Factors Affecting Winter Respiration in Ontario Lakes

1976 ◽  
Vol 33 (8) ◽  
pp. 1809-1815 ◽  
Author(s):  
H. E. Welch ◽  
P. J. Dillon ◽  
A. Sreedharan
Keyword(s):  
Oxygen Consumption ◽  
Chlorophyll A ◽  
Secchi Depth ◽  
Factors Affecting ◽  
Respiration Rates ◽  
Morphological Variables

Winter oxygen consumption was measured in 16 Ontario lakes. Whole lake respiration ranged from 0.08 to 0.39 g O2 m−2 day−1 and was positively correlated with mean depth, phosphorus m−2 at spring overturn, and summer chlorophyll a m−2. Morphological variables plus Secchi depth were explained over 80% of the variability in respiration rates.

Decomposition of Seston in the Hyolimnion

1987 ◽  
Vol 44 (1) ◽  
pp. 146-151 ◽  
Author(s):  
R. J. Cornett ◽  
F. H. Rigler
Keyword(s):  
Oxygen Consumption ◽  
Water Temperature ◽  
Water Column ◽  
Chlorophyll A ◽  
Significant Fraction ◽  
Oxygen Deficit ◽  
Total Oxygen ◽  
Respiration Rates ◽  
Hypolimnetic Oxygen

In 12 lakes a significant fraction of the hypolimnetic oxygen deficit was produced by the respiration of seston in the hypolimnetic water column. Mean summer seston respiration rates ranged between 4 and 80 mg O2∙m−3∙d−1. Rates of seston respiration were proportional to the in situ water temperature and to the concentration of Chlorophyll a. The amount of oxygen consumed in the water column and the fraction of the total oxygen deficit produced by sestonic respiration were correlated with the amount of phosphorus sedimented from the epilimnion. Fifteen to 66% of the total oxygen consumption occurred in the water column of the hypolimnion. Seston respiration was a larger proportion of the total respiration in the hypolimnion of lakes with a thick hypolimnion than in lakes with a shallow hypolimnetic water column.

scholarly journals A Study on Trophic State in Lakes of Dong Da District, Hanoi

2017 ◽  
Vol 33 (4) ◽  
Author(s):  
Nguyen Thi The Nguyen
Keyword(s):  
Chlorophyll A ◽  
Algal Biomass ◽  
Trophic State ◽  
Secchi Depth ◽  
Limiting Factors ◽  
Factors Affecting ◽  
Large Particles ◽  
The Difference ◽  
Time Plot

One of approaches to assessing the condition of lakes is to look at lakes with respect to their primary production or trophic state. Protecting water quality of urban lakes from eutrophication is an important task of all governments. This study presents an analysis of the trophic state in lakes of Dong Da district, Hanoi. The tropic states of the lakes were characterized using the Carlson TSI and the Chlorophyll-a concentrations with the thresholds of US. The deviations of the Secchi depth and total phosphorus indices from the Chlorophyll-a index were used to identify limiting factors affecting to the tropic state of the lakes. It comes to a conclusion that most of the lakes in study area were hypereutrophic or eutrophic in August 2017 and eutrophic or oligotropic in March 2017. It also reveals that phosphorus were not limited factor for algal biomass but some factors such as nitrogen limitation, zooplankton grazing or toxics limit algal biomass. The time plot method suggested that transparency were dominated by non-algal factors such as color or turbidity or where very small particles predominated, whereas the difference plot method revealed that large particles were dominated. Consequently, more studies should be done to look for the real limiting factors and conditions of the lakes.

The effect of the acanthocephalan Pomphorhynchus laevis upon the respiration of its intermediate host, Gammarus pulex

Parasitology ◽  
1974 ◽  
Vol 68 (2) ◽  
pp. 271-284 ◽  
Author(s):  
A. E. Rumpus ◽  
C. R. Kennedy
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Uptake ◽  
Host Population ◽  
Gammarus Pulex ◽  
Multiple Infections ◽  
Pomphorhynchus Laevis ◽  
Respiration Rates ◽  
Physiological Processes ◽  
Stage Of Development ◽  
Host Parasite

