Eugene S. Takle
© 27 February 1998
A note under ScienceScope edited by Jocelyn Kaiser in Science (vol 274, page 331; October 1996) describes a vast area of oxygen-depleted (hypoxic) water in the Gulf of Mexico at the mouth of the Mississippi River. This hypoxic zone has been created by algal blooms produced by excess nutrients (nitrogen) from sewage and fertilizer runoff, perhaps as far away as the US Midwest. The dead plants sink and use up oxygen in the decay process at lower levels, thus reducing oxygen available for other marine organisms at these levels. This zone has area of about 18,000 square kilometers and may threaten fisheries in the area.