Pronounced Diurnal Changes Research Articles

Effect of thermal environmental factors on female students during summer and spring season: promoting a sustainable campus initiative

PurposeThe present study was conducted at the female campus of the United Arab Emirates University (UAEU), with a specific emphasis on the outside environment. This study aims to explore the influence of external conditions, including AC (AC), Time of Day (TD) variations, and Landscape Sites (LS) differences, on changes in physiological temperatures. Specifically, the focus is on understanding the dynamics of skin and abaya temperature (AT) when exposed to transient thermal environments, considering factors such as AC, LS, and different TD. By investigating these parameters, the research aims to gain insights into the thermal dynamics experienced by female students at the UAEU campus which can further lead to evaluate the thermal comfort (TC).Design/methodology/approachThe study involved three college-aged female participants simulating a daily walk to class on a arid tropical university campus. Real-time thermal measures were captured at 10-min intervals using the FLIR Thermal Camera. Statistical analyses, including the Kruskal–Wallis test and Don Bonferroni pairwise comparisons, were employed to assess significant differences in thermal conditions based on AC, TD, and LS. These tests rigorously analyzed the data to identify statistically significant variations in thermal conditions among the specified factors. Additionally, temperature data from the ECMWF ERA5 dataset, covering global climate from January 1940 to the present, was utilized. The GRADS application on a Linux-based system was used for data visualization and map chart creation.FindingsThe study reveals a slight influence of AC on both Abaya temperatures (AT) and Skin temperatures (ST) during the summer, with more pronounced diurnal changes in the afternoon significantly affecting both metrics. Site characteristics minimally impact AT, but they have a noteworthy effect on ST. In the spring season, AT and ST remain unaffected by AC, while temporal fluctuations, particularly in the afternoon, exert a significant influence. LS variations show statistically insignificant impacts on both AT and ST. Additionally, temperature maps for specific 2023 dates provide distinctive trends in the UAE, offering insights into dynamic climatic conditions varying by season and TD.Originality/valueThe study aims to address a knowledge gap by investigating the influence of AC, TD, and LS variations on physiological temperature change, specifically focusing on skin and AT. This investigation is conducted in the context of individuals exposed to thermal environmental factors within a arid tropical university campus setting.Practical implicationsThis research contributes to the existing knowledge by providing specific data on thermal conditions within the campus, enabling informed decision-making for creating a more comfortable and conducive environment for the students, thereby contributing to the goal of a sustainable campus.

Carbon acquisition by Trichodesmium: the effect of pCO2 and diurnal changes

We investigated carbon acquisition by the N2‐fixing cyanobacterium Trichodesmium IMS101 in response to CO2 levels of 15.1, 37.5, and 101.3 Pa (equivalent to 150, 370, and 1000 ppm). In these acclimations, growth rates as well as cellular C and N contents were measured. In vivo activities of carbonic anhydrase (CA), photosynthetic O2 evolution, and CO2 and HCO3‐ fluxes were measured using membrane inlet mass spectrometry and the 14C disequilibrium technique. While no differences in growth rates were observed, elevated CO2 levels caused higher C and N quotas and stimulated photosynthesis and N2 fixation. Minimal extracellular CA (eCA) activity was observed, indicating a minor role in carbon acquisition. Rates of CO2 uptake were small relative to total inorganic carbon (Ci) fixation, whereas HCO{3 contributed more than 90% and varied only slightly over the light period and between CO2 treatments. The low eCA activity and preference for HCO3‐ were verified by the 14C disequilibrium technique. Regarding apparent affinities, half‐saturation concentrations (K1/2) for photosynthetic O2 evolution and HCO3‐ uptake changed markedly over the day and with CO2 concentration. Leakage (CO2 efflux : Ci uptake) showed pronounced diurnal changes. Our findings do not support a direct CO2 effect on the carboxylation efficiency of ribulose‐1,5‐bisphosphate carboxylase/oxygenase (RubisCO) but point to a shift in resource allocation among photosynthesis, carbon acquisition, and N2 fixation under elevated CO2 levels. The observed increase in photosynthesis and N2 fixation could have potential biogeochemical implications, as it may stimulate productivity in N‐limited oligotrophic regions and thus provide a negative feedback in rising atmospheric CO2 levels.

Transcriptional profiles of organellar metabolite transporters during induction of crassulacean acid metabolism in Mesembryanthemum crystallinum.

