Temporal Variability of Pb, Fe, and Al in the Subtropical North Atlantic and North Pacific Oceans

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Studies of biogeochemical processes in the upper ocean are often hampered by the large temporal variations in elemental concentrations and our limited ability to collect samples on relatively infrequent sampling cruises. This is particularly important for trace elements which have both a highly variable eolian source and are involved in biological processes in the euphotic zone. The PI, Boyle, proposes to examine the issue of the temporal variability of Pb, Fe and Al using a novel moored in-situ trace element sampler (MITESS) to collect high frequency trace metal samples. Pb has an anthropogenic source that is decreasing, and this long term trend is of interest to the PI and the environmental sciences community. Fe is thought to be an essential micronutrient and the Fe cycle is currently of great interest to scientists involved in understanding present and past ocean productivity and the role of the oceans in the global carbon cycling. Al is being studied to support the Pb and Fe work, as it acts as a tracer of natural eolian sources (i.e. dust) and scavenging processes. Sampling would take place in conjunction with ongoing mooring and biogeochemisty programs at the Bermuda Atlantic Time-Series Site (BATS), and the Hawaii Ocean Time-Series Site (HOTS). As such, the results of this trace metal study can be interpreted within the context of concurrent biogeochemical rate measurements and physical and optical studies, as well in conjunction with time-series atmospheric sampling at Bermuda. It can be expected that the collection of these unique sample sets and their interpretation within the context of ongoing programs will lead to many advances in our understanding of trace metal cycling, bioavailability, the effects of metals on organism growth, and the fate of anthropogenic trace metals in the oceans.