Average Respiration Rate Research Articles

Winter soil CO2 efflux and its contribution to annual soil respiration in different ecosystems of Ebinur Lake Area

Arid and semiarid areas account for about one-third of the total land surface, and which play an important role in the global carbon cycle and climate system. However, up to now, compare with plenty knowledge information on winter soil efflux of forest ecosystems in mid-latitude ecosystems, winter soil efflux of arid areas at mid-latitude ecosystems is scare, Ebinur Lake Area, which is the study area of the present study, is located in arid regions of Northern China, with a vulnerable ecological environment suffering from extreme weather and climate. The objectives of this study were: (1) measure the winter soil respiration rate in our study area and determine its major environmental factors; (2) determine the winter soil CO2 efflux and its contribution to annual soil CO2 efflux in different ecosystems; and (3) discuss the estimated method of soil respiration that is most suitable to arid areas. We measured winter soil CO2 efflux and the associated environment factors in a farmland ecosystem (50a and 9a cotton fields), an abandoned land ecosystem (7a and 3a abandoned lands) and desert ecosystem (Populus euphratica, Phragmites australis communities and sandy desert) in Ebinur Lake Area, China. The average winter soil respiration rate in the arid areas in the mid-latitude was 0.063 μmol m−2 s−1 to 0.730 μmol m−2 s−1. Specifically, the average winter soil respiration rate in the farmland ecosystems, abandoned land ecosystems and desert ecosystems were 0.686 μmol m−2 s−1, 0.443 μmol m−2 s−1 and 0.276 μmol m−2 s−1, respectively. Range of annual Q10 (known as the increase in soil respiration rate per 10°C increase in temperature) in the three ecosystems were 0.989 to 4.962, 1.971 to 2.096 and 0.947 to 5.173, respectively. The relatively higher Q10 values in the different ecosystems were all obtained in winter. We found that water (in the form of soil moisture or atmospheric humidity) was the primary factor that affected the change of soil respiration rate in the winter. Winter soil CO2 efflux were 9 g C m−2 to 132 g C m−2 and 19 g C m−2 to 130 g C m−2 by the observed and modelled method for soil respiration, respectively. The average winter soil CO2 efflux were 79.4 and 78.7 g C m−2, reLspectively. The contributions of winter soil CO2 efflux to annual one were 4% to 31% and 4% to 30%. In the study area, the model using the observed ecosystem-specific response equations between soil respiration and water-temperature simulated the soil respiration rate was the most suitable ones.

High dietary selenium and vitamin E supplementation ameliorates the impacts of heat load on oxidative status and acid-base balance in sheep1,2

The objective of this study was to determine the efficacy of supranutritional dietary selenium and vitamin E (Vit E) to ameliorate the effect of heat stress (HS) on oxidative status and acid-base balance in sheep. Thirty-two Merino × Poll Dorset ewes were acclimated to indoor individual pen feeding of a pelleted control diet (0.24 g Se and 10 IU of Vit E/kg DM) for 1 wk. Sheep were then moved to metabolism cages in climatic chambers and randomly allocated to a 2 × 2 × 2 factorial design with the respective factors being dietary Se (0.24 and 1.20 mg/kg DM as Sel-Plex; Alltech, Australia), Vit E (10 and 100 IU/kg DM), and temperature for 2 wk. After 1 wk of acclimation in metabolic cages, 1 climatic chamber continued on thermoneutral (TN) conditions (18°C to 21°C and 40% to 50% relative humidity [RH]), and the other one was set to HS conditions (28°C to 40°C and 30% to 40% RH) for 1 wk. The sheep were then returned to individual pens and fed the control diet for 1 wk before being returned to the same diet as in the first period but a reversed thermal treatment for a further 2 wk. Physiological parameters were recorded 3 times daily, and blood samples were collected on d 1 and 7 of thermal treatment. Average respiration rate and rectal temperature of sheep were increased (P < 0.001) during HS; however, combined supranutritional supplementation of Se and Vit E reversed the effects of HS. Sheep given the high Se and high Vit E diet had a lower respiration rate (191 vs. 232 breaths/min; P = 0.012) and rectal temperature (40.33°C vs. 40.58°C; P = 0.039) under peak HS (1700 h) compared with those fed the low Se and low Vit E diet. Plasma reactive oxygen metabolites concentrations were reduced (P = 0.048) by 20%, whereas biological antioxidant potential was increased (P = 0.17) by 10% in sheep fed the high Se and high Vit E diet compared with those fed the low Se and low Vit E diet. Blood pH was elevated (P = 0.007) and bicarbonate was reduced (P = 0.049) under HS, and again, these effects were ameliorated by the high Se and high Vit E diet. Both white blood cell glutathione peroxidase gene expression and red blood cell lysate glutathione peroxidase activity were increased in sheep fed the high Se and high Vit E diet. These data suggest that supranutritional dietary Se or Vit E can reduce some of the negative effects of HS. However, the synergism between the 2 antioxidants improves their potential to ameliorate the impacts of HS in sheep.

