Spatial variability pattern of the anaerobic ammonia-oxidizing bacterial community across a salinity gradient from river to ocean

Ecotoxicology ◽  
2020 ◽  
Author(s):  
Yiben Li ◽  
Yiguo Hong ◽  
Jiapeng Wu ◽  
Yu Wang ◽  
Fei Ye
Keyword(s):  
Bacterial Community ◽  
Spatial Variability ◽  
Salinity Gradient ◽  
Variability Pattern

scholarly journals Geostatistical integration to improve representativeness of satellite precipitation estimates and field measurements

10.29007/glj1 ◽  
2019 ◽  
Author(s):  
Felipe-Omar Tapia-Silva
Keyword(s):  
Spatial Variability ◽  
Satellite Data ◽  
Field Measurements ◽  
Auxiliary Variable ◽  
Measured Parameter ◽  
Geostatistical Methods ◽  
Variability Pattern ◽  
Distance Weighted ◽  
Precipitation Estimates ◽  
Leave One Out

Since the network of rainfall gauges and ground radars is generally not dense enough, satellite data have been used to estimate Precipitation (P). These data have the ability to capture the spatial variability pattern of the parameter, but are often inaccurate in relation to the value of the field measured parameter. Therefore, geostatistical methods were evaluated to improve the spatial representativeness of field measurements (FM) and satellite estimates. The work has been made for a hydrological sub region in the Mexican tropic. The geostatistical methods used to interpolate P-FM were ordinary kriging (KO), universal kriging (KU) and regression kriging (RK) as well as the Inverse Distance Weighted (IDW) mechanical interpolator for comparison purposes. Furthermore, the values at the pixel centers of the Tropical Rainfall Monitoring Mission (TRMM) images were interpolated using OK and evaluated using leave-one-out cross validation (LOO-CV). The best LOO-CV evaluated method consisted of the RK interpolation of the point FM taking as auxiliary variable the OK interpolation of the TRMM cell centers. It is concluded that the geostatistical integration between rainfall estimates from satellite data and FM data is promising because satellite information has the ability to capture spatial variability and the point FM add accuracy to the results. These characteristics combined can produce a P product useful for modeling activities and environmental management.

scholarly journals Spatial Variability Pattern of Hyporheic Exchange in a braided River

2018 ◽  
Vol 246 ◽  
pp. 01098
Author(s):  
Guangdong Wu ◽  
Xiao Zhang ◽  
Jijun Xu
Keyword(s):  
Spatial Variability ◽  
Flow System ◽  
Hyporheic Exchange ◽  
Braided River ◽  
Downward Flow ◽  
One Dimensional ◽  
Physical Mechanisms ◽  
Braided Channel ◽  
Variability Pattern ◽  
Heat As A Tracer

The streambed flux is variable in space; the spatial variability results in part from bedforms, but few works on streambed fluxes in channels with strongly abrupt varying bedforms are carried out. Heat as a tracer to delineate the streambed flux pattern has been widely adopted in numerous fields. In this paper, a braided channel with complicated topography was selected as study site, where the temperature was monitored. One-dimensional (1-D) analytical method based on the amplitude attenuation (Ar) and 1-D numerical method were used to interpret the temperature. As a result, streambed fluxes of a total of 50 sites in the braided channel are obtained. From the results we can know the magnitude and direction of streamed flow velocity are spatially variable, even within a 1-m distance. Then, this study summarizes five bedform-driven flux patterns: ① downward flow driven by the head difference between groundwater and stream, ② downward flow related to a meter-scale pool, ③ a transition from upward to downward flow associated with a centimeter-scale riffle, ④ horizontal flow in braided bars and ⑤ upward flow driven by vegetation roots. Overall, multiple physical mechanisms together contributed to the complex streambed flow system, which reflected great challenges for the scaling up of point-in-space seepage flux.

scholarly journals Suscetibilidade magnética na caracterização da variabilidade espacial de atributos do solo em solos subtropicais

2021 ◽  
Vol 43 ◽  
pp. e47
Author(s):  
Priscila Vogelei Ramos ◽  
Ricardo Simão Diniz Dalmolin ◽  
Jean Michel Moura-Bueno ◽  
José Marques Junior ◽  
Diego Silva Siqueira ◽  
...  
Keyword(s):  
Spatial Variability ◽  
Spatial Variation ◽  
Spatial Dependence ◽  
Clay Soil ◽  
Pearson Correlation ◽  
Soil Attributes ◽  
Variability Pattern ◽  
Sample Density ◽  
Basaltic Soils ◽  
Future Work

