Seasonal Relationships Research Articles

Relationship of Season and Cuttings’ Diameter with Rooting Ability of Culm-Branch Cuttings in Bambusa tulda and Bambusa nutans

Relationship of Season and Cuttings’ Diameter with Rooting Ability of Culm-Branch Cuttings in Bambusa tulda and Bambusa nutans

English

BACKGROUND Previous studies have reported seasonal variations in peptic ulcer disease (PUD), but only few large-scale, population-based studies have been conducted in this regard. In this study, we wanted to present the seasonal relationship of peptic ulcer perforation admissions, seasonal variation of its incidence, modes of surgical management, the seasonal distribution of postoperative severe complications and the patient outcome. METHODS This is a retrospective cohort study. Patients hospitalized for peptic ulcer perforation between 1st January 2008 and 1st January 2020 were included in the study. The patients were divided into two groups according to postoperative complication status as Group1 - Clavien Dindo < 3 and Group 2 - Clavien Dindo > 3. Age, gender and seasonal periods were compared. In addition, patients were divided into three groups according to age as 18 – 40 yrs., 40 - 60 yrs. and over 60 yrs. The gender and complication status of the patients were also evaluated in seasonal groups. RESULTS 135 patients participated in our study. Group 1 constituted of 107 patients and Group 2 constituted of 28 patients. Admission to the hospital due to peptic ulcer perforation was most common in spring (29.6 %) and summer (29.6 %). Twenty - eight patients had Clavien - Dindo 3 or more complications. The mean age was higher in Group 2 (70.78 vs 50.2 P : 0.001) as well as female gender dominancy (60.7 % vs 29.9 %). In Group 2 winter months were more frequent (46,5 % vs 21.5 %); however, there was no significant difference between the seasons and the complication groups. In Group 2, female gender was more common in winter (21.7 % vs 69.2 % P:0.005) and autumn season (31.3 % vs 100 % P : 0.027). CONCLUSIONS In our study, we found an increased incidence of peptic ulcer perforation in spring and summer. For patients at higher risk, an appropriate pharmacological treatment can be arranged to reduce the risk of perforation during the risky season. KEY WORDS Peptic Ulcer Disease, Seasonal Change, Complication

Seasonal influence of water quality on the assemblage and diversity of phytoplankton along Dubai Creek, Arabian Gulf

The research aims to find out the seasonal variation in phytoplankton diversity, composition and their abundance in response to various environment parameters. Seasonal variation in the phytoplankton community associated with various biological and water quality parameters (Temperature, Salinity, Dissolved Oxygen (DO), Nitrate (NO3-N), Phosphate (PO4-P), Chlorophyll-a, Phaeophytin and Carotenoids) were studied along 10 sampling stations of the Dubai Creek during January–December 2018. One-way ANOVA (p< 0.005) and correlation coefficient between the phytoplankton abundance and the physico-chemical parameters revealed positive trends of phytoplankton composition. The phytoplankton species diversity varied from 55 (Sanctuary) to 95 (Creek mouth). A total of 110 species of phytoplankton were recorded in Dubai Creek, comprising of 76, 29, 3, 1 and 1 species of Bacillariophyceae, Dinophyceae, Cyanophyceae, Euglenophyceae and Ciliophora respectively. The annual mean variation in phytoplankton population were recorded between 744 (Hyatt Regency) to 31906 cells × 103 L−1 (STP outfall). Due to the morphology, hydrodynamic regime and polluted nature in the upper Creek presented an unique phenomenon where the phytoplankton species and density divided Dubai Creek into two (2) sections. The first section (downstream of the Dubai Creek) include the stretch from the Creek mouth to the Floating bridge stations with low population and high species diversity, whereas the other section (upstream of the Dubai Creek) cover stations from Al Gharhoud bridge up to the Sanctuary with dense population and low species diversity. The diversity index showed highest along downstream of Dubai Creek. A ‘k’ dominance plots for phytoplankton abundance between samples showed lower and higher steep curves along downstream (Creek mouth, Abra and Hyatt Regency) and upstream regions (Al Jaddaf, Sanctuary and STP outfall) of Dubai Creek. This could probably de due to the polluted and unpolluted conditions of the Creek. Bray–Curtis cluster analysis showed strong similarity (>60%) among upstream stations of Dubai Creek associated with polluted conditions, whereas an overlap of Creek mouth, Abra and Hyatt Regency on remaining stations showed unpolluted and healthy conditions of the phytoplankton in downstream stations. Canonical Correspondence Analysis revealed that Bacillariophyceae have a positive strong relationship with different environment variables between stations Abra, Hyatt Regency and Creek mouth, indicating influence of high flushing of the coastal waters on phytoplankton species and diversity. The study presents an outline of the seasonal dynamic relationship between phytoplankton structure and environmental conditions in the Dubai Creek.

