scholarly journals Spatial and Temporal Variation in Microbial Diversity and Community Structure in a Contaminated Mangrove Wetland

2020 ◽  
Vol 10 (17) ◽  
pp. 5850
Author(s):  
Jiaojiao Ma ◽  
Ting Zhou ◽  
Chunyu Xu ◽  
Dawen Shen ◽  
Songjun Xu ◽  
...  
Keyword(s):  
Community Structure ◽  
Spatial Variation ◽  
Temporal Variation ◽  
Bacterial Diversity ◽  
Diversity Index ◽  
Total Carbon ◽  
Spatial And Temporal Variation ◽  
Rrna Gene ◽  
Mangrove Wetland ◽  
Mangrove Soils

Field and laboratory investigations were conducted to characterize bacterial diversity and community structure in a badly contaminated mangrove wetland adjacent to the metropolitan area of a megacity in subtropical China. Next-generation sequencing technique was used for sequencing the V4–V5 region of the 16s rRNA gene on the Illumina system. Collectively, Proteobacteria, Chloroflexi, Planctomycetes, Actinobacteria and Bacteroidetes were the predominant phyla identified in the investigated soils. A significant spatial variation in bacterial diversity and community structure was observed for the investigated mangrove soils. Heavy metal pollution played a key role in reducing the bacterial diversity. The spatial variation in soil-borne heavy metals shaped the spatial variation in bacterial diversity and community structure in the study area. Other environmental factors such as total carbon and total nitrogen in the soils that are affected by seasonal change in temperature could also influence the bacterial abundance, diversity and community structure though the temporal variation was relatively weaker, as compared to spatial variation. The bacterial diversity index was lower in the investigated site than in the comparable reference site with less contaminated status. The community structure in mangrove soils at the current study site was, to a remarkable extent, different from those in the tropical mangrove wetlands around the world.

scholarly journals Spatial distribution and temporal variation of microcrustaceans assembly (Cladocera and Copepoda) in different compartments of a reservoir in the brazilian semiarid region

2018 ◽  
Vol 30 (0) ◽  
Author(s):  
Josiane Souza Santos ◽  
Nadson Ressyé Simões ◽  
Sérgio Luiz Sonoda
Keyword(s):  
Spatial Distribution ◽  
Spatial Variation ◽  
Temporal Variation ◽  
Aquatic Macrophytes ◽  
Temporal Dynamics ◽  
Lateral Compartment ◽  
Spatial And Temporal Variation ◽  
Semiarid Region ◽  
Brazilian Semiarid ◽  
Significant Spatial Variation

Abstract Aim: The objective of this study was to investigate the spatial and temporal variation of microcrustacean assemblages of a reservoir in the Brazilian semiarid region. Methods Physical and chemical water variables and samples of microcrustaceans were collected at eight sites of the reservoir between July 2013 and November 2014, in a total of seven campaigns. For this study, the reservoir was categorized in two compartments: lateral and central. Results Limnological variables showed significant temporal variation (PERMANOVA, Pseudo-F = 19.51, p = 0.001). Higher turbidity values and suspended solids were observed in the rainiest months, while during the dry months, we measured higher values of transparency, dissolved oxygen, and chlorophyll-a. It was not found significant spatial variation of limnological variables (PERMANOVA, Pseudo-F = 0.96; p = 0.394). During the study period, ten species were recorded: four Cladocera (Ceriodaphnia cornuta, Daphnia gessneri, Diaphanosoma birgei and Diaphanosoma spinulosum ) three Copepoda Calanoida (Argyrodiaptomus azevedoi, Notodiaptomus cearensis and Notodiaptomus iheringi) and three Copepoda Cyclopoida (Macrocyclops albidus, Thermocyclops minutus and Thermocyclops decipiens). The microcrustacean assemblages showed significant temporal variation (PERMANOVA, Pseudo-F = 4.34; p = 0.001) as well as significant spatial variation (PERMANOVA, Pseudo-F = 9.46; p = 0.001). The highest values of abundance and richness were observed in the lateral compartment, this result is mainly related to the presence of aquatic macrophytes in this region, because the analysis of partial RDA indicated that limnological variables explained only 11% of this variation (Pseudo-F = 2.08, p = 0.001). Conclusions The results suggest that the seasonality of the semiarid is an important factor in the temporal dynamics of the limnological variables, while the aquatic macrophytes play an important role in the spatial distribution of the microcrustacean assembly.

