copied from S2N package
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WATER TEMPERATURE [degrees C]
SALINITY [psu]
SIGMA-T [kg/m^3]
Dissolved Oxygen Concentration [micromole/kilogram]
CHLOROPHYLL A CONCENTRATION (Wetstar) [micrograms/liter]
Raw Fluorometer [volts]
phosphate concentration [micromoles/kg]
Silicate concentration [micromoles/kg]
nitrate concentration [micromoles/kg]
Nitrite concentration [micromoles/kg]
Ammonium concentration [micromoles/kg]