The effect of winter drainage on reservoir benthic fauna

1969 ◽  
Vol 47 (4) ◽  
pp. 589-595 ◽  
Author(s):  
C. G. Paterson ◽  
C. H. Fernando
Keyword(s):  
Indirect Evidence ◽  
Benthic Fauna ◽  
Atmospheric Conditions ◽  
Southern Ontario ◽  
Probability Of Survival ◽  
Short Period ◽  
Benthic Environment ◽  
Laurel Creek ◽  
Caddis Fly ◽  
Chironomid Fauna

Winter drainage of Laurel Creek Reservoir in southern Ontario exposed the benthic environment to atmospheric conditions for between 168 and 176 days. During the first 50 days, which had above-freezing temperatures, much of the fauna was destroyed. In the next 100 days the substrate became frozen to depths greater than 20 cm. Freezing of the substrate resulted in the loss of the oligochaetes, nematodes, and oribatoid mites as well as a large percentage of the chironomid fauna. Small numbers of the caddis fly, Agraylea multipunctata; the chironomid Cricotopus trifasciatus; and the molluscs Planorbula jenksii and Lymnaea palustris were found to survive the period of freezing and the subsequent short period of thawing before the refilling of the reservoir. Indirect evidence suggests the survival of small numbers of certain species of chironomids not found in the samples. Glyplotendipes barbipes showed the highest survival under the conditions of exposure, as the population immediately after refilling was between 12.5 and 46.4% of that found before drainage of the reservoir. The fauna did not actively move deeper into the substrate as freezing progressed although the probability of survival was greater at the deeper levels. A. multipunctata, C. trifasciatus, and G. barbipes have been found able to pupate and emerge after survival in the exposed substrate.

Benthic Fauna Colonization of a New Reservoir with Particular Reference to the Chironomidae

1970 ◽  
Vol 27 (2) ◽  
pp. 213-232 ◽  
Author(s):  
C. G. Paterson ◽  
C. H. Fernando
Keyword(s):  
Dominant Species ◽  
Dominance Hierarchy ◽  
Benthic Fauna ◽  
Partial Loss ◽  
Organic Debris ◽  
Wide Range ◽  
The Rich ◽  
Laurel Creek ◽  
Chironomid Fauna ◽  
New Reservoir

At the time of first filling of Laurel Creek Reservoir in the spring of 1967 the benthic fauna consisted of submerged terrestrial organisms and obligate and facultative rheophilic species. Two months after initial filling substantial populations of colonizing limnophilic species developed in the habitat whereas the terrestrial and obligate rheophilic components were lost. By the 4th month the fauna was dominated by euryoxybiontic limnophiles and by facultative species. In the period immediately prior to reservoir drainage in the autumn of 1967 the population densities of the euryoxybiontic chironomids declined whereas polyoxybiontic species continued to increase in abundance. These changes in the dominance hierarchy of the chironomid fauna were associated with the partial loss of the rich deposits of organic debris by siltation and decomposition. Survival of winter drainage of the reservoir by many limnophilic species produced an appreciably different pattern of colonization when the reservoir refilled in 1968. During the second summer of the reservoir's existence most euryoxybiontic chironomids further declined in abundance and were replaced by polyoxybiontic forms as the dominant species. The facultative species originally derived from the creek fauna are adapted to a wide range of environmental conditions and the modifications of the reservoir habitat with time had little effect on their abundance.

The effect of hydrodynamic cavitation on performance of the alkaline aluminosilicate coatings for metal structures

2018 ◽  
Vol 2 (1) ◽  
Author(s):  
Sergii GUZII 1 ◽  
Pavel KRIVENKO 1
Keyword(s):  
Protective Coatings ◽  
Optimal Parameter ◽  
Metal Substrate ◽  
Hydrodynamic Cavitation ◽  
Major Constituent ◽  
Atmospheric Conditions ◽  
Hydration Products ◽  
Metal Structures ◽  
Coated Metal ◽  
Short Period

