Acidogenic microbial species diversity in anaerobic digesters treating different substrates

1994 ◽  
Vol 30 (12) ◽  
pp. 55-61 ◽  
Author(s):  
T. J. Britz ◽  
G. Spangenberg ◽  
C. A. Venter
Keyword(s):  
Species Diversity ◽  
Landfill Leachate ◽  
Environmental Variables ◽  
Fixed Bed ◽  
Taxonomic Diversity ◽  
The Other ◽  
Process Efficiency ◽  
Anaerobic Digesters ◽  
Microbial Species ◽  
Taxonomic Methods

Microbial species diversity was determined for the acidogenic populations of four different digesters treating landfill leachate, a petrochemical effluent and sewage. The digesters were a downflow fixed-bed, conventional, cold conventional and an upflow hybrid design. The 288 strains isolated from the digesters were characterized using API test systems and identifications confirmed using current taxonomic methods. The taxonomic diversity was determined using the Shannon (H′) and equitability (J′) indices. The species from the four digesters were very similar with the exception of those from the digester treating the landfill leachate. The higher diversity in the latter was probably due to the diverse composition of the leachate, suggesting that members of this population were more generalists, as opposed to the more narrowly constrained members in the other three digesters. The data indicated that in a digester environment dominated by a more specific carbon containing effluent, like a petrochemical effluent, the population becomes stenotolerant and is characterized by a lower species diversity. Such a population would not be able to cope as well with environmental fluctuations. With a more diverse substrate like the landfill leachate, generalists, having a wider range for environmental variables, would dominate. This is important in terms of anaerobic digester process efficiency and stability.

scholarly journals Trichoptera diversity in Icelandic springs

Zoosymposia ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 46-52
Author(s):  
AGNES-KATHARINA KREILING ◽  
GÍSLI M. GÍSLASON ◽  
BJARNI K. KRISTJÁNSSON
Keyword(s):  
Species Diversity ◽  
Water Temperature ◽  
Environmental Variables ◽  
The Other ◽  
Larval Abundance ◽  
Sandy Substrate ◽  
Other Hand ◽  
Environmental Properties ◽  
Freshwater Springs

The aim of this study was to characterize the Trichoptera fauna of freshwater springs in Iceland and to relate distribution of caddis larvae to environmental properties of the springs. Out of a total of 48 springs sampled, Trichoptera larvae were found in only eleven. Larval densities were low, as was species diversity. Only three of the 12 species known to occur in Iceland were found: Apatania zonella, Limnephilus griseus, and Limnephilus affinis. The occurrence of A. zonella in springs in North-Iceland may suggest that springs might play a role as refugia for this species that is otherwise excluded from the area by larvae of the predatory caddis species Potamophylax cingulatus, which seems to be absent from spring habitats. Caddis larval abundance was higher in rheocrene springs and in springs with sandy substrate, and decreased with increasing water temperature. Presence or absence of Trichoptera larvae, on the other hand, was not associated with any of the environmental variables measured.

scholarly journals MÉTODOS QUANTITATIVOS PARA MENSURAR A DIVERSIDADE TAXONÔMICA EM PEIXES DE RIACHO

2021 ◽  
Vol 25 (02) ◽  
pp. 398-414
Author(s):  
Naraiana Loureiro Benone ◽  
◽  
Luciano Fogaça de Assis Montag ◽  
Keyword(s):  
Species Diversity ◽  
Beta Diversity ◽  
Environmental Variables ◽  
Large Scale ◽  
Taxonomic Diversity ◽  
Stream Fish ◽  
Diversity Patterns ◽  
The Relationship ◽  
Habitat Variables

Species diversity is defined as the variety of species and their relative abundances, and can be decomposed in local (alpha), regional (gamma) and between-communities (beta) diversity. For decades, studies with Brazilian stream fish focused on the relationship between local environmental variables and diversity patterns. However, dispersal gained notoriety for being important to the organization of communities. Besides, large scale variables are increasingly being perceived as good predictors of diversity, complementing the role of habitat variables. We present here a brief review of the methods to obtain alpha and beta taxonomic diversity, considerations regarding their predictors, and their main analysis.

