Effects of Irradiance on the Community Structure and Biomass of Algal Assemblages in Laboratory Streams

1987 ◽  
Vol 44 (9) ◽  
pp. 1640-1648 ◽  
Author(s):  
Alan D. Steinman ◽  
C. David McIntire
Keyword(s):  
Community Structure ◽  
Detrended Correspondence Analysis ◽  
Direct Result ◽  
Photon Flux ◽  
Taxonomic Structure ◽  
Natural Streams ◽  
Laboratory Streams ◽  
Algal Assemblages ◽  
Benthic Stream ◽  
Study Laboratory

Studies in natural streams have implicated irradiance as a factor which has a strong influence on the dynamics of algal communities. In this study, laboratory streams were used in a replicated, experimental design to investigate whether differences in algal biomass, taxonomic structure, and physiognomy result from exposure to different irradiances. Effects of four photon flux densities (15, 50, 150, and 400 μE∙m−2∙s−1) on locally collected benthic stream algae were monitored over a 48-d period. Biomass increased in all streams during the experiment, but the streams exposed to the highest irradiance had 25 times more biomass at the end of the experiment than the channels exposed to the lowest irradiance. Although diatoms were the dominant algal class in all streams, the relative abundance of chlorophytes was much greater in streams exposed to 150 and 400 μE∙m−2∙s−1 than in channels treated with 15 and 50 μE∙m−2∙s−1 Detrended correspondence analysis indicated that the successional trajectories of assemblages exposed to low irradiances were quite distinct from those of assemblages treated with high irradiances. Observations of assemblage physiognomy by scanning electron microscopy revealed that at low irradiances, a densely packed understory of adnate diatoms, with a few overstory diatoms, covered the tile surface. At high irradiances, tiles were overlaid with thick algal mats, composed of filamentous and coenobic chlorophytes and diatoms of various growth forms (rosette, chain-forming, and solitary). The experimental results suggested that differences in biomass and community structure among the laboratory assemblages were a direct result of light energy, and that irradiance is a major factor influencing algal dynamics in lotic ecosystems.

Effects of Herbivore Type and Density on Taxonomic Structure and Physiognomy of Algal Assemblages in Laboratory Streams

1987 ◽  
Vol 6 (3) ◽  
pp. 175-188 ◽  
Author(s):  
Alan D. Steinman ◽  
C. David McIntire ◽  
Stanley V. Gregory ◽  
Gary A. Lamberti ◽  
Linda R. Ashkenas
Keyword(s):  
Taxonomic Structure ◽  
Laboratory Streams ◽  
Algal Assemblages

scholarly journals Changes in the phytoplankton diversity of two oxbow lakes in a big city: a case study of Wrocław (Poland)

2016 ◽  
Vol 43 (1) ◽  
pp. 13-26
Author(s):  
Dorota Richter ◽  
Paulina Bączek
Keyword(s):  
Taxonomic Diversity ◽  
Water Bodies ◽  
Taxonomic Structure ◽  
Oxbow Lakes ◽  
Phytoplankton Diversity ◽  
Big City ◽  
Algal Assemblages ◽  
Cyanobacteria And Algae ◽  
The City

Abstract The subject of this study is to analyse changes in the taxonomic structure and development intensity of phytoplankton and, thus, to determine the diversity of cyanobacteria and algae along with the trophy state of two oxbow lakes in the Wrocław area (south-western Poland). The analysis of samples and data from previous years showed a total of 244 cyanobacteria and algae species within these two lakes. The species composition changed significantly in both of them – there were found 90 species new to the studied flora (37% of current flora) and 74 species which were previously recorded. The diversity of cyanobacteria and algae reflects the conditions in these water bodies and each change in ecological conditions (e.g., anthropological dangers) is reflected by a change in the phytoplankton assemblage structure. Consequently, knowledge of taxonomic diversity is useful in monitoring water bodies to preserve them in good conditions. Both studied oxbow lakes belong to eutrophic ecosystems as evidenced by their phycoflora, which is rich in species characteristic of high-trophy water, and recorded water blooms. The analysis of changes in cyanobacterial and algal assemblages in these lakes was also a basis for determining their trophy and finding it to be progressively eutrophic. Regular phycological studies of Wrocław numerous water bodies are essential and, in the future, will allow us to protect them and to react quickly in case of danger to these ecosystems. It will also allow us to study eutrophication processes in the water bodies that are crucial to the city.

