Natural seagrass produces biomass, which, after dying off, is washed to shore. This is a natural process, which on German coasts causes the accumulation of large quantities of seagrass detritus. Detritus along beaches has a high ecological value: it provides food and habitat for birds and insects living on the coast, as well as it protects the dunes behind it. Furthermore, during decomposition nutrients are released, a process that provides important fertiliser to adjacent ecosystems. Since both, temperature and humidity have an impact on the decomposition of organic materials, climate change could affect detritus deposition: on the one hand by changes in air and water temperature and on the other hand by sea level rise and associated increase in inundation times and frequencies.

Seagrass detritus has always been used commercially. Nowadays the production of fertilizers and insulation materials are the most common forms of use. Furthermore, our industrial partner Soiltec has developed a fire-proof mat for revegetation and erosion control in sensitive areas. Due to the installation of groins, however, the quantity of detritus has greatly increased. Since the negative effects, for example on tourism, have also increased, a large proportion of the detritus is disposed of costly in many places.

In this Workpackage, we will investigate the extent to which the degradability of Zostera marina detritus is altered by increased temperature and prolonged flooding time, as well as the effect this has on the detritus habitats. For this purpose, experiments will be conducted, in which the decomposition rates are examined under modified conditions. The information on the decomposition times of seagrass detritus will also be used to explore whether seagrass fibres can be used as filler in biodegradable compound materials with the vision to re-integrate detritus in the material used to produce ASG and/or their base layers.