Happy birthday Hydrobiologia! 70 years young and still growing

Hydrobiologia started its existence in March 1948 by publishing a first volume of 476 pages, and already then focused on the biology and ecology of aquatic organisms. After 70 years, the focus of the journal is still similar, but the diversity of approaches increased during the seven decades of its existence. To celebrate the 70 years of Hydrobiologia, we here address some emerging trends in the history of publications in Hydrobiologia.