Hannah Geiser, Goshen College

Class Year:



Alyson Santoro, Ph.D.


Project Title:

Presence of Ammonia-Oxidizing Archaea and Bacteria along Physiochemical Gradients in Coastal Beaches and Estuaries


Coastal intertidal estuaries in California and Maryland were analyzed for the presence of ammonia-oxidizing archaea and bacteria and correlation with dissolved inorganic nitrogen removal. DNA was extracted from sediment samples and real-time polymerase chain reaction was used to quantify the presence of the amoA gene subunit, a portion of the gene that encodes for the conversion of ammonia to hydroxylamine. Ammonia-oxidizing archaea and bacteria were found with relatively more archaea in the coastal sediments. The abundance of ammonia-oxidizing bacteria appeared to correlate with dissolved oxygen. Removal of dissolved inorganic nitrogen did not appear to be limited by the abundance of microbes found in the sediment.


Geiser, H.*, N. de Sieyes, A. Boehm, and A. Santoro. 2013. Distribution of ammonia-oxidizing archaea and bacteria along physiochemical gradients at subterranean estuaries in California and Maryland. ASLO Aquatic Sciences Meeting, New Orleans, Louisiana.

The REU students are indicated with an asterisk (*).

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