Helium (He)
| Atomic number: |
2 |
| Atomic weight: |
4.0026 |
| Average concentration in ocean: |
1.9 nmol/kg |
| Residence time: |
yrs |
Distribution in ocean
Helium is an inert gas that is present in seawater at concentrations that are in
equilibrium with the atmosphere at the temperature and salinity of the sample.
The vertical profile shows
concentrations at the surface which are slightly lower than those in deep water
because gas solubility decreases as temperature increases (data).
Speciation
Helium is present as elemental He gas dissolved in water.
Analysis
Helium is determined by mass spectrometry or gas chromatography.
References