From Farmer to Shrimper: The Dead Zone
(pg 3 of 8)
Nutrients, primarily nitrogen, carried by the
Mississippi fuel the growth of algae in the inshore
areas of the Gulf. Average concentrations of
nitrate in the Mississippi and some of its
tributaries have increased several times over since
the early 1900s. Overall, the amount of nitrogen
delivered to the Gulf via the Mississippi has
tripled since the late 1950s (mostly from the 1960s
to the early 1980s).
These huge increases in nitrogen have fertilized
ever larger growths of algae, contributing to
larger dead zones.