scholarly journals Mercury contents in aquatic macrophytes from two reservoirs in the Paraíba do Sul: Guandú river system, SE Brazil

2006 ◽  
Vol 66 (1a) ◽  
pp. 101-107 ◽  
Author(s):  
M. M. Molisani ◽  
R. Rocha ◽  
W. Machado ◽  
R. C. Barreto ◽  
L. D. Lacerda
Keyword(s):  
Aquatic Macrophyte ◽  
River System ◽  
Dry Weight ◽  
Significant Negative Correlation ◽  
Pistia Stratiotes ◽  
Elodea Densa ◽  
Se Brazil ◽  
Tropical Areas ◽  
Intensive Sampling ◽  
Paraíba Do Sul River

This paper reports on a study to determine the Hg content in the five most abundant aquatic macrophyte species (Elodea densa, Sagittaria montevidensis, Salvinia auriculata, Pistia stratiotes and Eichhornia crassipes) in two artificial reservoirs flooded by water diverted from the Paraíba do Sul river, SE Brazil. The potential of these species for Hg accumulation and their role in Hg transport along the river system due to macrophyte management were evaluated. Mercury concentrations were higher in free-floating than in rooted species. Roots were also richer in Hg than were leaves. Dry weight Hg concentrations in leaves and roots from all species varied from 46-246 ng.g-1 to 37-314 ng.g-1, respectively. These values are higher than those reported for uncontaminated lakes in Brazil and in other tropical areas and similar to those reported for moderately contaminated sites. Mercury concentrations can be attributed to fluvial transport from the heavily industrialized Paraíba do Sul river basin. Intensive sampling of Pistia stratiotes from two sites in the Vigário reservoir was performed to evaluate the capacity of Hg incorporation in short periods of time. The results showed a significant negative correlation between Hg content and size class of individual plants, demonstrating the importance of juveniles, fast growing plants in absorbing Hg. The foremost impact related to Hg contents in the studied area concerns the periodic removal of macrophytes for reservoir management, followed by disposal in nearby areas. This results in the mobilization of 0.52 to 1.3 Kg of Hg per year, a significant fraction of the Hg burden present in reservoir waters. Disposal of such material may result in Hg leaching to river systems, affecting the Hg transfer throughout the basin.

scholarly journals Macroinvertebrate fauna associated with Pistia stratiotes and Nymphoides indica in subtropical lakes (south Brazil)

2007 ◽  
Vol 67 (3) ◽  
pp. 499-507 ◽  
Author(s):  
EF. Albertoni ◽  
LJ. Prellvitz ◽  
C. Palma-Silva
Keyword(s):  
Aquatic Macrophyte ◽  
Diversity Index ◽  
Mesh Size ◽  
Dry Weight ◽  
Pistia Stratiotes ◽  
Subtropical Lakes ◽  
Taxa Richness ◽  
Wiener Diversity Index ◽  
Successional Stages ◽  
Nymphoides Indica

This study was carried out at the Biguás and Polegar lakes, both small environments but at different successional stages. The main objective was to characterize the macroinvertebrate community associated to the aquatic macrophyte stand in each lake in order for this community, the environmental conditions and their water quality to interact. The samples were taken in 2003. The abiotic variables of N and P totals, the temperature, electrical conductivity, pH and dissolved oxygen, as well as the determined clorophyll a concentration were measured. Macroinvertebrates were sampled with a 500 µ mesh size net, separated under a stereomicroscope and identified at the lowest possible taxonomic level, and their densities were shown as the number of individuals per 100 g of macrophyte dry weight. The Shannon-Wiener Diversity Index (H'), Pielou evenness (J), frequency of occurrence, abundance and taxa richness were calculated for each invertebrate community. The Lago dos Biguás is undergoing a process of eutrophication and during the study presented a large Pistia stratiotes stand. The Lago Polegar is oligotrophic and had only a small Nymphoides indica bankwe. The macrophyte associated invertebrate communities in each lake were considered significantly different (p < 0.05). Sixty seven taxa were found for the Lago dos Biguás and 32 for the Lago Polegar. For both lakes, most of the taxa were considered rare, with a low dominance in a few months. The taxa with highest densities at Lago dos Biguás were Chironomidae, Daphniidae and Cyclopidae, and Oligochaeta, Chironomidae and Coenagrionidae for Lago Polegar.

