Summary

• Main Authors: Karen M. Kalanetra, Nasreen Bano, James T. Hollibaugh
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Antarctic; Antarctic Peninsula; Arctic; Arctic Ocean; Southern Ocean; The Antarctic; Antarc*
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.456.8901; http://pal.lternet.edu/docs/bibliography/Public/384lterc.pdf

We compared abundance, distributions and phyloge-netic composition of Crenarchaeota and ammonia-oxidizing Archaea (AOA) in samples collected from coastal waters west of the Antarctic Peninsula during the summers of 2005 and 2006, with samples from the central Arctic Ocean collected during the summer of 1997. Ammonia-oxidizing Archaea and Crenarchaeota abundances were estimated from quantitative PCR measurements of amoA and 16S rRNA gene abundances. Crenarchaeota and AOA were approximately fivefold more abundant at com-parable depths in the Antarctic versus the Arctic Ocean. Crenarchaeota and AOA were essentially absent from the Antarctic Summer Surface Water (SSW) water mass (0–45 m depth). The ratio of Cre-narchaeota 16S rRNA to archaeal amoA gene abun-dance in the Winter Water (WW) water mass (45– 105 m depth) of the Southern Ocean was much lower (0.15) than expected and in sharp contrast to the ratio (2.0) in the Circumpolar Deep Water (CDW) water mass (105–3500 m depth) immediately below it. We did not observe comparable segregation of this ratio by depth or water mass in Arctic Ocean samples. A ubiquitous, abundant and polar-specific crenarchaeote was the dominant ribotype in the WW and important in the upper halocline of the Arctic Ocean. Our data suggest that this organism does not contain an ammonia monooxygenase gene. In con-trast to other studies where Crenarchaeota popula-tions apparently lacking amoA genes are found in bathypelagic waters, this organism appears to domi-nate in well-defined, ammonium-rich, near-surface water masses in polar oceans.