scholarly journals Physical and Chemical Characteristics of a Mediterranean Coastal Microenvironment: The "Salty Lake" of Aghios Nikolaos (Crete, Greece)

2013 ◽  
Vol 2 (2) ◽  
pp. 167-178
Keyword(s):  
Coastal Waters ◽  
Marine Ecosystem ◽  
Anthropogenic Pollutants ◽  
High Concentrations ◽  
Lake Waters ◽  
Physical And Chemical ◽  
The Impact ◽  
Very High ◽  
Production Of Ammonia

The present paper examines a small and deep (53 m) salty lake, as well as the adjacent harbor of Aghios Nikolaos (Crete). The survey was carried out in 1996. Physicochemical parameters indicated that the main characteristics of the system are the inflow of karstic water from underwater springs inside the lake and the permanent anoxic conditions prevailing in its deeper part, below the thermocline. Nutrient concentrations are very high throughout the water column of the lake. Ammonia is the main source of nitrogen in the summer, particularly below the thermocline, whereas nitrates have high concentrations during spring and autumn. The high levels of these nutrients in the adjacent to the lake harbor and coastal waters indicate clearly the impact of the lake to the marine ecosystem. Anthropogenic pollutants, such as aromatic hydrocarbons, show high concentrations above thermocline, at 5-10 m depths during all samplings. However no particular point source was identified. The presence of hydrocarbons contributes to ineffective oxygenation of the lake waters and facilitates the development of anoxia and the production of ammonia. The PAH concentrations at the sampling stations outside the lake are typical of marine environments, with relatively small oil-derived inputs, indicating the complex role of the system as a source and/or as a trap of PAHs.

scholarly journals Counseling on Good Water Quality for the Cultivation of Batak Fish in Toba Lake Waters

2021 ◽  
Vol 2 (1) ◽  
pp. 23-26
Author(s):  
Herna Febrianty Sianipar ◽  
Theresia Monika Siahaan ◽  
Apriani Sijabat
Keyword(s):  
Carbon Dioxide ◽  
Water Quality ◽  
Dissolved Oxygen ◽  
Fish Farming ◽  
Chemical Parameters ◽  
Measuring Devices ◽  
Physical And Chemical Parameters ◽  
Lake Waters ◽  
Physical And Chemical ◽  
Very High

This service aims to provide information about the value of good water quality and demonstrate directly the tools used to measure it which aim to cultivate Batak fish based on biological, physical and chemical parameters such as temperature, dissolved oxygen, carbon dioxide, pH, and provide information on the names of measuring devices. . This service has been carried out in Gorat Village, Toba Samosir Regency with the method of counseling and material discussion (exposure and question and answer), as well as the practice of measuring water quality externally and analyzing the results of its value. The results of the counseling show that many fish farmers do not understand the value of good water quality for batak fish cultivation and not many know the equipment that can be used to check water quality. From this counseling, it can be seen that the interest of fish farmers and the community is very high, and they become more aware of the value of good water quality for fish farming and know the equipment. Abstrak Pengabdian ini bertujuan untuk memberikan penyuluhan tentang nilai kualitas air yang baik dan mendemonstrasikan langsung alat yang digunakan mengukurnya yang bertujuan untuk membudidayakan ikan batak berdasarkan parameter biologi, fisika dan kimia seperti suhu, oksigen terlarut, karbondioksida, pH, serta memberikan informasi nama alat-alat pengukurnya. Pengabdian ini telah dilakukan di Desa Gorat, Kabupaten Toba Samosir dengan metode penyuluhan dan diskusi materi (paparan dan tanya jawab), serta praktek pengukuran kualitas air secara eksitu dan menganalisis hasil nilainya. Hasil penyuluhan menunjukan bahwa banyaknya petani ikan yang belum paham tentang nilai kualitas air yang baik untuk budidaya ikan batak serta belum banyak yang mengetahui peralatan yang dapat digunakan untuk memeriksa kualitas air. Dari penyuluhan ini terlihat animo petani ikan dan masyarakat sangat tinggi, dan mereka menjadi lebih paham tentang nilai kualitas air yang baik untuk budidaya ikan serta mengetahui peralatannya.

scholarly journals Glacial meltwater and primary production are drivers of strong CO<sub>2</sub> uptake in fjord and coastal waters adjacent to the Greenland Ice Sheet

2015 ◽  
Vol 12 (8) ◽  
pp. 2347-2363 ◽  
Author(s):  
L. Meire ◽  
D. H. Søgaard ◽  
J. Mortensen ◽  
F. J. R. Meysman ◽  
K. Soetaert ◽  
...  
Keyword(s):  
Primary Production ◽  
Coastal Waters ◽  
Ice Sheet ◽  
Chemical Properties ◽  
Greenland Ice Sheet ◽  
Co2 Uptake ◽  
Glacial Meltwater ◽  
Continental Shelves ◽  
Physical And Chemical ◽  
The Impact

