Effect of Kuwait oil field fires on human comfort and environment in Jubail,Saudi Arabia

The plumes from the Kuwait oil field fires reduced hemispheric (total) solar radiation by 26–36% during January–June 1991 in Jubail (300 km SE of Kuwait City), Saudi Arabia. Residents feel noticeably cooler even though air temperatures have not been lowered significantly (up to June 1991). These observations support human comfort theories and demonstrate the importance of shade to comfort. The desirability of complete solar radiation measurements, including those of diffuse radiation, is indicated.     

The spectral distribution of biologically active solar radiation at Miami,Florida, USA

The spectral distribution of solar radiation was studied under different sky conditions during a 15-month period in Miami, Florida (USA), and over a latitudinal gradient at solar maximum. Spectroradiometric scans were characterized for total irradiance (300–3000 nm) and the relative energetic and photon contributions of the following wavelength regions: UV-B (300–320 nm); UV-A (320–400 nm); B (400–500 nm); PAR (400–700 nm); R (600–700 nm); and FR (728–732 nm). Notable results include: (i) significantly higher UV-A energy fluxes than currently in use for laboratory experiments involving the biological effects of this band-width (values ranged from 33.6 to 55.4 W/m² in Miami over the year); (ii) marked diurnal shifts in B:R and R:FR, with elevated R:FR values in early morning: (iii) a strong correlation between R:FR and atmospheric water content; and (iv) unusually high PAR values under direct sunlight with cloudy skies (2484 mol/² per s).     

Saddleback Deformities in Fish Species Collected from the Arabian Gulf Coast of Jubail City,Saudi Arabia

The saddleback syndromes were observed in several commercial fishes obtained from Saudi Arabian coast of the Arabian Gulf. These deformities resulting in missing dorsal spines or rays, sometimes accompanied by a depression in the dorsal profile, were found in ten fish species from seven families. Other morphological abnormalities such as scale disturbances, lateral line deformity, and kyphosis, the presence of a lesion, slight ambicoloration, and supraneural deformities accompanying the saddleback deformity were also observed. The occurrence of similar deformities across such a spectrum of fishes from the same location suggests that the abnormalities were induced by something in the environment common to all these species.     

Energy advantages of orientation to solar radiation in three African ruminants

Animal orientation relative to incident solar radiation allows an animal to effectively adjust the amount of radiant heat gained from an environment. Yet recent literature found ruminants to primarily orientate north/south and proposed magnetic alignment as the most parsimonious explanation. To test whether such northerly orientation has an energy advantage, we used heated cylindrical models to estimate energy costs of thermoregulation associated with north and east orientations of three species of African ruminants under cool winter conditions. Concurrent behavioural observations revealed that eland, blue wildebeest and impala did not preferentially orientate north/south during warm summer or cool winter conditions. Instead, all three species preferred to orientate perpendicular to incident solar radiation during winter and parallel to incident solar radiation during summer, throughout the day. On clear winter days with little wind, more than 60% of animal orientation preference could be accounted for by the energy savings associated with that orientation. Thus energy demands are likely to be the primary driver of animal orientation preferences.     

The effects of solar radiation on thermal comfort

The aim of this study was to investigate the relationship between simulated solar radiation and thermal comfort. Three studies investigated the effects of (1) the intensity of direct simulated solar radiation, (2) spectral content of simulated solar radiation and (3) glazing type on human thermal sensation responses. Eight male subjects were exposed in each of the three studies. In Study 1, subjects were exposed to four levels of simulated solar radiation: 0, 200, 400 and 600 Wm⁻². In Study 2, subjects were exposed to simulated solar radiation with four different spectral contents, each with a total intensity of 400 Wm⁻² on the subject. In Study 3, subjects were exposed through glass to radiation caused by 1,000 Wm⁻² of simulated solar radiation on the exterior surface of four different glazing types. The environment was otherwise thermally neutral where there was no direct radiation, predicted mean vote (PMV)=0±0.5, [International Standards Organisation (ISO) standard 7730]. Ratings of thermal sensation, comfort, stickiness and preference and measures of mean skin temperature (t_sk) were taken. Increase in the total intensity of simulated solar radiation rather than the specific wavelength of the radiation is the critical factor affecting thermal comfort. Thermal sensation votes showed that there was a sensation scale increase of 1 scale unit for each increase of direct radiation of around 200 Wm⁻². The specific spectral content of the radiation has no direct effect on thermal sensation. The results contribute to models for determining the effects of solar radiation on thermal comfort in vehicles, buildings and outdoors.     

