Schygulla, C. and Peine, F., 2013. Nienhagen Reef: abiotic boundary conditions at a large brackish water artificial reef in the Baltic Sea.
This paper briefly describes the abiotic boundary conditions at the artificial reef area in Nienhagen on the coast of the German Baltic Sea. This reef, the largest man-made reef in the Baltic Sea (about 4 ha), was built in autumn 2003 by the state research institute for agriculture and fisheries (LFA) in 12 m water depth. The artificial reef area in the Mecklenburg Bight was mainly constructed to enhance fish populations, especially for the commercially important Baltic cod population. Reef monitoring of abiotic factors (temperature, salinity, O2, pH) started in 2003 and is still in progress, complemented by sediment sampling. The reef rises from the seafloor, up to 3 m at the central structures and between 1 and 2 m in the outer regions. The reef units were chosen for their long life and high stability and for the creation of cavity systems and hideaways for juvenile organisms. The used concrete material was composed in a special way to reach neutral pH values, with regard to the surrounding waterbody, on the surfaces of the structures. The reef units were placed on a strong marl layer with a thin sediment layer of sand and gravel. The grain size distribution and sediment composition within the reef area has changed compared with the surrounding areas since the installation of the reef units.
