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University of Waterloo

1. Sauder, Laura. Ammonia-oxidizing archaea in engineered biofiltration systems.

Degree: 2016, University of Waterloo

Ammonia is a nitrogenous metabolic waste product that is produced by all animal life. High concentrations of ammonia are toxic to animals and may result in algal blooms and eutrophication in aquatic environments. To prevent negative impacts on animal and environmental health, water treatment systems use biological filters to host populations of nitrifying microorganisms that oxidize ammonia to nitrite and subsequently to nitrate. Ammonia-oxidizing archaea (AOA) outnumber ammonia-oxidizing bacteria (AOB) in many terrestrial and aquatic environments, but few studies have characterized AOA in engineered environments, despite the importance of these systems for ecosystem health. This thesis research examined two types of nitrifying biofiltration systems, including freshwater aquaria and fixed-film reactors from a municipal wastewater treatment plant (WWTP), to investigate the abundance, diversity, activity, and ecology of AOA in freshwater engineered systems. Although nitrification is the primary function of aquarium biofilters, few studies have investigated the microorganisms responsible for this process in aquaria. Based on quantitative PCR (qPCR) for ammonia monooxygenase (amoA) and 16S rRNA genes of Bacteria and Thaumarchaeota, AOA were numerically dominant in 23 of 27 freshwater biofilters, and contributed all detectable amoA genes in 12 of these biofilters. AOA also outnumbered AOB in five of eight sampled marine aquarium biofilters. For freshwater aquaria, the proportion of amoA genes from AOA relative to AOB was inversely correlated with ammonia concentration, suggesting an adaptation to low ammonia conditions. Composite clone libraries of AOA amoA genes revealed distinct freshwater and saltwater clusters, as well as mixed clusters containing both freshwater and saltwater amoA gene sequences. From one analyzed freshwater aquarium biofilter that demonstrated a high archaeal abundance, AOA representative Candidatus Nitrosotenius aquariensis was enriched in laboratory culture. Ca. N. aquariensis oxidized ammonia stoichiometrically to nitrite with a concomitant increase in thaumarchaeotal cells. Ca. N. aquariensis has a generation time of 34.9 hours, is mesophilic with an optimal growth temperature of 33ᵒC, and can tolerate up to 3 mM NH4Cl. Transmission electron microscopy (TEM) revealed that Ca. N. aquariensis cells are rod-shaped with a diameter of ~0.4 µm and lengths ranging from 0.6-3.6 µm. In addition, these cells possess paracrystalline S-layers and up to five appendages per cell. Phylogenetically, Ca. N. aquariensis belongs to the Group I.1a Thaumarchaeota, and clusters with environmental sequences from freshwater aquarium biofilters, aquaculture systems, and wastewater treatment plants (WWTPs). The complete genome sequence is 1.70 Mbp, and encodes genes involved in ammonia oxidation, urea hydrolysis, and bicarbonate assimilation. Several genes encoding flagella synthesis and chemotaxis were identified in the genome, as well as genes associated with S-layer production, defense, and protein glycosylation.…

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APA (6th Edition):

Sauder, L. (2016). Ammonia-oxidizing archaea in engineered biofiltration systems. (Thesis). University of Waterloo. Retrieved from http://hdl.handle.net/10012/11128

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Sauder, Laura. “Ammonia-oxidizing archaea in engineered biofiltration systems.” 2016. Thesis, University of Waterloo. Accessed January 23, 2017. http://hdl.handle.net/10012/11128.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Sauder, Laura. “Ammonia-oxidizing archaea in engineered biofiltration systems.” 2016. Web. 23 Jan 2017.

Vancouver:

Sauder L. Ammonia-oxidizing archaea in engineered biofiltration systems. [Internet] [Thesis]. University of Waterloo; 2016. [cited 2017 Jan 23]. Available from: http://hdl.handle.net/10012/11128.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Sauder L. Ammonia-oxidizing archaea in engineered biofiltration systems. [Thesis]. University of Waterloo; 2016. Available from: http://hdl.handle.net/10012/11128

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

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