Motility and orientation of a dinoflagellate, Gymnodinium, impaired by solar and ultraviolet radiation

Abstract The effects of solar and artificial ultraviolet radiation on the motility and orientation of the dinoflagellate Y-100 were studied. The cells show a weak photokinesis but a pronounced phototaxis which is consistently positive between 1 and 100 klx (= 4 mW m⁻² to 400 mW m⁻²); the precision of orientation increases with the fluence rate. Unfiltered solar radiation as well as artificial ultraviolet radiation reduce the percentage of motile cells increasingly with exposure time but the velocity of the still motile cells is less affected. Unirradiated control cells show a negative gravitaxis. After short exposure to solar or artificial ultraviolet radiation the precision of gravitaxis decreases and after prolonged exposure the cells start to actively move downward in the water column (positive gravitaxis). Phototaxis is also strongly impaired by ultraviolet radiation.     

Effects of artificial and solar UV-B radiation on the gravitactic orientation of the dinoflagellate, Peridinium gatunense

Abstract The effects of artificial and solar UV-B radiation on the gravitactic (formerly called geotactic) orientation of the freshwater dinoflagellate Peridinium gatunense were measured under artificial UV-B radiation and in a temperature-controlled growth chamber under solar radiation in Portugal. Circular histograms of gravitaxis show the impairement of orientation after UV irradiation. The degree of orientation, quantified using the Rayleigh test and top quadrant summation, decreased as the exposure time to the radiation prolonged. The effects of artifical UV-B radiation on orientation are stronger than those of solar radiation, probably because the radiation source emits higher fluence rates below 300 nm than found in solar radiation. After UV radiation, the gravitactic orientation under artificially increased acceleration at 2 g was drastically affected.     

铜绿微囊藻对紫外辐射的生理代谢响应

采用紫外(UV)滤膜过滤日光UV以及紫外灯添加UV的方法,研究了UV辐射对铜绿微囊藻Microcystis aeruginosa单细胞藻株PCC7806和群体藻XW01生长及生理代谢的影响。结果显示,在室内条件下低剂量UV辐射可促进群体微囊藻XW01生长;室外条件下与滤除了UV的光照相比,含有UV的完全日光更有利于微囊藻生长;而相同的UV辐射强度均导致单细胞株死亡,群体株显示了较强的UV抗性;日光中的UV可促进XW01合成抗氧化相关的超氧化物歧化酶(SOD)和过氧化氢酶(CAT)、促进胞外多糖的产生并形成较大的群体、促进UV屏障物质类菌孢素氨基酸(MAAs)和伪枝藻素(Scy)积累。这些生理代谢的改变,消除了阳光辐射中UV对微囊藻的伤害。研究的结果提示,自然条件下阳光中的UV有助于群体微囊藻生长。     

Spirochaeta smaragdinae sp. nov., a new mesophilic strictly anaerobic spirochete from an oil field

An obligately anaerobic spirochete designated strain SEBR 4228^T (T = type strain) was isolated from an oil field of Congo, Central Africa. The strain grew optimally with a sodium chloride concentration of 5% (sodium chloride concentration growth range 1.0–10%) at 37°C (growth temperature range 20–40°C) and pH of 7.0–7.2 (pH growth range pH 5.5–8.0). Strain SEBR 4228^T grew on carbohydrates (glucose, fructose, ribose, d -xylose, galactose, mannitol and mannose), glycerol, fumarate, peptides and yeast extract. Yeast extract was required for growth and could not be replaced by vitamins. It reduced thiosulfate and sulfur, to H₂S. Glucose was oxidised to lactate, acetate, CO₂ and H₂S in the presence of thiosulfate but in its absence lactate, ethanol, CO₂ and H₂ were produced. Fumarate was fermented to acetate and succinate. The G+C content of strain SEBR 4228^T was 50%. Strain SEBR 4228^T was spiral shaped measuring 5–30 by 0.3–0.5 μm and was motile with a corkscrew-like motion. Electron microscopy revealed the presence of periplasmic flagella in a 1-2-1 arrangement. Strain SEBR 4228^T possessed features typical of the members of the genus Spirochaeta . 16S rRNA sequence analysis revealed that it was closely related to Spirochaeta bajacaliforniensis (similarity 98.6%). The lack of DNA homology with S. bajacaliforniensis (38%), together with other phenotypic differences, indicated that strain SEBR 4228^T is a new species, which we have designated Spirochaeta smaragdinae . The type strain is SEBR 4228^T (= DSM 11293).     

