The marine macroalgae of Helgoland (North Sea): an annotated list of records between 1845 and 1999

The earliest known records of marine macroalgae from Helgoland (German Eigh t, North Sea) date from the mid-19th century. Since then, 274 marine macroa lgal species have been reported: 77 species of Chlorophycota, 100 species o f Phaeophycota and 97 species of Rhodophycota. Additionally 11 species were only recorded as drift and 51 species as doubtful for Helgoland. The remai ns of the herbarium of Paul Kuckuck, the first curator for botany at the He lgoland Biological Station between 1892 and 1914, are still located there a nd consist of 173 macroalgal species from Helgoland. On comparing this 100- year-old herbarium and other old sources with recent macroalgal records, it became clear that changes in species composition have occurred. After Worl d War II, several species such as Arthrocladia villosa, Corynophlaea crispa , Cutleria multifida, Eudesme virescens, Mesogloia vermiculata, Sporochnus pedunculatus, Antithamnion cruciatum, Apoglossum ruscifolium, Chondria dasy phylla, Helminthora divaricata, Jania rubens and Osmundea ramosissima were not found again. Other species such as Dictyota dichotoma, Leathesia diffor mis, Stictyosiphon soriferus, Helminthocladia calvadosii and Scinaia furcel lata became very rare. Significantly, perhaps, most of these species have a heteromorphic life history with the appearance of the macroscopic phase re stricted to (spring and) summer. Many new species of green algae were recor ded for Helgoland after 1959, due to new substrata and the research activit ies of Peter Kornmann, curator for botany after 1959, and Paul-Heinz Sahlin g his technical assistant. Introductions of species during the considered t ime period were: Bonnemaisonia hamifera, Codium fragile, Mastocarpus stella tus and Sargassum muticum. Type material of the following species is locate d at the Marine Biological Station at Helgoland: Mikrosyphar porphyrae, Por phyra insolita and Ulva tenera.