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Anthropogenic CO2 in the Dakar (Senegal) Urban Area Deduced from 14C Concentration in Tree Leaves

Published online by Cambridge University Press:  14 June 2017

Maurice Ndeye*
Affiliation:
Laboratoire Carbone 14, Institut Fondamental d’Afrique Noire (IFAN), Université Cheikh Anta Diop de Dakar, Dakar, Senegal
Matar Sène
Affiliation:
Faculté des Sciences et Techniques, Université Cheikh Anta Diop de Dakar, Dakar, Senegal
Doudou Diop
Affiliation:
Laboratoire de Botanique, Institut Fondamental d’Afrique Noire (IFAN), Université Cheikh Anta Diop de Dakar, Dakar, Senegal
Jean-François Saliège
Affiliation:
Laboratoire d’Océanogrphie (LOCEAN), Université Pierre et Marie Curie, Paris VI, France (deceased 1 June 2012)
*
*Corresponding author. Email: maurice.ndeye@ucad.edu.sn.

Abstract

Radiocarbon (14C) in atmospheric CO2 for the Dakar (Senegal) urban area was measured using tree leaves collected by botanists from 1900 to 2003. The aim of our study was to compare the local Suess effect in Dakar to the global one during the 20th century. The ∆14C of atmospheric CO2 in this region decreased from 1900 to 1958 during the pre-bomb era (–2±5‰ to –22±4‰). From 1958 to 1964, nuclear bomb tests injected a large amount of artificial 14C into the atmosphere, reflected in the rise of ∆14C values. In the Dakar region, the atmospheric ∆14C reached 773±8‰ in 1964, but subsequently decreased to 80±5‰ by 2003, which is consistent with the global exponential decreasing trend. The ∆14C record presented here remains slightly lower than the global record. This result is attributed to the input of anthropogenic fossil carbon into the atmosphere. The amount of carbon input can be evaluated by comparing urban areas to those of clean air sites. The calculation of anthropogenic fossil carbon is deduced from a simple mathematical model.

Type
Studies of Calibration, Environment, and Soils
Copyright
© 2017 by the Arizona Board of Regents on behalf of the University of Arizona 

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Footnotes

Selected Papers from the 2015 Radiocarbon Conference, Dakar, Senegal, 16–20 November 2015

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