New strategy to evaluate trace element fluxes to the ocean from aerosols

HsiehScientists participating in GEOTRACES have developed a new strategy to evaluate trace element fluxes to the ocean from aerosols (Hsieh et al, 2011). The new approach uses the common geochemical behaviour of two isotopes of the same chemical element (thorium;Th), whose sources to the surface seawater are totally different (and independent). 230Th is a decay product of the homogeneously distributed 234U in seawater and provides a measure of the residence time of Th element in surface waters. This residence time is applied to 232Th content of the same water column. Because 232Th derives from dust from weathered rocks and enters the ocean surface waters in aerosols, knowing its amount and residence time allows reconstruction of the input of aerosol to the ocean surface. Hsieh and co-workers successfully applied this approach in the central Atlantic Ocean, including an assessment of aerosol fluxes associated with the dust plume blowing from South American over the South Atlantic (see photo).

This new method is now being incorporated into GEOTRACES cruises across the Atlantic and beyond.

Reference:

Yu-Te Hsieh, Gideon M. Henderson, Alexander L. Thomas (2011), Combining seawater 232Th and 230Th concentrations to determine dust fluxes to the surface ocean Earth and Planetary Science Letters, 312 (3-4) DOI: 10.1016/j.epsl.2011.10.022

Latest highlights

Elevated methylmercury level in Arctic rain and aerosol linked to oceanic dimethylmercury emissions

He and colleagues highlight a previously underappreciated pathway of mercury transport, underscoring its significance to human health.

Unveiling the Complexity of Lead Distribution in the Pacific Ocean: Insights from the GEOTRACES GP15 Transect

This recent study by Jiang and colleagues investigate the distribution and sources of lead in the Pacific Ocean.

Organic matter export rates along a North-South Pacific Ocean section: what three estimating methods tell us

Quay and his colleagues present estimates of the organic matter export rate along the GEOTRACES GP15 cruise section.

East-West contrasting fate and anthropogenic inputs for dissolved trace metals in the Subarctic Pacific Ocean

Chan and co-authors report the full-depth distribution of dissolved nickel, copper, zinc, and cadmium in the North Pacific Ocean.

Rechercher