CBIOMES researcher contributes to study demonstrating that  pigment diversity in the cyanobacteria Synechococcus has enabled this organism to colonize all light environments.

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An international team of researchers has published a study in Science Advances on the distribution of the three main pigment types of the cyanobacterium Synechococcus in the global ocean. By analyzing variations in water color and ocean environmental conditions using a 3D simulation tool, the scientists demonstrate that this pigment diversity has enabled this organism to colonize all light environments.

Summary

• Synechococcus , one of the flagship species of phytoplankton, is among the most abundant photosynthetic organisms in the ocean and exhibits the greatest diversity of pigments.
• The Darwin global model, which simulates the functioning of the ocean, has made it possible to predict the distribution of the three main pigments of Synechococcus, the blue specialists, the green specialists and the chromatic acclimators.
• Synechococcus can colonize all light environments and thus increase the total biomass of its population.

Phytoplankton, microscopic algae essential to marine food chains, use pigments to capture light energy for photosynthesis. The quality and quantity of this light vary considerably in the marine environment, depending on coastal gradients, depth, and seasons, thus influencing the color of the water.

To adapt to these variations, phytoplankton organisms have developed a wide variety of light-capturing pigments. Some organisms, such as the cyanobacterium Synechococcus, have even developed a fascinating ability called “chromatic acclimation.” Like chameleons, this allows them to adjust their pigment composition according to the color of ambient light, thus optimizing the absorption of light energy. As one of the two most abundant photosynthetic organisms in the ocean and with the greatest diversity of pigments, Synechococcus is an ideal model for understanding how phytoplankton adapt to variations in water color.

In an article published in the journal Science Advances , researchers from the Laboratoire d’Océanographie de Villefranche (LOV), the Station Biologique de Roscoff (SBR), the University of Southampton and the Massachusetts Institute of Technology (MIT) study the distribution of the three main pigments of Synechococcus , namely blue specialists, green specialists and chromatic acclimators. To simulate the functioning of the world’s ocean, including spatio-temporal variations in water color, the scientists used MIT’s Darwin model, one of the most powerful 3D models in the world.

By integrating the light absorption properties of each of the Synechococcus pigment types into this model, they demonstrated that thanks to its remarkable pigment diversity, this organism can colonize all light environments, from blue to green, available in the marine environment, and thus increase the total biomass of its population.

This study highlights the importance of considering functional traits, such as pigmentation, to better understand the distribution of phytoplankton in the global ocean, particularly in the context of climate change, which modifies the color of the water and consequently, the light environment in which phytoplankton communities live.

Publication reference

Francesco Mattei, Anna E. Hickman, Julia Uitz, Louison Dufour, Vincenzo Vellucci, Laurence Garczarek, Frédéric Partensky, Stephanie Dutkiewicz (2025), Chromatic acclimation shapes phytoplankton biogeography, Science Advances, doi: 10.1126/sciadv.adr9609