Winter Temperatures Research Articles

Impact of climate change on the kelp Laminaria digitata – simulated Arctic winter warming

The Arctic is seasonally exposed to long periods of low temperatures and complete darkness. Consequently, perennial primary producers have to apply strategies to maximize energy efficiency. Global warming is occurring in the Arctic faster than the rest of the globe. The highest amplitude of temperature rise occurs during Polar Night. To determine the stress resistance of the ecosystem-engineering kelp Laminaria digitata against Arctic winter warming, non-meristematic discs of adult sporophytes from Porsangerfjorden (Finnmark, Norway) were kept in total darkness at 0°C and 5°C over a period of three months. Physiological variables, namely maximum quantum yield of photosynthesis (Fv/Fm) and dry weight, as well as underlying biochemical variables including pigments, storage carbohydrates, total carbon and total nitrogen were monitored throughout the experiment. Although all samples remained in generally good condition with Fv/Fm values above 0.6, L. digitata performed better at 0°C than at 5°C. Depletion of metabolic products resulted in a constant decrease of dry weight over time. A strong decrease in mannitol and laminarin was observed, with greater reductions at 5°C than at 0°C. However, the total carbon content did not change, indicating that the sporophytes were not suffering from “starvation stress” during the long period of darkness. A decline was also observed in the accessory pigments and the pool of xanthophyll cycle pigments, particularly at 5°C. Our results indicate that L. digitata has a more active metabolism, but a lower physiological and biochemical performance at higher temperatures in the Arctic winter. Obviously, L. digitata is well adapted to Arctic Polar Night conditions, regardless of having its distributional center at lower latitudes. Despite a reduced vitality at higher temperatures, a serious decline in Arctic populations of L. digitata due to winter warming is not expected for the near future.

Implications of temperature-dependent development and survival of Hemipteroseius adleri Costa, 1968 on its distribution in central Europe

Otopheidomenidae include 30 species of parasites of insects. These mites occur in areas with warm and hot climates. The only exception is Hemipteroseius adleri, the distribution of which reaches the central European region, which is characterised by a moderate climate with below-zero temperatures in winter. In Europe, H. adleri only parasitises the red firebug (Pyrrhocoris apterus). Field observations indicate that only fertilised females of H. adleri survive winter conditions. The aim of the study therefore was to evaluate the impact of air temperature on the development and survival of H. adleri. A research model was established involving mites parasitising red firebugs in laboratory conditions at 15, 20, 25 and 30 °C. After oviposition, no egg development was possible at 15 °C. Egg development began at 20 °C, however the egg-to-adult period lasted for 13 days and larval mortality was significantly higher at this temperature than at 25 and 30 °C. At the latter tem temperatures, mites matured fastest (five and four days, respectively). The net reproductive rate (R0) was 10.8, the mean generation time was (T) 14.4 (SD = 0.273), the intrinsic rate of population increase (rm) was 0.165 (SD = 0.003), and the finite rate of population increase (λ) was 1.12. At 25 °C, H. adleri required 4.2 days to double its population. The results indicate that the thermal conditions prevailing in early spring in central Europe are highly unfavourable for the effective reproduction of H. adleri. The presence of northern populations of this mite is discussed in the context of behavioural thermoregulation mechanisms adapted by its host, P. apterus.

Monitoring of thermal conditions and snow dynamics at periglacial block accumulations in a low mountain range in central Germany

