New paper in Science Advances explores gravitational sinking in unicellular algae


Unicellular algae are the main primary producers in the ocean, collectively being responsible for about half of the globally fixed carbon dioxide. Because they need access to light, they must counteract gravitational sinking, which would take them out of the sunlit ocean.

How algae regulate gravitational sinking is poorly understood. In a collaboration with researchers at the Massachusetts Institute of Technology, the Polz group at DOME shows in a paper in Science Advances that sinking depends on cell size, light and nutrient concentration. Some algal species sink faster when starved for nutrients due to accumulation of cellular carbohydrates and loss of water, both of which increase their density. This is ecologically significant since deeper water into which they sink contains more nutrients, potentially leading to a recharge in nutrients and resumed growth.




Picture showing algal cells in blue, green, red and yellow on black background

Tetraselmis sp. cells with cellular proteins labeled as red/yellow, DNA labeled as green, and chloroplasts labeled as blue © Teemu Miettinen