Concentration (fg/kg) of radioactive isotope Protactinium-231 (231Pa) in the Beaufort Sea at 3 stations in 2007 and at 3 stations in 2009

• Main Author: Roger Francois, University Of British Columbia
• Format: Dataset
• Language: English
• Published: Canadian Cryospheric Information Network 2011
• Subjects: Beaufort Sea; Deep water; Natural radionuclides; Ocean circulation; Water column; International Polar Year-Multi-tracer investigation of the effect of climate change on nutrient and carbon cycles in the Arctic ocean; Arctic; Arctic Ocean; Canada; canada basin; Climate change; International Polar Year
• Online Access: https://dx.doi.org/10.5443/11176; https://www.polardata.ca/pdcsearch/?doi_id=11176

The dataset consists of 231Pa concentrations (fg/kg seawater) measured in the Beaufort Sea at three stations in 2007 (Sept 22-Oct 15) and three stations in 2009 (Aug 27 - Sep 12). In 2007, 20L samples were collected and quickly filtered through an Acropak cartridge (0.45 um). The samples were then acidified to pH 2 with concentrated HCl and spiked with pre-weighed quantities of 229Th and FeCl3. Acidified samples were left to equilibrate for 12 to 24 hours and their pH adjusted to 8-9 to precipitate Fe hydroxide and scavenge 230Th and 229Th. The precipitates were let to settle over 12 to 24 hours and recovered by suction with a peristaltic pump and centrifugation into a 50 ml centrifuge tube for transport to UBC where they were measured on a Element II ICP-MS. The 2007 station locations were: KC500 (71°05'N, 134°22'W, 6 samples at 6 depths), KC2000 (71°44'N, 135°30'W, 12 samples at 12 depths), and KC2700 (72°28'N, 136°56'W, 12 samples at 12 depths). In 2009, the 20L samples were filtered, acidified and stored for subsequent analysis. The 2009 station locations were: L1 (71°06'N, 139°10'W, 12 samples at 12 depths), L2 (74°30'N, 137°00'W, 12 samples at 12 depths), and L1.1 (72°31'N, 136°48'W, 12 samples at 12 depths). : Purpose: Variations in seawater 231Pa concentration with depth provide information on the lateral transport of particle reactive elements during removal by scavenging from the water column and on deep water circulation. : Summary: Comparing 230Th measurements made in 2007 and 2009 to measurements made by others in 1995 documents changes in deep water circulation in the Arctic Ocean and the penetration of a new water mass in Canada Basin. Parallel measurements of 231Pa provide complementary information regarding the source of deep water which moved into Canada Basin in 2007.