Diatom growth response to physical forcing in a macrotidal estuary: Coupling hydrodynamics, sediment transport, and biogeochemistry

摘要: [1] A two-dimensional, nested grid, hydrodynamic, and reactive-transport model of the macrotidal Scheldt estuary (B/NL) its tributaries has been developed to identify driving forces controlling temporal spatial dynamics primary production during a summer diatom bloom. The hydrodynamic indicates that energy dissipation reaches maximum 90 km upstream from mouth, closely followed by minimum farther upstream. Suspended particulate matter (SPM) is simulated provide transient light conditions in water column. Results show distribution SPM mirrors profile dissipation. highly sensitive fluctuations river discharge, whose influence decreases downstream. Peaks are triggered high discharges can be recorded as far 50 seaward boundary. phytoplankton demonstrate fast response growth changes physical environment, especially those due daily variations discharge which continuously modify concentrations residence times. Episodes persistent low flow lead progressive depletion dissolved silica. Simulated becomes increasingly controlled silica availability, until collapses. spatiotemporal evolution explored over entire domain forcing conditions. net location reveal four different system states identified planes. transition one state other characterizes estuary.