scholarly journals Shifts in Rhizoplane Communities of Aquatic Plants after Cadmium Exposure

2005 ◽  
Vol 71 (5) ◽  
pp. 2484-2492 ◽  
Author(s):  
Lisa M. Stout ◽  
Klaus Nüsslein
Keyword(s):  
Bacterial Communities ◽  
Aquatic Plant ◽  
Lemna Minor ◽  
Diversity Index ◽  
Diversity Indices ◽  
Laboratory Culture ◽  
Contaminated Site ◽  
Community Studies ◽  
Plant Type ◽  
Dominant Group

ABSTRACT In this study we present the comparative molecular analysis of bacterial communities of the aquatic plant Lemna minor from a contaminated site (RCP) and from a laboratory culture (EPA), as well as each of these with the addition of cadmium. Plants were identified as L. minor by analysis of the rpl16 chloroplast region. Comparative bacterial community studies were based on the analyses of 16S rRNA clone libraries, each containing about 100 clones from the root surfaces of plants. Bacterial communities were compared at three phylogenetic levels of resolution. At the level of bacterial divisions, differences in diversity index scores between treatments, with and without cadmium within the same plant type (EPA or RCP), were small, indicating that cadmium had little effect. When we compared genera within the most dominant group, the β-proteobacteria, differences between unamended and cadmium-amended libraries were much larger. Bacterial diversity increased upon cadmium addition for both EPA and RCP libraries. Analyses of diversity at the phylotype level showed parallel shifts to more even communities upon cadmium addition; that is, percentage changes in diversity indices due to cadmium addition were the same for either plant type, indicating that contamination history might be independent of disturbance-induced diversity shifts. At finer phylogenetic levels of resolution, the effects of cadmium addition on bacterial communities were very noticeable. This study is a first step in understanding the role of aquatic plant-associated microbial communities in phytoremediation of heavy metals.

scholarly journals Effects of ship-breaking activities on the abundance and diversity of macrobenthos in Sitakundu Coast, Bangladesh

2020 ◽  
Vol 21 (11) ◽  
Author(s):  
Mohammad Belal Hossain ◽  
MD. ABU NOMAN ◽  
JAHANARA AKHTER LIPI ◽  
ABU HENA MUSTAFA KAMAL ◽  
MOHD HANAFI IDRIS
Keyword(s):  
Diversity Index ◽  
Anthropogenic Impacts ◽  
Benthic Communities ◽  
Diversity Indices ◽  
Dominant Group ◽  
Ecological Processes ◽  
Pollution Indicator ◽  
Ship Breaking ◽  
Distinct Grouping ◽  
Abundance And Diversity

Abstract. Lipi JA, Noman MDA, Hossain MB, Abu Hena MK, Idris MH. 2020. Effects of ship-breaking activities on the abundance and diversity of macrobenthos in Sitakundu Coast, Bangladesh. Biodiversitas 21: 5085-5093. To articulate the ecological processes or anthropogenic impacts, it is necessary to explore various distributional patterns of benthic communities. The study was conducted to investigate the variability of macrobenthos between a ship braking and non-ship-breaking area along the Sitakunda coast, Chittagong, Bangladesh. This is the first comprehensive study that addresses the effects of ship-breaking activities on the variability of benthic communities in the study area. Macrobenthos were sampled from two different regions namely Bhatiary (ship-breaking area) and Banshbaria (non-ship-breaking area/reference area) in two different time periods (April and July) for comparative analyses. During the study period, Polychaeta was the most dominant group comprising 60% of the total macrobenthos all over the study area. Macrobenthos abundance and diversity demonstrated strong spatial variability. The mean abundance varied from 3799.75±3452.28 ind./m2 to 4107.25±2743.6 ind./m2 from the ship-breaking to non-ship-breaking area. Similar to macrobenthos abundance, the diversity index (H′) (varied between 2.45 and 1.85), species richness (D) (varied between 1.99 and 1.04), and the number of taxa (varied between 17.25 and 9.25) were higher in the non-ship-breaking area compared to the ship-breaking area. Multivariate analyses, nMDS, and CCA plot showed a distinct grouping for different location. Besides, the diversity indices of the Polychaeta community, and the presence or absence of several pollution indicator taxa revealed that Bhatiary (the ship-breaking area) was confronting deleterious effects of ship-breaking activities.

