scholarly journals Diet and capture of Hypostomus strigaticeps (Siluriformes, Loricariidae) in a small brazilian stream: relationship with limnological aspects

2006 ◽  
Vol 66 (1a) ◽  
pp. 25-33 ◽  
Author(s):  
I. B. Cardone ◽  
S. E. Lima-Junior ◽  
R. Goitein
Keyword(s):  
Electrical Conductivity ◽  
Dissolved Oxygen ◽  
Environmental Conditions ◽  
Organic Material ◽  
Environmental Variables ◽  
Polluted Site ◽  
Fecal Coliforms ◽  
Total Coliforms ◽  
Food Items ◽  
Limnological Parameters

The purpose of this study is to ascertain whether variations in the limnological parameters of the Corumbataí river resulting from the discharge of a variety of wastes into its waters may be responsible for spatial shifts in the diet and capture of the armored catfish Hypostomus strigaticeps (Regan, 1907). Individuals were collected over a period of two years from two sites with similar physical, albeit distinct limnological characteristics. As a whole, the environmental variables (temperature, pH, dissolved oxygen, electrical conductivity, and total coliforms and fecal coliforms) of the two sites were found to vary significantly. The food items found in the guts of these armored catfish (sediments, diatoms, fungi hyphae, chlorophytes, cyanophytes and non-identified material) ranked differently in samples from the two sites. In the more polluted (site B), diatoms and chlorophytes ranked higher in the diet than in that of individuals caught in the more preserved location (site A). This fact may be related to the greater amount of organic material found at site B, which provides favorable environmental conditions for such algae and, consequently, for algivorous fishes. Even so, fewer fish were captured at site B than at site A, suggesting that although food is more abundant in the more polluted site, its limnological conditions appear, on the whole, to be less beneficial than the conditions at site A.

scholarly journals Bacteriological and physical quality of fiche drinking water from households and reservoirs, Oromia, Ethiopia

2021 ◽  
Author(s):  
Israel Sebsibe ◽  
Birhanu Degaga ◽  
Gezahegn Feye ◽  
Tsige Tekle
Keyword(s):  
Electrical Conductivity ◽  
Drinking Water ◽  
Experimental Analysis ◽  
Total Dissolved Solids ◽  
Fecal Coliforms ◽  
World Health ◽  
Wet Season ◽  
Dissolved Solids ◽  
Total Coliforms ◽  
Water Handling

Abstract Drinking water is the major source of bacteria pathogens in developing countries along with poor sanitation and contamination of food with a pathogen. More than half of the population of the country uses unimproved sanitation facilities while 36% of them practiced open defecation. The aim of the study was to investigate the suitability of public water for drinking. The study is designed to include a survey of 90 respondents and experimental analysis of 170 water samples from households and reservoirs. Water quality parameters, such as temperature, electrical conductivity, turbidity, total dissolved solids, and bacteriological parameters like total coliforms (TC) and fecal coliforms (FC) were determined. Many of the respondents (88.8%) remarked that the water has no smells, tastes, and color. The experimental analysis confirmed that temperature (19.7 °C), electrical conductivity (269.63 μS/cm), turbidity (1.17 NTU), and total dissolved solids (134.3 mg/L) were found below the prescribed limit of World Health Organization guidelines for drinking water. Total coliforms (9.29 CFU/100 mL) and fecal coliforms (5.07 CFU/100 mL) were detected from pipe water sources during the wet season showing non-compliance with the guidelines. The reservoir samples were free from bacterial contamination. The main point of drinking water contamination was the household where unsafe water handling practice was a common habit in the study area. Hence, awareness conception training on safe water handling practices is highly recommended for the communities.

scholarly journals Ecological classification of the freshwater Ostracoda (Crustacea) based on physicochemical properties of waters and habitat preferences

