210Po-210Pb distribution and carbon export in the northern Gulf of Mexico continental slope

210Po and 210Pb as Tracers of Particle Cycling and Export in the Western Arctic Ocean

“…The POC and PN fluxes estimated using POC/Po and PN/Po ratio in 1-51 um size fraction were in general found higher by up to a factor 2 compared to those estimated using the POC/ 210 Po ratio in the >51 um size fraction (Supplementary Tables 1, 2). This observation is similar to what other studies have reported and can be attributed to the fact that not all suspended particles in 1-51 µm sink fast enough to contribute to the net sinking fluxes (Buesseler et al, 2006;Tang and Stewart, 2019;Bam and Maiti, 2021). The flux estimates using POC/ 210 Po ratio on smaller size fraction particles tend to overestimate when compared with sediment traps, as a significant portion of this pool can be slow sinking particles whose contribution to net flux is reduced by remineralization in the water column.…”

“…The ratios of POC/ 210 Po, PN/ 210 Po in the water column decreased with depth following a general power law (Figures 7A,B) as previously observed by number of studies (Maiti et al, 2008;Tang and Stewart, 2019;Bam and Maiti, 2021). This is expected because of the remineralization of particulate organic matter during settling through the water column and preferential association of 210 Po with POC (R 2 = 0.65) and PN (R 2 = 0.54).…”

“…These stations were in proximity to our stations 48 and 56 and the fluxes are lower than our current estimates (8.26-21.0 dpm m −2 d −1 ). 210 Po fluxes in this region is overall lower compared to other regions of the world ocean (Murray et al, 2005;Wei et al, 2011;Anand et al, 2018;Bam and Maiti, 2021). In the future, the 210 Po and 210 Pb fluxes in the Arctic might change with changing Arctic climatic conditions such as rapid ice melting, increased ice algae growth and enhanced transport of shelf sediments but our current comparison of fluxes with data collected over two decades back (Smith et al, 2003) showed no significant differences.…”

“…The average time between sample collection and initial plating of 210 Po for dissolved and particulate samples was approximately 1.5-2 months. The final Po-Pb data was appropriately corrected for decay and ingrowth between the sampling and first plating along with other radiometric decay correction (Baskaran et al, 2013;Bam and Maiti, 2021). Data on POC, PN, PIC, bSi, and δ 13 C POC data were obtained from BCO-DMO website and details on sampling and analytical methods are reported in Lam, 2020 and(Lam, 2020) 1 .…”

Activity Levels of 210Po, 210Pb and Other Radionuclides (134Cs, 137Cs, 90Sr, 110mAg, 238U, 226Ra and 40K) in Marine Organisms From Coastal Waters Adjacent to Fuqing and Ningde Nuclear Power Plants (China) and Radiation Dose Assessment

“…Due to their unique geochemical properties, 210 Po and 210 Pb are used as a tracer pair to study the dynamic processes of aerosols in the atmosphere and estimate the residence times of aerosols (Aba et al, 2020). They are also used to study particle scavenging processes in the sea, particularly in assessing the export of particulate organic carbon (POC) fluxes from the euphotic zone (Zhang et al, 2020;Bam and Maiti, 2021), as well as specific marine food chain processes (Strady et al, 2015). Indeed, beyond the oceanographic application of 210 Po and 210 Pb, their accumulation in marine organisms and transfer to human consumers of seafood, and the resulting radiation doses to marine organisms or committed effective doses to humans are also issues of public concern.…”