Largest polar expedition to date leads to discovery of large sponge gardens
During the MOSAiC expedition, which took place from September 2019 until October 2020 and was coordinated by the Alfred Wegener Institute — which is lead by Hector Fellow Antje Boetius- researchers from Bremen, Bremerhaven and Kiel and their international partners discovered lush sponge gardens in the Arctic deep sea.
The sponges live on the tops of extinct underwater volcanoes in the central Arctic Ocean, the most nutrient-poor sea on Earth. Apparently, the sponges feed on the remains of extinct animals. The sea is permanently covered by ice and thus hardly reached by light, which is why almost no life is possible there. The densely populated ecosystem dominated by sponges probably originated from a substance that seeped through the ocean floor thousands of years ago, supporting life with numerous animals. After these animals became extinct, the sponges were able to feed on the remains with the help of symbionts.
The research team also found that the sponges now help shape the ecosystem by producing needles (spiculae) that form a mat on which the sponges crawl. The unique ecosystem was discovered at depths of 600 to 700 meters in Arctic and occupies an area of more than 15 square kilometers. This discovery, and the research that accompanies it, helps to better understand and protect the diversity of the Arctic seas.