Spatial variation in CO2 efflux from the soil in a mature beech forest ecosystem.

2021 ◽  
Author(s):  
Yihan Cai ◽  
Takahiro Nishimura ◽  
Hideyuki Ida ◽  
Mitsuru Hirota
Keyword(s):  
Spatial Variation ◽  
Temporal Variation ◽  
Forest Ecosystem ◽  
Linear Regression Analysis ◽  
Basal Area ◽  
Beech Forest ◽  
Controlling Factors ◽  
Spatial And Temporal Variation ◽  
Canopy Openness ◽  
Co2 Efflux

<p> Soil respiration (Rs) is the second largest carbon flux between the atmosphere and terrestrial ecosystem. Because of the large proportion, even small change in Rs would considerably impact the global carbon cycle. Therefore, it is important to accurately estimate Rs by taking its spatial and temporal variation into consideration. While the temporal variation of Rs and its controlling factors have been well-described, large unexplainable part still has been remained in the spatial variation of Rs especially in the forest ecosystems with complex structures. The objective of this study is to fill the knowledge gap about spatial variation of Rs and its controlling factors in a typical mature beech forest in Japan. Hypotheses of this study were, 1) Rs would show large spatial variation in the mature beech forest, 2) the spatial variation of Rs was mainly influenced by soil water content (SWC) and soil temperature (ST), 3) the two key factors were determined by the forest structures. This study was conducted in a 1- ha permanent study plot in the mature beech forest with significant gap-mosaic structures. To examine these hypotheses, Rs, SWC, ST and parameters related to forest structure, i.e. sum of basal area, diameter at breast height, number of trees, number of species within a radius of 5 m from the Rs measurement points, and canopy openness were measured at 121 points in different season between 2012 to 2013. In this study, all the measurements of Rs were conducted by using alkali-absorption technique.</p><p> Coefficient of variation of Rs was between 25 - 28 % which was similar to that of SWC in all the measurements. The spatial variation of Rs was relatively higher in July, August and September than that in June and October. There was no significant relationship in the spatial variation between Rs and ST in all the measurements, meanwhile, Rs was well explained by SWC in measurements conducted in August, September and October. Multiple linear regression analysis indicated that canopy openness and sum of basal area showed significant positive and negative correlation with SWC, respectively. And canopy openness explained SWC much more than sum of basal area did. This result suggested that SWC, the key factor determined the spatial variation of Rs, cannot be only explained by stems distribution and their characteristics, but also canopy architecture in the forest ecosystem.</p>

scholarly journals Temporal and spatial variation of limnological variables and biomass of different macrophyte species in a Neotropical reservoir (São Paulo - Brazil)

2013 ◽  
Vol 25 (4) ◽  
pp. 387-397 ◽  
Author(s):  
Flávia Bottino ◽  
Maria do Carmo Calijuri ◽  
Kevin Joseph Murphy
Keyword(s):  
Spatial Variation ◽  
Temporal Variation ◽  
Environmental Variables ◽  
Plant Distribution ◽  
Pistia Stratiotes ◽  
Spatial And Temporal Variation ◽  
Trophic State Index ◽  
Water And Sediment ◽  
Inorganic Substances ◽  
Eichhornia Azurea