Purification of Pisciculture Waters through Cultivation and Harvesting of Aquatic Biomass

1987 ◽  
Vol 19 (10) ◽  
pp. 113-121 ◽  
Author(s):  
C. Simeon ◽  
M. Silhol
Keyword(s):  
Aquatic Macrophyte ◽  
Dry Weight ◽  
Final Decision ◽  
Effluent Water ◽  
Aquatic Biomass ◽  
Growing Period ◽  
European Climate ◽  
Nuclear Plants ◽  
Economical Optimization ◽  
Water Hyacinths

The study of thermal wastes from the nuclear plants around Pierrelatte for agricultural, piscicultural, energy and environmental protection purposes resulted in the establishment of a pilot facility as early as 1976. An aquatic macrophyte pilot facility has been operational since 1983 to study the use of water hyacinths from the aspects of energy and ecology. The results obtained suggest that production yields for the 7 month growing period should exceed 60 metric tons (MT) (dry weight) per hectare in a European climate, and that such crops can feasibly be cultivated in temperate regions. The pilot facility is supplied with pisciculture effluent water, making it possible to quantify the stabilization power of the plants. Without primary decantation, with a retention time of 4 days and stabilization with water hyacinths only, the organic matter waste pond surface area required is 3.5 m2/m2 of pisciculture pond. Any primary or secondary facilities will lead to a reduction of these areas. The final decision will depend on the economical optimization of all the wastewater.

scholarly journals Genotypic resistance to brown heart incidence in swede parent lines and F1 hybrids and the influence of applied boron

2013 ◽  
Vol 153 (2) ◽  
pp. 195-204 ◽  
Author(s):  
F. FADHEL ◽  
A. J. JELLINGS ◽  
S. KENNEDY ◽  
M. P. FULLER
Keyword(s):  
Brassica Napus ◽  
Single Gene ◽  
Dry Weight ◽  
Significant Negative Correlation ◽  
F1 Hybrids ◽  
Dominant Trait ◽  
Genotypic Resistance ◽  
Resistant Varieties ◽  
Effect Of Treatment ◽  
The Uk

SUMMARYBreeding trials for swede (Brassica napus var. napobrassica) in 2000–2010 showed that 0·85 of the incidence of brown heart (BH) in the trials was associated with genotypes that are progeny of Ag31, Or13 and Me77c. In order to investigate this and the effect of treatment with boron (B), established varieties and improved parent lines carrying male sterility (ms), and their F1 hybrids (test hybrids), were grown in a field trial in the UK in 2011 and subjected to four B treatments (0·00, 1·35, 1·80 and 2·70 kg B/ha). The results confirmed that BH incidence and severity was affected by genotype but could be ameliorated by B application. Genotype Ag31 was very susceptible while Or13 and Me77c were of intermediate susceptibility and the hybrids between susceptible parents were also sensitive. Genotypes Gr19 and Ly01 were highly resistant even in the absence of B application. Hybrids between resistant and susceptible lines were highly resistant. The use of ms had no influence on BH. Resistance to BH was a dominant trait: homozygous dominant (BHBH) or heterozygous (BHbh) genotypes confer this trait, while susceptibility is recessive (bhbh). Some quantitative variation existed, suggesting that resistance was not a single gene effect. There was a significant negative correlation (r=−0·632) between root B content and the severity of BH in susceptible genotypes. Severe BH was associated with 12–21·5 μg B/g of root dry weight at zero B applied. Moderate discolouration was associated with 19·5–24·8 μg B/g recorded at moderate B applied and only Ag31 showed BH at 2·70 kg B/ha. Resistant varieties had root contents of 23 μg B/g or more while susceptible varieties required a minimum of 31 μg B/g to offset BH.

