New geochemical approach to reconstruct tropical palaeo-atmospheric dynamics

Project Information

PALADYN

Grant agreement ID: 834934

DOI

10.3030/834934

Project closed

EC signature date 20 June 2019

Start date 1 December 2019

End date 31 December 2022

Funded under

• EXCELLENT SCIENCE - European Research Council (ERC)

Total cost

€ 1 475 489,22

EU contribution

€ 1 475 489,22

Coordinated by

UNIVERSITAT AUTONOMA DE BARCELONA
Spain

Periodic Reporting for period 2 - PALADYN (New geochemical approach to reconstruct tropical palaeo-atmospheric dynamics)

Reporting period: 2021-06-01 to 2022-12-31

Summary of the context and overall objectives of the project

The main goal of the project is to study the impact of global climate change on the hydrological cycle and atmospheric circulation of the tropics and subtropics. These are some of the most highly inhabited regions of the planet and currently there is a large degree of uncertainty on whether global warming will lead to significant changes in the rainfall regimes in arid and monsoonal regions. In the PALADYN project we intend to develop and apply a new methodology that will help significantly to address these issues, through the study of changes in the Hadley circulation in past periods of extreme global cold and warmth. The information will be drawn from the study of dust and pyrogenic carbon in marine sediments.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

PALADYN project aimed at developing a new methodology to study past HC dynamics through the measurement of pyrogenic carbon (PyC) in deep-sea sediments. The work performed during the 3-years period of the project has been:
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.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

The new analytical methodologies set up have achieved significant breakthroughs in the analysis of black carbon (BC) in the environment, which will be of interest to scientists that work in other research fields. We have obtained higher throughput, reproducibility and sensitivity than ever before which will allow us to analyze a wide range of samples with more confidence in the results.
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.

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