Christian Gottfried Ehrenberg

Biography

Christian Ehrenberg was born in Delitzsch, the son of judge Johann Gottfried Ehrenberg (1757–1826) and his wife Christiane Dorothea Becker (1769–1808). His brother Carl August Ehrenberg (1801–1849) became a botanist and plant collector. He went to Schulpforta and studied theology at Leipzig from 1815 and then shifted to the natural sciences and medicine at Berlin. He received a medical doctorate in 1818 with a dissertation on fungi Sylvae mycologicae Berolinenses. In 1818 he was made member of the Leopoldina Academy. In 1820–1825, on a scientific expedition sponsored by Heinrich von Menu von Minutoli to the Middle East with his classmate and friend Wilhelm Hemprich, he collected thousands of specimens of plants and animals. He investigated parts of Egypt, the Libyan Desert, the Nile valley and the northern coasts of the Red Sea, where he made a special study of the corals. Subsequently, parts of Syria, Arabia and Abyssinia were examined. Minutoli left the expedition when the group was blocked on the Libyan border. Hemprich and Ehrenberg continued to Alexandria and then to Cairo. Hembrich however died of Malaria on 30 June 1825. Ehrenberg managed to return to Berlin. Some results of these travels and of the important collections that had been made were reported on by Alexander von Humboldt in 1826. While in Sudan he designed the mansion of the local governor of Dongola, Abidin Bey. In 1827 he was appointed professor of medicine at Berlin University. He went on another expedition in 1829 into Russia along with others including Alexander von Humboldt and Gustav Rose, (who was the brother of Heinrich Rose). After his return, Ehrenberg published several papers on insects and corals and two volumes Symbolae physicae (1828–1834), in which many particulars of the mammals, birds, insects, etc., were made public. Other observations were communicated to scientific societies.

Family

Ehrenberg married Gustav Rose's cousin Julie Rose (1804–1848) in 1831. After their first son died in infancy they had four daughters: Helene (born 1834), Mathilde (1835–1890), Laura (born 1836) and Clara Ehrenberg (1838–1916). His youngest daughter Clara Ehrenberg was his assistant for over twelve years. She aided his scientific research, organised and indexed his collections and correspondence, and prepared a taxonomic reference book. Clara was also a published scientific illustrator. Helene married the botanist Johannes von Hanstein and Mathilde married the mineralogist Karl Friedrich August Rammelsberg. In 1852 Ehrenberg married his second wife, Karoline Friederike Friccius (1812–95), who was related to the chemist Eilhard Mitscherlich. The couple had one son, Hermann Alexander Ehrenberg.

Microscopic organisms

For nearly 30 years Ehrenberg examined samples of water, soil, sediment, blowing dust and rock and described thousands of new taxa, among them well-known flagellates such as Euglena, ciliates such as Paramecium aurelia and Paramecium caudatum, and many fossils, in nearly 400 scientific publications. He was particularly interested in a unicellular group of protists called diatoms, but he also studied, and named, many species of radiolaria, foraminifera and dinoflagellates.

This research had an important bearing on some of the infusorial earths used for polishing and other economic purposes; they added, moreover, largely to our knowledge of the microorganisms of certain geological formations, especially of the chalk, and of the marine and freshwater accumulations. Until Ehrenberg took up the study it was not known that considerable masses of rock were composed of minute forms of animals or plants. He thus became a pioneer of micropaleontology. He also demonstrated that the phosphorescence of the sea was due to organisms.

He continued until late in life to investigate the microscopic organisms of the deep sea and of various geological formations.

He died in Berlin on 27 June 1876.