Global solar radiation as the factor controlling induction of diapause in the pod midge (Dasyneura brassicae Winn.)

In this paper we examine the hypothesis that diapause induction in the polyvoltine pod midge Dasyneura brassicae Winn. (Diptera: Cecidomyiidae) is controlled by cumulative global solar radiation during the larval stage. The correlation between field observations of relative diapause for 3 years and four environmental factors (daylength, temperature, cumulative daylight time, and cumulative global solar radiation) was investigated. The cumulative global solar radiation during the larval stage clearly showed the strongest correlation with the observed relative diapause. It was estimated that larvae which cumulated less than 71.1 kWh m⁻² entered diapause. Compared to former theories on diapause induction in insects, this hypothesis explains how temperature and light can function together and, furthermore, it removes the requirement for biological clock involvement in diapause induction in insects. Received: 21 December 1996 / Accepted: 26 February 1997     

Effects of solar radiation and solar radiation deprived of UV-B and total UV on photosynthetic oxygen production and pulse amplitude modulated fluorescence in the brown alga Padina pavonia

Abstract: The effects of solar radiation on photosynthetic oxygen production and pulse amplitude modulated (PAM) fluorescence were measured in the marine brown macroalga Padina pavonia harvested from different depths from the Greek coast near Korinth. In fluence rate-response curves the light compensation point for photosynthetic oxygen production increased and the saturation level decreased with increasing exposure time to solar radiation. Cutting off the UV-B wavelength range (280–315 nm) from solar radiation reduced the inhibition of photosynthesis, and the organisms were less affected when all of the UV radiation was filtered out. Algae collected from 7 m depth were much more prone to photoinhibition than those harvested from rock pools exposed to unfiltered solar radiation. During continuous exposure to solar radiation, rock pool algae showed photoinhibition after longer periods of time than specimens from 7 m or from dark adapted habitats. When subjected to unfiltered solar radiation the ratio of the variable fluorescence to the maximal fluorescence     (F_v = F_m− F_o) rapidly declined with increasing exposure time. However, again algae from 7 m depth were more prone to photoinhibition than rock pool algae. The differences between the two ecological strains were less obvious when UV-B or total UV was removed from solar radiation. Only in the latter case a complete recovery was observed after 2 h while, when exposed to unifiltered sunlight, only the rock pool algae recovered completely within that time.     

Sub-aerial biofilms as blockers of solar radiation: spectral properties as tools to characterise material-relevant microbial growth

Sub-aerial biofilms (SABs) are ubiquitous microbial communities that develop at the interface between hard surfaces and the atmosphere. Inherent SAB “core-settlers” include phototrophic algae, cyanobacteria, heterotrophic bacteria and microcolonial fungi (MCF). SABs do not simply cover hard surfaces; they interact with them in myriads of ways and bind to the underlying substrate. Secretion of extracellular mucilage aids adhesion, while organic acids and acidic polysaccharides weather the surface. As protection against solar radiation, many members of the SAB consortia produce shielding pigments while the phototrophic inhabitants are laden with photosynthetic pigments. All absorb light of many wavelengths and in addition, the cells themselves scatter light. Both effects change the spectra of incoming radiation (including wavelengths that are converted to electricity by photovoltaic cells) and decrease its intensity. To quantify these effects on SABs as complex entities of organisms and pigments, we measured the spectral properties of model and natural biofilms transferred to glass. Here we show that SABs growing on solar panels and other substrates scatter incident radiation between 250 nm up to 1800 nm and block up to 70% of its transmission. Model biofilms have the advantage that their microbial components can be “tuned” to resemble natural ones of different compositions thus providing a novel materials-testing tool.     