Abstract. The Greenland Ice Sheet releases large amounts of freshwater, which strongly influences the physical and chemical properties of the adjacent fjord systems and continental shelves. Glacial meltwater input is predicted to strongly increase in the future, but the impact of meltwater on the carbonate dynamics of these productive coastal systems remains largely unquantified. Here we present seasonal observations of the carbonate system over the year 2013 in the surface waters of a west Greenland fjord (Godthåbsfjord) influenced by tidewater outlet glaciers. Our data reveal that the surface layer of the entire fjord and adjacent continental shelf are undersaturated in CO2 throughout the year. The average annual CO2 uptake within the fjord is estimated to be 65 g C m−2 yr−1, indicating that the fjord system is a strong sink for CO2. The largest CO2 uptake occurs in the inner fjord near to the Greenland Ice Sheet and high glacial meltwater input during the summer months correlates strongly with low pCO2 values. This strong CO2 uptake can be explained by the thermodynamic effect on the surface water pCO2 resulting from the mixing of fresh glacial meltwater and ambient saline fjord water, which results in a CO2 uptake of 1.8 mg C kg−1 of glacial ice melted. We estimated that 28% of the CO2 uptake can be attributed to the input of glacial meltwater, while the remaining part is due to high primary production. Our findings imply that glacial melt\\-water is an important driver for undersaturation in CO2 in fjord and coastal waters adjacent to large ice sheets.

scholarly journals Accumulation of malto-oligosaccharides in the syncytiotrophoblastic cells of first-trimester human placentas

1981 ◽  
Vol 200 (1) ◽  
pp. 93-98 ◽  
Author(s):  
S J Fisher ◽  
R A Laine
Keyword(s):  
Gel Filtration ◽  
First Trimester ◽  
Structural Elements ◽  
Trophoblastic Cells ◽  
Highly Active ◽  
A Cell ◽  
Liver Homogenates ◽  
High Concentrations ◽  
Very High

A cell-surface microvillar fraction that was isolated from the syncytiotrophoblastic cells of first-trimester human placentas was found to contain very high concentrations (890 +/- 32 microgram of hexose/mg of protein) of a class of low-molecular-weight oligosaccharides that were comprised entirely of glucose. T.l.c. and gel filtration showed that the saccharides contained from one to six glucose residues. The structures of the most prominent members of the series, a tetra- and a tri-saccharide, were determined. The anomeric configuration of the glucose residues was alpha, and methylation linkage analysis gave terminal and 4-linked hexose residues. These malto-oligosaccharides contained one reducing terminus per molecule, indicating that they were free and not bound to other structural elements of the cells. Within the placenta they appeared to be concentrated in the first-trimester trophoblastic cells, since crude membrane and particulate fractions isolated from either term trophoblastic cells or cultured placental fibroblasts did not contain detectable amounts of glucose oligomers. This series of oligosaccharides was similar to the products that are formed when glycogen is degraded by alpha-amylase in liver homogenates and may be indicative of a similar, highly active enzymic reaction closely associated with the brush border of the syncytiotrophoblastic cells of the first-trimester human placenta. Although the role of these oligosaccharides remains obscure they are probably involved in foetal metabolism.

scholarly journals A practical approach to lake water density from electrical conductivity and temperature

2016 ◽  
Vol 20 (7) ◽  
pp. 2975-2986 ◽  
Author(s):  
Santiago Moreira ◽  
Martin Schultze ◽  
Karsten Rahn ◽  
Bertram Boehrer
Keyword(s):  
Electrical Conductivity ◽  
Common Procedure ◽  
New Approach ◽  
Circulation Patterns ◽  
Lakes And Reservoirs ◽  
High Concentrations ◽  
Lake Waters ◽  
Very High ◽  
Limited Accuracy ◽  
Better Than

Abstract. Density calculations are essential to study stratification, circulation patterns, internal wave formation and other aspects of hydrodynamics in lakes and reservoirs. Currently, the most common procedure is the use of CTD (conductivity, temperature and depth) profilers and the conversion of measurements of temperature and electrical conductivity into density. In limnic waters, such approaches are of limited accuracy if they do not consider lake-specific composition of solutes, as we show. A new approach is presented to correlate density and electrical conductivity, using only two specific coefficients based on the composition of solutes. First, it is necessary to evaluate the lake-specific coefficients connecting electrical conductivity with density. Once these coefficients have been obtained, density can easily be calculated based on CTD data. The new method has been tested against measured values and the most common equations used in the calculation of density in limnic and ocean conditions. The results show that our new approach can reproduce the density contribution of solutes with a relative error of less than 10 % in lake waters from very low to very high concentrations as well as in lakes of very particular water chemistry, which is better than all commonly implemented density calculations in lakes. Finally, a web link is provided for downloading the corresponding density calculator.

