Researchers in the United States have discovered a type of freshwater plankton that consumes only viruses in its diet – becoming the first ever organism to do so.
Sounds a little unusual? There’s more.
A lot of organisms consume viruses, some accidentally, some on purpose. But the microbe Halteria, a ciliate from the protist species, exclusively feasted on chloroviruses found in pond water. In the food chain, this is known as virovory.
Binge eating: The rate at which Halteria consumed the chlorovirus was also stellar. In two days, the organism’s population grew 15 times, and the viruses’ fell by a hundredfold.
Carbon impact? From this? Since chloroviruses “cause their hosts to burst apart”, carbon and other nutrients are released into the environment from their consumption.
Ecologist John DeLong at the University of Nebraska-Lincoln, where the research was conducted, said,
If you multiply a crude estimate of how many viruses there are, how many ciliates there are and how much water there is, it comes out to this massive amount of energy movement up the food chain. If this is happening at the scale that we think it could be, it should completely change our view on global carbon cycling.
More about the research: The research took a total of three years until this discovery was made in September 2022, and the paper published on PNAS.
The basic idea behind conducting this study was that viruses have amino acids, nucleic acids, lipids, nitrogen, and phosphorus, and are abundantly present in water, along with microorganisms. Someone might as well be eating them in that case.
So, the researchers used fluorescent green dye on chlorovirus DNA which was introduced in two types of plankton.
Turns out, they were right. However, Halteria was only an exception. Most microorganisms considered viruses a threat. One other organism that consumed viruses though was Paramecium, which snacked on them. Ugh!
What next? It still remains to be seen how this impacts the food web and the evolution of these species.