1 Freshwater macroalgae of Britain and Ireland with an introduction to their use in ecological assessment (RAPPER: Rapid Assessment of PeriPhyton Ecology in Rivers) Martyn Kelly1, Lydia King2, Chris Carter3, Jan Krokowski4, Phil Harding5 and Allan Pentecost6 1 Bowburn Consultancy, 11 Monteigne Drive, Bowburn, Durham DH6 5QB, UK; [email protected] 2 Basler Landstrasse 54, 79111 Freiburg, Germany. 3 6 Church View, Wootton, Northampton, NN4 7LJ, UK. 4 Scottish Environment Protection Agency, Parklands Avenue, Eurocentral, Holytown, North Lanarkshire ML1 4WQ. 5 Environment Agency, Scarrington Road,Westbridgeford,Nottingham NG2 5FA 6 Freshwater Biological Association, The Ferry Landing, Ambleside, Cumbria LA22 0LP. Version: 1.7 (April 2016) This is a working document and has been published in this format to facilitate testing of the method. If you have any comments or suggestions on how this document can be improved, please do get in touch and we will incorporate these into future versions of the text. Comments should be sent to [email protected] 2 CONTENTS Contents ..................................................................................................................................... 2 ACKNOWLEDGEMENTS ....................................................................................................... 4 1. Introduction ............................................................................................................................ 5 1.1 Defining and identifying freshwater “macroalgae” ......................................................... 5 1.2 Using macroalgae for rapid assessment ........................................................................... 6 1.3 Conceptual basis for RAPPER......................................................................................... 7 2. SURVEYING AND STUDYING MACROALGAE ............................................................ 9 2.1 Collecting, preserving and examining freshwater macroalgae ........................................ 9 2.2. Surveying macroalgae for ecological assessments ....................................................... 11 3. Identification of macroalgae: overview ............................................................................... 16 3.1 Introduction .................................................................................................................... 16 3.2. Preliminary identification ............................................................................................. 18 A. Crusts .............................................................................................................................. 19 B. Colonies ........................................................................................................................... 20 C. Mats, flocs and films ....................................................................................................... 21 D. Filaments ......................................................................................................................... 22 E. Other types of macroalgal growth form .......................................................................... 22 4. Cyanobacteria (blue-green algae) ........................................................................................ 24 4.1 Introduction .................................................................................................................... 24 Chrococcales ........................................................................................................................... 24 Synechococcales ...................................................................................................................... 24 Oscillatoriales .......................................................................................................................... 24 Pseudanabaenales ................................................................................................................... 25 Nostocales ................................................................................................................................ 25 4.2 How to identify Cyanobacteria ...................................................................................... 25 4.4 Descriptions of Cyanobacteria genera ........................................................................... 29 5. Chlorophyta and Xanthophyta ............................................................................................. 47 5.1 Introduction .................................................................................................................... 47 Tetrasporales ........................................................................................................................... 48 Volvocales ................................................................................................................................ 48 3 Sphaeropleales ........................................................................................................................ 48 Oedogoniales ........................................................................................................................... 48 Chaetophorales........................................................................................................................ 48 Microsporales .......................................................................................................................... 48 Ulotrichales ............................................................................................................................. 48 Klebsormidiales ....................................................................................................................... 48 Cladophorales.......................................................................................................................... 48 Prasiolales ............................................................................................................................... 49 Ulvales ..................................................................................................................................... 49 Zygnematales ........................................................................................................................... 49 5.2 How to identify filamentous Chlorophyta and Xanthophyta ......................................... 50 5.3 Keys to Chlorophyta and Xanthophyta .......................................................................... 52 5.4 Descriptions of Chlorophyta genera .............................................................................. 57 5.5 Descriptions of Charophyta genera ................................................................................ 79 5.6 Descriptions of Xanthophyta genera .............................................................................. 84 6. Rhodophyta .......................................................................................................................... 86 6.1 Introduction .................................................................................................................... 86 6.2 How to identify red algae found in freshwater benthic habitats ................................... 87 6.3 Key to common freshwater Rhodophyta ....................................................................... 87 6.4 Descriptions of Rhodophyta genera ............................................................................... 90 7. Other groups....................................................................................................................... 101 7.1. Diatoms (Bacillariophtya) ........................................................................................... 101 7.2 Chrysophyta ................................................................................................................. 106 7.3 Phaeophyta ................................................................................................................... 109 7.4. Other organisms .......................................................................................................... 111 8. Interpretation ...................................................................................................................... 114 8.1 Introduction .................................................................................................................. 114 8.2 Application of RAPPER to survey results ................................................................... 114 7. Glossary ............................................................................................................................. 117 9. REFERENCES .................................................................................................................. 120 Appendix A. RAPPER Survey Sheet ................................................................................... 127 4 ACKNOWLEDGEMENTS The first version of this guide (by MK and LK) was produced for a training course organised in Ireland for the North-South Share project, funded by the INTERREG IIIA programme for Ireland / Northern Ireland. Participants on this and subsequent training courses made many useful comments that we incorporated into this version. We are grateful to the Scottish Environment Protection Agency for funding the development of RAPPER. All illustrations, unless otherwise acknowledged, by Chris Carter (CFC), Lydia King