Ruthenium-106 in the Black Sea

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摘要：

Profiles of Chernobyl 106 Ru and 137 Cs were obtained at margin and interiorsites in the Black Sea between 1986 and 1988. The data show a vertical separation in the activity distributions of these two tracers. Ruthenium-106 is found at depths below the Chernobyl 137 Cs, indicating that 106 Ru is removed via particle scavenging processes, unlike the Cs isotopes which serve primarily as tracers of physical mixing. In 1988, more detailed measurements at depths near the oxic/anoxic interface suggest that a subsurface maximum in 106 Ru occurs at the same depth as the particulate Mn maximum above oxygen zero, with perhaps a secondary peak below. Inventory calculations indicate that while 106 Ru has been significantly scavenged from the upper 50m, the net loss of 106 Ru from the upper 200m has been relatively small since its input in 1986. This implies that substantial 106 Ru is remineralized from sinking particles, and returns to the dissolved pool, thus limiting net export and increasing the apparent residence time of Ru. Relatively high deep water 106 Ru inventories (50% of total) suggest that a substantial fraction of the 106 Ru transient tracer reaches the deep waters as a pulse shortly after delivery. This is analogous to what has been seen for the weapons testing fallout radionuclide, 239,240 Pu.

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Black sea Fallout Deep water Depth Isotopes Mixing Oceans Oxygen Particulates Profiles Pulses Sinking Sites Subsurface Weapons Radioactive isotopes Reprints