AbstractThe Rhoen Mountains, a relict periglacial landscape in central Germany, feature a wide range of openwork block accumulations. Although located in a temperate climate, those have characteristics comparable with cold regions of higher altitude or latitude such as arctic‐alpine species, longer lasting snow patches or the discussed existence of summer or even year‐round ice lenses in one of the largest of these landforms in the Central German Uplands. This study aims for a characterization of the microclimatic conditions of two neighbouring block accumulations. Therefore, temperatures were registered by data loggers along profiles, and snow dynamics were monitored using time‐lapse cameras and terrestrial laser scans. These observations are finally compared with geophysical measurements to address the question of potential isolated low‐altitude permafrost occurrences. Mean ground surface temperatures show an inverse thermal gradient along the Schafstein block accumulation. Furrows were identified as the cold spots in winter, whereas snow melt holes are signs of a chimney effect. In summer, cold air flows out at ventilation holes along the front causing temperatures of up to 25°C below air temperatures, although no clear signs of permafrost were detected. Temperature correlations reveal periods indicative of a recurring internal summer air circulation. Coarse blocky substrate also favours ground cooling of the smaller Mathesberg block accumulation compared with its surroundings. Winter temperatures are influenced by a persistent snowbank forming due to drifting and blowing snow at the leeward edge of a plateau as little amounts of snow are sufficient to be redistributed by westerlies. The prolonged melt of the snowbank might have had or still has a local hydrological and geomorphological impact. Uncertainties remain regarding the behaviour of the microclimate of block accumulations in a warming climate. Being ‘cold spots’ of high ecological value further investigations are suggested.

Threshold Changes in Winter Temperature and Precipitation Drive Threshold Responses Across Nine Global Climate Zones and Associated Biomes

Globally, winter temperatures are rising, and snowpack is shrinking or disappearing entirely. Despite previous research and published literature reviews, it remains unknown whether biomes across the globe will cross important thresholds in winter temperature and precipitation that will lead to significant ecological changes. Here, we combine the widely used Köppen–Geiger climate classification system with worst-case-scenario projected changes in global monthly temperature and precipitation to illustrate how multiple climatic zones across Earth may experience shifting winter conditions by the end of this century. We then examine how these shifts may affect ecosystems within corresponding biomes. Our analysis demonstrates potential widespread losses of extreme cold (<−20°C) in Arctic, boreal, and cool temperate regions. We also show the possible disappearance of freezing temperatures (<0°C) and large decreases in snowfall in warm temperate and dryland areas. We identify important and potentially irreversible ecological changes associated with crossing these winter climate thresholds.

Energy-Saving Potential of Building-Integrated Photovoltaic Technology Applied to a Library in Changsha, China

With the increasing number of public buildings worldwide, their energy consumption has garnered significant attention. This study aims to promote building energy efficiency and emission reduction by exploring the application of Building-Integrated Photovoltaic technology in library retrofitting. Using a library in Changsha City as a case study, we conducted an energy consumption analysis of the building’s envelope and identified the window section as the highest energy consumer. We proposed a novel improvement scheme—the sun-shading photovoltaic panel (which shades the sun while generating electricity). Additionally, we utilized the roof space for the installation of conventional photovoltaic panels. Simultaneously, the primary objective of this paper was to derive a renovation strategy for public buildings in regions characterized by high summer temperatures and low winter temperatures based on the renovation case of this library. This paper comprehensively investigates the length and angle of sun-shading photovoltaic panels facing different directions, as well as the azimuth angle, tilt angle, and installation spacing of the conventional photovoltaic panels on the roof. Two retrofitting schemes were proposed. Through simulation and comparison, the second scheme was found to reduce the annual electricity consumption by 1,233,354 kWh, achieving a 35.4% decrease compared to the original building. Using the Changsha library as a template for public buildings, this study provided a retrofitting approach with Building-Integrated Photovoltaic technology via DesignBuilder, which could be extended to other geographic locations. The results demonstrated the significant energy-saving effects of the proposed retrofitting scheme.

Effect of Ocean Dynamic Processes on the Temporal-spatial Pattern of Persistent Organic Pollutants (PCB-153 and BDE-47) in the Shelf Seas

Field observations of persistent organic pollutants (POPs) in shelf seas presented abnormal phenomena such as high-concentration patches in offshore areas and different vertical profiles of POPs at the same location. We assumed that these phenomena were associated with the presence of bottom cold water mass (BCWM) in shelf seas and used a hydrodynamic-ecosystem-POP coupled model to confirm this hypothesis. Based on model results, with the formation of BCWM during summer, POPs accumulated inside BCWM due to their transport across the thermocline by the sorption to sinking particles. With the intensification of vertical mixing during winter, the release of POPs from BCWM induced high-concentration patches of POPs on the surface layer. Meanwhile, the low water temperature in winter was favorable for the gas deposition of POPs, which led to high surface concentrations of POPs. Because the accumulation of POPs in BCWM depended on the sorption of dissolved POPs by particles, not all types of POPs accumulated in BCWM. Some POPs even accumulated at the sea surface above the BCWM due to large gaseous deposition and weak sorption by particles. Using this feature, we proposed a prediction function for the accumulation of POPs in BCWM.

