Blue Carbon Audit of Orkney Waters Scottish Marine and Freshwater Science Vol 11 No 3
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Blue carbon audit of Orkney waters Scottish Marine and Freshwater Science Vol 11 No 3 J S Porter, W E N Austin, M T Burrows, D Clarke, G Davies, N Kamenos, S Riegel, C Smeaton, C Page and A Want Blue Carbon Audit of Orkney Waters Scottish Marine and Freshwater Series Vol 11 No 3 J S Porter, W E N Austin, M T Burrows, D Clarke, G Davies, N Kamenos, S Riegel, C Smeaton, C Page, A Want Published by Marine Scotland Science ISSN: 2043-7722 DOI: 10.7489/12262-1 Marine Scotland is the directorate of the Scottish Government responsible for the integrated management of Scotland’s seas. Marine Scotland Science (formerly Fisheries Research Services) provides expert scientific and technical advice on marine and fisheries issues. Scottish Marine and Freshwater Science is a series of reports that publishes results of research and monitoring carried out by Marine Scotland Science. It also publishes the results of marine and freshwater scientific work that has been carried out for Marine Scotland under external commission. These reports are not subject to formal external peer-review. This report presents the results of marine and freshwater scientific work carried out for Marine Scotland under external commission. This work is not a reflection of the opinion or policies of Scottish Ministers or the Scottish Government. © Crown copyright 2020 You may re-use this information (excluding logos and images) free of charge in any format or medium, under the terms of the Open Government Licence. To view this licence, visit: http://www.nationalarchives.gov.uk/doc/open-governmentlicence/ version/3/ or email: [email protected]. Where we have identified any third party copyright information you will need to obtain permission from the copyright holders concerned. Contents Executive Summary ................................................................................................... 3 1. Introduction ............................................................................................................ 5 1.1. Project Background ......................................................................................... 5 1.2. Terminology ..................................................................................................... 8 1.3. Project Objectives ............................................................................................ 9 2. Methodology ........................................................................................................... 9 2.1. Data review and blue carbon classification scheme ...................................... 10 2.2. Assessment of Spatial Extents of Habitats .................................................... 11 3. Habitat Identification: Biological Environments ..................................................... 12 3.1. Introduction .................................................................................................... 12 3.2. Biological Habitats ......................................................................................... 13 3.2.1. Kelp Forest .............................................................................................. 13 3.2.2. Maerl Beds .............................................................................................. 22 3.2.3. Seagrass Beds (Zostera) ........................................................................ 26 3.2.4. Saltmarshes ............................................................................................ 30 3.2.5. Horse Mussel (Modiolus modiolus) ......................................................... 33 3.2.6. Flame Shell (Limaria hians) ..................................................................... 39 3.2.7. Brittlestar Beds ........................................................................................ 43 3.2.8. Bryozoan Thicket .................................................................................... 47 4. Habitat Identification: Sedimentary Environments ................................................ 51 4.1. Introduction .................................................................................................... 51 4.2. Substrate Identification and Spatial Extent .................................................... 51 4.2.1. Sediment Type (Folk Classification) ........................................................ 52 Sediment Spatial Distribution ............................................................... 54 4.2.2. Sediment Thickness ................................................................................ 56 4.3. Geological Blue Carbon Values ..................................................................... 56 4.3.1. Data Availability And Quality ................................................................... 56 4.4. Calculations ................................................................................................... 59 4.4.1. Organic Carbon Stocks ........................................................................... 59 4.4.2. Inorganic Carbon Stocks ......................................................................... 59 4.4.3. Sedimentary C Density ........................................................................... 61 5. Blue Carbon Results of Orkney Waters ................................................................ 62 5.1. Carbon Audit Results ..................................................................................... 62 5.2. Uncertainty Analysis ...................................................................................... 65 6. Discussion of the Orkney Blue Carbon Audit ....................................................... 67 6.1. Blue Carbon Assessment across the Orkney Region .................................... 67 6.1.1. Carbon Standing Stocks.......................................................................... 67 6.1.2. Sequestration Rates ................................................................................ 67 6.1.3. Carbon Budgets: Production versus Sequestration ................................. 68 6.1.4. Current Blue Carbon Protection Measures.............................................. 68 6.2. Pressures on Blue Carbon Resources ........................................................... 68 6.2.1. Pressures on Carbon Stored In Sediment ............................................... 68 6.2.2. Pressures on Carbon Stored in Organisms ............................................. 69 6.2.3. Pressures Caused By Land Use Changes .............................................. 71 6.3. Knowledge gaps and priority research areas ................................................. 73 6.4. Availability of Accurate Geological Data ........................................................ 75 7. Conclusions .......................................................................................................... 75 7.1. Main Findings from the Work ......................................................................... 75 7.2. Pressures on the Resources ......................................................................... 76 7.2.1. Pressures on the Blue Carbon Resources .............................................. 76 7.2.2. Pressures on the Sequestration of the Blue Carbon Resources ............. 76 7.3. Knowledge Gaps and Recommendations for Future Work ............................ 77 8. References ........................................................................................................... 79 9. Acknowledgements .............................................................................................. 86 10. Appendices ........................................................................................................ 87 Appendix A Maxent Modelling Methodology ......................................................... 87 Appendix B Scottish Zostera Information .............................................................. 93 Appendix C Map of the Study Region with Key Place Names .............................. 95 Appendix D Unit Conversion ................................................................................. 96 Blue Carbon Audit of Orkney Waters J S Porter1, W E N Austin2, M T Burrows3, D Clarke4, G Davies4, N Kamenos5, S Riegel2, C Smeaton2, C Page4, A Want1,4 1 International Centre for Island Technology, Heriot Watt University Orkney Campus, Robert Rendall Building, Franklin Road, Stromness, Orkney, KW16 3AW 2 School of Geography & Sustainable Development, University of St Andrews, St Andrews, Fife, KY16 9AL 3 Scottish Association for Marine Science, Scottish Marine Institute, Oban, Argyll. PA37 1QA 4 Aquatera Ltd., Old Academy Business Centre, Stromness, Orkney, KW16 3AW 5 School of Geographical & Earth Sciences, University of Glasgow, Glasgow, G12 8QQ Keywords Blue carbon; inorganic carbon; organic carbon; storage; standing stocks. Background In this study, we provide an audit of the potential blue carbon resources present in the coastal waters around Orkney, bounded by the 12 nautical mile limit and including the Loch of Stenness brackish water lagoon. This report builds on previous work by Burrows et al. (2017) in which blue carbon stocks in Marine Protected Areas in Scottish waters were estimated from i) contributions of biological material to the fixation of carbon, also referred to as production, and ii) contributions of sediments to blue carbon storage. The methodology has been further developed here to allow regional-scale estimation of habitat extent and provides estimates of blue carbon