Load-bearing metal structures working in atmospheric conditions are exposed to corrosion. Known-in-the art paint-and-lacquer protective coatings can provide protection of metal for rather short period of time (5…10 years). These structures can be effectively protected by more advanced coatings of new generation, namely: alkaline aluminosilicate binder-based coatings of barrier type. These binders differ from the known-in-the-art binding materials by formation in their hydration products of zeolite-like minerals and feldspathoids. The paper discusses principles laid down in formulating the binder composition in the (хК, уNa)2OAl2O3nSiO2mH2O system, target synthesis of hydration products of the binder matrix under influence of dynamic of the binder matrix in cavitation, optimal parameter order to synthesis of cavitation treatment aimed at nanostructuring of zeolite-like and hydromica phases after solidification. These coatings exhibit high corrosion resistance, high adhesion to metal substrate and durability results of restoration works that had been carried out in December 2010 of the Big Bell Tower of the Kiev Petchersk Lavra in order to protect corroded metal surfaces by applying the aluminosilicate binder-based coatings, the major constituent (binder) of which was represented by (0.72Na2O+0.28K2O)1.5Al2O3(4.56)SiO217.5H2O are discussed in details. In 2016, after 6 years of service in high humidity conditions and other aggressive exposures, the coated metal structures were examined and no sign of corrosion of metal substrate and damage of the applied coating was found.

scholarly journals ACCURACY IMPROVEMENT OF TROPOSPHERIC DELAY CORRECTION MODELS IN SPACE GEODETIC DATA. CASE STUDY: EGYPT

2014 ◽  
Vol 40 (4) ◽  
pp. 148-155
Author(s):  
Sobhy Abdel Monem Younes ◽  
Hafez Abbas Afify
Keyword(s):  
Elevation Angle ◽  
Tropospheric Delay ◽  
Limiting Factor ◽  
Data Sets ◽  
Atmospheric Conditions ◽  
New Model ◽  
External Data ◽  
Short Period ◽  
The Mean ◽  
Height Component

The tropospheric delay still remains a limiting factor to the accuracy of space based positioning techniques. The estimation of station positioning, especially height component, which is particularly important for more applications is susceptible to errors in modeling the tropospheric delay due to correlations between the station positioning and residual troposphere delay parameters. As the demand on positioning accuracy and precision has increased, it has begun a necessary of relaying on large external data sets, rather than relatively simple models for treating the tropospheric delay. This method has been possible by advances made in numerical weather models which provide accurate representations of global atmospheric conditions and by advances in computing speed which allow us to perform a large number of computations over a short period of time. The purpose of this work is to develop a new model for estimating the tropospheric delay and then assess the benefits of applying this model at various geographic atmospheric conditions of Egypt. By comparing new model with some common models such as Saastamoinen model, Hopfield model, Niell-MF, Black & Eisner-MF, UNB3 model and Vienna-MF, the results show that, new model for estimation tropospheric delay has an acceptable level of accuracy in describing the dry tropospheric delay in Egypt as it agrees closely with the numerical integration based model. The mean accuracy of this new model has been assessed to be about 9.64 mm with rms 11 mm at an elevation angle of 30° and for an elevation angle of 5°, the mean accuracy is about 83.23 mm with rms 96.42 mm for atmospheric conditions of Egypt.

scholarly journals CAN SMOS SOIL MOISTURE DRY-DOWNS BE USEFUL TO DETECT FLOOD CONDITIONS OVER THE ARGENTINEAN PAMPAS PLAINS?

2020 ◽  
Vol XLII-3/W12-2020 ◽  
pp. 279-283
Author(s):  
L. Cappelletti ◽  
A. Sörensson ◽  
R. Ruscica ◽  
M. M. Salvia ◽  
E. Jobbágy ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Time Scales ◽  
Capillary Rise ◽  
Precipitation Anomaly ◽  
Water Dynamics ◽  
Atmospheric Conditions ◽  
Short Period ◽  
Dry Down ◽  
Spatio Temporal ◽  
Vegetation Water

Abstract. The process of soil drying following a single rainfall input offers an integrated perspective on soil-vegetation water dynamics in responses to atmospheric conditions during periods without rainfall. In this work, the soil moisture dry-down time scale events (τ) was calculated using surface soil moisture data from the SMOS mission, with the objective to explore if the spatio-temporal variability of τ could be used as a proxy for regional flooding and waterlogging characterization. Our working hypothesis is that soil moisture dries up more slowly under flooded conditions as a result of slower surface water elimination by infiltration and capillary rise of water from the saturated zone close to the surface. A clear difference precipitation-moisture coupling was detected between two regions with different flooding dynamics. In a region where flooding is triggered by precipitation excesses on weekly-to-monthly time scales and where the coupling between precipitation and evapotranspiration is strong, a positive correlation between dry-down and 6-month accumulated precipitation anomaly was found for all seasons except winter. By contrast, in the other region where flooding is largely de-coupled from precipitation and evapotranspiration, but rather coupled to ground water table dynamics on time scales from several months to years, no significant correlations were found. These results are based on a short period of data: March 2010 – November 2014.

