Winter Temperature Conditions Research Articles

Transcriptome analysis of chrysanthemum (Dendranthema grandiflorum) in response to low temperature stress

BackgroundChrysanthemum is one kind of ornamental plant well-known and widely used in the world. However, its quality and production were severely affected by low temperature conditions in winter and early spring periods. Therefore, we used the RNA-Seq platform to perform a de novo transcriptome assembly to analyze chrysanthemum (Dendranthema grandiflorum) transcription response to low temperature.ResultsUsing Illumina sequencing technology, a total of 86,444,237 high-quality clean reads and 93,837 unigenes were generated from four libraries: T01, controls; T02, 4 °C cold acclimation (CA) for 24 h; T03, − 4 °C freezing treatments for 4 h with prior CA; and T04, − 4 °C freezing treatments for 4 h without prior CA. In total, 7583 differentially expressed genes (DEGs) of 36,462 annotated unigenes were identified. We performed GO and KEGG pathway enrichment analyses, and excavated a group of important cold-responsive genes related to low temperature sensing and signal transduction, membrane lipid stability, reactive oxygen species (ROS) scavenging and osmoregulation. These genes encode many key proteins in plant biological processes, such as protein kinases, transcription factors, fatty acid desaturase, lipid-transfer proteins, antifreeze proteins, antioxidase and soluble sugars synthetases. We also verified expression levels of 10 DEGs using quantitative real-time polymerase chain reaction (qRT-PCR). In addition, we performed the determination of physiological indicators of chrysanthemum treated at low temperature, and the results were basically consistent with molecular sequencing results.ConclusionIn summary, our study presents a genome-wide transcript profile of Dendranthema grandiflorum var. jinba and provides insights into the molecular mechanisms of D. grandiflorum in response to low temperature. These data contributes to our deeper relevant researches on cold tolerance and further exploring new candidate genes for chilling-tolerance and freezing-tolerance chrysanthemum molecular breeding.

Warmer winters reduce the advance of tree spring phenology induced by warmer springs in the Alps

Mountain regions are particularly susceptible and influenced by the effects of climate change. In the Alps, temperature increased two times faster than in the Northern Hemisphere during the 20th century. As an immediate response in certain tree species, spring phenological phases, such as budburst and flowering, have tended to occur earlier. However, recent studies have shown a slowing down of phenological shifts during the last two decades compared to earlier periods, which might be caused by warmer winters. Indeed, cold temperatures are required to break bud dormancy that occurs in early fall; and dormancy break is a prerequisite for cell elongation to take place in spring when temperature conditions are warm enough.Here we aimed at evaluating the effects of winter warming vs. spring warming on the phenological shift along mountain elevation gradients. We tested the hypothesis that a lack of chilling temperature during winter delayed dormancy release and subsequently spring phenological phases. For this, we used eight years of temperature and phenological records for five tree species (Betula pendula, Fraxinus excelsior, Corylus avellana, Picea abies and Larix decidua) gathered with the citizen science program Phenoclim (www.phenoclim.org) deployed over the French Alps.Our results showed that for similar preseason (i.e. after dormancy break) temperatures, warmer winters significantly delayed budburst and flowering along the elevation gradient (+0.9 to +5.6 days °C−1) except for flowering of Corylus and budburst of Picea. For similar cold winter temperatures, warmer preseasons significantly advanced budburst and flowering along the elevation gradient (−5.3 to −8.4 days °C−1). On average, the effect of winter warming was 2.3 times lower than the effect of spring warming. We also showed that warmer winter temperature conditions have a significantly larger effect at lower elevations.As a consequence, the observed delaying effect of winter warming might be beneficial to trees by reducing the risk of exposure to late spring frost on a short term. This could further lead to partial dormancy break at lower elevations before the end of the 21st century, which, in turn, may alter bud development and flowering and so tree fitness.

