A sublittoral transect (P3) in the North of Helgoland that had been investigated ~40 years earlier by Lüning (1970) was traversed again. Scuba dives were carried out between 24.06.2005 and 19.08.2005. For each sampling point, time, date and coordinates were given as well as the corrected depth in m mean low water spring tide. Along the transect, substrate and topography were recorded. Relative frequency and cover of 32 species grown attached to the seafloor and cover of 12 epiphytic species were obtained.
A sublittoral transect (P3) in the North of Helgoland that had been investigated ~40 years earlier by Lüning (1970) was traversed again. Scuba dives were carried out between 21.04.2005 and 23.06.2005. At different sampling points (Location ID: P1-P44; start with P1 every new day) along the transect, substrate and topography was recorded and every 5m occurrence and the cover was obtained of the dominant brown algae Fucus serratus, Sargassum muticum, Laminaria digitata, L. hyperborea and Saccharina latissima. The occurrence was measured qualitatively as present/absence (1/0) and the cover was estimated semi-quantitative according to the Kautsky scale as 0 for not present to 100 as 100% cover (Kautsky, 1995). Furthermore, the transect was split into different zones (1-7) depending on the algal vegetation according to the master thesis of C. Gehling (2006). For each sampling point, time, date and coordinates were given as well as the corrected depth in m mean low water spring tide.
In 2005, the species composition and spatial distribution of the seaweed community were investigated in the frame of diving surveys along a sublittoral transect in the North of Helgoland that had been investigated ~40 years earlier by Lüning (1970). The cover of dominant brown seaweeds, Fucus serratus, Sargassum muticum, Laminaria digitata, L. hyperborea and Saccharina latissima, was semi-quantitatively assessed to define vegetation zones. Within each zone, all macroalgal species were estimated quantitatively in 3 to 6 random 1 m² quadrats. Additionally, a replicated biomass survey was performed at 6 depths (0.5, 2, 4, 6, 8 and 10 m below mean low water spring tide). The survey investigated the occurrence, cover and relative frequency of the algae community and information about fresh mass and dry mass were obtained. For kelps also stipe length, blade area, blade fresh mass, age and fresh mass of epiphytes was recorded.
A sublittoral transect (P3) in the North of Helgoland that had been investigated ~40 years earlier by Lüning (1970) was traversed again. Scuba dives were carried out between 13.07.2005 and 25.08.2005. For each sampling point, time, date and coordinates were given as well as the depth in m mean low water spring tide. 0.25 m² frames were used to obtain the species composition, total fresh mass and total dry mass. In addition, 1 m² frames were used to record the kelp community by counting the individuals and measuring kelp stipe length, kelp blade area, kelp blade fresh mass, kelp age and fresh mass of epiphytes on the kelp stipes. Equal Location IDs represent the same frame.