The impact of nutrient spiraling in the tidal freshwater zone of estuaries: the Scheldt, a case study.

Estuaries are one-dimensional flow systems, transforming particulate and dissolved substances before reaching the coastal zone. However, estuarine substances may be temporarily trapped in intertidal marshes and mudflats, the primary low-flow zones. These processes, referred to as spiraling, allow intense biogeochemical processing with major consequence for the functioning of estuaries as nutrient filters. The tidal freshwater area has received scarce attention compared to the saline counterpart. It is my objective to study the biogeochemical consequences of nutrient spiraling in the freshwater zone of the Scheldt estuary. I hypothesize that in this estuary spiraling by lateral temporary storage in tidal marshes and vertical exchange between flooding water and the intertidal sediment is equally important as the processes in the pelagic. Lateral storage from marshes (1) and vertical sediment-water exchange from mudflats (2) will be examined to scale up an existing Scheldt model (3), allowing to incorporate the effects of nutrient spiraling for the first time from intertidal marshes and mudflats on the pelagic processes in the tidal freshwater zone.

Keywords:ECOLOGY, ECOSYSTEMS

Disciplines:Ecology, Environmental science and management, Other environmental sciences