Jaws IV: Algae takes on CO2

Scientists at PNNL's Marine Sciences Laboratory in Sequim, Wash., are looking at marine algae as a solution to global warming caused by carbon dioxide emissions from fossil-fuel-fired power plants.

Marine micro algae are bacteria that take up carbon dioxide during photosynthesis in a process called biofixation. During biofixation, micro algae transform fossil carbon dioxide into algae cell mass.

Scientists envision pumping carbon dioxide that would have gone through a smokestack into big outdoor ponds containing micro algae, converting the greenhouse gas into algae biomass. "One of the options for disposing of the algae is to produce renewable fuels that could be used in place of fossil fuels," said Michael Huesemann, environmental research engineer at MSL. "This would create a closed carbon cycle where the carbon dioxide released from the combustion of algae-derived fuels would be fixed again by micro algae via photosynthesis, resulting in no net greenhouse gas emissions."

Huesemann and his colleagues are experimenting with algae species from as far away as Hawaii and Italy to find the algae with the highest growth rate and those that convert carbon dioxide into biomass most efficiently.

The scientists' goal is to develop a mathematical model to predict how algae will perform in outdoor ponds based on laboratory measurements of specific parameters, such as growth rate and photosynthetic yield. "It's much more efficient to plug specific parameters into a model and run it for different conditions like temperature and light intensity than to study 20 different outdoor ponds," Huesemann said.