Phytoplankton population as alarming warning bioindicator of water pollution in El-Temsah Lake, Egypt

2021 ◽  
Author(s):  
Mostafa Elshobary ◽  
Abdullah M. Attiah ◽  
Zenhom E. Salem ◽  
Dorya I. Essa
Keyword(s):  
Diversity Index ◽  
Nutrient Content ◽  
Organic Pollution ◽  
Abundant Species ◽  
Diversity Indices ◽  
Dominant Group ◽  
Annual Average ◽  
Sampling Locations ◽  
Polluted Sites ◽  
High Level

Abstract Relative effects of spatio-seasonal variations on the quantitative and qualitative status of phytoplankton in 20 sampling locations of Temsah Lake were examined during winter and summer 2018. The study reveals that the population structure consisted of 105 species from 69 genera, with an annual average of 924155 cell/L. Bacillariophyceae formed the most dominant group with 42.45% of total phytoplankton with an average of 372379 cell/L. Navicula creptocephala was the most abundant species representing 19.16% of total diatoms and 7.78% of the whole standing crop with an annual average of 376879 cell/L. The highest phytoplankton abundance was in the Northern locations. Phytoplankton density showed a negative correlation of pH, temperature and TDS and positively correlated with nutrient content such as nitrate and silicate. In general, summer showed high indices value compared to winter and the diversity index in the current study ranged in moderate pollution range. The polluted state of the aquatic ecosystem in El-Temsah Lake during summer is comparatively higher than winter during the study period. Palmer’s and diversity indices showed that Northern sites were the most flourishing and polluted sites. The study also recorded a number of tolerate algae (13 genera and 8 species), which can be used as an indicator for different degrees of organic pollution. Genus and species Palmer’s Index scores of the northern site were in the range of ≥20 during summer, indicating most of the sampling locations showed probable to confirmed high level of organic pollution.

scholarly journals Ecological investigation of Urpad beel: A major wetland of Goalpara district of Assam, India.

2018 ◽  
Vol 7 (4) ◽  
pp. 2112
Author(s):  
Upen Deka ◽  
Tapan Dutta
Keyword(s):  
Plant Community ◽  
Eichhornia Crassipes ◽  
Aquatic Macrophytes ◽  
Aquatic Plant ◽  
Ecological Study ◽  
Prime Factor ◽  
Diversity Index ◽  
Anthropogenic Activities ◽  
Diversity Indices ◽  
Life Forms

The present investigation deals with the ecological study of Urbad beel of Goalpara district of Assam with reference to aquatic plant community. The study was carried out during the year 2016 to 2017. Diversity indices viz. Shannon-Weiner diversity index, Simpson diversity index, Menhinick diversity index and Concentration of dominance were calculated to show the plant community structure of the wetland. A total of 93 aquatic macrophytic plant species belonging to 74 genera and 45 families have been reported from the wetland. Based on IVI value, Eichhornia crassipes was the most dominant species (IVI= 22.54) followed by Hygroryza aristata (IVI= 19.96), Arundo donax (IVI= 8.21) respectively whereas Cyperus brevifolius (IVI= 0.768) showed the lowest IVI value among all the life forms of the aquatic macrophytes of the wetland. Results showed that anthropogenic disturbances inside the wetland areas are the prime factor for losing aquatic plant community of the wetland. The obtained Shannon -diversity index values (3.06 and 2.18) both in summer and winter seasons indicate the further degradation of the wetland. Therefore, anthropogenic activities inside the wetland areas should be prevented for the sustainable existence of the wetland as well as the livelihood of the fringe villagers.

Carabidae of Barnaul city parks: ecological characteristics and species composition

2018 ◽  
Vol 8 (2) ◽  
pp. 348-353
Author(s):  
E. A. Kuchina ◽  
N. D. Ovcharenko ◽  
L. D. Vasileva
Keyword(s):  
Species Composition ◽  
Diversity Index ◽  
Similarity Index ◽  
Life Forms ◽  
Ground Beetles ◽  
Forest Steppe ◽  
Ecological Groups ◽  
Dominant Group ◽  
Species Diversity Index ◽  
Steppe Species

<p>Anthropogenic impact on the population of ground beetles leads to a change in their numbers, structure of dominance, density, species composition, spectrum of life forms. This makes the beetles Carabidae a convenient and informative bioindicator of the ecological state of biocenoses. The material for this work was the Carabidae collections conducted in June-August 2016-2017 in the park zone of different regions of Barnaul, differing in location, area, hydrological regime, vegetation cover, purpose and anthropogenic load. When processing the material, the quantitative, species and generic composition of the carabidae was determined, calculations were made for such indicators as the Berger-Parker dominance index, the Shannon species diversity index (Hs), and the Jacquard species similarity index. The fauna (Coleoptera, Carabidae) of the park zone of Barnaul is represented by 55 species belonging to 20 genera. The dominant group is represented by species belonging to steppe, forest and polyzonal groups. Forest-steppe species of ground beetles as dominants have not been identified in any of the investigated territories. The greatest variety of ecological groups was noted on the territory of the Yubileyny рark, which is explained by the presence of zones with various microclimatic conditions, the presence of a birch grove that flows through the park with the Pivovarka River, and a wide log in the park. Registered species belong to eight groups of life forms belonging to two classes - zoophagous and myxophytophagous. On the numerical and species abundance, zoophages predominate. The spectrum of life forms corresponds to the zonal spectrum characteristic of the forest-steppe zone.</p><p> </p>

