Environmental dissimilarity over time in a large subtropical shallow lake is differently represented by phytoplankton functional approaches

2018 ◽  
Vol 69 (1) ◽  
pp. 95 ◽  
Author(s):  
Juliana E. Bohnenberger ◽  
Lúcia R. Rodrigues ◽  
David da Motta-Marques ◽  
Luciane O. Crossetti
Keyword(s):  
Shallow Lake ◽  
Functional Group ◽  
Environmental Variability ◽  
Life Forms ◽  
Total Biomass ◽  
Coastal Lake ◽  
Effective System ◽  
Physical And Chemical Variables ◽  
Physical And Chemical

The aim of the present study was to understand how different phytoplankton functional approaches responded to environmental variability in a large shallow lake, namely Lake Mangueira, in southern Brazil. This coastal lake has a maximum depth of 7m and is ~90km long and ~3–10km wide. Physical and chemical variables, maximum linear dimension, life forms, functional and morphofunctional groups of phytoplankton were analysed. The results showed that the phytoplankton were primarily comprised Cyanobacteria (63.9%), followed by middle-sized algae (21–50μm; 46.7%) and colonial non-flagellated taxa (63%). The highest percentage of total biomass was accounted for by the functional group ‘K’ (as classified by Reynolds et al. 2002; 36.3%), large mucilaginous colonies (46.79%) according to morphologically based functional classification and other large colonies (mostly non-vacuolated; 36.7%) according to morphofunctional classification. Dissimilarity analysis indicated a significant correlation between abiotic data and functional approaches (P=0.001). The dissimilarity in the functional compositions of phytoplankton was related to nutrient and light conditions, especially to silicon content and water transparency, in all functional approaches. The highest correlation with abiotic variables was seen for morphologically based functional group community structure, although the functional group composition of phytoplankton sensu Reynolds et al. seemed to be the most effective system in describing environmental variability in Lake Mangueira over the long term.

Early patterns of heterotroph activity in conifer logs

1988 ◽  
Vol 94 ◽  
pp. 33-43 ◽  
Author(s):  
Steven E. Carpenter ◽  
Mark E. Harmon ◽  
Elaine R. Ingham ◽  
Rick G. Kelsey ◽  
John D. Lattin ◽  
...  
Keyword(s):  
Bark Beetles ◽  
Functional Group ◽  
Seasonal Fluctuations ◽  
Term Study ◽  
Long Term Study ◽  
Initial Effect ◽  
Chemical States ◽  
Physical And Chemical ◽  
Decomposer Community

SynopsisFindings from the first two years of a long-term study of conifer log decomposition are presented. Log decomposition is regulated by the physical and chemical states, and development of decomposer foodwebs. The functional group with the greatest initial effect on the log is the channelisers, represented in our study by ambrosia and bark beetles. They not only create multitudes of channels into the logs but vector the initial decomposer community. Ambrosia beetles exclude certain elements of the decomposer community from channels until they vacate the log, at the end of their reproductive phase. The foodweb during the early stages of decomposition includes nitrogen-fixing and other bacteria, fungi, protozoa, nematodes, and arthropods. Seasonal fluctuations of temperature and moisture are hypothesised to work in tandem to modulate the activities of the decomposer community.

Development and Stability of Fish Assemblages after Lime Treatment

1991 ◽  
Vol 48 (4) ◽  
pp. 546-554 ◽  
Author(s):  
Magnus Appelberg ◽  
Erik Degerman
Keyword(s):  
Species Interactions ◽  
Fish Assemblages ◽  
Negative Relationship ◽  
Habitat Diversity ◽  
Long Term Effects ◽  
Lime Treatment ◽  
Physical And Chemical Variables ◽  
Physical And Chemical ◽  
Species Proportions

