Niobium (Nb)

Atomic number: 41
Atomic weight: 92.9064
Average concentration in ocean: 3.8 pmol/kg
Residence time:  n.d.

Distribution in ocean
The niobium vertical profile has a slight depletion near the surface and a subsurface maximum indicating that it has some nutrient-like properties.  The deep portion is relatively constant (data).

Speciation
Niobium is believed to be present in the +V oxidation state as Nb(OH)50 and Nb(OH)6-.

Analysis
Niobium is determined by inductively coupled plasma mass spectrometry after preconcentration.

References