A chemical survey of standing waters in south-east England, with reference to acidification and eutrophication

This study looks at the distribution and magnitude of acidification and eutrophication in south-east England where there are no natural lakes but a large number of shallow artificial ponds. The study area is defined as the region lying within a 100 km radius of central London but excluding the area within the M25 motorway. Water samples were taken from 120 sites between mid-January and the end of February 1990, with a subsequent monthly survey of a subset of 31 of these waters. Twelve chemical variables were measured in the laboratory using standard techniques. PH values for the full dataset ranged from 3.2 to 8.4, although the majority of sites had pH values in the range 7.0 to 8.5; only five sites had a pH of less than 6.0. The five low pH sites expectedly had low alkalinities and are the only sites with values below 0.1 meq per litre. Concentrations of calcium, sodium, potassium, magnesium, chloride, sulphate and nitrate had normal distributions. The majority of sites had total phosphorus concentrations in the range 25 to 200 mu g per litre, although 10 sites had concentrations above 400 mu g per litre. The low number of acid sites suggests that surface water acidity is not a widespread regional problem in south-east England. However the survey shows that a large number of standing waters in the region have high total phosphorus and nitrate concentrations, and 89% may be considered moderately to considerably eutrophic

Diatom analysis of River Thames foreshore deposits exposed during the excavation of a Roman waterfront site at Pudding Lane, London. Report for the Department of Urban Archaeology, Museum of London

Eighty-seven diatom taxa including marine, brackish, and freshwater forms were identified from foreshore sediments accumulated against pre-AD 100 quay structures exposed during the excavation of an early Roman waterfront site in the city of London. The spectra indicate that the Roman port was probably established close to the tidal head of the river

Languages Canada: The Paradoxes of Linguistic Inclusivity – Colonial/Founding, Aboriginal and Immigrant Language Rights

This article approaches the question of inclusivity in contemporary Canadian society through the lens of official language policy. Although Canada has well-developed bilingual policies for English and French at the federal and provincial levels, the only jurisdictions which (at the time of writing) afford official language status to Aboriginal languages in addition to English and French are the Northwest Territories (nine First Nations and Inuit languages) and Nunavut (the Inuit language/s). The article situates the development of these territorial language policies within the contexts of Canadian history, the emergence of language policy more generally in Western societies, and the human rights revolution, and offers a tentative evaluation of them in terms of inclusivity, noting the paradox that inclusive recognition of the territories’ indigenous languages has not been extended to the immigrant languages, whose speakers partly outnumber the smaller Aboriginal-language communities, as well as the daunting problems faced in turning official recognition into practical implementation

The acidification of Scottish Lochs and the deprivation of critical sulphur loads from palaeolimnological data

A decade ago very little was known about acid lochs in Scotland. The implicit assumption was that they were largely free from pollution. In recent years the position has changed and we now have large bodies of data on the chemistry and biology of upland lochs (Harriman et al. 1986, Maitland et al. 1987, Battarbee et al. 1988) and clear evidence for the recent acidification of many sensitive sites (Flower and Battarbee 1983, Battarbee et al. 1985, Flower et al. 1987, Battarbee et al. 1988)

Acceleration of Solar Energetic Particles in coronal shocks through self-generated turbulence

