DustTraffic: Transatlantic fluxes of Saharan dust: changing climate through fertilising the ocean?

Within the DustTraffic project we are studying the transatlantic fluxes of Saharan dust and its environmental effect on the Atlantic Ocean.

Warming or cooling the atmosphere?

Each year, massive amounts of Saharan dust are blown from the coast of northern Africa across the Atlantic Ocean towards the Americas. On its journey, the dust has direct and indirect influences on the climate, leading to cooling or warming the atmosphere. Dust blocks incoming solar radiation in the high atmosphere but also traps outgoing heat from the earth’s surface. In addition, the dust transports microbes and spores that can harm marine and terrestrial life, but also carries nutrients and metals that can boost marine life. Consumption of these nutrients during photosynthesis in the photic zone converts the inorganic greenhouse gas CO₂ into organic matter which is eventually exported to the deep ocean.

Trapping dust

To determine the temporal and spatial variability of Saharan dust transport and deposition and their environmental effects across the equatorial North Atlantic Ocean, we have set up a monitoring experiment using deep-ocean sediment traps as well as surface buoys below the Saharan dust plume from north-west Africa to the Caribbean along the 12^th parallel.

Sampling Saharan dust in the air as well as under water over three years at a biweekly resolution allows us to:

1)      Quantify the seasonal variability of Saharan dust transport and export into the Atlantic

2)      Determine the dust’s impact on the phytoplankton in terms of potential fertilization and transportation of biomass to the deep ocean