Multiparametric investigation of North Sea particulate matter. Preliminary results in the Skagerrak

Abstract

During the Tramanor cruise, in July 1988, seawater and particle samples were collected along a vertical profile (530 m depth) located in the Skagerrak, a crossing-area for different water-masses and particle pools. A sampling strategy was developed to ensure the homogeneity of the different sets of subsamples subjected to analysis by closely-coupled complementary techniques: turbidimetry, granulometry, scanning electron microscope (SEM) observations, Tracor analyses, particulate organic carbon and nitrogen measurements, and neutron activation analysis (NAA). The Baltic outflow is found in the topmost 20 m water-column (salinity approximately equals 23.5; temperature approximately equals 18 degree C) overlying North Sea waters (salinity approximately equals 35; temperature approximately equals 6 degree C). Surface waters undergo a plankton bloom, dominated by Dinoflagellates and Coccolithophoridae. The former, characterized by high C/N ratios ( approximately equals 15; cellulosic thecae), play a significant role in the biological recycling of Zn. The latter accumulate over the halocline as typically observed in frontal structures. The detrital phase mainly consists of clay minerals. Manganese is highly enriched relative to shale-type material together with Fe, Co and Zn