Winter temperature conditions (1670–2010) reconstructed from varved sediments, western Canadian High Arctic

Advances in paleoclimatology from the Arctic have provided insights into long-term climate conditions. However, while past annual and summer temperature have received considerable research attention, comparatively little is known about winter paleoclimate. Arctic winter is of special interest as it is the season with the highest sensitivity to climate change, and because it differs substantially from summer and annual measures. Therefore, information about past changes in winter climate is key to improve our knowledge of past forced climate variability and to reduce uncertainty in climate projections. In this context, Arctic lakes with snowmelt-fed catchments are excellent potential winter climate archives. They respond strongly to snowmelt-induced runoff, and indirectly to winter temperature and snowfall conditions. To date, only a few well-calibrated lake sediment records exist, which appear to reflect site-specific responses with differing reconstructions. This limits the possibility to resolve large-scale winter climate change prior the instrumental period.Here, we present a well-calibrated quantitative temperature and snowfall record for the extended winter season (November through March; NDJFM) from Chevalier Bay (Melville Island, NWT, Canadian Arctic) back to CE 1670. The coastal embayment has a large catchment influenced by nival terrestrial processes, which leads to high sedimentation rates and annual sedimentary structures (varves). Using detailed microstratigraphic analysis from two sediment cores and supported by μ-XRF data, we separated the nival sedimentary units (spring snowmelt) from the rainfall units (summer) and identified subaqueous slumps. Statistical correlation analysis between the proxy data and monthly climate variables reveals that the thickness of the nival units can be used to predict winter temperature (r = 0.71, pc < 0.01, 5-yr filter) and snowfall (r = 0.65, pc < 0.01, 5-yr filter) for the western Canadian High Arctic over the last ca. 400 years. Results reveal a strong variability in winter temperature back to CE 1670 with the coldest decades reconstructed for the period CE 1800–1880, while the warmest decades and major trends are reconstructed for the period CE 1880–1930 (0.26°C/decade) and CE 1970–2010 (0.37°C/decade). Although the first aim of this study was to increase the paleoclimate data coverage for the winter season, the record from Chevalier Bay also holds great potential for more applied climate research such as data-model comparisons and proxy–data assimilation in climate model simulations.

Interactive effects of nutrient availability, temperature, and irradiance on photosynthetic pigments and color of the brown alga Undaria pinnatifida

Color is one of the important factors that determine the commercial value of cultivated marine macroalgae such as the brown alga Undaria pinnatifida (Laminariales; Phaeophyta) in Japan. Macroalgal color is fundamentally derived from the algal photosynthetic pigment content, which is affected by abiotic factors. However, little is known about the quantitative relationship between pigment content and color and the direct effects of abiotic factors on the color of marine macroalgae. We conducted a 24-day indoor culture experiment to assess the combined effects of nutrient availability (enriched and nonenriched seawater), seawater temperature (15 and 5 °C), and irradiance (180 and 30 μmol photons m−2 s−1) on the concentrations of six pigments (chlorophyll (Chl) a, Chl c 1, Chl c 2, fucoxanthin, violaxanthin, and zeaxanthin) and three color values (lightness L*, redness a*, and yellowness b*) of U. pinnatifida sporophytes. Negative correlations between pigment content and color values of the cultured algae were detected. Reduced nutrient availability, decrease in temperature, and elevated irradiance resulted in decreased pigment contents and increased color values. Moreover, a significant interaction between nutrient availability and temperature indicated that the positive effect of nutrient enrichment was antagonized by a decrease in temperature. These results suggest that U. pinnatifida can discolor under nutrient-poor, winter temperature, and saturated irradiance conditions. To increase the commercial value of this species, artificial nutrient enrichment during spring or cultivation from a deeper depth may be effective.

Long-term dynamics of nival processes in the Khibiny Mountains

Period of warming is registered at Khibiny Mountains in the end of XX century. Sensible rise in temperature occur in winter. The one of general indicators of present climate changes is multiyear dynamic of nival processes not only for contrast high-mountain conditions but also for more temperate green belt. Compatible variability of both data sets from high-mountain (1050 m) and green belt (320 m) stations allows to full appreciation of present changes. The results of data evaluation shows stability of snow cover characteristics against changing of winter temperature conditions and avalanche activity.