scholarly journals Population dynamics and net primary production of the aquatic macrophite Nymphaea rudgeana C. F. Mey in a lotic environment of the Itanhaém River basin (SP, Brazil)

2000 ◽  
Vol 60 (1) ◽  
pp. 83-92 ◽  
Author(s):  
A. F. M. CAMARGO ◽  
E. R. FLORENTINO
Keyword(s):  
Population Dynamics ◽  
Primary Production ◽  
Aquatic Macrophytes ◽  
Aquatic Macrophyte ◽  
Net Primary Production ◽  
Growth Period ◽  
Pistia Stratiotes ◽  
Annual Productivity ◽  
Lotic Environment ◽  
Low Levels

In this paper we evaluated the population dynamics and obtained estimates of the net primary production of the aquatic macrophyte Nymphaea rudgeana in an arm of the Itanhaém River (São Paulo State, Brazil). This species presents, in the studied area, a broad seasonal variation of biomass. As from November (13.1 g DW/m²) we observed a gradual increase of biomass that reached a maximum in February (163.1 g DW/m²). Then, the biomass decreased, maintaining low levels until a new growth period. The reduction of biomass is associated to the development of floating aquatic macrophytes (Pistia stratiotes and Salvinia molesta) and, subsequently to environmental factors (higher salinity values) that are unfavorable to their development. The net primary production of N. rudgeana was estimated from the biomass data, and the annual productivity value was estimated between 3.02 and 3.82 t/ha/year.

Limnological Features of Cedar Lake, Manitoba

1965 ◽  
Vol 22 (5) ◽  
pp. 1123-1136
Author(s):  
D. W. Webb
Keyword(s):  
Thermal Stratification ◽  
River System ◽  
Dry Weight ◽  
Total Dissolved Solids ◽  
Mean Value ◽  
Total Alkalinity ◽  
Bottom Fauna ◽  
Chemical Factors ◽  
Main Basin ◽  
Physical And Chemical

Cedar Lake, largest lake in the Saskatchewan River system, was studied from June 14 until August 31, 1962. Twenty stations, located in the main basin of the lake, were examined during six sampling periods. These stations were located along five transects, at depths of 1.5, 3, 6, and 9 m. No thermal stratification occurred and the oxygen concentration never fell below 78% of air saturation. Total alkalinity and total dissolved solids averaged above 65 and 270 ppm, respectively.The average number of bottom organisms increased with depth, with the bulk of these being made up of spheariid clams, mayflies, chironomids, and gastropods. The number of genera also increased with depth. The standing crops determined for the six sampling periods ranged from 17.7 to 33.2 lb/acre (dry weight), with a mean value of 23.4 lb/acre. Correlations between the physical and chemical factors and the distribution of bottom fauna are examined and it is felt that the bottom type is the major factor affecting the distribution and abundance of bottom organisms in Cedar Lake. On the basis of the physical and chemical criteria, Cedar Lake may be classified as eutrophic.

scholarly journals Tellurium behaviour in a major European fluvial–estuarine system (Gironde, France): fluxes, solid/liquid partitioning and bioaccumulation in wild oysters

2019 ◽  
Vol 16 (4) ◽  
pp. 229 ◽  
Author(s):  
Teba Gil-Díaz ◽  
Jörg Schäfer ◽  
Lionel Dutruch ◽  
Cécile Bossy ◽  
Frédérique Pougnet ◽  
...  
Keyword(s):  
River System ◽  
Dry Weight ◽  
Anthropogenic Sources ◽  
Critical Element ◽  
Estuarine System ◽  
Environmental Behaviour ◽  
Gironde Estuary ◽  
Estuary Mouth ◽  
Solid Liquid ◽  
Comprehensive Study

