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| Lambert, Ce; Nicolas, E; Veron, A; Buatmenard, P; Klinkhammer, G; Lecorre, P; Morin, P. |
| We have investigated total Pb distributions in the water column from various sites in the north-east Atlantic. Sea water samples were collected during the Fluxatlante cruise in 1985. Total Pb ranged from 35 to 45 ng.l-1 (170-220 pmol l-1) in surface waters and decreased with depth in a manner consistent with previous findings. The high concentrations in surface waters probably reflect an important anthropogenic input of Pb from the atmosphere. Concentrations of total Pb are higher than in the western Atlantic. This difference seems to be closely related to the difference in atmospheric inputs of anthropogenic Pb. Three of the stations exhibit a specific Pb excess at the depth of the Mediterranean waters outflowing in the intermediate Atlantic waters; such... |
| Tipo: Text |
Palavras-chave: TOTAL PB; NORTH ATLANTIC; MEDDY; POLLUTION. |
| Ano: 1991 |
URL: http://archimer.ifremer.fr/doc/00102/21279/18888.pdf |
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| Corn, M; Belviso, S; Nival, P; Vigot, A; Buatmenard, P. |
| We report results from free-drifting sediment trap deployments at 200 m depth which enable measurement of the diel variations in the downward flux of detrital particulate dimethylsulphoniopropionate (DMSPp) over periods of 24-72 hours in three contrasting trophic regimes of the tropical northeastern Atlantic Ocean off Mauritania. The source of DMSPp was the phytoplankton living in surficial water layers. The three regimes exhibited similar strong diel cycles, the nocturnal fluxes being up to 100-fold lower than the daytime fluxes. High (or low) detrital DMSPp, fluxes were associated with high (or low) numbers of pteropods trapped inside the sampling cups. Thus, contamination of sinking material is likely to have occurred, promoting an overestimate of the... |
| Tipo: Text |
Palavras-chave: SULFUR; DMS; DMSP; ZOOPLANKTON; SEDIMENTATION. |
| Ano: 1994 |
URL: http://archimer.ifremer.fr/doc/00098/20886/18500.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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| Lambert, Ce; Veron, A; Buatmenard, P; Heyraud, M; Grousset, F; Simpson, W. |
| Pb concentrations were measured on large particles (diameter > 10-mu-m) at seven stations in North East Atlantic waters, and Pb isotopic composition was determined on one sediment core (Fluxatlante cruise, 1985). In intermediate and deep waters, Pb concentrations on large particles are about 0.5 ng l-1, less than 1 % of total lead and show a close correlation with Pb-210. This suggests that lead is primarily scavenged from the dissolved Pb pool in surface waters with little further scavenging in deep waters. Such an interpretation is supported by our observation of stable Pb isotopic ratios in surficial sediments which suggests that a rapid coupling exists between the atmospheric input of Pb to surface waters and its delivery to the water-sediment... |
| Tipo: Text |
Palavras-chave: PB; MARINE POLLUTION; NORTH ATLANTIC; BIOGENIC CYCLING. |
| Ano: 1991 |
URL: http://archimer.ifremer.fr/doc/00102/21280/18889.pdf |
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