Element of the month: Meteoric calcium

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Calcium is one of the most abundant elements on Earth. It plays various roles in many organisms, whether for the contraction of muscle cells, preserving potential differences across membranes, as a co-factor for some enzymes, or a component of bones and shells, to name a few.

Yet, it is surprisingly scarce in the upper atmosphere. Why could that be? Don’t anxiously skip to the end of this post for the answer… this scarcity remains unexplained for now. In this month’s ‘in your element’ article (subscription required) John Plane, Professor of Atmospheric Chemistry at the University of Leeds, ponders on this mystery.

All of the calcium that is present in the upper atmosphere has actually been brought there by interplanetary dust particles entering the Earth’s atmosphere, in a process called ‘meteoric ablation’. The intriguing data is that the concentration of calcium is much lower than expected — about 200 times lower than that of sodium for example, whereas they are present in roughly the same concentrations in the Earth’s crust. Check out the article to find out how scientists measure metal concentrations in the atmosphere.

Could the interplanetary dust particles be depleted in calcium before they even come in contact with our atmosphere? Could it be that more volatile elements (such as sodium) get ablated from the meteorites much more easily than calcium? Or an effect of a peculiar atmospheric reactivity for calcium? Plane explains how some of these reasons are valid, but only to some extent — and so the depletion in calcium has not yet been entirely accounted for.


Anne Pichon (Associate Editor, Nature Chemistry)

Anne Pichon

Senior Editor, Nature Chemistry, Springer Nature

Anne received a broad training in chemistry at the National Graduate School of Chemistry in Montpellier, France. She then focused on inorganic and supramolecular chemistry and obtained her MPhil and PhD degrees from the Queen's University Belfast, UK, investigating porous coordination polymers for host–guest applications. After an internship with Nature Reviews Drug Discovery, Anne moved to John Wiley and Sons in 2007 as an assistant editor of the Society of Chemical Industry journals. She joined Nature Chemistry in October 2008, and was initially based in Tokyo where she also worked on other publishing projects with Nature Asia-Pacific. In April 2013, Anne relocated to the London office and now works full time on the journal.