A Broad Review of Variability and Persistence in the Northumberland Benthic Fauna – 1971–85

1986 ◽  
Vol 66 (3) ◽  
pp. 641-657 ◽  
Author(s):  
John B. Buchanan ◽  
J. Jonathan Moore
Keyword(s):  
Similarity Index ◽  
Benthic Fauna ◽  
Similar Response ◽  
Biological Interaction ◽  
Deep Station ◽  
Short Period ◽  
Shallow Station ◽  
Second Period ◽  
Term Monitoring

The long-term monitoring of two stations, 55 and 80 m depth, from 1971 to 1985 shows clear evidence of periods of stability interspersed with periods of change. These periods were identified by several different multivariate methods and persistence stability was quantified by the use of a between years similarity index. A short period of change at the shallow station, 1972–3, was followed by a prolonged period of stability 1974–80. The period 1981–3 witnessed a second period of change with rising total numbers and biomass with some evidence of a downward reversal in 1984–5. The deep station exhibited an essentially similar response except that the stable period 1974–80 was broken into two sub-periods 1974–6 and 1978–80 due to sequential changes in the dominant species which were regarded as evidence of biological interaction with the activities of the polychaete Ophelina acuminata possibly playing a key role. The shallow station showed little evidence of biological interaction and the majority of the species have exhibited similar responses throughout. The general rise in numbers and biomass at both stations is regarded as evidence of intermittent changes in organic flux to the bottom from the water column. The winter temperature fluctuations were shown to have short-term, but significant, effects on the diversity of the communities, bringing about year to year changes in the equitability and dominance.

Hydroptila eramosa a new caddis fly from Southern Ontario (Trichoptera, Hydroptilidae)

1973 ◽  
Vol 51 (3) ◽  
pp. 393-394
Author(s):  
P. P. Harper
Keyword(s):  
Adult Male ◽  
Similar Species ◽  
Southern Ontario ◽  
Caddis Fly

The adult male of Hydroptila eramosa n. sp. is described from Southern Ontario and is briefly compared with other similar species of the "waubesiana group."

Atmospheric Corrosion Protection of Metallic Structures Using Geocements-Based Coatings

2015 ◽  
Vol 227 ◽  
pp. 239-242
Author(s):  
Pavel Krivenko ◽  
Sergii Guzii ◽  
Hameedi Abdullah Jafar Al-Musaedi
Keyword(s):  
Atmospheric Corrosion ◽  
Protective Coatings ◽  
Atmospheric Conditions ◽  
Hydration Products ◽  
Optimal Parameters ◽  
Metallic Structures ◽  
High Adhesion ◽  
Short Period ◽  
New Generation ◽  
Target Synthesis

It is known that load-bearing metallic structures that are in service in the atmospheric conditions showed that are exposed to corrosion. The known-in-the art paint-and-lacquer protective coatings can provide protection of metal surfaces for a rather short period between 5 to 10 years. That is why these structures should be protected by the more advanced coatings of new generation, namely: geocement-based coatings which differ from the known-in-the-art binding materials by formation in the hydration products of the zeolite-like minerals and feldspathoids. The paper discusses substantiation of choice of geocement composition in the (хК, уna)2O⋅Al2O3⋅nSiO2⋅mH2O system, target synthesis of hydration products of the geocements matrix in the fields of dynamic cavitation, optimal parameters of cavitation treatment aimed at nanostructurization of the geocements matrix in order to synthesize zeolite-like and hydromicaceous phases, choice of appropriate hardening agents and fillers etc. for producing highly efficient protective coatings with high corrosion resistance, high adhesion to metallic substrate and durability.

scholarly journals Macrobenthic Assessment of the South Sandwich Islands Reveals a Biogeographically Distinct Polar Archipelago

