Marine Phytoplankton May Not Need All Its Vitamins to Grow

It turns out that some species of marine phytoplankton don't need all of their vitamins to grow. Scientists have found that some species can grow without consuming vitamin B1 (thiamine), which contradicts the common view that many eukaryotic microbes depend on scarce supplies of this vitamin in the ocean to survive.

All living creatures need thiamine and other vitamins to live. While organisms may produce some of their own vitamins, they also rely on other organisms to produce the vitamins they need and then consume them. For example, humans rely on oranges and other fruits for vitamin C. That's why researchers believed that many marine microbes were dependent on other organisms to produce thiamine.

Yet it appears that this isn't the case. It turns out that Emiliania huxleyi, a prolific bloomer, can grow without thiamine. The scientists conducted a genetic analysis, which revealed 31 new eukaryotic riboswitches, which are segments of RNA that operate like mechanical switches to turn genes on or off. In addition, the scientists found that the riboswitches were tied to genes of unknown function rather than genes connected with the production of thiamine.

"If we added thiamine or we added the intermediate, there was absolutely no difference in the growth rate. They were growing equally well," said Alexandra Worden, one of the researchers, in a news release. "Our study shows that conclusions regarding the importance of vitamin B1 in regulating algal communities need to be re-evaluated."

The findings reveal that B1 is far less important than previously thought. This has implications when it comes to modeling production and the global carbon cycle, which is more important than ever in the face of climate change.

The findings are published in The ISME Journal.