Sunday, December 13, 2009

Algae – a new tool in the global warming fight?

Well, I am a bit behind in my postings. There are just so many events that we are engaged each day/night until we collapse on the train home! I will hopefully catch up a bit today.
Having done research on algae since 1981, I, of course, had to go to the session sponsored by the Bellona on algal research related to addressing climate change issues. So this post will be a bit more technical than most of my others ones. But – I think you will still find it interesting.
A bit of background: While thought of by some as “pond scum”, algae are pretty remarkable in their ability to grow in all sorts of environments; they grow fast; and they are incredibly important in the food chain, especially in the ocean. On a global basis, they play a “mega role” as carbon absorbers. But they also play an important commercial role in cosmetics, food supplements, nutraceuticals, colorings, toothpaste, sushi, etc. When algae are grown under different conditions, they tend to produce a variety of cellular products. So, for instance, you can grow them to have high protein content or under a different set of conditions to get a high lipid content. In other words, they could be either a food supplement or a potential biodiesel source. Some even produce hydrogen gas (under anaerobic conditions) or extremely high levels of sugars—which can be turned into ethanol. Thus, for some time, there has been interest in algae as a potential fuel source, but a range of technical issues in scaling up processes remain a problem. In addition, anyone who has maintained algal cultures knows that contamination with bacteria or other algal species can be a problem.
Some facts from the panel: Currently, the 3 main sources used for biofuel production: soybean, canola and palm oils. The yields are about 50, 160 and 600 gallons/acre/year, respectively according to one of the presenters. The rush to biofuels is leading to the fuel vs. food debate and even more rapid deforestation to create space for more oil-crops. Algae, on the other hand, would be grown aquatically, and thus, wouldn’t compete for land use, and it is estimated that the yields could be around 2000 to 5000 gallons/acre/year. Another way to think about this is that if you were to grow soy just for jet fuel, the entire area of Europe would need to be planted. If you used algae as the source, only an area the size of Belgium would be needed.
There are bioreactors that can be used to grown algae vertically but scale up is difficult. I was surprised to learn of the work with sugar kelp (a species of Saccharina) along the coast of Norway and the interest in the kelp forests by the Scandinavian research group SINTEF. The latter is a brown algae – Laminariale. These grow at a rate of about 18% a day!
The aviation industry is very interested in biofuel research. They have tested flights with biofuels and are close to receiving certification to begin using these more routinely. Of the American airlines, Continental and Jet Blue are involved.
This all sounds rather optimistic, but I question some aspects. Algae don’t just need carbon dioxide and sunlight. They need nitrogen and phosphorous as do other plants and we cannot simply dump large amounts of these nutrients into oceans. Anyone with a bit of ecology background knows the problems that occur when excess nutrients are added to waterways. Large scale aquaculture of kelps and other large algae could have unforeseen ecological impacts in terms of changes in biodiversity. The presenters made it sound that all of this was new, but I remember these conversations back in the 1980’s. One of the topics back then was how do you supply iron to the algae (an important micronutrient) but this wasn’t mentioned in the session I attended. Back in the 80’s there was even talk of the “Geritol” solution to excess carbon in the atmosphere. That is, if we add iron to the oceans, algae growth could rise dramatically and act as even a bigger sink for carbon!

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