Long-term effects of limestone treatment on fish populations in acidified lakes in Sweden have been examined since 1983 to assess the development and stability of fish assemblages after lime treatment. In total, 77 lakes were sampled twice using standardized methods between 1983 and 1988. The lakes were limed 1–16 yr before the second sampling. Physical and chemical variables and the fish data were reduced using PCA ordination and the resulting relationships were analyzed using linear regression and ANOVA. Relationships between the fish assemblage characteristics and the environmental factors were highly dependent on the species composition of the assemblages. The number and diversity of fish species were correlated with both the extent of acidification and habitat diversity of the lakes. The importance of species interactions after lime treatment was suggested by a negative relationship between changes in the scores of community along the first component of the fish PCA and changes along two of the other species components between the two samplings. Despite a weak tendency towards reduced variability in species proportions as time passed since the first liming, the development of community stability, expressed as lack of change in species proportions, was insignificant.

scholarly journals Persistence of Selected Spartina alternifloraRhizoplane Diazotrophs Exposed to Natural and Manipulated Environmental Variability

2000 ◽  
Vol 66 (11) ◽  
pp. 4625-4633 ◽  
Author(s):  
Christopher E. Bagwell ◽  
Charles R. Lovell
Keyword(s):  
Salt Marshes ◽  
Functional Group ◽  
Environmental Variability ◽  
Distribution Patterns ◽  
Functional Stability ◽  
Available Nitrogen ◽  
Niche Specialization ◽  
Reduction Assay ◽  
Experimental Treatments

ABSTRACT Rhizoplane-rhizosphere nitrogen-fixing microorganisms (diazotrophs) are thought to provide a major source of biologically available nitrogen in salt marshes dominated bySpartina alterniflora. Compositional and functional stability has been demonstrated for this important functional group; however, the quantitative responses of specific diazotroph populations to environmental variability have not been assessed. Changes in the relative abundances of selected rhizoplane diazotrophs in response to long-term fertilization were monitored quantitatively by reverse sample genome probing. Fertilization stimulated Spartina, with plant height nearly tripling after 1 year. Fertilization also resulted in significant changes in interstitial porewater parameters. Diazotrophic activity (acetylene reduction assay) was sensitive to the fertilization treatments and was inhibited in some plots on several sampling dates. However, inhibition was never consistent across all of the replicates within a treatment and activity always recovered. The rhizoplane diazotrophs were quite responsive to environmental variability and to experimental treatments, but none were displaced by either environmental variability or experimental treatments. All strains were detected consistently throughout this study, and extensive spatial heterogeneity in the distribution patterns of these organisms was observed. The physiological traits that differentiate the diazotroph populations presumably support competitiveness and niche specialization, resulting in the observed resilience of the diazotroph populations in the rhizosphere.

scholarly journals Feeding ecology of a stream fish assemblage in an Atlantic Forest remnant (Serra do Japi, SP, Brazil)

2009 ◽  
Vol 7 (1) ◽  
pp. 65-76 ◽  
Author(s):  
Ana Paula Pozzo Rios Rolla ◽  
Katharina Eichbaum Esteves ◽  
Antônio Olinto Ávila-da-Silva
Keyword(s):  
Atlantic Forest ◽  
Fish Assemblage ◽  
Wide Distribution ◽  
Southeastern Brazil ◽  
Total Biomass ◽  
Trophic Groups ◽  
Forest Remnant ◽  
Physical And Chemical Variables ◽  
Diverse Community ◽  
Physical And Chemical

This study aimed to characterize the trophic structure of the fish assemblage in streams of the Serra Japi, an ecotonal area between the Atlantic Forest and inland forests of São Paulo State, Southeastern Brazil. Fish were collected with electrofishing equipment in 15 sites covering different regions, substrate types and riparian vegetation, distributed throughout the Caguaçú River, Caxambú, Piraí and Guapeva River micro-basins, during the rainy (January/February) and dry season (June) of 2007. The 589 specimens analyzed from 22 species, were assigned to different trophic groups, discriminated through a matrix of similarity, based on the food index (IAi). The results show the formation of seven groups with a predominance of insectivorous and omnivorous species, followed by detritivores, piscivores, omnivore-carnivores and herbivores, which consumed mostly items of autochthonous origin, where algae and young insects were dominant. Canonical correspondence analysis (CCA), correlating the biomass of trophic groups to environmental variables, showed that omnivores, insectivores and omnivore-carnivores displayed a wide distribution, while detritivores, herbivores and piscivores were restricted to specific locations, related to different physical and chemical variables as total nitrogen, conductivity and temperature. Despite the increase in total biomass at the most urbanized sites, the results indicate that the streams maintain a diverse community, suggesting that most of them are in preserved conditions.