Exhaled breath condensate hydrogen peroxide concentration, a novel biomarker for assessment of oxidative stress in sheep during heat stress

The present study aimed to measure hydrogen peroxide (H2O2) in exhaled breath condensate (EBC) as an index of oxidative stress induced by heat stress (HS) and to evaluate the antioxidant potential of supranutritional levels of selenium (Se) and vitamin E under HS conditions in sheep. Thirty-two Merino × Poll Dorset ewes (in two replicates) were acclimated to indoor individual pen feeding of a pelleted control diet (0.24 g Se and 10 IU of vitamin E/kg DM) for 1 week. Sheep were then randomly allocated to a 2 × 2 factorial design with the respective factors being dietary Se (0.24 and 1.20 mg/kg DM as Sel-Plex) and vitamin E (10 and 100 IU/kg DM) for 2 weeks. After 1 week acclimation to the diets the sheep were placed in metabolism cages in one of two climatic chambers set to either thermoneutral (18−21°C and 40–50% relative humidity) or HS (28−40°C and 30–40% relative humidity) conditions for 1 week. Average respiration rate and rectal temperature were increased (P &lt; 0.001) during HS. Similarly, H2O2 concentration in EBC and plasma reactive oxygen metabolites were increased significantly (P = 0.041 and P = 0.002, respectively), in sheep exposed to HS. The EBC H2O2 concentration was reduced (P &lt; 0.05) in sheep fed the diet supplemented with supranutritional levels of both Se and vitamin E. Sheep supplemented with antioxidants also had lower respiration rates (191 vs 232 breaths/min, P = 0.012) and rectal temperature (40.33 vs 40.58°C, P = 0.039) under peak HS (1300 hours and 1700 hours) compared with those on the control diet indicating an improved capacity to handle HS. These data suggest that the H2O2 concentration in EBC can be utilised as a novel biomarker to demonstrate oxidative stress induced by HS in sheep.

Effects of Breathing Practice in Vinyasa Yoga on Heart Rate Variability in University Students- A Pilot Study

Objective: This pilot study investigated the effects of the breathing practice in vinyasa yoga on heart rate variability (HRV) in university students. High HRV is correlated with decreased anxiety and improved performance. It was hypothesized that after yoga HRV would increase and heart rate (HR) would decrease. Design: Thirteen students were enrolled into a 10-week yoga program and asked to attend at least 3 yoga classes. Before and after each class, the students’ HRV was measured. Respiration rate was measured before and after half of the classes that each student attended. Each participant’s measures were compared pre and post yoga sessions, and statistical differences or trends in the data were evaluated. Setting: The study was performed in the Campus Recreational Center, University of Arizona. Results: For students who attended 3 yoga sessions, HRV was greater after each session than before the session, reaching statistical significance for sessions 1 and 3. Heart rate variability in the low frequency range (LF power) significantly increased after the third session compared to baseline (before first session). Heart rate did not significantly change. Average respiration rate after the last session each student attended was significantly lower than before the session. Conclusion: Students experience increased HRV and decreased respiration rate after yoga sessions, consistent with relaxation and an increased ability to handle stress. Running Head: Vinyasa Yoga and Heart Rate Variability

Identification of SNP in HSP90AB1 and its Association with the Relative Thermotolerance and Milk Production Traits in Indian Dairy Cattle

Heat shock proteins (Hsp) play crucial role in cellular thermotolerance and heat stress response. In the present work, Allele specific PCR (AS-PCR) was standardized to detect the nucleotide polymorphism within the HSP90AB1 gene (SNP g.4338T>C) in Indian breeds of dairy cattle. The identified genotypes were associated with relative thermotolerance in terms of physiological parameters and milk production traits. The results of the experiments revealed that the genotype frequency of CC, CT, and TT for Sahiwal were 0.05, 0.78, and 0.17, respectively, and in Frieswal, the frequencies were 0.20, 0.70, and 0.10, respectively. The average rectal temperature (ART) and average respiration rates (ARR) were recorded during peak summer stress and heat tolerance coefficient (HTC) was calculated. The association studies indicated that TT genotypes had significantly (P < 0.01) higher HTC and lower ARR values than CT and CC in both the breeds. The TT genotype animals also had better production parameter in terms of total milk yield (TMY) (P < 0.01). These findings may partly suggest the role of HSP90AB1 polymorphisms in the regulation of heat stress response and consequent effect on production traits. Nevertheless, involvement of other regulatory mechanisms cannot be overruled.

