Large numbers of fungi have been found living in the ocean’s twilight zone, which could open the door to new drugs that could rival the power of penicillin.
The largest ever study of ocean DNA, published by the journal Frontiers in Science, has revealed intriguing secrets about the abundance of fungi in the part of the ocean just beyond the reach of sunlight. At depths between 200 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, luminous skin.
“Penicillin is an antibiotic that originally comes from a fungus called Penicillium so maybe we’ll find something like that from these ocean fungi,” says 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 exhibit unique adaptations,” he added. “This could potentially lead to the discovery of new species with unique biochemical properties.”
The new ocean DNA catalogue, launched Tuesday, contains more than 317 million gene groups for marine organisms, compiled from samples collected during voyages including the four-year Tara Oceans Expedition that started in 2009, and the 2010 Malaspina Circumnavigation expedition.
Technological advances meant that existing samples could yield much more data than before, while the process of cataloging helped open new doors to the underexplored ocean, said marine biologist and lead author of the paper, Elisa Laiolo.
The marine biotechnology sector, which depends on ocean organisms and their genes, is worth an estimate $6 billiona figure that is expected to almost double by 2032.
Laiolo was surprised to see so many fungi living in the ocean’s twilight zone. “There have been indications before (abundance of fungi at this level), so this is another piece of the puzzle.”
Another crucial discovery made during the cataloging process, said Carlos Duarte, professor of marine sciences and senior author of the study, was the role viruses played in increasing gene diversity. “The viruses insert themselves and move genes from one organism to another. This means that viruses create genomic biodiversity and that accelerates their evolution.”
One result of that acceleration, he said, was genes that had evolved to allow organisms to chew through plastic. “They can break down synthetic polymers derived from hydrocarbons, which are very recent pollutants in the ocean, showing that evolution has occurred over a few decades.”
The catalog also revealed gaps in our understanding of the ocean floor, Laiolo said. “It is easier to take water samples than the ocean floor and what we underline in the article is the need to do more research on the sea floor in the future.”
Developments in supercomputing and sequencing technologies mean that more information can be extracted from existing samples, at much lower costs.
Despite the catalog’s benefits, Duarte said there were problems with owning marine genes and sharing the benefits, especially with countries in the global south that did not have the same access to gene sequencing and analytical supercomputing. “Currently, 10 countries own 90% of marine gene patents, and the benefits are not shared,” he said.
However, changes are being made to the ownership rules. “Since October last year, a new treaty has come into effect saying that those who discover a marine gene possess it.” Duarte said. “But they have to share the benefits. The problem is that it is not clear how that distribution of benefits will work.”
The publication of the catalog was welcomed by marine scientists. Favoretto described it as a “remarkable resource for biodiversity assessment and conservation efforts” that would allow researchers to monitor changes in species distributions, especially in relation to the impact of the climate crisis and human activities.