Cell and developmental biology of seaweeds

It was not plants but cyanobacteria and early eukaryotic algae that began oxygenation of the atmosphere billions of years ago. Today, algae in marine environments still account for a substantial proportion of global oxygen production, with estimates ranging from 50–70%.

Algae are a hugely diverse assemblage of organisms with different evolutionary origins. They range from microscopic, unicellular organisms to kelps that reach 10’s of meters in length. Although seaweeds are used for direct consumption (for example nori, used to wrap sushi) and source for extraction of valuable compounds (for example food thickeners), their use as a large-scale commodity is currently limited in Europe. Interest in seaweed cultivation is rapidly increasing as they are nutritious, do not compete for arable land, do not require fresh water and generally need no fertilizers. Given that more than 70% of the Earth’s surface is covered by oceans, seaweeds have the potential to contribute to our future food and biomass production. Our research focuses on the cell and developmental biology of seaweeds and aims to address fundamental biological bottlenecks that currently limit the scalability and profitability of the sector.

Our current research focuses on two groups of multicellular seaweeds: the brown and green seaweeds. Brown seaweeds evolved independently from the green lineage that contains land plants, green and red seaweeds, but show remarkably degree of convergence in organ and tissue differentiation. The kelp Saccharina latissima is a brown seaweed with high potential for seaweed farming in the waters of northwestern Europe. Its life cycle alternates between a microscopic and filamentous gametophyte and a macroscopic sporophyte that can reach meters in size. We investigate different cellular and developmental aspects, including the roles of the microbiome and polarly deposited cell wall components in morphogenesis. In a more applied setting, we aim to improve adhesion of seeding material to cultivation lines, which is the source of substantial losses and variation in yield.

We use the green seaweed Ulva compressa as a model system for multicellular chlorophyte seaweeds. From an evolutionary perspective, this group is interesting as an early representative of the green lineage that evolved multicellularity independently of land plants. Morphogenesis of U. compressa depends on interactions with specific microbial partners, which makes it an excellent system to identify mechanisms that drive development. 

The strong potential of seaweeds to contribute to future food and biomass production, combined with our surprisingly limited understanding of these organisms, provides plenty of reasons to deepen our understanding of this underexplored yet highly important group of organisms.