In my PhD project I look at processes that influence vegetation establishment on salt marshes. This research is embedded within the Mud Motor project, that looks at opportunity to re-use harbour dredge disposal beneficially to enlarge salt marsh areas and both its ecological and physical consequences. Salt marshes protect the coastline by their wave attenuation, a nature-based flood protection, in addition to being a vital area for many unique floral and faunal species. The potential for marsh expansion lies at the outer edges of the marsh, the transition zone from marsh to intertidal flats. This is a dynamic area affected by (among other variables) salt stress and occasionally extreme dry conditions, frequent tidal submergence, and deposition and erosion of sediment.
Specifically, I look at the interactions between bioturbating soil fauna, vegetation establishment and sediment dynamics, using lab and mostly field experiments. Bioturbation by worms can bury seeds and cause freshly sprouted seedlings to tumble, thereby reducing vegetation establishment. Erosion may deplete the seedbank and transport viable seeds away from the transition zone. Sedimentation can lead to seed retention but also has the potential smother seedlings or bury seeds too deep for surfacing once germinated. Spatial and temporal patterns of seed availability, weather conditions and sediment dynamics are in constant interplay that determines salt marsh reduction or expansion.
By: Fokje Schaafsma en Marin van Regteren, Wageningen Marine Research On our way south In Fremantle, Australia, we join the Japanese research vessel Kaiyo Maru on December 4th. Before we leave, we have some time to look around the city and buy some last supplies. Usually, we unpack our boxes…
Day 3. Counting fish We are ready to start diving with our group of eight scientists plus dive instructor Kirstin. At the diving deck we are queuing up with our regulators and fins in hand. Then the captain gives a sign and we jump into the water at a rapid…
