Free-ocean CO2 enrichment (FOCE) systems: present status and future developments

Free-ocean CO2 enrichment (FOCE) systems are designed to assess the impact of ocean acidification on biological communities in situ for extended periods of time (weeks to months). They overcome some of the drawbacks of laboratory experiments and field observations by enabling (1) precise control of CO2 enrichment by monitoring pH as an offset of ambient pH, (2) consideration of indirect effects such as those mediated through interspecific relationships and food webs, and (3) relatively long experiments with intact communities. Bringing perturbation experiments from the laboratory to the field is, however, extremely challenging. The main goal of this paper is to provide guidelines on the general design, engineering, and sensor options required to conduct FOCE experiments. Another goal is to introduce xFOCE, a community-led initiative to promote awareness, provide resources for in situ perturbation experiments, and build a user community. Present and existing FOCE systems are briefly described and examples of data collected presented. Future developments are also addressed as it is anticipated that the next generation of FOCE systems will include, in addition to pH, options for oxygen and/or temperature control. FOCE systems should become an important experimental approach for projecting the future response of marine ecosystems to environmental change.

The CO2 microalgae biorefinery: high value products and biofuels using halophilic microalgae in the “D-Factory”

Fuel-only algal systems are not economically feasible because yields are too low and costs too high for producing microalgal biomass compared to using agricultural residues e.g. straw. Biorefineries which integrate biomass conversion processes and equipment to produce fuels, power and chemicals from biomass, offer a solution. The CO2 microalgae biorefinery (D-Factory) is a 10 million Euro FP7-funded project which will cultivate the microalga Dunaliella in highly saline non-potable waters in photobioreactors and open raceways and apply biorefinery concepts and European innovations in biomass processing technologies to develop a basket of compounds from Dunaliella biomass, including the high value nutraceutical, β-carotene, and glycerol. Glycerol now finds markets both as a green chemical intermediate and as a biofuel in CHP applications as a result of novel combustion technology. Driving down costs by recovering the entire biomass of Dunaliella cells from saline cultivation water poses one of the many challenges for the D-Factory because Dunaliella cells are both motile, and do not possess an external cell wall, making them highly susceptible to cell rupture. Controlling expression of desired metabolic pathways to deliver the desired portfolio of compounds flexibly and sustainably to meet market demand is another. The first prototype D-Factory in Europe will be operational in 48 months, and will serve as a robust manifestation of the business case for global investment in algae biorefineries and in large-scale production of microalgae.