He spent much of his life studying the collections made during the expedition, and was responsible for discovering many marine organisms, including the vampire squid.

Chun went to the Lessing Gymnasium and became interested in zoology from an early age thanks to the Senckenberg Museum in Frankfurt where he listened to lectures by Fritz Noll, Hermann Theodor Geyler, and Karl von Fritsch.

Chun became deeply interested in oceanic organisms and worked at the Naples Zoological Station where he studied and published a monograph on comb jellyfish under Anton Dohrn.

[2][3] Deep sea exploration had been popularized by the British Challenger Expedition (1872–1876) and the Germans, not to be left behind, funded Chun's proposal made in 1897 at the meeting of the Deutsche Naturforscher und Aertze in Leipzig.

[4] The material collected was described in 24 volumes that were published until 1940 with more than 70 specialists involved including Sir John Murray of the Challenger expedition.

He published in a popular narrative of the "Valdivia" expedition, Aus den Tiefen des Weltmeeres (1900) which captured the public imagination of the period.