Earth Institute Contact: Dr. David Ho
The Iron Hypothesis was built around the argument that phytoplankton production in large regions of the world's oceans is limited by iron. A large number of laboratory studies, field projects, and modeling efforts continue to make this area of research a hot topic within biological and chemical oceanography. Iron fertilization from ships does result in the enhanced biological productivity of surface waters. In contrast, enhanced ocean productivity, following the atmospheric deposition of naturally occurring iron, is not well documented.
Looking to apply new technologies that link atmospheric processes with chemical and biological oceanography, a researcher from the Woods Hole Oceangraphic Institution will deploy a buoy-mounted aerosol sampler on the Bermuda Testbed Mooring (BTM) buoy with the primary objective of producing a time-series for the concentrations of mineral dust, Fe and other geochemically important elements. Aerosol sampling will start before and end after the period of the large-scale transport of African dust to the Sargasso Sea and Bermuda, which occurs in July and August. If the instrument works as designed, the proposed study will produce the first time-series to have captured and quantified dust events at the air-sea boundary from a moored buoy. The aerosol sampler deployment will coincide with Boyle's deployment of the MITESS water sampler under the BTM buoy. This joint deployment will allow for a comparison between the temporal variations in the atmospheric deposition of mineral dust (Fe) and the surface water concentrations of Fe.
While the proposed project involves testing new technologies, it has implications for drawing longer-term connections between iron deposition, primary productivity and ecosystem dynamics. Atmospheric concentrations and deposition rates of iron, derived from buoy-mounted instruments, can also provide observational data that can be compared to model simulations of iron deposition to the ocean.
Cross Cutting Themes:
National Science Foundation