For geochemist Beverly Johnson, shells tell a story
Organic gardeners know that eggshells, despite their brittleness, are durable, because they’re still recognizable in the compost heap when all else has turned to humus.
Organic geochemist Beverly Johnson knows that an eggshell can endure even for tens of millennia. Moreover, that shell can reveal much about the world in which it was made.
Eggshells are especially useful to Johnson, who has been an assistant professor of geology at Bates since January 2001 and who specializes in relating organic substances from the geological record to long-term environmental change.
Combined with the eggshell’s longevity is the fact that a bird’s diet leaves chemical traces in the shell she lays. Chemical variations from one batch of eggs to another can indicate much about environmental alterations over time. [More...]