Respiration of an Air-Breathing Catfish Clarias Batrachus (Linn.)

1971 ◽  
Vol 55 (2) ◽  
pp. 421-434
Author(s):  
B. N. SINGH ◽  
G. M. HUGHES
Keyword(s):  
Ambient Air ◽  
Clarias Batrachus ◽  
Free Access ◽  
Closed Chamber ◽  
Anabas Testudineus ◽  
Exposed Fish ◽  
Saturated Water ◽  
Oxygenated Water ◽  
The Mean ◽  
Co2 Release

1. The respiratory behaviour and the rate of O2 consumption and CO2 elimination has been studied in Clarias batrachus under different environmental conditions which were also designed to test its suitability for life in water and on land. 2. The mean V O2 from water and air is about 93 cc/kg/h. It consumes more O2 from air (58.4%) than from water (41.6%). The rate of CO2 release through the airbreathing organs is very low (RQ = 0.11), much more CO2 is released through the gills and skin in water. 3. When the fish is submerged under air-saturated water and prevented from surfacing V O2 is low (about 65 cc/kg/h). However, the fish does not struggle to breath air over a period of 6-8 h in aerated water. It exchanges about 17 % of O2 through the skin and the rest through the gills in aerated water. 4. If the fish is maintained in still water in a closed chamber V O2 is about 61 cc/kg/h. It starts to search for air once the O2 tension in water is reduced below 100 mmHg and this searching becomes vigorous below 60 mmHg (WPO2). 5. When exposed to air VCOCO2 is about 71 cc/kg/h; V O2 air-exposed fish is about 37 cc/kg/h; hence RQ in air is only 0.52. It shows independent respiration in air although POO2 in ambient air was reduced to about 80 mmHg and PCOCO2 rose to about 51 mmHg. 6. When the fish is kept in deoxygenated water but allowed free access to air, VOO2 is low, but RQ air is not reduced (0.51) from that of air-exposed fish. It shows dependent respiration under these conditions when aerial POO2 is reduced below 80 mmHg and PCOCO2 raised above 50 mmHg. 7. Clarias batrachus can live in deoxygenated water for several days if allowed free access to air, and appears to be more suited for life in poorly oxygenated water than Saccobranchus fossilis or Anabas testudineus.

Respiration in an Air-Breathing Fish, the Climbing Perch Anabas Testudineus Bloch

1970 ◽  
Vol 53 (2) ◽  
pp. 265-280
Author(s):  
G. M. HUGHES ◽  
B. N. SINGH
Keyword(s):  
Free Access ◽  
O2 Consumption ◽  
O2 Uptake ◽  
Experimental Conditions ◽  
Anabas Testudineus ◽  
Climbing Perch ◽  
Saturated Water ◽  
Oxygenated Water ◽  
The Mean ◽  
Normal Respiration

1. Respiration of the climbing perch Anabas has been studied under five different experimental conditions. (a) The mean O2 consumption of a fish allowed free access to air, is about 113 c.c./kg/h at 25°C. The fish obtain nearly equal amounts of oxygen through the gills and through the accessory organs. (b) The overall O2 consumption from water of a fish allowed free access to nitrogen is nearly the same as during normal respiration from water with access to air. (c) The O2 consumption is reduced when the fish is out of water and obtains all its oxygen from air. (d) The O2 consumption from air increases considerably when the fish is maintained in de-oxygenated water and depends upon surfacing for its oxygen supply. (e) The O2 consumption of a fish kept in aerated water and prevented from surfacing remains at a minimum level relative to the other four conditions. 2. Much more carbon dioxide is released through the gills than through the accessory organs (10:1) when the fish respires from aerated water with access to air. The accessory organs are much more important for O2 uptake. 3. The respiratory quotient is approximately 1 when the fish is in aerated water, with or without access to air, but is only 0.7 when the fish is out of water. 4. Anabas can live out of water for 6-10 h if protected from dehydration. It continues to breathe quietly in air-saturated water using its gills alone for shorter periods (6-8 h) when denied free access to air.

