Marine sediments represent the main reservoir for black carbon (BC) residues in the ocean, playing an essential role in the global carbon cycle. Therefore, sediments constitute an important environmental compartment for determining the distribution and emission sources of BC. The BC term encompasses a wide range of combustion continuum generated during the incomplete combustion of organic matter. The quantification of the polycondensed aromatic fraction of BC can be performed by oxidizing BC to generate benzene polycarboxylic acids (BPCAs). These compounds have been widely applied as specific markers to quantify and characterize pyrogenic carbon (PyC) in environmental matrices. In order to improve our understanding of the global carbon cycle is essential to disentangle the sources, fate and composition of the organic carbon accumulated in marine sediments. Our results show a preferential accumulation of BPCAs in sediments in a latitudinal band, which indicates an association with PyC emissions from Savannah wildfires. The isotopic signature for B6CA and B5CA indicates C4-type plants as the main source of PyC. In contrast, the isotopic signature of continentally-derived n-alkanes is consistent with C3-type plants. Therefore, the isotopic data indicates that there are two different sources of continentally-derived organic carbon. The PyC source is quantitatively dominant and is related to the burning of African savannah ecosystems. A second source of continentally derived organic matter is quantitatively less important and corresponds to C3-type plants of unknown origin.

Primary Presenter: Nuria Penalva Arias, Autonomous University of Barcelona (UAB) (Nuria.Penalva@uab.cat)

Authors:

Nuria Penalva-Arias, Institute of Environmental Science and Technology (ICTA-UAB)  (Nuria.Penalva@uab.cat)

Nina Davtian, Institute of Environmental Science and Technology (ICTA-UAB)  (Nina.Davtian@uab.cat)

Oriol Teruel, Institute of Environmental Science and Technology (ICTA-UAB)  (Oriol.Teruel@uab.cat)

Pau Comes, Institute of Environmental Science and Technology (ICTA-UAB)  (Pau.Comes@uab.cat)

Nuria Moraleda-Cibrián, Institute of Environmental Science and Technology (ICTA-UAB)  (Nuria.Moraleda@uab.cat)

Maria Raja, School of Chemistry, University of Nottingham  (maria.raja.sanchez@gmail.com)

Antoni Rosell-Melé, Institute of Environmental Science and Technology (ICTA-UAB) and Institució Catalana de Recerca i Estudis Avançats (ICREA)  ()

Joan Villanueva, Institute of Environmental Science and Technology (ICTA-UAB)  (Juan.Villanueva@uab.cat)