2018 ◽  
Vol 54 ◽  
pp. 26 ◽  
Author(s):  
Okan Külköylüoğlu ◽  
Mehmet Yavuzatmaca ◽  
Derya Akdemir ◽  
Ebru Çelen ◽  
Nurhayat Dalkıran
Keyword(s):  
Electrical Conductivity ◽  
Dissolved Oxygen ◽  
Water Temperature ◽  
Environmental Variables ◽  
Habitat Preferences ◽  
Habitat Type ◽  
Alpha Diversity ◽  
Abundant Species ◽  
Critical Issue ◽  
Cosmopolitan Species

The relationship between ecological characteristic of freshwater ostracods and their habitat preferences has been a critical issue for understanding of both current and past aquatic conditions. To evaluate this idea, 121 water bodies with 11 different habitat types were randomly sampled in the province of Kütahya. Water quality measurements indicated high to low (Ca2+ > Mg2+ > Na+) cations and relatively low (SO42− > Cl− > F−) anion concentrations with Ca2+ being the dominant ion. Sixteen of 23 species were new reports for the area. Alpha diversity (H′ = 3.64) was found relatively high. Four most abundant species with ca. 93% of similarities contributed highest alpha values in warm to cooler (lower than 25 °C), alkaline (pH 8.22), and fresh to slightly brackish waters. Heterocypris salina and Ilyocypris bradyi also revealed the highest tolerances for electrical conductivity. Based on habitat type, species were clustered into three main groups (I–III). Canonical Correspondence Analyses explained about 57.4% of correlation between species and environmental variables. Redox potential, pH, water temperature and electrical conductivity were found to be the most effective factors on species occurrences while habitat type and dissolved oxygen were not effective. Total number of species showed strong negative and positive relationships with water temperature and dissolved oxygen, respectively. Results clearly showed that cosmopolitan species exhibited relatively wide tolerance ranges to different environmental variables. Accordingly, having wide tolerance ranges seems to provide advantages to cosmopolitan species, increasing their survival chances in a variety of habitats.

scholarly journals Annelida (Oligochaeta and Aphanoneura) from the Natural Reserve of Isla Martín García (upper Río de la Plata estuary, Argentina): biodiversity and response to environmental variables

2014 ◽  
Vol 74 (1) ◽  
pp. 128-136 ◽  
Author(s):  
II César
Keyword(s):  
Electrical Conductivity ◽  
Dissolved Oxygen ◽  
Water Temperature ◽  
Environmental Variables ◽  
Sampling Period ◽  
Abundant Species ◽  
Rio De La Plata ◽  
Río De La Plata ◽  
Oxygen Conductivity ◽  
La Plata

The Island of Martín García – located in the Upper Río de la Plata, to the south of the Uruguay River – is an outcropping of the crystalline basement. Fourteen sampling sites were selected, five along the littoral section of the island and nine in inland ponds. Four major environmental variables were measured: water temperature, dissolved oxygen, electrical conductivity, and pH. A total of 34 species of Oligochaeta and Aphanoneura were found, 30 belonging to Naididae plus one species each of the Narapidae, Lumbricidae, Enchytraeidae, and Aeolosomatidae. The thirteen most frequent species were: A. leydigi (30%), N. bonettoi (13%), L. hoffmeisteri (11%), N. variabilis(10%), S. trivandrana (6.5%), A. pigueti (5.6%), D. sawayai (4.5%), D. digitata(3.5%), C. diastrophus (2.7%), A. costatus (2.5%), P. longiseta (2.0%), Enchytraeidae (1.5%), and A. p. paraguayensis(1.4%). UPGMA clustering of species based on their occurrence in different ecological conditions revealed two main species groups. Canonic-correspondence analysis (CCA) was conducted with the 15 most frequent and abundant species in the 9 sampling sites and the 4 environmental variables. Results from the CCA revealed that the order of fluctuation of the environmental variables during the sampling period was, from the greatest to the least: dissolved oxygen, conductivity, pH, and water temperature. Approximately 97.6% of the correlations between species and environmental variables were expressed on axis 1 of the ordination diagram. Species richness correlated with the four environmental variables in the following order, from the weakest to the strongest: water temperature, pH, electrical conductivity, and dissolved oxygen.

