The application of marine microalgae

Food and fuel are becoming limiting. microalgae seem to be a possible solution to both problems. Algae need far less space compared to land plants. But if they show such great potential why don't we all eat algae and use fuels derived from algae? Open ponds are a cheap and relatively easy way to culture algae. But only extreme algae can be cultured this way and therefor open systems are limited to a few species. Bio-reactors have far more control and a larger range of algae to be cultured. Costs are often limiting but a lot of research is being done to optimize closed systems. They show great potential for future algal culturing. It is unlikely microalgae will become our main food source due to high costs. But in time fuel derived from algae should be able to compete with fossil-fuels.