The surficial sediments of Königshafen-variations over the past 50 years

Abstract

The investigation highlights the untypical nature of the intertidal sediments of the sheltered K6nigshafen embayment in the north of the island of Sylt The area is characterized by medium sand, which might be explained by aeolian input from the adjacent dunes. Mudflats and sandy mudflats build up the western part of the bay. Other sandy mudflats, all with a small spatial distribution, are associated with mussel beds. A peculiarity of the sediments in the K6nigshafen embayrnent are the gravel and cobbles along the northern shore and parts of the southern shore. These can be interpreted as residual sediments from former stages of the "Ellenbogen" spit. A comparison of the present results with earher studies by Wohlenberg (1937) and Felix (1981) shows a dechne in rnudflats and an increasing consolidation of the mud in the period up to 1981. Since 1981 the sediment distribution has not changed, hence this tidal embayment can today be qualified as representing a relatively stable depositional area.

Temporal variations in microbenthic metabolism and inorganic nitrogen fluxes in sandy and muddy sediments of a tidally dominated bay in the northern Wadden Sea

“…The sediments of the bay vary in grain-size spectrum from mud to cobbles (Austen, 1994). At the head of the bay, where protection from prevailing winds and waves creates a deposition area, the sediment is fine grained with a modal particle size of < 0.1 (Fig.…”

“…Large parts of the south and north shores are dominated by coarse sand with a modal particle size > 0.35 mm. It has been suggested that the presence of coarse and medium sand in high intertidal K6nigshafen sediments is due to aeolian input from adjacent dunes (Austen, 1994).…”

“…The benthic fauna consists of relatively few species with a specific dominant compo- Austen, 1994) nent in each of the dominant sediment types (Jensen et al, 1996). The epifaunal mudsnail, Hydrobia ulvae, dominates in the high intertidal coarse sands with densities ranging from 5000 m -2 in winter to 10 000-25 000 m -2 in summer.…”

Temporal and spatial variations of biodeposits—A preliminary investigation of the role of fecal pellets in the Sylt-Rømø tidal area

“…In K6nigshafen the sediment is characterized by m e d i u m sand (Austen, 1992(Austen, , 1994. The present study concerning the distribution of fecal pellets at the sediment surface was undertaken on an E-W profile in K6nigshafen, and a NNE-SSW profile in the inner part of Keitum Bay (Fig 1).…”

Long-term changes of intertidal and subtidal sediment compositions in a tidal basin in the northern Wadden Sea (SE North Sea)

“…According to the correlation between the grain settling velocities and the maximum Xow velocities (Flemming and Nyandwi 1994), the current velocities are not high enough to transport a signiWcant amount of sand into the bay. Austen (1994) found evidence for an aeolian input of sand into the Königshafen from surrounding dunes. Wohlenberg (1937) assumed that the high amount of sand can only be explained by migrating dunes.…”