²⁶Al in seawater and ²⁶Al/¹⁰Be as paleo‐flux tracer

Measurements of water‐column ²⁶Al/²⁷Al ratios above 850 m depth in the Pacific yield values in the range 10⁻¹³–10⁻¹⁴, translating into ²⁶Al concentrations of 20–200 atoms kg⁻¹. The atomic ratio of ²⁶Al/¹⁰Be in surface ocean is close to 1 × 10⁻⁴, at least an order lower than the atmospheric production ratio. Surface‐ocean particulate removal of Al is about 30 times more rapid than that of Be. The results of this first set of data on ²⁶Al in seawater also suggest that the source of ²⁶Al in the sea is dominated by spallation of Ar in the atmosphere (as opposed to eolian and cosmic‐dust inputs) and that the ratio ²⁶Al/¹⁰Be in marine sediments can be potentially used to decipher past variations of oceanic particle flux, hence biologic productivity.