About this Research Topic
210Pb and 210Po are naturally occurring radionuclides and, as a daughter-parent pair, have been increasingly used to constrain particle dynamics and fluxes of particulate organic carbon (POC) in the ocean. The particle-reactive nature and half-life of 210Po (T1/2=138.4 d) make the 210Po-210Pb pair suitable for tracking biological pump efficiencies in the epipelagic and mesopelagic zones, and for quantifying both the POC export out of the euphotic zone and the POC remineralization in the twilight zone over a longer timescale than the 234Th-238U pair can provide. Although the GEOSECS project in the 1970s has provided baseline data on both 210Po and 210Pb in major world oceans, the application of 210Po-210Pb as a POC proxy in marine environments emerged only over the past decade. The 210Po-210Pb pair has been listed as an isotopic tracer in the ongoing GEOTRACES project.
Many factors can influence the application of 210Po-210Pb and the derived POC fluxes, such as interactions between 210Po, 210Pb and particulate organic components, pulse rainfall with low 210Po/210Pb ratio, and cross-shelf transport processes, among others. Moreover, the intermediate radionuclide 210Bi between 210Pb and 210Po has been shown to influence the 210Po-210Pb model. Although recent studies have advanced our understanding of the behavior of 210Po and 210Pb in the water column, much work remains to be done. How the 210Po/210Pb signals are differently regulated between oligotrophic and eutrophic waters and between open ocean and marginal seas, and how particle composition, atmospheric deposition, and lateral transport processes control the 210Po/210Pb and POC fluxes are important scientific topics.
This Research Topic will cover recent advances in our understanding of the biogeochemistry of 210Pb and 210Po in marine environments, the utilization of 210Pb-210Po pair for quantifying POC fluxes, and the influence of particle composition on 210Pb/210Po scavenging. Authors are invited to submit their original research articles and/or reviews. Specific topics include but are not limited to:
· Recent and new methodology for 210Pb and 210Po analysis
· Biogeochemical cycling of 210Pb and 210Po in the open ocean and marginal seas, including surface ocean, mesopelagic zone, nepheloid water, hydrothermal plume, etc.
· Use of the 210Pb/210Po disequilibrium to constrain POC export out of the euphotic zone and in the mesopelagic water
· Use of the 210Pb-210Po pair to reveal resuspension on the continental shelf, seafloor, seamount, etc.
· Influence of particle composition on the scavenging of 210Pb and 210Po, based on controlled laboratory experiments and in situ investigations
· 210Po and 210Pb in the atmosphere and their deposition
· Comparative studies of the biogeochemistry of 210Po and 210Pb between different marine environments
· Development of 210Po-210Pb models for the acquisition of crucial parameters related to particle dynamics
Keywords: 210Po, 210Pb, carbon export, biological pump, fluxes
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