The Earth our home is covered mostly with water: the wide, deep, salty, and very blue ocean. It regulates our climate in a way that makes life as we know it possible. This huge ocean is full of an amazing amount of life, most of which is too small to see. But life in the ocean is in trouble. The ocean is becoming hotter, more polluted, and, in places, empty of life. The right amount of warming is good for us, but too much warming is causing shifts...