Area of Interest:

Phytoplankton ecophysiology and molecular biology with an emphasis on:

• Environmental factors influencing phytoplankton distributions and abundance
• Trace metal availability controls on phytoplankton ecology and evolution
• Diatom elemental requirements and nutrient uptake kinetics
• Autoecology of the toxin-producing diatom Pseudo-nitzschia
• Comparative transcriptomics in phytoplankton and environmental genomics of the upper ocean
• Development of indicators for phytoplankton nutritional status in the past and present oceans
• Phytoplankton-bacteria interactions

Education:

1998 B.Sc in Biology (McGill University)

2005 Ph.D in Botany (University of British Columbia)

2005 - 2009 Post-doctoral Fellow in Oceanography (University of Washington)

Research & Activities:

The primary research focus is biogeochemical evolution of phytoplankton in marine environments. Biogeochemical evolution is defined as the changes in the genomes of organisms and in the chemistry of their environment, as they influence each other over time. Laboratory-based and field-based studies are combined to answer fundamental questions on factors influencing phytoplankton distributions and abundance, and to advance our understanding of how these organisms interact with their environment and influence ocean biogeochemistry. Particular interests include studying trace metals, such as iron, that are essential for the nutrition of phytoplankton and how future climate changes will influence phytoplankton growth and ecology as well as ecosystem dynamics. 

Selected Publications:

(post-2007):

Marchetti A, Schruth DM, Durkin CA, Parker MS, Kodner R, Berthiaume CT, Morales R, Allen AE, Armbrust EV. (2012) Comparative metatranscriptomics identifies molecular bases for the physiological responses of phytoplankton to varying iron availability.  Proceedings of the National Academy of Science. 109:E317-E325

Ribalet F, Marchetti A, Hubbard KA, Brown K, Durkin CA, Morales R, Robert M, Swalwell JE, Tortell PD and Armbrust EV. (2010) Unveiling a phytoplankton hotspot at a narrow boundary between coastal and oceanic waters.  Proceedings of the National Academy of Science. 107:16571-16576 

Marchetti A, Varela DE, Lance V, Johnson Z, Palmucci M, Giordano, M and Armbrust EV. (2010) Iron and silicic acid effects on phytoplankton productivity, diversity and chemical composition in the central equatorial Pacific Ocean. Limnology and Oceanography. 55: 11-29. 

Marchetti A and Cassar N. (2009) Diatom elemental and morphological changes in response to iron limitation: a brief review with paleoceanographic applications. Geobiology. 7: 419-431.

Zhang Z, Sachs JP and Marchetti A. (2009) Hydrogen isotope fractionation in freshwater and marine algae: II. Temperature and nitrogen-limited growth rate effects. Organic Geochemistry. 40: 428-439. 

Marchetti A, Parker MS, Moccia LP, Ostlund EL, Arrieta A, Ribalet, F, Murphy MEP, Maldonado MT and Armbrust EV. (2009) Ferritin is used for iron storage in bloom-forming marine pennate diatoms. Nature. 457, 467-470. 

Marchetti A, Lundholm N, Kotaki Y, Hubbard KA, Harrison PJ and Armbrust EV. (2008) Identification and assessment of domoic acid production in oceanic Pseudo-nitzschia (Bacillariophyceae) from iron-limited waters in the NE Subarctic Pacific. Journal of Phycology 44, 650-661.