ISSN 1366- 7300 UCL ENVIRONMENTAL CHANGE RESEARCH CENTRE University College London RESEARCH REPORT No. 37 Nutrient Reconstructions in Standing Waters: Final Report. H. Bennion, D.T. Monteith & P.G. Appleby A Report to English Nature by Ensis Ltd. on Contract No. FS0-11-02 July 1997 Environmental Change Research Centre University College London. 26 Bedford Way London WClH0AP Executive Summary 1. This is the final report to English Nature by ENSIS Ltd under contract F80-11-02: Nutrient Reconstructions in Standing Waters. 2. This project aims to employ palaeolimnological methods to determine a series of lakes which have remained largely unchanged since the 1920/30s, representing a trophic series in a near natural condition. The aim is to use these as model lakes to provide restoration targets for polluted waters. 3. This report describes the current macrophyte flora and water chemistry of thirteen lakes of conservation interest, and the lithostratigraphy, radiometric dating and fossil diatom assemblages in approximately four levels of a sediment core from the deep basin of each lake. 4. The palaeolimnological technique of diatom transfer functions is used to investigate the onset, rate, extent and possible causes of eutrophication at the study lakes. A diatom-based transfer function is applied to the fossil diatom data to generate a quantitative reconstruction of total phosphorus (TP) concentrations for each lake, following taxonomic harmonization between the model training set and the core species data. The TP reconstruction is calculated using a Northwest European training set of 152 lakes (Bennion et al., 1996). 5. In addition, quantitative reconstructions of lake pH were carried out for four sites. These were Wastwater, Oak Mere, Clarepool Moss and Hatchet Pond. pH reconstructions were carried out at these lakes because they were the only sites considered to be sensitive to surface water acidification. The pH reconstructions were calculated using the Surface Water Acidification Programme (SW AP) calibration set of 167 lakes from the UK and Scandinavia (Stevenson et al., 1991). The reconstructions were performed for four approximate points in time: 1850, 1900, 1920/30 and the present day. List of Contributors Appleby, P. G. Environmental Radioactivity Research Centre, University of Liverpool. Bennion, H. Environmental Change Research Centre, University College London. Monteith, D.T. Environmental Change Research Centre, University College London. Table of Contents EXECUTIVE SUMMARY LIST OF CONTRIBUTORS TABLE OF CONTENTS LIST OF TABLES LIST OF FIGURES APPENDIX 1. STUDY RATIONALE AND OBJECTIVES 1 2. SITE SELECTION AND REPORT STRUCTURE 2 3. METHODS 4 3.1 Macrophyte Surveys 4 3.2 Coring and Lithostratigraphic Analyses 5 3.3 Radiometric Dating 5 3.4 Diatom Analysis and Transfer Functions 6 4. CLAREPOOL MOSS, SHROPSHIRE (SJ 435 343) 10 4.1 Site Description and Water Chemistry 10 4.2 Macrophyte Survey 11 4.3 Lithostratigraphy 11 4.4 Radiometric Dating 11 4.5 Diatom Stratigraphy 11 4.6 Total Phosphorus and pH Reconstructions 12 4.7 Discussion 12 5. WASTWATER, CUMBRIA (NY 165 060) 19 5.1 Site Description and Water Chemistry 19 5.2 Macrophyte Survey 20 