Gas Exchange with Air and Water in an Air-Breathing Catfish, Saccobranchus (≡Heteropneustes) Fossilis

1971 ◽  
Vol 55 (3) ◽  
pp. 667-682
Author(s):  
G. M. HUGHES ◽  
B. N. SINGH
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Consumption ◽  
Gas Exchange ◽  
Tap Water ◽  
Free Access ◽  
Experimental Conditions ◽  
Tropical Asia ◽  
Saturated Water ◽  
Oxygenated Water ◽  
Hypoxic Water

1. Gas exchange of Saccobranchus fossilis with water and air has been studied under various experimental conditions which were designed to simulate some of the conditions of tropical Asia. 2. In tap water the fish exchanges gases with both water and air. When kept in air-saturated water it can exchange gases with water alone for periods of 6-12 h or even more. In de-oxygenated water, with free access to air, it obtains oxygen from the air and can live for several days under these conditions. 3. In air-saturated water more oxygen is obtained from water (60%) than from air (40%), but in hypoxic water this ratio is reversed. 4. When the fish is submerged in water, free access to air being prevented, the oxygen consumption is reduced, even in air-saturated water. In hypoxic and hypercarbic water oxygen consumption is further reduced. In air-saturated water about 17% of the oxygen enters via the skin and the rest via the gills. When exchanging gases with water alone and subjected to a gradual hypoxia, the fish shows a less dependent respirator. 5. When the fish is removed from the water its oxygen consumption is reduced. A greater reduction occurs when the fish is kept in de-oxygenated water but allowed to breathe air. 6. When the fish is exchanging gases with both water and air very little carbon dioxide is released into the air (RQ = 0·17). The total RQ in fish removed from the water is low, i.e. 0·58. The fish can survive in hypercarbic water only, provided that the content of carbon dioxide does not exceed 14·5 volumes %, when surfacing becomes necessary.

scholarly journals Direct Calculation of Thermodynamic Wet-Bulb Temperature as a Function of Pressure and Elevation

2013 ◽  
Vol 30 (8) ◽  
pp. 1757-1765 ◽  
Author(s):  
Sayed-Hossein Sadeghi ◽  
Troy R. Peters ◽  
Douglas R. Cobos ◽  
Henry W. Loescher ◽  
Colin S. Campbell
Keyword(s):  
Air Temperature ◽  
Mean Absolute Error ◽  
Direct Calculation ◽  
Ambient Air ◽  
Absolute Error ◽  
Mean Square ◽  
Air Temperatures ◽  
Order Polynomial ◽  
The Mean ◽  
Very High

Abstract A simple analytical method was developed for directly calculating the thermodynamic wet-bulb temperature from air temperature and the vapor pressure (or relative humidity) at elevations up to 4500 m above MSL was developed. This methodology was based on the fact that the wet-bulb temperature can be closely approximated by a second-order polynomial in both the positive and negative ranges in ambient air temperature. The method in this study builds upon this understanding and provides results for the negative range of air temperatures (−17° to 0°C), so that the maximum observed error in this area is equal to or smaller than −0.17°C. For temperatures ≥0°C, wet-bulb temperature accuracy was ±0.65°C, and larger errors corresponded to very high temperatures (Ta ≥ 39°C) and/or very high or low relative humidities (5% < RH < 10% or RH > 98%). The mean absolute error and the root-mean-square error were 0.15° and 0.2°C, respectively.

scholarly journals Effects of Air Pollution on the Vital Capacity of Commercial Motorcyclists in Nigeria Population

2020 ◽  
pp. 1-7
Author(s):  
G. U. Ezeja ◽  
C. U. Onwudiwe ◽  
O. D. Nwodo ◽  
G. Umahi-Ottah ◽  
N. D. Nwobodo
Keyword(s):  
Air Pollution ◽  
Vital Capacity ◽  
Health Workers ◽  
Test Group ◽  
Ambient Air ◽  
Ambient Air Pollution ◽  
Control Group ◽  
African Countries ◽  
Measuring Device ◽  
The Mean

