Landscape heterogeneity influences carbon dioxide production in a young boreal reservoir

2012 ◽  
Vol 69 (3) ◽  
pp. 447-456 ◽  
Author(s):  
Soren M. Brothers ◽  
Paul A. del Giorgio ◽  
Cristian R. Teodoru ◽  
Yves T. Prairie
Keyword(s):  
Carbon Dioxide ◽  
Water Column ◽  
Landscape Heterogeneity ◽  
Carbon Dioxide Production ◽  
Respiration Rates ◽  
Benthic Respiration ◽  
Sediment Respiration ◽  
Rate Of Decline ◽  
The Individual ◽  
Water Column Respiration

Surface carbon dioxide (CO2) emissions exhibit a high degree of spatial heterogeneity in the young boreal Eastmain-1 hydroelectric reservoir, located in northern Quebec, Canada. Estimates of the individual components of net CO2 production within the reservoir (benthic respiration, water column respiration, and primary production) furthermore provide a link between the heterogeneity in surface CO2 emissions and the flooded landscapes below. Specifically, the preflood carbon stock and soil–sediment respiration rates of flooded landscapes were found to influence benthic CO2 production, the rate of decline of hypolimnetic dissolved organic carbon (DOC), and the estimated rate at which flooded landscapes release DOC, further influencing water column respiration rates. Estimates of the individual components of net CO2 production in Eastmain-1 are supported by a positive relationship (t test, r2 = 0.64, P < 0.01) between measured surface CO2 emissions (mean ± SE = 1540 ± 145.4 mg C·m–2·day–1) and independently derived estimates of total net CO2 production (mean ± SE = 1230 ± 162.4 mg C·m–2·day–1). Our findings emphasize the utility of fundamental landscape characterization prior to construction in predicting reservoir greenhouse gas emissions.

PHYSIOLOGICAL CHANGES DURING MATURATION OF NEW MEXICAN-TYPE PEPPERS

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 623d-623
Author(s):  
Marisa M. Wall ◽  
Charles L. Biles
Keyword(s):  
Carbon Dioxide ◽  
Chlorophyll Content ◽  
Carbon Dioxide Production ◽  
Fruit Firmness ◽  
Physiological Changes ◽  
Galactosidase Activity ◽  
New Mexican ◽  
Respiration Rates ◽  
Chile Peppers ◽  
Beta Galactosidase

New Mexican chile peppers were harvested at weekly intervals beginning 105 days after planting (DAP), and evaluated for ethylene (C2H4) production, respiration rates, chlorophyll content, beta-galactosidase activity, polygalacturonase (PG) activity, and fruit firmness. Physiological changes were most apparent in peppers harvested 139-154 DAP. Beta-galactosidase activity increased rapidly beginning 147 DAP, and reached a peak of 24.5 mmol·gfw-1 when peppers were harvested 160 DAP. Polygalacturonase was not detectable at any stage of maturation. Fruit firmness was greatest (35.8 N) at 139 DAP and decreased significantly at 160 DAP. Carbon dioxide production and chlorophyll content were highest in young pods harvested 105 DAP, and decreased steadily thereafter. Ethylene production peaked (0.185-0.202 nl·gfw-1·h-1) in peppers harvested between 146-154 DAP.

scholarly journals Time-dependent Changes in the Longitudinal Sugar and Respiratory Profiles of Asparagus Spears During Storage at 0 °C

2014 ◽  
Vol 139 (4) ◽  
pp. 339-348 ◽  
Author(s):  
Sven Verlinden ◽  
Silvanda M. Silva ◽  
Robert C. Herner ◽  
Randolph M. Beaudry
Keyword(s):  
Carbon Dioxide ◽  
Respiration Rate ◽  
Carbon Dioxide Production ◽  
Time Dependent ◽  
Asparagus Officinalis ◽  
Rapid Decline ◽  
Cell Wall Biosynthesis ◽  
Glucose Depletion ◽  
Rate Of Decline ◽  
Sugar Levels

The rate of respiration and the concentrations of sucrose, glucose, and fructose were measured along the length of intact asparagus (Asparagus officinalis cv. Jersey Giant) spears during storage at 0 °C. Carbon dioxide production by each of five sections along the spear was initially high but underwent a rapid and extensive decline within the first 24 hours after harvest with the rate of decline slowing thereafter. The respiration rate was highest at the tip (Section 1), decreasing as the distance from the tip increased (Sections 2 through 5 with Section 5 being more basal). Initially, the respiration rate of the tip was approximately four times that of the base, but after 23 days at 0 °C, the respiration rate of the tip was only twice that of the base. Sugar levels were measured in Sections 1 through 4. Sugar levels declined with time, but increased, unlike respiration, with distance from the tip. Sucrose underwent a rapid decline within the first 24 hours of storage in the tip and Sections 3 and 4. Sucrose depletion was most extensive in the tip, reaching more than 95% by Day 23. Glucose underwent the most rapid decline in Section 2. The relatively higher rate of glucose depletion in Section 2, the zone of rapid cell elongation, may have been to support a relatively higher rate of cell wall biosynthesis in this section. For the first day after harvest, sugar depletion far outstripped hexose equivalents respired as CO2. Afterward, however, the rate of respiration (as hexose equivalents) was similar to the rate of sugar depletion for all sections except the most basipetal, which lost carbohydrate faster than could be accounted for by respired CO2. The data suggest that hexoses were exported from more basipetal tissues to support the metabolic activity of more acropetal sections.