Physiological and haemato-biochemical profiling of domestic geese (Anser anser domesticus) of Kashmir

Area-specific profiling of physiological and biochemical parameters in different species is prerequisite for establishing reference values valid for clinical practice. The present study was aimed at physiological, haematological and biochemical profiling of domestic geese of Kashmir. The study was conducted on 30 adult domestic geese comprising of 12 male and 18 female (procured locally) which were maintained at Centre of Research on Poultry, SKUAST-Kashmir. The average body temperature, respiration rate and heart rate in geese were 40.05 ± 0.15°C, 17.16 ± 0.75 breaths min−1 and 60.57±5.09 beats min−1, respectively. Electrocardiogram (ECG) showed presence of P, QRS and T waves. The mean electrical axis/instantaneous mean vector ranged from -86 to -95o indicating its orientation along the long axis of body and superior to frontal plane. The amplitude of QRS wave was almost similar and highest in lead II and III, whereas lead I could hardly represent voltages of QRS wave. The voltage in QRS wave ranged from 0.9 to 1.3 mv. The mean hemoglobin, ESR, PCV, TEC, MCV, MCH, MCHC and TLC was 11.5 ± 0.2 mg dL−1, 0.1 ± 0.17 mm hr−1, 50.08 ± 1.81%, 3.06 ± 0.78 x 106 mm3, 166.13 ± 5.35 m3, 38.25 ± 1.26 pg, 23.14 ± 0.50% and 67.01 ± 4.08 x 103 mm3, respectively. The differential leukocyte count revealed overall mean of 89.27 ± 1.36, 7.77 ± 1.30, 2.95± 0.45 and 0.0% heterophils, lymphocytes, monocytes and basophils, respectively. The blood glucose, total protein, cholesterol-LS and HDL-cholesterol levels were 216.3 ± 5.5 g dL−1, 21.59 ± 1.29 g L−1, 123.0 ± 10.4 mg dL−1 and 29.04 ± 2.24 mg dL−1, respectively. Gender-wise, only heart rate and body temperature showed a significant difference. The present study established basic physiological and haemato-biochemical indices of Kashmir geese.

施肥方式对紫色土土壤异养呼吸的影响

Recent studies have shown that soil respiration is the critical importance in determining the carbon balance of terrestrial ecosystems. Respiration from soils is comprised of both the heterotrophic respiration of microorganisms( soil bacteria,fungi,and fauna) and autotrophic respiration from roots and mycorrhizae. Precise assessment of these components is important for calculating the carbon budgets of vegetation and the turnover rate of soil organic matter,as well as for understanding sources and sinks of carbon in terrestrial ecosystems in the face of global climate change. Although soil heterotrophic respirations have received considerable attention in recent decades,much less is known about the effects of various natural or artificial factors such as temperature,precipitation or fertilization etc. on it. The field study was conducted at a sloping cropland in Yanting Agro-ecological Station of Purple Soil,Chinese Academy of Science under Chinese Ecosystem Research Network( CERN),situated at N31°16°,E105°28',with the altitude of 400 to 600 meters in the middle of Sichuan Basin,where a set of long-term research plots is located. Three plots were randomly assigned to oneof the following treatments: conventional chemical fertilizer( NPK),organic manure( pig slurry,OM) and crop residue with chemical fertilizer( RSDNPK). Total nitrogen for each fertilization treatment was applied at the same rate with 130 and150 kgN /hm2 for wheat and maize seasons,respectively. The results showed that soil heterotrophic respiration exhibited pronounced seasonal variations that clearly reflected those of soil temperature,with minimum values in winter and maximum values in summer. There was a pulse of soil heterotrophic respiration induced by fertilization at the 5th day after fertilization. The peak rate for OM treatment was 2356. 8 mgCO2m-2h-1and it was significantly higher than that for both RSDNPK and NPK treatments( P0. 01). Meanwhile,the respiration rate and the annual cumulative CO2 emission in OM and RSDNPK treatments were higher than those in NPK treatment. During wheat growing season,average respiration rate for NPK,OM and RSDNPK treatments were 212. 9,285. 8 and 305. 8 mgCO2m-2h-1,respectively,which were all lower than that in maize growing season. The cumulative soil CO2 emissions from NPK,OM and RSDNPK were 255. 1,342. 3and 369. 5 gC /m2 for wheat season,and 344. 7,542. 8 and 376. 9 gC /m2 for maize season,while 599. 8,885. 1 and 746. 4gCm-2for the whole year,respectively. The results implied that lower C /N ratio organic material was the primary driving force for increasing soil heterotrophic rate and cumulative soil CO2 emissions. The values of temperature sensitivity( Q10)for soil heterotrophic respiration in wheat season and maize season were also measured. The results showed that Q10 values in wheat season always higher than that in maize season at all plots. During the whole experiment time,the magnitudes of Q10 both followed the order of OM NPK RSDNPK,which was clearly reflected that Q10 was sensitive to lower C /N organic materials. Q10 values obtained from soil temperature at soil surface( 0 cm) and soil 5 cm depth in OM and RSDNPK were2. 64,2. 77 and 1. 88,1. 99,respectively. It indicated that the Q10 values for soil heterotrophic respiration rates were higher at lower temperatures and lower at higher temperature.

