The K’ómoks and Squamish Estuaries: A Blue Carbon Pilot Project Final Report to North American Partnership for Environmental Community Action (NAPECA) Grant 2014-1362 Comox Valley Project Watershed Society Christine Hodgson, M.Sc. and Angela Spooner, M.Sc. April 2016 1 Table of Contents Executive Summary.............................................................................................................................................. 5 Mapping Eelgrass & Saltmarsh .................................................................................................................... 5 Estimating Carbon Stores & Sequestration Rates ................................................................................ 5 Our Results .......................................................................................................................................................... 5 Eelgrass & Saltmarsh Habitat Restoration .............................................................................................. 6 Opportunity for other Coastal Communities ......................................................................................... 6 Chapter 1 - Introduction ..................................................................................................................................... 7 Blue Carbon ......................................................................................................................................................... 7 Comox Valley Project Watershed ............................................................................................................... 7 The Project .......................................................................................................................................................... 8 Our Results .......................................................................................................................................................... 8 Chapter 2 - NAPECA Study Sites ...................................................................................................................... 9 Location of Study Sites................................................................................................................................. 11 Chapter 3 - Mapping Eelgrass and Saltmarsh Habitats ....................................................................... 13 Interpreting Digital Air Photos for Eelgrass Coverage .................................................................... 13 Using GPS Tracks to Verify Air Photo Interpretation ...................................................................... 16 Mapping Saltmarsh Coverage using Air Photos ................................................................................. 17 Mapping Subtidal Eelgrass ......................................................................................................................... 17 Using GPS Tracks to Map Eelgrass .......................................................................................................... 20 How to Collect Mapping Data using a Handheld GPS Unit ............................................................. 21 How to Transfer GPS data to Google Maps .......................................................................................... 22 Chapter 4 - Methods for Carbon Sequestration in Aquatic Sediments - Literature Review . 25 Introduction ..................................................................................................................................................... 25 Background ...................................................................................................................................................... 26 Role of Coastal Ecosystems in Mitigating Global Climate Change ......................................... 26 Carbon Stores in Aquatic Habitats ..................................................................................................... 27 Seagrass Meadows in British Columbia ........................................................................................... 28 Emergent Tidal Marshes in British Columbia ..................................................................................... 30 Carbon Storage Capability ..................................................................................................................... 32 Methods for Estimating Carbon Sequestration .................................................................................. 32 a) Estimation of sediment accumulation rate ............................................................................... 33 2 b) Collecting and Handling Sediment Samples ............................................................................. 34 c) Estimation of Soil Carbon Content ................................................................................................ 35 Literature Cited .............................................................................................................................................. 37 Chapter 5 - Collecting Sediment Cores ...................................................................................................... 41 Equipment Required for Collecting Sediment Cores ....................................................................... 41 Constructing a Coring Stand ...................................................................................................................... 43 Collecting Sediment Cores .......................................................................................................................... 45 Sectioning a Sediment Core ....................................................................................................................... 46 Chapter 6 - Sediment Collection & Analyses Methodology ................................................................ 50 Sediment Cores and Subsurface Samples ............................................................................................. 50 Analysis of Samples ...................................................................................................................................... 52 Analytical Methods ........................................................................................................................................ 52 Radioisotope analysis ............................................................................................................................. 52 Organic carbon and total nitrogen ..................................................................................................... 52 Stable isotope analysis ........................................................................................................................... 53 Sediment Mixing Layer ................................................................................................................................ 53 Calculation of Sedimentation Rate .......................................................................................................... 53 C: N Ratio as an Organic Matter Source Indicator ............................................................................. 54 Stable Isotopes ................................................................................................................................................ 54 Calculation of Carbon Sequestration Rate ........................................................................................... 55 References ........................................................................................................................................................ 55 Chapter 7 - Results of Sediment Analyses ................................................................................................ 58 Sediment Core Measures ............................................................................................................................ 58 Sediment Velocity .......................................................................................................................................... 58 Sediment Accumulation Rate .................................................................................................................... 64 Sediment SML Depth .................................................................................................................................... 64 Organic Carbon and Nitrogen ................................................................................................................... 64 Carbon Burial Percent ............................................................................................................................ 64 Corg Sources ................................................................................................................................................. 67 Carbon Accumulation and Stored Carbon ............................................................................................ 69 Discussion ......................................................................................................................................................... 70 References ........................................................................................................................................................ 71 3 Chapter 8 - Eelgrass Transplant Methods ................................................................................................ 73 Identify Transplant & Donor Sites .........................................................................................................