Background: Ambient air pollution is a serious challenge to human health in most West African countries including Nigeria. Objective: The objective of the study was to determine the effects of dust inhalation on the vital capacity of commercial motorcyclists in Abakaliki metropolis. Methods: 200 subjects participated in this study, 100 commercial motorcyclists (test group) and 100 non-motorcyclists (control group). The mean ± S.D of their age, height and weight were calculated. Vital capacity was measured using a spirometer. A questionnaire and consent form was filled by every participant before the commencement of the study. A handheld laser dust measuring device called air sampler PCE-PCO 1 was used to analyze the quantity, quality and sizes of particulate matters present in the research area. Data were analyzed using descriptive and inferential statistics; Mean and standard deviations were calculated and the Z-test was used to test if the mean were significantly different. Level of significance was set at 95%. Results: The age of participants were within the range of 25 – 30 years. Commercial motorcyclists were exposed to particulate matter 0.5, 1.0 and 2.5 µm. The vital capacity of commercial motorcyclists was significantly lower than that of non-motorcyclists (p =0.01). Furthermore, a significant decrease in the vital capacity of commercial motorcyclists was observed when correlated with the number of years spent in the job (p = 0.03). There was also a significant correlation between vital capacity and hours spent per week among commercial motorcyclists (r = 0.245). Conclusion: Commercial motorcyclists need to be encouraged to adopt respiratory health safety strategies like use of full-face helmets, practice of active cycle of breathing techniques and also, be educated on air pollution hazards by public health workers.

Changes in nucleoli and nucleolar fibrillar centres of chromaffin cells in rat adrenal medulla over a 24-hour period: an ultrastructural and stereological analysis

1985 ◽  
Vol 77 (1) ◽  
pp. 255-262
Author(s):  
A. Robaglia ◽  
R. Seite
Keyword(s):  
Adrenal Medulla ◽  
Chromaffin Cells ◽  
Extreme Values ◽  
Sympathetic Neurons ◽  
Cellular Level ◽  
Temporal Organization ◽  
Free Access ◽  
Stereological Analysis ◽  
The Mean ◽  
Two Parameters

A stereological and ultrastructural study was performed on the nucleoli of the adrenal medulla chromaffin cells of rats exposed to a standardized 12 h light/12 h dark cycle with free access to food and water. The animals were killed three at a time, every 4 h during the 24-h span and fixed by intracardiac perfusion. In these reticulated nucleoli, the stereological analysis over a 24-h period showed a variation dependent on the time of killing for the two parameters investigated, the mean nucleolar volume, Vnu, and the mean volume of the fibrillar centres, Vfc(nu). The minimal value occurred at 0300 h (dark span) and the maximal one at 0700 h (at the onset of the light span). Between these two extreme values, Vnu increased 1.8-fold and Vfc(nu) 5.3-fold. These data are compared with a previous description from our laboratory of circadian rhythm in nucleoli of sympathetic neurons of superior cervical ganglion in the same animals. Analogies and differences are pointed out, but apart from these considerations the present study provides a new example of temporal organization at the cellular level in the organelle involved in ribosomal RNA synthesis and ribosome assembly.

Effect of Maternal Race on Outcome of Preterm Infants in the Military

PEDIATRICS ◽  
1993 ◽  
Vol 91 (3) ◽  
pp. 572-577
Author(s):  
David N. Greenberg ◽  
Bradley A. Yoder ◽  
Reese H. Clark ◽  
Clifford A. Butzin ◽  
Donald M. Null
Keyword(s):  
Birth Weight ◽  
Low Birth Weight ◽  
Preterm Infants ◽  
Gestational Age ◽  
Military Hospital ◽  
Free Access ◽  
Multiple Gestation ◽  
Entire Study ◽  
The Mean ◽  
Maternal Race

Previous studies suggest that low birth weight black infants have less morbidity and birth-weight-specific mortality during the perinatal period than low birth weight white infants. We studied the effect of maternal race on outcome in preterm infants born at a military hospital that offers free access to obstetric and neonatal care. Between January 1, 1986, and December 31, 1991, data were prospectively collected on all 667 infants delivered at Wilford Hall USAF Medical Center with an estimated gestational age of less than 35 weeks. Three hundred ninety-two white infants and 165 black infants were included in the data analysis. The mean (±SD) birth weight was 1701 ± 65 g for white infants and 1462 ± 66 g for black infants. The mean estimated gestational age was 31.0 ± 3.2 weeks for white infants and 29.9 ± 3.8 weeks for black infants. Preeclampsia was more frequent in black mothers than in white mothers for the entire study population (21% vs 14%), but the birth weight differential between races remained after correction for preeclampsia. There were no significant differences between races in stillbirths, gender, maternal age, maternal transfer status, number of prenatal visits, or percentages of mothers with small-for-gestational-age infants, multiple-gestation infants, prolonged rupture of membranes, or initial prenatal visit during the first trimester. Intraventricular hemorrhage was more frequent in white infants at 27 through 29 weeks estimated gestational age (50% vs 13%). There were no significant differences between the two groups in survival or in the occurrence of severe infraventricular hemorrhage or bronchopulmonary dysplasia. It is concluded that preterm black infants are smaller than preterm white infants when matched for gestational age despite essentially equal utilization of prenatal care. However, maternal race has little direct effect on the survival of liveborn preterm infants in this population.