Bacterial Indicators and Environmental Factors as Related to Contamination of Oysters by Enteroviruses

1980 ◽  
Vol 43 (2) ◽  
pp. 99-101 ◽  
Author(s):  
CHARLES P. GERBA ◽  
SAGAR M. GOYAL ◽  
IRINA CECH ◽  
GREGORY F. BOGDAN
Keyword(s):  
Environmental Factors ◽  
Environmental Variables ◽  
Good Predictor ◽  
Gulf Coast ◽  
Enteric Viruses ◽  
Fecal Coliforms ◽  
Marine Waters ◽  
Bacterial Indicators ◽  
Total Coliforms ◽  
Significant Regression

Enteric viruses previously have been reported in marine waters and shellfish which met acceptable bacteriological standards for recreational use and shellfish harvesting. Unfortunately, previous data on occurrence of enteric viruses are limited and usually not quantitative. In this report, results of studies conducted along the upper Texas Gulf coast, where a substantial amount of quantitative virological data was collected, are compared to bacteriological indicators and other environmental factors on a statistical basis. A product-moment correlation matrix showed that there was a moderate correlation between viruses in water and total coliforms in water, total coliforms in oysters and fecal coliforms in oysters. However, presence of viruses in water was not found to be correlated with presence of viruses in oysters. The only significant regression coefficient found for the model relating the concentration of viruses in water to bacterial indicators and other environmental variables was concentration of coliforms in oysters. Multiple regression analysis showed that approximately 25% of the variance in the number of viruses detected in water was statistically accounted for by the linear correlation with the total coliforms in oysters. The amount of variation in the number of viruses explained by this indicator, however, was not large enough to make the concentration of coliforms in oysters a good predictor of the concentration of viruses in water. Furthermore, none of the bacterial or other environmental variables was found to be a good predictor of the concentration of viruses detected in oysters. Our failure to find a strong predictive relationship between viruses in marine water and in oysters, and the occurrence of viruses in high frequency in waters which met current bacteriological standards, indicate that these standards do not reflect the occurrence of enteroviruses in marine waters.

scholarly journals Benthic macrofauna and the limnological parameters of a first-order stream in Atlantic Forest of Brazilian Northeast

2014 ◽  
Vol 26 (1) ◽  
pp. 26-34 ◽  
Author(s):  
Janaina Câmara Siqueira da Cunha ◽  
Renato Galindo de Barros Filho ◽  
Rafael Pereira da Silva ◽  
Iris Gabrielly Arruda dos Santos ◽  
Gilberto Gonçalves Rodrigues
Keyword(s):  
Electrical Conductivity ◽  
Dissolved Oxygen ◽  
Water Temperature ◽  
Atlantic Forest ◽  
Ph Value ◽  
Sampling Effort ◽  
Order Stream ◽  
First Order ◽  
Structural Variables ◽  
Limnological Parameters

