Four new species of giant single-celled organisms discovered on the Pacific seabed

Two new genera and four new species of giant single-celled xenophores (protozoa belonging to a group called foraminifera) were discovered in the deep Pacific Ocean during a joint project between scientists at the National Center for Oceanography, UK (NOC), the University of Hawai’i and the University of Geneva. ‘Moana’ has inspired the name Moanammina for one of the new genres, while the second has been named Abyssalia in recognition of its abyssal habitat.

Species were described, based on morphology and genetic data, from specimens collected with the University of Hawaii Lu’ukai remotely operated vehicle on an expedition to the western Clarion Clipperton Zone (CCZ) aboard the RV Kilo Moana in 2018. The seabed in this area is over three miles deep. The CCZ occupies a vast swath of the Pacific Ocean with extensive deposits of polymetallic nodules on the sea floor and is intended for deep-water mining.

“We were excited to find these beautiful new xenophophors,” said Andrew Gooday, professor at NOC and lead author of the recently published findings. “It seemed appropriate to name one after ‘Moana’, a Hawaiian word meaning ocean. Xenophophores are one of the most common types of large organisms found in the abyssal plains of CCZ, so the second genus name was chosen. to reflect this. “

Like some other types of foraminifera, xenophophors build shells, called tests, made up of particles they obtain from the surrounding environment. These are elaborate structures that can reach sizes of four inches or more.

Moanammina semicircularis sp. Nov., the new species of the new genus, has a stalked fan-shaped test, about three inches tall and three and a half inches wide. Two other new species, Abyssalia foliformis sp. Nov. and Abyssalia sphaerica sp. Nov., it has evidence that resembles a flat sheet and an almost perfect sphere, respectively. They are notable for being constructed entirely of glass sponge spicules. The fourth new species is Psammina tenuis sp. nov., which has a delicate, thin, plate-shaped test.

“These four new species and two new genera have increased the number of xenophophors described in the CCZ chasm to 17 (22% of the global total for this group), with many more known but not yet described,” Gooday said. “This part of the Pacific Ocean is clearly a critical point of xenophiophor diversity.”

“The abundance and diversity of these giant single-celled organisms is truly amazing!” said oceanographer Craig Smith of the UH Mānoa School of Ocean Science and Technology (SOEST), co-author and chief scientist of the RV cruise ship Kilo Moana in which the xenophophors were discovered.

“We see them everywhere on the seafloor in many different shapes and sizes. They are clearly very important members of the rich biological communities that live in the CCZ. Among other things, they provide microhabitats and potential food sources for other organisms. We need to learn much more about the ecology of these strange protozoa if we want to fully understand how deep sea mining could affect these deep sea communities. “

Moanammina semicircularis It is genetically identical to another specimen found in 2017 in eastern CCZ. Therefore, this study provided the first genetic confirmation of wide geographic ranges (at least ~ 2,300 miles) for a species of abyssal xenophophore.