But the amount of water in the oceans does change over the long term.
Over the 'short term' of hundreds of years, the oceans' volumes don't change much. Of course, nothing involving the water cycle is permanent, even the amount of water in the oceans. Water is saline if it has a concentration of more than 1,000 ppm of dissolved salts ocean water contains about 35,000 ppm of salt. In this case, the concentration is the amount (by weight) of salt in water, as expressed in 'parts per million' (ppm). Saline water contains significant amounts (referred to as 'concentrations') of dissolved salts. The water in the oceans is saline (saltwater). It is also estimated that the oceans supply about 90 percent of the evaporated water that goes into the water cycle. That is about 96.5 percent of all Earth's water. Much more water is 'in storage' for long periods of time than is actively moving through the cycle. When we talk about the water cycle, we must consider both where water is stored in pools, and the fluctuation of water between those storehouses. The oceans contain the majority of all water on Earth - almost 97% of global water is stored in oceans.
