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| Legeleux, F; Reyss, Jl; Bonte, P; Organo, C. |
| Elemental analyses were carried out by Neutron Activation Analysis on eleven sediment cores from the North-East Tropical Atlantic, collected at two sites of the French EUMELI programme. Total uranium, molybdenum and arsenic concentrations increase from the surface to about 20 cm depth in cores from the eutrophic site, but remain constant in cores from the mesotrophic site. These profiles clearly highlight an enrichment of the three elements in the sediments from the eutrophic site, linked to the suboxic conditions encountered in these sediments. This entrapping of uranium in suboxic sediments, observed in previous studies (Barnes and Cochran, 1990; Klinkhammer and Palmer, 1991), is thus confirmed at the EUMELI eutrophic site. Furthermore, other elements,... |
| Tipo: Text |
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| Ano: 1994 |
URL: http://archimer.ifremer.fr/doc/00099/21005/18631.pdf |
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| Schmidt, S; Nival, P; Reyss, Jl; Baker, M; Buatmenard, P. |
| Dissolved and particulate Th-234 activities were determined and phyto- and zooplankton biomass were periodically measured 8 miles off Nice (Mediterranean Sea) during spring 1987. The results show a strong variability of Th-234 distribution on short time scales in northwestern Mediterranean surface waters. The good correlation observed between the zooplankton biomass and the rate of Th-234 export to deep water in particulate form is in agreement with the assumption that the residence time of particulate Th-234 in oceanic surface waters is controlled by zooplankton grazing. Moreover, our results indicate the importance of salps in particular as efficient removers of small suspended particles in surface waters. |
| Tipo: Text |
Palavras-chave: TH-234; ZOOPLANKTON; SCAVENGING; PARTICLE FLUX. |
| Ano: 1992 |
URL: http://archimer.ifremer.fr/doc/00100/21155/18774.pdf |
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