首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
Physiological properties of the temperate hermatypic coral Acropora pruinosa Brook with symbiotic algae (zooxanthellae) on the southern coast of the Izu Peninsula, Shizuoka Prefecture, central Japan, were compared between summer and winter. Photosynthesis and respiration rates of the coral with symbiotic zooxanthellae were measured in summer and winter under controlled temperatures and irradiances with a differential gasvolumeter (Productmeter). Net photosynthetic rate under all irradiances was higher in winter than in summer at the lower range of temperature (12–20°C), while lower than in summer at the higher range of temperature (20–30°C). The optimum temperature for net photosynthesis was apt to fall with the decrease of irradiance both in summer and winter, whereas it was higher in summer than in winter under each irradiance. At 25/ 50/100 μmol photons nr2 s?1, it was nearly the sea‐water temperature in each season. Dark respiration rate was higher in winter than in summer, especially in the range from 20–30°C. In both seasons the optimum temperature for gross photosynthesis was 28°C under 400 μmol photons nr2 s?1 and lowered with decreasing irradiance up to 22°C under 25 μmol photons nr2 s?1 in summer, while 20°C under the same irradiance in winter. The optimum temperature for production/respiration (P/R) ratio was higher in summer than in winter under each irradiance. Results indicated that metabolism of coral and zooxanthellae is adapted to ambient temperature condition under nearly natural irradiance in each season.  相似文献   

2.
Ali M  Bhatia A  Kazmi AA  Ahmed N 《Biodegradation》2012,23(2):231-242
Fourier transform-infrared (FT-IR), Thermogravimetry (TG), Differential thermal analyses (DTA) and Differential Thermogravimetric (DTG) studies of a mixture of vegetable waste, saw dust, tree leaves and cow dung for microbial activity (feedstock) and their compost were reported in three different seasons i.e. winter, spring and summer. The correlation between spectral studies and compost composition provide information regarding their stability and maturity during composting. FT-IR spectra were conferred the functional groups and their intensity and TG, DTG and DTA for wt. loss, rate of wt. loss and enthalpy change in compost. Weight loss in feedstock and compost at two different temperatures 250–350 and 350–500°C was found 38.06, 28.15% for inlet and 14.08, 25.67% for outlet zones in summer and 50.59, 29.76% for inlet and 18.08, 25.67% in outlet zones in spring season, higher (5–10%) than winter. The corresponding temperatures in DTA in the samples from inlet to outlet zone were; endotherm (100–200°C), due to dehydration, exotherm (300–320°C), due to peptidic structure loss and exotherm (449–474°C) due to the loss of polynuclear aromatic structures, which were higher by 4°C and 10–20°C and rate of wt. loss was higher by 5–10% in spring and summer season, respectively than winter season composting, reported regardless of the maturation age of the compost. Relative intensity of exotherms (300–320/449–474°C) gave the thermally more stable fractions of organic compound. Our results indicated that the rotary drum composting of organic matters in spring and summer season gave higher molecular complexity and stability than the winter season.  相似文献   

3.
Four growth trials (each of 11 weeks duration) were conducted during different seasons throughout 1 year, namely, winter, summer, monsoon and post‐monsoon to assess the seasonal influence on growth and production of koi carp, Cyprinus carpio var. koi L. larvae in concrete tanks maintained under different management regimes. Individual weight gain, survival rate, fish deformities and number of marketable fish in each season were compared among four management regimes: (i) carp larvae fed with live zooplankton (LF); (ii) direct fertilization with poultry manure (PM); (iii) direct fertilization with cow dung (CD); and (iv) a control system (C), where a commercial diet containing 32% crude protein was applied. There were three replicates for each treatment. The LF treatment produced significantly higher weight gain, survival rate and number of marketable fish in all seasons (P < 0.05), compared with the other treatments, through maintenance of better water quality and greater abundance of zooplankton in the system. Fish deformities were highest in the C treatment in every season (P < 0.05). Water temperatures averaged 18.6°C (winter), 29.7°C (summer), 28.3°C (monsoon), and 26.5°C in the post‐monsoon trial. Average weight gain of koi carp achieved during the winter trial (2.01 g in C to 4.44 g in LF) was considerably lower than that achieved in the summer, monsoon or post‐monsoon trials. Survival rates of carp ranged from 70.5% (C) to 95.5% (LF) in the winter trial, and were considerably lower than the other seasons. The number of marketable fish was also lowest during the winter trial.  相似文献   