AIM: The present study aimed to elucidate if the water physical and chemical parameters from a first order stream of Biological Reserve of Saltinho from south Pernambuco induces in the distribution and abundance of benthic macroinvertebrates. METHODS: Both limnological parameters (pH-value, electrical conductivity, water temperature, turbidity, salinity and dissolved oxygen) and structural variables of aquatic habitat (substrate, food availability and flow velocity) influence the macroinvertebrates community structure. The creek is very small, with an approximate width of 1-3 m and a depth of 0.5 m. It was used a Surber sampler (100 mm) in three stretch of the creek, each one with two sampling units (s.u.) totaling six s.u. distant 50 m, with a sampling effort of five minutes per s.u.. The measurer multiparameter was used in order to obtain the water analysis (limnological parameters). RESULTS: From 11 taxa of macroinvertebrates found no significant correlation (p<0.05) was presented with pH-value, water temperature and salinity, but some taxa showed with electrical conductivity (EC), turbidity (TD) and dissolved oxygen (DO). Hemiptera abundance increases with decreasing DO; Ostracoda abundance increases with increasing EC and TD and the decrease in DO; and Trichoptera abundance increases with the decrease in EC and TD and the increase in DO. The stretches exhibited similarity in relation to the richness and abundance of macroinvertebrates and limnological parameters. The macroinvertebrates distribution in the stream not showed the same pattern, grouping s.u. of different stretch, because the habitat structural variables influenced the distribution. CONCLUSIONS: Therefore, the macroinvertebrates community varies according to abiotic factors in different limnological and structural parameters. This study is the first record of a work that associates benthic fauna and abiotic parameters at the Atlantic forest of Pernambuco.

scholarly journals The influence of dynamic environmental interactions on detection efficiency of acoustic transmitters in a large, deep, freshwater lake

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Natalie V. Klinard ◽  
Edmund A. Halfyard ◽  
Jordan K. Matley ◽  
Aaron T. Fisk ◽  
Timothy B. Johnson
Keyword(s):  
Study Design ◽  
Environmental Conditions ◽  
Power Output ◽  
Environmental Variables ◽  
Acoustic Telemetry ◽  
Detection Efficiency ◽  
Data Interpretation ◽  
Heterogeneous Environments ◽  
Depth Range ◽  
Dynamic Relationship

Abstract Background Acoustic telemetry is an increasingly common method used to address ecological questions about the movement, behaviour, and survival of freshwater and marine organisms. The variable performance of acoustic telemetry equipment and ability of receivers to detect signals from transmitters have been well studied in marine and coral reef environments to inform study design and improve data interpretation. Despite the growing use of acoustic telemetry in large, deep, freshwater systems, detection efficiency and range, particularly in relation to environmental variation, are poorly understood. We used an array of 90 69-kHz acoustic receivers and 8 sentinel range transmitters of varying power output deployed at different depths and locations approximately 100–9500 m apart for 215 days to evaluate how the detection efficiency of acoustic receivers varied spatially and temporally in relation to environmental conditions. Results The maximum distance that tags were detected ranged from 5.9 to 9.3 km. Shallow tags consistently had lower detection efficiency than deep tags of the same power output and detection efficiency declined through the winter months (December–February) of the study. In addition to the distance between tag and receiver, thermocline strength, surface water velocity, ice thickness, water temperature, depth range between tag and receiver, and number of fish detections contributed to explaining variation in detection efficiency throughout the study period. Furthermore, the most significant models incorporated interactions between several environmental variables and tag–receiver distance, demonstrating the complex temporal and spatial relationships that exist in heterogeneous environments. Conclusions Relying on individual environmental variables in isolation to interpret receiver performance, and thus animal behaviour, may be erroneous when detection efficiency varies across distances, depths, or tag types. As acoustic telemetry becomes more widely used to study ecology and inform management, it is crucial to understand its limitations in heterogeneous environments, such as freshwater lakes, to improve the quality and interpretation of data. We recommend that in situ range testing and retrospective analysis of detection efficiency be incorporated into study design for telemetry projects. Furthermore, we caution against oversimplifying the dynamic relationship between detection efficiency and environmental conditions for the sake of producing a correction that can be applied directly to detection data of tagged animals when the intended correction may not be justified.

scholarly journals Mollusks (Gastropoda and Bivalvia) of the Multiple-Use Reserve Martín García Island, Río de la Plata River: biodiversity and ecology

