Crew members pull an oyster dredge in Tangier Sound of the Chesapeake Bay near Deal Island, Md., in 2013. A study found that the Chesapeake Bay shellfishery is a "hot zone" for ocean acidification. Patrick Semansky/AP hide caption

itoggle caption Patrick Semansky/AP

Cannonball jellyfish soak up the sun on a South Carolina beach. Fishermen are now pursuing the pest that used to clog their shrimping nets. Courtesy of Steven Giese hide caption

itoggle caption Courtesy of Steven Giese