11 mine/smelter waste) were selected based on PHE loadings and their spatial distribution. For the in-vitro oral bioaccessibility 0.3 g subsamples were analysed using the UBM method (adopted by BARGE, Wragg et al., 2009). The mean bioaccessibility of Cd, Pb and Zn in the gastric phase is 51 %, 57 % and 41 %, respectively, compared to 18 %, 16% and 14%, respectively, in the gastric-intestinal phase. The trend with As and Cu data is less consistent across the sample locations, with a mean of 20 % and 22 % in the gastric phase and 22 % and 26 % bioaccessibility in the gastric-intestinal phase, respectively. To investigate the role of mineralogy in understanding the bioaccessibility data subsamples (< 250 μm) were submitted to the British Geological Survey, Nottingham, for X-ray diffraction (XRD) analyses. Samples associated with lower bioaccessibilities typically contain a number of XRD-identifiable primary and secondary mineral phases, particularly As- and Pb-bearing arseninian pyrite, beudantite, galena and cerrusite. For the inhalation bioaccessibility, PM10 subsamples were extracted from 33 samples using a locally developed laboratory based wet method. The 0.3 g PM10 subsamples were analysed using a new tracheobronchial fluid and protocol developed as part of this study. The bioaccessibility of Pb for all the 33 samples tested ranged from 0.02 to 11 % and it is consistent with a range (0.17 to 11 %) previously reported by Harris and Silberman (1988) for Pb bioaccessibility in inhalable particulates (< 22 μm) using canine serum. Quantification of the potential human exposure risk associated with the inhalation and ingestion of soil-associated PHEs indicates the likely possibility of local populations exceeding the recommended tolerable daily intake of Pb. IEUBK model (USEPA, 2007) predicted mean blood Pb concentrations for children based on bioaccessible (ingestion) data are above the CDC level of concern (10 μg/dL).

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Thesis (M.Sc.)(Meteorology)--University of Pretoria, 2004. / Title from opening screen (viewed March 11th, 2005). Summaries in Afrikaans and English. Includes bibliographical references.

Thesis (M.S.)--Florida State University, 2005. / Advisor: Sharon E. Nicholson, Florida State University, College of Arts and Sciences, Dept. of Meteorology. Title and description from dissertation home page (viewed Jan. 26, 2006). Document formatted into pages; contains ix, 58 pages. Includes bibliographical references.

Thesis (M.S.)--University of Wisconsin, 1966. / This research was partially supported by the United States Weather Bureau under contract WBG-27. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaf 36).