Effects of Radix Bupleuri extract supplementation on lactation performance and rumen fermentation in heat-stressed lactating Holstein cows

Radix Bupleuri extract (RBE) has been shown to mitigate negative effects of high ambient temperature. This experiment was conducted to investigate effects of RBE supplementation on lactation performance and rumen fermentation in Holstein cows under heat stress. Forty Holstein cows (75±15d in milk, 37.5±1.8kg of milk/d, and 1.7±0.4 parity) were randomly assigned to one of four groups (n=10). One of four treatment diets, assigned randomly to one of four groups, consisted of RBE supplementation at 0, 0.25, 0.5 or 1.0g/kg of the basal diet (concentrate and roughage) based on dry matter (DM). Cows were housed in a tie-stall barn and were individually fed the treatment diets. The experiment lasted for 10wk in hot summer. During the experiment, average ambient temperatures and temperature-humidity indexes (THI) were respectively 27.5±1.5, 29.8±1.9 and 28.1±1.7°C, and 78.2±2.7, 79.8±3.3 and 78.3±3.4 at 0600, 1400 and 2200h. Average respiration rates (RR) with RBE at 0.25, 0.50 and 1.0g/kg were 65.6, 60.3 and 67.4, respectively, vs. 71.4 (breaths/min) for the control (P<0.01). Average rectal temperatures (RT) were 39.1, 39.0 and 39.1 vs. 39.3°C for the control (P<0.01). Moreover, cows supplemented with RBE increased dry matter intake (DMI, 22.8, 21.6 and 22.1 vs. 20.9kg/d) (P<0.05) and milk production (34.2, 33.4 and 32.4 vs. 31.6kg/d) (P<0.01) compared with control. Percentages of milk protein and fat were similar among groups, while milk protein yield increased with increasing level of RBE (0.97, 0.95 and 0.92 vs. 0.89kg/d for the control) (P<0.01). Milk fat yield also increased with RBE (1.13, 1.12 and 1.09 vs. 1.02kg/d for the control) (P<0.05). There was no treatment effect on diet apparent digestibility or volatile fatty acid (VFA) concentration among groups. Overall, supplemental RBE at 0.25 or 0.5g/kg could mitigate the negative effects of heat stress on production in lactating Holstein cows.

干湿交替频率对不同土壤CO2和N2O释放的影响

干旱、半干旱和地中海气候区,乃至一些湿润地区,由干湿交替引起的土壤碳、氮的短暂脉冲式释放很大程度上决定着长时间尺度温室气体释放的总量,是土壤碳、氮温室气体释放的关键过程。选择我国降雨梯度下的森林、农田、草地和荒漠生态系统,采集土样进行实验室统一控制条件下的多重干湿交替循环,对比探讨不同生态系统土壤干湿交替频率对CO₂和N₂O释放的影响模式。结果表明:(1)干湿交替能够显著的激发土壤中CO₂和N₂O的释放,森林、农田、草地和荒漠土壤CO₂和N₂O释放速率对干湿交替的响应模式基本一致,其响应强度与土壤本底中碳和氮的含量有关;(2)在一定培养时间内,随着干湿交替频率的增加,土壤再湿润阶段CO₂释放速率降低,但是,气体释放的总量较之于恒湿对照组有所增加。(3)不同土壤N₂O的释放总量对干湿交替频率的响应模式表现出很大的差异,其中农田和荒漠土壤响应模式类似。;In the context of climate change impacts on the rainfall patterns, understanding the effects of soil drying-rewetting cycles on green-house gas emission has become increasingly important in many ecosystems. Soil carbon and nitrogen releases caused by drying and rewetting cycles largely determine the total amount of greenhouse gases emission for a long time in an ecosystem. Such kind of influence is particularly important in arid, semi-arid and Mediterranean regions. The soil drying-rewetting cycle is a natural phenomenon that the soil experiences drying, then wetting, and then drying and rewetting again and again. When a dry soil is being rewetted, the amount of soil microbial biomass and its activity can be sharply increasing in a short time period, and then a large amount of gaseous carbon (C) and nitrogen (N) erupts from the soil. The sudden release of gaseous C and N is caused by the stimulation of the soil microbes. Such a phenomenon is called Birch effect. The drying-rewetting cycles play an important role in the feedbacks of terrestrial ecosystems. In this study, soil samples were taken from four field sites of forest, agriculture, grassland and desert ecosystems along the precipitation gradient in China. These four sites are Beijing Forest Ecosystem Study, Ansai Agricultural Ecosystem Study, Inner Mongolia Grassland Study and Fukang Desert Ecosystem Study sites of the Chinese Ecosystem Research Network (CERN). Based on the laboratory experiment with 0, 2, 5, 7 and 14 drying-rewetting cycles in the controlling temperature, we examed the patterns of drying-rewetting impacts on soil CO₂ and N₂O emission. Our results showed that: (1) Drying and rewetting cycles significantly stimulated the CO₂ and N₂O releases from soil. For example, in comparison with the control experiment with constant soil moisture in the grassland soil, the average respiration rate of 14-cycle,7-cycle,5-cycle and 2-cycle treatments increased 43%、103%、116% and 192%, respectively. We also found that response patterns in CO₂ and N₂O release rates to drying and rewetting frequencies were similar among different ecosystem soils. The initial rewetting pulses were the highest, and then declined over time. (2) The total amount of CO₂ released from the cycling soil was higher than that from its corresponding control treatment with constant soil moisture. In the forest soil, the 14-cycle soil released a total of 360.11μg C-CO₂/g soil in comparison with the control treatment with constant soil moisture, which released 284.56 μg C-CO₂/g soil. The cycling increased respiration by 27%. In the grassland soil, the 14-cycle soil released a total of 339.88μg C-CO₂/g soil in comparison with the control treatmen, which released 244.01 μg C-CO₂/g soil, increased by 39%. In the agriculture soil, the 14-cycle soil released a total of 299.31μg C-CO₂/g soil in comparison with the control treatment, which released 143.27 μg C-CO₂/g soil, increased respiration by 109%. In the desert soil, the 14-cycle soil released a total of 167.54μg C-CO₂/g soil in comparison with the control treatment, which released 142.79 μg C-CO₂/g soil, increased respiration by 17%. (3) Cumulative N₂O release among different ecosystem soils had different drying-rewetting response patterns, but soils from the agriculture and desert ecosystems have similar response patterns.

