The use of diatom records to establish reference conditions for UK lakes subject to eutrophication

A knowledge of pre-disturbance conditions is important for setting realistic restoration targets for lakes. For European waters this is now a requirement of the European Council Water Framework Directive where ecological status must be assessed based on the degree to which present day conditions deviate from reference conditions. Here, we employ palaeolimnological techniques, principally inferences of total phosphorus from diatom assemblages (DI-TP) and classification of diatom composition data from the time slice in sediment cores dated to similar to 1850 AD, to define chemical and ecological reference conditions, respectively, for a range of UK lake types. The DI-TP results from 169 sites indicate that reference TP values for low alkalinity lakes are typically 3 m mean depth) generally had lower reference TP concentrations than the shallow sites. A small group of shallow marl lakes had concentrations of similar to 30 mu g L-1. Cluster analysis of diatom composition data from 106 lakes where the key pressure of interest was eutrophication identified three clusters, each associated with particular lake types, suggesting that the typology has ecological relevance, although poor cross matching of the diatom groups and the lake typology at type boundaries highlights the value of a site-specific approach to defining reference conditions. Finally the floristic difference between the reference and present day (surface sample) diatom assemblages of each site was estimated using the squared chord distance dissimilarity coefficient. Only 25 of the 106 lakes experienced insignificant change and the findings indicate that eutrophication has impacted all lake types with > 50% of sites exhibiting significant floristic change. The study illustrates the role of the sediment record in determining both chemical and ecological reference conditions, and assessing deviation from the latter. Whilst restoration targets may require modification in the future to account for climate induced alterations, the long temporal perspective offered by palaeolimnology ensures that such changes are assessed against a sound baseline

Historical changes (1905-2005) in external phosphorus loads to Loch Leven, Scotland, UK

This article reviews historical changes in the total phosphorus (TP) inputs to Loch Leven, Scotland, UK. Data derived from palaeolimnological records suggest that inputs in the early 1900s were about 6 t TP year-1 (0.45 g TP m-2 year-1). By 1985, this had risen to about 20 t TP year-1 (1.5 g TP m-2 year-1) due to increases in runoff from agricultural land and discharges from point sources. By the late 1970s, increased TP inputs were causing serious degradation of lake water quality. Most noticeably, there had been an increase in cyanobacterial blooms. A catchment management plan was implemented in the early 1990s. This resulted in a 60% reduction in the annual TP input between 1985 (20 t TP year-1/1.5 g TP m-2 year-1) and 1995 (8 t TP year-1/0.6 g TP m-2 year-1). The main reduction was associated with better control of point source discharges, but attempts were also made to reduce inputs from diffuse sources. The reduction in external TP loading to the lake led to a marked decline in TP retention by the lake each year

Practice in Skills Designed to Improve Ability in Playing Handball

Practice sessions in the skill described in this paper were carried on by the writer during the months of January and February, 1939. The object of the practice sessions was to develop skill in handball, in which the subject had had no previous experience. Before deciding on the method of procedure, the subject observed several expert players. He then decided to practice along three lines which seemed most important in securing proficiency in the game

Palaeoecological study of Loch Ussie

Loch Ussie is a relatively shallow, mesotrophic loch located near Dingwall in the Scottish Highlands which has been designated as a Site of Special Scientific Interest (SSSI) and a Special Area of Conservation for its freshwater habitat, particularly its diverse submerged macrophyte flora. There are increasing concerns about water quality with at least one major algal bloom occurring in recent years and the apparent loss of Pillularia globulifera, a notified interest in the SSSI. Catchment management plans are being drafted that will consider incentives to reduce nutrient input from the agricultural areas of the catchment and proposals to manage loch water levels. In order to inform these plans, information about past nutrient conditions in the loch is desirable. This project aimed to build on an earlier palaeolimnological study of diatom assemblages in a sediment core from the loch to fully assess the magnitude and trends in water quality change at Loch Ussie over the last 150 years, and particularly over the last two or three decades. This report examines diatoms in an additional 10 samples from an archived sediment core, USSI1, and involves application of a diatom transfer function to infer past total phosphorus concentrations in the loch

Palaeoecological study of Linlithgow Loch, Scotland

1. Collect an open water and a littoral core from the loch 2. Extrude the cores in the field at 1 cm intervals 3. Describe the cores 4. Measure dry weight and organic matter content of selected levels of the two cores 5. Analyse spheroidal carbonaceous particles in 20 samples of the open water cores to establish sedimentation rates and approximate the chronology. Correlate the open water and littoral cores to provide an approximate chronology for the latter. 6. Analyse diatom assemblages in five samples from selected depths of the open water core 7. Analyse plant macrofossils in five samples from selected depths of the littoral core 8. Produce a summary report of the findings (August 2006)

Assessing reference conditions and ecological status for lakes using subfossil diatoms

This is the final report to the Environment Agency under an extension to the project, ‘Development of a phytobenthos classification tool for lakes and lochs of UK (DALES– Diatom Assessment of lake and loch ecological status)’ (contract no. SC030103), funded by the Environment Agency (EA).This project forms part of the strategy for the implementation of the European Council Water Framework Directive (WFD), which requires reference conditions to be determined for all water body types including lakes