Major projects

Integrated Network for Production and Loss Assessment in the Coastal Environment


Project location Netherlands
Starting date 01 March 2011
Completion date 01 March 2013
Client Netherlands Institute of Ecology, Centre for Estuarine and Marine Ecology (NIOO-KNAW)
Partners Royal Netherlands Institute for Sea Research (NIOZ),
Institute for Environmental Studies (IVM) at Free University of Amsterdam
Project leader M.S. Salama (for ITC part)
Project officer Bert Boer
Project type Contract research
Budget EUR 164,329 (ITC part)

Research output

Philippart, C.J, Salama, M.S., Kromkamp, J.C., Van der Woerd, H., Zuure, A. F. and Cadée, G.C. (2012). Long-term variation in turbidity in the western Wadden Sea as derived from corrected Secchi disk readings. Journal of Sea Research, Accepted.

Salama, M. S.,Van der Velde, R.; Van der Woerd, H.J.; et al. (2012) Technical notes: Calibration and validation of geophysical observation models. Biogeosciences 9,6: 2195-2201 (IF,4.2)

Summary of results

Understanding the spatial and temporal variations of primary production (PP) in the Wadden Sea environments is essential for preserving their ecological and socio-economical services. Technological and scientific advances have promoted remote sensing to become a powerful tool for identifying spatial and temporal variability of surface phytoplankton biomass, phytoplankton functional types, and primary production. Despite these developments, there are no frequent information on the spatiotemporal distribution of primary productivity in the Wadden Sea environments (i.e. water and mudflats) at a fine scale (e.g. less than 1 km) and repeated temporal coverage (e.g. less than 1 month).

As part of the IN-PLACE project, we developed remote sensing methods to quantify the primary productivity in the Wadden Sea environments at a spatial resolution of 300m for water and 30m for mudflats. We used the Vertically Generalized Production Model (VGPM) to assess the rate of daily primary production in the euphotic layer of the water (see Fig. 1). Microphytobenthos primary productivity is estimated for the top sediment layer (2mm depth) using Normalized-Differences-Vegetation-Index (NDVI) as a proxy for microphytobenthic biomass (see Fig. 2). Verification of the derived results is preliminary and based on comparing remote sensing products of chlorophyll-a to measured values in the water column (see Fig. 3).

Remote sensing products rendered the spatial distribution and the yearly pattern of PP variations (see Fig. 4). Although the seasonal variation of PP is well understood and driven by temporal changes in light, temperature and nutrient availability, the reason for the interannual variability in primary production is often unclear, and quantitative measures of this cycle in time and space might help resolve the reasons behind the interannual variability in productivity.

More information:

Fig. 1: Primary production maps produced from MERIS and MODIS using the Vertically Generalized
Production Model (VGPM) model for the year 2011. Spatial resolution 300 meter, projection Lat Long,


Fig. 2: Microphytobenthos
primary production of mudflats.


Fig. 3: Validation of the remote sensing-based method to
derived Chl-a from observed radiance. RMSE: root mean
square error, MARE: mean absolute relative error.


Fig. 4: Averaged area time series of the Dutch Wadden Sea for the period 2003-2011; (a) yearly mean, (b) climatology, here the zero PP in January and December indicate no data available for these two months, and (c) the monthly mean.


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