Increasing Salp Populations Seen as Possible Natural Negative Feedback Mechanism

There has been a lot of talk about sequestering and storing the carbon dioxide emitted from coal plants, sometimes referred to by the term “clean coal” (an oxymoron?), but so far there has been little action. Nature, on the other hand, may really be stepping it up when it comes to carbon dioxide sequestering. Evidence comes from a report that salps, which are small jelly-like creatures that live in the ocean and survive by consuming algae, have increased markedly in abundance near Sydney, Australia since a salp survey was performed 70 years ago. The Sydney Morning Herald reports that the results of a recent marine survey found that the salps have increased in number by a factor of 10. Previously there have been reports of increasing salp populations off Antarctica. After the salps consume algae, which take in carbon dioxide from the atmosphere, the carbon dioxide eventually winds up on the ocean floor either in the feces from the salps or in the salps themselves after they die. Salps can consume tremendous amounts of algae because they reproduce very rapidly, in fact, more rapidly than any other multicellular organism. Their reproduction is so rapid that salps can double their population within a few hours.

It’s obviously too soon to know if salps are playing a role in stabilizing the climate. With global emissions of carbon dioxide still increasing about 3-4% per year despite knowledge on the implications of what this means for the planet it seems hard to believe that salps will matter. However, if because of political reasons we can’t stop global warming maybe the salp, with perhaps the most rudimentary of all nervous systems, can.

Explanation for End of Last Severe Global Warming Episode

The last time there was a severe global warming the episode, which was 55 million years ago, it may have been terminated by an increase in ocean plant life. The Discovery Channel news site reports that a team of scientists led by Adina Payton from the University of California at Santa Cruz arrived at this conclusion as a result of finding increased accumulations of barite (barium sulfate) in the ocean sediment. Barite forms when barium, which is in animal tissues, combines with sulfur. This reaction occurs when the barium saturates water, and therefore, when large amounts of dead plants have accumulated on the ocean bottom. The scientists published their findings in the journal Geology. The Discovery article quotes climate expert James Zachos, who was not a member of the research team, as saying that “this process is slow and thus lags the buildup of carbon in the atmosphere." Slow is right. According to Payton, the process of barium accumulation lasted for about 170,000 years. Nevertheless, the findings of this study might give a boost to proponents of schemes to sequester carbon dioxide by spurring the growth of algae or seaweed. Such schemes should even seem more attractive in the future if global efforts to reduce carbon emissions come up empty.