A PhD Marjolijn
PhD thesis onlinePhD Research Marjolijn (2007-2012):
Interactive Effects on Seagrass Ecosystems
Marjolijn’s PhD explored the interactions between eutrophication, grazing, and hydrodynamics in tropical seagrass ecosystems in Indonesia (Derawan Archipelago), a global hotspot for green turtles.
Sampling seagrass to look at possible effects of sedimentation & eutrophication of the Berau river (blog) 
Cage experiment on the interactive effect of grazing & nutrient addition
Eutrophication, Grazing & Resilience:
Exclosure experiments revealed that moderate turtle grazing enhances seagrass resilience to nutrient loading by stimulating growth and nutrient uptake.
Habitat Collapse in Marine Protected Areas:
We documented seagrass degradation in MPAs due to overgrazing by protected turtle populations, highlighting the need for integrated species-habitat management.
Coastal Protection Services:
Field experiments showed that grazed seagrass meadows stabilize sediments and reduce beach erosion.
Toxicity:
Lab studies demonstrated how light reduction and nutrient toxicity jointly affect seagrass health, informing management strategies.
Sea Turtle Population Studies:
We conducted baseline surveys and genetic studies to understand green turtle population dynamics and their impacts on seagrass ecosystems.
Impact of Grazing on Seagrass Fauna:
We compared seagrass-associated fauna in heavily grazed vs. less impacted areas to assess the broader ecological effects of turtle grazing.
Laboratory experiment on ammonia toxicity in tropical seagrasses Analyse the 1000’s of samples in Nijmegen
Restoring Fen Water Bodies: Effects on Aquatic Macroinvertebrates (2006)
