Differential responses of ammonia-oxidizing archaea and bacteria to long-term fertilization in a New England salt marsh

Abstract

Since the discovery of ammonia-oxidizing archaea (AOA), new questions have arisen about population and community dynamics and potential interactions between AOA and ammonia-oxidizing bacteria (AOB). We investigated the effects of long-term fertilization on AOA and AOB in the Great Sippewissett Marsh, Falmouth, MA, USA to address some of these questions. Sediment samples were collected from low and high marsh habitats in July 2009 from replicate plots that received low (LF), high (HF), and extra high (XF) levels of a mixed NPK fertilizer biweekly during the growing season since 1974. Additional untreated plots were included as controls (C). Terminal restriction fragment length polymorphism analysis of the amoA genes revealed distinct shifts in AOB communities related to fertilization treatment, but the response patterns of AOA were less consistent. Four AOB operational taxonomic units (OTUs) predictably and significantly responded to fertilization, but only one AOA OTU showed a significant pattern. Betaproteobacterial amoA gene sequences within the Nitrosospira-like cluster dominated at C and LF sites, while sequences related to Nitrosomonas spp. dominated at HF and XF sites. We identified some clusters of AOA sequences recovered primarily from high fertilization regimes, but other clusters consisted of sequences recovered from all fertilization treatments, suggesting greater physiological diversity. Surprisingly, fertilization appeared to have little impact on abundance of AOA or AOB. In summary, our data reveal striking patterns for AOA and AOB in response to long-term fertilization, and also suggest a missing link between community composition and abundance and nitrogen processing in the marsh.

Influence of local and regional drivers on spatial and temporal variation of ammonia‐oxidizing communities in Gulf of Mexico salt marshes

“…Nitrosospira ‐related AOB are typically associated with higher salinity and lower organic matter (Francis et al ., ; Bernhard et al ., ; Zhang et al ., ), which were the conditions found at WB where Nitrosospira ‐related AOB dominated. Conversely, Nitrosomonas ‐related AOB are typically associated with higher organic matter and lower salinity (Urakawa et al ., ; Dang et al ., ; Peng et al ., ) and, as expected, these AOB dominated at TB and EB.…”

Resistant ammonia‐oxidizing archaea endure, but adapting ammonia‐oxidizing bacteria thrive in boreal lake sediments receiving nutrient‐rich effluents

“…When unclassified Nitrosomonadacaea was excluded, the abundance of Nitrosomonas was higher than that of Nitrosospira in wastewater‐ influenced sediments. These two AOB clades are physiologically distinct, Nitrosospira ‐like AOB being more abundant in low ammonium conditions, while Nitrosomonas ‐like AOB have been suggested to be adapted to grow in ammonium‐rich environments, for example, in eutrophic sediments (Peng et al ., ; Reis et al ., ). Altogether, these results indicate that although wastewater can promote the abundance of certain AOB groups ( Nitrosomonas ) through habitat modification and migration from WWTP, other groups can still coexist.…”

“…We expected the abundance of AOB to increase in wastewater-influenced sediments, and hypothesized that it would be due to altered environmental conditions and/or introduction of novel AOB from wastewater treatment plant (WWTP). Furthermore, we hypothesized that we would observe a lower diversity in wastewaterinfluenced sediments caused by stronger selection, as there typically is environmental-driven niche differentiation between Nitrosomonas and Nitrosospira groups (e.g., Peng et al, 2013;Zhang et al, 2015). However, we hypothesized that diversity could be promoted, if AOB groups coming from WWTP could successfully colonize the receiving sediments.…”

Long‐term fertilization alters the relative importance of nitrate reduction pathways in salt marsh sediments

“…This is also reflected by the oxygen depth profile in the high marsh of XF plots, which was at about 50% saturation between 1 and 2.5 cm depth, an interval that was completely anoxic in C and HF plots (Figure ). Long‐term fertilization did not increase the abundance of ammonia oxidizers [ Peng et al ., ], suggesting that the per‐cell ammonia oxidation rate was higher in fertilized plots. This response by the ammonia‐oxidizing population was likely a result of more oxidized sediments due to long‐term fertilization (Figure ) [ Howes et al ., ].…”