Environmental contextThe environmental behaviour of tellurium is poorly understood. We investigate the transport of tellurium in both dissolved and particulate forms from the river watershed to the Gironde Estuary, where a 30-year historical record provides insight on tellurium bioaccumulation in wild oysters. These results constitute the first comprehensive study on natural tellurium behaviour in a major fluvial-estuarine system, information essential for predictive modelling of tellurium risk assessment. AbstractTellurium (Te) is a technology critical element (TCE) with largely unknown environmental behaviour, especially in continent-ocean interface systems. The unknown behaviour results from the lack of studies in aquatic environments and from analytical challenges limiting the determination of its naturally low (ultra-trace) environmental levels. We performed a comprehensive study of Te in the Lot–Garonne–Gironde fluvial–estuarine system to better understand seasonal variations, solid/liquid partitioning (Kd), gross fluxes, estuarine dynamics, and transfer to wild oysters at the estuary mouth. A temporal record (2014–2017) of dissolved (Ted) and particulate (Tep) Te concentrations at five sites in the Lot–Garonne River system shows little differences between sites, with average ~0.9ngL−1 and ~50µgkg−1 respective concentrations. Watershed Ted and Tep follow parallel seasonal patterns, which result in constant partitioning (log10 Kd ~4.75Lkg−1), with constant annual gross dissolved fluxes (~15.0kgy−1) and variable gross particulate fluxes (from 6.50 to 140kgy−1) entering the Gironde Estuary. Estuarine reactivity in contrasting hydrological conditions (from flood to drought) suggest that grain-size effects and/or estuarine hydrological residence times strongly affect Tep behaviour. Historical records (1984–2017) of Te in wild oysters at the estuary mouth vary from 1.33 to 2.89µgkg−1 dry weight (d.w.), without any clear long-term trend. This study provides rare knowledge on Te environmental dynamics in aquatic systems, and suggests that, although no current anthropogenic sources were identified in the economically developed Lot-Garonne-Gironde fluvial-estuarine system, there is a non-negligible bioaccumulation in wild oysters at the estuary mouth.

scholarly journals Gerris spinolaeLethierry and Severin (Hemiptera: Gerridae) andBrachydeutera longipesHendel (Diptera: Ephydridae): Two Effective Insect Bioindicators to Monitor Pollution in Some Tropical Freshwater Ponds under Anthropogenic Stress

2012 ◽  
Vol 2012 ◽  
pp. 1-10
Author(s):  
Arijit Pal ◽  
Devashish Chandra Sinha ◽  
Neelkamal Rastogi
Keyword(s):  
Dissolved Oxygen ◽  
Negative Correlation ◽  
Dry Weight ◽  
Significant Negative Correlation ◽  
Positive Correlation ◽  
Freshwater Ponds ◽  
Abundance Patterns ◽  
Water Quality Variable ◽  
Free Carbon Dioxide ◽  
Tropical Freshwater

The abundance patterns of two insects,Gerris spinolaeandBrachydeutera longipes, were found to be affected by abiotic aquatic factors including free carbon dioxide, dissolved oxygen, BOD, and phosphate concentrations prevailing in four tropical freshwater ponds, three of which being anthropogenically stressed. Regression analysis between each individual-independent water quality variable and insect abundance demonstrated a significant positive correlation in each case betweenB. longipesabundance and BOD, phosphate, free CO2, and algae dry weight, while a significant negative correlation of each of these variables was found withGerris spinolaeabundance. Moreover, a significant negative correlation ofB. longipesabundance was calculated with dissolved oxygen concentration, whileG. spinolaeabundance exhibited a positive correlation with the same. Thus,G. spinolaeappears to be a pollution sensitive, effective bioindicator for healthy unpolluted ponds, whileB. longipeshas potential as a pollution-resistant insect species indicative of pollution occurrence.

