There has been a good deal of interest in the potential of marine vegetation as a sink for anthropogenic C emissions ( Blue Carbon ). Marine primary producers contribute at least 50 of the world s carbon fixation and may account for as much as 71 of all carbon storage. In this paper, we analyse the current rate of harvesting of both commercially grown and wild-grown macroalgae, as well as their capacity for photosynthetically driven CO2 assimilation and growth. We suggest that CO2 acquisition by marine macroalgae can represent a considerable sink for anthropogenic CO2 emissions and that harvesting and appropriate use of macroalgal primary production could play a significant role in C sequestration and amelioration of greenhouse gas emissions. A? 2010 Springer Science+Business Media B.V.