"I measured phosphorus levels at prominent locations in the Western Scheldt using a colorimetric method and took photograms of the last resilient eels from the Scheldt. I also filmed the mystical fluorescence of algae and microplastics in the old dry docks of the former port of Antwerp.

Due to a lack of renaturation areas, the strong tidal influence, as well as the deepening of channels and polder management, there is a serious decline of biodiversity in the Scheldt Estuary. This is not only due to the altered salt concentrations of the waters caused by dike construction and flood areas, but also because to the input of phosphorus from agriculture. Due to it's indispensable physiological role, phosphorus is one of the most important indicators for water monitoring. The main phosphorus deposits in nature, phosphates, tend to form compounds that are difficult to dissolve and therefore difficult to make available. Agriculture responds by applying phosphorus-containing fertilizers to increase crop yields. This leads to a pan-european conflict between industrialized agriculture and governmental water protection.

The over-fertilization of the groundwater (eutrophication) with phosphorus is one of the biggest problems in the quality assurance of European water bodies, because it triggers excessive growth of algae and aquatic plants. When these die, they are decomposed by microorganisms. In the process, a lot of oxygen is consumed. Oxygen deficits in water bodies have a negative effect on fish and other aquatic organisms, so that, among other things, the population of eels in the Scheldt has already been severely decimated.

The eel, a hybrid, tolerant creature that can live in both salt and fresh water, at depths of 1000 meters or in the salt marches, suffers exemplarily under the consequences of human influence on the Scheldt Estuary. Climate change, eutrophication and pollution are radically altering the largest brackish water salt marshes in Europe."

• Sascha Herrmann