Intraseasonal relationship of winter temperatures in North America and warm sea surface temperatures in the Northeast Pacific

Winter temperatures in the North America (NA) exhibit evident intraseasonal variation, which has become more pronounced under global climate change. In particular, the wintertime relationship between NA temperatures and long-lasting positive sea surface temperature anomalies (SSTAs) in the Northeast Pacific (NEP), known as warm blobs, has been hotly debated in recent years. However, their relationship on intraseasonal timescales remains unclear. Using reanalysis data and an Atmospheric General Circulation Model, this study reveals that the intraseasonal variation of atmospheric circulation is the primary factor to induce intraseasonal temperature anomalies in NA after classifying warm SSTA events based on their different evolutions. Moreover, the atmospheric circulation anomalies over the mid-to-high-latitude regions are in part contributed by the feedback of NEP warm SSTAs to the atmosphere. Specifically, for early-winter warm SSTA events (peaking in November), there are two intraseasonal reversals in geopotential height anomalies over the NEP and NA, corresponding to a “cold-warm-cold” temperature change in NA. However, for mid-winter warm SSTA events (peaking in January), the atmospheric circulation pattern is relatively stable, mainly characterized by a “west high-east low” dipole, associated with persistent cold anomalies in NA. Then, the role of warm SSTAs over the NEP in the intraseasonal temperature variation is generally verified by the numerical simulations. Hence, although the NEP warm SSTAs may not be the dominant driver of the intraseasonal variations of winter NA temperatures, we emphasize the implication of their evolutionary differences in reflecting the NA temperature variations, which contributes to better predictability.

Predictability and applicability evaluation of winter temperatures in China based on Eurasian Arctic sea ice concentrations in autumn

Predictability and applicability evaluation of winter temperatures in China based on Eurasian Arctic sea ice concentrations in autumn

Seasonal forecasts have sufficient skill to inform some agricultural decisions.

Abstract Seasonal forecasts, which look several months into the future, are currently underutilized in active decision-making, particularly for agricultural and natural resource management. This underutilization can be attributed to the absence of forecasts for decision-relevant variables at the required spatiotemporal resolution and at the time when the decisions are made and a perception of poor skill by decision-makers. Addressing these constraints, we quantified the skill of seasonal forecasts in informing two agricultural decisions with differing decision timeframes and influencer variables: (a) whether to apply fertilizer in fall or wait until spring based on expected winter temperatures, and (b) drought response, such as whether to lease water based on expectations of drought. We also looked into how early the forecast can be provided without significant degradation in skill. Currently, drought response decisions are typically formulated in April, utilizing drought forecasts issued in the same month, while fall fertilization decisions are generally made between August and September. There is growing interest among stakeholders in the availability of earlier forecasts to inform these critical choices. We utilized the North American Multi-Model Ensemble (NMME) hindcasts for the time period 1982 - 2020 over the Pacific Northwest US to obtain meteorological variables. Runoff was estimated via simulations of the coupled crop-hydrology VIC-CropSyst model. The skill assessment with the Heidke Skill Score (HSS) yielded promising outcomes in both decisions for the entire Pacific Northwest region. Notably, NMME’s positive skill (median HSS of 30%) in predicting warmer winters identifies years when fertilizer application should be avoided to prevent fertilizer loss through mineralization (and associated costs). Similarly, there is skill in forecasting drought conditions in most irrigated watersheds for up to two months in advance of April, the current decision time. In conclusion, our findings affirm that contrary to the perception of low skill and resulting underutilization, current seasonal forecasts hold the potential to inform at least some key agricultural decisions.

