|Blue carbon storage in salt marshes and tidal flats|
Geertsma, R. (2021). Blue carbon storage in salt marshes and tidal flats. BSc Thesis. NIOZ Royal Netherlands Institute for Sea Research: Yerseke. 44 pp.
The internship thesis is written in accordance with NIOZ (Royal Netherlands Institute of Sea Research), NIOZ is interested in the blue carbon storage in salt marshes and tidal flats in the Westerschelde and the Oosterschelde. According to recent findings, net removal of anthropogenic CO2 from the atmosphere may be necessary to reverse undesirable climate changes on timescales relevant to human civilisation. Vegetated coastal ecosystems mitigate anthropogenic CO2 by storing carbon, this stored carbon is called blue carbon (BC) (Tamis & Foekema, 2015). However, blue carbon is still a relatively unknown subject. Here we show the contribution of environmental characteristics on blue carbon storage and the short-term and long-term sediment variability of salt marshes and tidal flats. We found that the environmental characteristics salinity, oxygenation and allochthonous and autochthonous sediment play an important role in the sedimentation process. Each factor influences the degradation rate of labile organic carbon (LOC) and refractory organic carbon (ROC) which has a negative effect on sedimentation, thereby influencing the sediment variability per location. Furthermore, we found that less resuspension happens in sheltered locations resulting in lower sediment dynamics than exposed locations. Our results show that the decrease in sediment supply or low sediment variability causes for salt marshes to not be able to grow fast enough to keep up with the sea level rise, resulting in regressive succession or drowning of the salt marshes. We anticipate our assay to be a starting point for more research to blue carbon storage, where it is recommended to focus on the sustainability of tidal flats.