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Alyson Santoro Marine microbiologist

The Santoro laboratory studies marine microbes involved in nutrient cycling, especially of the element nitrogen. Nitrogen is the limiting nutrient for primary production and carbon fixation throughout most of ocean, so understanding its sources and sinks are essential to understanding nutrient flow in the sea. Her research group uses a combination of laboratory and field studies to understand the ecology of marine microbes and their contribution to global elemental cycles using a combination of molecular biology, cultivation, and stable isotope geochemistry.

Marine archaea are a specific focus of Santoro’s research. Archaea are single-celled organisms, distinct from bacteria, which form their own domain of life. They were once thought to be confined to ‘extreme’ environments of high pressure, temperature, or salt content but it is now known that archaea also inhabit more moderate environments such as the ocean and soils. Recent work in the lab has brought several marine archaea into culture, and shown their importance in producing the greenhouse gas nitrous oxide (N2O).


Simons Foundation Early Career Investigator in Marine Microbiology, 2015.

Sloan Research Fellowship, 2015.

Relevant Publications

W.D. Orsi et al, "Ecophysiology of uncultivated marine euryarchaea is linked to particulate organic matter," ISME J., vol. 9, no. 8, pp. 1747-63, Aug. 2015.

A.E. Santoro et al, "Genome and proteome of ‘Candidatus Nitrosopelagicus brevis’: An ammonia-oxidizing archaeon from the open ocean," Proceedings of the National Academy of Sciences, vol. 112, no. 4, pp. 1173-1178, Jan. 2015.

A.E. Santoro and K.L. Casciotti, "Enrichment and characterization of ammonia-oxidizing archaea from the open ocean: Phylogeny, physiology, and stable isotope fractionation," ISME J., vol. 5, no. 11, pp. 1796-1808, 2011.

A.E. Santoro et al, "Isotopic composition of N2O produced by marine ammonia-oxidizing archaea," Science, vol. 333, no. 6047, pp. 1282-1285, 2011.

A.E. Santoro et al, "Activity, abundance, and diversity of nitrifying archaea and bacteria in the central California Current," Environ. Microbiol., vol. 12, no. 7, pp. 1989-2006, July 2010.



Associate Fellow Integrated Microbial Biodiversity


University of CaliforniaDepartment of Ecology, Evolution and Marine Biology


Ph.D (Environmental Engineering) Stanford University

MS (Environmental Engineering) Stanford University

BA (Ecology and Evolution) Dartmouth College


United States

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