Beginning:      March/April 2020 – September/October 2020
Duration:        6 months, unpaid
Credits:           up to 45 ECTS depending on duration


Future climatic scenarios point to a threat of salinization in protected Dutch floating fen ecosystems. This is mainly caused by an increased upward seepage of saline groundwater and an increased inflow of saline surface water. The term floating fen already reveals that the root mat of this ecosystem floats on top of that surface water. In The Netherlands you find them for instance in old turf extraction sites. Here plants grew horizontally into turf ponds, meaning that they are usually still attached to the non-floating baulks. This leads to a zonation in species composition and water quality from the root mat edge into a system that is characterized more by fen meadow plant species. Both these plant communities are mainly made up of salt sensitive plant species, some of which are even red-listed. So we want to understand what the relationship is between surface water salt concentrations and plant response. Do we actually find an increase or built up of salts in the rhizosphere? Which abiotic factors cause a change in micro- and macronutrients in the floating fen root zone? And how do plant species respond to that? Or, what happens if plant species tap directly into brackish surface water?


During this project you can join the field campaign that started in August 2019. We have installed a setup of micro- and macrorhizons in the protected nature area Botshol (25min drive from Amsterdam). Surface water concentration in summer reaches 1100±100 mgCl/L, which is actually very brackish. Through the collection of bi-weekly soil pore water from various distances from the water’s edge and multiple depths we can monitor how the salt water is intruding into the root mat. You will analyze these samples using methods available at the Vrije Universiteit. If you are interested it is possible to build in a component of vegetation monitoring and mapping.

Important note: The field locations are only accessible by kayak or canoe. If needed – in some cases – you will be able to loan a small motor boat. A lab car to reach the field site is available at our university. Boats are available at the field site.


Driver’s license is pre. Interest in field work is required. Enthusiasm for Dutch flora and vegetation mapping will be positively received.

Contact information

Milou Huizinga is a PhD student working on salinization of natural floating fen plant communities in the Netherlands. During her PhD project she is supervised by Prof. Dr. Ing. Flip Witte and Prof. Dr. Rien Aerts.

If this topic appeals to you, please email
Faculty of Science, VU Amsterdam.
Dept. of Ecological Science, subdept. Systems Ecology, room A-159.
Address: De Boelelaan 1085, 1081 HV Amsterdam