A newly discovered group of algae

Copyright © Kim, Harrison, Sudek et al. PNAS 201

A newly discovered group of algae living in both fresh water and oceans may have worldwide distribution.

A team of biologists has discovered an entirely new group of algae living in a wide variety of marine and freshwater environments.

This group of algae, which the researchers dubbed "rappemonads," have DNA that is distinctly different from that of other known algae. In fact, humans and mushrooms are more closely related to each other than rappemonads are to some other common algae (such as green algae).

Based on their DNA analysis, the researchers believe that they have discovered not just a new species or genus, but a potentially large and novel group of microorganisms.

The rappemonads were found in a wide range of habitats, in both fresh and salt water, and at temperatures ranging from 52-79°F.

According to MBARI Senior Research Technician Sebastian Sudek, co-first-author of the paper reporting the discovery of these algae: "Based on the evidence so far, I think it's fair to say that rappemonads are likely to be found throughout many of the world's oceans. We don't know how common they are in fresh water, but our samples were not from unusual sources – they were from small lakes and reservoirs."

Researchers Sebastian Sudek, Heather Wilcox, and Alexandra Worden of the Monterey Bay Aquarium Research Institute (MBARI), along with collaborators at Dalhousie University and the Natural History Museum (NHM), London, discovered these microscopic algae by following up on an unexpected DNA sequence listed in a research paper from the late 1990s.

They named the newly identified group of algae 'rappemonads' after Michael Rappe, a professor at the University of Hawaii who was first author of that paper.