Some species of marine phytoplankton, such as the prolific bloomer Emiliania huxleyi, can grow without consuming vitamin B1 (thiamine), researchers have discovered. The finding contradicts the common view that E. huxleyi and many other eukaryotic microbes depend on scarce supplies of thiamine in the ocean to survive.
"It's a really different way to think about the ocean," says CIFAR Senior Fellow Alexandra Worden, co-author on The ISME Journal paper with CIFAR fellows John Archibald (Dalhousie University), Adrin Reyes-Prieto (University of New Brunswick) and three lead authors from Worden's lab at the Monterey Bay Aquarium Research Institute, Darcy McRose, Jian Guo and Adam Monier.
All living creatures need thiamine to live, as well as other vitamins. Organisms may produce some of their own vitamins, the way that human cells create vitamin D with help from sunlight, but sometimes they rely on other organisms to produce the vitamins they need and then consume them. For example, oranges and other fruits produce vitamin C, which humans need in their diets.
Until now, many marine microbes with cells that have a nucleus eukaryotes were thought to depend on other organisms to produce thiamine. If this were the case, B1 would be a major factor in controlling the growth of algae such as E. huxleyi, whose blooms are sometimes so large you can detect them from space. But the researchers found that E. huxleyi grows equally well in water that contains a precursor chemical to thiamine, known as HMP, as it does in an environment rich with thiamine. In fact, it could grow without any thiamine at all.
"If we added thiamine or we added the intermediate, there was absolutely no difference in the
|Contact: Lindsay Jolivet|
Canadian Institute for Advanced Research