4.
Obese subjects may be more vulnerable to injury from heat stress, and appear to be less efficient at thermoregulation. Sweat rate, tympanic temperature and osmolality in obese subjects were investigated in Japan during two seasons. The purpose of this study was to examine the relationship between obesity, thermoregulatory response and season. Five obese (BMI, 32.0?±?4.9 kg/m2) and five non-obese (BMI, 23.2?±?2.9 kg/m2) men participated in this experiment at latitude 35°10′ N and longitude 136°57.9′E. The average atmospheric temperature was 29.1?±?1.0 °C in summer and 3.3?±?1.4 °C in winter. Tympanic temperature and sweat rate were measured during leg water immersion at 42 °C for 30 min. Blood samples were analyzed for plasma osmolality. The relationship between tympanic temperature and sweat rate decreased significantly in obese compared to in non-obese subjects in both seasons, there being a lowered sweat rate for any core temperature in obese subjects. Plasma osmolality was significantly higher in obese than in non-obese subjects in both seasons. Thermal sensation increased significantly in non-obese than in obese in winter but not in summer. Our data show that thermoregulatory responses are attenuated in obese subjects compared with controls, suggesting that obese people are at increased risk of heat-related illnesses.  相似文献   

5.
The stress response of Oncorhynchus mykiss in high‐altitude farms in central Mexico was investigated over two seasons: the cool (9·1–13·7° C) dry winter season, and the warmer (14·7–15·9° C), wetter summer season. Fish were subjected to an acute stress test followed by sampling of six physiological variables: blood cortisol, glucose, lactate, total antioxidant capacity, haemoglobin concentration and per cent packed cell volume (VPC%). Multivariate analyses revealed that lactate and total antioxidant capacity were significantly higher in the summer, when water temperatures were warmer and moderate hypoxia (4·9–5·3 mg l?1) prevailed. In contrast, plasma cortisol was significantly higher in the winter (mean ± s.e .: 76·7 ± 4·0 ng ml?1) when temperatures were cooler and dissolved oxygen levels higher (6·05–7·9 mg l?1), than in the summer (22·7 ± 3·8 ng ml?1). Haemoglobin concentrations (mg dl?1) were not significantly different between seasons, but VPC% was significantly higher in the summer (50%) than in the winter (35%). These results suggest that in summer, effects of high altitude on farmed fish are exacerbated by stresses of high temperatures and hypoxia, resulting in higher blood lactate, increased total antioxidant capacity and elevated VPC% levels.  相似文献   

6.
Deka H  Deka S  Baruah CK  Das J  Hoque S  Sarma H  Sarma NS 《Bioresource technology》2011,102(24):11212-11217
Laboratory investigation on vermicomposting efficacy of Perionyx excavatus for recycling of distillation waste biomass of java citronella (Cymbopogon winterianus Jowitt) was carried out in two seasonal trials i.e. summer and winter periods. The experiment was conducted in earthen pots using a mixture of citronella waste material and cowdung in the proportion of 5:1. A control treatment without earthworms was setup for comparison of the results. The vermicompost had shown 5.8 folds reduction in C/N ratio and 5.6 folds enhancement in ash content. The nutrient contents (N, P, K, Ca and Mg) in the vermicompost had increase in the range of 1.2 - 4.1 fold than the initial level. The FT-IR spectra of the vermicompost confirmed increase in nitrogen rich compounds and decrease in aliphatic/aromatic compounds as compared to the initial level of the biowaste materials. The vermicomposting process is influenced by seasonal variation and summer was more productive than winter.  相似文献   

