scholarly journals Changes in Bacterioplankton Community Structure and Activity with Depth in a Eutrophic Lake as Revealed by 5S rRNA Analysis

2002 ◽  
Vol 68 (7) ◽  
pp. 3606-3613 ◽  
Author(s):  
Katja Dominik ◽  
Manfred G. Höfle
Keyword(s):  
Community Structure ◽  
Eutrophic Lake ◽  
5S Rrna ◽  
Bacterioplankton Community ◽  
Chemical Stratification ◽  
Different Seasons ◽  
Different Depths ◽  
Taxonomic Groups ◽  
Structure And Activity ◽  
Rrna Sequences

ABSTRACT The community structure of bacterioplankton was studied at different depths (0 to 25 m) of a temperate eutrophic lake (Lake Plußsee in northern Germany) by using comparative 5S rRNA analysis. The relative amounts of taxonomic groups were estimated from 5S rRNA bands separated by high-resolution electrophoresis. Comparison of partial 5S rRNA sequences enabled detection of changes in single taxa over space and during seasons. Overall, the bacterioplankton community was dominated by 3 to 14 abundant (>4% of the total 5S rRNA) taxa. In general, the number of 5S rRNA bands (i.e., the number of bacterial taxa) decreased with depth. In the fall, when thermal stratification and chemical stratification were much more pronounced than they were in the spring, the correlation between the depth layers and the community structure was more pronounced. Therefore, in the fall each layer had its own community structure; i.e., there were different community structures in the epilimnion, the metalimnion, and the hypolimnion. Only three 5S rRNA bands were detected in the hypolimnion during the fall, and one band accounted for about 70% of the total 5S rRNA. The sequences of individual 5S rRNA bands from the spring and fall were different for all size classes analyzed except two bands, one of which was identified as Comamonas acidivorans. In the overall analysis of the depth profiles, the diversity in the epilimnion contrasted with the reduced diversity of the bacterioplankton communities in the hypolimnion, and large differences occurred in the composition of the epilimnion at different seasons except for generalists like C. acidivorans.

scholarly journals Seasonal Dynamics of Bacterioplankton Community Structure in a Eutrophic Lake as Determined by 5S rRNA Analysis

1999 ◽  
Vol 65 (7) ◽  
pp. 3164-3174 ◽  
Author(s):  
Manfred G. Höfle ◽  
Heike Haas ◽  
Katja Dominik
Keyword(s):  
Community Structure ◽  
Seasonal Dynamics ◽  
Phytoplankton Bloom ◽  
Bacterial Species ◽  
Seasonal Succession ◽  
Eutrophic Lake ◽  
5S Rrna ◽  
Taxonomic Structure ◽  
Bacterioplankton Community ◽  
Taxonomic Groups

ABSTRACT Community structure of bacterioplankton was studied during the major growth season for phytoplankton (April to October) in the epilimnion of a temperate eutrophic lake (Lake Plußsee, northern Germany) by using comparative 5S rRNA analysis. Estimates of the relative abundances of single taxonomic groups were made on the basis of the amounts of single 5S rRNA bands obtained after high-resolution electrophoresis of RNA directly from the bacterioplankton. Full-sequence analysis of single environmental 5S rRNAs enabled the identification of single taxonomic groups of bacteria. Comparison of partial 5S rRNA sequences allowed the detection of changes of single taxa over time. Overall, the whole bacterioplankton community showed two to eight abundant (>4% of the total 5S rRNA) taxa. A distinctive seasonal succession was observed in the taxonomic structure of this pelagic community. A rather-stable community structure, with seven to eight different taxonomic units, was observed beginning in April during the spring phytoplankton bloom. A strong reduction in this diversity occurred at the beginning of the clear-water phase (early May), when only two to four abundant taxa were observed, with one taxon dominating (up to 72% of the total 5S rRNA). The community structure during summer stagnation (June and July) was characterized by frequent changes of different dominating taxa. During late summer, a dinoflagellate bloom (Ceratium hirudinella) occurred, with Comamonas acidovorans (β-subclass of the classProteobacteria) becoming the dominant bacterial species (average abundance of 43% of the total 5S rRNA). Finally, the seasonal dynamics of the community structure of bacterioplankton were compared with the abundances of other major groups of the aquatic food web, such as phyto- and zooplankton, revealing that strong grazing pressure by zooplankton can reduce microbial diversity substantially in pelagic environments.

