scholarly journals Different Driving Factors for Potential Activity of Ammonia-Oxidizing Archaea and Bacteria in Coastal Wetlands

2021 ◽  
Author(s):  
Xianfang zhu ◽  
Chen Wang ◽  
Shuangyu Tang ◽  
Guodong Ji
Keyword(s):  
Nitrogen Cycle ◽  
Coastal Wetlands ◽  
Ammonia Oxidation ◽  
Equation Model ◽  
Ammonium Concentration ◽  
Ammonia Oxidizing Archaea ◽  
Soil Sediment ◽  
Measured Activity ◽  
Structure Equation Model ◽  
Potential Activity

Abstract This study aimed to evaluate which environmental factors and genetic groups were important in explaining measured activity of Ammonia-oxidizing archaea (AOA) and bacteria (AOB), which play important roles in global nitrogen cycle, providing a new insight into the mechanism of archaeal and bacterial ammonia oxidation. We sampled 62 soil/sediment samples from coastal wetlands of the Bohai area of China and assessed the abundance of functional genes involved in the nitrogen cycle, soil/sediment characteristics and the potential activity of AOA (PAOA) and AOB (PAOB) using specific inhibitors. At last, we introduced the structure equation model (SEM) to infer direct and indirect effects of variables on potential activities. The results indicated that the change in AOA-amoA gene abundance may be more independent, while AOB-amoA was closely associated with the change in abundance of amx and denitrifier. PAOA was mainly defined by AOA-amoA abundance and partially influenced by the norA gene, suggesting coupling of archaeal ammonia oxidation with nitrite oxidation. PAOB was significantly defined by the abundance of amx and denitrifier, indirectly mediated by AOB-amoA. The activity of AOA seemed to be more independent of other microbial activities, while the activity of AOB varied closely with fluctuations of other microbial species. PAOA was mediated directly by the C/N ratio and indirectly by nitrite concentration and TOC value, while PAOB was mediated directly by ammonium concentration and TOC value and indirectly by C/N ratio. The activity of AOB may be determined by several other functional gene groups and had little correlation with AOB abundance while the activity of AOA was mostly controlled by itself.

Competition of Ammonia-Oxidizing Archaea and Bacteria from Freshwater Environments

2021 ◽  
Author(s):  
Elizabeth French ◽  
Jessica A. Kozlowski ◽  
Annette Bollmann
Keyword(s):  
Ammonia Oxidation ◽  
Heterotrophic Bacteria ◽  
Ammonia Oxidizer ◽  
Ammonium Concentration ◽  
Natural Environments ◽  
Ammonia Oxidizing Bacteria ◽  
Ammonia Oxidizers ◽  
Batch Cultures ◽  
Freshwater Systems ◽  
Ammonia Oxidizing Archaea

In the environment, nutrients are rarely available in constant supply. Therefore, microorganisms require strategies to compete for limiting nutrients. In freshwater systems, ammonia-oxidizing archaea (AOA) and bacteria (AOB) compete with heterotrophic bacteria, photosynthetic microorganisms, and each other for ammonium, which AOA and AOB utilize as their sole source of energy and nitrogen. We investigated the competition between highly enriched cultures of an AOA (AOA-AC1) and an AOB (AOB-G5-7) for ammonium. Based on the amoA gene, the newly enriched archaeal ammonia oxidizer in AOA-AC1 was closely related to Nitrosotenuis spp. and the bacterial ammonia oxidizer in AOB-G5-7, Nitrosomonas sp. Is79, belonged to the Nitrosomonas oligotropha group ( Nitrosomonas cluster 6a). Growth experiments in batch cultures showed that AOB-G5-7 had higher growth rates than AOA-AC1 at higher ammonium concentrations. During chemostat competition experiments under ammonium-limiting conditions, AOA-AC1 dominated the cultures, while AOB-G5-7 decreased in abundance. In batch cultures, the outcome of the competition between AOA and AOB was determined by the initial ammonium concentrations. AOA-AC1 was the dominant ammonia oxidizer at an initial ammonium concentration of 50 μM and AOB-G5-7 at 500 μM. These findings indicate that, during direct competition, AOA-AC1 was able to use ammonium that was unavailable to AOB-G5-7, while AOB-G5-7 dominated at higher ammonium concentrations. The results are in strong accordance with environmental survey data suggesting that AOA are mainly responsible for ammonia oxidation under more oligotrophic conditions, whereas AOB dominate under eutrophic conditions. Importance Nitrification is an important process in the global nitrogen cycle. The first step - ammonia oxidation to nitrite – can be carried out by Ammonia-oxidizing Archaea (AOA) and Ammonia-oxidizing Bacteria (AOB). In many natural environments, these ammonia oxidizers coexist. Therefore, it is important to understand the population dynamics in response to increasing ammonium concentrations. Here, we study the competition between AOA and AOB enriched from freshwater systems. The results demonstrate that AOA are more abundant in systems with low ammonium availabilities and AOB when the ammonium availability increases. These results will help to predict potential shifts in community composition of ammonia oxidizers in the environment due to changes in ammonium availability.