7.
Abstract

The resting metabolic rate (RMR) of Hemidactylus flaviviridis was measured at different temperatures from 20 to 35°C during winter and summer acclimatization. The mass exponent b values ranged between 0.67 and 0.72. Winter-acclimatized geckos of various body masses had significantly lower RMRs than summer-acclimatized geckos only at 20°C. It seems that low thermal sensitivity for summer–acclimatized group may facilitate activity during its active seasons, and high thermal sensitivity between 20 and 25°C for winter–acclimatized group may conserve energy during inactivity in winter.  相似文献   

8.
Recycling of organic wastes by employing Eisenia fetida   总被引:4,自引:0,他引:4  
Yadav A  Garg VK 《Bioresource technology》2011,102(3):2874-2880
This paper reports the recycling of nutrients by vermicomposting of cow dung (CD), poultry droppings (PD) and food industry sludge (FIS) employing earthworms (Eisenia fetida). A total of six vermicomposting units were established and dynamics of chemical and biological parameters has been studied for 13 weeks. The waste mixture containing 50% CD+25% PD+25% FIS had better fertilizer value among studied waste combinations. At the end of experiment, vermicomposts showed decrease in pH and organic C, but increase in EC, total Kjeldhal N, total available P and total K contents. The C:N ratio of final vermicomposts also reduced to 10.7-12.7 from 22.8 to 56 in different waste combinations. The earthworms have good biomass gain and cocoon production in all vermicomposting units but CD alone and 50% CD+25% PD+25% FIS were better than other studied combinations.  相似文献   

9.
We investigated seasonal changes in hormonal and thermoregulatory responses. Eight volunteers were subjected to the experiment at four times of the year: around the vernal and autumnal equinoxes, and at the summer and winter solstices at latitude 35° N. Plasma antidiuretic hormone (ADH), angiotensin II (ANG II), aldosterone (ALD) and plasma renin activity (PRA) were analyzed before and after water immersion. Seasonal changes in thermoregulatory responses were assessed by measuring core temperature and sweat rate during immersion of the leg in hot water (at 42°C) for 30 min in a room maintained at 26°C. The concentration of plasma ADH and ALD before water immersion was significantly higher in summer than in other seasons. The concentrations of ANG II and PRA did not show seasonal variations. Changes in tympanic temperature during water immersion showed significant differences between seasons, and were higher in winter than in other seasons. The sweat rate was significantly higher in summer than in other seasons. In summary, ADH and ALD concentrations displayed a seasonal rhythm with marked elevation in summer; this may be a compensative mechanism to prevent dehydration from increased sweat loss during summer due to heat acclimatization.  相似文献   

10.
The gecko Oedura marmorata was studied in two different climatic zones: the arid zone of central Australia and in the wet-dry tropics of northern Australia. Doubly labelled water was used to measure field metabolic rate (FMR) and water flux rates of animals in the field during the temperate seasons of spring, summer and winter, and during the tropical wet and dry seasons. FMRs were highest in the tropical wet season and lowest in the temperate winter. The geckos in central Australia expended less energy than predicted for a similarly sized iguanid lizard, but geckos from the tropics expended about the same amount of energy as predicted for an iguanid. Water flux rates of geckos from the arid zone were extremely low in all seasons compared to other reptiles, and although water flux was higher in tropical geckos, the rates were low compared to other tropical reptiles. The standard metabolic rates (SMRs) of geckos were similar between the two regions and among the seasons. Geckos selected higher body temperatures (T bs) in a laboratory thermal gradient in the summer (33.5°C) and wet (33.8°C) seasons compared to the winter (31.7°C) and dry (31.4°C) seasons. The mean T bs selected in the laboratory thermal gradient by geckos from the two regions were not different at a given time of year. The energy expended during each season was partitioned into components of resting metabolism, T b and activity. Most of the energy expended by geckos from central Australia could be attributed to the effects of temperature on resting lizards in all three seasons, but the energy expended by tropical geckos includes a substantial component due to activity during both seasons. This study revealed variability in patterns of ecological energetics between populations of closely related geckos, differences which cannot be entirely attributed to seasonal or temperature effects. Received: 14 November 1997 / Accepted: 4 May 1998  相似文献   

