Polonium-210 and Lead-210 activities measured on 9 water bottle profiles during POLARSTERN cruise ANT-XXIV/3

• Main Authors: Friedrich, Jana, Robert, Maya, Stimac, Ingrid
• Format: Dataset
• Language: English
• Published: PANGAEA 2011
• Subjects: ANT-XXIV/3; CTD/Rosette; ultra clean; CTD-RO; CTD-UC; Date/Time of event; DEPTH; water; Drake Passage; Elevation of event; Event label; GEOTRACES; Global marine biogeochemical cycles of trace elements and their isotopes; Latitude of event; Lead-210; dissolved; standard deviation; particulate; Longitude of event; Polarstern; Polonium-210; Polonium-210/Lead-210; Polonium-210/Lead-210 activity ratio; Berichte zur Polar- und Meeresforschung; Reports on Polar and Marine Research
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.763970; https://doi.org/10.1594/PANGAEA.763970

As part of the GEOTRACES Polarstern expedition ANT XXIV/3 (ZERO and DRAKE), Polonium-210 and Lead-210 have been measured in the water column and on suspended particulate matter in February to April 2008. Our goal was to resolve the affinities of 210Po and 210Pb to transparent exopolymer particles (TEP) and particulate organic carbon (POC). Polonium-210 and Lead-210 in the ocean can be used to identify the sources and sinks of suspended matter. In seawater, Polonium-210 (210Po) and Lead-210 (210Pb) are produced by stepwise radioactive decay of Uranium-238. 210Po (138 days half life) and 210Pb (22.3 years half life) have high affinities for suspended particles. Those radionuclides are present in dissolved form and adsorbed onto particles. Following adsorption onto particle surfaces, 210Po especially is transported into the interior of cells where it bonds to proteins. In this way, 210Po also accumulates in the food chain. 210Po is therefore considered to be a good tracer for POC, and traces particle export over a timescale of months. 210Pb (22.3 years half life) adsorbs preferably onto structural components of cells, biogenic silica and lithogenic particles, and is therefore a better tracer more rapidly sinking matter. Water samples were taken with Niskin bottles. Dissolved Polonium-210 and Lead-210 activities refer to the fraction < 1µm. Particulate Polonium-210 and Lead-210 refer to the activity on particles >1µm retained on nucleopore filters. Zooplankton retained on the filters was systematically removed as this study focused on phytoplankton and exudates. The data have been submitted to Pangaea following a Polonium-Lead intercalibration exercise organized by GEOTRACES, where the AWI lab results range within the data standard deviation from 10 participating labs.