Subject of PhD thesis
Modelling submarine groundwater discharge and associated solute transport from Java, Indonesia.
Riverine nutrient fluxes are well researched and recognized as important fresh water and nutrient source for coastal marine waters. However, nutrient input by submarine groundwater discharge (SGD) receives increasing attention. Many local studies analyzed local SGD over the last years, but only a few assessed its relevance for regional and global matter fluxes. Groundwater discharge into coastal waters is generally below river water discharge. On the other hand, highly anthropogenic influenced groundwater systems can release much higher nutrient loads into the ocean than rivers. The large retention potential of phosphorus in aquifers compared to the high nitrogen mobility increases the ratio of these nutrients (the N:P ratio) in aquifers. Hence, substantial input of highly anthropogenic influenced groundwater can increase N:P ratios in coastal waters.
In my PhD Thesis I will identify and analyze mechanisms of fresh and saline groundwater transport and mixing in coastal aquifers and its associated nutrient fluxes, by applying the finite element software FEFLOW, supplemented by GIS. The study island Java in Indonesia has high seasonal precipitation and anthropogenic nutrient loads, which will facilitate to study SGD-mechanisms. In different coastal groundwater catchments I will study the local hydrogeology and model the associated nutrient transport processes. The results will be used to (1) quantify total nutrient inputs driven by SGD into coastal waters of the highly anthropogenic influenced tropical island Java, by (2) identifying general mechanisms of flow and nutrient transport of SGD. Finally, (3) the identified mechanisms will help to improve global nutrient budgets for the ocean and emphasize its global ecological importance.