11.
This study investigated whether composting methods differ in their impact on seed germination of Rumex obtusifolius (broad‐leaved dock). Weed seeds were buried in windrows of cattle farmyard manure, removed at monthly intervals and germinated during the course of 7 months. Composting methods differed in the maximum temperatures reached (63°C for conventional and biodynamic composting and 35°C for vermicomposting), the addition of 1000 m?2 earthworms (Eisenia fetida) for vermicomposting and the inoculation of biodynamic preparations for biodynamic composting. After 1 month in windrows, germination rate of Rumex seeds was significantly higher in vermicompost (48%) than in conventional (28%) or biodynamic compost (18%). After 2 months in windrows, 26% of the seeds germinated in vermicomposting windrows, while those inserted in conventional and biodynamic windrows showed a negligible germination (0% and 2%, respectively). After 3 and 4 months, only seeds under vermicomposting germinated (22% and 3%, respectively). No germination was determined when seeds were inserted for longer than 4 months in any of the treatments. Seeds stored at room temperature germinated at 89% over the course of the experiment. Results suggest that the maximum temperature reached in windrows is not the single main factor reducing weed seed germination during composting.  相似文献   

12.
A study (100 days duration) was conducted to evaluate the efficiency of an exotic earthworm species (epigeic-Eisenia foetida) for decomposition of different types of organic substrates (kitchen waste, agro-residues, institutional and industrial wastes including textile industry sludge and fibres) into valuable vermicompost. The percentage of, nitrogen, phosphorous and potassium in vermicompost was found to increase while pH and total organic carbon declined as a function of the vermicomposting period. 4.4-5.8-fold increases in TKN was observed in different feed mixtures at the end of vermicomposting period. The increase in TKN for different feed substrates was found in the order: textile sludge>textile fibre=institutional waste>agro-residues>kitchen waste. Available Phosphorus increased 1.4 to 6.5-fold in different feed mixtures in comparison to control. Reduction in TOC was highest in agro-residues (3-fold) followed by kitchen waste (2.2-fold), institutional waste (1.7-fold) and textile industrial wastes (sludge, 1.5-fold and fibre, 1.68-fold) in earthworm-inoculated pots than control. The data reveals that vermicomposting (using E. foetida) is a suitable technology for the decomposition of different types of organic wastes (domestic as well as industrial) into value-added material.  相似文献   

13.
The effect of 21 days of starvation, followed by a period of compensatory growth during refeeding, was studied in juvenile roach Rutilus rutilus during winter and summer, at 4, 20 and 27° C acclimation temperature and at a constant photoperiod (12L : 12D). Although light conditions were the same during summer and winter experiments and fish were acclimated to the same temperatures, there were significant differences in a range of variables between summer and winter. Generally winter fish were better prepared to face starvation than summer fish, especially when acclimated at a realistic cold season water temperature of 4° C. In winter, the cold acclimated fish had a two to three‐fold larger relative liver size with an approximately double fractional lipid content, in comparison to summer animals at the same temperature. Their white muscle protein and glycogen concentration, but not their lipid content, were significantly higher. Season, independent of photoperiod or reproductive cycle, was therefore an important factor that determined the physiological status of the animal, and should generally be taken into account when fish are acclimated to different temperature regimes. There were no significant differences between seasons with respect to growth. Juvenile roach showed compensatory growth at all three acclimation temperatures with maximal rates of compensatory growth at 27° C. The replenishment of body energy stores, which were utilized during the starvation period, was responsible for the observed mass gain at 4° C. The contribution of the different energy resources (protein, glycogen and lipid) was dependent on acclimation temperature. In 20 and 27° C acclimated roach, the energetic needs during food deprivation were met by metabolizing white muscle energy stores. While the concentration of white muscle glycogen had decreased after the fasting period, the concentrations of white muscle lipid and protein remained more or less constant. The mobilization of protein and fat was revealed by the reduced size of the muscle after fasting, which was reflected in a decrease in condition factor. At 20° C, liver lipids and glycogen were mobilized, which caused a decrease both in the relative liver size and in the concentration of these substrates. Liver size was also decreased after fasting in the 4° C acclimated fish, but the substrate concentrations remained stable. This experimental group additionally utilized white muscle glycogen during food deprivation. Almost all measured variables were back at the control level within 7 days of refeeding.  相似文献   