scholarly journals An intercomparison study of analytical methods used for quantification of levoglucosan in ambient aerosol filter samples

2014 ◽  
Vol 7 (7) ◽  
pp. 7397-7450 ◽  
Author(s):  
K. E. Yttri ◽  
J. Schnelle-Kreiss ◽  
W. Maenhaut ◽  
C. Alves ◽  
R. Bossi ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Biomass Burning ◽  
Analytical Methods ◽  
High Performance ◽  
Ambient Air ◽  
Ambient Aerosol ◽  
Wood Burning ◽  
Monosaccharide Anhydrides ◽  
The Mean ◽  
Aerosol Filter

Abstract. The monosaccharide anhydrides (MAs) levoglucosan, galactosan and mannosan are products of incomplete combustion and pyrolysis of cellulose and hemicelluloses, and are found to be major constituents of biomass burning aerosol particles. Hence, ambient aerosol particle concentrations of levoglucosan are commonly used to study the influence of residential wood burning, agricultural waste burning and wild fire emissions on ambient air quality. A European-wide intercomparison on the analysis of the three monosaccharide anhydrides was conducted based on ambient aerosol quartz fiber filter samples collected at a Norwegian urban background site during winter. Thus, the samples' content of MAs is representative for biomass burning particles originating from residential wood burning. The purpose of the intercomparison was to examine the comparability of the great diversity of analytical methods used for analysis of levoglucosan, mannosan and galactosan in ambient aerosol filter samples. Thirteen laboratories participated, of which three applied High-Performance Anion-Exchange Chromatography (HPAEC), four used High-Performance Liquid Chromatography (HPLC) or Ultra-Performance Liquid Chromatography (UPLC), and six resorted to Gas Chromatography (GC). The analytical methods used were of such diversity that they should be considered as thirteen different analytical methods. All of the thirteen laboratories reported levels of levoglucosan, whereas nine reported data for mannosan and/or galactosan. Eight of the thirteen laboratories reported levels for all three isomers. The accuracy for levoglucosan, presented as the mean percentage error (PE) for each participating laboratory, varied from −63 to 23%; however, for 62% of the laboratories the mean PE was within ±10%, and for 85% the mean PE was within ±20%. For mannosan, the corresponding range was −60 to 69%, but as for levoglucosan, the range was substantially smaller for a subselection of the laboratories; i.e., for 33% of the laboratories the mean PE was within ±10%. For galactosan, the mean PE for the participating laboratories ranged from −84 to 593%, and as for mannosan 33% of the laboratories reported a mean PE within ±10%. The variability of the various analytical methods, as defined by their minimum and maximum PE value, was typically better for levoglucosan than for mannosan and galactosan, ranging from 3.2 to 41% for levoglucosan, from 10 to 67% for mannosan, and from 6 to 364% for galactosan. For the levoglucosan to mannosan ratio, which may be used to assess the relative importance of softwood vs. hardwood burning, the variability only ranged from 3.5 to 24%. To our knowledge, this is the first major intercomparison on analytical methods used to quantify monosaccharide anhydrides in ambient aerosol filter samples conducted and reported in the scientific literature. The results show that for levoglucosan the accuracy is only slightly lower than that reported for analysis of SO42− on filter samples, a constituent that has been analyzed by numerous laboratories for several decades, typically by ion chromatography, and which is considered a fairly easy constituent to measure. Hence, the results obtained for levoglucosan with respect to accuracy are encouraging and suggest that levels of levoglucosan, and to a lesser extent mannosan and galactosan, obtained by most of the analytical methods currently used to quantify monosaccharide anhydrides in ambient aerosol filter samples, are comparable. Finally, the various analytical methods used in the current study should be tested for other aerosol matrices and concentrations as well, the most obvious being summertime aerosol samples affected by wild fires and/or agricultural fires.

scholarly journals Compliance and port air quality features with respect to ship fuel switching regulation: a field observation campaign, SEISO-Bohai