scholarly journals THE RESPIRATORY RATE OF THE SCIATIC NERVE OF THE FROG IN REST AND ACTIVITY

1919 ◽  
Vol 1 (6) ◽  
pp. 613-621 ◽  
Author(s):  
A. R. Moore
Keyword(s):  
Carbon Dioxide ◽  
Sciatic Nerve ◽  
Nerve Impulse ◽  
Carbon Dioxide Production ◽  
The Other ◽  
Sartorius Muscle ◽  
Indicator Method ◽  
The Individual ◽  
The Brain ◽  
Stimulation Of

1. With the indicator method of Haas, the rates of carbon dioxide production have been measured in the case of the sciatic nerve, various parts of the brain, and the sartorius muscle of the frog. The rate of respiration of the sciatic nerve is from 10 to 30 per cent of that of the other tissues, varying somewhat with the individual. 2. Stimulation of the sciatic nerve with induction shocks sufficient to induce tetanus of the muscle does not increase the output of carbon dioxide from the sciatic nerve, even if continued as long as 30 minutes. Sartorius muscle used as a control showed a marked increase in carbon dioxide production upon relaxation after contraction resulting from such stimulation. 3. These facts indicate that the nerve impulse does not depend upon processes leading to the production of carbon dioxide.

scholarly journals Ethylene and Carbon Dioxide Production in Detached Fruit of Selected Pepper Cultivars

1999 ◽  
Vol 124 (4) ◽  
pp. 402-406 ◽  
Author(s):  
Lucia Villavicencio ◽  
Sylvia M. Blankenship ◽  
Douglas C. Sanders ◽  
William H. Swallow
Keyword(s):  
Carbon Dioxide ◽  
Ethylene Production ◽  
Carbon Dioxide Production ◽  
King Arthur ◽  
Ethylene Evolution ◽  
Green Fruit ◽  
Respiration Rates ◽  
Maturity Stages ◽  
Hot Peppers ◽  
Bell Peppers

Bell peppers (Capsicum annuum L.) are classified as nonclimacteric fruits while some hot peppers have been reported as climacteric. Responses of peppers to exogenously applied ethylene-releasing compounds suggest ethylene involvement in the ripening process. Ethylene production and respiration rates in 13 cultivars of pepper: `Camelot', `Cherry Bomb', `Chiltepin', `Cubanelle', `Banana Supreme', `Habanero', `Hungarian Wax', `Mesilla', `Mitla', `Savory', `Sure Fire', `Tabasco', and `King Arthur' were studied under greenhouse and field conditions. Fruit from each cultivar were harvested at different maturity stages determined by color, ranging from mature-green to full red-ripe. Carbon dioxide and ethylene production were measured by gas chromatography. Both variables were significantly different among maturity stages for all cultivars. Respiration rates were between 16.5 and 440.3 mg·kg-1·h-1 CO2. Ethylene production ranged from 0.002 to 1.1 μL·kg-1·h-1. Two patterns of CO2 production were identified: higher CO2 production for mature-green fruit with successive decreases for the rest of the maturity stages or lower respiration rates for mature-green fruit with an increase in CO2 production either when fruit were changing color or once fruit were almost totally red. A rise in CO2 production was present for most cultivars. Ethylene evolution increased significantly at maturity or before maturity in all cultivars except `Cubanelle' and `Hungarian Wax'. Respiration rates and ethylene production were significantly different among cultivars at the mature-green and red stages.

Metabolism during normoxia, hyperoxia, and recovery in newborn rats

1992 ◽  
Vol 70 (3) ◽  
pp. 408-411 ◽  
Author(s):  
Peter B. Frappell ◽  
Andrea Dotta ◽  
Jacopo P. Mortola
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Consumption ◽  
Metabolic Rate ◽  
Carbon Dioxide Production ◽  
Oxygen Availability ◽  
Aerobic Metabolism ◽  
Newborn Rats ◽  
Ambient Temperatures ◽  
Positive Effects

Aerobic metabolism (oxygen consumption, [Formula: see text], and carbon dioxide production, [Formula: see text]) has been measured in newborn rats at 2 days of age during normoxia, 30 min of hyperoxia (100% O2) and an additional 30 min of recovery in normoxia at ambient temperatures of 35 °C (thermoneutrality) or 30 °C. In normoxia, at 30 °C [Formula: see text] was higher than at 35 °C. With hyperoxia, [Formula: see text] increased in all cases, but more so at 30 °C (+20%) than at 35 °C (+9%). Upon return to normoxia, metabolism readily returned to the prehyperoxic value. The results support the concept that the normoxic metabolic rate of the newborn can be limited by the availability of oxygen. At temperatures below thermoneutrality the higher metabolic needs aggravate the limitation in oxygen availability, and the positive effects of hyperoxia on [Formula: see text] are therefore more apparent.Key words: neonatal respiration, oxygen consumption, thermoregulation.

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