“Scientists say the summer “”dead zone”” in the Chesapeake Bay has grown to its usual size. Dead zones are areas in the bay where oxygen levels are too low to sustain fish and shellfish. The University of Maryland Center for Environmental Science took samples recently and found that the volume of oxygen-deprived water is typical for this time of year. The samples defied predictions that the dead zone would be smaller this spring because of low rainfall in parts of Pennsylvania and New York that drain into the Susquehanna River. Scientist William Dennison says it looks like heavy rains in Maryland and Virginia offset the reduced flow from the Susquehanna. Dead zones are created when sewage, air pollution and fertilizer runoff spur algae growth in the water.”