scholarly journals Geochemical barriers as structural components of the geochemical systems evolution

2019 ◽  
Vol 98 ◽  
pp. 01026
Author(s):  
Aleksandr Khaustov ◽  
Margarita Redina
Keyword(s):  
Chemical Elements ◽  
Point Of View ◽  
Molecular Structures ◽  
Structural Components ◽  
Geochemical Barriers ◽  
Distribution Of Elements ◽  
Linear Thermodynamics ◽  
Physical And Chemical ◽  
The Impact

The term “geochemical barrier” (GCB) has been widely used in the Russian geochemical literature as a key concept of the distribution of elements and substances theory (incl. pollutions)although in the world research practice this term is not particularly represented. The assessment of the functional role of the geochemical barriers in relation to the properties and evolution of the geochemical systems (GCS)is demonstrated.The foundations of Haken synergy, the foundations of self-organization of systems and non-equilibrium (non-linear) thermodynamics of I. Prigogine and his school are used as a methodological framework. From the authors’ point of view, GCB are considered as self-organizing components of GCS, in which physical and chemical processes are activated, leading to the transformation of atomic and molecular structures, chemical associations and individual chemical elements under the impact of active media (processes). They can be the defining phenomenon of the emergence and evolution of GCS. The concept of geochemical barriers is the foundation for technologies that are actively implemented for cleaning and protecting soils, groundwater and surface water, and the geological environment in general.

scholarly journals Dentistry in the post covid-19 world- are we prepared?

2020 ◽  
Vol 04 (4) ◽  
pp. 01-08
Author(s):  
Vrushali Abhyankar
Keyword(s):  
Exposure Risk ◽  
High Exposure ◽  
Dental Procedures ◽  
Close Proximity ◽  
Dental Profession ◽  
Auxiliary Personnel ◽  
The Impact ◽  
Very High ◽  
Dental Professionals

Background: Covid -19 pandemic has affected dental profession tremendously and has placed dentists and dental professionals in the very high exposure risk jobs. Practicing dentistry requires the provider to be in close proximity of the patients and their oral cavity. Many dental procedures tend to generate aerosols owing to the use of an air rotor or highspeed handpiece. The impact of Covid –19 on dentistry, like all other professions is ever evolving and newer guidelines are published almost every day. The authors also examine the ethical, psychological and financial implications of this pandemic to the dental professionals as well as patients. The important role of organized dentistry is highlighted in facilitating change to adapt to the new norm and implement the safer practice guidelines. Conclusions: The authors conclude that significant changes need to be undertaken to protect patients, dental professionals, auxiliary personnel.

scholarly journals History of the museums, the mediators and scientific education

2005 ◽  
Vol 04 (04) ◽  
pp. C02 ◽  
Author(s):  
Brigitte Zana
Keyword(s):  
Main Topic ◽  
Scientific Education ◽  
The Public ◽  
Short Overview ◽  
Technical Culture ◽  
History Of ◽  
Curiosity Cabinets ◽  
The Impact ◽  
Very High

Before analysing the role of the mediators in relation to scientific education, I deem it important to provide a short overview on how scientific museums evolved from the early curiosity cabinets to the modern web cast. Although the term “museum” is no longer adapted to the new structures employed for the diffusion of scientific and technical culture, the evolution of the means of presentation has indeed led to several forms of human mediation. This is of course the main topic we are going to take into consideration today, as it is an important element for the impact our exhibitions may have on the public. Decisions and choices vary from structure to structure for reasons that are sometimes justifiable but that are more often than not economic in nature, since wages, which are in any case very high no matter which country plays host, come to bear heavily especially on the budget of small and medium-sized structures.

scholarly journals Time Variability Patterns of Eutrophication Indicators in the Bay of Algeciras (South Spain)

Water ◽  
2018 ◽  
Vol 10 (7) ◽  
pp. 938
Author(s):  
Jesús Mercado ◽  
Pablo León ◽  
Soluna Salles ◽  
Dolores Cortés ◽  
Lidia Yebra ◽  
...  
Keyword(s):  
Chlorophyll A ◽  
Inorganic Nitrogen ◽  
Principal Component ◽  
Time Variability ◽  
Nutrient Loads ◽  
Vertical Variation ◽  
High Concentrations ◽  
Upwelling Intensity ◽  
Physical And Chemical ◽  
The Impact

