| Abstract | *The SIBES sampling design encompasses the entire Dutch Wadden Sea, with sampling at 500 m intervals and 10 % random sample points.*Sibes sampling is completed on an annual basis in summer from June to ~September, depending on weather. The NIOZ research vessel, Navicula, is used to access the sample areas across the Wadden Sea, as Navicula has been designed specifically for this type of work. During low tide this vessel lies on the dry tidal flat, and can thus be used as a basis for the sampling by foot. In areas where it is too deep or muddy to access by foot, small inflatable boats are sent from the Navicula to sample the SIBES sites. Sampling locations, ~4800 in total, were found with a handheld GPS (WGS84 as map datum). At each site sampled by foot, a single core of 0.0175 m2 is taken up to a depth of ~25 cm. By boat, two cores of 0.018 m2 are taken to a depth of ~25 cm. While in the field, sediment samples were taken using a centrifuge tube to a depth of 4 cm and frozen on-board. The sediment samples were taken at all sample points in 2009-2014 and at 1 km intervals in 2008All shellfish were identified to species level and measured for their maximum length using digital callipers (precision of 0.01 mm). An ash free dry mass was then determined for each individual greater than 8 mm in size or for multiple individuals together when their size was smaller than 8 mm in length. Ash free dry mass or the biomass of an organism can provide important information about the production of a given estuary, i.e. its “carrying capacity” (Dame & Prins 1997), the feeding conditions for the birds (Beukema et al. 1993, Zwarts 1996), and changes in macrofaunal quality in space and time, e.g. in terms of growth (Cardoso et al., 2007) To determine the ash free dry mass, the wet meat of an organism is placed into a crucible and then dried at 60°C for 48 hours. Once dried, the dry sample goes into a desiccator to cool prior to weighing to an accuracy of four decimal places (Mettler Toledo XS204). The dried organism is then put into an incinerator where the organic matter is burnt, so that only the ashed matter remains (560°C for 5 hours). Once incinerated, the ashed sample goes into a desiccator to cool prior to weighing the ashed mass to an accuracy of four decimal places. *For the methods of SIBES desingn and analysis:*Bijleveld, A. I., J. A. van Gils, J. van der Meer, A. Dekinga, C. Kraan, H. W. van der Veer, and T. Piersma. 2012. Designing a benthic monitoring programme with multiple conflicting objectives. Methods in Ecology and Evolution 3:526-536.Compton, T. J., S. Holthuijsen, A. Koolhaas, A. Dekinga, J. ten Horn, J. Smith, Y. Galama, M. Brugge, D. van der Wal, J. van der Meer, H.W. van der Veer, and T. Piersma. 2013. Distinctly variable mudscapes: Distribution gradients of intertidal macrofauna across the Dutch Wadden Sea. Journal of Sea Research 82: 103-116.*Acknowledgements please insert in papers and reports when using this data*We thank the SIBES core-team: Tanya J. Compton, Anita Koolhaas, Anne Dekinga, Sander Holthuijsen, Job ten Horn, Niamh McSweeney, Lise Klunder, Maarten Brugge, Jaap van der Meer, Henk W. van der Veer and Theunis Piersma. SIBES relies on the help of numerous volunteers, as well as staff and Phd-, MSc-, and BSc-students. We thank the crew of the RV Navicula for their work during the sampling season: Bram Fey, Hein de Vries, Wim Jan Boon, Tony van der Vis and Kees van der Star. In 2008-2012 the SIBES-monitoring was carried out with financial support from NAM, NWO-ALW (ZKO programme) and Royal NIOZ.*Contact*More information can be found on http://www.nioz.nl/sibes. If you require more detailed information please contact us for possibilities.This research was initiated by Royal NIOZ, ZKO and NAM. At present it is supervised and funded by royal NIOZ and also by NAM. |