Salinity measures the amount of salt in the water. All animals need salt to survive. Even in freshwater environments such as lakes, rivers, and ponds there is a little salt. Salt is measured in parts per thousand or ppt. Most freshwater typically has between 0-5 parts per thousand. This means that for every 1000 pounds of water, 0-5 pounds of salt would be in those 1000 pounds. Ocean water typically has at least 25-35ppt. Brackish water, like our wetlands area where saltwater and freshwater mix, typically have between 12-25ppt.
These areas are extremely important in catching pollution and filtering water. Wetland animals cannot handle as much salinity as creatures in the ocean. Wetlands, such as ours, also serve as more of a nursery for fish. Life that lives in a saltwater wetlands have to be able to survive times of low and high salinity. If the salinity becomes too high or low it will result in a die-off event. Salt sinks in the water, therefore areas on the bottom are more salty than at the top of the water. To determine salinity you sample in the top, middle, or bottom of the water column. A refractometer, hydrometer, or YSI can be used to measure salinity.