Role of filter media in an anaerobic fixed-bed reactor

1995 ◽  
Vol 31 (9) ◽  
pp. 137-144 ◽  
Author(s):  
T. Miyahara ◽  
M. Takano ◽  
T. Noike
Keyword(s):  
Anaerobic Bacteria ◽  
Fixed Bed ◽  
Methanogenic Bacteria ◽  
The Other ◽  
Fixed Bed Reactor ◽  
Filter Media ◽  
Fixed Bed Reactors ◽  
Attached Bacteria ◽  
The Relationship

The relationship between the filter media and the behaviour of anaerobic bacteria was studied using anaerobic fixed-bed reactors. At an HRT of 48 hours, the number of suspended acidogenic bacteria was higher than those attached to the filter media. On the other hand, the number of attached methanogenic bacteria was more than ten times as higher than that of suspended ones. The numbers of suspended and deposited acidogenic and methanogenic bacteria in the reactor operated at an HRT of 3 hours were almost the same as those in the reactor operated at an HRT of 48 hours. Accumulation of attached bacteria was promoted by decreasing the HRT of the reactor. The number of acidogenic bacteria in the reactor packed sparsely with the filter media was higher than that in the closely packed reactor. The number of methanogenic bacteria in the sparsely packed reactor was lower than that in the closely packed reactor.

scholarly journals Phylogenetic paleoecology: macroecology within an evolutionary framework

Paleobiology ◽  
2021 ◽  
Vol 47 (2) ◽  
pp. 171-177
Author(s):  
James C. Lamsdell ◽  
Curtis R. Congreve
Keyword(s):  
Species Diversity ◽  
Spatial Variation ◽  
Geographic Distribution ◽  
Evolutionary Biology ◽  
Phylogenetic Signal ◽  
Evolutionary Rates ◽  
The Other ◽  
Ecological Data ◽  
Temporal And Spatial Variation ◽  
Temporal And Spatial

The burgeoning field of phylogenetic paleoecology (Lamsdell et al. 2017) represents a synthesis of the related but differently focused fields of macroecology (Brown 1995) and macroevolution (Stanley 1975). Through a combination of the data and methods of both disciplines, phylogenetic paleoecology leverages phylogenetic theory and quantitative paleoecology to explain the temporal and spatial variation in species diversity, distribution, and disparity. Phylogenetic paleoecology is ideally situated to elucidate many fundamental issues in evolutionary biology, including the generation of new phenotypes and occupation of previously unexploited environments; the nature of relationships among character change, ecology, and evolutionary rates; determinants of the geographic distribution of species and clades; and the underlying phylogenetic signal of ecological selectivity in extinctions and radiations. This is because phylogenetic paleoecology explicitly recognizes and incorporates the quasi-independent nature of evolutionary and ecological data as expressed in the dual biological hierarchies (Eldredge and Salthe 1984; Congreve et al. 2018; Fig. 1), incorporating both as covarying factors rather than focusing on one and treating the other as error within the dataset.

A molecular analysis reveals hidden species diversity within the current concept of Russula maculata (Russulaceae, Basidiomycota)

Phytotaxa ◽  
2016 ◽  
Vol 270 (2) ◽  
pp. 71 ◽  
Author(s):  
SLAVOMÍR ADAMČÍK ◽  
MIROSLAV CABOŇ ◽  
URSULA EBERHARDT ◽  
MALKA SABA ◽  
FELIX HAMPE ◽  
...  
Keyword(s):  
Species Diversity ◽  
Molecular Analysis ◽  
Morphological Characteristics ◽  
Its Region ◽  
The Other ◽  
Deciduous Forests ◽  
European Species ◽  
Spore Ornamentation ◽  
Sister Clade ◽  
Broad Concept

The current generally accepted concept of Russula maculata defines the species by yellow-brownish spots on the basidiomata, an acrid taste, a yellow spore print and a red pileus. This concept was tested using collections originating from various geographical areas mainly in Europe. Analyses of the ITS region suggested that there were three species within this broad concept. One of them, R. maculata, was identified based on the sequence from the epitype. Two other species, R. nympharum and R. sp., are described here as newly identified species. The European species R. maculata and R. nympharum grow in deciduous forests, are similar in their field aspect and are distinctly different in micro-morphological characteristics of spores, pleurocystidia and pileipellis. An Asian species, R. sp., is associated with pine and has smaller basidiomata and spores. These three species form the R. maculata complex and represent the sister clade to the R. globispora complex. This clade consists of species also characterized by a yellow-brownish context discolouration but with a different type of spore ornamentation. All of the other tested species had an acrid taste and yellow spore print but did not have a conspicuous yellow-brownish context discolouration and were placed in various unrelated clades.