2019 ◽  
Vol 19 (7) ◽  
pp. 4899-4916 ◽  
Author(s):  
Yanni Zhang ◽  
Fanyuan Deng ◽  
Hanyang Man ◽  
Mingliang Fu ◽  
Zhaofeng Lv ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Air Quality ◽  
Sulfur Content ◽  
Ambient Air ◽  
Ship Emissions ◽  
Study Region ◽  
Fuel Switching ◽  
The Mean ◽  
Hourly Concentration ◽  
Low Sulfur

Abstract. Since 1 January 2017, ships berthed at the core ports of three designated “domestic emission control areas” (DECAs) in China should be using fuel with a sulfur content less than or equal to 0.5 %. In order to evaluate the impacts of fuel switching, a measurement campaign (SEISO-Bohai) was conducted from 28 December 2016 to 15 January 2017 at Jingtang Harbor, an area within the seventh busiest port in the world. This campaign included meteorological monitoring, pollutant monitoring, aerosol sampling and fuel sampling. During the campaign, 16 ship plumes were captured by the on-shore measurement site, and 4 plumes indicated the usage of high-SF (SF refers to the sulfur content of marine fuels). The average reduction of the mean ΔNOx∕ΔSO2 ratio from high-sulfur plumes (3.26) before 1 January to low-sulfur plumes (12.97) after 1 January shows a direct SO2 emission reduction of 75 %, consistent with the sulfur content reduction (79 %). The average concentrations of PM2.5 (particulate matter with a diameter less than 2.5 µm), NOx, SO2, O3 and CO during campaign were 147.85 µg m−3, 146.93, 21.91, 29.68 ppb and 2.21 ppm, respectively, among which NOx reached a maximum hourly concentration of 692.6 ppb, and SO2 reached a maximum hourly concentration of 165.5 ppb. The mean concentrations of carbonaceous and dominant ionic species in particles were 6.52 (EC – elemental carbon), 23.10 (OC – organic carbon), 22.04 (SO42-), 25.95 (NO3-) and 13.55 (NH4+) µg m−3. Although the carbonaceous species in particles were not significantly affected by fuel switching, the gas and particle pollutants in the ambient air exhibited clear and effective improvements due to the implementation of low-sulfur fuel. Comparison with the prevailing atmospheric conditions and a wind map of SO2 variation concluded a prompt SO2 reduction of 70 % in ambient air after fuel switching. Given the high humidity at the study site, this SO2 reduction will abate the concentration of secondary aerosols and improve the acidity of particulate matter. Based on the enrichment factors of elements in PM2.5, vanadium was identified as a marker of residual fuel ship emissions, decreasing significantly by 97.1 % from 309.9 ng m−3 before fuel switching to 9.1 ng m−3 after regulation, which indicated a crucial improvement due to the implementation of low-sulfur fuels. Ship emissions were proven to be significantly influential both directly and indirectly on the port environment and the coastal areas around Bohai Bay, where the population density reaches over 650 people per square kilometer. The results from this study report the positive impact of fuel switching on the air quality in the study region and indicate a new method for identifying the ship fuel type used by vessels in the area.

Occupational exposure to mercury vapor in a compact fluorescent lamp factory: Evaluation of personal, ambient air, and biological monitoring

2019 ◽  
Vol 35 (4) ◽  
pp. 304-313 ◽  
Author(s):  
Ebrahim Darvishi ◽  
Mohammad Javad Assari ◽  
Maryam Farhadian ◽  
Ebrahim Chavoshi ◽  
Hamid Reza Ehsani
Keyword(s):  
Occupational Exposure ◽  
Light Emitting Diode ◽  
Mercury Level ◽  
Mercury Vapor ◽  
Ambient Air ◽  
Cross Sectional Study ◽  
Cross Sectional ◽  
Air Samples ◽  
The Mean ◽  
Occupational Exposure To Mercury