UV Absorbance By Thallus Extracts of Umbilicate Lichens

1993 ◽  
Vol 25 (4) ◽  
pp. 415-422 ◽  
Author(s):  
Dianne Fahselt
Keyword(s):  
Negative Correlation ◽  
Dry Weight ◽  
Significant Negative Correlation ◽  
Enzyme Polymorphism ◽  
Uv Absorbance ◽  
Banding Patterns

AbstractEleven stands of umbilicate lichens exhibiting a range of variabilities in enzyme banding patterns were compared on the basis of the ultraviolet (UV)absorbing properties of thallus extracts. Stands of Umbilicaria veilea, which were some of the most variable enzymatically, had the lowest UV absorbancy in extracts, and stands of Lasallia papulosa, which were among the least variable enzymatically, showed more UV absorbance than others. Umbilicaria deusta, U. muhlenbergii and U. mammulata had intermediate levels of absorbance. Negative correlations (P = 005–007) were found between enzyme polymorphism and UV absorbance in the ranges 215–220, 269–271 and 304–305 nm. There was also a significant negative correlation at P = 003 between enzyme variability and thallus dry weight extractable with either ethanol or acetone.

scholarly journals Resistance in Annual Medicago spp. to Phoma medicaginis and Leptosphaerulina trifolii and Its Relationship to Induced Production of a Phytoestrogen

Plant Disease ◽  
2007 ◽  
Vol 91 (3) ◽  
pp. 239-244 ◽  
Author(s):  
Martin J. Barbetti
Keyword(s):  
Field Tests ◽  
Dry Weight ◽  
Growing Season ◽  
Significant Negative Correlation ◽  
Leaf Disease ◽  
Herbage Quality ◽  
Phoma Medicaginis ◽  
Disease Resistances ◽  
Annual Medicago

Foliar and stem diseases of annual Medicago spp. caused by Phoma medicaginis and Leptosphaerulina trifolii can not only reduce yield, but also affect herbage quality by inducing the production of the phytoestrogen coumestrol. To determine differences in host reaction to these pathogens, 33 cultivars and lines in 1993 and 10 cultivars in 1995 were evaluated in inoculated field tests. In the 1993 test, a number of genotypes with high levels of resistance to leaf and stem disease caused by P. medicaginis and to leaf disease caused by L. trifolii were identified. Genotypes with very high levels of resistance to stem disease caused by P. medicaginis were M. sphaerocarpos GRC5659.4.1 and SAD10069, M. murex GRC87.1, GRC707, and GRC708, M. truncatula Z771, and M. solerolii DZA3180.1, all of which had stem disease scores of ≤1.0 (scale 0 to 10) by the end of the growing season. The levels of coumestrol produced ranged from 114 to 1,230 ppm dry weight in stems across the genotypes, and the score for stem disease caused by P. medicaginis in the corresponding cultivars ranged from ≤0.8 to 8.9, respectively. The 1995 test confirmed the relative responses of nine cultivars (Caliph, Circle Valley, Cyprus, Harbinger AR, Zodiac, Paraggio, Santiago, Serena, and Orion) of annual Medicago spp. to leaf and stem disease caused by P. medicaginis and to stem disease caused by L. trifolii. Those with the lowest levels of coumestrol in the stems were M. solerolii DZA3180.1, M. truncatula Paraggio, and M. sphaerocarpos SAD10069, all with levels ≤130 ppm. The highest level was found in M. polymorpha SA4178 (1,230 ppm). M. littoralis Harbinger AR, Z286, Z298, and Z912, M. murex 89F16.1.1, M. orbicularis SA8460, and M. polymorpha SA4188, all had coumestrol levels of >600 ppm. For stem disease caused by P. medicaginis in particular, there was significant correlation of the level of disease with the level of coumestrol in stems at the end of the growing season. In contrast, for L. trifolii, there was significant negative correlation (leaf disease) or only a weak positive correlation (stem disease) with coumestrol in stems at the end of the growing season. Incorporation of these identified disease resistances into commercial cultivars offers a promising avenue not only as a long-term strategy for management of foliar diseases in annual Medicago spp., but also as a means of reducing phytoestrogen levels in commercial annual Medicago spp. pastures in order to minimize the adverse effects of phytoestrogens on fertility levels in sheep.

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