Large numbers of fungi have been found living in the twilight zone of the ocean, and could open the door to new drugs that might match the power of penicillin.
The largest ever study of marine DNA, published by the journal Frontiers in Science, revealed intriguing secrets about the abundance of fungi in the part of the ocean just beyond the reach of sunlight. At between 200 meters and 1,000 meters below the surface, the twilight zone is home to a variety of organisms and animals, including specially adapted fish such as lantern sharks and kite sharks, which have large eyes and glowing, bioluminescent skin.
“Penicillin is an antibiotic originally derived from a fungus called Penicillium so we might find something like this from these marine sponges,” said Fabio Favoretto, a postdoctoral researcher at the Scripps Institution of Oceanography at the University of California, San Diego. The twilight zone is characterized by high pressure, a lack of light and cold temperatures, providing an extreme environment “where fungi can show unique adaptations”, he added. “This could potentially lead to the discovery of new species with unique biochemical properties.”
The new marine DNA catalog, launched on Tuesday, contains more than 317 million gene clusters of marine organisms compiled from samples collected on voyages, including the four-year-old Tara Oceans Expedition which started in 2009 and the 2010 Malaspina Circumnavigation expedition.
Advances in technology meant that existing samples could provide far more data than before, while the process of cataloging helped open new doors to the understudied ocean, said marine biologist and the paper’s lead author, Elisa Laiolo.
The marine biotechnology sector, which relies on marine organisms and their genes, is worth an estimate $6 billiona figure expected to almost double by 2032.
Laiolo was surprised to see so many fungi living in the twilight zone of the ocean. “There were some indications of that [fungi abundance at this level] before, so it’s another piece of the puzzle.”
Another critical discovery made during the cataloging process, said Carlos Duarte, a marine science professor and senior author of the study, was the role viruses played in promoting genetic diversity. “The viruses insert themselves and move genes from one organism to another. This means viruses create genomic biodiversity and this accelerates their evolution.”
One result of that acceleration, he said, was genes that evolved to enable organisms to do this chew through plastic. “They can break down synthetic polymers derived from hydrocarbons that are very recently in the ocean as a pollutant, showing that evolution has occurred in a few decades.”
The catalog also highlighted gaps in our understanding of the ocean floor, Laiolo said. “It is easier to sample the water than the seabed and what we underline in the paper is the need to increase studies targeting the seabed in the future.”
Developments in supercomputing and sequencing technologies, she said, mean that more information can be gleaned from existing samples, at much lower cost.
Despite the benefits of the catalog, Duarte said there are problems with ownership of marine genes and sharing the benefits, particularly with countries in the global south that do not have the same access to gene sequencing and analytical supercomputers. “Currently 10 countries own 90% of marine gene patents, the benefits are not shared,” he said.
However, changes to ownership rules are being made. “Since October last year, a new treaty has come into effect that says those who discover a marine gene own it.” said Duarte. “But they have to share the benefits. The problem is that it is not clear how that benefit sharing will work.”
The release of the catalog was welcomed by marine scientists. Favoretto described it as a “remarkable resource for biodiversity assessment and conservation efforts” that will enable researchers to monitor changes in species distribution, particularly in relation to the impact of the climate crisis and human activities.
