Despite the theories of so-called scientists, the vast quantities of water on this planet and on other planets are not created by a mixture of hydrogen and oxygen. Rather, the water is sometimes explained to be the perspiration and sometimes the semen of the Supreme Personality of Godhead. It is from water that all living entities emerge, and because of water they live and grow. If there were no water, all life would cease. Water is the source of life for everyone. Therefore, by the grace of the Supreme Personality of Godhead, we have so much water all over the world.
Source: A.C. Bhaktivedanta Swami Prabhupada (2014 edition), “Srimad Bhagavatam”, Ninth Canto, Chapter 5 – Text 5 & Introduction