AIM: This study reports an investigation of limnological characteristics and aquatic macrophyte occurrence in a neotropical reservoir in order to assess the spatio-temporal variation of water and sediment variables and their influence on plant distribution. METHODS: Macrophytes, water and sediment samples were collected from a Brazilian reservoir in different seasons from four main arms of the reservoir. In total sixteen water-sediment variables were analyzed including N:P ratio and Trophic State Index. The plants were collected using a quadrat sampling procedure and the dry weight per sample was measured. MANOVA was performed to evaluate spatial and temporal variation of environmental variables as well as seasonal biomass differences. To assess the relationship among environmental variables and macrophytes an ordination analysis (using Canonical Correspondence Analysis: CCA) was carried out. RESULTS: The spatial and temporal variation of limnological variables generated a heterogeneous system which supports the presence of different species of macrophyte. pH, dissolved oxygen and sediment composition were important predictors of Polygonum lapathifolium occurrence while nutrients were associated with Eichhornia crassipes and Pistia stratiotes. Inorganic substances were related to biomass variation of Eichhornia azurea and Myriophyllum aquaticum. CONCLUSIONS: The spatial variation of the environmental variables has caused heterogeneity in the reservoir and it may support the occurrence of different species of macrophyte. Limnological variables highlighted in CCA are important to predict the species occurrence and their control in the study area.

scholarly journals The Gut Microbiome and Diabetes Status in the Multiethnic Cohort

2020 ◽  
Vol 4 (Supplement_2) ◽  
pp. 1450-1450
Author(s):  
Gertraud Maskarinec ◽  
Phyllis Raquinio ◽  
Bruce Kristal ◽  
Lynne Wilkens ◽  
Adrian Franke ◽  
...  
Keyword(s):  
Community Structure ◽  
Gut Microbiome ◽  
Diversity Index ◽  
16S Rrna Gene Sequencing ◽  
Sensu Stricto ◽  
Rrna Gene ◽  
Gram Negative ◽  
Bonferroni Adjustment ◽  
Multiethnic Cohort ◽  
Diabetes Status

Abstract Objectives As features of the gut microbiome may promote the development of type 2 diabetes (T2D), we examined the hypothesis that gut microbiome composition differs by glycemic/diabetes status within a subset of the Multiethnic Cohort. We also estimated the association of lipopolysaccharide-binding protein (LBP) as a measure of circulating bacterial endotoxin with T2D. This outer membrane component of gram-negative bacteria may affect glucose metabolism. Methods In 2013–16, cohort members from 5 ethnic groups completed clinic visits, questionnaires, and stool collections. Participants with self-reported T2D and/or taking medication were considered T2D cases. Those with fasting glucose >125 and 100–125 mg/dL were classified as undiagnosed (UT2D) and prediabetes (PT2D). We characterized the gut microbiome through 16S rRNA gene sequencing (V1-V3). Plasma LBP was measured by ELISA. Linear regression was applied to estimate associations of gut microbiome community structure and LBP with T2D status adjusting for relevant confounders. Results Among 1756 participants (59.9–77.4 years), 315 (18%) were T2D, 158 (9%) UT2D, 518 (29%) PT2D, and 765 (44%) normoglycemic (NG). The Shannon diversity index was lower (6.30, 6.25, 6.28, 6.18; P = 0.02) and LBP was higher (26.0, 26.6, 28.6, 28.2 µg/mL; P = 0.0009) in T2D than NG participants. Of 10 phyla, Actinobacteria and Firmicutes were inversely associated with T2D status (P = 0.004). Six of 161 genera were significantly related to T2D status after Bonferroni adjustment: the abundance of Clostridium sensu stricto 1, Lachnospira, Lachnospiraceae NC2004, and Peptostreptococcaceae was lower, while Lachnospiraceae uncultured and Escherichia-Shigella were more abundant among T2D than NG participants. In general, those with PT2D and UT2D had values closer to NG than T2D individuals. Conclusions Participants with T2D showed a lower abundance of bacteria capable of fermenting plant polysaccharides and higher levels of gram-negative endotoxin-producing bacteria indicating that a less favorable pattern of gut microbiome community structure may contribute to T2D through endotoxin binding to toll-like receptors via LBP and activation of the NFkB pathway associated with chronic systemic inflammation. Funding Sources NIH grants P01CA169530, U01CA164973, P30CA071789, #UL1TR000130, R01HL140335.

