Potential imprint of Spörer and Maunder solar minima on coral skeleton carbon isotopes

T. Ourbak (1, 2) , Bruno Malaizé (1) , Thierry Corrège (1, 2)

1 EPOC - Environnements et Paléoenvironnements OCéaniques
2 PALEOTROPIQUE - Paléo-environnements tropicaux et variabilité climatique

Despite being routinely measured with d¹⁸O in corals, records of d¹³C are seldom presented in paleoceanographic studies. Numerous factors influence the biologically-mediated fractionation of carbon isotopes during skeletogenesis, resulting in a complex behaviour of this tracer. Here we present a long coral d¹³C series, dating back to 1475, and showing the potential impact of solar activity. We note a significant decrease of d¹³C during the Spörer and Maunder minima. We argue for a change in metabolical processes, from an autotrophical pattern to a more heterotrophical mode of feeding guided by change in sun irradiation. In addition, nearby volcanic eruptions might also have an impact and cause d¹³C shifts, depending on the dust load associated with the eruption. Following previous work, we advocate the systematic presentation of d¹³C vs. d¹⁸O plots in coral studies to identify whether isotopic fractionation might have been affected by change in mode of feeding.

Domaines: Interfaces continentales, environnement; Sciences de la Terre; Géophysique [physics.geo-ph]

T. Ourbak, Bruno Malaizé, Thierry Corrège. Potential imprint of Spörer and Maunder solar minima on coral skeleton carbon isotopes. Climate of the Past Discussions, 2007, 3 (5), pp.1021-1035. ⟨10.5194/cpd-3-1021-2007⟩. ⟨hal-00330735⟩