• Publications
  • Influence
Ubiquity and diversity of ammonia-oxidizing archaea in water columns and sediments of the ocean.
Using PCR primers designed to specifically target archaeal amoA, AOA is found to be pervasive in areas of the ocean that are critical for the global nitrogen cycle, including the base of the euphotic zone, suboxic water columns, and estuarine and coastal sediments. Expand
New processes and players in the nitrogen cycle: the microbial ecology of anaerobic and archaeal ammonia oxidation
What is currently known about the microbial ecology of anaerobic and archaeal ammonia oxidation is reviewed, relevant unknowns are highlighted, and the implications of these discoveries for the global nitrogen and carbon cycles are discussed. Expand
Molecular and biogeochemical evidence for ammonia oxidation by marine Crenarchaeota in the Gulf of California
Direct quantification of ammonia oxidation rates by 15N labeling, and AOA and AOB abundances by quantitative PCR analysis of ammonia monooxygenase subunit A (amoA) genes, in the Gulf of California represent compelling evidence for an archaeal role in oceanic nitrification. Expand
Diversity of Ammonia-Oxidizing Archaea and Bacteria in the Sediments of a Hypernutrified Subtropical Estuary: Bahía del Tóbari, Mexico
  • J. Beman, C. Francis
  • Medicine, Biology
  • Applied and Environmental Microbiology
  • 29 September 2006
These findings represent the first detailed examination of archaeal amoA diversity in estuarine sediments and demonstrate that diverse communities of Crenarchaeota capable of ammonia oxidation are present within estuaries, where they may be actively involved in nitrification. Expand
Global declines in oceanic nitrification rates as a consequence of ocean acidification
It is suggested that ocean acidification could reduce nitrification rates by 3–44% within the next few decades, affecting oceanic nitrous oxide production, reducing supplies of oxidized nitrogen in the upper layers of the ocean, and fundamentally altering nitrogen cycling in the sea. Expand
Marine bacterial, archaeal and protistan association networks reveal ecological linkages
The analysis revealed a progression of microbial communities through time, and also a group of unknown eukaryotes that were highly correlated with dinoflagellates, indicating possible symbioses or parasitism, and a network generated from these statistical correlations provides new insights into the natural history of microbes. Expand
Oceanographic and biological effects of shoaling of the oxygen minimum zone.
Olympic oxygen minimum zones have expanded over the past 50 years, and this expansion is predicted to continue as the climate warms worldwide, and shoaling of the upper boundaries of the OMZs accompanies OMZ expansion. Expand
Quantification of ammonia oxidation rates and ammonia‐oxidizing archaea and bacteria at high resolution in the Gulf of California and eastern tropical North Pacific Ocean
Ammonia is rapidly oxidized within discrete depth intervals in the GOC and ETNP; while pyrosequencing and QPCR demonstrate that AOB are confined to deeper portions of the water column, AOA appear to be active within the euphotic zone, where they may quickly respond to nitrogen inputs. Expand
Agricultural runoff fuels large phytoplankton blooms in vulnerable areas of the ocean
It is demonstrated that nitrogen-deficient areas of the tropical and subtropical oceans are acutely vulnerable to nitrogen pollution, and it is projected that by the year 2050, 27–59% of all nitrogen fertilizer will be applied in developing regions located upstream of nitrogen- deficient marine ecosystems. Expand