TABLE OF CONTENTS I. Legislative Requirements 1 II. Research to Date 2 III. Research Findings 3 IV. Peer Review 5 V. Proposed Research - Year Three 6 VI. Proposed Research - Year Four 6 I. Appendix I. Appendix II. Appendix III. Appendix IV. Studies of Hvdrothermal Processes in Crater Lake, A Report of Field Studies Conducted in 1988 for the National Park Service. Studies of Hvdrothermal Processes in Crater Lake, A proposal for a third year of research conducted for the National Park Service through the CPSU, Oregon State University. Peer Review of Research Program and Recommendations for Additional Investigations of Possible Hydrothermal Activity. Responses to the List of Recommendations from the Peer Review Panel on the Proposed Research, July, 1989. Studies of Hydrothermal Processes in Crater Lake A report of field studies conducted in 1988 for the National Park Service TABLE OF CONTENTS Introduction 1 Methods General 2 Bathymetry 4 Submersible operations 4 Navigation 4 Submersible sampling and photography 7 Water temperature and conductivity 10 Water samples 11 Chemical analyses 11 Sediment and crust analyses 13 Acknowledgements 13 Technical Findings The distribution of temperature and salt General temperature and density structure 14 Deep lake distributions 16 Near-bottom observations with the submersible 19 The chemistry of Crater Lake waters Introduction 24 Distribution with depth 24 Ion-ion systematics 27 Helium data 30 Radon-222 and Radium-226 34 Compositions of bacterial mat fluids 35 Geochemical mass balances 37 Bacterial mats Description and location 42 Electron microscopy and composition 46 Summary 52 Sediment and precipitate observations Descriptions and locations 52 Compositions of precipitates and crusts 53 Origin of mats and crusts 57 Geological Observations 5 8 Discussion and Conclusions Important hypotheses Hydrothermal springs 60 Conductive heat 62 Cold springs 62 Volatile Input 62 Precipitation from cold springs 63 Weathering of volcanic ash 64 Evaporation 64 Early fumarolic inputs 65 Summary 65 References 67 Appendices Appendix I, Summary of USGS dive results 72 Appendix II, Deep Water Plants and Animals in Crater Lake 74 Appendix III, Acoustic navigation 75 Appendix IV, Water chemistry data 77 TABLE OF CONTENTS I. Introduction 1 The Review Process ? ?.. ? 1 II. Crater Lake Overview 3 Limnology 3 Geophysics 4 Thermal Model ing 4 Geology 6 Geochemi stry 7 Microbiology 8 III. List of Recommendations for Additional Research Work at Crater Lake to Resolve the Hydrothermal Vent Issue 9 General Considerations 9 Lake Mixing Investigations 9 Water Column Physico-Chenrical Investigations 9 3He and 222Rn Isotope Investigations 10 Sediment Physico-Chemical and Hydrology Investigations ..?..,. 10 Bacteriological Investigations 10 Geological Investigations 11 IV. References 12 APPENDIX: J. Dymond and R.W. Collier- Treatment of Hypothesis, Question and Problem, and Proposed Studies.