Thermal adaptation and thermal environment in university classrooms and offices in Harbin

To study the influences of indoor and outdoor climate on thermal adaptation, a field study was conducted in classrooms and offices in winter and spring. The thermal environment parameters in the classrooms and offices were tested during the survey, while the subjects were interviewed on their thermal responses. The results showed that human thermal sensations were related to both indoor and outdoor climates. The neutral temperatures were not the same under different indoor temperature conditions in winter. The indoor microclimates had influences on human adaptability; the thermal neutral temperature was close to the indoor mean air temperature in thermal comfort environments. However, people felt hot when the indoor temperature was high and beyond the comfort zone in winter. Because the winter is long and outdoor temperature is low in Harbin, people have adapted to the cold environment. The indoor temperature should be kept at the lower limit of the comfort range in winter to keep human comfort and save energy. The neutral temperatures were different in winter and spring which proved that the outdoor climate influenced human adaptation. The indoor temperature in winter is suggested lower than that in spring, which is a comfortable and energy efficient regulation strategy. According to the regulation strategy, about 9.6% energy for centralized heating system can be saved.

Exploring bud dormancy completion with a combined architectural and phenological analysis: The case of apple trees in contrasting winter temperature conditions

The branching pattern and phenology of trees result from interactions between the tree's genetic constitution and environmental conditions. Temperature strongly affects the duration of bud dormancy and further shoot growth. Our hypothesis was that shoot architecture is strongly affected by winter temperatures determining both the position and budburst of vegetative laterals with a lower effect on their outgrowth. The study was conducted on four apple cultivars characterized by various chilling requirements and grown in two contrasting winter temperature conditions. A two-step approach was designed to quantify at the shoot scale first the branching pattern and second two phenological stages of vegetative laterals, budburst and outgrowth. A categorical variable, the branching zone, was built to summarize the lateral position along the shoot. It was integrated into the phenological analysis as a factor together with the cultivar and the winter temperature. Temperature had a main effect on the distribution of vegetative laterals along the shoot. It also strongly affected budburst, which was also affected by the cultivar and the branching zone. The outgrowth of the lateral was not significantly affected by temperature but was significantly affected by the cultivar and the branching zone. Furthermore, the delayed senescence and subsequent leaf persistence during winter, characterizing the apple tree in the mild winter temperature condition, had only a weak effect on the distribution of vegetative laterals and on budburst and lateral outgrowth. The actual shoot architecture and budburst result from an ordered sequence of events with a pivotal role of winter temperatures on the dormancy completion of individual lateral buds. Endogenous factors related to the cultivar branching pattern overtake the temperature effect on the lateral outgrowth.

Assessment of stability of drug biomarkers in municipal wastewater as a factor influencing the estimation of drug consumption using sewage epidemiology

Stability of the selected urinary biomarkers of six illicit drugs and two therapeutic opioids in municipal wastewater was studied in order to determine errors associated with their possible transformation in the sewer. The stability was assessed in experiments conducted at 10°C and 20°C in order to simulate typical winter and summer temperature conditions in the sewer system. Among fourteen substances tested, the most unstable compounds were morphine-3-β-D glucuronide (MG), 6-acetyl morphine (6-AM), cocaine (COC) and 6-acetyl codeine (6-AC), while all other investigated compounds appeared to be relatively stable over a period of 72h. The transformation of all degradable compounds followed pseudo-first order kinetics with significantly longer half-times (t1/2) at winter conditions. At 20°C, t1/2 of MG, 6-AM, COC and 6-AC was 7h, 87h, 35h and 58h, respectively, while the corresponding t1/2 values at 10°C were 18h, 139h, 173h and 87h. The main transformation mechanism of MG, 6-AM and 6-AC was most probably their enzymatic hydrolysis to morphine (MOR) and codeine (COD), while COC transformation to benzoylecgonine (BE) was primarily governed by chemical hydrolysis. The results indicate that the effect of the observed transformation of urinary biomarkers of COC and 6-AM on the estimates of COC and heroin consumption are relatively small (<10%) if the in-sewer hydraulic retention time is lower than 12h. Acidification of the wastewater samples proved to be the good way to stabilise the wastewater samples for the analysis of all selected compounds, except for 11-nor-9-carboxy-∆9-tetrahydrocannabinol (THC-COOH). This finding should be taken into account when selecting the preservation technique for multiresidual analyses of different groups of illicit drugs.

