210Pb as a tracer of shelf-basin transport and sediment focusing in the Chukchi Sea

Activities of dissolved, particulate, and sedimentary Pb-210 were measured in the shelf-slope region of the Chukchi Sea. Samples were collected as part of the Shelf-Basin Interactions (SBI) Phase II process study (6 May-15 June, 2002) along three shelf-basin transects identified as West Hanna Shoal, East Hanna Shoal, and Barrow Canyon. Distributions of Pb-210 and suspended particulate matter indicate efficient removal of Pb-210 over the shelf by particle scavenging. Low Pb-210 activities measured throughout the halocline of the Canada Basin are attributed to shelf scavenging and subsequent advective transport into the interior basin. Additionally, Pb-210 inventories were used to construct a water-column-sediment budget of Pb-210 and determine regions of particle export and deposition on the continental shelf and slope. Sediment focusing calculated with this Pb-210 budget was observed throughout the shelf-slope region, particularly in shallow (similar to 100 m) shelf waters at Barrow Canyon. Despite elevated concentrations of suspended particulate matter in Barrow Canyon, the Pb-210 budget does not indicate that sediment transport occurred from the West and East Hanna Shoals into Barrow Canyon. (c) 2008 Elsevier Ltd. All rights reserved.