2012 ◽  
Vol 72 (1) ◽  
pp. 121-130 ◽  
Author(s):  
II César ◽  
SM Martín ◽  
A Rumi ◽  
M Tassara
Keyword(s):  
Dissolved Oxygen ◽  
Water Temperature ◽  
Environmental Variables ◽  
Sampling Period ◽  
Pomacea Canaliculata ◽  
Rio De La Plata ◽  
Multiple Use ◽  
Río De La Plata ◽  
Oxygen Conductivity ◽  
La Plata

The Island of Martin Garcia is located in the Upper Río de la Plata, to the south of mouth the Uruguay River. The aim of the present study was to analyse the biodiversity of the island freshwater mollusks and their relationships to environmental variables. Twelve sampling sites were selected, five were along the littoral section of the island and seven were Inland ponds. Seven major environmental variables were measured: water and air temperature, percentage of oxygen saturation, dissolved oxygen, electrical conductivity, total dissolved solids and pH. Twenty-seven mollusk species were found, Antillorbis nordestensis, Biomphalaria tenagophila tenagophila , B. t. guaibensis, B. straminea, B. peregrina, Drepanotrema kermatoides, D. cimex, D. depressissimum, Chilina fluminea, C. rushii, C. megastoma, Uncancylus concentricus, Hebetancylus moricandi, Stenophysa marmorata, Heleobia piscium, H. parchappii, Potamolithus agapetus, P. buschii, P. lapidum, Pomacea canaliculata, P. megastoma, Asolene platae, Corbicula fluminea, Eupera platensis, Pisidium sterkianum, P. taraguyense and Limnoperna fortunei. UPGMA clustering of species based on their occurrence in different ecological conditions revealed two main species groups. The Canonical Correspondence Analysis suggests that the species distribution is related to the physico-chemical condition of water. Axis two of the ordination diagram displayed the approximately 95.6% of the correlation between species and environmental variables. Dissolved oxygen, conductivity, water temperature and pH showed the highest fluctuations during the sampling period. The species richness (S) showed relationships mainly with water temperature and conductivity. The biodiversity of the gastropods and bivalves from Martín García Island amounts to up to 26 species. Among the Gastropoda, the Planorbidae family made the most sizeable contribution. The Lithogliphidae P. agapetus (26.28%) and P. buschii (9.50%) showed the highest relative frequencies of occurrence within the littoral environments, while the Planorbidae D. cimex (23.83%) and D. kermatoides (11.59%) likewise did so in the inland ponds.

Virus occurrence in municipal groundwater sources in Quebec, Canada

2007 ◽  
Vol 53 (6) ◽  
pp. 688-694 ◽  
Author(s):  
Annie Locas ◽  
Christine Barthe ◽  
Benoit Barbeau ◽  
Annie Carrière ◽  
Pierre Payment
Keyword(s):  
Drinking Water ◽  
Sampling Site ◽  
Enteric Viruses ◽  
Fecal Coliforms ◽  
Coliform Bacteria ◽  
Raw Water ◽  
Total Coliforms ◽  
Two Samples ◽  
Historic Data ◽  
Human Enteric Viruses

A 1 year study was undertaken on groundwater that was a source of drinking water in the province of Quebec, Canada. Twelve municipal wells (raw water) were sampled monthly during a 1 year period, for a total of 160 samples. Using historic data, the 12 sites were categorized into 3 groups: group A (no known contamination), group B (sporadically contaminated by total coliforms), and group C (historic and continuous contamination by total coliforms and (or) fecal coliforms). Bacterial indicators (total coliform, Escherichia coli , enteroccoci), viral indicators (somatic and male-specific coliphages), total culturable human enteric viruses, and noroviruses were analyzed at every sampling site. Total coliforms were the best indicator of microbial degradation, and coliform bacteria were always present at the same time as human enteric viruses. Two samples contained human enteric viruses but no fecal pollution indicators (E. coli, enterococci, or coliphages), suggesting the limited value of these microorganisms in predicting the presence of human enteric viruses in groundwater. Our results underline the value of historic data in assessing the vulnerability of a well on the basis of raw water quality and in detecting degradation of the source. This project allowed us to characterize the microbiologic and virologic quality of groundwater used as municipal drinking water sources in Quebec.

