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210Po, 210Pb, and poc in the mesopelagic: multi-technique water column sampling in medflux
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tarix | 05.03.2018 | ölçüsü | 528 b. | | #29731 |
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210Po, 210Pb, and POC in the mesopelagic: multi-technique water column sampling in MEDFLUX G. Stewart P. Masque, J.K. Cochran, J.C. Miquel, B. Gasser, D. Hirschberg, A. Rodriguez y Baena, and S. Fowler
Review of 210Po and 210Pb behavior Review of 210Po and 210Pb behavior 210Po and POC relationship What happens in the Mesopelagic? - Sediment traps indicate loss of 210Po and POC
- Water column POC decreases (Pumps)
- No evidence of water column 210Po decrease
- Pumps vs. Bottles
Possible explanations and conclusions
Ubiquitous Trace Natural Radionuclides Both Highly Particle-Reactive 210Po Specific Affinity for Organic Matter, Protein - Predictable uptake by planktonic particles
- Elevated concentrations in higher trophic levels
- Highest dose of radiation to organisms
Relationship between 210Po and 210Pb May Provide Additional Information Beyond 234Th
210Pb, 210Po and Carbon Cycles
210Po, 210Pb profiles in both pumps and bottles 210Po, 210Pb profiles in both pumps and bottles Sediment traps at 2 depths during 2 periods (Spring: 200m, 800m and Summer: 200m, 1940m)
Disconnect: POC and Particulate 210Po or Pumps and Bottles?
Swimmers Have High Po/Pb
Bottles vs. Pumps Bottles capture high 210Po swimmers at depth March through May Po/Pb differs June profiles are similar Neither pump nor bottle Po/Pb reflects evidence of POC remineralization
Mesopelagic Story No evidence of Polonium remineralization: WHY? - Long radioactive half-life?
- Sorption with depth?
- Mediterranean water bodies?
- Rapid sinking?
Need to investigate further Po/Pb as POC tracer below the euphotic zone
Acknowledgements Funding for research from NSF to MEDFLUX, AAUW to GMS Captain and Crew of R.V.Tethys (Monaco) and R. V. Seward Johnson (Harbor Branch) All the participants in MEDFLUX
Review of Surface Sediment Trap Material
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