| Atomic number: | 12 |
| Atomic weight: | 24.305 |
| Average concentration in ocean: | 52.7 mmol/kg |
| Residence time: | 13,000,000 years |
Distribution in ocean
Magnesium is the third most abundant element dissolved in seawater (on a molar
basis). It has a generally conservative distribution
that varies only due to differences in evaporation or precipitation in the water
that sank to form intermediate or deep waters in the sea (data).
Concentrations are higher in the Atlantic because that ocean is saltier.
Recent work ,using high precision analyses with isotope dilution mass
spectrometry, suggests that there is a magnesium minimum near 2500 m depth that
is produced by consumption in hydrothermal systems (de Villiers and Nelson,
1999).
Speciation
Magnesium is present in seawater as the Mg2+ ion.
Residence time
The magnesium residence time is from Tracers in the Sea (Broecker, W. S. and
Peng, T.-H., 1982. Eldigo Press, Palisades, NY). It was calculated
from the global average river input.
Analysis
References