Viability of Puccinia horiana Teliospores Under Various Environmental Conditions

Puccinia horiana Henn. is a quarantine-significant fungal pathogen and causal agent of chrysanthemum white rust (CWR). The pathogen and disease were first discovered in the United States in 1977 and quickly eradicated. During the early 1990s, CWR reemerged in several instances, but in each instance was declared eradicated. However, since approximately 2004 CWR has reappeared at an accelerated frequency. This has suggested that either P. horiana is entering the country more frequently from foreign locations or that P. horiana is now established in the field, implying that spores are capable of surviving winter conditions in plant debris or soil. As a result of the possibility that the pathogen has become established in the United States, we initiated several lines of research. The objectives of the study reported here were: (i) develop a better and more sensitive method to measure teliospore longevity; and (ii) determine if the pathogen is able to survive northeastern winters as viable teliospores. Results from the study showed that teliospores survived in the greenhouse a maximum of 28 days in dry soil and 7 days in moist soil. In a growth chamber simulating winter temperature conditions in the northeastern United States, teliospores survived a maximum of 35 days. It was concluded that P. horiana teliospores are not able to survive through typical northeastern U.S. winters. Accepted for publication 9 January 2014. Published 18 March 2014.

Monitoreo energético experimental de vivienda unifamiliar compacta en un clima templado frio de Argentina

En el presente trabajo se estudia el comportamiento térmico-energético de viviendas compactas entre medianeras implantadas en barrios residenciales de baja densidad en la ciudad de Santa Rosa, La Pampa, Argentina (latitud: 36º27'S y longitud: 64º27'W). Los objetivos son evaluar la temperatura interior y las condiciones de confort en invierno a través del monitoreo experimental y analizar el consumo histórico de gas natural en calefacción. Los resultados muestran que las viviendas compactas entre medianeras tienen un 50% menos de consumo de gas natural que la vivienda social unifamiliar en la misma región en estudio. El panorama energético de Argentina, la posibilidad de revisar Normativas y Códigos de Edificación, la tendencia del crecimiento de la construcción de viviendas en la región en estudio, el proceso de etiquetado de la edificación, entre otros aspectos, ameritan un análisis de la información de las características del stock de las edificios y de su performance energética. La creación de un protocolo de monitoreo armonizado de datos es imperativa.

The invertebrate fauna of anthropogenic soils in the High-Arctic settlement of Barentsburg, Svalbard

The terrestrial environment of the High Arctic consists of a mosaic of habitat types. In addition to the natural habitat diversity, various human-influenced types may occur. For the resident invertebrate fauna, these anthropogenic habitats may be either unusually favourable or detrimental. In the town of Barentsburg, Svalbard, soils were imported for the greenhouses from southern Russia. These soils were subsequently discarded outside the greenhouses and have become augmented with manure from the cowsheds. Both the greenhouse and the cowsheds are now derelict. This site represents an unusually nutrient-rich location with considerable development of organic soils, in stark contrast to the naturally forming organic soils in Svalbard, which are typically thin and nutrient poor. Few previous studies have examined the soil invertebrate communities of human-disturbed or -created habitats in the Arctic. In an often nutrient-poor terrestrial environment, it is unclear how the invertebrate fauna will react to such nutrient enhancement. In these soils, 46 species of invertebrates were determined. Eleven species have not been recorded from other habitats in Svalbard and are hence likely to have been introduced. The native species assemblage in the anthropogenic soils was not atypical for many natural sites in Svalbard. Despite the enriched organic soils and highly ameliorated winter temperature conditions, the soil invertebrate fauna biodiversity does not appear to be enhanced beyond the presence of certain probably introduced species. Keywords: Collembola; Enchytraeidae; Lumbricidae; Chironomidae; Oribatida; Gamasida (Published: 17 May 2013) Citation: Polar Research 2013, 32 , 19273, http://dx.doi.org/10.3402/polar.v32i0.19273

Climate and weather influences on spatial temporal patterns of mountain pine beetle populations in Washington and Oregon