The respiration rates of individual Gammarus pulex infected by larval Pomphorhynchus laevis were investigated with particular reference to the stage of development of the host and parasite and to the water temperature. At 20°C the oxygen consumption of Gammarus of all sizes was reduced by an average of 19·3 % by the presence of cystacanths of the parasite, but was unaffected by the presence of acanthellae. It is considered that the small size of this larval stage, in relation to that of its host, is responsible for the failure to detect an effect. Multiple infections did not exert any greater effect upon host respiration than single cystacanths, nor did it appear that the parasite had different effects upon hosts of different sexes. At 10°C no significant differences were observed between the respiration rates of infected and uninfected gammarids. The parasite was probably still depressing the host respiration rate at this temperature, but the oxygen uptake of G. pulex is so low that the differences between infected and uninfected individuals were too small to be detected. The parasite has a direct effect upon the physiological processes of the host, but neither the mechanism of this nor the reasons for the different effects found in different host-parasite systems are yet understood. Despite the pronounced effect of P. laevis on respiration of individual hosts, its effect upon the oxygen consumption of a natural host population is small since only a small proportion of the population carries infections and water temperatures remain below 10°C for over half the year.

scholarly journals Effect of Captopril on Serum Lipid Levels and Cardiac Mitochondrial Oxygen Consumption in Experimentally-Induced Hypercholesterolemia in Rabbits

2011 ◽  
pp. S177-S184 ◽  
Author(s):  
Z. KOJIC ◽  
K. GOPCEVIC ◽  
D. MARINKOVIC ◽  
G. TASIC
Keyword(s):  
Oxygen Consumption ◽  
Serum Lipid ◽  
Respiratory Control ◽  
Adenosine Diphosphate ◽  
Lipid Levels ◽  
Mitochondrial Oxygen Consumption ◽  
Respiration Rates ◽  
Serum Lipid Levels ◽  
Hypercholesterolemic Diet ◽  
Oxygen Ratio

Angiotensin converting enzyme inhibitors are widely used in therapy of cardiovascular diseases. However, the consensus on effects of these inhibitors in control of myocardial oxygen consumption during the process of experimental hypercholesterolemia and under the condition of endothelial dysfunction has not been reached. Here we examined effects of captopril, an angiotensin converting enzyme inhibitor, on serum lipid levels and oxygen consumption rate in mitochondria isolated from heart of rabbits treated by hypercholesterolemic diet. During the twelve-week period, the Chinchilla male rabbits were daily treated by saline (controls); 1 % cholesterol diet; 5 mg/kg/day captopril or 1 % cholesterol + 5 mg/kg/day captopril. Total- and high-density lipoprotein cholesterol and triglyceride in serum were measured spectrophotometricly. The left ventricle mitochondrial fraction was isolated and myocardial oxygen consumption was measured by Biological Oxygen Monitor. Mitochondria isolated from hearts of rabbits exposed to hypercholesterolemic diet showed significantly reduced respiration rates (state 3 and state 4) with altering adenosine diphosphate/oxygen ratio, whereas the respiratory control ratio was not affected when compared to controls. Mitochondria from cholesterol/captopril–treated animals showed significantly reduced respiration rates without altering adenosine diphosphate/oxygen ratio index or respiratory control ratio. Although captopril did not exert the favorable effect on serum lipid levels in cholesterol-treated animals, it restored the mitochondrial oxygen consumption. Further studies should be performed to define the underlying physiological and/or pathophysiological mechanisms and clinical implications.

Some Factors Affecting the Oxygen Consumption of Asellus

1960 ◽  
Vol 37 (4) ◽  
pp. 706-718
Author(s):  
R. W. EDWARDS ◽  
M. A. LEARNER
Keyword(s):  
Oxygen Consumption ◽  
Dissolved Oxygen ◽  
Constant Volume ◽  
Asellus Aquaticus ◽  
Dissolved Oxygen Concentration ◽  
Factors Affecting ◽  
Consumption Rates ◽  
Rate Of Oxygen Consumption ◽  
Wet Weight ◽  
Males And Females

1. The oxygen-consumption rates of Asellus aquaticus (males and females) have been measured at 10 and 20° C. using a constant-volume respirometer, and the effect of starvation for 24 hr. investigated. The oxygen consumption is approximately proportional to the 0.7 power of the wet weight. The rate of oxygen consumption at 20° C. is greater than at 10° C. by a factor of 1.5. 2. The oxygen-consumption rates of A. aquaticus and A. meridianus have been measured at 20° C. in a flowing-water respirometer employing a polarographic technique for the measurement of dissolved-oxygen concentrations. The oxygen consumptions of A. aquaticus and A. meridianus are similar and decrease by 15-20% when the dissolved-oxygen concentration falls from 8.3 to 1.5 p.p.m. 3. The oxygen consumption of A. aquaticus is between 35 and 75% higher in the polarographic respirometer than in the constant-volume respirometer.

scholarly journals Color, chlorophyll a , and suspended solids effects on Secchi depth in lakes: implications for trophic state assessment