Habitation conditions of the cave lion in the middle Indigirka River basin, North-East Siberia, during the Middle and Late Pleniglacial: Reconstruction based on palynological data

Pollen analyses of the sediment from skulls cavities of two cave lions Panthera spelaea from the middle Indigirka River basin, North-East Siberia, were performed to reconstruct the habitat conditions of the animals and to estimate changes in vegetation and climatic conditions in the region. Composition of the pollen and non-pollen palynomorphs indicates that the predators most likely died on the river floodplain or near the shore of the thermokarst lake, where grass/sedge meadows and shrub thickets, providing rich grazing grounds for large herbivores, existed. Palynological data indicate that both in the early Middle Pleniglacial and in the LGM the regional vegetation included forest, shrub tundra, meadow, mire and steppe communities similar to modern cold steppes in central Yakutia. During early Marine Isotope Stage (MIS) 3, the participation of arboreal vegetation was greater than in the Last Glacial Maximum (LGM) due to higher summer temperatures. In MIS 2, the role of open herbaceous cryoxerotic communities was greater, which is associated with a higher continentality of climate and a decrease in winter temperatures. This reconstruction is consistent with the general sequence of landscape and climatic changes in the Arctic and Subarctic regions of Siberia in the Middle and Late Pleniglacial, based on paleobotanical studies of the locations of mammoth fauna and multidisciplinary studies of the Late Pleniglacial sediments from a broader area.

Lessons learnt from a real-time attribution and contextualisation trial in a National Meteorological and Hydrological Service

Abstract When a record hot month occurs, timely and credible attribution and contextualisation information can enhance public understanding and future preparedness. This is particularly effective if provided in real time by a National Meteorological and Hydrological Service (NMHS). Many NMHSs are working to integrate research-based attribution methods into their operational services. In this study, researchers and climate service staff collaborated to assess the feasibility of delivering such information swiftly and aligned with standard NMHS data and procedures. The record warm July (winter) temperatures of Tasmania, Australia in 2023 were chosen to illustrate the trial. Rapid results were available three days after the event. Approximately half of the unusual warmth was attributed to climate change, with the likelihood of breaking the previous record at least 17 times higher in the current climate compared to a stationary pre-industrial climate (14% vs. 0.4%). The warming trend became evident in the 1980s, and by 2060, average July temperatures in Tasmania match the record temperature of July 2023 under a high emissions scenario. However, average July minimum temperatures were not well modelled, necessitating the addition of a higher-resolution forecast-based attribution method. In subsequent analysis, almost all the forecast temperature anomaly, and reduced storm activity, was attributable to climate change. Statistical analysis revealed that a weak El Niño partly offset the unusual warmth. To expedite these additional approaches, information drawn from real-time forecasts could be used. Lessons learnt from this trial include technical improvements to align better with NMHS protocols including using consistent datasets and baselines, and refining and automating the method suite. Logistical and communication enhancements included training staff to run the suite, improving communication materials, and developing delivery channels. These learnings provide key considerations for NMHSs as they move towards providing timely and credible climate attribution and contextualisation information as part of their operational services.

Shifts in geographic vulnerability of US corn crops under different climate change scenarios: corn flea beetle (Chaetocnema pulicaria) and Stewart’s Wilt (Pantoea stewartii) bacterium

