Abstract
Ulva is a ubiquitous marine macroalgal genus, the opportunistic growth of which can largely be explained by its ability to switch between two modes of photosynthetic inorganic carbon (Ci) acquisition. In cold climates, the less efficient, external carbonic anhydrase- (CA) catalysed HCO3- to CO2 conversion mechanism prevails. However, when transferring such “CA-state” thalli to the warmer and higher-irradiance conditions conducive to high photosynthetic rates (such as found in tropical areas), a for macroalgae unique, highly efficient, form of an anion-exchange- (AE) mediated HCO3- uptake system takes over. The following topics will be discussed in a historical perspective: • Ways of Ulva to utilise external HCO3- for its photosynthesis. • Is there a need for a CO2 concentrating mechanism (CCM)? If so, • Is Ulva a C4 alga? • The rare ability of Ulva to increase pH values (to >10) in enclosed areas and, thus, prevent other, CA-state, macroalgae from growing in such habitats. • The ability of intertidal Ulva to photosynthesise when emergent.
Bio
Sven Beer is originally from Sweden, where he completed his BSc in Biology at Stockholm and Uppsala Universities. After moving to Israel in 1973, he graduated with a PhD (title of dissertation: ‘Photosynthesis of Marine Angiosperms’) from Tel Aviv University, where he has worked ever since. He is now an Emeritus Professor at that university, and also holds an affiliated professorship at Stockholm University. During his career, Sven has authored some 130 papers in the field of marine botany and, especially, photosynthesis of marine macrophytes.
Sven’s home page is https://en-lifesci.tau.ac.il/profile/svenb