2019 ◽  
Vol 29 (3) ◽  
Author(s):  
Patrick L. Brezonik ◽  
R. William Bouchard ◽  
Jacques C. Finlay ◽  
Claire G. Griffin ◽  
Leif G. Olmanson ◽  
...  
Keyword(s):  
Chlorophyll A ◽  
Trophic State ◽  
Suspended Solids ◽  
Secchi Depth ◽  
State Assessment

scholarly journals Phosphorescence quenching microrespirometry of skeletal muscle in situ

2011 ◽  
Vol 300 (1) ◽  
pp. H135-H143 ◽  
Author(s):  
Aleksander S. Golub ◽  
Michael A. Tevald ◽  
Roland N. Pittman
Keyword(s):  
Skeletal Muscle ◽  
Oxygen Consumption ◽  
Initial Slope ◽  
Phosphorescence Quenching ◽  
Factors Affecting ◽  
External Sources ◽  
Disappearance Curve ◽  
Residual Blood ◽  
532 Nm

We have developed an optical method for the evaluation of the oxygen consumption (V̇o2) in microscopic volumes of spinotrapezius muscle. Using phosphorescence quenching microscopy (PQM) for the measurement of interstitial Po2, together with rapid pneumatic compression of the organ, we recorded the oxygen disappearance curve (ODC) in the muscle of the anesthetized rats. A 0.6-mm diameter area in the tissue, preloaded with the phosphorescent oxygen probe, was excited once a second by a 532-nm Q-switched laser with pulse duration of 15 ns. Each of the evoked phosphorescence decays was analyzed to obtain a sequence of Po2 values that constituted the ODC. Following flow arrest and tissue compression, the interstitial Po2 decreased rapidly and the initial slope of the ODC was used to calculate the V̇o2. Special analysis of instrumental factors affecting the ODC was performed, and the resulting model was used for evaluation of V̇o2. The calculation was based on the observation of only a small amount of residual blood in the tissue after compression. The contribution of oxygen photoconsumption by PQM and oxygen inflow from external sources was evaluated in specially designed tests. The average oxygen consumption of the rat spinotrapezius muscle was V̇o2 = 123.4 ± 13.4 (SE) nl O2/cm3·s ( N = 38, within 6 muscles) at a baseline interstitial Po2 of 50.8 ± 2.9 mmHg. This technique has opened the opportunity for monitoring respiration rates in microscopic volumes of functioning skeletal muscle.

scholarly journals Water quality in Lake Xochimilco, Mexico: zooplankton indicators and Vibrio cholerae

2015 ◽  
Author(s):  
Sarma Nandini ◽  
Pedro Ramirez García ◽  
S.S.S. Sarma
Keyword(s):  
Water Quality ◽  
Vibrio Cholerae ◽  
Chlorophyll A ◽  
Local Population ◽  
Secchi Depth ◽  
Treatment Plant ◽  
Nitrogen And Phosphorus ◽  
Physico Chemical ◽  
Eutrophic Water ◽  
Depth Water

<p>Lake Xochimilco is a eutrophic water body in Mexico City used by the local population for aquaculture and agriculture. Water level is maintained with inputs of partially treated waste water from the Cerro de la Estrella treatment plant. In this study we analysed the water quality at two sites of Lake Xochimilco, Lake Xaltocan and the Santa Cruz Canal using various indicators such as zooplankton diversity, saprobic indices, bacterial concentrations and physico-chemical variables. Eighty litres of water was filtered from Lake Xochimilco from each site, once a month from March to October of 2012, and the rotifers, cladocerans and copepods were enumerated and identified. Physico-chemical parameters such as temperature, pH, Secchi depth, water depth, nitrogen and phosphorus and chlorophyll a concentrations, and bacterial densities were measured. During the study we recorded 33 species of rotifers, the most abundant being <em>Brachionus angularis</em>, <em>B. calyciflorus</em> and <em>B. havanaensis</em>.  Among the microcrustaceans the most abundant were the cladoceran <em>Moina micrura</em> and the copepods <em>Acanthocyclops americanus</em> and <em>Arctodiaptomus dorsalis</em>. The species diversity was around 2 bits/ind. and the saprobic index between 1.5-2.0, indicating that both sites were β meso-saprobic.  At both sites nitrogen was &lt;1 mg/L and phosphorus ranged between 2.5-7.8 mg/L. Chlorophyll a concentrations were between 66-136 µg/L. The toxigenic (<em>Vibrio cholerae </em>No-O1/No-O139) and the non-toxigenic (<em>Vibrio cholerae </em>No-O135) strains of the bacterium were recorded, closely associated with littoral rotifers and cladocerans particularly <em>Brachionus quadridentatus</em> and  <em>Alona</em> sp. All variables indicate that these sites in Lake Xochimilco are eutrophic and highly contaminated and that the water quality needs to be improved.<strong></strong></p>

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