|Time variations in interstitial nutrient concentrations at an exposed subtidal station in the Dutch Wadden Sea|
Rutgers van der Loeff, M.M. (1980). Time variations in interstitial nutrient concentrations at an exposed subtidal station in the Dutch Wadden Sea. Neth. J. Sea Res. 14(2): 123-143
In: Netherlands Journal of Sea Research. Netherlands Institute for Sea Research (NIOZ): Groningen; Den Burg. ISSN 0077-7579, more
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- Rutgers van der Loeff, M.M.
A permanent in situ pore water sampler was developed and used for the study of short term variations in pore water constituents of sandy sediments. Interstitial nutrient concentrations were measured from March to December 1978 in a subtidal sediment of the Wadden Sea, exposed to current and wave action. Three depth intervals could be distinguished:In the first layer, from 0 to 10 cm, the concentrations of ammonia, phosphate and silica differed little from those in the overlying water, an indication for a high apparent diffusion coefficient (D≥5.10-5cm².s-1). In April nitrification could be demonstrated. The intermediate layer, from 10 to 25 cm, showed rapid changes in nutrient concentrations as a result of short mineralization periods and changing redox conditions.The layer below 25 cm was relatively stable. A variation in silica concentrations is probably seasonal. The rapid changes observed, show that is generally not justified to make a steady state approximation in kinetic models describing depth profiles of nutrient concentrations.The mineralization in April and May in the intermediate layer only liberated ammonia and phosphate, whereas during the decomposition of apparently freshly sedimented material in October, silicate was also provided.