The Mobile Bay Jubilee: Background information when reading The Lives of Rocks

The Mobile Bay Jubilee

This article relates to The Lives of Rocks

In "Titan" a man recalls a boyhood vacation spent on the coast of Alabama in which he experiences a "Jubilee".Jubilee is a natural phenomena that occurs in Mobile Bay from time to time, usually before dawn on a warm summer night, when large numbers of fish, crabs and shrimps swarm close to shore, making themselves easily available to locals who come out with all sorts of containers and scoop them up in quantity.

Jubilee appears to be caused by the natural stratification of the Bay waters, with the heavier saltwater beneath and the lighter fresh water on the top. When the Mississippi River dumps an unusually high amount of fresh water into the bay (i.e. after heavy rains), it also dumps large amounts of nitrogen, which in turn promotes the growth of algae and zooplankton, which eventually sinks to the bottom where it decomposes, consuming available oxygen. The stratification of the fresh and saline water prevents the mixing of oxygen-rich water from the surface with the oxygen-depleted water below, causing a hypoxic (low oxygen) zone - this forces bottom dwellers, such as flounder, eel, crab and shrimp up to the surface in search of oxygen.

Filed under Nature and the Environment

This "beyond the book article" relates to The Lives of Rocks. It originally ran in January 2007 and has been updated for the October 2007 paperback edition. Go to magazine.