Metabolite transport across multiple organellar compartments is essential for the operation of crassulacean acid metabolism (CAM). To investigate potential circadian regulation of inter-organellar metabolite transport processes, we have identified eight full-length cDNAs encoding an organellar triose phosphate / Pi translocator (McTPT1), a phosphoenolpyruvate / Pi translocator (McPPT1), two glucose-6-phosphate / Pi translocators (McGPT1, 2), two plastidic Pi translocator-like proteins (McPTL1, 2), two adenylate transporters (McANT1, 2), a dicarboxylate transporter (McDCT2), and a partial cDNA encoding a second dicarboxylate transporter (McDCT1) in the model CAM plant, Mesembryanthemum crystallinum L. We next investigated day / night changes in steady-state transcript abundance of each of these transporters in plants performing either C3 photosynthesis or CAM induced by salinity or water-deficit stress. We observed that the expression of both isogenes of the glucose-6-phosphate / Pi translocator (McGPT1, 2) was enhanced by CAM induction, with McGPT2 transcripts exhibiting much more pronounced diurnal changes in transcript abundance than McGPT1. Transcripts for McTPT1, McPPT1, and McDCT1 also exhibited more pronounced diurnal changes in abundance in the CAM mode relative to the C3 mode. McGPT2 and McDCT1 transcripts exhibited sustained oscillations for at least 3 d under constant light and temperature conditions suggesting their expression is under circadian clock control. McTPT1 and McGPT2 transcripts were preferentially expressed in leaf tissues in either C3 or CAM modes. The leaf-specific and / or circadian controlled gene expression patterns are consistent with McTPT1, McGPT2 and McDCT1 playing CAM-specific metabolite transport roles.

Dynamics of refuge use: diurnal, vertical migration by predatory and herbivorous mites within cassava plants

Plants may protect themselves against herbivorous arthropods by providing refuges to predatory arthropods, but they cannot prevent herbivores from taking countermeasures or even from reaping the benefits. To understand whether plants benefit from providing self‐made refuges (so‐called domatia), it is not only necessary to determine the fitness consequences for the plant, but also to assess (1) against which factors the refuge provides protection, (2) why predatory arthropods are more likely to monopolise the refuge, and (3) how herbivorous and predatory arthropods respond to and affect each other in and outside the refuge. In this article, we focus on the last aspect by studying the dynamics of refuge use of a predatory mite (Typhlodromalus aripo) and its consequences for a herbivorous mite (Mononychellus tanajoa) on cassava plants in Benin, West Africa. The refuge, located in‐between the leaf primordia of the cassava apex, is thought to provide protection against abiotic factors and/or intraguild predators. To test whether the predator waits for prey in the apex or comes out, we sampled predator‐prey distributions on leaves and in the apex at 4 hour‐intervals over a period of 24 hours. The predatory mites showed pronounced diurnal changes in within‐plant distribution. They were in the apices during the day, moved to the young leaves during night and returned to the apices the next morning. Nocturnal foraging bouts were more frequent when there were more herbivorous mites on the leaves near the apex. However, the foraging predators elicited an avoidance response by mobile stages of their prey, since these were more abundant on the first 20 leaves below the apex during late afternoon, than on the same leaves during night. These field observations on cassava plants show that (1) during daytime predatory mites monopolise the apical domatia, (2) they forage on young leaves during night and (3) elicit avoidance by within‐plant, vertical migration of mobile stages of the herbivorous mites. We hypothesize that cassava plants benefit from apical domatia by acquiring protection for their photosynthetically most active, young parts, because predatory mites (1) protect primordial leaves in the apex, (2) reduce the densities of herbivorous mites on young leaves, and (3) cause herbivorous mites to move down to less profitable older leaves.

A Climatology of Surface Baroclinic Zones

Analyses of surface potential temperature for one year over the contiguous United States, southern Canada, northern Mexico, and adjacent oceanic areas showed three regions of relatively high frequency of strong gradients. These were the Atlantic and Gulf coasts, the Pacific coast, and the eastern slopes of the North American Cordillera. The Atlantic and Gulf zone was most pronounced at 1200 UTC during winter. The Pacific coast zone was most frequent at 0000 UTC in summer. The zone on the eastern slopes was present at both times and during all seasons but was most pronounced at 1200 UTC in winter. The locations of the maxima and the pronounced diurnal changes provide circumstantial evidence that the horizontal variation of diabatic heating and cooling due to surface heat flux is a more important physical mechanism than confluence is in the creation of surface baroclinic zones. An example is shown of the importance of the East Coast zone for weather forecasting during the cold season. In January of 2000 a low pressure center propagated along the surface baroclinic zone, separating cold air over land from warm air over the water, rather than following the deep baroclinic zone in the troposphere. During the warm season, the ‘‘backdoor cold front,’’ separating cool air over the water from hot air over land, presents a challenging forecast problem. Many analyzed fronts are not associated with significant horizontal density gradients. Because of these and other surface analysis issues, short-range forecasting might benefit from routine analysis of the surface temperature field.