5.3 Lithostratigraphy 21 5.4 Radiometric Dating 21 5.5 Diatom Stratigraphy 22 5.6 Total Phosphorus and pH Reconstructions 22 5.7 Discussion 23 6. OAK MERE, CHESHIRE (SJ 574 677) 32 6.1 Site Description and Water Chemistry 32 6.2 Macrophyte Survey 33 6.3 Lithostratigraphy 34 6.4 Radiometric Dating 34 6.5 Diatom Stratigraphy 34 6.6 Total Phosphorus and pH Reconstructions 35 6.7 Discussion 35 7. BASSENTHWAITE LAKE, CUMBRIA (NY 214 296) 43 7.1 Site Description and Water Chemistry 43 7.2 Macrophyte Survey 44 7.3 Lithostratigraphy 46 7.4 Radiometric Dating 47 7.5 Diatom Stratigraphy 48 7.6 Total Phosphorus Reconstruction 49 7.7 Discussion 49 8. GREENLEE LOUGH, NORTHUMBRIA (NY 774 698) 60 8.1 Site Description and Water Chemistry 60 8.2 Macrophyte Survey 61 8.3 Lithostratigraphy 62 8.4 Radiometric Dating 63 8.5 Diatom Stratigraphy 63 8.6 Total Phosphorus Reconstruction 64 8.7 Discussion 64 9. HATCHET POND, HAMPSHIRE (SU 367 016) 71 9.1 Site Description and Water Chemistry 71 9.2 Macrophyte Survey 72 9.3 Lithostratigraphy 73 9.4 Radiometric Dating 74 9.5 Diatom Stratigraphy 74 9.6 Total Phosphorus and pH Reconstructions 75 9.7 Discussion 75 10. SEMERWATER, NORTH YORKSHIRE (SD 918 874) 83 10.1 Site Description and Water Chemistry 83 10.2 Macrophyte Survey 84 10.3 Lithostratigraphy 85 10.4 Radiometric Dating 85 10.5 Diatom Stratigraphy 86 10.6 Total Phosphorus Reconstruction 87 10.7 Discussion 87 11. BETTON POOL, SHROPSHIRE (SJ 509 078) 96 11.1 Site Description and Water Chemistry 96 11.2 Macrophyte Survey 97 11.3 Lithostratigraphy 97 11.4 Radiometric Dating 97 11.5 Diatom Stratigraphy 98 11.6 Total Phosphorus Reconstruction 98 11.7 Discussion 99 12. UPTON BROAD, NORFOLK (TG 388134) 106 12.1 Site Description and Water Chemistry 106 12.2 Macrophyte Survey 107 12.3 Lithostrntigraphy 108 12.4 Radiometric Dating 108 12.5 Diatom Stratigraphy 109 12.6 Total Phosphorus Reconstruction 110 12.7 Discussion 110 13. MARTHAM SOUTH BROAD, NORFOLK (TG 458 201) 119 13.1 Site Description and Water Chemistry 119 13.2 Macrophyte Survey 120 13.3 Lithostratigraphy 121 13.4 Radiometric Dating 121 13.5 Diatom Stratigraphy 122 13.6 Total Phosphorus Reconstruction 122 13.7 Discussion 122 14. ESTHWAITE WATER, CUMBRIA (SD 358 969) 130 14.1 Site Description and Water Chemistry 130 14.2 Macrophyte Survey 131 14.3 Lithostrntigraphy 133 14.4 Radiometric Dating 133 14.5 Diatom Stratigraphy 134 14.6 Total Phosphorus Reconstruction 135 14.7 Discussion 135 15. CROSE MERE, SHROPSHIRE (SJ 430 305) 145 15.1 Site Description and Water Chemistry 145 15.2 Macrophyte Survey 146 15.3 Lithostratigraphy 147 15.4 Radiometric Dating 147 15.5 Diatom Stratigraphy 149 15.6 Total Phosphorus Reconstruction 150 15.7 Discussion 150 16. MALHAM TARN, NORTH YORKSHIRE (SD 894 668) 159 16.1 Site Description and Water Chemistry 159 16.2 Macrophyte Survey 160 16.3 Lithostratigraphy 161 16.4 Radiometric Dating 161 16.5 Diatom Stratigraphy 162 16.6 Total Phosphorus Reconstruction 163 16.7 Discussion 163 17. OVERALL DISCUSSION AND SUMMARY 172 17.1 Lake Conservation and Classification 172 17.2 Lake Conservation and Palaeolimnology 174 17.3 Summary of Findings 175 18. ACKNOWLEDGEMENTS 180 19. REFERENCES 181 list of Tables