Karl August Möbius (7 February 1825 in Eilenburg – 26 April 1908 in Berlin) was a German zoologist who was a pioneer in the field of ecology and a former director of the Museum für Naturkunde in Berlin.
Möbius was born in the town of Eilenburg in Saxony. At the age of four he attended primary school at the Bergschule Eilenburg, and at the age of 12 he was sent by his father to train as a teacher. In 1844 he passed the exams with distinction and began working as teacher in Seesen, on the northwest edge of the Harz mountain range. In 1849 he began studying natural science and philosophy at Humboldt University in Berlin. After he graduated, he taught zoology, botany, Mineralogy, geography, physics, and chemistry at the Johanneum High School in Hamburg.
Between 1868 and 1870 he studied the ecology of oyster banks, primarily to determine the potential for oyster farming in coastal areas of Germany. This work resulted in two landmark publications: Über Austern- und Miesmuschelzucht und Hebung derselben an der norddeutschen Küste (1870, in English: On oyster and blue mussel farming in coastal areas of Northern Germany), and Die Auster und die Austernwirtschaft (In English: Oyster and oyster farming), in which he concluded that oyster farming was not a realistic option for Northern Germany. More importantly, he was first to describe in detail the interactions between the different organisms in the ecosystem of the oyster bank, coining the term "biocenose". This remains a key term in synecology (community ecology).
In 1888 Möbius became the director of the Zoological Collections of the Museum für Naturkunde in Berlin, and Professor of Systematic and Geographical Zoology at the Kaiser Wilhelm University, Berlin, where he taught until he retired in 1905, at the age of 80.