1,505 research outputs found
The acidification of Scottish Lochs and the deprivation of critical sulphur loads from palaeolimnological data
No full textA 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)
Critical loads of acid deposition for UK freshwaters: Report of the Critical Loads Advisory Group, sub-group on Freshwaters, for the UK Department of the Environment
No full textFollowing a decade of intensive research on the causes, mechanisms and extent of surface water acidification in the United Kingdom, and the general acceptance that acidification is a major environmental problem, attention is now focused on ameliorative strategies and their potential success. Within the Department of the Environment's research programme this comprises two components: defining and mapping the critical loads of acidity for freshwaters, and monitoring selected freshwaters to evaluate the long-term benefits of reducing acidifying emissions from power stations. This report presents the interim results of the first of these, the critical loads programme. Approximately 1600 water bodies throughout the UK have been sampled and analysed to enable critical load values for the most sensitive sites within grid squares to be derived and mapped as required by the UNECE (United Nations Economic Commission for Europe). A validation study of these primary survey data is now being carried out. When complete, new critical load maps will be published showing sites where modifications are needed. In this report we refer only to acidity that is attributable to sulphur deposition. However, the acidification status of some freshwaters is also influenced by nitrogen deposition. For these sites the values shown on the critical load exceedance maps will be under-estimates. Current research is addressing this issue, and future critical load exceedance maps will show values for total acidity (sulphur+ nitrogen}. All the work presented here has benefitted from discussion within the DoE's Critical Loads Advisory Group (CLAG) and the CLAG Sub group on Freshwaters. I should like to thank members of both those groups for their contributions and for their help over the last four years. I should also like to thank the DoE for funding
Acidification in the Cairngorms and Lochnagar: a palaeoecological assessment
No full textSensitive lakes in areas of the United Kingdom with moderate to high sulphur
deposition have been acidified since the middle of the nineteenth century- (Battarbee et al.
1988). Regions such as Galloway, south west Scotland (eg. Flower and Battarbee 1983,
Flower et al. 1987), Wales (eg. Battarbee et al. 1988, Fritz et aL 1990), Cumbria (eg.
Battarbee et al 1988, Atkinson and Haworth 1990), and Rannoch Moor in the central
Scottish Highlands (eg. Flower et al 1988) have been affected. This study extends the
geographical survey of lake acidification to the Caimgorm and Lochnagar regions of north
east Scotland (Figure 1). The Caimgorms and Lochnagar are areas of considerable
conservation value, forming the largest single area of land over 1000 m in the UK. The
Caimgorm mountain plateau is a National Nature Reserve, noted for its alpine flora and
fauna, whilst the Lochnagar range is a Scottish Wildlife Trust reserve.
A secondary- aim of the study was to evaluate the 11land-use 11 hypothesis (eg.
Rosenqvist 1977, 1978, 1981) as a mechanism for lake acidification by examining high
altitude sites with no active land-management. Sites selected are all remote, lie above the
tree line and have undisturbed catchments.
Lochnagar and the Caimgorms are situated on sensitive granite geology (Kinniburgh
and Edmunds 1986, Wells et al. 1986) in an area of moderate acid deposition (c. 0.95 g S
yr-1
). It can be predicted that sensitive lakes in this area (those having Ca2
+ values of <60
μeq i-1
) will have acidified (Battarbee 1989)
Holocene climate variability in Europe and Africa: a PAGES PEP III time-stream 1 synthesis
No full text
Decadal and century-scale climate variability in tropical Africa during the past 2000 years
No full textDiatom 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
No full textEighty-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
Recovery of Lakes and Streams in the UK from Acid Rain. The United Kingdom Acid Waters Monitoring Network 20 year Interpretative Report
No full textPaleoecological and documentary records of recent changes in Garaet el Ichkeul: a seasonally saline lake in NW Tunisia
No full textPalaeoecological evidence for the timing and causes of lake acidification in Galloway, South West Scotland
No full textDuring the contract period sediment cores from six lakes, three with
non-afforested and three with partially afforested catchments, were
analysed to enable lake water acidity (pH) to be reconstructed over
approximately the past 200 years. The sites are all situated on granitic
rocks in the Galloway Hills of S.W. Scotland. The results of diatom
analysis show that five of the six lakes have become considerably more
acid over this time period and that the acidification process is mainly
independent of catchment afforestation effects. {210}^Pb dating of the
sediment shows that there has been little change in sediment accumulation
rates at sites with non-afforested catchments, but there has been significant increases in accumulation rate at afforested sites associated with
erosion caused by pre-planting catchment ploughing. Pollen analysis
indicates that no major vegetation change has occurred at the non-afforested
sites whilst trace metal analysis of L. Enoch (not funded by this contract)
shows elevated levels of Pb, Cu, and Zn 1n the upper, post 1800 sediments.
It is concluded that acid precipitation is the most likely cause of
acidification at these sites
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