Viruses against climate change? Last April, a team of scientists revealed that in the samples collected aboard the French sailboat Tara, they had identified more than 5,500 types of RNA viruses — viruses whose genetic material consists of ribonucleic acid, as opposed to viral DNA.
The researchers then suggested that some of these viruses could play an important role in the marine ecosystem. Their new study, published in the prestigious journal Science (9/6/2022), specifically addresses this hypothesis.
5,500 new viruses discovered in the oceans
The oceans capture 30% of the carbon dioxide (CO2) emitted into the atmosphere by human activities (CNRS, 2021), a greenhouse gas that contributes to global warming. As such, the marine environment is one of the most important natural “carbon sinks” on Earth.
While CO2 largely dissolves in the water in the form of carbon dioxide, the “carbon pump” is also performed by phytoplankton, i.e. all microscopic algae that are present on the surface. Thanks to the energy provided by sunlight, which is used for photosynthesis, phytoplankton will grow and multiply. In doing so, it stores carbon in the form of organic material, some of which eventually sinks to the bottom of the oceans.
However, by infecting marine organisms whose cellular machinery they use to reproduce, certain viruses are likely to influence this storage process.
Which virus infects which host?
The scientists tried to determine the marine species that hosted the discovered viruses. One of the methods was a genetic analysis: in fact, viral genetic material can integrate”accidentally” in the genome of the infected organism.
†When this happens, that’s a clue, because if you find a ‘signal’ from a virus in a host’s genome, it means the virus was present in the cell at some point.Guillermo Dominguez-Huerta, the lead author of the study, explains, quoted in a press release.
Bottom Line: While most DNA viruses infect bacteria, which are abundant in the ocean, RNA viruses primarily infect aquatic fungi and unicellular eukaryotes (organisms composed of a single cell, equipped with a nucleus) – one of which is the phytoplankton, which sequesters carbon , is a part.
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More specifically, about 1,243 species of RNA viruses have been associated with ocean carbon storage, at least 11 of which are said to have a particularly significant impact on this process by infecting hosts that, upon death, sink to the bottom of the ocean. the ocean. the sea, through which organic matter is retained.
The ocean facing climate change
So, according to Matthew Sullivan, professor of microbiology at the scientific reference of the study at the State University of Ohio (United States), certain RNA viruses would probably function as “tests“controlling carbon sequestration in the oceans.
†As humans release more carbon into the atmosphere, we depend on the ocean’s massive buffering capacity to slow climate change.” the researcher insists in a press release.
The study authors emphasize the importance of their results for the development of models aimed at simulating the carbon cycle on the planet. Models with which we can anticipate the magnitude of climate change and its consequences.
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Did you take a photo that illustrates the warming of our climate? So, before July 14, 2022, take part in season 2 of the photo contest “L’Oeil du Climat” on the theme: “Climate change in France”, organized by GEO with Météo-France.
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