OCEANS:
An ocean (from Greek Ωκεανός, Okeanos (Oceanus)) is a major body of saline water, and a principal component of the hydrosphere. Approximately 71% of the Earth's surface (an area of some 361 million square kilometers) is covered by a continuous body of water that is customarily divided into several principal Oceans and smaller seas.

More than half of this area is over 3,000 meters (9,800 ft) deep. Average oceanic salinity is around 35 parts per thousand (ppt) (3.5%), and nearly all seawater has a salinity in the range of 30 to 38 ppt.

Less than 2% is fresh water, the rest is saltwater, mostly in the ocean.
Seven Oceans- Indian, Arctic, Antarctic, North-South Pacific, North-South Atlantic.

TDS:
Total Dissolved Solids – are the total amount of mobile charged ions, including materials, salts or metals dissolved in a given volume of water, TDS, which is based on conductivity, is expressed in parts per million (ppm) or milligrams per liter (mg/L). TDS includes any conductive inorganic element present others than the pure water molecules (H2O) and suspended solids.

TDS affects everything that consumes, lives in or uses water, from fish and plants to plumbing and laboratories.

For people, the lower the TDS level in the water you drink, the more efficiently your body’s cells are hydrated. The higher the TDS level in the water, the greater the probability of harmful contaminants that can pose health risks or hinder the absorption of water.