In the Bay of Algeciras (BA), intensive urban and industrial activityis underway, which is potentially responsible for the release of significant quantities of nutrients. However, the assessment of the impact of these discharges is complex. Nutrient concentration in the surface layer is per se strongly variable due to the variability associated with the upwelling of nutrient-enriched deep Mediterranean water (MW), which in turn is regulated by atmospheric forcing. The aim of this study is to determine the effects of changes in the upwelling intensity on the load of nitrate and phosphate in the BA and to appraise their impact on chlorophyll a variability. Based on this analysis, the possible influence of the nutrients released from land-based sources is indirectly inferred. Data and samples collected during nine research cruises carried out in different seasonal cycle periods between 2010 and 2015 in the BA were analysed. The vertical variation of temperature and salinity indicates that the MW upwelling was favoured in spring, as occurred in other coastal areas of the northern Alboran Sea. However, principal component analysis conducted on physical and chemical data reveals that shifts in nutrients and chlorophyll a in the euphotic layer are poorly explained by changes in the upwelling intensity. Furthermore, during some of these research surveys (particularly in summer), chlorophyll a concentrations were higher in the BA as compared to a nearby coastal area also affected by MW upwelling. Scarce information about land-based pollution sources precludes quantitative analysis of the impact of nutrient loads on water quality; however, the available data suggest that the main source of allochthanous inorganic nitrogen over the period 2010–2015 in the BA was nitrate. Therefore, it is reasonable to hypothesize that the high concentrations of nitrate and chlorophyll a in BA in summer are a consequence of those discharges. Our study highlights the need of more exhaustive inventories of sewage and river discharges to adequately rate their impact in the BA.

scholarly journals Changes in Human Erythrocyte Exposed to Organophosphate Flame Retardants: Tris(2-chloroethyl) Phosphate and Tris(1-chloro-2-propyl) Phosphate

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3675
Author(s):  
Bożena Bukowska
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Flame Retardants ◽  
Morphological Changes ◽  
Redox Balance ◽  
Published Data ◽  
Human Red Blood Cells ◽  
High Concentrations ◽  
The Impact ◽  
Very High

Tris(2-chloroethyl) phosphate (TCEP) and tris(1-chloro-2-propyl) phosphate (TCPP) are the main representatives of organophosphate flame retardants (OPFRs). The exposure of humans to OPFRs present in air, water, and food leads to their occurrence in the circulation. Thus far, no report has been published about the influence of these retardants on non-nucleated cells like mature erythrocytes. Therefore, the impact of TCEP and TCPP (in concentrations determined in human blood as well as potentially present in the human body after intoxication) on human erythrocytes was evaluated. In this study, the effect of TCEP and TCPP on the levels of methemoglobin, reduced glutathione (GHS), and reactive oxygen species (ROS), as well as the activity of antioxidative enzymes, was assessed. Moreover, morphological, hemolytic, and apoptotic alterations in red blood cells were examined. Erythrocytes were incubated for 24 h with retardants in concentrations ranging from 0.001 to 1000 μg/mL. This study has revealed that the tested flame retardants only in very high concentrations disturbed redox balance; increased ROS and methemoglobin levels; and induced morphological changes, hemolysis, and eryptosis in the studied cells. The tested compounds have not changed the activity of the antioxidative system in erythrocytes. TCPP exhibited a stronger oxidative, eryptotic, and hemolytic potential than TCEP in human red blood cells. Comparison of these findings with hitherto published data confirms a much lower toxicity of OPFRs in comparison with brominated flame retardants.

scholarly journals Impact of Biocorrosion on the Durability of Etics and Empirical Findings About the Periodocity of Maintenance

2013 ◽  
Vol 21 (2) ◽  
pp. 21-28
Author(s):  
Naďa Antošová
Keyword(s):  
Building Materials ◽  
Composite System ◽  
Chemical Processes ◽  
Biological Factors ◽  
Wide Range ◽  
Living Organisms ◽  
Physical And Chemical ◽  
The Impact ◽  
Complete Collapse

Abstract Generally, the role of living organisms (especially bacteria, cyanophytes, algae and fungi) in the physical and chemical processes of the biocorrosion of an external thermal insulation composite system (ETICS) is underestimated. These organisms are the ones that are responsible for a wide range of changes in or "diseases" of building materials and constructions, including damage to a building´s appearance or the destruction and complete collapse of the characteristics and requirements of materials and the ETICS construction. The following article concerns the impact of biological factors on the durability of ETICS. It shows the importance of and necessity to maintain it, and the method and periodicity of the maintenance.

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