What would a radioactive ocean cause to our world?

From CNN: "the fuel can spill out of the damaged containment unit and spread radioactivity and cancer-causing isotopes through the air and water." So say this situation happens to an ocean, what would happen to all the marine life? Could there be a catastropic chain of events that could effect the circle of life due to a radioactive ocean? Even if the crisis in japan is handled, every power plant is created near a large body of water of some sort, so this could be a problem of the future as well.