the characteristic of Water Resources is ……….. Aquatic ecosystem consists of freshwater, saltwater and brackish-water. The measure salinity by the amount of dissolved salts in the water found in the form of the Part Per Thousand Saltwater from the ocean in General should be average 35 PPT, Freshwater is less than 0.5 ppt.and Brackishwater in between 0.5 – 25 ppt. Salinity will vary depending on the concentration of each factor. Most of the water ecosystem will happen to the estuary.