2021 ◽  
Vol 8 ◽  
Author(s):  
Oliver T. Hogg ◽  
Anna-Leena Downie ◽  
Rui P. Vieira ◽  
Chris Darby
Keyword(s):  
Marine Protected Areas ◽  
Marine Protected Area ◽  
Benthic Fauna ◽  
Biodiversity Hotspot ◽  
The South ◽  
South Georgia ◽  
The World ◽  
Benthic Environment ◽  
South Sandwich Islands ◽  
Neighbouring Island

The sub-Antarctic South Sandwich Islands forms part of one of the largest marine protected areas (MPAs) in the world. Whilst the neighbouring island of South Georgia is known to be a biodiversity hotspot, very little was known about the benthic biodiversity or biogeography of the South Sandwich Islands. Here we present findings from the first biophysical assessment of this polar archipelago. Using open-access datasets, alongside results from a recent UK Government-funder Blue Belt expedition to the region, we assess how the island’s biodiversity is structured spatially and taxonomically and how this is driven by environmental factors. The South Sandwich Islands are shown to be both biologically rich, and biogeographically distinct from their neighbouring provinces. A gradient forest approach was used to map the archipelago’s benthic habitats which, based on the functional composition of benthic fauna and environmental characterisation of the benthic environment, demonstrated a distinct biogeographical north-south divide. This faunal and environmental discontinuity between the South Sandwich Islands and the rest of the MPA and between the different islands of the archipelago itself, highlights the importance of the zoned protection across the South Georgia and South Sandwich Islands Marine Protected Area.

scholarly journals The Quaternary Sedimentology and Stratigraphy of Small, Ice-Proximal, Subaqueous Grounding-Line Moraines in the Central Niagara Peninsula, Southern Ontario

2002 ◽  
Vol 55 (1) ◽  
pp. 75-86 ◽  
Author(s):  
John Menzies
Keyword(s):  
Lake Erie ◽  
Ice Sheet ◽  
Surface Expression ◽  
Aqueous Environment ◽  
Glacial Lakes ◽  
Southern Ontario ◽  
Short Period ◽  
Grounding Line ◽  
The Impact

abstract A series of small moraine ridges in the central Niagara Peninsula, southern Ontario, were investigated in order to understand the impact the retreating Lauren- tide Ice Sheet had on this area of Canada, in terms of the Quaternary sedimentology, stratigraphy and geomorphology. As the ice retreated from the Lake Erie Basin, the area was simultaneously inundated by a series of glacial lakes. The only surface expression of this retreat phase of the ice sheet are suites of small moraine ridges. The morphology, stratigraphy, and sedimentology of these ridges indicates that they were probably formed, over a short period of time, in an ice proximal sub- aqueous environment at the rapidly retreating grounding-line margin of the ice sheet. The sediments reveal a stratigraphy that indicates an association of grounded ice sheet and sub- aqueous marginal conditions.

scholarly journals PM10 EXCEEDANCE IN BULGARIA

2018 ◽  
Vol 6 ◽  
pp. 1129-1138
Author(s):  
Iliyana Naydenova ◽  
Tsvetelina Petrova ◽  
Rositsa Velichkova ◽  
Iskra Simova
Keyword(s):  
Air Quality ◽  
Ambient Air ◽  
Winter Period ◽  
Primary Role ◽  
Atmospheric Conditions ◽  
Residential Heating ◽  
Current State ◽  
Short Period ◽  
Legislative Framework

Despite the effort done by member states during the last decade, failure in the implementation of the Ambient Air Quality Directive is being continuously registered in many European cities for different air pollutants. One of the biggest concerns in Bulgaria is the exceeded PM10 concentration in the ambient air, measured in all six air quality zones during the winter period. This has induced numerous activities (at the national and European level) focused on the following issues: identification of the level of exceedance of the air quality norms for PM10; the general emission sources; the most prominent omissions and discrepancies in the legislative framework; the level of implementation of the prescribed measures and many others. However, the PM10 exceedance is still of a significant concern in at least 28 municipalities in Bulgaria. Thus, the present work introduces a brief report on the current state of the problem in the country. For that purpose, benchmarking analyses was applied for obtaining the range of discrepancies and the tendencies of the PM10 concentrations, monitored in the ambient air at the affected municipalities. The investigation was carried out using merely officially reported and freely accessible data and covered a relatively short period of time of six years. The latest national and European environmental reports present data confirming the primary role of residential heating and transport during the winter period as well as at the occurrence of particular atmospheric conditions.

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