Epiphyton of oligotrophic lakes of Leningrad region

2021 ◽  
pp. 71-79
Author(s):  
Elena V. Stanislavskaya
Keyword(s):  
Community Structure ◽  
Dominant Species ◽  
Taxonomic Composition ◽  
Species Level ◽  
Taxonomic Structure ◽  
Leningrad Region ◽  
Oligotrophic Lakes ◽  
Epiphytic Algae ◽  
Lake Ecosystems ◽  
Epiphytic Communities

Here are results of investigation of taxonomic composition, community structure and dominant species of epiphytic algae in 12 oligotrophic lakes located in different geomorphic regions of Leningrad region. In summer epiphytic communities there were 385 algal taxa, they belonged to 6 taxonomic divisions: Cyanophyta (Cyanoprokaryota) – 50 (13%), Bacillaryophyta – 175 (45%), Chlorophyta – 37 (10%), Charophyta – 118 (30%), Xanthophyta – 4 (1,55%), Rhodophyta – 1 (0,45%). The taxonomic structure of each lake was predominant diatoms and desmids, but the biomass was dominated by zygnems and green algae. In total, the taxonomic composition of the epiphyton in the studied lakes is similar, the differences are revealed at the species level. The structure of dominanting epiphyton complex was rather constant and composed by a small number of species. The greatest contribution to the epiphyton was made by Tabellaria flocculosa and species of the genus Bulbochaete. The structure of the epiphyton reflects the undisturbed nature of lake ecosystems, as well as their northern location.

HABITAT CHARACTERISTICS AND GRASSHOPPER COMMUNITY DYNAMICS ON MIXED-GRASS RANGELAND

1991 ◽  
Vol 123 (1) ◽  
pp. 89-105 ◽  
Author(s):  
Mark A. Quinn ◽  
R.L. Kepner ◽  
D.D. Walgenbach ◽  
R.A. Bohls ◽  
P.D. Pooler ◽  
...  
Keyword(s):  
Community Structure ◽  
Community Dynamics ◽  
Detrended Correspondence Analysis ◽  
Bouteloua Gracilis ◽  
Community Change ◽  
Habitat Characteristics ◽  
Agropyron Smithii ◽  
Spatial Gradients ◽  
Mixed Grass ◽  
The Difference

AbstractA study was conducted in Butte County of western South Dakota to determine the relationships between habitat characteristics and spatial and temporal changes in community structure of grasshoppers on mixed-grass rangeland. Detrended correspondence analysis (DCA) of 29 undisturbed grasshopper communities and correlation analysis of DCA axis values and habitat variables denned specific spatial gradients underlying the community structure of grasshoppers. Results indicated that grasshopper communities changed along a primary gradient of percentage of coverage of grasses, particularly Buchloe dactyloides (Nutt.) Engelm., and a secondary gradient of percentage composition of clay and sand in the soil.DCA of 24 grasshopper communities sampled in 1986 and 1987, multiple regression analysis, and factor analysis were used to determine the relationships between specific habitat characteristics and changes in communities of grasshoppers treated with either a nonselective insecticidal spray (malathion) or a selective insecticidal bait (bran bait with carbaryl). Results indicated that between-year change in community composition, or the difference between post-treatment communities in 1986 and 1987, was positively correlated with percentage of coverage of total grasses and forbs. Community malleability, defined as the tendency of a community to return to its predisturbed state, was greater in habitats with high coverages of Agropyron smithii Rydb. and Carex spp., low coverage of Bouteloua gracilis (H.B.K.) Lag. ex Steud., and low species richness of grasses. Our results emphasize the importance of habitat characteristics in structuring undisturbed grasshopper communities and in community change after perturbation with insecticides.