scholarly journals On a Variational Definition for the Jensen-Shannon Symmetrization of Distances Based on the Information Radius

Entropy ◽  
2021 ◽  
Vol 23 (4) ◽  
pp. 464
Author(s):  
Frank Nielsen
Keyword(s):  
Diversity Index ◽  
Diversity Indices ◽  
Shannon Diversity Index ◽  
Probability Measures ◽  
Variational Optimization ◽  
Shannon Diversity ◽  
Concept Of Information ◽  
Jensen Shannon Divergence

We generalize the Jensen-Shannon divergence and the Jensen-Shannon diversity index by considering a variational definition with respect to a generic mean, thereby extending the notion of Sibson’s information radius. The variational definition applies to any arbitrary distance and yields a new way to define a Jensen-Shannon symmetrization of distances. When the variational optimization is further constrained to belong to prescribed families of probability measures, we get relative Jensen-Shannon divergences and their equivalent Jensen-Shannon symmetrizations of distances that generalize the concept of information projections. Finally, we touch upon applications of these variational Jensen-Shannon divergences and diversity indices to clustering and quantization tasks of probability measures, including statistical mixtures.

scholarly journals Effects of Plastic Debris on the Biofilm Bacterial Communities in Lake Water

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1465
Author(s):  
Chao Shen ◽  
Liuyan Huang ◽  
Guangwu Xie ◽  
Yulai Wang ◽  
Zongkai Ma ◽  
...  
Keyword(s):  
Community Structure ◽  
Bacterial Community ◽  
Bacterial Communities ◽  
Bacterial Community Structure ◽  
Diversity Index ◽  
Plastic Substrate ◽  
Simpson Index ◽  
Plastic Debris ◽  
Plastic Substrates ◽  
Wiener Diversity Index

Increasing discharge of plastic debris into aquatic ecosystems and the worsening ecological risks have received growing attention. Once released, plastic debris could serve as a new substrate for microbes in waters. The complex relationship between plastics and biofilms has aroused great interest. To confirm the hypothesis that the presence of plastic in water affects the composition of biofilm in natural state, in situ biofilm culture experiments were conducted in a lake for 40 days. The diversity of biofilm attached on natural (cobble stones (CS) and wood) and plastic substrates (Polyethylene terephthalate (PET) and Polymethyl methacrylate (PMMA)) were compared, and the community structure and composition were also analyzed. Results from high-throughput sequencing of 16S rRNA showed that the diversity and species richness of biofilm bacterial communities on natural substrate (observed species of 1353~1945, Simpson index of 0.977~0.989 and Shannon–Wiener diversity index of 7.42~8.60) were much higher than those on plastic substrates (observed species of 900~1146, Simpson index of 0.914~0.975 and Shannon–Wiener diversity index of 5.47~6.99). The NMDS analyses were used to confirm the taxonomic significance between different samples, and Anosim (p = 0.001, R = 0.892) and Adonis (p = 0.001, R = 808, F = 11.19) demonstrated that this classification was statistically rigorous. Different dominant bacterial communities were found on plastic and natural substrates. Alphaproteobacterial, Betaproteobacteria and Synechococcophycideae dominated on the plastic substrate, while Gammaproteobacteria, Phycisphaerae and Planctomycetia played the main role on the natural substrates. The bacterial community structure of the two substrates also showed significant difference which is consistent with previous studies using other polymer types. Our results shed light on the fact that plastic debris can serve as a new habitat for biofilm colonization, unlike natural substrates, pathogens and plastic-degrading microorganisms selectively attached to plastic substrates, which affected the bacterial community structure and composition in aquatic environment. This study provided a new insight into understanding the potential impacts of plastics serving as a new habitat for microbial communities in freshwater environments. Future research should focus on the potential impacts of plastic-attached biofilms in various aquatic environments and the whole life cycle of plastics (i.e., from plastic fragments to microplastics) and also microbial flock characteristics using microbial plastics in the natural environment should also be addressed.

