In the game EARTH: save the ocean you clean the ocean simply by swiping and matching the corresponding colored bubbles. There are 3 items in the ocean you should avoid as they will make the game go faster if you grab them. But there also are 3 items you should try to grab because they will make the game go slower and thus make it easier to match the colored bubbles. This will extend your playing time and points, definitely try grabbing the +2 bubbles as they will double your points.
Keep playing the game to save the actual ocean as you will accumulate money for charity. The longer you play the more money will go to the good cause. A clean ocean is in your hands.