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Biogeosciences Discuss., 3, 1453-1471, 2006
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Mn seasonal upwellings recorded in Lake Tanganyika mussels

D. Langlet, L. Y. Alleman, P.-D. Plisnier, H. Hughes, and L. André
Section de Pétrographie-Minéralogie-Géochimie, Musée Royal de l’Afrique Centrale, Leuvensesteenweg 13, 3080 Tervuren, Belgium

Abstract. Biogenic productivity of Lake Tanganyika is highly dependent on seasonal upwellings of anoxic deep waters. We investigated the shell of freshwater bivalve Pleiodon spekii as a geochemical archive of these periodic hydrological changes tuned by the monsoon regime. The results of a 2-years-long geochemical survey of the coastal waters performed on the dissolved and particulate fractions were put in perspective against laser ablation ICP-MS profiles of Mn in five aragonitic shells from the same lake location. Skeletal Mn profiles in 3 shells are very similar and dominated by episodic peaks that matched the Mn increase recorded in surface waters during the 2002 upwelling, while a shell collected during 2003 dry season detect both 2002 and 2003 upwelling events. Larger shells showing an extremely reduced growth display more than 8Mn peaks suggesting at least an 8 years record of seasonal changes in water composition.

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Citation: Langlet, D., Alleman, L. Y., Plisnier, P.-D., Hughes, H., and André, L.: Mn seasonal upwellings recorded in Lake Tanganyika mussels, Biogeosciences Discuss., 3, 1453-1471, 2006.   Bibtex   EndNote   Reference Manager