scholarly journals Determining Rates of Change and Evaluating Group-Level Resiliency Differences in Hyporheic Microbial Communities in Response to Fluvial Heavy-Metal Deposition

2004 ◽  
Vol 70 (8) ◽  
pp. 4756-4765 ◽  
Author(s):  
Kevin P. Feris ◽  
Philip W. Ramsey ◽  
Matthias Rillig ◽  
Johnnie N. Moore ◽  
James E. Gannon ◽  
...  

ABSTRACT Prior field studies by our group have demonstrated a relationship between fluvial deposition of heavy metals and hyporheic-zone microbial community structure. Here, we determined the rates of change in hyporheic microbial communities in response to heavy-metal contamination and assessed group-level differences in resiliency in response to heavy metals. A controlled laboratory study was performed using 20 flowthrough river mesocosms and a repeated-measurement factorial design. A single hyporheic microbial community was exposed to five different levels of an environmentally relevant metal treatment (0, 4, 8, 16, and 30% sterilized contaminated sediments). Community-level responses were monitored at 1, 2, 4, 8, and 12 weeks via denaturing gradient gel electrophoresis and quantitative PCR using group-specific primer sets for indigenous populations most closely related to the α-, β-, and γ-proteobacteria. There was a consistent, strong curvilinear relationship between community composition and heavy-metal contamination (R 2 = 0.83; P < 0.001), which was evident after only 7 days of metal exposure (i.e., short-term response). The abundance of each phylogenetic group was negatively affected by the heavy-metal treatments; however, each group recovered from the metal treatments to a different extent and at a unique rate during the course of the experiment. The structure of hyporheic microbial communities responded rapidly and at contamination levels an order of magnitude lower than those shown to elicit a response in aquatic macroinvertebrate assemblages. These studies indicate that hyporheic microbial communities are a sensitive and useful indicator of heavy-metal contamination in streams.

2004 ◽  
Vol 70 (4) ◽  
pp. 2323-2331 ◽  
Author(s):  
Kevin P. Feris ◽  
Philip W. Ramsey ◽  
Chris Frazar ◽  
Matthias Rillig ◽  
Johnnie N. Moore ◽  
...  

ABSTRACT Heavy metals contaminate numerous freshwater streams and rivers worldwide. Previous work by this group demonstrated a relationship between the structure of hyporheic microbial communities and the fluvial deposition of heavy metals along a contamination gradient during the fall season. Seasonal variation has been documented in microbial communities in numerous terrestrial and aquatic environments, including the hyporheic zone. The current study was designed to assess whether relationships between hyporheic microbial community structure and heavy-metal contamination vary seasonally by monitoring community structure along a heavy-metal contamination gradient for more than a year. No relationship between total bacterial abundance and heavy metals was observed (R 2 = 0.02, P = 0.83). However, denaturing gradient gel electrophoresis pattern analysis indicated a strong and consistent linear relationship between the difference in microbial community composition (populations present) and the difference in the heavy metal content of hyporheic sediments throughout the year (R 2 = 0.58, P < 0.001). Correlations between heavy-metal contamination and the abundance of four specific phylogenetic groups (most closely related to the α, β, and γ-proteobacteria and cyanobacteria) were apparent only during the fall and early winter, when the majority of organic matter is deposited into regional streams. These seasonal data suggest that the abundance of susceptible populations responds to heavy metals primarily during seasons when the potential for growth is highest.


mBio ◽  
2016 ◽  
Vol 7 (2) ◽  
Author(s):  
Christopher L. Hemme ◽  
Stefan J. Green ◽  
Lavanya Rishishwar ◽  
Om Prakash ◽  
Angelica Pettenato ◽  
...  

ABSTRACT Unraveling the drivers controlling the response and adaptation of biological communities to environmental change, especially anthropogenic activities, is a central but poorly understood issue in ecology and evolution. Comparative genomics studies suggest that lateral gene transfer (LGT) is a major force driving microbial genome evolution, but its role in the evolution of microbial communities remains elusive. To delineate the importance of LGT in mediating the response of a groundwater microbial community to heavy metal contamination, representative Rhodanobacter reference genomes were sequenced and compared to shotgun metagenome sequences. 16S rRNA gene-based amplicon sequence analysis indicated that Rhodanobacter populations were highly abundant in contaminated wells with low pHs and high levels of nitrate and heavy metals but remained rare in the uncontaminated wells. Sequence comparisons revealed that multiple geochemically important genes, including genes encoding Fe 2+ /Pb 2+ permeases, most denitrification enzymes, and cytochrome c 553 , were native to Rhodanobacter and not subjected to LGT. In contrast, the Rhodanobacter pangenome contained a recombinational hot spot in which numerous metal resistance genes were subjected to LGT and/or duplication. In particular, Co 2+ /Zn 2+ /Cd 2+ efflux and mercuric resistance operon genes appeared to be highly mobile within Rhodanobacter populations. Evidence of multiple duplications of a mercuric resistance operon common to most Rhodanobacter strains was also observed. Collectively, our analyses indicated the importance of LGT during the evolution of groundwater microbial communities in response to heavy metal contamination, and a conceptual model was developed to display such adaptive evolutionary processes for explaining the extreme dominance of Rhodanobacter populations in the contaminated groundwater microbiome. IMPORTANCE Lateral gene transfer (LGT), along with positive selection and gene duplication, are the three main mechanisms that drive adaptive evolution of microbial genomes and communities, but their relative importance is unclear. Some recent studies suggested that LGT is a major adaptive mechanism for microbial populations in response to changing environments, and hence, it could also be critical in shaping microbial community structure. However, direct evidence of LGT and its rates in extant natural microbial communities in response to changing environments is still lacking. Our results presented in this study provide explicit evidence that LGT played a crucial role in driving the evolution of a groundwater microbial community in response to extreme heavy metal contamination. It appears that acquisition of genes critical for survival, growth, and reproduction via LGT is the most rapid and effective way to enable microorganisms and associated microbial communities to quickly adapt to abrupt harsh environmental stresses.


