Hypoxia occurs when dissolved oxygen falls below the level necessary to sustain most animal life, often due to fertilizer run-off. This volume reviews how the expanding hypoxic zone in the northern Gulf of Mexico has affected living resources in the Louisiana/Texas shelf. Topics of the 23 chapters include impacts of changing Si/N ratios and phytoplankton species composition, the effect of hypoxia and anoxia on the supply and settlement of benthic invertebrate larvae, and ecological effects of hypoxia in fish, sea turtles, and marine mammals. Annotation c. Book News, Inc., Portland, OR (booknews.com)