A Paleolimnological Assessment of Acidification and Liming Effects on Diatom Assemblages in a Swedish Lake

1992 ◽  
Vol 49 (1) ◽  
pp. 65-72 ◽  
Author(s):  
Ingemar Renberg ◽  
Hans Hultberg
Keyword(s):  
Historical Data ◽  
Severe Damage ◽  
Ph Values ◽  
Documentary Sources ◽  
Forest Lakes ◽  
Water Ph ◽  
Synedra Acus ◽  
Inferred Ph ◽  
The 1960S ◽  
Acid Episodes

In Sweden, about 6000 lakes have been limed to mitigate acidification. Lysevatten (southwestern Sweden) was limed in 1974 and 1986 and has better historical pH and fish records than most other, similar forest lakes. Historical data were compared with diatom analyses of a sediment core to assess to what extent diatom-inferred pH reflects the known pH history. The diatom-inferred pH history agrees well with the development known from documentary sources, although the sediment record is slightly smoothed. Both the historical and sediment records show that the acidification, with acid episodes that caused severe damage to lake biota, began during the 1940s and became acute in the 1960s, with pH values of 4.5–4.9. Prior to acidification, lake water pH was between 6 and 7, and the lake had a planktonic Cyclotella flora. The liming increased pH to 7.5 and resulted in the expansion of Achnanthes minutissima agg., Cymbella microcephala, and Synedra acus. The reacidification is reflected by a decrease of the abundance of these species. Neither the liming in 1974 nor that in 1986 restored the preacidification diatom flora; there was no recovery of Cyclotella.

scholarly journals A new diatom training set for the reconstruction of past water pH in the Tatra Mountain lakes

2021 ◽  
Author(s):  
Elwira Sienkiewicz ◽  
Michał Gąsiorowski ◽  
Ladislav Hamerlík ◽  
Peter Bitušík ◽  
Joanna Stańczak
Keyword(s):  
Surface Sediments ◽  
Tatra Mountains ◽  
Training Set ◽  
Statistical Parameters ◽  
The Past ◽  
Water Ph ◽  
Inferred Ph ◽  
The 1960S ◽  
The Tatra Mountains ◽  
The Relationship

AbstractLakes located in the Polish and Slovak parts of the Tatra Mountains were included in the Tatra diatom database (POL_SLOV training set). The relationship between the diatoms and the water chemistry in the surface sediments of 33 lakes was the basis for the statistical and numerical techniques for quantitative pH reconstruction. The reconstruction of the past water pH was performed using the alpine (AL:PE) and POL_SLOV training sets to compare the reliability of the databases for the Tatra lakes. The results showed that the POL_SLOV training set had better statistical parameters (R2 higher by 0.16, RMSE and max. bias lower by 0.2 and 0.36, respectively) compared to the AL:PE training set. The better performance of the POL_SLOV training set is particularly visible in the case of Przedni Staw Polski where the curve of the inferred water pH shows an opposite trend for the period from the 1960s to 1990 compared to that based on the AL:PE dataset. The reliability of the inferred pH was confirmed by the comparison with current instrumental measurements.

Surface-sediment chrysophytes from 35 Quebec lakes and their usefulness in reconstructing lake-water pH

1989 ◽  
Vol 67 (7) ◽  
pp. 2071-2076 ◽  
Author(s):  
Aruna S. Dixit ◽  
Sushil S. Dixit
Keyword(s):  
Surface Sediment ◽  
Lake Water ◽  
Predictive Ability ◽  
Strong Relationship ◽  
Ph Indicator ◽  
Ph Values ◽  
Water Ph ◽  
History Of ◽  
Inferred Ph ◽  
Water Acidity

Chrysophyte scales from surface sediment samples of 35 Quebec lakes were analyzed to examine their relationship with lake-water pH. The percent composition of common chrysophyte taxa were plotted against the measured lake-water pH. The distribution of many taxa was found to be closely associated with pH. The pH indicator status and abundance-weighted mean pH values of the majority of taxa of the studied region agreed with the published work. Chrysophyte counts were quantified to establish a predictive pH model using multiple regressions of pH indicator chrysophyte assemblages with lake-water pH. A strong relationship (r2 = 0.72) was observed between measured and inferred pH values. The pH predictive ability of chrysophytes was further corroborated by reconstructing the recent pH history of Lake Bonneville. Over the last 30 years, the inferred pH of this lake has declined ≈ 1 pH unit. The present study accentuates that stratigraphic analysis of chrysophytes will provide useful measurements of the extent of lake-water acidity in Quebec.

