Periodic Reporting for period 2 - PALADYN (New geochemical approach to reconstruct tropical palaeo-atmospheric dynamics)
Periodo di rendicontazione: 2021-06-01 al 2022-12-31
1.- Develop and application of new analytical technologies to reliably quantify black carbon (BC) in marine samples (aerosol, dissolved organic matter and sediments). This includes novel strategies to quantify trace levels of anhydrosugars in sediments, BPCAs and n-alkanes, as well as their isotopic composition.
2.- Participation in 3 oceanic cruises to retrieve samples (aerosols, DOM and sediments) from the Tropical Atlantic ocean.
3.- Mapping of the spatial distribution of BC in Atlantic sediments.
4.- Distribution and isotopic composition of dissolved black carbon in surface and deep waters of the Tropical Atlantic Ocean.
5.- Measures of BC inputs to the Tropical Atlantic Ocean associated to aerosols.
The main results and conclusions are:
1.- There are two main sources of BC to the marine environment: pyrogenic BC and diagenetic BC. Both sources display different spatial distribution and isotopic composition. The main source of PyrC to Atlantic sediments are aerosols from savannah-related wild-fires.
2.- The distribution of PyC in Atlantic surface sediments mirrors the modern latitudinal distribution of African wild-fires.
The first map of pyrogenic carbon distribution (PyrC-BPCA) in the Tropical Atlantic has been created. The BC-BPCA isotopic composition has permitted to distinguish between authigenic BC and pyrogenic BC. This data will prove essential to quantify the contribution of continentally-derived PyrC to the organic matter accumulated in ocean sediments. This a highly valuable data to further constrain the role of the ocean-land interaction in the global biogeochemical cycle of carbon.
Evidence of a link between the sedimentary accumulation of PyC and mean trajectories of biomass burning aerosols across the Tropical Atlantic Ocean. This finding is relevant because it allows the development an innovative proxy to determine the variability of the Hadley Circulation in the past.