Abstract Changing climate patterns will likely affect insect pressure on many agricultural crops. Mild winters may decrease the number of insects that experience reduced fecundity or that are killed during hard freezes. This may result in larger populations in subsequent years and allow for range expansion. Direct effects from pests are compounded by indirect effects, such as crop damage resulting from insect-vectored diseases. Corn flea beetle (Chaetocnema pulicaria) infestations have both direct and indirect effects on crops. This beetle is a pest on all types of corn in the United States, including sweet corn and grain corn (sometimes referred to as dent corn). It is responsible for damage to plant foliage and also serves as the primary overwintering vector for Pantoea stewartii bacterium, which causes Stewart’s Wilt, a disease that can severely impact the health and productivity of corn. Evidence suggests that warmer winters will contribute to a geographic range expansion for the corn flea beetle. Here we show the projected northward expansion of economically damaging crop losses caused by Stewart’s Wilt: (A) from 1980 to 2011, (B) projected by mid-century, and (C) projected by end-century. Our work suggests that climate change and associated increasing winter temperatures in the United States will lead to a dramatic increase in the probability of severe damage from corn flea beetle across the United States, including the Corn Belt. Predicted increases in pest and disease pressure will have negative ramifications for corn production and are likely to exacerbate issues associated with specific management tactics, such as pesticide application.

Renewable energy as an auxiliary to heat pumps: Performance evaluation of hybrid solar-geothermal-systems

The aim of this study is to combine renewable energy sources with heat pumps so that the usage of electricity needed to operate heat pumps is minimized along with associated fuel combustion. The aforementioned objective leads to reduce the energy consumption, the operational cost and the environmental impact of the heat pump. To minimize the usage of electricity, it is proposed that the heat pump (HP) system is combined by two renewable energy systems, a Solar Air Heater (SAH) and a Geothermal Well Water (G). To enrich this study, five prospective combinations of Heat Pump (HP), Solar Air Heater (SAH) placed Upstream (U) and Downstream (D) of the condenser, and Geothermal Water Well (G) were investigated. Hereafter, these five combinations are referred as HP-G, HP-S-U, HP-S-D, HP-G-S-U and HP-G-S-D. The thermal modeling of the aforementioned combinations in addition to baseline HP were developed and examined using an in-house computational code. To ensure that the input data used in the computational code are reliable, experiments were conducted to validate that the geothermal water temperature is higher than the ambient temperature in winter, in addition to confirming the analytical thermal modeling of the solar air heater. Numerical analyses and associated parametric studies revealed that the combination of Solar Air Heater (SAH) and a Geothermal Well Water (G) can efficiently increase the performance of the system by reducing the power needed to operate the compressor of HP. The gain in COP was found to be 48, 43, 81, 105 and 191 % for HP-G, HP-S-U, HP-S-D, HP-G-S-U and HP-G-S-D respectively. In addition, results revealed that the most efficient system is the (HP-G-S-D) for all simulated conditions and assumptions with a gain in COP that can reach up to 191 % in comparison to the baseline heat pump system.

Does the karst spring improve fish abiotic habitat in mountain streams?

Mountain streams constitute challenging habitat for many fish species due to rapid and variable flow, cool temperature, and limited food resources. Groundwaters recharge by karst spring may however mitigate harsh habit conditions of mountain streams providing niches for different fish species. This study aims to assess the suitability of mountain streams, replenished by karst springs, for various fish species like alpine bullhead, European grayling, brown and brook trout. The study was conducted in the Chochołowski Stream in the Western Tatra Mountains, Poland. The assessment of abiotic habitat is based on different characteristics of hydrological and thermal regimes as well as water chemical composition investigated between 01.09.2012 and 31.09.2014. The findings reveal that: 1) downstream variability of habitat abiotic conditions (such as water temperature, flow, water chemical composition) may affect the distribution of fish species, 2) karst springs contribute up to 100% of the stream’s recharge during periods of winter low flow, 3) karstic groundwater reduces the variability and amplitudes of stream water temperature and weaken the periodicity in water temperature associated with daily course of air temperature and solar radiation, 4) groundwaters prevent stream freezing in winter and moderate summer temperatures, 5) increasing mineralisation of water below the spring recharge may positively affect fish distribution. The findings underscore the importance of karst springs in modifying the abiotic conditions of fish habitat in mountain streams.

Optimized emamectin benzoate trunk injection: addressing temperature limitations for pine wilt disease control.