scholarly journals Ammonia Oxidizers in High-Elevation Rivers of the Qinghai-Tibet Plateau Display Distinctive Distribution Patterns

2019 ◽  
Vol 85 (22) ◽  
Author(s):  
Sibo Zhang ◽  
Xinghui Xia ◽  
Siling Li ◽  
Liwei Zhang ◽  
Gongqin Wang ◽  
...  
Keyword(s):  
Low Temperature ◽  
Solar Radiation ◽  
Nitrogen Cycle ◽  
Ammonia Oxidation ◽  
Distribution Patterns ◽  
High Elevation ◽  
Tibet Plateau ◽  
Ammonium Concentration ◽  
Ammonia Oxidizers ◽  
Qinghai Tibet Plateau

ABSTRACT Ammonia-oxidizing bacteria (AOB) and archaea (AOA) as well as comammox catalyze ammonia oxidation. The distribution and biogeography of these ammonia oxidizers might be distinctive in high-elevation rivers, which are generally characterized by low temperature and low ammonium concentration but strong solar radiation; however, these characteristics have rarely been documented. This study explored the abundance, community, and activity of ammonia oxidizers in the overlying water of five rivers in the Qinghai-Tibet Plateau (QTP). Potential nitrification rates in these rivers ranged from 5.4 to 38.4 nmol N liter−1 h−1, and they were significantly correlated with ammonium concentration rather than temperature. Comammox were found in 25 of the total 28 samples, and they outnumbered AOA in three samples. Contrary to most studied low-elevation rivers, average AOB amoA gene abundance was significantly higher than that of AOA, and AOB/AOA ratios increased with decreasing water temperature. The Simpson index of the AOA community increased with elevation (P < 0.05), and AOA and AOB communities exhibited high dissimilarities with low-elevation rivers. Cold-adapted (Nitrosospira amoA cluster 1, 33.6%) and oligotrophic (Nitrosomonas amoA cluster 6a, 31.7%) groups accounted for large proportions in the AOB community. Suspended sediment concentration exerted significant effects on ammonia oxidizer abundance (r > 0.56), and owing to their elevational variations in source and concentration, suspended sediments facilitated distance-decay patterns for AOA and AOB community similarities. This study demonstrates distinctive biogeography and distribution patterns for ammonia oxidizers in high-elevation rivers of the QTP. Extensive research should be conducted to explore the role of these microbes in the nitrogen cycle of this zone. IMPORTANCE Ammonia-oxidizing archaea (AOA) and bacteria (AOB) as well as comammox contribute to ammonia oxidation, which plays significant roles in riverine nitrogen cycle and N2O production. Source regions of numerous rivers in the world lie in high-elevation zones, but the abundance, community, and activity of ammonia oxidizers in rivers in high-elevation regions have rarely been investigated. This study revealed distinctive distribution patterns and community structures for ammonia oxidizers in five high-elevation rivers of the Qinghai-Tibet Plateau, and the individual and combined effects of low temperature, low nutrients, and strong solar radiation on ammonia oxidizers were elucidated. The findings of this study are helpful to broaden our knowledge on the biogeography and distribution pattern of ammonia oxidizers in river systems. Moreover, this study provides some implications to predict the performance of ammonia oxidizers in high-elevation rivers and its variations under global climate warming.

scholarly journals Ammonia-oxidizing archaea are integral to nitrogen cycling in a highly fertile agricultural soil

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Laibin Huang ◽  
Seemanti Chakrabarti ◽  
Jennifer Cooper ◽  
Ana Perez ◽  
Sophia M. John ◽  
...  
Keyword(s):  
Nitrogen Cycle ◽  
Agricultural Soil ◽  
Agricultural Soils ◽  
Ammonia Oxidizing Bacteria ◽  
Central Process ◽  
Soil Nitrification ◽  
Plant Nitrogen ◽  
Ammonia Oxidizing Archaea ◽  
Activity Measurements ◽  
Nitrite Oxidizing Bacteria

