Natural algal population may explain how environmental changes affect global carbon cycles

October 9, 2017
Transmission electron microscopy image of Ostreococcus tauri strain RCC4221. Credit: Martin Hohmann-Marriott

Although they are invisible to the unaided eye, tiny green algae called Ostreococcus play a big role in how carbon, including carbon dioxide (CO2), cycle through our world. Researchers have sequenced and analyzed the complete set of genes (the genome) of 13 members of a natural Ostreococcus population. The analysis revealed that the O. tauri population is larger than anticipated. It's also diverse in terms of its genetics and appearance. The algae's natural resistance to ocean viruses influenced the algae's diversity.

Ostreococcus is a model species to study in marine environments. Though microscopic, these picoplankton use sunlight together with CO2 to create organic matter. The algae are significant primary producers (that is, they convert CO2 into biomass). Thus, the algae contribute to the . This study offers insights into the genetic variability of various Ostreococcus strains. The results will help scientists see how environmental changes affect algae's ability to survive and thrive.

Picophytoplankton such as Ostreococcus are so small they are invisible to the naked eye. Despite their size, their global abundance means they are a widespread primary producer and form the bases of several . In coastal areas, they account for as much as 80 percent of the available biomass. A decade ago, the Joint Genome Institute (JGI), a U.S. Department of Energy (DOE) Office of Science user facility, sequenced one of the Ostreococcus strains. That genome, along with other genome sequences from three groups of the picophytoplankton Ostreococcus, revealed the tiny algae's diversity and adaptation to different ecological niches around the world.

Now, a team led by researchers at the Oceanological Observatory of Banyuls, France, and including scientists at the DOE JGI, has resequenced and analyzed 13 members of a natural of Ostreococcus tauri from the northwest Mediterranean Sea. The analysis offers a complete picture on the surprisingly large population and correspondingly high genetic and phenotypic diversity within O. tauri species. The team identified two large candidate mating type loci, consistent with the pervasive evidence of recombination and thus sexual reproduction within the population. The work reported in Science Advances was enabled in part by the DOE JGI's Community Science Program. A deeper understanding of algal genomic diversity and potential will help scientists track carbon (and nitrogen) traffic through marine ecosystems as well as provide insights into the structure and operation of algal plant communities.

Explore further: Puzzling plankton yield secrets to role in evolution, global photosynthesis

More information: Romain Blanc-Mathieu et al. Population genomics of picophytoplankton unveils novel chromosome hypervariability, Science Advances (2017). DOI: 10.1126/sciadv.1700239

Related Stories

Virus reprograms ocean plankton

August 21, 2017

A virus which infects ocean plankton can reprogramme cells and change the way they absorb nutrients - potentially changing how carbon is stored in the ocean, new research shows.

What makes red algae so different and why should we care?

July 17, 2017

The red algae called Porphyra and its ancestors have thrived for millions of years in the harsh habitat of the intertidal zone—exposed to fluctuating temperatures, high UV radiation, severe salt stress, and desiccation.

Strong interaction between herbivores and plants

March 23, 2017

A research project conducted at the University of Cologne's Zoological Institute reveals important findings on the interaction between nutrient availability and the diversity of consumer species in freshwater environments. ...

Recommended for you

Heavy nitrogen molecules reveal planetary-scale tug-of-war

November 17, 2017

Nature whispers its stories in a faint molecular language, and Rice University scientist Laurence Yeung and colleagues can finally tell one of those stories this week, thanks to a one-of-a-kind instrument that allowed them ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.