Carbon storage in coastal reed (Phragmites australis) ecosystems

Distribution of the common reed (Phragmites australis) has increased in coastal ecosystems across the globe. Currently, there appears to be a gap in knowledge about carbon (C) cycling and sequestration in reed beds though preliminary findings indicate these systems are unique, show great potential for C storage, and, therefore, should be taken into consideration while developing blue carbon (BC) budgets. The aim of my study is to quantify how much C is stored in reed bed biomass and sediment along the brackish Pojo Bay system in coastal Finland. We selected 6 reed beds to sample along Pojo Bay covering a range of salinities and wave exposure from the northern-most part of the Bay to the southern-most part opening into the Baltic Sea. Within each reed bed, samples were taken from randomly selected sites within each of the 3 reed bed zones (terrestrial, intermittent, and littoral) and replicate samples were taken within each zone along a transect. Plant and sediment samples were collected and taken back to the lab to run for C content.  

My results from sediment LOI (loss of ignition) show higher organic matter content in the upper segments of sediment profiles and a general trend towards higher organic matter content in terrestrial and intermittent zones than littoral zones of reed beds. Preliminary results for C content within sediment and biomass samples show similar trends. These findings are significant as they help rectify a gap in knowledge and provide us with an estimate of how much C is stored in reed bed biomass and sediment. Information on how much C is stored within this rapidly expanding coastal ecosystem type is important for the management of reed beds and greatly impacts calculations for coastal carbon budgets to combat climate change. Further information will be gathered from these field sites every 3 months for 2 years to show seasonal variability in the C storage, C isotope analysis, and methane emissions to get a more comprehensive picture of C cycling in these important coastal ecosystems reed bed systems.