210Pb as a tracer of shelf–basin transport and sediment focusing in the Chukchi Sea

Lepore, Kate; Moran, S. Bradley; Smith, J. N.

doi:10.1016/j.dsr2.2008.10.021

Cited by 34 publications

(35 citation statements)

References 37 publications

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“… Moore and Smith [1986] argued that the Cesar values were closer to North Pacific surface values from the GEOSECS program (96 dpm/m 3 at 32 μ M Si [ Chung and Craig , 1980]). Similarly high 226 Ra activities (113.8, 113.8, 109.7 dpm/m 3 ) were observed in surface waters of the deep (>1000 m) Canada Basin by Smith et al [2003] but data published for the Chukchi and Beaufort shelf areas [ Smith et al , 2003; Kadko and Muench , 2005; Lepore et al , 2009] are more variable and appear to be strongly affected by biological uptake and release in these productive shelf regions.…”

Section: Resultsmentioning

confidence: 60%

Shelf‐basin exchange times of Arctic surface waters estimated from ²²⁸Th/²²⁸Ra disequilibrium

et al. 2012

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Section: Resultsmentioning

confidence: 60%

Shelf‐basin exchange times of Arctic surface waters estimated from ²²⁸Th/²²⁸Ra disequilibrium

et al. 2012

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“…Very few studies have investigated the distribution of 210 Po and/or 210 Pb in the Arctic water column [ Moore and Smith , ; Cochran et al ., ; Smith and Ellis , ; Roberts et al ., ; Smith et al ., ; Lepore et al ., ; Chen et al ., ]. The 210 Pb and 210 Po activities presented here are comparable to the wide activity range reported by those studies, including shelf and basin areas.…”

Section: Discussionmentioning

confidence: 99%

Carbon export fluxes and export efficiency in the central Arctic during the record sea‐ice minimum in 2012: a joint ²³⁴Th/²³⁸U and ²¹⁰Po/²¹⁰Pb study

et al. 2016

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The Arctic sea‐ice extent reached a record minimum in September 2012. Sea‐ice decline increases the absorption of solar energy in the Arctic Ocean, affecting primary production and the plankton community. How this will modulate the sinking of particulate organic carbon (POC) from the ocean surface remains a key question. We use the 234Th/238U and 210Po/210Pb radionuclide pairs to estimate the magnitude of the POC export fluxes in the upper ocean of the central Arctic in summer 2012, covering time scales from weeks to months. The 234Th/238U proxy reveals that POC fluxes at the base of the euphotic zone were very low (2 ± 2 mmol C m−2 d−1) in late summer. Relationships obtained between the 234Th export fluxes and the phytoplankton community suggest that prasinophytes contributed significantly to the downward fluxes, likely via incorporation into sea‐ice algal aggregates and zooplankton‐derived material. The magnitude of the depletion of 210Po in the upper water column over the entire study area indicates that particle export fluxes were higher before July/August than later in the season. 210Po fluxes and 210Po‐derived POC fluxes correlated positively with sea‐ice concentration, showing that particle sinking was greater under heavy sea‐ice conditions than under partially ice‐covered regions. Although the POC fluxes were low, a large fraction of primary production (>30%) was exported at the base of the euphotic zone in most of the study area during summer 2012, indicating a high export efficiency of the biological pump in the central Arctic.

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“…Basins for both 210 Pb and 210 Po (Smith et al, 2003) or only for 210 Pb (Hu et al, 2014;Lepore et al, 2009). This observation was explained by particle scavenging of 210 Pb and 210 Po at the sediment-water interface over the Chukchi and Beaufort shelves, where the upper halocline is formed, and subsequent advective transport into the interior Arctic (e.g.…”

Section: Considering Surface 226mentioning

confidence: 99%

Distribution of 210Pb and 210Po in the Arctic water column during the 2007 sea-ice minimum: Particle export in the ice-covered basins

Roca‐Martí

Puigcorbé

Friedrich

et al. 2018

Deep Sea Research Part I: Oceanographic Research Papers

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210 Pb and 210 Po are naturally occurring radionuclides that are commonly used as a proxy for particle and carbon export. In this study, the distribution of the 210 Po/ 210 Pb pair was investigated in the water column of the Barents, Kara and Laptev Seas and the Nansen, Amundsen and Makarov Basins in order to understand the particle dynamics in the Arctic Ocean during the 2007 sea-ice minimum (August-September). Minimum activities of total 210 Pb and 210 Po were found in the upper and lower haloclines (approx. 60-130 m), which are partly attributed to particle scavenging over the shelves, boundary current transport and subsequent advection of the water with low 210 Pb and 210 Po activities into the central Arctic. Widespread and substantial (>50%) deficits of 210 Po with respect to 210 Pb were detected from surface waters to 200 m on the shelves, but also in the basins. This was particularly important in the Makarov Basin where, despite very low chlorophyll-a levels, estimates of annual new primary production were three times higher than in the Eurasian Basin. In the Nansen, Amundsen and Makarov Basins, estimates of annual new primary production correlated with the deficits of 210 Po in the upper 200 m of the water column, suggesting that in situ production and subsequent export of biogenic material were the mechanisms that controlled the removal of 210 Po in the central Arctic. Unlike 210 Po, 234 Th deficits measured during the same expedition were found to be very small and not significant below 25 m in the basins (Cai et al., 2010), which indicates, given the shorter half-life of 234 Th, that particle export fluxes in the central Arctic would have been higher before July-August in 2007 than later in the season.

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210Pb as a tracer of shelf–basin transport and sediment focusing in the Chukchi Sea

Cited by 34 publications

References 37 publications

Shelf‐basin exchange times of Arctic surface waters estimated from ²²⁸Th/²²⁸Ra disequilibrium

Shelf‐basin exchange times of Arctic surface waters estimated from ²²⁸Th/²²⁸Ra disequilibrium

Carbon export fluxes and export efficiency in the central Arctic during the record sea‐ice minimum in 2012: a joint ²³⁴Th/²³⁸U and ²¹⁰Po/²¹⁰Pb study

Distribution of 210Pb and 210Po in the Arctic water column during the 2007 sea-ice minimum: Particle export in the ice-covered basins

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210Pb as a tracer of shelf–basin transport and sediment focusing in the Chukchi Sea

Cited by 34 publications

References 37 publications

Shelf‐basin exchange times of Arctic surface waters estimated from 228Th/228Ra disequilibrium

Shelf‐basin exchange times of Arctic surface waters estimated from 228Th/228Ra disequilibrium

Carbon export fluxes and export efficiency in the central Arctic during the record sea‐ice minimum in 2012: a joint 234Th/238U and 210Po/210Pb study

Distribution of 210Pb and 210Po in the Arctic water column during the 2007 sea-ice minimum: Particle export in the ice-covered basins

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Shelf‐basin exchange times of Arctic surface waters estimated from ²²⁸Th/²²⁸Ra disequilibrium

Shelf‐basin exchange times of Arctic surface waters estimated from ²²⁸Th/²²⁸Ra disequilibrium

Carbon export fluxes and export efficiency in the central Arctic during the record sea‐ice minimum in 2012: a joint ²³⁴Th/²³⁸U and ²¹⁰Po/²¹⁰Pb study