Effects of nitrogen fertilizer sources and temperature on soil CO2 efflux in Italian ryegrass crop under Mediterranean conditions

We report the results of a study that aimed to assess the dynamics of total and heterotrophic soil respiration and its relationships with soil temperature or soil moisture of an Italian ryegrass haycrop managed with different nitrogen (N) fertilizer sources. The field experiment was carried out in the Nitrate Vulnerable Zone of the dairy district of Arborea, a reclaimed wetland in central-western Sardinia, Italy. This is an area characterized by sandy soils, shallow water table and intensive dairy cattle farming systems. Italian ryegrass is grown for hay production in the context of a double cropping rotation with silage maize. We analyzed the effects of N fertilizer treatments on soil carbon dioxide (CO 2 ) efflux, soil water content and soil temperature: i) farmyard manure; ii) cattle slurry; iii) mineral fertilizer; iv) 70 kg ha -1 from slurry and 60 kg ha -1 from mineral fertilizer that corresponds to the prescriptions of the vulnerable zone management plan . During the monitoring period, soil water content never fell below 8.6% vol., corresponding to approximately -33 kPa matric potential. Total and heterotrophic soil respiration dynamics were both influenced by soil temperature over winter and early spring, reaching a maximum in the first ten days of April in manure and slurry treatments. In the last 30 days of the Italian ryegrass crop cycle, total soil respiration decreased and seemed not to be affected by temperature. The analysis of covariance with soil temperature as covariate showed that average respiration rates were significantly higher under the manure treatment and lower with mineral fertilizer than the slurry and slurry+mineral treatments, but with similar rates of respiration per unit increase of soil temperature for all treatments. The average soil respiration rates were significantly and positively related to the soil carbon (C) inputs derived from fertilizers and preceding crop residuals. We concluded that: i) the fertilizer source influenced soil CO 2 efflux of the winter haycrop according to the amount of C input; and ii) that the temporal dynamics of soil respiration can be explained by soil temperature regime only in winter and early spring. These findings suggest that further studies are needed to analyze the role of soil biological factors controlling soil respiration dynamics of intensive forage cropping systems under Mediterranean conditions.

Oxygen exchange and ice melt measured at the ice-water interface by eddy correlation