scholarly journals Development of a Low-Cost pH Meter for Liquid Chemical Fertilizers

2020 ◽  
Vol 8 (4) ◽  
pp. 840-846
Author(s):  
Muhittin Yağmur Polat ◽  
Abdullah Beyaz ◽  
İbrahim Çilingir
Keyword(s):  
Ph Value ◽  
Low Cost ◽  
Ph Sensor ◽  
Field Application ◽  
Average Error ◽  
Chemical Fertilizers ◽  
Modern Agriculture ◽  
Ph Values ◽  
Water Ph ◽  
Liquid Chemical

Liquid chemical fertilizers are widely used in modern agriculture. The pH values of these fertilizers are important in terms of their effectiveness in the field application and their effect on the soil-water pH balance. Therefore, it is necessary to measure the pH and other properties of liquid fertilizers with fast, practical and inexpensive methods. With the advancing technology, pH value has been started to measure more accurately and efficiently with the help of low-cost devices. In this study, a low-cost pH meter was developed using a low-cost pH sensor, an Arduino UNO R3 microcontroller board, and a software written in the C/C++ programming language. The developed pH meter was used to measure the pH values of liquid chemical fertilizers. Close variations were observed between the values obtained from it and the values measured by an accredited, laboratory-type pH meter. According to the pH measurements of the two pH meters, R2 ranged 88.1% to 99.3%, average error range 0.14 to 0.28, and average error percentage ranged 1.56% to 6.81% for three different types of liquid fertilizers. In light of these results, it was shown that the developed low-cost pH meter can be useful for practical pH measurement applications.

Assessment of Changes in Lake Water Chemistry in Sudbury Area Lakes since Preindustrial Times

1992 ◽  
Vol 49 (S1) ◽  
pp. 8-16 ◽  
Author(s):  
Sushil S. Dixit ◽  
Aruna S. Dixit ◽  
John P. Smol
Keyword(s):  
Lake Water ◽  
Acidic Ph ◽  
Prevailing Wind ◽  
Alkaline Ph ◽  
Sediment Samples ◽  
Ion Concentrations ◽  
The Past ◽  
Lake Water Chemistry ◽  
Water Ph ◽  
Inferred Ph

Surface (recent) and bottom (pre-1880s) sediment samples from each of 72 Sudbury area lakes were analyzed for diatom valves and chrysophyte scales, and using these microfossils, we inferred changes in lake water pH, [Al], [Ni], conductance, and [Ca]. The study shows that extensive acidification has occurred in presently acidic (pH < 6.0) Sudbury lakes. Inferred [Al] has also increased in these lakes. The region also contains a few naturally acidic lakes; however, even these lakes have acidified further since the bottom sediments were deposited. Lakes that have current measured pH between 6.0 and 7.0 have either declined or increased in inferred pH in the past, whereas all lakes that are presently alkaline (pH > 7.0) have become more alkaline. The increase in inferred [Ni] in most of the study lakes indicates that Ni inputs are mainly atmospheric. Our data suggest that, in general, ion concentrations have increased in Sudbury lakes. The extent of acidification or alkalification in Sudbury lakes was primarily a function of proximity of the lakes to the smelters, orientation of prevailing wind patterns, and differences in watershed geology.

scholarly journals Fine particle pH for Beijing winter haze as inferred from different thermodynamic equilibrium models

2018 ◽  
Author(s):  
Shaojie Song ◽  
Meng Gao ◽  
Weiqi Xu ◽  
Jingyuan Shao ◽  
Guoliang Shi ◽  
...  
Keyword(s):  
Measurement Errors ◽  
North China ◽  
Fine Particles ◽  
Bimodal Distribution ◽  
Ionic Species ◽  
Phase Measurements ◽  
Ph Values ◽  
Reverse Mode ◽  
Inferred Ph ◽  
Ambient Measurements

