Carl Chun was a German zoologist who led the Valdivia Expedition. The purpose of this scientific expedition was to deepen the discoveries previously made by the Challenger Expedition. The marine biologist was an expert in octopus and squid and took advantage of the expedition to perfect his knowledge of the great depths.
Carl Chun dedicated his entire life to the organisation of the Valdivia Expedition. Towards the end of the 19th century, he was already a teacher recognized by his peers, especially through his study of jellyfish. He also participated in a German expedition to study plankton. He was very inspired by the Challenger Expedition (1872-1876), which had established modern oceanography. That is why in 1897 he presented his project of international research of the ocean floor. In particular, he wished to verify many theories of the mid 19th century which stated that there was no life below 300 fathoms depth (approximately 550m). As a confirmed malacologist (the study of molluscs), he was convinced that these organisms could live below this limit, in abyssal zones. Moreover, lots of great depths zone (including the Mariannes pit) had been discovered during the Challenger Expedition.