A new life form of tiny, cold-loving micro-organisms involved in photosynthesis has been discovered in the Arctic Ocean, according to an international team of scientists, including a Canadian researcher.

The tiny plant organism, called a picobiliphyte, is distinct from anything else in the ocean, according to Université Laval biologist and professor Connie Lovejoy.

The picture shows a picobiliphyta cell under a fluorescent microscope. The cell nucleus is coloured in blue, the cytoplasm in green and the plastide, which is responsible for photosynthesis, is coloured in red. The cell measures two by five micrometres.
(Fabrice Not/Station Biologique de Roscoff)

"It doesn't follow close to anything else we know about," said Lovejoy.

Picobiliphytes are plants containing fluorescent substances that glow under certain waves of light and are small enough to measure in microns — or millionths of a metre.

The discovery came after analyzing DNA sequences of vast amounts of micro-organisms in the ocean. European scientists discovered the peculiar micro-organisms off their shores, while Lovejoy did similar tests in the Canadian Arctic and found the same tiny life forms.

Their odd shape also separates them from typically round algae.

"When we first saw them under the microscope they looked like pieces of junk," said Lovejoy.

Almost absent in Mediterranean

Though the picobiliphytes are a relatively rare species of algae, they appear consistently in samples and are more common in the Canadian Arctic than in Europe, leading Lovejoy to suggest they might thrive in colder conditions.

They were almost completely absent from studies of Mediterranean waters, except for small amounts in winter.

Ocean plant life accounts for about half of photosynthesis, the biochemical process of converting carbon dioxide into oxygen using energy from the sun. Microscopic algae, or photoplankton, do most of the photosynthesis done in the ocean.

The tiny plants may also be a key part of the ocean food chain, said Lovejoy. She said the discovery underscores how little we know about the biodiversity of ocean life.

"Everything depends on everything else. If we don't understand all of the species at work and what they depend on [and] we play with something it could totally perturb the system," she said.