My research intention is to examine the mechanisms by which phytoplankton influence the bioavailability of aerosol iron. Recent studies reveal that the bioavailability of iron strongly influences the ocean primary productivity and carbon cycling, algal species composition, and emission of greenhouse gases (N2O, DMS, and CH4) from the ocean. Aeolian inputs, namely soil dust, are the major source of new iron to remote ocean regions. Hence, the biogeochemical cycle of iron bridges the land, the atmosphere and the ocean. The processes that determine bioavailability of aerosol iron include dissolution and precipitation of iron minerals, reduction of Fe(III) and oxidation of Fe(II), and iron complexation by organic and inorganic ligands. It is established that many of these processes are influenced or even regulated by marine microorganisms, but little is known about these biological mechanisms.
I am interested in active biological processes that allow Fe acquisition from particles, in particular organism adhesion to the particle’s surface. We are currently examining the possible role of pili, an outer membrane filamentous protein structure, in adhesion to iron particles.
To address these issues I utilize both advanced microscopic methods and “wet” chemistry procedures. I combine work on both a classic model organism, Synechocystis sp. PCC 6803, and an environmentally relevant organism, Trichodesmium sp
I am interested in active biological processes that allow Fe acquisition from particles, in particular organism adhesion to the particle’s surface. We are currently examining the possible role of pili, an outer membrane filamentous protein structure, in adhesion to iron particles.
To address these issues I utilize both advanced microscopic methods and “wet” chemistry procedures. I combine work on both a classic model organism, Synechocystis sp. PCC 6803, and an environmentally relevant organism, Trichodesmium sp
TEM micrograph of Fe limited Synechocystis cells with nano scale dust particles attached to its outer sutface
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TEM micrograph of Synechocystis
cells that are aggregated with dust particles |
TEM micrograph of Iron oxide particle attached to the cell surface of Synechocystis. The particle is in direct association with the cell and with Pili, an outer membrane filamentous protein structure.
SXRF analysis of a Trichodesmium colony that collected natural dust.