Widespread outbreaks of mountain pine beetle in North America have drawn the attention of scientists, forest managers, and the public. There is strong evidence that climate change has contributed to the extent and severity of recent outbreaks. Scientists are interested in quantifying relationships between bark beetle population dynamics and trends in climate. Process models that simulate climate suitability for mountain pine beetle outbreaks have advanced our understanding of beetle population dynamics; however, there are few studies that have assessed their accuracy across multiple outbreaks or at larger spatial scales. This study used the observed number of trees killed by mountain pine beetles per square kilometer in Oregon and Washington, USA, over the past three decades to quantify and assess the influence of climate and weather variables on beetle activity over longer time periods and larger scales than previously studied. Influences of temperature and precipitation in addition to process model output variables were assessed at annual and climatological time scales. The statistical analysis showed that new attacks are more likely to occur at locations with climatological mean August temperatures >15 degrees C. After controlling for beetle pressure, the variables with the largest effect on the odds of an outbreak exceeding a certain size were minimum winter temperature (positive relationship) and drought conditions in current and previous years. Precipitation levels in the year prior to the outbreak had a positive effect, possibly an indication of the influence of this driver on brood size. Two-year cumulative precipitation had a negative effect, a possible indication of the influence of drought on tree stress. Among the process model variables, cold tolerance was the strongest indicator of an outbreak increasing to epidemic size. A weather suitability index developed from the regression analysis indicated a 2.5x increase in the odds of outbreak at locations with highly suitable weather vs. locations with low suitability. The models were useful for estimating expected amounts of damage (total area with outbreaks) and for quantifying the contribution of climate to total damage. Overall, the results confirm the importance of climate and weather on the spatial expansion of bark beetle outbreaks over time.

Low temperature tolerance and starvation ability of the oak processionary moth: implications in a context of increasing epidemics

We investigated how modifications in winter and spring temperature conditions may affect the survival of a spring‐hatching Lepidoptera, the oak processionary moth Thaumetopoea processionea. Supercooling and chilling injury experiments indicate that eggs are especially cold hardy at the start of the winter period, although this ability is reduced later in the season. In the spring, young larvae are sufficiently cold hardy to ensure no direct mortality as a result of late frosts. A comparison of phenological models shows that neonate larvae may await the unfolding of new oak leaves for relatively long periods (e.g. 1–30 days). Under both low (4°C after 5 days at 16°C) and high temperature experimental scenarios (constant 16°C), the majority of neonate larvae can survive starvation for more than 2 weeks. Larvae may also suffer from food depletion once their development has been initiated (e.g. during cold springs) if the threshold temperature for feeding is not reached for several consecutive days, or in the case of late frosts affecting foliage availability. When temperature is reduced to 4°C, developing larvae become inactive and do not feed anymore; their starvation survival capability is reduced to approximately 2 weeks (cold spring hypothesis). At 16°C, developing larvae that are deprived of food can only survive for 10 days (late frost hypothesis). We conclude that, in the oak processionary moth, neonate larvae are relatively well adapted to early hatching relative to budburst, ensuring them the highest foliage quality for development. In some years, however, phenological asynchrony or cold spring conditions may affect the persistence of populations at the limits of the species' range.

Differences in sensitivity of native and exotic fish species to changes in river temperature

Abstract This paper describes the effects that temperature changes in the Rhine river distributaries have on native and exotic fish diversity. Site-specific potentially affected fractions (PAFs) of the regional fish species pool were derived using species sensitivity distributions (SSDs) for water temperature. The number of fish species in the river distributaries has changed remarkably over the last century. The number of native rheophilous species declined up until 1980 due to anthropogenic disturbances such as commercial fishing, river regulation, migration barriers, habitat deterioration and water pollution. In spite of progress in river rehabilitation, the native rheophilous fish fauna has only partially recovered thus far. The total number of species has strongly increased due to the appearance of more exotic species. After the opening of the Rhine-Main-Danube waterway in 1992, many fish species originating from the Ponto-Caspian area colonized the Rhine basin. The yearly minimum and maximum river temperatures at Lobith have increased by circa 4 0C over the period 1908-2010. Exotic species show lower PAFs than native species at both ends of the temperature range. The interspecific variation in the temperature tolerance of exotic fish species was found to be large. Using temporal trends in river temperature allowed past predictions of PAFs to demonstrate that the increase in maximum river temperature negatively affected a higher percentage of native fish species than exotic species. Our results support the hypothesis that alterations of the river Rhine’s temperature regime caused by thermal pollution and global warming limit the full recovery of native fish fauna and facilitate the establishment of exotic species which thereby increases competition between native and exotic species. Thermal refuges are important for the survival of native fish species under extreme summer or winter temperature conditions.

