AME 79:31-48 (2017)  -  DOI: https://doi.org/10.3354/ame01817

Aerobic and anaerobic ammonium oxidizers in the Cariaco Basin: distributions of major taxa and nitrogen species across the redoxcline

Sara Cernadas-Martín1,*, Elizabeth A. Suter1, Mary I. Scranton1, Yrene Astor2, Gordon T. Taylor1

1School of Marine and Atmospheric Sciences, 145 Endeavour Hall, Stony Brook University, Stony Brook, New York 11794-5000, USA
2Estacion de Investigaciones Marinas de Margarita, Fundación la Salle de Ciencias Naturales, Apartado 144, Punta de Piedras, Estado Nueva Esparta 06318, Venezuela
*Corresponding author:

ABSTRACT: Depth distributions of cells and functional gene copies from anaerobic ammonium-oxidizing (anammox) bacteria, aerobic ammonium-oxidizing bacteria (AOB) and archaea (AOA) in the Cariaco Basin, Venezuela were obtained using FISH and q-PCR assays. These distributions were compared to concentrations of dissolved ammonium (NH4+), nitrite (NO2-), nitrate (NO3-), hydrogen sulfide (H2S) and oxygen (O2) along the redoxcline during 3 cruises. Cell counts of anammox bacteria and copies of their nitrite reductase gene (Scalindua-nirS) were consistently observed in 2 distinct layers: the suboxic zone (≤1.1 × 106 cells l-1) and the upper euxinic zone (≤4.7 × 106 cells l-1). We hypothesize that anammox bacteria vertically organize in response to NO2- sources, with NO2- for the shallower assemblage supplied by nitrification and for the deeper assemblage by denitrification. Peaks in AOA cell abundances (up to 14.8 × 106 cells l-1) consistently coincided with copy numbers of archaeal ammonia monooxygenase subunit A gene (archaeal amoA) in the lower oxic zone. Peak abundances of beta- and gammaproteobacterial AOB cells (up to 24.0 × 106 cells l-1) and one of their ammonia monooxygenase genes (β-amoA) overlapped above the shallow anammox peak. Our results suggest that anammox bacteria AOB, AOA and denitrifiers are metabolically interdependent and ultimately controlled by vertical fluxes of O2, NO3-, NO2-, and NH4+ in the Cariaco Basin.


KEY WORDS: Anammox · Ammonium oxidation · Cariaco · q-PCR · FISH · Nutrient flux


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Cite this article as: Cernadas-Martín S, Suter EA, Scranton MI, Astor Y, Taylor GT (2017) Aerobic and anaerobic ammonium oxidizers in the Cariaco Basin: distributions of major taxa and nitrogen species across the redoxcline. Aquat Microb Ecol 79:31-48. https://doi.org/10.3354/ame01817

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