Evidence for physical and chemical stratification in Lake Untersee (central Dronning Maud Land, East Antarctica)

1997 ◽  
Vol 9 (1) ◽  
pp. 43-45 ◽  
Author(s):  
U. Wand ◽  
G. Schwarz ◽  
E. Brüggemann ◽  
K. Bräuer
Keyword(s):  
Electrical Conductivity ◽  
Dissolved Oxygen ◽  
Water Column ◽  
Water Body ◽  
East Antarctica ◽  
Bacterial Sulphate Reduction ◽  
Chemical Stratification ◽  
Dronning Maud Land ◽  
Physical And Chemical ◽  
Vertical Gradients

Lake Untersee is the largest freshwater lake in the interior of East Antarctica. It is a perennially ice-covered, max. 169 m deep, ultra-oligotrophic lake. In contrast to earlier studies, we found clear evidence for physical and chemical stratification in the summer of 1991–92. However, the stratification was restricted to a trough, c. 500 m wide and up to 105 m deep, in the south-western part of the lake. There, the water body was distinctly stratified as indicated by sharp vertical gradients of temperature, pH, dissolved oxygen, and electrical conductivity. The water column was anoxic below 80 m. The chemical stratification is also indicated by changes of ionic ratios. Moreover, there was some evidence for methanogenesis and bacterial sulphate reduction in Lake Untersee.

Distribution, feeding behaviour, and condition of Cape horse mackerel early life stages, Trachurus capensis, under different environmental conditions in the northern Benguela upwelling ecosystem

2014 ◽  
Vol 72 (2) ◽  
pp. 543-557 ◽  
Author(s):  
S. J. Geist ◽  
A. Kunzmann ◽  
H. M. Verheye ◽  
A. Eggert ◽  
A. Schukat ◽  
...  
Keyword(s):  
Dissolved Oxygen ◽  
Feeding Ecology ◽  
Environmental Conditions ◽  
Early Life ◽  
Early Life History ◽  
Horse Mackerel ◽  
Larval Phase ◽  
Recruitment Success ◽  
Wide Range ◽  
Variable Recruitment

Abstract Early life history (ELH) traits are key to understand variable recruitment success and hence the stock size of marine fish. One of the currently most puzzling ecosystems in this regard is the northern part of the Benguela Current upwelling system off Namibia. Here, populations of the formerly dominant pelagic species, sardine and anchovy, failed to recover during the last three decades after a dramatic decline. In contrast, Cape horse mackerel, Trachurus capensis, maintained a constant population size. Warming of the system and shoaling of hypoxic zones together with feedback loops within an altered foodweb are discussed to be responsible for this regime shift. In this study, we address the role of larval traits for the successful performance of the T. capensis population under the present environmental conditions with the focus on feeding ecology. We investigated seasonal variations of the geographical distribution, growth rate, feeding ecology, and nutritional condition of their ELH stages and examined relationships with water temperature, dissolved oxygen concentration, and micro-zooplankton composition. T. capensis' ELH stages showed a wide spatial and seasonal distribution, a preference for higher water temperatures (18–21°C) and presence over a wide range of dissolved oxygen concentrations (0.13–6.35 ml O2 l−1). Feeding success was high and mainly different groups of Copepoda were targeted, which were strongly size selected. The high dietary importance of micro-copepods during large parts of the larval phase indicates successful exploitation of this food source, which has increased in abundance during the last decade. It also explains observed best nutritional conditions at temperatures between 18 and 21°C, since these small copepods are commonly associated with warmer temperatures. Altogether, these traits enhance the species' probability to encounter suitable environments for the survival of their ELH stages, which is likely to lead to their high recruitment success in the northern Benguela ecosystem.

Sign in / Sign up

Export Citation Format

Share Document