Beach morphology and food web structure: comparison of an eroding and an accreting sandy shore in the North Sea

摘要: Food web components and inorganic nutrients were studied on two sandy shores of the adjacent barrier islands Sylt Romo in North Sea, differing morphodynamics. Implications high low wave energy food structure assessed. The shore represents a dynamic intermediate beach type, while is morphologically stable dissipative. On steep-profiled, coarse-grained shore, strong hydrodynamics resulted erosion fluxes organic material through beach, but prevented any storage sources. In contrast, flat-profiled, fine-grained with accretion, accumulated carbon from surf waters. At Sylt, oxic nutrient regeneration prevailed, anoxic mineralization was more important at Romo. Macrofauna impoverished compared community Correspondingly, abundances epibenthic predators such as shrimps, crabs, fish, shorebirds also lower Sylt. Meiofauna abundant both shores, differed taxonomic composition. Several major taxa represented fairly equal proportions individual numbers well-oxygenated nematodes strongly dominated assemblage Thus, cold-temperate, highly subject to erosion, "small web" dominates. Organisms are agile quickly exploit fresh material. Larger organisms abound under stable, dissipative accreting conditions, where some materials may accumulate zoomass builds up support numerous visitors higher trophic levels.