Compact fluorescent lamps (CFLs) have become a popular lighting choice in recent years despite the good performance of light-emitting diode (LED) lamps. The CFLs that have been produced recently contain 1.5–3.5 mg Hg/lamp. There is evidence that even low doses of mercury are toxic. This study aimed to assess occupational exposure to mercury vapor in workers of a CFLs factory by determining mercury levels in personal and ambient air samples and urine of workers. This cross-sectional study was conducted on 59 workers in a CFLs factory in Iran. Personal and ambient air sampling of mercury vapor levels (MVLs) was performed during a workday. In total, 10 personal samples and 10 ambient air samples of mercury vapor were collected simultaneously from different units of the factory. Urine samples were collected before the work shift. Samples were analyzed using a cold-vapor atomic absorption spectrophotometer (CVAAS). The mean of the MVLs in the personal and ambient air samples was 14.78 ± 5.76 and 67.10 ± 59.37 µg.m−3, respectively. The highest MVL was measured for the production line supervisor (25 µg.m−3). There was a significant correlation between the MVLs in the ambient air and personal samples ( r = 0.84, p = 0.005). The mean urinary mercury level (UML) was 13.85 ± 13.14 µg/g creatinine. The UML of 86.4% workers was below the 20 µg/g creatinine recommended by the Centre of Environmental and Occupational Health in Iran. There were significant differences between the UMLs in different areas of the factory ( p = 0.041). Lamp breakage was an important determinant of exposure to mercury vapor; hence, effective programs to control mercury vapor are essential in the CFLs industry.

Evaluation of continuous δ13CH4 measurements in Heidelberg and at Schauinsland, Germany

2020 ◽  
Author(s):  
Antje Hoheisel ◽  
Frank Meinhardt ◽  
Martina Schmidt
Keyword(s):  
Isotopic Composition ◽  
Mole Fraction ◽  
Isotope Analysis ◽  
Ambient Air ◽  
Peak Height ◽  
West Germany ◽  
Livestock Farming ◽  
Biogenic Methane ◽  
The Mean ◽  
Instrumental Development

<p>Instrumental development in measurement technique now allows continuous in-situ isotope analysis of <sup>13</sup>CH<sub>4</sub> by Cavity Ring-Down Spectroscopy (CRDS). Analyses of the isotopic composition of methane in ambient air can potentially be used to partition between different CH<sub>4</sub> source categories.</p><p>Since 2014 a CRDS G2201-i analyser has been used to continuously measure CH<sub>4</sub> and its <sup>13</sup>C/<sup>12</sup>C ratio in ambient air at the Institute of Environmental Physics (IUP) in Heidelberg (116m a.s.l.), South-West Germany. Furthermore, the CRDS G2201-i analyser was installed twice for a month at the measurement station of the German Environment Agency at Schauinsland (1205m a.s.l.). In September 2018 and in February 2019 the analyser was moved to Schauinsland to examine the validity of evaluations of continuous δ<sup>13</sup>CH<sub>4 </sub>measurements at a semi-rural station.</p><p>As an urban station, the seasonal and daily variations of the measured CH<sub>4</sub> mole fraction and isotopic composition in Heidelberg vary much stronger than at the mountain station Schauinsland. The precision of the isotopic source signature calculation using a Keeling plot strongly depends on the CH<sub>4</sub> peak height and instrumental precision. Therefore, at Schauinsland station the lower variability in the CH<sub>4</sub> mole fraction makes the evaluation challenging. Different methods such as monthly/weekly interval evaluations and moving Keeling/Miller Tans methods has been used to calculate the isotopic source signature in ambient air.</p><p>The isotopic methane source signatures of the air in Heidelberg was found to be between -75 ‰ and -35 ‰, with an average of (-54 ± 2) ‰. An annual cycle can be noticed with more depleted values (-56 ‰) in summer and more enriched values (-51 ‰) in winter, due to larger biogenic emissions in summer and more thermogenic (e.g. natural gas) emissions in winter. The mean isotopic source signature calculated at Schauinsland shows variations, too, with more enriched values (−56 ‰) in winter and more depleted (−60 ‰) ones in autumn. The more depleted values in summer/autumn at Schauinsland corresponds to more biogenic methane and can be explained by dairy cows grazing near the station especially during this time.</p><p>The generally more enriched values at Schauinsland are caused by the more rural surrounding. Emission estimates of county provided by the LUBW Landesanstalt für Umwelt Baden-Württemberg shows that around Schauinsland 60 % of the CH<sub>4</sub> emissions are emitted by livestock farming and around Heidelberg only 28 %. The mean isotopic source signature calculated using these emissions is (-58 ± 2) ‰ for Schauinsland and (-53 ± 2) ‰ for Heidelberg. These results agreed well with the mean source signatures determined out of continuous isotopic measurements.</p>

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