Sea breezes and coastal jets in southeastern Spain

Sea breezes and low-level jet (LLJ) streams are studied in the region between the Eastern Castilla-La Mancha and the Mediterranean coast of southeastern Spain. The simplified concept of two-dimensional terrain and meteorological conditions explains the spatially and diurnally varying wind system consistently. The changes, as a function of time, height and distance to the coast, of temperature, pressure and wind as well as of certain observed phenomena, such as LLJs and strongly baroclinic zones, result from the response of the mesoscale flow to differential heating. Wind changes are generally found to be consistent with mesoscale changes in geostrophic winds as estimated from station pressure measurements. The LLJs mark the penetration depth of the sea breeze during daytime, where a baroclinic zone develops at the transition between continental air masses and marine air masses, typically at a distance of 150 km from the coast. The analysis is based on aerological data and ground-based measurements from the European Field Experiment in a Desertification Threatened Area (EFEDA) experiments in 1991 and 1994 as well as on 3-hourly data from three synoptic stations of the Spanish meteorological network for April–October in 1991 and 1994. After corrections were made for instrument errors and atmospheric tides, diurnal pressure variations document vertically integrated mass fluxes perpendicular to the coast. Amplitudes of diurnal pressure and temperature changes scatter significantly and are largest in midsummer. They are weakly correlated and pressure amplitudes remain large in spring and autumn when diurnal temperature changes are reduced. With about 6 h delay to the regular development of onshore winds at the coast during daytime, pronounced wind peaks are observed over the eastern plateau at Albacete and Barrax in the late afternoon. Case studies show that they are accompanied by development of baroclinically driven LLJs, whereas winds at Tomelloso, 220-km inland, show less pronounced diurnal changes and are beyond the normal penetration distance of sea breezes. Copyright © 2000 Royal Meteorological Society

Sea breezes and coastal jets in southeastern Spain

Sea breezes and low-level jet (LLJ) streams are studied in the region between the Eastern Castilla-La Mancha and the Mediterranean coast of southeastern Spain. The simplified concept of two-dimensional terrain and meteorological conditions explains the spatially and diurnally varying wind system consistently. The changes, as a function of time, height and distance to the coast, of temperature, pressure and wind as well as of certain observed phenomena, such as LLJs and strongly baroclinic zones, result from the response of the mesoscale flow to differential heating. Wind changes are generally found to be consistent with mesoscale changes in geostrophic winds as estimated from station pressure measurements. The LLJs mark the penetration depth of the sea breeze during daytime, where a baroclinic zone develops at the transition between continental air masses and marine air masses, typically at a distance of 150 km from the coast. The analysis is based on aerological data and ground-based measurements from the European Field Experiment in a Desertification Threatened Area (EFEDA) experiments in 1991 and 1994 as well as on 3-hourly data from three synoptic stations of the Spanish meteorological network for April–October in 1991 and 1994. After corrections were made for instrument errors and atmospheric tides, diurnal pressure variations document vertically integrated mass fluxes perpendicular to the coast. Amplitudes of diurnal pressure and temperature changes scatter significantly and are largest in midsummer. They are weakly correlated and pressure amplitudes remain large in spring and autumn when diurnal temperature changes are reduced. With about 6 h delay to the regular development of onshore winds at the coast during daytime, pronounced wind peaks are observed over the eastern plateau at Albacete and Barrax in the late afternoon. Case studies show that they are accompanied by development of baroclinically driven LLJs, whereas winds at Tomelloso, 220-km inland, show less pronounced diurnal changes and are beyond the normal penetration distance of sea breezes. Copyright © 2000 Royal Meteorological Society

Glycosidically bound volatile components of Nicotiana sylvestris and N. Suaveolens flowers