Variability of SST and ILD in the Arabian Sea and Sea of Oman in Association with the Monsoon Cycle

Sea surface temperature (SST) and isothermal layer depth (ILD) are important oceanic parameters and could play a significant role in understanding the upper thermal structure as well as improve the predictive capability of monsoons in the tropical oceans. In a disparate departure from the past research, the present study investigates the seasonal variability of SST and ILD in association with the monsoon cycle in the Arabian Sea and Sea of Oman regions by examination of Argo datasets for 2016-17. In this study, the ILD climatology is determined from temperature profiles provided by the Argo floats based on a threshold technique T z ≥ SST − 1 ° C to investigate the region of stronger and weaker monsoon wind forcing. For SST, values of temperature are used nearest to the sea surface (depth z ≤ 5 m). The region is split into four distinct zones for an accurate description of the monsoon cycle: the south Arabian Sea, the central Arabian Sea, the north Arabian Sea, and the Sea of Oman. It is observed that summer monsoon is more pronounced in the south-central basin of the Arabian Sea, where ILD is deepening (&gt;100 m in September 2016) mainly due to stronger wind forcing in this region. On the contrary, the Sea of Oman region is displayed with smaller ILD amplitude (&lt;10 m in June 2016) with larger SST, meaning that this region is weakly influenced by the summer monsoon. The seasonal relationship established between ILD variability and monsoon cycle for 2016-17 shows that ILD could be a useful indicator for predicting summer monsoon in the Arabian Sea regions. Our analysis results indicate that the dynamics for SST variability are different in these regions and are influenced either by large-scale atmospheric forcing, such as the El Niño-Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD), or by the effects of mesoscale variations occurring along the Oman-Arabian coast.

Ringed Seal Diet and Body Condition in the Amundsen Gulf region, Eastern Beaufort Sea

Diet from stomach contents and body condition from morphometric measurements were obtained for 169 (108 stomachs analysed) ringed seals (Pusa hispida) for the Amundsen Gulf region in the western Canadian Arctic from 2015 to 2018. Sampling was from subsistence-harvested seals from the three communities of Paulatuk (spring, summer, and autumn), Sachs Harbour (summer), and Ulukhaktok (winter), Northwest Territories. Stomach contents were separated through sieves and by hand, and taxa identified to the lowest taxonomic level possible and weighed. Stomachs were fullest (by weight and prey count) in the autumn, which suggests that foraging was most intense and successful at that time. A total of 93 prey taxa, including 17 fish and 76 invertebrate species were identified. Several fish and invertebrate species were regularly found together, the most common being Arctic cod (Boreogadus saida), sand lance (Ammodytes hexapterus), capelin (Mallotus villosus), and hyperiid amphipods (Themisto spp.). Condition measurements inferred from blubber thickness, although showing considerable variation among sites and years, had a seasonal relationship with maximal depth during the autumn and winter. Overall, the diet of ringed seals in Amundsen Gulf was broadly similar to those reported from other areas while also indicating some degree of regional specificity. When compared to the diet of ringed seals in the same area in the 1980s, the results presented here were more diverse, with new or increased numbers of subarctic species (e.g., saffron cod, Eleginus gracilis) found in the samples. This finding is a likely consequence of climate warming, as increasing numbers of subarctic species move north with warming ocean temperatures in the Arctic.