Mycoremediation of crude oil contaminated soil by specific fungi isolated from Dhahran in Saudi Arabia

Crude oil biodegrading microorganism considers the key role for environmental preserving. In this investigation, crude oil biodegrading fungal strains have been isolated in polluted soil of crude-oil at khurais oil ground in Kingdom of Saudi Arabia. Among of 22 fungal isolates, only three isolates reflected potential capability for oil degradation. These isolates were identified and submitted to GenBank as (A1) Aspergillus polyporicola (MT448790), (A2) Aspergillus spelaeus (MT448791) and (A3) Aspergillus niger (MT459302) through internal-transcribed spacer-regions (ITS1&ITS2) for sequencing in molecular marker. Comparing with controls, strain (A1) Aspergillus niger was superior for biodegradation ability (58%) comparing with Aspergillus polyporicola and Aspergillus spelaeus degrading were showed 47 and 51% respectively. Employed CO₂ evolution as indicator for petroleum oil biodegradation by the fungal isolates reflected that, Aspergillus niger emission highest CO2 (28.6%) comparing with Aspergillus spelaeus and Aspergillus polyporicola which showed 13% and 12.4% respectively. capability of Aspergillus sp. to tolerate and adapted oil pollutants with successful growth rate on them, indicated that it can be employed as mycoremediation agent for recovering restoring ecosystem when contaminated by crude oil.     

Effects of solar and ultraviolet radiation on motility, photomovement and pigmentation in filamentous, gliding cyanobacteria

Abstract The effects of solar irradiation and artificial UV irradiation on several cyanobacteria ( Anabaena variabilis and two strains of Phormidium uncinatum ) have been studied. Both types of radiation affect the percentage of motile filaments and impair the linear velocity of the organisms. Long term exposure to UV radiation bleaches the photosynthetic pigments as determined by absorption difference spectra. Fluorescence excitation and emission spectra indicate that under ultraviolet radiation the energy transfer from the accessory pigments to chlorophyll is affected. Furthermore the structural integrity of the phycobilisomes seems to be impaired by continuous radiation and the photoreceptor pigments seem to be destroyed.     

Photoinhibition by solar radiation in the Mediterranean alga Peyssonnelia squamata measured on site

Photoinhibition of photosynthesis, defined as reversible decrease in the effective photosynthetic quantum yield, was measured in the Mediterranean red alga, Peyssonnelia squamata, using pulse amplitude modulation (PAM) chlorophyll fluorescence and oxygen production on site. This alga is adapted to very low fluence rates of solar radiation and is easily inhibited by exposure to excessive radiation. At high solar angles its photosynthetic capacity is impaired even in its natural habitat, in the protective shade of overhanging rocks. Oxygen production was maximal at 5 m depth and decreased to almost zero at the surface. When exposed at the surface oxygen production ceased within 16 min. The optimal photosynthetic quantum yield, defined as Fv/Fm, was about 0.45 in dark-adapted specimens. After 30 min of exposure to unattenuated solar radiation the (effective, Fv/Fm) quantum yield decreased to below 0.1. Removing solar UV (especially UV-B) significantly reduced photoinhibition: the quantum yield of a sample exposed under a UV-B cut-off filter was double that of a sample exposed to full solar radiation after 30 min exposure. Recovery from photoinhibition took several hours and was not complete after prolonged exposure (1.5 h) to direct solar radiation. The degree of photoinhibition depended on the depth at which the thalli were exposed. Recovery from photoinhibition was complete within 2 h except when the algae were exposed at the surface. When measured over the whole day, the effective photosynthetic quantum yield significantly decreased by about 25% from initially high values toward early afternoon and rose again towards evening. The data indicate that this alga is adapted to very low irradiances and is easily inhibited by excessive solar radiation; solar UV contributes substantially to the observed photoinhibition.     

Exposure to solar radiation increases damage to both host tissues and algal symbionts of corals during thermal stress