14.
Pepper seed quality is sensitive to variations in climatic conditions during seed development, which might be associated with accumulation, distribution and leakage of mineral elements from the seeds. This was examined in hybrid seeds of sweet pepper (Capsicum annuum L. cv.‘Hazera’ 1195) in two experiments during two growing seasons. The mean daily temperature (day/night) and daily total radiation receipt during seed development were 27.9/23.2°C and 8.63 kW m?2 in the summer and 18.3/ 14.9°C and 3.18 kW m?2 in the winter, respectively. Seeds developed in the summer had lower percentage of seedling emergence and leaked a larger portion (45%) of their K content into the water medium than in winter‐developed seeds. Summer seeds accumulated more K and Cl, but less P, Mg, Ca and the weight ratio of linoleic acid to oleic acid was lower than in the winter seeds. The season did not significantly affect N, S and total fatty acids. The most abundant element on the seed coat surface was K in the summer and Ca in the winter seeds. The cotyledon and endosperm of the summer seeds contained relatively higher ratios of K and Ca and lower ratios of P and Mg than the winter seeds. Transportation of mineral nutrients appeared to be involved in the effect of heat and moisture stresses on emergence quality of the pepper seeds.  相似文献   

15.
《Chronobiology international》2012,29(12):1646-1657
ABSTRACT

We performed large-scale analyses of circadian and infradian cycles of human body temperature, focusing on changes over the day, week, and year. Temperatures (n= 93,225) were collected using temporal artery thermometers from a Boston emergency department during 2009–2012 and were statistically analyzed using regression with cyclic splines. The overall mean body temperature was 36.7°C (98.1°F), with a 95% confidence interval of 36.7–36.7°C (98.1–98.1°F) and a standard deviation of 0.6°C (1.1°F). Over the day, mean body temperature followed a steady cycle, reaching its minimum at 6:00–8:00 and its maximum at 18:00–20:00. Across days of the week, this diurnal cycle was essentially unchanged, even though activities and sleeping hours change substantially during the weekly cycles of human behavior. Over the year, body temperatures were slightly colder in winter than summer (~0.2°C difference), consistent with most prior studies. We propose these seasonal differences might be due to ambient effects on body temperature that are not eliminated because they fall within the tolerance range of the thermoregulatory system. Over the year, bathyphase (daily time of minimum temperature) appeared to parallel sunrise times, as expected from sunrise’s zeitgeber role in circadian rhythms. However, orthophase (daily time of maximum temperature) and sunset times followed opposite seasonal patterns, with orthophase preceding nightfall in summer and following nightfall in winter. Throughout the year, bathyphase and orthophase remained separated by approximately 12 h, suggesting this interval might be conserved. Finally, although 37.0°C (98.6°F) is widely recognized as the mean or normal human body temperature, analysis showed mean temperature was <37.0°C during all times of day, days of the week, and seasons of the year, supporting prior arguments that the 37.0°C standard has no scientific basis. Overall, this large study showed robust and consistent behavior of the human circadian cycle at the population level, providing a strong example of circadian homeostasis.  相似文献   