2003 ◽  
Vol 69 (9) ◽  
pp. 5563-5573 ◽  
Author(s):  
Kevin Feris ◽  
Philip Ramsey ◽  
Chris Frazar ◽  
Johnnie N. Moore ◽  
James E. Gannon ◽  
...  

ABSTRACT The hyporheic zone of a river is nonphotic, has steep chemical and redox gradients, and has a heterotrophic food web based on the consumption of organic carbon entrained from downwelling surface water or from upwelling groundwater. The microbial communities in the hyporheic zone are an important component of these heterotrophic food webs and perform essential functions in lotic ecosystems. Using a suite of methods (denaturing gradient gel electrophoresis, 16S rRNA phylogeny, phospholipid fatty acid analysis, direct microscopic enumeration, and quantitative PCR), we compared the microbial communities inhabiting the hyporheic zone of six different river sites that encompass a wide range of sediment metal loads resulting from large base-metal mining activity in the region. There was no correlation between sediment metal content and the total hyporheic microbial biomass present within each site. However, microbial community structure showed a significant linear relationship with the sediment metal loads. The abundances of four phylogenetic groups (groups I, II, III, and IV) most closely related to α-, β-, and γ-proteobacteria and the cyanobacteria, respectively, were determined. The sediment metal content gradient was positively correlated with group III abundance and negatively correlated with group II abundance. No correlation was apparent with regard to group I or IV abundance. This is the first documentation of a relationship between fluvially deposited heavy-metal contamination and hyporheic microbial community structure. The information presented here may be useful in predicting long-term effects of heavy-metal contamination in streams and provides a basis for further studies of metal effects on hyporheic microbial communities.


Author(s):  
Sangeetha Annam ◽  
Anshu Singla

Abstract: Soil is a major and important natural resource, which not only supports human life but also furnish commodities for ecological and economic growth. Ecological risk has posed a serious threat to the ecosystem by the degradation of soil. The high-stress level of heavy metals like chromium, copper, cadmium, etc. produce ecological risks which include: decrease in the fertility of the soil; reduction in crop yield & degradation of metabolism of living beings, and hence ecological health. The ecological risk associated, demands the assessment of heavy metal stress levels in soils. As the rate of stress level of heavy metals is exponentially increasing in recent times, it is apparent to assess or predict heavy metal contamination in soil. The assessment will help the concerned authorities to take corrective as well as preventive measures to enhance the ecological and hence economic growth. This study reviews the efficient assessment models to predict soil heavy metal contamination.


Author(s):  
Made Rahayu Kusumadewi ◽  
I Wayan Budiarsa Suyasa ◽  
I Ketut Berata

Tukad Badung River is one of the potential contamination of heavy metal sare very highin the city of Denpasar. Tilapia (Oreochromis mossambicus) isa commonspecies of fish found in the river and became the object of fishing by the public. The fish is usually consume das a food ingredient forever yangler. Fish can be used as bio-indicators of chemical contamination in the aquatic environment. Determination of heavy metal bioconcentration and analysis of liver histopathology gills organs and muscles is performed to determine the content of heavy metals Pb, Cd, and Cr+6, and the influence of heavy metal exposure to changes in organ histopathology Tilapia that live in Tukad Badung. In this observational study examined the levels of heavy metal contamination include Pb, Cd and Cr+6 in Tilapia meat with AAS method (Atomic Absorption Spectrofotometric), and observe the histopathological changes in organ preparations gills, liver, and muscle were stained with HE staining (hematoxylin eosin). Low Pb content of the fish that live in Tukad Badung 0.8385 mg/kg and high of 20.2600 mg/kg. The content of heavy metals Pb is above the quality standards specified in ISO 7378 : 2009 in the amount of 0.3 mg / kg. The content of Cr+6 low of 1.1402 mg / kg and the highest Cr+6 is 6.2214 mg / kg. The content of Cr+6 is above the quality standards established in the FAO Fish Circular 764 is equal to 1.0 mg / kg. In fish with Pb bioconcentration of 0.8385 mg / kg and Cr+6 of 1.1402 mg / kg was found that histopathological changes gill hyperplasia and fusion, the liver was found degeneration, necrosis, and fibrosis, and in muscle atrophy found. Histopathologicalchangessuch asedema and necrosis ofthe liveris foundin fishwith Pb bioconcentration of 4.5225mg/kg and Cr+6 amounted to2.5163mg/kg. Bio concentration of heavy metal contamination of lead (Pb) and hexavalent chromium (Cr+6) on Tilapia ( Oreochromis mossambicus ) who lives in Tukad Badung river waters exceed the applicable standard. Histopathological changes occur in organs gills, liver, and muscle as a result of exposure to heavy metals lead and hexavalent chromium. Advised the people not to eat Tilapia that live in Tukad Badung


Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3348
Author(s):  
Min Tan ◽  
Kun Wang ◽  
Zhou Xu ◽  
Hanghe Li ◽  
Junfeng Qu

Heavy metals accumulate in high water table coal mining subsidence ponds, resulting in heavy metal enrichment and destruction of the ecological environment. In this study, subsidence ponds with different resource reutilization methods were used as study subjects, and non-remediated subsidence ponds were collectively used as the control region to analyze the heavy metal distributions in water bodies, sediment, and vegetation. The results revealed the arsenic content in the water bodies slightly exceeded Class III of China’s Environmental Quality Standards for Surface Water. The lead content in water inlet vegetation of the control region and the Anguo wetland severely exceeded limits. Pearson’s correlation, PCA, and HCA analysis results indicated that the heavy metals at the study site could be divided into two categories: Category 1 is the most prevalent in aquaculture pond B and mainly originate from aquaculture. Category 2 predominates in control region D and mainly originates from atmospheric deposition, coal mining, and leaching. In general, the degree of heavy metal contamination in the Anguo wetland, aquaculture pond, and fishery–solar hybrid project regions is lower than that in the control region. Therefore, these models should be considered during resource reutilization of subsidence ponds based on the actual conditions.


Author(s):  
Diana FLORESCU ◽  
Andreea IORDACHE ◽  
Claudia SANDRU ◽  
Elena HORJ ◽  
Roxana IONETE ◽  
...  

As a result of accidental spills or leaks, industrial wastes may enter in soil and in streams. Some of the contaminants may not be completely removed by treatment processes; therefore, they could become a problem for these sources. The use of synthetic products (e.g. pesticides, paints, batteries, industrial waste, and land application of industrial or domestic sludge) can result in heavy metal contamination of soils.


2020 ◽  
Vol 18 (1) ◽  
pp. 99-116
Author(s):  
JR Xavier ◽  
V Mythri ◽  
R Nagaraj ◽  
VCP Ramakrishna ◽  
PE Patki ◽  
...  

Vegetables are defined as edible plant parts generally consumed raw or cooked with a main dish, in a mixed dish, as an appetizer or as a salad. Food safety aspects related to microbial quality (total plate count, yeast and mold and food borne pathogens) and toxic residue (heavy metals) and mineral content were investigated for vegetables such as green leafy vegetable, salad vegetables, sprouts, brinjal, green chilies and French beans collected from organic and conventional outlets from Mysore region, Karnataka, India. Microbial analysis was carried out using standard procedures and mminerals (Ca, K, Fe, Cu, Mg, Mn and Zn) and heavy metals (Cd and Pb) were determined. Significant variations (p>0.05) were observed for microbial quality among organic and conventional vegetables. Mineral and vitamin C content were also significantly higher (p>0.01) in organic samples. Heavy metal contamination for lead and cadmium tested positive for conventional samples while organic samples tested negative. The variables that contributed most for the variability were heavy metal contamination, mineral and vitamin C content. Organically grown vegetables were free from heavy metals and safe for consumption, as well as they are rich in mineral and vitamin C content in comparison to conventional samples. SAARC J. Agri., 18(1): 99-116 (2020)


2017 ◽  
Vol 3 (01) ◽  
pp. 25-31 ◽  
Author(s):  
Charu Gangwar ◽  
Aprajita Singh ◽  
Raina Pal ◽  
Atul Kumar ◽  
Saloni Sharma ◽  
...  

E-waste is a popular name given to those electronic products nearing the end of their useful life which has become a major source of heavy metal contamination in soil and hence, became the global concern. Various samples of soil were collected from different sites and were determined for heavy metal analysis by the ICP-AAS after the digestion process. The main source of contamination is illegal e-waste recycling activities such as burning of PCB's acid baths etc. Different soil indices like contamination factor, I-geo, pollution load index, were calculated to determine the quality of the soil. Results indicate that e-waste recycling and industrial area are strongly contaminated by the heavy metals. Physiological analysis of soil revealed that e-waste processing and industrial activities decrease the soil pH and organic matter while enhancing the electrical conductivity of soil. The exceedance of metal contamination imposed negative impact to the soil environment and human health.


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