The rhizosphere of an aquatic plant (Lemna minor)

1969 ◽  
Vol 15 (8) ◽  
pp. 964-966 ◽  
Author(s):  
R. A. Coler ◽  
H. B. Gunner
Keyword(s):  
Population Density ◽  
Carrying Capacity ◽  
Aquatic Plant ◽  
Lemna Minor ◽  
Fold Increase ◽  
Inert Surfaces

Dominant epiphytes colonizing the surface of Lemna minor were identified and enumerated. The distribution of these organisms compared to populations on inert surfaces at depths 0, [Formula: see text], 1, 2, 4 and 8 in. revealed greater than a 100-fold increase in population density. This enhanced carrying capacity of the plant diminished with depth.

scholarly journals Distance Effects on Diversity and Abundance of the Flower Visitors of Ocimum kilimandscharicum in the Kakamega Forest Ecosystem

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Hellen K. Mandela ◽  
Mugatsia H. Tsingalia ◽  
Mary Gikungu ◽  
Wilbur M. Lwande
Keyword(s):  
Species Diversity ◽  
Diversity Index ◽  
Land Use Changes ◽  
Species Abundance ◽  
Diversity Indices ◽  
Forest Edge ◽  
Flower Visitors ◽  
Kakamega Forest ◽  
Species Invasions ◽  
Wiener Diversity Index

Pollination is an important ecosystem service in the maintenance of biodiversity and most importantly in food production. Pollination is on the decline due to habitat loss, exotic species invasions, pollution, overharvesting, and land use changes. This study analyzed the abundance and diversity of flower visitors’ of Ocimum kilimandscharicum in Kakamega forest with increasing distance from the forest edge. Data were collected through direct observation and sweep netting. Six study sites were identified along two transects each 2.5 km long and labeled A to F. Distance in metres from the forest edge to each site was A=221, B=72, C=83, D=198, E=113, and F=50. Sampling was done from 7:30 am to 4:00 pm, three days in a week for five months consecutively. Diversity indices of different flower visitors were calculated using the Shannon-Wiener diversity index. One-way analysis of variance was used to compare differences between sites and a two-sample t-test was used to identify mean significant differences in species diversity between the closest and the furthest sites. A total of 645 individuals belonging to 35 species were captured from 4 families. The highest diversity was at site F (H’= 2.38) which was closest to the forest edge and the lowest diversity was from site A (H’=1.44) which was furthest from the forest edge. Distance from the forest edge significantly influenced species diversity (F(3, 20)=14.67, p=0.024). Distance from the forest edge also significantly influenced species abundance between the furthest sites A, D, and E and the nearest sites F, B, and C to the forest edge (t=4.177; p=0.0312) and species richness (t=3.2893; p=0.0187). This study clearly demonstrates that Ocimum kilimandscharicum flower visitors play essential roles in pollination and their higher number of visits translates into higher numbers of seeds set. Many of these pollinators are associated with the forest and hence the need to conserve the Kakamega forest as a source pool for pollinators.

scholarly journals Do soil bacterial communities respond differently to abrupt or gradual additions of copper?

2018 ◽  
Vol 95 (1) ◽  
Author(s):  
Michael McTee ◽  
Lorinda Bullington ◽  
Matthias C Rillig ◽  
Philip W Ramsey
Keyword(s):  
Heavy Metals ◽  
Soil Respiration ◽  
Microbial Communities ◽  
Bacterial Communities ◽  
Diversity Indices ◽  
Microbial Populations ◽  
Metal Concentrations ◽  
Soil Bacterial Communities ◽  
Bacterial Richness

ABSTRACTMany experiments that measure the response of microbial communities to heavy metals increase metal concentrations abruptly in the soil. However, it is unclear whether abrupt additions mimic the gradual and often long-term accumulation of these metals in the environment where microbial populations may adapt. In a greenhouse experiment that lasted 26 months, we tested whether bacterial communities and soil respiration differed between soils that received an abrupt or a gradual addition of copper or no copper at all. Bacterial richness and other diversity indices were consistently lower in the abrupt treatment compared to the ambient treatment that received no copper. The abrupt addition of copper yielded different initial bacterial communities than the gradual addition; however, these communities appeared to converge once copper concentrations were approximately equal. Soil respiration in the abrupt treatment was initially suppressed but recovered after four months. Afterwards, respiration in both the gradual and abrupt treatments wavered between being below or equal to the ambient treatment. Overall, our study indicates that gradual and abrupt additions of copper can yield similar bacterial communities and respiration, but these responses may drastically vary until copper concentrations are equal.

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