title: Short-term impact of deep sand extraction and ecosystem-based landscaping on macrozoobenthos and sediment characteristics.
abstract: We studied short-term changes in macrozoobenthos in a 20m deep borrow pit. A boxcorer was used to sample macrobenthic infauna and a bottom sledge was used to sample macrobenthic epifauna. Sediment characteristics were determined from the boxcore samples, bed shear stress and near-bed salinity were estimated with a hydrodynamic model. Two years after the cessation of sand extraction, macrozoobenthic biomass increased fivefold in the deepest areas. Species composition changed significantly and white furrow shell (Abra alba) became abundant. Several sediment characteristics also changed significantly in the deepest parts. Macrozoobenthic species composition and biomass significantly correlated with time after cessation of sand extraction, sediment and hydrographical characteristics. Ecosystem-based landscaped sand bars were found to be effective in influencing sediment characteristics and macrozoobenthic assemblage. Significant changes in epifauna occurred in deepest parts in 2012 which coincided with the highest sedimentation rate. We recommend continuing monitoring to investigate medium and long-term impacts.
authors.affiliation: IMARES Wageningen UR - Institute for Marine Resources & Ecosystem Studies, Department of Ecosystems, PO Box 167, 1790 AD Den Burg, The Netherlands; Wageningen UR - Department of Aquatic Ecology and Water Quality Management, P.O. Box 47, 6700 AA Wageningen, The Netherlands. Electronic address: maarten.dejong@wur.nl.
authors.forename: Maarten F
authors.initials: MF
authors.lastname: de Jong
authors.affiliation: IMARES Wageningen UR - Institute for Marine Resources & Ecosystem Studies, Department of Ecosystems, PO Box 167, 1790 AD Den Burg, The Netherlands.
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Baptist
authors.affiliation: IMARES Wageningen UR - Institute for Marine Resources & Ecosystem Studies, Department of Ecosystems, PO Box 167, 1790 AD Den Burg, The Netherlands; Wageningen UR - Department of Aquatic Ecology and Water Quality Management, P.O. Box 47, 6700 AA Wageningen, The Netherlands.
authors.forename: Han J
authors.initials: HJ
authors.lastname: Lindeboom
authors.affiliation: Institute for Marine and Atmospheric Research Utrecht, Faculty of Geosciences, Utrecht University, PO Box 80.115, 3508 TC, Utrecht, The Netherlands.
authors.forename: Piet
authors.initials: P
authors.lastname: Hoekstra
mesh_terms: D000818:Animals; D044822:Biodiversity; D018533:Biomass; D049872:Bivalvia; D017753:Ecosystem; D004777:Environment; D004784:Environmental Monitoring / Q000379:methods*; D019015:Geologic Sediments; D012822:Silicon Dioxide
chemical_list: D012822:Silicon Dioxide
keywords: Dredging; Hydrodynamics; Mining; North Sea; Sedimentation rate