Bacterioplankton community structure in a eutrophic lake in relation to water chemistry

2009 ◽  
Vol 25 (5) ◽  
pp. 763-772 ◽  
Author(s):  
Jin Zeng ◽  
Liuyan Yang ◽  
Hongwei Du ◽  
Lin Xiao ◽  
Lijuan Jiang ◽  
...  
Keyword(s):  
Community Structure ◽  
Water Chemistry ◽  
Eutrophic Lake ◽  
Bacterioplankton Community

scholarly journals Water quality and potamoplankton evaluation of the Nile River in Upper Egypt

2015 ◽  
Vol 27 (2) ◽  
pp. 171-190 ◽  
Author(s):  
Ahmed Mohamed El-Otify ◽  
Isaac Agaiby Iskaros
Keyword(s):  
Community Structure ◽  
Zooplankton Community ◽  
Water Level Fluctuations ◽  
Main Stream ◽  
Upper Egypt ◽  
Physical And Chemical Variables ◽  
Different Seasons ◽  
High Current Velocity ◽  
Major Nutrients ◽  
Physical And Chemical

Aim: The composition, abundance, community structure of potamoplankton and major physical and chemical variables of the Nile water in Upper Egypt were investigated to assess its status in different seasons during 2007.MethodsWater samples were collected seasonally during 2007 from six investigated sites from variable depths at levels of 0, 2.5 and 5 m. The area of this investigation is defined as the southern 120 Km of the main stream of the Nile in Upper Egypt (24° 04’ – 25° 00’ latitudes and 32° 51’ – 32° 54’ longitudes), downstream of Aswan Old Dam.ResultsAltogether, 121 potamoplankton species, of which 85 related to phytoplankton and 36 appertaining to zooplankton were recorded. Most numerous phytoplankton were Chlorophyceae (42 species) followed by Bacillariophyceae (30 species). Cyanobacteria and Dinophyceae were less numerous with only 11 and 2 species, respectively. Zooplankton species were mainly belonging to three systematic groups namely; Rotifera (24 species), Copepoda (3 species) and Cladocera (9 species). Besides, other rare zooplankton including Platyhelminthes, Nemata and Ciliophora were sparsely encountered. The main hydrological conditions characterizing the investigated area include water level fluctuations (˂82 - ˃85 m above sea level), relatively high current velocity (0.8 - 1.3 m sec–1) and disposal of wastewater. Plankton populations were variably but rather weakly dependent on the major nutrients due to their excessive availability in accessible form for uptake by the producers. For phytoplankton, the community structure was categorized in relation to temperature, pH, SO42– and Mg2+. For zooplankton, the community structure was categorized in relation to conductivity as well as Mg2+. Sampling intervals were inadequate to demonstrate the existing successional pattern of the Nile potamoplankton community. Alterations in the phytoplankton community structure accompanied changes in water temperature represented by the alternate dominance between diatoms and cyanobacteria, while zooplankton community was always dominated by rotifers. Phytoplankton populations were numerically more abundant in autumn and zooplankton peaked in spring.ConclusionsWastewater disposal restricted the abundance of the Nile zooplankton assemblages mainly due to the numerical decline of Rotifera and Cladocera. Otherwise, wastewater did not exert major limits for phytoplankton. The data obtained in this investigation will be crucial to understand potamoplankton regulation and contribute to the knowledge regarding the Limnology of the Nile basin.

scholarly journals Purine and pyrimidine composition in 5S rRNA and its mutational significance

1998 ◽  
Vol 21 (2) ◽  
pp. 255-258 ◽  
Author(s):  
Sandra Maria Rodrigues Subacius ◽  
Wilton de Oliveira Bussab
Keyword(s):  
Correlation Analysis ◽  
Chemical Nature ◽  
Point Mutations ◽  
Principal Component ◽  
Factorial Analysis ◽  
5S Rrna ◽  
Large Sample ◽  
Rrna Sequences

Variations observed in 5S rRNA base compositions are almost entirely due to fixation of point mutations. As a consequence, 5S rRNA size has remained relatively constant during evolution and, therefore, dependencies among the four bases can be predicted. In order to characterize the nature and to determine the degree of such dependencies, correlation analysis followed by principal component factorial analysis was conducted on a large sample of 5S rRNA sequences. The results show that the purine and pyrimidine contents tend to remain constant, so that A + G = Kpur and C + U = Kpyr. The composition of the four bases expressed now by Kpur/Kpyr relationships is also constant (Ks). These relationships imply that the behavior of the mutations in the variable sites of the molecule follows rules imposed by the chemical nature of the bases involved. Consequently, transition mutations would be more favored than substitutions in transversion sites and also than insertion-deletion (rare in 5S rRNAs), since transitions would not significantly alter the values of the Ks-index.

