Low oxygen levels, coral bleaching getting worse in oceans

In this 2010 photo provided by the Smithsonian Institution, corals and crabs lie dead from low oxygen in Bocas del Toro, Panama. A study released on Thursday, Jan. 4, 2018 finds that oxygen levels dropping in the world’s oceans, choking large areas, is worsening and more of a complex problem than previously thought. (Arcadio Castillo/Smithsonian via AP)This 2017 photo provided by NOAA shows bleached coral in Guam. A study released on Thursday, Jan. 4, 2018 finds that severe bleaching outbre