Comparison of the woody flora and soils of six areas of montane semideciduous forest in southern Minas Gerais, Brazil

1994 ◽  
Vol 51 (3) ◽  
pp. 355-389 ◽  
Author(s):  
A. T. Oliveira-Filho ◽  
E. A. Vilela ◽  
M. L. Gavilaness ◽  
D. A. Carvalho
Keyword(s):  
Community Structure ◽  
Detrended Correspondence Analysis ◽  
Floristic Composition ◽  
Rio Grande ◽  
Minas Gerais ◽  
Southeastern Brazil ◽  
Semideciduous Forest ◽  
Qualitative And Quantitative ◽  
Gallery Forests ◽  
Upper Rio Grande

Qualitative and quantitative descriptions of the woody flora and soil analyses are provided for six areas of montane semideciduous forest in the upper Rio Grande region, southern Minas Gerais, Brazil. Comparisons are made of the floristic composition of these six areas and 24 other forest areas of southeastern Brazil using ordination by detrended correspondence analysis (DCA) and hierarchical classifications, both agglomerative (upgma) and divisive (twinspan). The variation in community structure of five of the six forest areas was analysed using a two-way table yielded by twinspan. The floristic analyses indicated the strongest link between the forests of the upper Rio Grande region and other montane forest formations of southeastern Brazil as well as secondary links with the gallery forests that extend into the cerrado domain and the submontane semideciduous forests of the Rio Parana basin. Variations in community structure among the five forest areas were apparently associated mainly with riverside effects and soil fertility.

scholarly journals Impacts of a novel shellfishing gear on macrobenthos in a marine protected area: pump-scoop dredging in Poole Harbour, UK

2017 ◽  
Vol 31 ◽  
pp. 5 ◽  
Author(s):  
Leo J. Clarke ◽  
Luciana S. Esteves ◽  
Richard A. Stillman ◽  
Roger J.H. Herbert
Keyword(s):  
Community Structure ◽  
Protected Area ◽  
Marine Protected Area ◽  
Fishing Effort ◽  
Economic Benefits ◽  
Manila Clam ◽  
Direct Result ◽  
Monitoring Site ◽  
Hediste Diversicolor ◽  
The Impact

Understanding the impact of bottom-fishing gears at various scales and intensities on habitats and species is necessary to inform management. In Poole Harbour, UK, a multiple use marine protected area, fishermen utilise a unique ̋“pump-scoop” dredge to harvest the introduced Manila clam Ruditapes philippinarum. Managers need to balance the socio-economic benefits of the fishery with ecological concerns across the region, which has required a revision of by-laws that include both spatial and temporal measures. Within an operational fishery, we used a Before-After-Control-Impact sampling design to assess the impacts of pump-scoop dredging on benthic physical characteristics and community structure in an area where there was no dredging, an area newly opened to dredging and an area subject to high levels of historic dredging. A sampling grid was used in each area to best capture any fishing effort in the newly opened area. Core samples were taken to a depth of 30 cm within intertidal mudflats. A significant loss of fine sediments was observed in the site subject to high intensity dredging and a significant change in community structure also occurred in both dredged sites throughout the study period. In the newly opened site this was characterised by a relative increase in species richness, including increased abundance of annelid worms, notably Hediste diversicolor and Aphelochaeta marioni and a decline in the abundance of the bivalve mollusc Abra tenuis. These changes, albeit relatively small, are attributed to physical disturbance as a direct result of pump-scoop dredging, although no difference in the classification of the biotope of the site was observed. This is of particular interest to managers monitoring site condition within areas under the new by-laws as the Manila clam is spreading to other protected estuaries in the region.

scholarly journals Community structure and productivity of subtidal turf and foliose algal assemblages

2009 ◽  
Vol 388 ◽  
pp. 1-11 ◽  
Author(s):  
RJ Miller ◽  
DC Reed ◽  
MA Brzezinski
Keyword(s):  
Community Structure ◽  
Algal Assemblages

scholarly journals Can nesting waterbirds influence the community structure of macroinvertebrates in southern Brazilian intermittent wetlands?