Pine wilt disease (PWD), caused by the pinewood nematode Bursaphelenchus xylophilus, poses a significant threat to global forestry, resulting in extensive economic and ecological damage. Traditional trunk injection agents (TIAs) are limited by environmental factors, such as high winter temperatures and vigorous resin flow, particularly in southern China. This study aimed to develop an ordinary temperature trunk injection agent (OTTIA) for year-round application and to evaluate its performance under high-temperature conditions in comparison to commercial TIAs. Extensive laboratory and field tests identified N,N-Dimethylformamide (DMF) and benzyl acetate as optimal solvents and Tween-40 as an effective emulsifier for the OTTIA formulation. The new agent was fully absorbed by Pinus massoniana within 3 h at temperatures exceeding 30 °C, outperforming existing commercial agents. Treated trees maintained comparable emamectin benzoate (EB) levels but achieved lower LC90 lethal concentration values (27.65 mg L-1), indicating greater efficacy. The OTTIA provided protection against PWD for ≤360 days postinjection. The development of OTTIA marks a significant advancement in PWD management, offering an effective solution for high-temperature regions and potentially transforming year-round treatment strategies. The results highlight the critical role of optimizing solvent and emulsifier combinations to enhance the efficacy and application of trunk injection agents, contributing to sustainable forest management and improved protection against PWD. © 2024 Society of Chemical Industry.

Drivers of summer Arctic sea-ice extent at interannual time scale in CMIP6 large ensembles revealed by information flow

Arctic sea-ice extent has strongly decreased since the beginning of satellite observations in the late 1970s. While several drivers are known to be implicated, their respective contribution is not fully understood. Here, we apply the Liang-Kleeman information flow method to five different large ensembles from the Coupled Model Intercomparison Project Phase 6 (CMIP6) over the 1970-2060 period to investigate the extent to which fluctuations in winter sea-ice volume, air temperature and ocean heat transport drive changes in subsequent summer Arctic sea-ice extent. This allows us to go beyond classical correlation analyses. Results show that air temperature is the most important controlling factor of summer sea-ice extent at interannual time scale, and that winter sea-ice volume and Atlantic Ocean heat transport play a secondary role. If we replace air temperature by net shortwave and downward longwave radiations, we find that the sum of influences from both radiations is almost similar to the air temperature influence, with the longwave radiation being dominant in driving changes in summer sea-ice extent. Finally, we find that the influence of air temperature is more prominent during periods of large sea-ice reduction and that this temperature influence has overall increased since 1970.

Linking housing, socio-demographic, environmental and mental health data at scale

Mental disorders are a growing problem worldwide, putting pressure on healthcare systems and wider society. Anxiety and depression are estimated to cost the global economy US$1 trillion per year, yet only 2% of global median government healthcare expenditure goes towards mental health. There is growing evidence linking housing, socio-economic status and local environmental conditions with mental health inequalities. The aim of this paper is to link several open-access datasets at the local area level (N = 32,844) for England to clinical mental health metrics and describe initial statistical findings. Two mental health metrics were used: Small Area Mental Health Index (SAMHI) and diagnosed depression prevalence. To demonstrate the utility of the longitudinal mental health data, changes in depression prevalence were investigated over two study periods (2011–19, i.e. austerity; and 2019–22, i.e. COVID-19). These data were linked to housing data (energy efficiency, floor area, year built, type and tenure) from Energy Performance Certificates (EPCs); socio-demographic data (age, sex, income and education deprivation, household size) from administrative records; and local environment data (winter temperature, air pollution and access to green space). The linked dataset provides a useful resource with which to investigate the social and environmental determinants of mental health. Practice relevance Initial observations of the data revealed a non-linear relationship between home energy efficiency (EPC band) and the mental health metrics, with depression prevalence higher in local areas where the mode EPC bands were C and D, compared with B and E. Researchers can further investigate this relationship using the dataset through robust statistical analysis, adjusting for confounding variables. National and local governments may use the dataset to help allocate resources to prevent and treat mental health conditions. Practitioners can map and interrogate the data to describe their local areas and make preliminary conclusions about the relationships between the built environment and mental health. This preliminary analysis of the data demonstrated a gradient in SAMHI and depression prevalence with income and employment deprivation at the local area level.