Zooplankton Species Associations in Quebec Lakes: Variation with Abiotic Factors, Including Natural and Anthropogenic Acidification

1990 ◽  
Vol 47 (1) ◽  
pp. 110-121 ◽  
Author(s):  
Bernadette Pinel-Alloul ◽  
Ginette Méthot ◽  
Ghislain Verreault ◽  
Yvan Vigneault
Keyword(s):  
Environmental Variability ◽  
Abiotic Factors ◽  
Zooplankton Species ◽  
Separate Species ◽  
Environmental Property ◽  
Lake Morphology ◽  
Species Abundances ◽  
Physical And Chemical Variables ◽  
Abiotic Variables ◽  
Physical And Chemical

Abundances and biomass of 38 zooplankton species and accompanying abiotic data from 54 Quebec lakes were subjected to cluster and correlation analysis to determine (1) characteristic zooplankton associations of cooccurring species, (2) relative importance of abiotic variables in lake typology, and (3) relationships between the integrated environmental factors derived from lake morphometry, water quality, and acidification level, and the structure of zooplankton communities. The eight groups of species identified in the cluster analysis may be considered separate "species associations" characterized by distinct patterns of distribution in Quebec lakes. Differences in mean pH and sulphate concentrations can be detected between groups of lakes representing the different species associations. Factor analysis produced seven factor scores which explain 82% of the total variance of the morphological, physical, and chemical variables. The distribution pattern of acidity or alkalinity represents the major feature in water chemistry variation, but lake morphology also account for the observed environmental variability. Each factor represents an integrated environmental property correlated with a set of colinear abiotic variables. These factors are correlated with zooplankton species abundances and biomass. The community structure, whether expressed in size classes or in trophic groups, tends to vary among sets of lakes of different pH.

Multivariate analysis of long term water quality changes of shallow Lake Balaton

2006 ◽  
Vol 29 (4) ◽  
pp. 2051-2055 ◽  
Author(s):  
G. Kiss ◽  
Gy. Dévai ◽  
B. Tóthmérész ◽  
A. Szabó
Keyword(s):  
Water Quality ◽  
Multivariate Analysis ◽  
Shallow Lake ◽  
Lake Balaton ◽  
Quality Changes

scholarly journals Treated wastewater irrigation effects on soil hydraulic conductivity and aggregate stability of loamy soils in Israel

2015 ◽  
Vol 63 (1) ◽  
pp. 47-54 ◽  
Author(s):  
Karsten Schacht ◽  
Bernd Marschner
Keyword(s):  
Hydraulic Conductivity ◽  
Chemical Properties ◽  
Aggregate Stability ◽  
Treated Wastewater ◽  
Soil Aggregate Stability ◽  
Irrigation Effects ◽  
Physical And Chemical ◽  
The Impact

Abstract The use of treated wastewater (TWW) for agricultural irrigation becomes increasingly important in water stressed regions like the Middle East for substituting fresh water (FW) resources. Due to elevated salt concentrations and organic compounds in TWW this practice has potential adverse effects on soil quality, such as the reduction of hydraulic conductivity (HC) and soil aggregate stability (SAS). To assess the impact of TWW irrigation in comparison to FW irrigation on HC, in-situ infiltration measurements using mini disk infiltrometer were deployed in four different long-term experimental orchard test sites in Israel. Topsoil samples (0-10 cm) were collected for analyzing SAS and determination of selected soil chemical and physical characteristics. The mean HC values decreased at all TWW sites by 42.9% up to 50.8% compared to FW sites. The SAS was 11.3% to 32.4% lower at all TWW sites. Soil electrical conductivity (EC) and exchangeable sodium percentage (ESP) were generally higher at TWW sites. These results indicate the use of TWW for irrigation is a viable, but potentially deleterious option, as it influences soil physical and chemical properties.

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