Importance of Saharan dust and climate change effects under study

ICREA researcher Antoni Rosell, from ICTA-UAB, participates in an international research which analyses the processes of transport and deposition of Saharan dust and African fires. Environmental dust contributes to the cooling of the planet and fertilises oceans.

06/05/2016

Studying the processes of transport and deposition of dust from the Saharan desert and African fires to determine its importance in regulating the planet's climate and marine ecosystems. These are the main objectives of the scientific expedition JC134 of the Royal Research Ship James Cook, organised by the NIOZ Royal Netherlands Institute for Sea Research and in which ICREA researcher Antoni Rosell, from ICTA-UAB, participated. This is the last transatlantic cruise conducted under the framework of the Dust Traffic project led by Jan Berend Stuut and funded by the European Research Council (ERC).

The project aims to quantify transatlantic dust and soot flows from Africa and their influence on climate change processes such as ocean fertilisation and change in the energetic balance of the atmosphere.

To do so, researchers gathered samples of desert dust along the ocean from close to Venezuela in the Caribbean to Cape Verde and the Canary Islands. This is a good moment in the year to conduct the research given that the winds are blowing from the African continent towards South America, the Sahara is the dustiest desert in the planet and Central Africa is where the majority of fires originate.

For four weeks, the scientific expedition gathered samples of mineral desert dust and soot suspended in the air above the Atlantic Ocean heading towards South America by using dust collectors and buoys.

"We want to analyse the process of transport and redistribution of these materials all over the planet and particularly from the African continent to the ocean and even to other continents", explains lecturer and ICTA-UAB researcher Antoni Rosell, who highlighted the importance of dust in the regulation of the planet's climate. Atmospheric dust contributes to the cooling of the planet by acting as a screen when suspended in air, therefore reflecting solar light back into space. Rosell adds that "when deposited in oceans, the nutrients it carries allows fertilising the ocean and contributes to a greater productivity of algae, which absorbs the CO2 found in the atmosphere".

Scientists consider it necessary to perform in-depth studies of the functions of this mineral dust and the effects of its moving around the planet. "We need to learn about the composition of the particles, how they are transported and the effects it can have on the areas in which it is deposited", Rosell states.

The scientists analyse the size of the particles, the composition of each one of them and their degree of mobility according to their composition. They will also study how the dust from Central African fires is transported and analyse its organic composition.

The final objective is to understand current processes in order to reconstruct past climate changes and thus be able to predict future processes and tendencies.