Abstract. This study examined fluxes across the ice-water interface utilizing the eddy correlation technique. Temperature eddy correlation systems were used to determine rates of ice melting and freezing, and O2 eddy correlation systems were used to examine O2 exchange rates driven by biological and physical processes. The study was conducted below 0.7 m thick sea-ice in mid-March 2010 in a southwest Greenland fjord and revealed low rates of ice melt at a maximum of 0.80 mm d−1. The O2 flux associated with release of O2 depleted melt water was less than 13 % of the average daily O2 respiration rate. Ice melt and insufficient vertical turbulent mixing due to low current velocities caused periodic stratification immediately below the ice. This prevented the determination of fluxes 61 % of the deployment time. These time intervals were identified by examining the velocity and the linearity and stability of the cumulative flux. The examination of unstratified conditions through vertical velocity and O2 spectra and their cospectra revealed characteristic fingerprints of well-developed turbulence. From the measured O2 fluxes a photosynthesis/irradiance curve was established by least-squares fitting. This relation showed that light limitation of net photosynthesis began at 4.2 μmol photons m−2 s−1, and that algal communities were well-adapted to low-light conditions as they were light saturated for 75 % of the day during this early spring period. However, the sea-ice associated microbial and algal community was net heterotrophic with a daily gross primary production of 0.69 mmol O2 m−2 d−1 and a respiration rate of −2.13 mmol O2 m−2 d−1 leading to a net ecosystem metabolism of −1.45 mmol O2 m−2 d−1. This application of the eddy correlation technique produced high temporal resolution O2 fluxes and ice melt rates that were measured without disturbing the in situ environmental conditions while integrating over an area of approximately 50 m2 which incorporated the highly variable activity and spatial distributions of sea-ice communities.

小兴安岭5种林型土壤呼吸时空变异

Soil CO2 efflux(RS) is the second largest terrestrial carbon flux.Even a relatively small change in the carbon flow into,or out of,soils could have a large impact on atmospheric CO2 concentration.Conversion of forest ecosystems can potentially be a major contribution to greenhouse gas emissions.Therefore,reviewing measured rates and spatial and temporal variability of soil respiration from different terrestrial ecosystems and evaluating the effects of environmental factors and human disturbance on them provides essential data for the global carbon budget and its estimated effect on climate change.The representative disturbance gradient(virgin forest secondary forest plantation) in the Liangshui Nature Reserve of the Xiaoxing′an Mountains of Northeast China provides an excellent opportunity to examine how soil respiration responds to human disturbances.Throughout the growing season(May—October) in 2010,an infrared gas exchange analyzer was used to measure and compare soil respiration rates and related environmental factors in various forest systems.The forest systems investigated were virgin mixed broadleaved-Korean pine forest,valley spruce-fir forest,selectively cut mixed broadleaved-Korean pine forest,secondary birch forest and Dahurian larch plantation.The results showed that there was significant seasonal variation in soil respiration in the different forest types during the growing season where the peak soil respiration rate was in July and August and the lowest respiration rate was in the early and late growing season.There was a significant exponential correlation between soil respiration and soil temperature at 5 cm(T5) in the five forest types(P0.001).Furthermore,soil temperature and soil moisture and the interactions between them could explain 71% of seasonal variation in soil respiration,and incorporating soil moisture into the pure RS temperature model improved the prediction of RS in most forest types.The average soil respiration rates in the growing season for the birch,spruce-fir,selectively cut mixed broadleaved-Korean pine,mixed broadleaved-Korean pine,and larch forests were 3.59,3.52,3.44,2.58,and 2.29 μmolCO2 · m-2 · s-1,respectively and the corresponding Q10 values were 2.32,2.10,2.08,1.95,and 1.84.The average soil respiration rate of the mixed broadleaved-Korean pine forest was 33% and 28% lower than the secondary birch forest and selectively cut mixed broadleaved-Korean pine forest,respectively,but 12% higher than the larch plantation.This indicated that soil respiration responded differently to human disturbance in the mixed broadleaved-Korean pine forest.The standard deviation(SD) of RS for the six forest types showed a similar seasonal pattern to soil temperature where the mean SD of RS in the six forest types was 1.03 μmolCO2 · m-2 · s-1 between late June and early September and 0.51 μmolCO2 · m-2 · s-1 in the early and late growing season.The average coefficient of variation(CV) among forest types was 26.40%.The CV of soil respiration rate between replicates in each forest type varied from 32.13% to 60.20%,significantly greater than those between plots(14.28%—35.70%),indicating that soil respiration was more variable on the fine scale.The CV of RS between replicates in the mixed broadleaved-Korean pine forest and selectively cut mixed broadleaved-Korean pine forest(59.54% and 60.20%,respectively) were significantly(P0.05) greater than those in valley spruce-fir forest and Dahurian larch plantation(44.39% and 32.13%,respectively).Although spatial variations in soil respiration for all the forest types were not significantly related to soil temperature,soil moisture could explain about 15.8%—33.5% of spatial variation of soil respiration within each forest type except the mixed broadleaved-Korean pine forest.