Effects of winter soil warming on crop biomass carbon loss from organic matter degradation

Global warming poses an unprecedented threat to agroecosystems. Although temperature increases are more pronounced during winter than in other seasons, the impact of winter warming on crop biomass carbon has not been elucidated. Here we integrate global observational data with a decade-long field experiment to uncover a significant negative correlation between winter soil temperature and crop biomass carbon. For every degree Celsius increase in winter soil temperature, straw and grain biomass carbon decreased by 6.6 ( ± 1.7) g kg-1 and 10.2 ( ± 2.3) g kg-1, respectively. This decline is primarily attributed to the loss of soil organic matter and micronutrients induced by warming. Ignoring the adverse effects of winter warming on crop biomass carbon could result in an overestimation of total food production by 4% to 19% under future warming scenarios. Our research highlights the critical need to incorporate winter warming into agricultural productivity models for more effective climate adaptation strategies.

Asymmetric winter warming reduces microbial carbon use efficiency and growth more than symmetric year-round warming in alpine soils

Asymmetric seasonal warming trends are evident across terrestrial ecosystems, with winter temperatures rising more than summer ones. Yet, the impact of such asymmetric seasonal warming on soil microbial carbon metabolism and growth remains poorly understood. Using 18O isotope labeling, we examined the effects of a decade-long experimental seasonal warming on microbial carbon use efficiency (CUE) and growth in alpine grassland ecosystems. Moreover, the quantitative stable isotope probing with 18O-H2O was employed to evaluate taxon-specific bacterial growth in these ecosystems. Results show that symmetric year-round warming decreased microbial growth rate by 31% and CUE by 22%. Asymmetric winter warming resulted in a further decrease in microbial growth rate of 27% and microbial CUE of 59% compared to symmetric year-round warming. Long-term warming increased microbial carbon limitations, especially under asymmetric winter warming. Long-term warming suppressed the growth rates of most bacterial genera, with asymmetric winter warming having a stronger inhibition on the growth rates of specific genera (e.g., Gp10, Actinomarinicola, Bosea, Acidibacter, and Gemmata) compared to symmetric year-round warming. Bacterial growth was phylogenetically conserved, but this conservation diminished under warming conditions, primarily due to shifts in bacterial physiological states rather than the number of bacterial species and community composition. Overall, long-term warming escalated microbial carbon limitations, decreased microbial growth and CUE, with asymmetric winter warming having a more pronounced effect. Understanding these impacts is crucial for predicting soil carbon cycling as global warming progresses.

Alternative products for breaking dormancy in ‘Reubennel’ plum in subtropical regions

Abstract Plum is a temperate fruit tree and thus shows abundant vegetative bud percentage and flowering following extended periods of low winter temperatures. When adequate periods of low temperatures do not occur, it is necessary to apply products to stimulate bud dormancy break and uniform leaf and flower appearance. This application is more frequently needed when plum trees are grown in the tropics. The objective of this study was to evaluate alternative products for breaking dormancy in ‘Reubennel’ plum in subtropical regions. The experiment was conducted at a site located at 22°22’S, 43°77’W and 1,173 m altitude, with a Cwa climate type. The following treatments were applied to eight-year-old ‘Reubennel’ plum trees in the 2018 and 2019 production cycles: 1) a negative standard composed of only water (control), a positive standard composed of 2) 1.5% hydrogen cyanamide (HC) (Dormex® commercial product) plus 4.5% mineral oil, 3) Erger G® organomineral fertilizer supplemented with 3% calcium nitrate, 4) 5% potassium nitrate and 5) 0.3% copper sulfate. Two liters of the treatment solutions were applied per plant with a sprayer. The effect of the tested products on vegetative bud percentage and flowering capacity, production cycle reduction and production and quality of ‘Reubennel’ plums was evaluated. It was concluded that the chemicals used to break dormancy affected only the phenology of plum trees in this subtropical region and that the application of copper sulfate can be used to break dormancy in these trees.