Salinity measurement of soluble salts can be found in salt water or brackish water. The ppt stands for part per thousand. The salinity of the world's oceans is 35 ppt, the freshwater is less than 0.5 ppt and the brackish water is in the range of 0.5 to 25. ppt. The salinity values ​​​​will vary depending on rainfall or the amount of salt in the water is one of the important determinants of the existence of any organism in that water source. Fresh water and salt water are very different. Freshwater plants or animals have more salt in their cells than in living water. These creatures will get rid of salt as waste Sea-dwelling plants and animals have an equal or lesser amount of salt than their living habitats and have a physiological mechanism to maintain the balance of salt. In addition, these organisms. Can also tolerate salinity changes in living water.