2020 ◽  
Vol 110 ◽  
Author(s):  
Daniela C. Zardo ◽  
Marcela M. Souza ◽  
Mateus M. Pires ◽  
Cristina Stenert ◽  
Leonardo Maltchik
Keyword(s):  
Community Structure ◽  
Total Dissolved Solids ◽  
Taxonomic Structure ◽  
Macroinvertebrate Communities ◽  
Water Turbidity ◽  
Physicochemical Variables ◽  
Intermittent Wetlands ◽  
Water And Sediment ◽  
Population Sizes ◽  
Water Nutrients

ABSTRACT The main goal of this study was to test the effect of the presence of nesting waterbirds on the taxonomic structure (richness, abundance and composition) of macroinvertebrate communities in southern Brazilian wetlands. Macroinvertebrate communities were seasonally sampled in eight intermittent wetlands differing according to the occurrence of nesting colonies of waterbirds (four with the presence of rookeries; four without). The influence of nutrients and water and sediment physicochemical variables on macroinvertebrate communities was also assessed. The community structure of aquatic macroinvertebrates was not affected by the presence of colonies of nesting waterbirds. Rather, macroinvertebrate communities varied seasonally and they were influenced by water-level environmental variables. Richness and composition changed among seasons and were influenced by nutrients and water physicochemical variables. Water turbidity and total dissolved solids influenced macroinvertebrate richness, while water nutrients affected macroinvertebrate abundance. Our results indicate that the lack of effect of nesting waterbirds on macroinvertebrates is possibly due to the variation in the composition of avian species and their reduced population sizes, and in such cases, any effects of birds on macroinvertebrates can be overridden by water chemistry and seasonal changes in intermittent wetlands.

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.

scholarly journals Can Rock-Rubble Groynes Support Similar Intertidal Ecological Communities to Natural Rocky Shores?

Land ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 131
Author(s):  
Paul Holloway ◽  
Richard Field
Keyword(s):  
Community Structure ◽  
Detrended Correspondence Analysis ◽  
Parallel Analysis ◽  
Rocky Shores ◽  
Ecological Communities ◽  
Rock Pool ◽  
Coastal Structures ◽  
Abundance Data ◽  
Species Groups ◽  
The Uk

Despite the global implementation of rock-rubble groyne structures, there is limited research investigating their ecology, much less than for other artificial coastal structures. Here we compare the intertidal ecology of urban (or semi-urban) rock-rubble groynes and more rural natural rocky shores for three areas of the UK coastline. We collected richness and abundance data for 771 quadrats across three counties, finding a total of 81 species, with 48 species on the groynes and 71 species on the natural rocky shores. We performed three-way analysis of variance (ANOVA) on both richness and abundance data, running parallel analysis for rock and rock-pool habitats. We also performed detrended correspondence analysis on all species to identify patterns in community structure. On rock surfaces, we found similar richness and abundance across structures for algae, higher diversity and abundance for lichen and mobile animals on natural shores, and higher numbers of sessile animals on groynes. Rock-pool habitats were depauperate on groynes for all species groups except for sessile animals, relative to natural shores. Only a slight differentiation between groyne and natural shore communities was observed, while groynes supported higher abundances of some ‘at risk’ species than natural shores. Furthermore, groynes did not differ substantially from natural shores in terms of their presence and abundance of species not native to the area. We conclude that groynes host similar ecological communities to those found on natural shores, but differences do exist, particularly with respect to rock-pool habitats.

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