AbstractNitrification is a central process in the global nitrogen cycle, carried out by a complex network of ammonia-oxidizing archaea (AOA), ammonia-oxidizing bacteria (AOB), complete ammonia-oxidizing (comammox) bacteria, and nitrite-oxidizing bacteria (NOB). Nitrification is responsible for significant nitrogen leaching and N2O emissions and thought to impede plant nitrogen use efficiency in agricultural systems. However, the actual contribution of each nitrifier group to net rates and N2O emissions remain poorly understood. We hypothesized that highly fertile agricultural soils with high organic matter mineralization rates could allow a detailed characterization of N cycling in these soils. Using a combination of molecular and activity measurements, we show that in a mixed AOA, AOB, and comammox community, AOA outnumbered low diversity assemblages of AOB and comammox 50- to 430-fold, and strongly dominated net nitrification activities with low N2O yields between 0.18 and 0.41 ng N2O–N per µg NOx–N in cropped, fallow, as well as native soil. Nitrification rates were not significantly different in plant-covered and fallow plots. Mass balance calculations indicated that plants relied heavily on nitrate, and not ammonium as primary nitrogen source in these soils. Together, these results imply AOA as integral part of the nitrogen cycle in a highly fertile agricultural soil.

scholarly journals Soil ammonia-oxidizing archaea in a paddy field with different irrigation and fertilization managements

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Limin Wang ◽  
Dongfeng Huang
Keyword(s):  
Ammonia Oxidation ◽  
Chemical Properties ◽  
Paddy Soils ◽  
Soil Nitrification ◽  
Treated Soil ◽  
Ammonia Oxidizing Archaea ◽  
Rice Yields ◽  
Traditional Irrigation ◽  
Almost All ◽  
And Function

AbstractBecause ammonia-oxidizing archaea (AOA) are ubiquitous and highly abundant in almost all terrestrial soils, they play an important role in soil nitrification. However, the changes in the structure and function of AOA communities and their edaphic drivers in paddy soils under different fertilization and irrigation regimes remain unclear. In this study, we investigated AOA abundance, diversity and activity in acid paddy soils by a field experiment. Results indicated that the highest potential ammonia oxidation (PAO) (0.011 μg NO 2 -  –N g-1 d.w.day-1) was found in T2 (optimal irrigation and fertilization)—treated soils, whereas the lowest PAO (0.004 μg NO 2 -  –N g-1 d.w.day-1) in T0 (traditional irrigation)- treated soils. Compared with the T0—treated soil, the T2 treatment significantly (P < 0.05) increased AOA abundances. Furthermore, the abundance of AOA was significantly (P < 0.01) positively correlated with pH, soil organic carbon (SOC), and PAO. Meanwhile, pH and SOC content were significantly (P < 0.05) higher in the T2—treated soil than those in the T1 (traditional irrigation and fertilization)- treated soil. In addition, these two edaphic factors further influenced the AOA community composition. The AOA phylum Crenarchaeota was mainly found in the T2—treated soils. Phylogenetic analysis revealed that most of the identified OTUs of AOA were mainly affiliated with Crenarchaeota. Furthermore, the T2 treatment had higher rice yield than the T0 and T1 treatments. Together, our findings confirm that T2 might ameliorate soil chemical properties, regulate the AOA community structure, increase the AOA abundance, enhance PAO and consequently maintain rice yields in the present study.

scholarly journals The Mechanism of Corporate Governance, Financial Performance, and Social Performance in Baitul Maal Wat Tamwil (BMT)

2020 ◽  
Vol 3 (1) ◽  
pp. 1-17
Author(s):  
Hasan Mukhibad ◽  
Akhmad Nurkhin
Keyword(s):  
Financial Performance ◽  
Significant Influence ◽  
Social Performance ◽  
Supervisory Board ◽  
Equation Model ◽  
Education Level ◽  
Structure Equation Model ◽  
Supervisory Boards ◽  
Observation Period