Energy in New Zealand houses: comfort, physics and consumption

The Household Energy End-use Study (HEEP) quantified how, where, when, and why energy was used in New Zealand houses based on the monitoring of energy and end-uses in a national sample of 400 houses. Based on these data, space heating was found to average 34% of total household energy use. Three issues are highlighted in relation to space heating: firstly, the extent to which low indoor temperatures are associated with persistent under-heating; secondly, whether some space-heating sources tend to be associated with higher (or lower) winter indoor temperatures than others; and thirdly, what the drivers of under-heating might be. An overview of the HEEP research and its complex data set is provided. The range of winter indoor temperatures are then compared with international benchmarks and established healthy temperature ranges. Occupants’ perceptions of winter indoor temperature conditions are presented and explored in relation to heating patterns and household energy consumption. The impacts of this research have assisted in changing public policy, moving from a narrow focus on energy efficiency toward an integrated energy, environmental, and health policy for the building stock and future interventions. L'Etude sur l'Utilisation Finale de l'Energie par les Ménages (HEEP) a quantifié comment, où, quand et pourquoi il a été utilisé de l’énergie dans les maisons de Nouvelle-Zélande, en se basant sur un suivi de l’énergie et des utilisations finales dans un échantillon national de 400 maisons. Sur la base de ces données, il a été constaté que le chauffage des volumes s’élevait en moyenne à 34% de l'utilisation totale de l’énergie domestique. Trois problèmes sont mis en évidence par rapport au chauffage des volumes: premièrement, il s'agit de savoir dans quelle mesure des températures intérieures basses sont associées à une insuffisance de chauffage persistante; deuxièmement, il s'agit de savoir si certaines sources de chauffage des volumes ont, plus que d'autres, tendance à être associées à des températures hivernales intérieures plus élevées (ou plus basses); et troisièmement, il s'agit de savoir ce que pourraient être les facteurs causant cette insuffisance de chauffage. Un panorama de l’étude HEEP et de ses données complexes est fourni. Les plages relatives aux température hivernales intérieures sont ensuite comparées aux données de référence internationales et aux plages de température admises comme bonnes pour la santé. La manière dont les occupants perçoivent les conditions de température hivernales intérieures est présentée et examinée par rapport aux habitudes de chauffage et à la consommation d’énergie par les ménages. Les répercussions de ces recherches ont contribué à modifier les politiques publiques, en évoluant d'une approche étroite axée sur le rendement énergétique à une politique énergétique, environnementale et de santé intégrée concernant le parc bâti et les opérations futures. Mots clés: performances des bâtiments, parc bâti, température demandée, précarité énergétique, logement, comportement des habitants, utilisation de l’énergie par les ménages, chauffage des volumes, Nouvelle-Zélande

Feeding rates in the sailfin molly Poecilia latipinna and its coexisting sexual parasite, the gynogenetic Amazon molly Poecilia formosa

Feeding rates of the gynogenetic Amazon molly Poecilia formosa and one of its sexual hosts, the sailfin molly Poecilia latipinna, were measured under winter and summer temperature conditions. Food consumption of the unisexual P. formosa in winter conditions was significantly higher than that of P. latipinna, and it is hypothesized that the resulting food stress might have an important influence on the population composition of these closely related fishes via higher winter mortality in P. formosa.

Thermal biology, torpor use and activity patterns of a small diurnal marsupial from a tropical desert: sexual differences

Many small desert dasyurids employ torpor almost daily during winter, because cold nights and low food availability impose high energetic costs. However, in Western Australia the arid zone extends into tropical, coastal regions, where winter temperature conditions are far less severe. We studied the thermal biology and activity patterns of free-ranging kaluta (approximately 27 g), a dasyurid restricted to these tropical spinifex deserts, during the Austral winter (June-July) and in addition quantified activity patterns in captivity. Unlike most dasyurids, wild and captive kalutas were almost exclusively diurnal and retreated into underground burrows during the night. Despite being active during the warmer part of the day, kalutas entered torpor daily. However, torpor patterns differed remarkably between males and females. While females spent most of the night torpid at body temperatures (T (b)) as low as 21 degrees C, close to soil temperature, males entered multiple short and shallow bouts (T (b) > 25 degrees C) during the night. Males also maintained higher T (b)s during the early morning when active, occupied larger home ranges and covered greater distances while foraging than females. Hence, males appear to expend more energy than the similar-sized females both while foraging and during the rest phase. We propose that physiological as well as behavioural preparations for the September mating season that culminate in a complete male die-off might already impose energetic costs on males during winter.

