Some species tolerate only intermediate levels of salinity while broadly adapted species can acclimate to any salinity ranging from fresh water to seawater. Salinity measurements may also offer clues about estuarine areas that could become afflicted by salinity-specific diseases. In the Chesapeake and Delaware bays, for example, pathogens infecting oysters are restricted to sections that fall within certain salinity levels. Drastic changes in salinity, such as those due to drought or storms, can also greatly alter the numbers and types of animals and plants in the estuary. Another role played by saline water in an estuary involves flocculation of particles.
Flocculation is the process of particles aggregating into larger clumps.
Salinity is often an important factor when monitoring many key water quality variables. As salinity increases, the amount of oxygen that water can hold decreases. If you use a meter to measure pH, the techniques are the same whether you are testing salt or fresh water. Sampling Considerations Salinity will fluctuate with movement of the tides, due to dilution by precipitation, and mixing of the water by wind. There are also seasonal differences in salinity.