Variability of particle characteristics in a wave- and current-driven estuarine environment

We deployed in-situ acoustical and optical instrument platforms to measure the flow and physio-biogeochemical characteristics of sediment at multiple depths above the sediment bed in a turbulent, wave- and current-driven shallow estuarine environment. High resolution acoustic Doppler velocimeters provided information with which to understand physical forcing processes. Optical sensors (Laser In-Situ Scattering and Transmissometry (LISST), spectral absorption and attenuation meters, optical backscattering meters, chlorophyll fluorometers, and a Sediment Profile Imaging camera) enabled determination of particle characteristics (concentration, size distribution, and composition) from time scales ranging from minutes to months. Results show that in different flow environments, short-term (minutes to hours) physical forcing acted to resuspend relatively dense, inorganic particles as well as disaggregate less dense, organic flocculates. Particle processes were primarily dependent on wind-driven, wave-induced physical forcing and seasonal biogeochemical variability. The suite of data obtained from the field observations will inform a high-resolution large-eddy simulation model to understand the relationship between particle size distributions and turbulence in wave-driven estuarine environments and how these dynamics affect and are affected by time scales of biogeochemical properties of the suspended particles.