ANNAPOLIS, Md. (AP) — Chesapeake Bay dead zones are down this June from last spring when heavy rains pushed them to levels not seen in decades.

The Maryland Department of Natural Resources says samples collected in early June show 12 percent of the bay’s main stem had low oxygen levels, down from the same period last spring when a third had levels too low for life. The long-term average is 17 percent.

DNR says warmer, drier conditions this winter, compared to the extremely wet spring last year may be the difference.

Dead zones peak every summer as warmer, fresher water floats on top of deeper, saltier water. Summer heat and pollution also spur algae blooms that consume oxygen when they die and decompose.
(Copyright 2012 by The Associated Press.  All Rights Reserved.)