scholarly journals The role of biotic and abiotic components of the aquatic ecosystem in the formation of ecological trouble of Tsimlyansk and Manych reservoirs

2019 ◽  
Vol 46 (5) ◽  
pp. 544-554
Author(s):  
A. M. Nikanorov ◽  
T. A. Khoruzhaya
Keyword(s):  
Aquatic Ecosystem ◽  
Aquatic Ecosystems ◽  
Environmental Disaster ◽  
State Of Emergency ◽  
Chemical Indicators ◽  
Physico Chemical ◽  
State Of Water ◽  
Abiotic Component

The relative importance of indicators of biotic and abiotic components of aquatic ecosystems of Tsimlyansky and Manych (Proletarian and Veselovsky) reservoirs is investigated in the process of formation of States of ecological trouble: “environmental stress, environmental emergency and ecological disaster”, which are provided by a number of existing normative- methodological documents. For this purpose, the shares of indicators as a percentage of their total number in the dynamics of negative changes in aquatic ecosystems were compared on the basis of long-term monitoring information of Roshydromet and data of own expeditionary studies in reservoirs on hydrobiological, toxicological and physico-chemical indicators. It is established that the role of the biotic component increases with the deterioration of the aquatic ecosystem of the Tsimlyansk reservoir, on the contrary, decreases in Manych. The role of the abiotic component is great and similar in all reservoirs; it increases already in a state of emergency environmental situation, but in an environmental disaster is somewhat reduced. It is concluded that the proposed new approach to the analysis of the role of biotic and abiotic components in the development of negative changes in the ecosystem opens up new opportunities in the study of the water quality formation and the state of water bodies.

scholarly journals ToxigenicVibrio choleraeevolution and establishment of reservoirs in aquatic ecosystems

2020 ◽  
Vol 117 (14) ◽  
pp. 7897-7904 ◽  
Author(s):  
Carla Mavian ◽  
Taylor K. Paisie ◽  
Meer T. Alam ◽  
Cameron Browne ◽  
Valery Madsen Beau De Rochars ◽  
...  
Keyword(s):  
Aquatic Ecosystems ◽  
Indian Subcontinent ◽  
Population Bottlenecks ◽  
Direct Transmission ◽  
Term Survival ◽  
Bacterial Transmission ◽  
Transmission Pathways ◽  
Robust Evidence

The spread of cholera in the midst of an epidemic is largely driven by direct transmission from person to person, although it is well-recognized thatVibrio choleraeis also capable of growth and long-term survival in aquatic ecosystems. While prior studies have shown that aquatic reservoirs are important in the persistence of the disease on the Indian subcontinent, an epidemiological view postulating that locally evolving environmentalV. choleraecontributes to outbreaks outside Asia remains debated. The single-source introduction of toxigenicV. choleraeO1 in Haiti, one of the largest outbreaks occurring this century, with 812,586 suspected cases and 9,606 deaths reported through July 2018, provided a unique opportunity to evaluate the role of aquatic reservoirs and assess bacterial transmission dynamics across environmental boundaries. To this end, we investigated the phylogeography of both clinical and aquatic toxigenicV. choleraeO1 isolates and show robust evidence of the establishment of aquatic reservoirs as well as ongoing evolution ofV. choleraeisolates from aquatic sites. Novel environmental lineages emerged from sequential population bottlenecks, carrying mutations potentially involved in adaptation to the aquatic ecosystem. Based on such empirical data, we developed a mixed-transmission dynamic model ofV. cholerae, where aquatic reservoirs actively contribute to genetic diversification and epidemic emergence, which underscores the complexity of transmission pathways in epidemics and endemic settings and the need for long-term investments in cholera control at both human and environmental levels.

Dynamics of seepage mobile inventory in forest and agricultural soils - Results from a comparative multi-year lysimeter study

2020 ◽  
Author(s):  
Katharina Lehmann ◽  
Robert Lehmann ◽  
Kai Uwe Totsche
Keyword(s):  
Land Use ◽  
Agricultural Soils ◽  
Field Studies ◽  
Critical Zone ◽  
Soil Monitoring ◽  
Event Scale ◽  
Weather Events ◽  
Physico Chemical