Abstract. pH is an important property of aerosol particles but is difficult to measure directly. Several studies have estimated the pH values for fine particles in North China winter haze using thermodynamic models (i.e., E-AIM and ISORROPIA) and ambient measurements. The reported pH values differ widely, ranging from close to 0 (highly acidic) to as high as 7 (neutral). In order to understand the reason for this discrepancy, we calculated pH values using these models with different assumptions with regard to model inputs and particle phase states. We find that the large discrepancy is due primarily to differences in the model assumptions adopted in previous studies. Calculations using only aerosol phase composition as inputs (i.e., reverse mode) are sensitive to the measurement errors of ionic species and inferred pH values exhibit a bimodal distribution with peaks between −2 and 2 and between 7 and 10. Calculations using total (gas plus aerosol phase) measurements as inputs (i.e., forward mode) are affected much less by the measurement errors, and results are thus superior to those obtained from the reverse mode calculations. Forward mode calculations in this and previous studies collectively indicate a moderately acidic condition (pH from about 4 to about 5) for fine particles in North China winter haze, indicating further that ammonia plays an important role in determining this property. The differences in pH predicted by the forward mode E-AIM and ISORROPIA calculations may be attributed mainly to differences in estimates of activity coefficients for hydrogen ions. The phase state assumed, which can be either stable (solid plus liquid) or metastable (only liquid), does not significantly impact pH predictions of ISORROPIA.

scholarly journals Właściwości alkalizujące wybranych krzemianowo-wapniowych uszczelniaczy kanałowych. Badanie in vitro

2018 ◽  
Vol 64 (4) ◽  
Author(s):  
Przemysław Reszka ◽  
Łukasz Kucharski ◽  
Adam Klimowicz ◽  
Mariusz Lipski
Keyword(s):  
Root Canal ◽  
Calcium Silicate ◽  
In Vitro Study ◽  
Root Canal Sealer ◽  
Ph Values ◽  
Water Ph ◽  
Ah Plus ◽  
Ph Level ◽  
Root Canal Sealers

ABSTRACTIntroduction: The aim of this in vitro study was to assess the pH values of selected calcium-silicate root canal sealers in comparison with AH Plus resin-based root canal sealer.Materials and methods: Six root canal sealers were included in this study: BioRoot RCS (Septodont, France), GuttaFlow bioseal (Coltėne/Whaledent, Switzerland), MTA Fillapex (Angelus, Brazil), Total Fill BC Sealer (FKG, Switzerland), Well-Root ST (Vericom, Korea) and AH Plus (Dentsply, DeTrey, Germany). Materials samples (n = 6) were placed in dishes and immersed in 10 mL of distilled water (pH = 6.8). After 1, 3, 24, 48, 72, 168, 336 and 504 hrs, water pH was determined with a pH meter calibrated with a solution of known pH. Data were statistically analyzed using Student-t test (p < 0.05).Results: There were differences in the water pH between the materials tested. The highest water pHs were exhibited by Total Fill BC Sealer, Well-Root ST and BioRoot RCS (pH ~12), followed by GuttaFlow bioseal (pH ~10.5) and MTA Fillapex (pH ~9). The lowest pH was shown by AH Plus (pH ~8).Conclusions: All calcium-silicate root canal sealers studied are able to elevate the pH level, which could have biological and antimicrobial effects. The AH Plus root canal sealer has poor alkalizing properties.

scholarly journals ARQUITETURA PRODUZIDA EM PRESIDENTE PRUDENTE: FORMAÇÃO E DESENVOLVIMENTO DA CIDADE ATÉ A DÉCADA DE 1960

2011 ◽  
Vol 08 (1) ◽  
pp. 09-15
Author(s):  
Cristiana A. Pasquini Feltrin Marques
Keyword(s):  
Urban Development ◽  
Historical Data ◽  
Developmental Period ◽  
Urban Transformation ◽  
City Development ◽  
Architectural Language ◽  
Using Data ◽  
The 1960S ◽  
First Moment ◽  
The City

This version intends to broach the historical data for training and organization of the city, as well as presenting the city -the context object of this research. Proposes the identification of the architectural language of the city in theformative years, as well as the trajectory of the production in developmental period. From the discussions proposed by the graphics, the article has these objectives: The first moment make a survey the city, understanding the process of urban transformation until the 1960s, then intended to know the production architectural inserted in that period. The method is build with analysis applicants and scientific research simple and objective. Will it develop, in principle, using data on urban development and city development

scholarly journals The Factors Influences of pH or Acidity Level in The Urban Area

2018 ◽  
Author(s):  
wiwit suprihatiningsih ◽  
TITIA IZZATI ◽  
kis yoga utomo ◽  
sandi novandi ◽  
nurhakim ◽  
...  
Keyword(s):  
Urban Area ◽  
Water Samples ◽  
Household Waste ◽  
Measuring Instruments ◽  
Traffic Intensity ◽  
Residential Areas ◽  
Industrial Areas ◽  
Ph Values ◽  
Water Ph ◽  
Acidity Level

This research aims to study the acidity or the water’s pH in Bekasi, Bogor, Depok and East Jakarta. The purpose is to determine what kind of factors influence the pH intensity in the above mentioned cities. This research methods are performed by taking water samples in residentials, or industrial areas to be investigated with the pH measuring instruments. This research will analyze any factors that cause changes in water condition of these cities. pH values at residential areas: Bekasi 7.4, Bogor 7.5, Depok 7.7 and East Jakarta 7.8 and and at industrial areas, of the same cities show a remarquable difference such as: Bekasi 8.7, Bogor 8.2, Depok 8.3 and East Jakarta 8.2. These water pH differences are influenced by industries factor, household waste, or the traffic intensity in any of these cities.