Soil Respiration under Three Land use Categories of Mountainous Region in Xishuangbanna, Yunnan

In order to study the difference of the soil respiration under different land-uses in Xishuangbanna, field observations were conducted on the soil respiration rate from November 2010 to May 2011 under forest tea plantations, terrace tea plantations and secondary forests. Daily variations of soil respiration and its influence factors were analyzed. The results showed that there are different daily-change patterns of soil respiration rate and soil moisture under different land-uses, with statistically insignificance of soil respiration rate (P0.05). The daily maximum soil respiration rate is almost at 14 ∶ 00-16 ∶ 00. The soil respiration rate and soil moisture vary most during the dry- rainy transition season. The average soil respiration rate: forest tea plantations (2.62 μmol · m-2s-1)terrace tea plantations (2.73 μmol · m-2s-1)secondary forest (3.01 μmol · m-2s-1). Soil humidiy, if too high or low, will hinder the soil respiration. A strong correlation was found between soil respiration and soil moisture (0-10 cm)and daily average air temperature. Precipitation caused soil respiration large fluctuations.

Impact of device‐guided slow breathing on symptoms of chronic heart failure: a randomized, controlled feasibility study

In many patients with chronic heart failure (CHF) even normal daily life activities cause dyspnoea and fatigue, well-being might be considerably improved by even a modest decrease in such symptoms. The aim of this study was to investigate if lowering breathing rate with the help of a respiratory modulation (RM) device could improve symptoms in patients with CHF. Stable CHF patients with symptoms of dyspnoea were randomized to twice-daily 20 min sessions using an RM device or to music listening (ML) using a CD player, for a 4-week study period. Respiratory modulation guides the user to achieve a slow breathing rate (<10 breaths/min) while increasing exhalation time (Tex) relative to inhalation time (Tin). Lower breathing rate was accomplished by synchronizing respiratory movements with musical tones generated in response to breathing movements monitored with a belt-type sensor. Endpoints were reduced breathlessness and New York Heart Association (NYHA) class. Seventy-two patients (52 male, age 73 ± 11 years, NYHA 3.1 ± 0.9) were randomized and 65 completed the study (30 RM and 35 ML, respectively). There was no in-between group improvement in breathlessness and NYHA class. Patients in the RM group who displayed an average increase in Tex/Tin of >0.2 and a reduction in the average respiration rate during 30 sessions were considered responders. Responders reported reduced breathlessness (-0.86 ± 0.23 units, P < 0.005) and improved NYHA class (-0.64 ± 0.20, P < 0.01) compared with non-responders. Device-guided RM might have the potential to relieve symptoms of heart failure in outpatients by changing their breathing pattern.

Influence of Packaging on Quality Retention of Longans (Dimocarpus longan) Under Constant and Fluctuating Postharvest Temperatures

Longan (Dimocarpus longan) fruit production and global exports are rapidly expanding. Consumer acceptance of this high value crop requires that fruit arrive in excellent condition. Pericarp browning and fungal diseases are the main postharvest problems for longans. Research was conducted to establish optimum storage temperatures and packaging systems to retain fruit quality of ‘Biew Kiew’ longans. Average respiration rates for longans stored at 20 °C (61.6 mg CO2/kg/h) were about twice the rate as those stored at 10 °C (32.7 mg CO2/kg/h) and triple the rate for those stored at 5 °C (21.1 mg CO2/kg/h). Ethylene rates were below 0.4 μg·kg−1·h−1. Fruit quality and shelf life were greatest when stored at 10 °C. Longans held at 20 °C were unmarketable after 10 d, and fruit stored at 5 °C exhibited chilling injury (CI). After storage at 10 °C, longans packaged in microperforated (MP) bags, clamshell (CL) containers, or Peakfresh® film (PF) had the highest visual quality ratings, lowest disease incidences, and longest shelf life when compared with fruit in Lifespan® film (LS) or fiberboard boxes. The most promising packages (MP, CL, PF) were evaluated further under constant 10 °C or simulated shipping (SS) conditions with fluctuating temperatures (22 °C/10 °C/22 °C). Longans in CL containers had the highest visual quality and lowest disease incidence when stored at 10 °C, but there were no differences among package treatments under SS conditions. Also, sensory ratings were greatest for fruit packed in CL or PF when stored at 10 °C but all sensory scores decreased under SS temperatures. When longans were stored under fluctuating temperatures, aril texture and flavor ratings were highest for CL packages. CL, PF, and MP are suitable packages for longans stored under optimal temperatures. However, for longans stored under SS conditions, sensory quality was highest when packaged in CL containers.