16.
Zooxanthellae mitotic index (MI) and expulsion rates were measured in the facultatively symbiotic scleractinian Astrangia poculata during winter and summer off the southern New England coast, USA. While MI was significantly higher in summer than in winter, mean expulsion rates were comparable between seasons. Corals therefore appear to allow increases in symbiont density when symbiosis is advantageous during the warm season, followed by a net reduction during the cold season when zooxanthellae may draw resources from the coral. Given previous reports that photosynthesis in A. poculata symbionts does not occur below approximately 6°C, considerable zooxanthellae division at 3°C and in darkness suggests that zooxanthellae are heterotrophic at low seasonal temperatures. Finally, examination of expulsion as a function of zooxanthellae density revealed that corals with very low zooxanthellae densities export a significantly greater proportion of their symbionts, apparently allowing them to persist in a stable azooxanthellate state.  相似文献   

17.
The paper deals with the variations in the toxicity of 2,4-D to Cyprinus carpio at different temperatures during different seasons of the year. The higher temperature has higher toxicity and vice versa at the same concentration. The TLm values indicate that there is a 7–7.5 fold increase in toxicity with the rise in temperature from 17°C in February (winter) to 39°C in May (summer). These results have significance in manipulating the 2,4-D doses for the eradication of aquatic weeds in different seasons.  相似文献   

18.
We assessed the seasonal variations in the effects of hypercarbia (3 or 5% inspired CO2) on cardiorespiratory responses in the bullfrog Rana catesbeiana at different temperatures (10, 20 and 30 degrees C). We measured breathing frequency, blood gases, acid-base status, hematocrit, heart rate, blood pressure and oxygen consumption. At 20 and 30 degrees C, the rate of oxygen consumption had a tendency to be lowest during winter and highest during summer. Hypercarbia-induced changes in breathing frequency were proportional to body temperature during summer and spring, but not during winter (20 and 30 degrees C). Moreover, during winter, the effects of CO2 on breathing frequency at 30 degrees C were smaller than during summer and spring. These facts indicate a decreased ventilatory sensitivity during winter. PaO2 and pHa showed no significant change during the year, but PaCO2 was almost twice as high during winter than in summer and spring, indicating increased plasma bicarbonate levels. The hematocrit values showed no significant changes induced by temperature, hypercarbia or season, indicating that the oxygen carrying capacity of blood is kept constant throughout the year. Decreased body temperature was accompanied by a reduction in heart rate during all four seasons, and a reduction in blood pressure during summer and spring. Blood pressure was higher during winter than during any other seasons whereas no seasonal change was observed in heart rate. This may indicate that peripheral resistance and/or stroke volume may be elevated during this season. Taken together, these results suggest that the decreased ventilatory sensitivity to hypercarbia during winter occurs while cardiovascular parameters are kept constant.  相似文献   

19.
Seasonal variations in the ex vivo phagocytic function of blood cells from tench, including ingestion capacity of inert particles and its destruction (microbicide capacity) assessed by measurement of superoxide anion production, were studied. Tench were maintained under natural conditions throughout the year, and the different assays of samples taken during each season were initially performed in vitro at 22°C and the results compared. Subsequently, assays were performed at the same temperature as that of the water ponds in which the fish were kept (“seasonal temperature”: 12°C in winter, 22°C in spring and autumn and 30°C in summer) and the results compared seasonally. The results at 22°C showed that phagocytic capacity was greatest in spring and summer and lowest in winter. However, when phagocytic capacity was measured at seasonal temperature, highest values appeared in winter and lowest in summer and autumn. Nitroblue tetrazolium reduction by tench phagocytes after phagocytosing latex beads demonstrated a similar seasonal behaviour at both 22°C in each season and at seasonal temperature. The highest values appeared in summer, which suggests a better microbicide capacity in this season. The results obtained in this study suggest that for a correct interpretation of ex vivo phagocytic capacity of fish through the year it is necessary to use the same assay temperature as that of the water in which the fish is kept.  相似文献   

20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号