MOving ON WAter (MOONWAlk): Algae buoyancy LacKing limbs

The goal of MOONWALK is to understand how microalgae devoid of a motor move in water. Algae are photosynthetic, requiring ability to position themselves in their habitat so they can receive adequate light and nutrients for growth. Availability of these resources depend on how deep in the ocean an alga is placed. Several algae species have flagella, tiny arms used for swimming towards the light. However, numerous algae species contributing with >20% of global CO2 fixation don´t have flagella (defined as non-motile). So, how do they gain access to the most suitable habitat?

In response to different conditions, including the wavelength of incoming light and availability of nitrogen (N), many microalgae are able to accumulate vast amounts of lipids. The hypothesis of the MOOMWALK project is, that algae defined as non-motile move up and down in the oceans by changing their lipid content and thereby modulating their buoyancy. Thus, this project will study; what is the biological relevance of lipid accumulation in microalgae? Is there a conserved mechanism for diverse microalgae controlling the accumulation of lipids in non-favorable situations?

The lipid-derived altered algae buoyancy MOONWALK will be explored in a systematic approach, using five evolutionary distant algae species grown under three different stimuli for the identification of possible conserved mechanisms behind their oleaginous nature.

Knowledge gained will show 1) how production systems based on oleaginous algae can become more efficient, 2) how algae move to habitats suitable for growth, and 3) how algae has moved historically ending up on the sea bed becoming the starting point for fossil fuel deposits.