Towards continuous long-term measurements of suspended particulate matter (SPM) in turbid coastal waters

The dynamics of sediment transport in the East Frisian Wadden Sea are important for the coastal zone and for ecosystem functioning. The tidal inlets between the East Frisian islands connect the back-barrier intertidal flats to the North Sea. Here, concentrations of suspended particulate matter (SPM) in the water column are highly variable, depending on weather conditions and tides. In order to estimate the nature and quantity of sediment transport, in situ measurements were carried out at a Time Series Station in the tidal inlet between the islands of Spiekeroog and Langeoog. This study shows the suitability of multispectral transmissometry (MST) for obtaining long-term SPM measurements with high resolution. The comparability of this technique to the standard filter method and the laser diffraction method [laser in situ scattering and transmissometry (LISST)] is demonstrated. In addition, the Junge coefficients derived from both MST and LISST measurements are compared. A time series of SPM data covering nearly 4 months is presented. As a major result, the data reveal that a single storm surge can have less impact on SPM dynamics than longer-lasting gales. This high-resolution long-term data set is very valuable for modelling suspended matter flux. It also provides background information for studying the influence of SPM dynamics on coastal sediments.

[1]  Amanda L. Whitmire,et al.  Light scattering by random shaped particles and consequences on measuring suspended sediments by laser diffraction , 2008 .

[2]  V. Ernstsen,et al.  In-situ observation of aggregate dynamics in a tidal channel using acoustics, laser diffraction and optics , 2007 .

[3]  B. Flemming,et al.  Quantifying concentration and flux of suspended particulate matter through a tidal inlet of the East Frisian Wadden sea by acoustic doppler current profiling , 2000 .

[4]  R. Reuter.  Characterization of marine particle suspensions by light-scattering .2. experimental results , 1980 .

[5]  G. Krause,et al.  On different time scales of suspended matter dynamics in the Weser estuary , 2001 .

[6]  K. Bolding,et al.  Hydrodynamics and sediment dynamics in the German Bight. A focus on observations and numerical modelling in the East Frisian Wadden Sea , 2009 .

[7]  K. Bolding,et al.  On the circulation in the East Frisian Wadden Sea: numerical modeling and data analysis , 2003 .

[8]  M. Pejrup,et al.  Modelling of cohesive sediment transport in a tidal lagoon—an annual budget , 2005 .

[9]  M. Beck,et al.  Non-conservative behaviour of molybdenum in coastal waters: Coupling geochemical, biological, and sedimentological processes , 2007 .

[10]  L. Prieur,et al.  Absorption by dissolved organic matter of the sea (yellow substance) in the UV and visible domains1 , 1981 .

[11]  Y. C. Agrawal,et al.  Instruments for particle size and settling velocity observations in sediment transport , 2000 .

[12]  A. Lane,et al.  Observational data sets for model development , 2000 .

[13]  M. Simon,et al.  Physical and biogeochemical controls of microaggregate dynamics in a tidally affected coastal ecosystem , 2006 .

[14]  E. Stanev,et al.  On the sensitivity of the sedimentary system in the East Frisian Wadden Sea to sea-level rise and wave-induced bed shear stress , 2006 .

[15]  Kevin Ruddick,et al.  Variability of the inherent and apparent optical properties in a highly turbid coastal area: impact on the calibration of remote sensing algorithms , 2006 .

[16]  Rainer Reuter,et al.  A hydrographic time series station in the Wadden Sea (southern North Sea) , 2009 .

[17]  U. Stute,et al.  Polychromatic transmissometer for in situ measurements of suspended particles and gelbstoff in water. , 1997, Applied optics.

[18]  H Haardt,et al.  Measurement of the spectral attenuation to support biological-research in a plankton tube experiment , 1980 .

[19]  R. Riethmüller,et al.  Impact of Density Gradients on Net Sediment Transport into the Wadden Sea , 2008 .

[20]  B. Flemming,et al.  Muddy coast dynamics and resource management , 2000 .

[21]  Yogesh C. Agrawal,et al.  The optical volume scattering function: Temporal and vertical variability in the water column off the New Jersey coast , 2005 .

[22]  Rainer Reuter,et al.  PATTERNS OF SUSPENDED MATTER IN THE EAST FRISIAN WADDEN SEA: COMPARISON OF NUMERICAL SIMULATIONS WITH MERIS OBSERVATIONS , 2006 .

[23]  J. Bartholdy,et al.  Storm surge effects on a back-barrier tidal flat of the Danish Wadden Sea , 2001 .

[24]  B. Flemming,et al.  Suspended sediment transport in the German Wadden Sea—seasonal variations and extreme events , 2009 .

[25]  K. Lettmann,et al.  Modeling the impact of wind and waves on suspended particulate matter fluxes in the East Frisian Wadden Sea (southern North Sea) , 2009 .

[26]  Stephen G. Monismith,et al.  Modeling the influence of wave-enhanced turbulence in a shallow tide- and wind-driven water column , 2008 .

[27]  E. Stanev,et al.  First- and higher-order dynamical controls on water exchanges between tidal basins and the open ocean. A case study for the East Frisian Wadden Sea , 2003 .