Biological transport of zinc-65 into the deep sea

The specific activities of zinc-65 (/sup 65/Zn:Zn) in pelagic and benthic animals collected off Oregon were correlated with depth of capture to estimate vertical biological transport rates. Results suggest that about 2 yr are required for transport of /sup 65/Zn from near-surface to abyssobenthic animals. Vertical transport appears to be slower in upper waters, suggesting recycling of zinc within biological communities, and more rapid below 500 m. The long vertical transport time for zinc contrasts with the shorter times estimated for transport of zinc and other elements by fecal pellets. This raises questions about the importance of fecal pellets as a rapid transport mechanism for biologically required materials into the deep sea.