The continental dust machine
Fowlers Gap Arid Zone Research Station sits in a vast, 39,000-hectare area in far western New South Wales. Operated by the University of New South Wales since 1966, this facility is positioned in one of the Southern Hemisphere's most significant dust source regions. The characteristic red dust, technically known as bulldust, is a fine, powdery silt with iron oxides, which give it its distinct color. This dust originates from the dry beds of ephemeral river systems and vast salt lakes, particularly the Lake Eyre Basin, one of the primary sources for major dust events.
The station's strategic location allows scientists to study these dust events at their source. Researchers use a variety of instruments to characterize the dust plumes. Sun photometers, part of NASA's global Aerosol Robotic Network (AERONET), measure the properties of airborne particles as they pass overhead. Other instruments like nephelometers use laser light scattering to provide real-time data on dust concentrations. This ground-based data collection is important for understanding the scale and composition of dust storms that can travel for thousands of kilometers. During major events, these plumes form coherent masses of tan-colored clouds visible from space, carrying millions of tonnes of sediment off the continent.
An iron gift to the sea
The dust that lifts from the Australian interior has a direct and substantial effect on life in the Southern Ocean. These remote waters are famously low in the micronutrient iron, which limits the growth of phytoplankton, the microscopic algae that form the base of the entire marine food web. When iron-rich dust from Australia is carried by strong westerly winds and deposited into the ocean, it acts as a fertilizer, triggering extensive phytoplankton blooms.
Recent studies estimate that this windblown dust is responsible for fueling approximately one-third of all phytoplankton growth in the Southern Ocean. This process affects the carbon cycle. Through photosynthesis, the booming phytoplankton populations draw significant amounts of carbon dioxide (CO₂) from the atmosphere. When these organisms die, they sink, sequestering that carbon in the deep ocean for long periods. By linking atmospheric models with data from a fleet of robotic ocean floats, scientists can now directly quantify the relationship between dust deposition and ocean productivity, revealing how this arid region influences the planet's climate system.