Glycosidically bound volatile components were extracted from flowers of Nicotiana sylvestris and N. suaveolens and isolated using liquid column chromatography with an Amberlite XAD-2 resin. These glycosides, which were putative precursors of fragrance compounds, were hydrolysed enzymatically and a number of the volatiles released were subsequently identified by GC-MS including compounds not previously identified in the floral headspace of these species. Average yields of volatiles released from glycosides were ca 230 and 1050 μg g −1 for N. sylvestris and N. suaveolens flowers, respectively. Compounds in the glycosidically bound fraction were all phenylpropanoid-derived volatiles (e.g. benzyl alcohol, benzaldehyde, E-cinnamyl alcohol, benzyl salicylate) with the exception of the monoterpene α-terpineol. No pronounced diurnal changes in the levels of glycosidically bound volatile compounds could be noted from flowers of either species. However, pronounced differences were obtained in the concentrations of glycosidically bound volatiles at different floral maturity stages.

ACCLIMATION TO SPECTRAL IRRADIANCE IN ALGAE

Journal of PhycologyVolume 27, Issue 1 p. 8-14 ACCLIMATION TO SPECTRAL IRRADIANCE IN ALGAE Paul G. Falkowski, Corresponding Author Paul G. Falkowski Oceanographic and Atmospheric Sciences Division, Brookhaven National Laboratory, Upton, New York 11973Address for reprint requests.Search for more papers by this authorJulie LaRoche, Julie LaRoche Oceanographic and Atmospheric Sciences Division, Brookhaven National Laboratory, Upton, New York 11973Search for more papers by this author Paul G. Falkowski, Corresponding Author Paul G. Falkowski Oceanographic and Atmospheric Sciences Division, Brookhaven National Laboratory, Upton, New York 11973Address for reprint requests.Search for more papers by this authorJulie LaRoche, Julie LaRoche Oceanographic and Atmospheric Sciences Division, Brookhaven National Laboratory, Upton, New York 11973Search for more papers by this author First published: February 1991 https://doi.org/10.1111/j.0022-3646.1991.00008.xCitations: 504 The research of the authors was supported by the U.S. Department of Energy under Contract DE-AC02-76CH00016. Question (Turpin): Does resource limitation (e.g. C, N, or P) constrain the ability of algal cells to undergo photoacclimation? Answer: Yes, resource limitation definitely constrains the photoacclimation response. The availability of N, for example, determines the cellular content of LHCPs. The paper by Chalup and Laws (1990) reveals how N availability modifies responses to irradiation. Question (Davison): Pronounced diurnal changes in irradiance occur in the natural environment, with morning and evening light levels typically being much lower than those at noon. Do algae change their photosynthetic apparatus in response to these changes? Answer: As we briefly discussed, algae do not photoacclimate at night; however, they do change their photosynthetic apparatus. Many algae become entrained in a circadian rhythm, where Chl/cell increases through the day and decreases close to the onset of night. This trait has been retained to some extent in higher plants. This cycle is exactly opposite to what would be expected if algae photoacclimate throughout the day. Rather, it would appear that algae respond to day-to-day variations in irradiance. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume27, Issue1February 1991Pages 8-14 RelatedInformation

Evaluation of factors contributing to diurnal changes in O2 concentrations in floodwater of deepwater rice fields

SUMMARYGlass chambers were used to isolate 0–75 m deep water columns in situ in deepwater rice fields in Thailand to evaluate the contribution by various factors to the pronounced diurnal changes in O2 concentrations in the floodwater Chambers filled with distilled water provided estimates of O2 flow from the air into the water, indicating the importance of eddy currents associated with wind action and evaporative cooling. Darkening the natural water gave estimates for O2 evolution due to photosynthesis, while comparisons between columns with and without rice distinguished between O2 evolution and consumption by the rice and the biomass other than rice respectively. Removal of the above water portions of the rice shoots showed the importance of the emergent portion of the canopy to O2 movement from the air into the aquatic part of the ecosystem. This flow may be associated with O2 flow through the lacunae and via air envelopes around the leaf, and with turbulence caused by swaying of the rice leaves in the wind.The changes in O2 concentration were analysed quantitatively using several simplifying assumptions. One major input was a net O2 flow from the air into the water, about half being due to a net flow across the air–water interface and the other half to flow associated with the rice plants. During the night, these flows were less than the O2 uptake by the biomass, hence O2 concentrations decreased. In the underwater portion of the rice stand, about 60 % of the O2 uptake was due to the rice and about 40% due to the biomass other than rice. During the day, the O2 requirements by respiration were more than compensated for by O2 evolution due to photosynthesis, resulting in increases in O2 concentration of the water.

