Of jingles, oysters and pearls

My collection of shells from beaches around Kodiak includes several 1- to 2-inch shells, which are round, thin, and resemble the rough and wavy ridges of an oyster shell. Sometimes these are found with both shells still attached to each other and reveal that the bottom shell is rather flat, molded to whatever substrate it grew on, and features a hole. The upper shell is deeper and looks like an oyster shell except that it is a bit rounder and thinner. While the outside is white to gray in color, the inside has a shiny, rainbow-colored layer of mother-of-pearl, which makes this small shell excellent for art and decoration projects. I’ve been told this shell is called a false oyster or jingle (for the sound it makes in a wind chime). Wikipedia claims that people also call them “mermaids’ toenails” and that they are related to oysters, but not in the same family as the edible oysters. The jingles are described as unfavorable and bitter to the taste (who would want to eat toenails?).

Over the last decade oyster farmers on the West Coast have been facing a new difficulty. Oysters are another early victim of ocean acidification. The increased concentration of carbon dioxide in the earth’s atmosphere resulting from the burning of fossil fuels since the beginning of the industrial revolution and our continuously high energy consumption results in more carbon dioxide being dissolved into the oceans. In seawater, carbo dioxide forms carbonic acid, making the water more acidic and lowering the pH. The acidity is bad news for shell-building organisms. Some oyster farms in Oregon have already seen all of their spat (young oysters) die when the intake water had a lower pH. I heard that one oyster farmer reported that the spat was not only dead, but that it was just gone — dissolved like the shell of an egg left in vinegar for a few days.

Switgard Duesterloh, Kodiak Daily Mirror, 27 May 2011. Full article.


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