Polonium-210 and lead-210 in the marine environment

Shannon, L. V.; Cherry, Robert; Orren, M. J.

doi:10.1016/0016-7037(70)90072-4

Cited by 155 publications

(66 citation statements)

References 20 publications

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“…Most of the 210 Pb that is bound to the cell walls is excreted with the feces. This is consistent with data reported by Shannon et al (1970), Kharkar et al (1976), Beasley et al (1978) and Heyraud and Cherry (1979), which indicated high 210 Po/ 210 Pb ratios in various plankton species. Fisher et al (1983) concluded that 210 Po/ 210 Pb ratios in fecal pellets of zooplankton are half those of their phytoplankton food supply in field samples.…”

Section: Affinity Of 210 Po and 210 Pb For Poc And Biogenic Silicasupporting

confidence: 92%

A two-tracer (210Po–234Th) approach to distinguish organic carbon and biogenic silica export flux in the Antarctic Circumpolar Current

Friedrich

Loeff

2002

Deep Sea Research Part I: Oceanographic Research Papers

111

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We attempt to quantify and qualify the particle export from the surface water of the Antarctic Circumpolar Current during a spring phytoplankton bloom by the simultaneous use of the tracers 210 Po and 234 Th. We present data from the Southern Ocean JGOFS expedition in 1992 at about 61W, from the marginal ice zone to the Polar Frontal region. Radionuclide export was calculated with a one-dimensional non-steady-state scavenging model. Rapidly changing activities of 210 Pb and 210 Po during the phytoplankton bloom and the application of the tracer pair 210 Po/ 210 Pb with particle-reactive parent and daughter required a new solution to the non-steady-state scavenging model. The observed fractionation of 210 Po and 234 Th on particles, dependent on particle composition (POC/biogenic silica ratio), corroborates the known preference of 210 Po for cytoplasm. A combination of these two tracers can help to characterize the nature (i.e. organic carbon and biogenic silica content) of the material settling out of the mixed layer, and thus to arrive at a more detailed interpretation of export fluxes than is possible with 234 Th alone. In the Polar Front region, where diatoms are dominant in the phytoplankton and where the highest export rates were observed, we find a preferential settling of biogenic silica when heavily silicified diatom species occur. In contrast, POC and biogenic silica are exported with comparable efficiency when diatom species with thinner frustules prevail. The export of biogenic opal and carbon is then closely coupled. In the southern Antarctic Circumpolar Current (sACC), where siliceous organisms are not dominant in the plankton, we find a preferential settling of siliceous material over POC. r

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Section: Affinity Of 210 Po and 210 Pb For Poc And Biogenic Silicasupporting

confidence: 92%

A two-tracer (210Po–234Th) approach to distinguish organic carbon and biogenic silica export flux in the Antarctic Circumpolar Current

Friedrich

Loeff

2002

Deep Sea Research Part I: Oceanographic Research Papers

111

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“…The extremely short residence time of Th or Po has been reported by many authors (e.g. BHAT et al, 1969;SHANNON et al, 1970;Tsu NOGAI, 1973, 1976;TUREKIAN et al, 1974;BACON et al, 1976).…”

Section: Difficulties In the Scavenging Model 1)mentioning

confidence: 74%

Settling model for the removal of insoluble chemical elements in seawater.

Tsunogai

Minagawa

1978

Geochem. J.

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"Settling model" is proposed as a removal mechanism of chemical elements in the ocean on the basis of the behavior of insoluble radionuclides in seawater. In the settling model more than 20 elements such as Fe and Th exist substantially in one particulate phase which is settling with a mean velocity of 2 X 10-4 cm/sec by forming large particles with organic material. There is much favorable evidence for the settling model such as the coincidence of the residence time of these insoluble elements, specific activity of settling material similar to that of particles suspended in seawater, nearly the same proportion, about 10%, of particulate fraction (> 0.45µm) for all the insoluble elements when subsurface water is filtered, etc. The settling model is applied to Th-234 in the surface water and the vertical eddy dif fusivity of the water is calculated to be about 30cm2/sec.

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“…Particulate 210 Po activity has a negative correlation to chlorophyll a and TSM, suggesting the dilution effect 210 Po activity in bulk plankton ranged from 4.32 to 11.5 dpm/g dry weight (Table 3), which is comparable to values in zooplankton of the Caribbean Sea (31-114 dpm/ g dry weight, Kharkar et al, 1976) and to those in zooplankton of the Atlantic Ocean (1.6-196 dpm/g dry weight, Turekian et al, 1974). Shannon et al (1970) demonstrated that 210 Po activity in zooplankton was four-fold higher than that in phytoplankton and 210 Po activity in higher organisms is greatly enriched. Because the organism that made up red tide was predominantly phytoplankton in this study, 210 Po activity for bulk phytoplankton might be relatively much lower than in data published elsewhere.…”

Section: Distributions Ofmentioning

confidence: 99%

“…234 Th and 210 Po are well known for being particle-reactive chemical property, although they may not follow the same geochemical pathway. 210 Po is more reactive with biogenic particles than other nuclides (Shannon et al, 1970;Kharkar et al, 1976;Beasley et al, 1978;Tanaka et al, 1983;Turekian et al, 1974). Shannon et al (1970) determined that the enrichment factors of 210 Po from seawater, phytoplankton and zooplankton were 1, 6 and 23, respectively.…”

Section: Introductionmentioning

confidence: 99%

Scavenging of 234Th and 210Po in surface water of Jinhae Bay, Korea during a red tide

Kim

Yang

2004

Geochem. J.

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This observation was carried out on the surface seawater of Jinhae Bay, southeastern Korea during a red tide in July, 1991 in order to understand the removal processes of reactive trace elements using natural radionuclides of 234 Since the 1970s, Jinhae Bay has been investigated by many researchers and the NFRDI (National Fisheries Research and Development Institute) for chemical and physical characteristics in seawater and sediment and for the occurrence and magnitude of algal blooming throughout the year, except for winter (Park, 1975a, b;Lee et al., 1981;Yang and Hong, 1982;Yang et al., 1984;Yang and Hong, 1988;Hong et al., 1991;Lee et al., 1993). Lee et al. (1993) reported that the formation of a sub-oxic or an anoxic environment in the bottom waters of Jinhae Bay resulted in a remarkable exhaustion of dissolved oxygen by the degradation of organic matter accumulated on surface sediments, as well as by the stratification of the water mass. Spatial and temporal variations of low oxic water mass strongly depend on the stratification, which is affected by meteorological and maritime conditions. Although many studies have been conducted in Jinhae Bay, the residence time and the fate of reactive trace metals in seawater have not yet been studied. Under a red tide environment, there have been few investigations of the scavenging processes of reactive trace metals with tracers of short-lived 234 Th and 210 Po in the coastal surface area. The objectives of this study, therefore, are to understand the removal processes of reactive trace elements using co-tracers of 234 Th and 210 Po during algal blooming, and to estimate the residence time of 234 Th in the surface seawater of Jinhae Bay.

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Polonium-210 and lead-210 in the marine environment

Cited by 155 publications

References 20 publications

A two-tracer (210Po–234Th) approach to distinguish organic carbon and biogenic silica export flux in the Antarctic Circumpolar Current

A two-tracer (210Po–234Th) approach to distinguish organic carbon and biogenic silica export flux in the Antarctic Circumpolar Current

Settling model for the removal of insoluble chemical elements in seawater.

Scavenging of 234Th and 210Po in surface water of Jinhae Bay, Korea during a red tide

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