<p>The mobile inventory in soil seepage is of fundamental importance for soil development and for functioning of subsurface ecosystem compartments. The mobile inventory may encompass inorganic, organo-mineral and organics, dissolved and colloidal, but also particulate matter and microbiota. Still unknown are the conditions and factors that trigger the release and export of seepage-contained mobile matter within soil, and its translocation through the subsurface of the critical zone. Long-term and high-resolution field studies that includes the mobile particulate inventory are essentially lacking. To overcome this knowledge gap, we established long-term soil monitoring plots in the Hainich Critical Zone Exploratory (HCZE; NW-Thuringia, central Germany). Soil seepage from 22 tension-supported lysimeters in topsoil and subsoil, covering different land use (forest, pasture, cropland) in the topographic recharge area of the HCZE, was collected and analyzed by a variety of analytical methods (physico-/chemical and spectroscopic) on a regular (biweekly) and event-scale cycle. With our study we proved that substances up to a size of 50 µm are mobile in the soils. The material spectra comprised minerals, mineral-organic particulates, diverse bioparticles and biotic detritus. Atmospheric forcing was found to be the major factor triggering the translocation of the mobile inventory. Especially episodic infiltration events during hydrological winter seasons (e.g. snow melts) with high seepage volume influences seepage hydrochemistry (e.g. pH, EC) and is important for transport of mobile matter to deeper compartments. Seasonal events cause mobilization of significant amounts of OC. On average, 21% of the total OC of the seepage was particulate (>0.45 µm). Furthermore, our results suggest that the formation environment and the geopedological setting (soil group, parent rock, land use) are controlling factors for the composition and the amount of soil-born mobile inventory. Our study provides evidence for the importance of the mobile inventory fraction >0,45 µm for soil element dynamics and budgets and highlights the role of weather events on soil and subsoil development and subsurface ecosystem functioning.</p>

scholarly journals DIVERSITY AND SIMILARITY AMONG CYANOBACTERIA ASSEMBLAGES FROM SELECTED AQUATIC ECOSYSTEMS IN SARAWAK USING β –INDICES

2016 ◽  
Vol 1 (1) ◽  
pp. 28-37
Author(s):  
Mohd Nasarudin Harith ◽  
Ruhana Hassan
Keyword(s):  
Aquatic Ecosystem ◽  
Aquatic Ecosystems ◽  
Chemical Properties ◽  
Artificial Lake ◽  
Environmental Characteristics ◽  
Β Diversity ◽  
Physico Chemical ◽  
Wide Range ◽  
Aquaculture Ponds

A study was carried out to evaluate the diversity and similarity of cyanobacterial populations in selected Sarawak aquatic ecosystem using β-indices. Eight stations including aquaculture ponds, cage cultures, waterfall and artificial lake located in Serian, Bau and Batang Ai areas were selected. A total of 43 species belonging to 30 genera of cyanobacteria were recorded. The most distributed pattern among all sampling stations belongs to the genera Chroococcus, Lyngbya, Nostoc and Oscillatoria. The highest β diversity values were found among non-contiguous stations. Besides, no identical or totally different cyanobacteria diversity values were obtained among those non-contiguous stations. The highest β diversity value (0.84) was found among stations with contrasting environmental characteristics. The wide range of β-diversity and similarity suggested that different locations and types of aquatic ecosystems may have variations in physico-chemical properties of the water and eventually lead to the different composition of cyanobacteria.

INVESTIGATING THE POSSIBILITY OF USING THE NATURAL BITUMEN OF GILSONITE TYPE FOR THE PRODUCTION OF ROAD BITUMEN

2019 ◽  
pp. 37-41
Author(s):  
Ivan Kopynets ◽  
Oleksii Sokolov ◽  
Оksana Sokolova ◽  
Alina Yunak
Keyword(s):  
Asphalt Concrete ◽  
Softening Point ◽  
Heavy Traffic ◽  
Petroleum Products ◽  
Natural Bitumen ◽  
Chemical Indicators ◽  
High Adhesion ◽  
Physico Chemical ◽  
Adverse Weather

The heavy traffic combined with the adverse weather and climate factors which are characteristic for most of the year, makes high demands for asphalt concrete. The quality of asphalt concrete is largely determined by the properties of bitumen which plays the role of a binder which provides the formation of a monolithic composite road-building material from separate mineral grains. Compound bitumen obtained by mixing the peroxidized bitumen with tar have the best ratio of all physico-chemical indicators, it is also possible the option to compound residual bitumen with oxidized. Oxidized bitumen obtained by the oxidation of tar or a mixture of tar with other petroleum products is characterized by low cohesive strength, poor adhesion and considerable aging. The use of natural bitumen of gilsonite type is the most common method to improve the properties of bitumen. When introducing into the bitumen of this natural bitumen, its penetration at a temperature of 25° C is reduced, as well as the softening point is increased. In fact, the nature of the change in the properties of bitumen during introduction of natural bitumen is the same as during its oxidation. That is, natural bitumen can be used to produce road bitumen by compounding it with tar. This paper presents the results of bitumen research obtained by combining tar with natural bitumen of gilsonite type. The production of bitumen by combining tar with natural bitumen of gilsonite type allows obtaining different grades of road bitumen by changing the content of natural bitumen. Bitumen obtained by this technology is more heat- and crack-resistant, have high adhesion to the aggregates and are not subjected to the technological aging. This bitumen has a higher softening point and a lower Fraass breaking point and therefore a higher plasticity interval. Keywords: bitumen, production, equiviscous temperatures, natural bitumen, mixing.