Influence of fruit load and environmental factors on nitrate reductase activity and on concentration of nitrate and carbohydrates in leaves of eggplant (Solanum melongena)

Both the in vivo (+ nitrate) nitrate reductase (NR) activity (leaf disks incubated in the presence of KNO3) and the in vivo (− nitrate) NR activity (leaf disks incubated without KNO3) in leaves of eggplant (Solanum melongena L. cv. Bonica) were affected by rapidly growing fruits. Plants with a fruit load showed more pronounced diurnal variation in (+ nitrate) NR activity and higher (− nitrate) NR activity than plants without fruit. The higher (− nitrate) NR activity was accompanied by higher nitrate and lower sucrose and starch contents of leaves. The more pronounced diurnal changes in (+ nitrate) NR activity were paralleled by more pronounced diurnal variation in carbohydrate content of leaves. Fruit removal led to a decrease in both (− nitrate) NR activity and nitrate concentration in leaves, while the carbohydrate content increased. Plants supplied with ammonium instead of nitrate showed only slightly lower (+ nitrate) but no (− nitrate) NR activity. As for plants treated with nitrate, diurnal changes in (+ nitrate) NR activity were most pronounced in leaves of plants with fruit and this again was paralleled by a more pronounced diurnal variation in the carbohydrate concentration in the leaves.Increasing the oxygen level of the atmosphere to 50% led to a dramatic decrease in the (+ nitrate) NR activity and to an increase in both (− nitrate) NR activity and nitrate concentration, which was accompanied by decreasing carbohydrate contents of the leaves. Low light intensities and extended dark periods caused similar changes in NR activity and nitrate and carbohydrate concentrations in leaves. Increasing the nitrate concentration in the nutrient solution led to a rise in (+ nitrate) and (− nitrate) NR activity, but only the (− nitrate) NR activity paralleled the nitrate concentration in the leaves. This increase in the nitrate concentration was accompanied by a decrease in the carbohydrate content of the leaves.It is concluded that the level of and the diurnal changes in both (+ nitrate) and (− nitrate) NR activity and the concentration of nitrate in the leaves are dependent upon their carbohydrate status.

Population variation and diurnal changes in the content of indole‐3‐acetic acid of pine seedlings (Pinus sylvestris L.) grown in a controlled environment

Pine seedlings (Pinus sylvestris L.) were grown in a growth chamber under simulated summer conditions to an age of eight weeks after the beginning of seed germination. Single seedlings were analyzed for fresh weight, shoot and root lengths, and content of indole‐3‐acetic acid (IAA). The first three variables were normally distributed with standard deviations of 29%, 17% and 18%, respectively. The IAA content had a standard deviation of 39%, and this variable was not normally distributed. If this finding is of general significance, population variation must be considered when experiments involving IAA analyses are planned, and statistical methods based on a normally distributed population cannot be used to evaluate the result of such analyses unless samples of at least 20–30 individuals are analyzed. There were no correlations between the content of IAA and any of the three other variables. The content of IAA showed pronounced diurnal changes, rising from 15 ng g−1 (fresh weight) in the morning to 42 ng g−1 in the late evening. The initial rate of change was about 10% h−1. Obviously, short‐term fluctuations must be checked if long‐term changes in IAA content are to be studied. IAA could also be released from the acidic buffer fraction by means of alkaline hydrolysis. This “bound alkali‐hydrolysable” IAA did not show short‐term fluctuations.

Seasonal shift from C3 photosynthesis to Crassulacean Acid Metabolism in Mesembryanthemum crystallinum growing in its natural environment.

Changes in δ13C value, diurnal malate content, water content and Na+, K+ and Cl- content of the annual Mesembryanthemum crystallinum (Aizoaceae) were followed in a natural population on a coastal cliff at the Mediterranean Sea shore close to Caesarea (Israel). Plants germinated in the middle of the rainy season in December 1976/January 1977. Diurnal malate fluctuations in the leaves were not detected until the end of March. Later on, at the start of the dry season, pronounced diurnal changes in malate developed. This was correlated with a progressive change in δ 13C value from about -26‰ to about -16‰ which is consistent with a change from normal C3 photosynthetic CO2 fixation to a predominantly nocturnal CO2 assimilation pattern involving Crassulacean Acid Metabolism.