This study aimed to empirically prove the influence of the number and education level of managers, supervisory boards, Sharia Supervisory Board (SSB) and the attendance of Baitul Maal wat Tamwil (BMT) members (owners) in annual member meeting towards on profitability (ROA and ROE), and social performance (zakat performance). The research sample was BMT in Semarang Regency selected by purposive sampling method with an observation period from 2013 to 2017. Data analysis used the Structure Equation Model with the WarpPLS tool. The results showed that the number and education level of managers did not influence financial performance. The education level of the supervisory board had a significant influence on financial and social performance. The number and the education level of SSB changed financial performance, but the education level of SSB did not affect social performance. The Attendance of BMT members at the annual member meeting did not have a significant influence on BMT's financial and social performance improvement. These results indicated the minimal role of members in evaluating BMT performance, both profitability and social performance.

scholarly journals Measurements of nitrite production in and around the primary nitrite maximum in the central California Current

2013 ◽  
Vol 10 (11) ◽  
pp. 7395-7410 ◽  
Author(s):  
A. E. Santoro ◽  
C. M. Sakamoto ◽  
J. M. Smith ◽  
J. N. Plant ◽  
A. L. Gehman ◽  
...  
Keyword(s):  
Ammonia Oxidation ◽  
Heterotrophic Bacteria ◽  
California Current ◽  
Euphotic Zone ◽  
Ammonia Oxidizing Bacteria ◽  
Central California ◽  
Oxidation Rates ◽  
Ammonia Oxidizing Archaea ◽  
Nitrite Production ◽  
Nh3 Oxidation

Abstract. Nitrite (NO2−) is a substrate for both oxidative and reductive microbial metabolism. NO2− accumulates at the base of the euphotic zone in oxygenated, stratified open-ocean water columns, forming a feature known as the primary nitrite maximum (PNM). Potential pathways of NO2− production include the oxidation of ammonia (NH3) by ammonia-oxidizing bacteria and archaea as well as assimilatory nitrate (NO3−) reduction by phytoplankton and heterotrophic bacteria. Measurements of NH3 oxidation and NO3− reduction to NO2− were conducted at two stations in the central California Current in the eastern North Pacific to determine the relative contributions of these processes to NO2− production in the PNM. Sensitive (< 10 nmol L−1), precise measurements of [NH4+] and [NO2−] indicated a persistent NH4+ maximum overlying the PNM at every station, with concentrations as high as 1.5 μmol L−1. Within and just below the PNM, NH3 oxidation was the dominant NO2− producing process, with rates of NH3 oxidation to NO2− of up to 31 nmol L−1 d−1, coinciding with high abundances of ammonia-oxidizing archaea. Though little NO2− production from NO3− was detected, potentially nitrate-reducing phytoplankton (photosynthetic picoeukaryotes, Synechococcus, and Prochlorococcus) were present at the depth of the PNM. Rates of NO2− production from NO3− were highest within the upper mixed layer (4.6 nmol L−1 d−1) but were either below detection limits or 10 times lower than NH3 oxidation rates around the PNM. One-dimensional modeling of water column NO2− production agreed with production determined from 15N bottle incubations within the PNM, but a modeled net biological sink for NO2− just below the PNM was not captured in the incubations. Residence time estimates of NO2− within the PNM ranged from 18 to 470 days at the mesotrophic station and was 40 days at the oligotrophic station. Our results suggest the PNM is a dynamic, rather than relict, feature with a source term dominated by ammonia oxidation.

Gender-Role Interaction in Activity Participation between Nuclear Household Heads: A Case Study of Suzhou

2012 ◽  
Vol 209-211 ◽  
pp. 735-741
Author(s):  
Jing Yao Zhao ◽  
Wei Wang ◽  
Min Yang
Keyword(s):  
Gender Role ◽  
Travel Behavior ◽  
Leisure Activity ◽  
Equation Model ◽  
Activity Participation ◽  
Male And Female ◽  
Structure Equation Model ◽  
Household Heads ◽  
Nuclear Household

Based on the 1235 cases of data collected in the survey of Suzhou, a structure equation model is developed to evaluate how gender-role interactions occur in two levels: attribute-activity and activity participation itself. The results show that those two kinds of interactions between two household heads do exist and strongly affect each other’s subsistence, maintenance and leisure activity participations. Household attributes and children’s age are found to have different effect on male and female heads. It indicates that one important reason for male and female differ in activity-travel behavior is that they receive different interactions in household from counterparts. As expected, those results show that different TDM policies should be made aiming at women and men. It will help to better reflect the behavioral responses of household heads to changes in demographic characteristics and to get a deeper understanding of gender difference in activity behavior in developing countries.

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