“The vast seafloor of the CCZ, with animals living on and in the nodules and sediment, comprises a unique deep-sea habitat that is little-known. More work needs to be done to understand the impact of nodule collection on the biological community and how we can conserve and protect it for future generations,” said NUS Tropical Marine Science Institute (TMSI) Senior Research Fellow Dr Tan Koh Siang, one of the members of the expedition team.
The abyssal floor of the CCZ may appear barren, but the team found hundreds of deep-sea species, with many possibly new to science. Living in the cold seafloor of the CCZ, many of these creatures subsist almost exclusively on food that falls from above, and are often very small, measuring less than two centimetres.
“My main interest is in a group of crustaceans known as tanaids, which are somehow very common in the CCZ. These tiny animals have a slender body and most species live in tubes that they construct using silk secreted from their legs. Because of their numbers and widespread distribution, it is an ideal candidate to be considered as an environmental indicator,” shared Mr Chim Chee Kong, TMSI Research Associate.
Box corers were used in the sampling of the seabed. After a piece of the seabed has been brought up from the sea floor, the team would take samples of the sediment to study the microbes, foraminiferans, meiofauna, macrofauna and megafauna.
“I was very excited to find tubes made by one of the attached stages - called polyps - of a jellyfish on polymetallic nodules. As these tubes were quite common, it would be interesting to observe viable polyps’ occurrence and abundance as deep-sea landscapes change over time with increased human activity. Empty tubes also provide attachment surfaces for other organisms such as foraminifera,” enthused Ms Iffah bte Iesa, Curator at the NUS Lee Kong Chian Natural History Museum.
The team discovered three species which are potentially new to science, and they include a deep-sea sponge belonging to the family Polymastiidae, some isopod crustaceans, as well as a unique type of Foraminifera — single-celled organisms with nuclei — with a skeleton made up of numerous glass-like needles woven together.
Other creatures collected include an unusually long deep-sea polychaete worm, a variety of copepod crustaceans, as well as monoplacophoran limpets.