Material transport from the nearshore to the basinal environment in the southern Baltic Sea: 1. Processes and mass estimates

• Published in: Journal of marine systems 2002-03, Vol.35 (3-4), p.133-150
• Main Authors: Christiansen, C, Edelvang, K, Emeis, K, Graf, G, Jahmlich, S, Kozuche, J, Laima, M, Leipe, T, Loffler, A, Lund-Hansen, L C, Miltner, A, Pazdro, K, Pempkowiak, J, Shimmield, G, Shimmield, T, Smith, J, Voss, M, Witt, G
• Format: Article
• Language: English
• Subjects: Brackish; Marine
• ISSN: 0924-7963
• DOI: 10.1016/S0924-7963(02)00126-4

Processes involved in erosion, transport and deposition of cohesive materials are studied in a transect from shallow (16 m) to deep (47 m) water of the SW Baltic Sea. The wave- and current-induced energy input to the seabed in shallow water is high with strong variability and suspended matter concentrations may double within a few hours. Primary settling fluxes (from sedimentation traps) are less than 10 g m super(-2) day super(-1), whereas resuspension fluxes (evaluated from sedimentation flux gradients) are 15-20 times higher and the residence time for suspended matter in the water column is 1-2 days. Settling velocities of aggregates are on average six times higher than for individual particles resulting in an enhanced downward transport of organic matter. Wave-induced resuspension (four to six times per month) takes place with higher shear stresses on the bottom than current-induced resuspension (three to five times per month). The short residence time in the water column and the frequent resuspension events provide a fast operating benthicupelagic coupling. Due to the high-energy input, the shallow water areas are nondepositional on time scales longer than 1-2 weeks. The sediment is sand partly covered by a thin fluff layer during low-energy periods. The presence of the fluff layer keeps the resuspension threshold very low (