5S rRNA sequences of 12 species of flatworms: implications for the phylogeny of the Platyhelminthes

1995 ◽  
pp. 37-43
Author(s):  
B. I. Joffe ◽  
K. M. Valiejo Roman ◽  
V. Ya. Birstein ◽  
A. V. Troitsky
Keyword(s):  
5S Rrna ◽  
Rrna Sequences

scholarly journals Changes in the Bacterioplankton Community Structure from Southern Gulf of Mexico During a Simulated Crude Oil Spill at Mesocosm Scale

2019 ◽  
Vol 7 (10) ◽  
pp. 441 ◽  
Author(s):  
Sonia S. Valencia-Agami ◽  
Daniel Cerqueda-García ◽  
Sébastien Putzeys ◽  
María Magdalena Uribe-Flores ◽  
Norberto Ulises García-Cruz ◽  
...  
Keyword(s):  
Community Structure ◽  
Gulf Of Mexico ◽  
Crude Oil ◽  
Oil Spill ◽  
Initial Time ◽  
P Value ◽  
Sequencing Analysis ◽  
Hydrocarbonoclastic Bacteria ◽  
Bacterioplankton Community ◽  
Southern Gulf Of Mexico

The southern Gulf of Mexico (sGoM) is highly susceptible to receiving environmental impacts due to the recent increase in oil-related activities. In this study, we assessed the changes in the bacterioplankton community structure caused by a simulated oil spill at mesocosms scale. The 16S rRNA gene sequencing analysis indicated that the initial bacterial community was mainly represented by Gamma-proteobacteria, Alpha-proteobacteria, Flavobacteriia, and Cyanobacteria. The hydrocarbon degradation activity, measured as the number of culturable hydrocarbonoclastic bacteria (CHB) and by the copy number of the alkB gene, was relatively low at the beginning of the experiment. However, after four days, the hydrocarbonoclastic activity reached its maximum values and was accompanied by increases in the relative abundance of the well-known hydrocarbonoclastic Alteromonas. At the end of the experiment, the diversity was restored to similar values as those observed in the initial time, although the community structure and composition were clearly different, where Marivita, Pseudohongiella, and Oleibacter were detected to have differential abundances on days eight–14. These changes were related with total nitrogen (p value = 0.030 and r2 = 0.22) and polycyclic aromatic hydrocarbons (p value = 0.048 and r2 = 0.25), according to PERMANOVA. The results of this study contribute to the understanding of the potential response of the bacterioplankton from sGoM to crude oil spills.

scholarly journals A Study of Population Size and Activity Patterns and Their Relationship to the Prey Species of the Eurasian Lynx Using a Camera Trapping Approach

Animals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 864
Author(s):  
Xiaoming Tang ◽  
Shupei Tang ◽  
Xiaoyu Li ◽  
Dalai Menghe ◽  
Wuliji Bao ◽  
...  
Keyword(s):  
Community Structure ◽  
Population Size ◽  
Habitat Management ◽  
Activity Patterns ◽  
Management Strategies ◽  
Camera Trapping ◽  
Ecosystem Functions ◽  
Lynx Lynx ◽  
Eurasian Lynx ◽  
Different Seasons

Revealing the behavioral relationships between predators and their prey is fundamental in understanding the community structure and ecosystem functions of such animals. This study aimed at detecting the population size and activity patterns of Eurasian lynx (Lynx lynx) (along with its prey) by camera trapping monitoring from 2014 to 2017 at the Saihanwula nature reserve in central Inner Mongolia. The total effective trapping days were 29,892 and 20 lynx were identified from 343 trapping photos based on the inner side patterns of their forelimbs. The daily activity rhythms of the lynx overlapped with those of different prey in different seasons. The yearly activity pattern of the lynx was influenced by its main prey’s biology. In conclusion, this study reveals that the activity patterns of the top predator matched those of its prey in different time periods. Habitat management strategies promoting the restoration of prey communities would benefit the lynx in maintaining a stable community structure.

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