Elevated seawater temperatures have long been accepted as the principal stressor causing the loss of symbiotic algae in corals and other invertebrates with algal symbionts (i.e., bleaching). A secondary factor associated with coral bleaching is solar irradiance, both its visible (PAR: 400–700 nm) and ultraviolet (UVR: 290–400 nm) portions of the spectrum. Here we examined the synergistic role of solar radiation on thermally induced stress and subsequent bleaching in a common Caribbean coral, Montastraea faveolata. Active fluorescent measurements show that steady-state quantum yields of photosystem II (PSII) fluorescence in the zooxanthellae are markedly depressed when exposed to high solar radiation and elevated temperatures, and the concentration of D1 protein is significantly lower in high light when compared to low light treatments under the same thermal stress. Both photosynthetic pigments and mycosporine-like amino acids (MAAs) are also depressed after experimental exposure to high solar radiation and thermal stress. Host DNA damage is exacerbated under high light conditions and is correlated with the expression of the cell cycle gene p 53, a cellular gatekeeper that modulates the fate of damaged cells between DNA repair processes and apoptotic pathways. These markers of cellular stress in the host and zooxanthellae have in common their response to the enhanced production of reactive oxygen species during exposure to high irradiances of solar radiation and elevated temperatures. Taking these results and previously published data into consideration, we conclude that thermal stress during exposure to high irradiances of solar radiation, or irradiances higher than the current photoacclimatization state, causes damage to both photochemistry and carbon fixation at the same time in zooxanthellae, while DNA damage, apoptosis, or necrosis are occurring in the host tissues of symbiotic cnidarians.Abbreviations _PSII Functional absorption cross-section for PSII - F_o, F_m Minimum and maximum yields of chlorophyll a fluorescence measured after dark acclimation (relative units) - F_v Variable fluorescence after dark acclimation (=F_m–F_o), dimensionless - F_v/F_m Maximum quantum yield of photochemistry in PSII measured after dark acclimation, dimensionless - F, F_m Steady-state and maximum yields of chlorophyll a fluorescence measured under ambient light (relative units) - F/F_m Quantum yield of photochemistry in PSII measured at steady state under ambient light Communicated by R.C. Carpenter     

Modulation of the bacterial response to spectral solar radiation by algae and limiting nutrients

SUMMARY 1. The response of bacterial production (measured as [³H]TdR incorporation rate) to spectral solar radiation was quantified experimentally in an oligotrophic high-mountain lake over 2 years. Bacterial responses were consistent: ultraviolet-B (UVB) was harmful, whereas ultraviolet-A (UVA) + photosynthetically active radiation (PAR) and PAR enhanced bacterial activity. Full sunlight exerted a net stimulatory effect on bacterial activity in mid-summer but a net inhibitory effect towards the end of the ice-free period.
2. Experiments were undertaken to examine whether the bacterial response pattern depended on the presence of algae and/or was modulated by the availability of a limiting inorganic nutrient (phosphorus, P). In the absence of algae, [³H]TdR incorporation rates were significantly lower than when algae were present under all light treatments, and the consistent bacterial response was lost. This suggests that the bacterial response to spectral solar radiation depends on fresh-C released from algae, which determines the net stimulatory outcome of damage and repair in mid-summer.
3. In the absence of algae, UVB radiation inhibited bacteria when they were strongly P-deficient (mean values of N : P ratio: 46.1), whereas it exerted no direct effect on bacterial activity when they were not P-limited.
4. P-enrichment of lake water markedly altered the response of bacteria to spectral solar radiation at the end of ice-free period, when bacteria were strongly P-deficient. Phosphorus enrichment suppressed the inhibitory effect of full sunlight that was observed in October, both in whole lake water (i.e. including algae) and in the absence of algae. This indicates that the bacterial P-deficiency, measured as the cellular N : P ratio, was partly responsible for the net inhibitory effect of full sunlight, implying a high bacterial vulnerability to UVB.     

Determinants of bovine thermal response to heat and solar radiation exposures in a field environment

Continuous exposure of cattle to summer heat in the absence of shade results in significant hyperthermia and impairs growth and general health. Reliable predictors of heat strain are needed to identify this condition. A 12-day study was conducted during a moderate summer heat period using 12 Angus x Simmental (Bos taurus) steers (533 ± 12 kg average body weight) to identify animal and ambient determinations of core body temperature (T _core) and respiration rate (RR) responses to heat stress. Steers were provided standard diet and water ad libitum, and implanted intraperitoneally with telemetric transmitters to monitor T _core hourly. Visual count of flank movement at 0800 and 1500 hours was used for RR. Dataloggers recorded air temperature (T _a), and black globe temperatures (T _bg) hourly to assess radiant heat load. Analysis was across four periods and 2 consecutive days averaged within each period. Average T _a and T _bg increased progressively from 21.7 to 30.3°C and 25.3 to 34.0°C, respectively, from the first to fourth periods. A model utilizing a quadratic function of T _a explained the most variation in T _core (R ² = 0.56). A delay in response from 1 to 3 h did not significantly improve R ² for this relationship. Measurements at 0800 and 1500 hours alone are sufficient to predict heat strain. Daily minimum core body temperature and initial 2-h rise in T _a were predictors of maximum core temperature and RR. Further studies using continuous monitoring are needed to expand prediction of heat stress impact under different conditions.