scholarly journals Bacterial diversity and community structure in nitrate-contaminated shallow groundwater in the Poyang Lake basin, China

2019 ◽  
Vol 98 ◽  
pp. 01012 ◽  
Author(s):  
Yihui Dong ◽  
Jiale Li ◽  
Zhanxue Sun ◽  
Evgeniya Soldatova ◽  
Jinjing Zan
Keyword(s):  
Community Structure ◽  
Bacterial Diversity ◽  
Poyang Lake ◽  
Shallow Groundwater ◽  
Jiangxi Province ◽  
Lake Basin ◽  
Rrna Gene ◽  
Bacterial Populations ◽  
Poyang Lake Basin ◽  
Groundwater Environment

The Poyang Lake basin in the Jiangxi province of China has been exposed to nitrate pollution caused by irrigation practices, leading to high groundwater nitrate concentration. Eight groundwater samples were collected from shallow wells for hydrochemical, bacterial diversity, and community structure analysis in November 2017. Shallow groundwaters of the basin are weakly acid and in an oxidizing state, with EC ranging from 87.6 to 279.5 µS/cm and TDS varying between 53 to 344 mg/L and averaging of 164 mg/L. The NO3-N form is the dominant nitrogen species in groundwater, with сoncentrations of NO3-N, NO2-N and NH4-N ranging between 2.5 to 164 mg/L, 0.01 to 0.10 mg/L, <0.01 to 0.08 mg/L, respectively. Groundwater communities are dominated by actinobacteria, alphaproteobacterial, gammaproteobacteria and betaproteobacteria both in high- and low-nitrate groundwaters. The results of a 16S rRNA gene clone library indicate that the bacterial community structure of the high-nitrate groundwater is different from that of the low-nitrate groundwater. The bacterial populations Denitratisoma and Sulfuritalea detected in low-nitrate groundwater suggest that these bacteria are capable of denitrification in anaerobic groundwater environment. Bacterial populations Flavobacteria and Cytophagia in high-nitrate groundwater are common in the s wetlands examined and likely capable of nitrification.

scholarly journals Spatial and Temporal Variation in Enterococcal Abundance and Its Relationship to the Microbial Community in Hawaii Beach Sand and Water

2013 ◽  
Vol 79 (12) ◽  
pp. 3601-3609 ◽  
Author(s):  
Henglin Cui ◽  
Kun Yang ◽  
Eulyn Pagaling ◽  
Tao Yan
Keyword(s):  
Microbial Community ◽  
Temporal Variation ◽  
Beach Sand ◽  
Spatial And Temporal Variation ◽  
Rrna Gene ◽  
Fecal Indicator ◽  
Bacterial Populations ◽  
Mass Unit ◽  
Content Type ◽  
Beach Water

ABSTRACTRecent studies have reported high levels of fecal indicator enterococci in marine beach sand. This study aimed to determine the spatial and temporal variation of enterococcal abundance and to evaluate its relationships with microbial community parameters in Hawaii beach sand and water. Sampling at 23 beaches on the Island of Oahu detected higher levels of enterococci in beach foreshore sand than in beach water on a mass unit basis. Subsequent 8-week consecutive samplings at two selected beaches (Waialae and Kualoa) consistently detected significantly higher levels of enterococci in backshore sand than in foreshore/nearshore sand and beach water. Comparison between the abundance of enterococci and the microbial communities showed that enterococci correlated significantly with totalVibrioin all beach zones but less significantly with total bacterial density andEscherichia coli. Samples from the different zones of Waialae beach were sequenced by 16S rRNA gene pyrosequencing to determine the microbial community structure and diversity. The backshore sand had a significantly more diverse community and contained different major bacterial populations than the other beach zones, which corresponded to the spatial distribution pattern of enterococcal abundance. Taken together, multiple lines of evidence support the possibility of enterococci as autochthonous members of the microbial community in Hawaii beach sand.

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