Glacio-meteorological conditions in the vicinity of the Belgian Princess Elisabeth Station, Antarctica

During two consecutive reconnaissance surveys in 2004 and 2005 and a revisit in 2008, the glaciological and meteorological conditions in the vicinity of the new Belgian Princess Elisabeth Station (71857'S; 23820'E) on Utsteinen Ridge were investigated. We set up an automatic weather station, measured the ice thickness around the Utsteinen Ridge, and established a mass balance stake network. These baseline investigations show that Utsteinen Ridge is a relatively sheltered spot from the main katabatic winds. Furthermore, winter temperature conditions are rather mild, confirming the coreless winter conditions of the Antarctic ice sheet. Mass balance is generally low (near zero) with a small accumulation to the east and relatively little ablation to the west of Utsteinen Ridge. Ice flow in the vicinity of the station is also minimal, since the Sor Rondane Mountains upstream of the station block most of the ice flow, a feature that is most apparent in the area where the station is situated. Measurements of the surface topography separated by four years show that the construction of the station seems to have a limited effect on the redistribution of snow around it. In view of the sheltered and safe ice conditions, the area is an ideal place for deploying field activities. Received 13 February 2009, accepted 19 June 2009

Viability of Phakopsora pachyrhizi Urediniospores Under Simulated Southern Louisiana Winter Temperature Conditions.

Soybean rust, caused by Phakopsora pachyrhizi, originally occurred in Asia. It has now spread to South America and the continental United States. This disease has the potential to cause severe economic losses to U.S. soybean growers, especially in the south, where the environmental conditions are more favorable to P. pachyrhizi survival during winter. In the present study, the effect of simulated southern Louisiana winter temperature conditions (12°C, 14-h days and 1°C, 10-h nights with 75% relative humidity) on soybean rust urediniospore viability was examined. It was found that urediniospore viability declined rapidly from 72 to 40% after 1 day and then decreased gradually to 17% after 7 days and 11% after 60 days. Spores stored under southern Louisiana winter conditions for 60 days still produced pustules on inoculated leaves. In comparison, the viability of spores stored at room temperature decreased gradually and reached 0% at the end of 60 days. Winter temperature treatment not only reduced spore viability but also decreased germ tube growth. In addition, soybean rust spores recovered from overwintered dry kudzu leaves were also found viable. This study indicates that soybean rust spores could survive southern Louisiana winter conditions and initiate a new cycle of infection in the next growing season.

The North Atlantic Oscillation and European vegetation dynamics

AbstractThe relationship between vegetation greenness and the North Atlantic Oscillation (NAO) is assessed over Europe. The study covers the 21‐year period from 1982 to 2002 and is based on monthly composites of the Normalised Difference Vegetation Index (NDVI) and Brightness Temperature from the Global Inventory Monitoring and Modelling System (GIMMS) as well as on monthly precipitation from the Global Precipitation Climatology Centre (GPCC).A systematic analysis is first performed of point correlation fields over the 21‐year period between the winter NAO index and spring and summer NDVI, followed by an assessment of the vegetation response to precipitation and temperature conditions in winter, over two contrasting regions, namely the Iberian Peninsula and Northeastern Europe. Finally, the impact of NAO on vegetation dynamics over the two regions is evaluated by studying the corresponding annual cycles of NDVI and comparing their behaviour for years associated with opposite NAO phases.Over the Iberian Peninsula there is strong evidence that positive (negative) values of winter NAO induce low (high) vegetation activity in the following spring and summer seasons. This feature is mainly associated with the impact of NAO on winter precipitation, together with the strong dependence of spring and summer NDVI on water availability during the previous winter. Northeastern Europe shows a different behaviour, with positive (negative) values of winter NAO inducing high (low) values of NDVI in spring, but low (high) values of NDVI in summer. This behaviour mainly results from the strong impact of NAO on winter temperature, associated with the critical dependence of vegetation growth on the combined effect of warm conditions and water availability during the winter season. Copyright © 2008 Royal Meteorological Society