Magnetic susceptibility (MS) has been used to estimate soil attributes. With the proposal to increase the information of soils in southern Brazil the objectives of this work were: (i) evaluate the correlation of SM with soil attributes in a slope of subtropical basaltic soils; (ii) to characterize the spatial variation structure of MS and the content of sand, clay and COS; and (iii) identify the sample density that captures the spatial variability to assist future work under similar conditions. In a 22 ha area located in Santo Augusto - RS, Brazil, an 87 points sample grid was collected to determine soil attributes. Samples were also collected in five profiles along the slope. The profile data were analyzed by correlation to verify the degree of Pearson correlation of the SM with the attributes of the soil. In the sample grid spatial dependence analyzes were performed to assess the degree of spatial dependence on soil attributes. The MS presented a high correlation with the attributes of clay soil, Fes, Fed and COS. The evaluation of the spatial variation structure showed that the attributes presented a degree of spatial dependence ranging from weak for COS to strong for MS. The spatial variability pattern suggests a sample density of one point every 4 to 12 ha.

Bacterial community changes along a salinity gradient in a Chinese wetland

2013 ◽  
Vol 59 (9) ◽  
pp. 611-619 ◽  
Author(s):  
Lei Zhang ◽  
Guang Gao ◽  
Xiangming Tang ◽  
Keqiang Shao ◽  
Sai Bayartu ◽  
...  
Keyword(s):  
Bacterial Community ◽  
Salinity Gradient ◽  
Sharp Decrease ◽  
Northwest China ◽  
Community Response ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Salinity Range ◽  
Small Scale ◽  
Salinity Levels

We analyzed the composition and diversity of a bacterial community to determine its response to increasing salinity in the Xiangsi Lake wetland in the arid region of northwest China. We studied 12 sites, ranging from freshwater to saltwater habitats, using polymerase chain reaction (PCR)-based terminal restriction fragment length polymorphism (T-RFLP) and sequencing of the 16S rRNA genes of 5 selected samples. Cluster analysis and phylogenetic analysis revealed that the bacterial community changed significantly in response to increased salinity within the small-scale wetland (50.8 km2). Detailed analysis showed that (i) Betaproteobacteria can maintain balanced growth over a salinity range (from 0.34 to 6.86 g/L) through intergenus changes in community structure, followed by a sharp decrease in relative abundance (from 62.2% to 16.0%) when salinity reaches 26.18 g/L; (ii) salt-sensitive and halophobic taxa were progressively replaced by halotolerant and halophilic taxa with increasing salinity; (iii) bacterial diversity was lowest at intermediate salinity levels (6.86 g/L); and (iv) an increasing percentage of unclassified bacterial taxa were found with increasing salinity. This study has implications to improve understanding of bacterial community response to water salinization.

scholarly journals Microbial Biogeography along an Estuarine Salinity Gradient: Combined Influences of Bacterial Growth and Residence Time

2004 ◽  
Vol 70 (3) ◽  
pp. 1494-1505 ◽  
Author(s):  
Byron C. Crump ◽  
Charles S. Hopkinson ◽  
Mitchell L. Sogin ◽  
John E. Hobbie
Keyword(s):  
Bacterial Community ◽  
Community Composition ◽  
Residence Time ◽  
Doubling Time ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Salinity Gradient ◽  
Bacterial Community Composition ◽  
River Estuary ◽  
Leucine Incorporation ◽  
Bacterioplankton Community

ABSTRACT Shifts in bacterioplankton community composition along the salinity gradient of the Parker River estuary and Plum Island Sound, in northeastern Massachusetts, were related to residence time and bacterial community doubling time in spring, summer, and fall seasons. Bacterial community composition was characterized with denaturing gradient gel electrophoresis (DGGE) of PCR-amplified 16S ribosomal DNA. Average community doubling time was calculated from bacterial production ([14C]leucine incorporation) and bacterial abundance (direct counts). Freshwater and marine populations advected into the estuary represented a large fraction of the bacterioplankton community in all seasons. However, a unique estuarine community formed at intermediate salinities in summer and fall, when average doubling time was much shorter than water residence time, but not in spring, when doubling time was similar to residence time. Sequencing of DNA in DGGE bands demonstrated that most bands represented single phylotypes and that matching bands from different samples represented identical phylotypes. Most river and coastal ocean bacterioplankton were members of common freshwater and marine phylogenetic clusters within the phyla Proteobacteria, Bacteroidetes, and Actinobacteria. Estuarine bacterioplankton also belonged to these phyla but were related to clones and isolates from several different environments, including marine water columns, freshwater sediments, and soil.

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