Convert between different salinity measurements commonly used in Great Salt Lake.
Salinity varies wildly in Great Salt Lake depending on location, season, and other factors. It is an important factor in Great Salt Lake's ecosystem and industrial activities. Salinity is any measure of the amount of salt dissolved in water. There are many different ways this is done, ranging from inexpensive and simple field measurements to laboratory analyses with specialized instrumentation. Values produced using different methods are not interchangeable, making it difficult to compare studies that utilize different salinity measurement methods. Empirical relationships between the different measurement types have been published for Great Salt Lake, which are the basis for this conversion tool.
Measures the mass of dissolved salts per unit volume of water. It is derived electronically by passing an electric current between electrodes on a CTD probe or conductivity meter. Higher ion concentration allows higher current flow, which is then converted to mass concentration using temperature-corrected algorithms.
Measures the mass per unit volume of the overall water solution. In the field or laboratory, density is commonly measured directly using a glass hydrometer, an oscillating U-tube density meter, or pycnometry. For high-precision measurements of salinity, the Great Salt Lake Salinity Advisory Committee (2020) recommends the use of an oscillating U-tube meter and provided a Standard Operating Procedure.
Measures how light bends (refracts) as it passes through a drop of water on an optical or digital handheld refractometer. Dissolved salts bend light proportionally to their concentration, allowing quick field estimates calibrated to standard NaCl solutions. Refractometers are inexpensive and simple to use in the field, and refractometer-based measurements correlate closely with density under a wide range of conditions in GSL (Frantz et al., 2023). Where salinity measurement precision < 1% is not needed, refractometer-based measurements may be sufficient.
Represents the mass fraction of dissolved salt relative to the total mass of the water sample (grams of salt per 100 grams of solution). This metric is typically determined by gravimetric analysis—weighing a water sample, evaporating off pure water in an oven, and weighing the remaining salt crystals. It is infrequently used in Great Salt Lake studies.
Naftz, et al. (2011) An Equation of State for Hypersaline Water in Great Salt Lake, Utah, USA. doi:10.1007/s10498-011-9138-z. | Equation of State used for temperature-dependent density - conductivity conversions for waters of GSL.
Great Salt Lake Salinity Advisory Committee (2020). Standard Operating Procedure--Great Salt Lake Water Density Measurement and Salinity Calculation. UGS Open-File Report 728. | Recommended procedure using a density meter for high-precision salinity measurements in GSL.
Mcilwain, H.E. (2023). Density and salinity data to validate an equation of state for hypersaline water in Great Salt Lake, Utah, 2021–2022. doi:10.5066/P96MNH8J. | Extended the validity of the Naftz (2011) Equation of State to 270 g/L.
Frantz et al. (2023) Desiccation of ecosystem-critical microbialites in the shrinking Great Salt Lake, Utah (USA): Supplemental Materials. doi:10.1371/journal.pwat.0000100. | Empirical relationship between refractometer % measurements and density for surface waters of GSL.