Nursing observation of different therapeutic schedules on seawater drowning-induced acute pulmonary edema patients

Objective To clarify the different treatments nursing on seawater drowning-induced acute pulmonary edema patients,and improve the survival rate.Methods According to the treatment,we have federated and traditional groups.99 pulmonary edema patients with seawater drowning in the federated group are treated by scopolamine combined with naloxone,while 70 patients in the traditional group are treated by sildenafil and nikethamide,then the two groups are compared and observed the result through heart rate,average blood pressure,respiration rate,oxygen saturation and the success rate of rescue.Results The two therapeutic schedules make the average blood pressure,respiration rate and oxygen saturation be better(P<0.05).The success rate of rescue in the federated group is 93.93%,and it is 80.00%in another group.So the result of federated group is better than the traditional group(P<0.05).Conclusions Pulmonary edema patients' condition with seawater drowning is dangerous,changes rapidly,and the clinical manifestations is diverse,nursing index,so We need a full-time nurse to give responsible care and real-time monitoring on them,nurses should combine with the combined treatment to improve the success rate of rescue. Key words: Seawater drowning; Pulmonary edema; Treatment; Nursing; Success rate

Aerobic respiration and hypoxia in the Lower St. Lawrence Estuary: Stable isotope ratios of dissolved oxygen constrain oxygen sink partitioning

We measured the concentration and the stable isotope ratios of dissolved oxygen in the water column in the Estuary and Gulf of St. Lawrence to determine the relative importance of pelagic and benthic dissolved oxygen respiration to the development of hypoxic deep waters. The progressive landward decrease of dissolved oxygen in the bottom waters along the axis of the Laurentian Channel (LC) is accompanied by an increase in the 18O:16O ratio, as would be expected from O‐isotope fractionation associated with bacterial oxygen respiration. The apparent O‐isotope effect, εO‐app, of 10.8% reveals that community O‐isotope fractionation is significantly smaller than if bacterial respiration occurred solely in the water column. Our observation can best be explained by a contribution of benthic O2 consumption occurring with a strongly reduced O‐isotope effect at the scale of sediment‐water exchange (εO‐sed ~ 7%). The value for εO‐sed was estimated from benthic O2 exchange simulations using a one‐dimensional diffusion‐reaction O‐isotope model. Adopting this εO‐sed value, and given the observed community O‐isotope fractionation, we calculate that approximately two thirds of the ecosystem respiration occurs within the sediment, in reasonable agreement with direct respiration measurements. Based on the difference between dissolved oxygen concentrations in the deep waters of the Lower St. Lawrence Estuary and in the water that enters the LC at Cabot Strait, we estimate an average respiration rate of 5500 mmol O2 m−2 yr−1 for the 100‐m‐thick layer of bottom water along the LC, 3540 mmol O2 m−2 yr−1 of which is attributed to bacterial benthic respiration.

Root and Microbial Contributions to Soil Respiration during a Soybean Growing Season

Soil respiration is an important process for carbon geochemical cycling. Based on our five long‐term fertilizer experiments, soil respiration was measured using pot experiments with or without planting soybean. Soil respiration rates and soybean root biomass were determined at different observation times. Soil respiration rates due to soil microbial activity could be estimated by extrapolating a newly derived regressive equation at zero root biomass. Soil microbial respiration rates in the control were also observed directly, ranging from 16.0 to 42.7 mg carbon (C) m−2 h−1. Average soil microbial respiration rates from the regression analyses and direct observations were 32.9 and 27.8 mg C m−2 h−1, respectively. The average proportions of soil respiration rates due to the soybean growth were 63.0% using the regressive equation and 69.8% from direct observation. Therefore, the application of these two methods could provide new insight for separating plant root respiration from soil microbial respiration, which is important for estimating their individual contributions to atmospheric carbon dioxide.

Ectomycorrhizal fungi from Alaska and Pennsylvania: adaptation of mycelial respiratory response to temperature?

Ectomycorrhizal fungi from Alaska and Pennsylvania: adaptation of mycelial respiratory response to temperature?

CAMBIOS POSTCOSECHA DEL HONGO COMESTIBLE HUITLACOCHE (Ustilago maydis (D.C.) Corda)

Huitlacoche (Ustilago maydis ( D.C.) Corda) has been an important food in the diet of the inhabitants of the Central-Southern region of Mexico since pre-Columbian times. Recently, its acceptance has increased all around the world. Although it is a highly perishable mushroom, there are no postharvest studies. For these reasons the objective of this work was to identify changes in physical and physiological postharvest parameters of huitlacoche on the corn ear and of cut huitlacoche galls stored at room temperature, 10 °C, and 3 °C for 11 d. The measured variables were changes in appearance, color, weight loss, respiration, production of ethylene and amino acids. The average respiration rate of huitlacoche on the ear at room temperature, 10 and 3 °C was 320.8, 120.8 and 71.5 mLCO2·kg -1 ·h -1 , respectively, and 372.8, 346.7 and 164.1 mLCO2·kg -1 ·h -1 in cut galls, respectively. Weight loss was above 80, 60 and 22 % at room temperature, 10 and 3 °C at 7 days, respectively. Huitlacoche contains 18 amino acids, of these, essential amino acids accounted for 37.8 % of the total. Lysine was 27.2 % of the essential amino acids. After the storage period, there was no major change in amino acid content. The huitlacoche kept its appearance, color and weight better when it was stored at 3 oC on the ear. Ethylene production by huitlacoche was not detected.