The acceleration of solar energetic particles (SEPs) by flares and coronal mass ejections (CMEs) has been a major topic of research for the solar-terrestrial physics and geophysics communities for decades. This thesis discusses theories describing first-order Fermi acceleration of SEPs through repeated crossings at a CME-driven shock. We propose that particle trapping occurs through self-generated Alfvén waves, leading to a turbulent trapping region in front of the shock. Decelerating coronal shocks are shown to be capable of efficient SEP acceleration, provided seed particle injection is sufficient. Quasi-parallel shocks are found to inject thermal particles with good efficiency. The roles of minimum injection velocities, cross-field diffusion, downstream scattering efficiency and cross-shock potential are investigated in detail, with downstream isotropisation timescales having a major effect on injection efficiency. Accelerated spectra of heavier elements up to iron are found to exhibit significantly harder spectra than protons. Accelerated spectra cut-off energies are found to scale proportional to (Q/A)1.5, which is explained through analysis of the spectral shape of amplified Alfvénic turbulence. Acceleration times to different threshold energies are found to be non-linear, indicating that self-consistent time-dependent simulations are required in order to expose the full extent of acceleration dynamics. The well-established quasilinear theory (QLT) of particle scattering is investigated by comparing QLT scattering coefficients with those found via full-orbit simulations. QLT is found to overemphasise resonance conditions. This finding supports the simplifications implemented in the presented coronal shock acceleration (CSA) simulation software. The CSA software package is used to simulate a range of acceleration scenarios. The results are found to be in agreement with well-established particle acceleration theory. At the same time, new spatial and temporal dynamics of particle population trapping and wave evolution are revealed.Siirretty Doriast

Mountain lakes, pristine or polluted?

This paper presents conclusions from a number of collaborative research projects on remote mountain lakes across Europe funded by the European Union. In particular it describes how the sediment records of key research sites can be used to identify the timing, extent and impact of air pollution on lakes by acid deposition, trace metals and trace organic compounds. It also describes recent work that aims to assess the impact of 20th century climate change on these lakes and whether the changes observed are the result of natural climate variability or the enhanced greenhouse effect.Este artículo presenta las conclusiones de varios proyectos de colaboración en el estudio de lagos de montaña remotos distribuidos por Europa y financiados por la Unión Europea. De forma particular describe como el registro sedimentario de varias localidades clave puede ser usado para identificar el cambio temporal, la intensidad y el impacto de la contaminación atmosférica en lagos por deposición ácida, metales traza y compuestos orgánicos trazadores. Este trabajo también describe el trabajo reciente para ayudar a valorar el impacto del cambio climático del siglo XX sobre estos lagos y si los cambios observados son el resultado de la variabilidad climática natural o el aumento del efecto invernadero

A semi-analytical foreshock model for energetic storm particle events inside 1 AU

We have constructed a semi-analytical model of the energetic-ion foreshock of a CME-driven coronal/interplanetary shock wave responsible for the acceleration of large solar energetic particle (SEP) events. The model is based on the analytical model of diffusive shock acceleration of Bell (1978), appended with a temporal dependence of the cut-off momentum of the energetic particles accelerated at the shock, derived from the theory. Parameters of the model are re-calibrated using a fully time-dependent self-consistent simulation model of the coupled particle acceleration and Alfvén-wave generation upstream of the shock. Our results show that analytical estimates of the cut-off energy resulting from the simplified theory and frequently used in SEP modelling are overestimating the cut-off momentum at the shock by one order magnitude. We show also that the cut-off momentum observed remotely far upstream of the shock (e.g., at 1 AU) can be used to infer the properties of the foreshock and the resulting energetic storm particle (ESP) event, when the shock is still at small distances from the Sun, unaccessible to the in-situ observations. Our results can be used in ESP event modelling for future missions to the inner heliosphere, like the Solar Orbiter and Solar Probe Plus as well as in developing acceleration models for SEP events in the solar corona

The influence of sanitary and other social changes on the eutrophication of Lough Erne since 1850: Project introduction and a consideration of the potential role of metabolic wastes

Recent limnological studies of Lough Erne have suggested that the lake is highly producdve(F.B.I.u.1975.Gibsonet a1. 1980) and that the present level of productivity ig a result of increasing nutrient inputs to the llike over the past lob years or so (ila't:tarbee; 1977). It is the purpose of this project. funded by S.S.R.C. grant HR 7437. to document the deinographic. dietary and sanitary changes in the catchment since 1850 and to evalua.te the relative importance of 'domestic metabolic waste as a source of nutrient supply. This report provides an introduction to the project and considers the methods involved in estimating the minimum phosphorus output from households in the catchment ror the period 1851 - 1971