Taxonomy and the Direct Historical Approach

1942 ◽  
Vol 8 (2) ◽  
pp. 170-172 ◽  
Author(s):  
W. C. McKern
Keyword(s):  
The Other ◽  
Historical Approach ◽  
Taxonomic Methods

It seems apparent from Julian Steward's latest statement on The Direct Historical Approach to Archaeology that he still conceives of a basic conflict, or at least an inherent competition, between the direct historical and midwestern taxonomic methods, in spite of his initial statement to the contrary. He manifests a conviction that the latter is being overemphasized at the expense of the former. If his fears are well founded (and there are instances of malpractice which might be cited in support of his position), I should be among the first to join his crusade in defense of the direct historical “approach.” However, in that case, his criticism should be directed against the culprits who are misusing methods rather than against any given method itself. Instead, Steward adopts the tone of one who sets out to compare the respective values of two conflicting methods, to the glorification of one and the general degradation of the other.

The Effects of Adverse Environmental Conditions on Workload

1975 ◽  
Vol 19 (3) ◽  
pp. 301-304
Author(s):  
Ann E. Martin
Keyword(s):  
Environmental Conditions ◽  
Environmental Variables ◽  
Secondary Task ◽  
The Other ◽  
Random Numbers ◽  
Performance Decrement ◽  
Experimental Conditions ◽  
Continuous Noise ◽  
Adverse Environmental Conditions ◽  
Intermittent Noise

The present study was conducted to investigate the effects of environmental conditions on visual workload. The environmental variables used were temperature, studied at levels of 45°F., WBGT, and 95°F., WBGT; and noise, studied at 83 dBA intermittent noise and 93 dBA continuous noise. Workload was defined as the amount of attention demanded from an operator as measured by performance decrement on a secondary task while performing a primary and secondary task simultaneously. The secondary task was reading random numbers, and the primary task was reading word lists. Significant differences (p<.05) were found between the control condition and all experimental conditions. The low temperature and high temperature-continuous noise conditions were significantly different from the other conditions. Noise and temperature were found to significantly increase workload (p<05).

scholarly journals SPECIES DIVERSITY, UTILIZATION AND CONSERVATION IN HOME GARDENS OF SOME RESIDENTIAL AREAS, COIMBATORE, INDIA.

2015 ◽  
Vol 2 (1) ◽  
pp. 71-80 ◽  
Author(s):  
Jamuna S ◽  
Subhasree R ◽  
Karthika K ◽  
Paulsamy S ◽  
Thenmozhi K
Keyword(s):  
Species Diversity ◽  
Plant Species ◽  
Ocimum Basilicum ◽  
Home Gardens ◽  
The Other ◽  
Home Garden ◽  
Residential Areas ◽  
Important Species ◽  
Celosia Cristata ◽  
Number Of Plant Species

The present study was aimed at documenting species composition, utilization and conservation of plant species growing in home gardens of 10 residential areas of Coimbatore city, India. Household interviews and home garden surveys revealed that all the 109 plant species included in 60 families included have someeconomic uses or with ornamental significance. Higher number of species was herbs followed by shrubs, trees, climbers, succulent herbs, vines and sub-shrubs. The families viz., Asteraceae, Apocynaceae and Acanthaceae contributed higher number of plant species than the other families to the home gardens. Thespecies namely, Celosia cristata, Chrysanthemum odoratum and Ocimum basilicum have registered 50% frequency among the home gardens sampled which indicates that these species have distributed and maintained in comparatively higher number of home gardens. The home garden species are mainly under thecategories of vegetables, fruits, ornamentals, economic important species and medicinal. These results further report revealed that homegardens satisfy various household needs like food, ornamentals, medicines, building material, religious and ceremonial uses.

Metacommunities

2019 ◽  
pp. 266-284
Author(s):  
Gary G. Mittelbach ◽  
Brian J. McGill
Keyword(s):  
Species Diversity ◽  
Species Interactions ◽  
Neutral Theory ◽  
Patch Dynamics ◽  
Species Traits ◽  
Local Communities ◽  
The Other ◽  
Species Sorting ◽  
Niche Differences ◽  
Dynamics Of Populations

Just as the dispersal of individuals may link the dynamics of populations in space, the dispersal of species among communities may link local communities into a metacommunity. Four different perspectives characterize how dispersal rates, environmental heterogeneity, and species traits interact to influence diversity in metacommunities. These perspectives are: patch dynamics, species sorting, mass effects, and the neutral perspective. The neutral perspective stands in stark contrast to the other three perspectives in that it assumes that niche differences between species are unimportant and that species are demographically identical in terms of their birth, death, and dispersal rates. Under the neutral perspective, species diversity is maintained by a balance between speciation, extinction, and dispersal. Although neutral theory is incompatible with realistic modes and rates of speciation, it has been enormously influential in focusing our attention on the linkages between species interactions on local scales, and evolutionary and biogeographic processes occurring on large scales.

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