228Ra, 226Ra, 224Ra and 223Ra in potential sources and sinks of land-derived material in the German Bight of the North Sea: implications for the use of radium as a tracer

Schmidt, Caroline; Hanfland, Claudia; Regnier, Pierre; Cappellen, Philippe Van; Schlüter, Michael; Knauthe, Ulrich; Stimac, Ingrid; Geibert, Walter

doi:10.1007/s00367-011-0231-5

Cited by 13 publications

(34 citation statements)

References 52 publications

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“…First, the combination of runoff from European continental rivers and discharge from the Wadden Sea make up a coastal source, which is likely to support the highest Ra activities observed in the CCW. This is reasonable given that rivers are a well‐known source of Ra, and significant Ra release from the Wadden Sea tidal channels has been observed in previous studies [ Schmidt et al ., ; Moore et al ., ]. Second, consistently high Ra activities throughout the SNS point to a sedimentary Ra source.…”

Section: Resultsmentioning

confidence: 99%

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Radium isotopes as a tracer of sediment‐water column exchange in the North Sea

Burt

Thomas

Pätsch

et al. 2014

Global Biogeochemical Cycles

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Sediment-water column exchange plays an important role in coastal biogeochemistry. We utilize short-lived radium isotopes ( 224 Ra and 223 Ra) to understand and quantify the dominant processes governing sediment-water column exchange throughout the North Sea. Our comprehensive survey, conducted in September 2011, represents the first of its kind conducted in the North Sea. We find that two main sources regulate surface Ra distributions: minor coastal input from rivers and shallow mudflats and North Sea sediments as the dominant source. Pore waters show 100-fold larger activities than the water column. North Sea sediment characteristics such as porosity and mean grain size, as well as turbulence at the sediment-water interface, are the dominant factors contributing to variability of Ra efflux. Ra inventory and mass balance approaches consistently yield high benthic Ra effluxes in the southern North Sea, driven by strong tidal and wind mixing, which in turn cause high sediment irrigation rates. These results exceed incubation-based Ra flux estimates and the majority of previously reported Ra flux estimates for other regions. Ra-based estimates of benthic alkalinity fluxes compare well to observed values, and the high rates of Ra efflux imply a potentially significant exchange of other products of sedimentary reactions, including carbon and nutrient species. Passive tracer simulations lend strong support to the Ra source attribution and imply seasonal variation in the surface water Ra distribution depending on stratification conditions.

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Section: Resultsmentioning

confidence: 99%

“…Schmidt et al . [] provided the first published Ra measurements in the German Bight of the North Sea, as well as insight and motivation toward future Ra studies. Finally, an extensive study by Moore et al .…”

Section: Introductionmentioning

confidence: 99%

Radium isotopes as a tracer of sediment‐water column exchange in the North Sea

Burt

Thomas

Pätsch

et al. 2014

Global Biogeochemical Cycles

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“…5). We include some data points from Schmidt et al (2011) The transects extended about 100 km into the North Sea (Fig. 1).…”

Section: Water Columnmentioning

confidence: 99%

“…We also infer fluxes based on 222 Rn (half life = 3.8 days) and uranium (U). Schmidt et al (2011) published a study of the four Ra isotopes in the German North Sea and adjacent coastal areas. They found high activities of 224 Ra and 223 Ra in the Weser River estuary and the tidal flats, similar to activities reported by Shaw (2003).…”

Section: Introductionmentioning

confidence: 99%

Radium-based pore water fluxes of silica, alkalinity, manganese, DOC, and uranium: A decade of studies in the German Wadden Sea

Moore

Beck

Riedel

et al. 2011

Geochimica et Cosmochimica Acta

104

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“…In studies focusing on radium isotopes, Schmidt et al (2011) and Moore et al (2011) reported radon concentrations in porewater and surface water samples from the Wadden Sea. In both studies, discrete radon samples were taken and analysed in the laboratory.…”

Section: Introductionmentioning

confidence: 98%