Blog entry by Floris Keizer - Junior Lecturer / Researcher

I think we should honor the ecosystem services of natural wetland systems more. One of the ecosystem services we want to get a grip on is the natural nutrient retention function of floodplains. Mostly, nutrients in flood water are only measured as dissolved fraction. However, a substantial part of the nutrients is transported as particulate nutrients (organic matter) or bound to suspended sediment and this is what we study.

We use the natural Biebrza river valley (Poland) with annual snow-melt spring flood as study area. It has a fairly undisturbed character and there is a wealth of data available on surface and groundwater hydrology and vegetation.

April 2014: A promising reconnaissance survey
Last year during the spring flood we tested our new equipment: the Phillips sampler. Water flows through a small inlet tube and into a larger PVC cylinder. There, flow velocity drops and suspended sediment (with nutrients attached) is deposited. At the end, water exits the samplers through another small tube. The sediment can be collected and show cumulative suspended particulate nutrient transport over the period of submergence. To actually know how much is deposited on the floodplain, we installed artificial grass mats. Both techniques showed promising results so last October we up-scaled our experiment to more locations and higher spatial and temporal resolution.

Blog entry by Jiefei Mao - PhD candidate

If you are familiar with the water droplets on the green leaves or flower petals, have you seen or imaged when you put a droplet on the soil surface? Sometimes, the droplets do not immediately infiltrate into the soils, instead of that, they can stay several seconds, minutes even hours. This phenomenon is called ‘soil water repellency’ (SWR). Why is it worth doing research on this topic? The reason is that soil water repellency interrupts the water penetration, impacts the water uptake of plants and becomes a potential factor causing soil erosion. The hydrophobic soil organic matters derived from vegetation or microorganisms cause soil water repellency, we defined such components as ‘SWR-markers’. What are those SWR-markers and where do they come from?