scholarly journals Diverse role of Macrophytes in aquatic ecosystems: A brief review

2019 ◽  
Vol 19 ◽  
pp. 40-48
Author(s):  
Mitu De ◽  
◽  
Chayanika Roy ◽  
Suchismita Medda ◽  
Sulagna Roy ◽  
...  
Keyword(s):  
Aquatic Ecosystem ◽  
Aquatic Ecosystems ◽  
Aquatic Macrophytes ◽  
Food Source ◽  
Aquatic Vegetation ◽  
Submerged Macrophytes ◽  
Freshwater Ecosystems ◽  
Aquatic Life ◽  
Aquatic Flora

The aquatic ecosystem is composed of aquatic flora and fauna which interact together in maintaining the aquatic ecosystem. Aquatic macrophytes are macroscopic forms of aquatic vegetation, including macro algae, mosses, ferns and angiosperms found in aquatic habitat. Macrophytes of freshwater ecosystems have diverse roles to play in the structure and functioning of these aquatic ecosystems. The depth, density, diversity and types of macrophytes present in a system are indicators of water body health. Aquatic vegetation can influence the water quality too. Macrophytes are considered as an important component of the aquatic ecosystem as the habitat and food source for aquatic life. Of all the biological treatments for controlling eutrophication, submerged macrophytes, has been recognized as being the most effective. This paper is a brief review of the diverse role of macrophytes in an aquatic ecosystem.

scholarly journals ASSESSMENT OF THE ROLE OF STORAGE OF LOW-RATED COTTON SEEDS ON ITS PHYSICO-CHEMICAL INDICATORS

2021 ◽  
Vol 82 (1-2) ◽  
Author(s):  
Azimjon Akhmedov ◽  
Saidakbar Abdurakhimov ◽  
Gulbahor Suvanova ◽  
Javlonbek Giyasov
Keyword(s):  
Chemical Indicators ◽  
Physico Chemical ◽  
Cotton Seeds

Activation of cytochrome c to a peroxidase compound I-type intermediate by H2O2: relevance to redox signalling in apoptosis

2004 ◽  
Vol 71 ◽  
pp. 97-106 ◽  
Author(s):  
Mark Burkitt ◽  
Clare Jones ◽  
Andrew Lawrence ◽  
Peter Wardman
Keyword(s):  
Cytochrome C ◽  
Hydroxyl Radical ◽  
Redox Regulation ◽  
Chemotherapeutic Agents ◽  
Tyrosyl Radical ◽  
Compound I ◽  
Definitive Evidence ◽  
Enhanced Production ◽  
Physico Chemical

The release of cytochrome c from mitochondria during apoptosis results in the enhanced production of superoxide radicals, which are converted to H2O2 by Mn-superoxide dismutase. We have been concerned with the role of cytochrome c/H2O2 in the induction of oxidative stress during apoptosis. Our initial studies showed that cytochrome c is a potent catalyst of 2′,7′-dichlorofluorescin oxidation, thereby explaining the increased rate of production of the fluorophore 2′,7′-dichlorofluorescein in apoptotic cells. Although it has been speculated that the oxidizing species may be a ferryl-haem intermediate, no definitive evidence for the formation of such a species has been reported. Alternatively, it is possible that the hydroxyl radical may be generated, as seen in the reaction of certain iron chelates with H2O2. By examining the effects of radical scavengers on 2′,7′-dichlorofluorescin oxidation by cytochrome c/H2O2, together with complementary EPR studies, we have demonstrated that the hydroxyl radical is not generated. Our findings point, instead, to the formation of a peroxidase compound I species, with one oxidizing equivalent present as an oxo-ferryl haem intermediate and the other as the tyrosyl radical identified by Barr and colleagues [Barr, Gunther, Deterding, Tomer and Mason (1996) J. Biol. Chem. 271, 15498-15503]. Studies with spin traps indicated that the oxo-ferryl haem is the active oxidant. These findings provide a physico-chemical basis for the redox changes that occur during apoptosis. Excessive changes (possibly catalysed by cytochrome c) may have implications for the redox regulation of cell death, including the sensitivity of tumour cells to chemotherapeutic agents.

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