R&D Magazine published an article on their website on April 7th describing some very interesting work underway at the US Naval Research Laboratory (NRL) Materials Science and Technology Division. They “have recently demonstrated proof-of-concept of novel NRL technologies developed for the recovery of carbon dioxide (CO₂) and hydrogen (H₂) from seawater and conversion to a liquid hydrocarbon fuel.” They went on to demonstrate the viability of the fuel by using it to fly a model airplane. All this is very interesting and very important to the ongoing concerns of the buildup of man produced (anthropogenic) CO₂, and the related issues of global warming and ocean acidification.

Most of the press we are exposed to relating to mankind’s increasing release of CO₂ from fossil fuel consumption ties it to atmospheric driven global warming and all the associated problems. However, another result effectively described on the US Department of Commerce—National Oceanic and Atmospheric Administration (NOAA) Pacific Marine Environmental Laboratory (PMEL) web site is the concern over the gradual decrease in pH in the ocean. The drop in pH (increase in acidity) is caused by water’s ability to absorb CO₂ and the resulting carbonic acid that is produced. The NOAA-PMEL, National Geographic and other sources state that of all the CO₂ produced by fossil fuel consumption, the oceans absorb 25%–50%. The remaining amount may be consumed by plants, or may end up in the atmosphere or elsewhere.

The drop in pH of the ocean, reported to be accelerating since the beginning of the industrial revolution and its associated increase in fossil fuel consumption, could have a significant negative effect on the marine ecosystem. We would expect to see significant effects on corals, crustaceans and mollusks, on vertebrates such as fishes and on echinoderms like starfish and sea urchins. Naturally, all other species that relied on them for food would also be affected, including man.

Some of these consequences can be substantiated by looking at ocean sediment from 55 and 250 million years ago when there were also increased levels of CO₂ in the ocean from volcanic activity. Also, there are some specific localized shallow ocean waters near volcanoes that can be studied today, where CO₂ is released into the water from underground sources. These locations have demonstrated many of the negative effects we may see if the ocean’s pH continues to fall.

So if we step back and dream about the further development of the work started by the NRL, is there a glimpse of a sustainable solution in there somewhere? If we can “harvest” CO₂ from the ocean and use it to produce a liquid hydrocarbon fuel, when that fuel is consumed, it again produces some CO₂, a portion of which gets reabsorbed back into the ocean. It isn’t a perfect closed loop, but together with real efforts to reduce our use of fossil fuels, it might be a path towards improvement. Obviously, there is much more work to be done, but the article in R&D seems optimistic and one might imagine that in the eventual processing of copious quantities of sea water, there will be opportunities for filtration and separation technologies to play an important role.

Contact Keith B.