Scientists discovered four new species of gigantic, single-celled xenophyophores (protozoans of the group called foraminifera) in the deep Pacific Ocean, according to a new study published in the journal Science Direct.
"Moana" inspired the name Moanammina for one of the newly-discovered genera, while the other was named Abyssalia for its abyssal abode.
Four new species discovered in deep Pacific
The discovery happened amid a joint project between the University of Hawai'i, the University of Geneva, and the National Oceanography Centre (UK, NOC). The new species were described based on morphology and genetic data retrieved from specimens gathered during the University of Hawai'i's Remotely Operated Vehicle Lu'ukai, during an expedition to the western Clarion Clipperton Zone (CCZ) aboard the RV Kilo Moana, in 2018.
The CCZ covers a vast area of the Pacific Ocean, with widely-distributed polymetallic nodule deposits — a place some say is ripe for deep-sea mining.
"We were excited to find these beautiful new xenophyophores," said Andrew Gooday, lead author of the recently published study and professor at NOC. "It seemed appropriate to name one after Moana', a Hawaiian word for ocean. Xenophyophores are one of the most common types of large organism found on the CCZ abyssal plains, so the name of the second genus was chosen to reflect this."
Similar to other kinds of foraminifera, xenophyophores build shells — called tests — made of particles amalgamated from the surrounding environment. These typically form into complex structures that grow to sizes of 10 centimeters (four inches) or more.
New species specs, tenuous deep Pacific habitat
The new species, called Moanammina semicircularis has a stalked and fan-shaped "test," is roughly 7.62 centimeters (three inches) tall and 8.9 centimeters (three and one-half inches) wide. Two additional species, Abyssalia sphaerica sp. nov. and Abyssalia foliformis sp. nov., both have tests that look like a near-perfect sphere and a flat leaf, respectively.
"These four new species and two genera have increased the number of described xenophyophores in the CCZ abyss to 17 (22% of the global total for this group), with many more known but still undescribed," said Gooday. "This part of the Pacific Ocean is clearly a hotspot of xenophyophore diversity."
They're both notable for being composed completely of glass sponge spicules. The fourth species is Psammina tenuis sp. nov., and has a delicate, thin and plate-like test.
"The abundance and diversity of these giant single-celled organisms is truly amazing!" said Craig Smith, an oceanographer from the UH Mānoa School of Ocean and Earth Science and Technology (SOEST), co-author and Chief Scientists of the RV Kilo Moana cruise which discovered the xenophyophores. "We see them everywhere on the seafloor in many different shapes and sizes. They clearly are very important members of the rich biological communities living in the CCZ," Smith added. "Among other things they provide microhabitats and potential food sources for other organisms. We need to learn much more about the ecology of these weird protozoans if we wish to fully understand how seafloor mining might impact these seafloor communities."
It's no controversy to say that many discoveries await us in the blue "frontier" of the deep Pacific. But the tantalizing possibilities of mining minerals may lead scientists to question naming the abyssal depths a "frontier" at all, in favor of preserving a tenuous habitat for a rich diversity of undiscovered species.