Table 1 The selected study sites with lake type and grid references 2 Table 2 Species list and DAFOR abundance rating for Wastwater 21 Table 3 Chronology of Wastwater 22 Table 4 Species list and DAFOR abundance rating for Oak Mere 33 Table 5 Species list and DAFOR abundance rating for Bassenthwaite Lake 46 Table 6 Chronology of Bassenthwaite Lake 48 Table 7 Species list and DAFOR abundance rating for Greenlee Lough 62 Table 8 Species list and DAFOR abundance rating for Hatchet Pond 73 Table 9 Chronology for Hatchet Pond 74 Table 10 Species list and DAFOR abundance rating for Semerwater 85 Table 11 Chronology of Semerwater 86 Table 12 Chronology of Betton Pool 98 Table 13 Species abundance and DAFOR abundance rating for Upton Broad 108 Table 14 Chronology of Upton Broad 109 Table 15 Species list and DAFOR abundance rating for Martham South Broad 121 Table 16 Species list and DAFOR abundance rating for Esthwaite Water 132 Table 17 Chronology of Esthwaite Water 134 Table 18 Species list and DAFOR abundance rating for Crose Mere 147 Table 19 Chronology of Crose Mere 149 Table 20 Species list and DAFOR abundance rating for Malham Tarn 161 Table 21 Chronology of Malham Tarn 162 Table 22 OECD trophic classification scheme (OECD, 1982) 172 Table 23 UKA WRG surface water classification scheme (UKA WRG, 1989) 173 Table 24 Summary table of environmental change as inferred by diatoms and macrophytes 179 List of Figures Figure 1 Lithostratigraphic data for elarepool Moss 14 Figure 2 210Pb Activity versus Depth - eiarepool Moss 15 Figure 3 mes Activity versus Depth - elarepool Moss 16 Figure 4 Summary diatom diagram and reconstructions for elarepool Moss 17 Figure 5 Aquatic macrophyte distribution map for W astwater 24 Figure 6 Aquatic macrophyte transect profile for W astwater 25 Figure 7 Lithostratigraphic data for W astwater 26 Figure 8 210 Pb Activity versus Depth - Wastwater 27 Figure 9 mes and 241 Am Activity versus Depth - Wastwater 28 Figure 10 Depth versus Age - Wastwater 29 Figure 11 Summary diatom diagram and reconstructions for W astwater 30 Figure 12 Aquatic macrophyte distribution map for Oak Mere 37 Figure 13 Lithostratigraphic data for Oak Mere 38 Figure 14 210Pb Activity versus Depth - Oak Mere 39 Figure 15 mes Activity versus Depth - Oak Mere 40 Figure 16 Summary diatom diagram and reconstructions for Oak Mere 41 Figure 17 Aquatic macrophyte distribution map for Bassenthwaite Lake North 50 Figure 18 Aquatic macrophyte distribution map for Bassenthwaite Lake South 51 Figure 19 Aquatic macrophyte distribution map for Bowness Bay, Bassenthwaite Lake 52 Figure 20 Aquatic macrophyte transect profiles for Bassenthwaite Lake 53 Figure 21 Lithostratigraphic data for Bassenthwaite Lake 54 Figure 22 2 rnPbactivity versus Depth - Bassenthwaite Lake 55 Figure 23 mes and 241 Am Activity versus Depth - Bassenthwaite Lake 56 Figure 24 Depth versus Age - Bassenthwaite Lake 57 Figure 25 Summary diatom diagram and reconstruction for Bassenthwaite Lake 58 Figure 26 Aquatic macrophyte distribution map for Greenlee Lough 65 Figure 27 Lithostratigraphic data for Greenlee Lough 66 Figure 28 210Pb Activity versus Depth - Greenlee Lough 67 Figure 29 137es Activity