Medieval Castles of Britain and Ireland from the 11th to the 15th Century

2020 ◽  
Author(s):  
John R. Kenyon
Keyword(s):  
Middle Ages ◽  
Civil Wars ◽  
13Th Century ◽  
Norman Conquest ◽  
Medieval Architecture ◽  
Documentary Sources ◽  
15Th Century ◽  
Dominant Feature ◽  
Norman Invasion ◽  
The 1960S

The study of this subject has a long pedigree, from the late 18th and 19th centuries, although material of this date has varying degrees of authority in the light of more recent work since the 1960s. The first castles in England appear in the 1050s, built by Norman favorites of King Edward the Confessor (r. 1042–1066) and were few in numbered and mainly in the English county of Herefordshire, on the border with Wales. Following the Norman Conquest of 1066, earth-and-timber castles of both the motte and bailey and the ringwork forms were built throughout England, in towns and in the countryside, and where the Normans moved into Wales and Scotland. The first castles in Ireland appear after the Anglo-Norman invasion of 1169; the matter of medieval private fortifications in pre-Norman areas is not discussed here. Some of the first castles were built in stone from the beginning, examples being the Tower of London, Chepstow in Monmouthshire and Richmond in Yorkshire. The development of the masonry castle as fortification, home, and administrative center is a feature of the history of medieval architecture. The great tower or keep is a dominant feature of the 12th- and 13th-century castle, although these towers can be found as late as the 15th century. Strong defenses through twin-towered gatehouses and mural towers along the curtain walls are hallmarks of defenses, but these towers also provided accommodation. Domestic features such as halls, private chambers, kitchens, stables, and other ancillary buildings would be found in the interiors, while gardens either inside the walls or immediately outside are known from documentary sources. The later Middle Ages, from the 14th century, witnessed few new castles built, apart from the tower houses of Ireland and Scotland, but in England in particular there was a growing sophistication in the domestic ranges built both by the monarch and the great lords of the land. While several of the major castles remain occupied as homes, many earth and timber structures had a limited life, particularly in England, with examples of longer use elsewhere, while others suffered in the British civil wars between king and parliament of the 1640s.

Scaled Chrysophytes (Chrysophyceae) as Indicators of pH in Sudbury, Ontario, Lakes

1988 ◽  
Vol 45 (8) ◽  
pp. 1411-1421 ◽  
Author(s):  
Sushil S. Dixit ◽  
Aruna S. Dixit ◽  
R. Douglas Evans
Keyword(s):  
Lake Water ◽  
Ph Indicator ◽  
Related Factors ◽  
Scaled Chrysophytes ◽  
Calibration Equation ◽  
Water Ph ◽  
History Of ◽  
Inferred Ph ◽  
Relationship Of ◽  
The Relationship

Surface sediment chrysophytes (Chrysophyceae) of 30 Sudbury, Ontario, lakes were analyzed to investigate the relationship of these algal microfossils with the limnological characteristics of the study lakes. The distribution of the majority of common chrysophyte taxa is correlated closely with lake water pH, pH-related factors, or both. Chrysodidymus synuroideus, Synura echinulata, Mallomonas hamata, M. acaroides var. muskokana, and Chrysosphaerella longispina appear to be indicators of strongly to moderately acidic waters whereas M. pseudocoronata and M. caudata are indicators of circumneutral to alkaline waters. Using multiple regression of pH indicator chrysophyte assemblages against the measured lake pH, a calibration equation was developed to compute chrysophyte-inferred pH. Chrysophyte-inferred pH values were closely related with measured lake water pH (r2 = 0.74). The study indicates that in the absence of historical pH data, stratigraphic analysis of scaled chrysophytes would provide useful information about the history of lake acidification in the Sudbury area. There is some indication that high metal concentrations, in addition to pH, may influence chrysophycean species distribution in acidic lakes.

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