Above ground blue carbon sequestration capacity of Sungai Pulai estuary seagrass meadows - a satellite based method

Abstract

Monitoring blue carbon (C) sequestration potential within coastal ecosystem is essential for enhancing climate change mitigation initiatives. Although remote sensing is known as a useful method for mapping benthic habitat and monitoring changes at large spatial scale compared to field survey methods, it has not been attempted for quantifying seagrass C stock. A satellite-based mapping approach, applied on Landsat imagery (acquired in 2004, 2009 and 2013) and field biomass data obtained from previous studies were used for repeat mapping of above ground seagrass C for the turbid water of the Sungai Pulai estuary, Johor Straits, Malaysia. The mapping approach has demonstrated (1) the ability to determine total above ground seagrass C sequestration capacity and identify the areas of highest C stock cover class from the spatially extensive biomass map, and (2) the spatio-temporal dynamics of seagrass C stocks that can be used to assess and monitor C fluxes and (3) informing costal managers to decide which data to be used and method to apply for monitoring climate change related activities when project demands a spatially explicit maps. According to the estimates, the highest mean C stock was in 2004 (90.68 kg C/pixel) and the lowest in 2013 (18.77 kg C/pixel) - a declining trend of seagrass cover, biomass and C stocks in the Sungai Pulai estuary. Further studies on the Sungai Pulai estuary should be conducted to identify C pools and to estimate total C stocks and fluxes in seagrass ecosystem.