Investigating the spatiotemporal non-stationary relationships between urban spatial form and land surface temperature: A case study of Wuhan, China

This article aims to examine the pathways of urban spatial forms in mitigating urban heat island (UHI) intensity across urban areas in different seasons. By investigating the case of Wuhan, we quantified urban spatial form (USF) factors concerning land use, land cover, and building-group morphology and the land surface temperatures (LST) in summer, autumn and winter of 2,357 block units. The seasonal relationships between USF and LST are explored at the large scale of the whole study area and different zones of block units categorized by floor area ratio. The results suggest that relationships between USF and LST vary spatially and temporally. First, although most urban spatial form factors show significant correlations on LST at the global scale, the correlations vary significantly among low, medium, and high floor-area-ratio zones. Second, USFs largely contribute to the variance of LST in summer and autumn compared with winter. Third, building morphology exerts more impact on LST in relatively highly intensive built-up zones, while land use and land cover factors have more impact in low-intensity areas. Lastly, UHI can be precisely mitigated by optimizing USFs considering the varied relationships between USFs and LST. This study theoretically deepens the understanding of the variation of the relationships between built-up urban areas and UHI at the scale of the basic planning regulation units, which is conducive to formulating down-to-earth regulation measures to cool cities and communities.

Seasonal Associations Between Foodborne Campylobacter Infections and Ambient Temperature in US, 2010–2019

Abstract Objectives In order to effectively mitigate the effects of climate change on human health, spatiotemporal relationships between Campylobacter infections and environmental drivers have to be systematically examined to determine whether common seasonal summer peaks observed in Campylobacter infections are well aligned with peaks in raising ambient temperatures. This study aims to evaluate the seasonal relationship between monthly ambient temperature and the monthly Campylobacter infections routinely collected by the CDC Foodborne Diseases Active Surveillance Network (FoodNet) in the United States in 2010–2019. Methods We created time series of monthly Campylobacter infection rates from the FoodNet Fast platform for ten participating states from January 2010 to December 2019 (120 months). We estimated average monthly temperatures for the ten states for the study period using the National Climate and Data Center's Global Summary of the Day database. To assess the seasonal synchronization and determine the lag effect, we used serial cross-correlation analysis. To examine the associations between Campylobacter rates with ambient temperature and adjust for seasonality and trend, we applied a harmonic negative binomial mixed-effects regression model. We also estimated peak timing and amplitude for infections and temperature using the δ-method. Results Serial synchronization between monthly Campylobacter infection rates and ambient temperature was observed in all FoodNet Surveillance states except for California. A one-month delay in peak infection after the peak in temperature was detected in Colorado, Connecticut, Maryland, Minnesota, New Mexico, New York, and Oregon. After adjusting for seasonality and trend across ten states, the relative risk of infection rates increased by 5% with the increase in monthly average temperature by 5.45°C equivalent to a shift from 75th to 95th percentile (95%CI: 1.02–1.09, p &amp;lt; 0.002). Conclusions An increase in monthly average temperature is associated with an increased risk of Campylobacter infection after adjusting for common summer seasonal patterns. Knowledge of the relationship will potentially improve the reliability and accuracy of integrated early warning outbreak forecasts and could guide climate mitigation strategies. Funding Sources None.

Seasonal dynamics in fish distribution and abundance revealed by an acoustic survey in coastal waters of the Suzu Area, Kochi Prefecture, Japan

For Japan's fishery, it is essential to conduct sustainable and efficient fishery owing to the decline in fish catch as well as the fisher population. To obtain information that contributes to sustainable and efficient fishery, we researched appropriate set-net locations with regard to fish distribution, abundance, and environmental characteristics. We conducted surveys from 2017/5 to 2018/2 in the Suzu coastal area, Kochi Prefecture, where the only main industry is set-net fishery. We investigated the seasonal relationships between fish school characteristics, including distribution and size, and marine environmental conditions in the Suzu coastal area, using a quantitative echo sounder (KSE300 SONIC, 38 kHz) and other devices. We observed that every season showed similar trends in the horizontal structure; fish densities were higher on the coast side, and in some seasons, these were higher at approximately 2000 m offshore. In addition, fish densities were higher in seas at depths up to 30 m. Set-net fishery is conducted in Suzu District at 300 m from the shoreand at a depth of approximately 35 m. The point of installation of set-nets is based on fish school distribution. In our study, we determined the most appropriate set-net installation points. This study not only provides a scientific basis for point selection but could also enhance the existing fishery that is limited to an aging fisher population and catch instability.

Potential Human and Plant Pathogenic Species in Airborne PM10 Samples and Relationships with Chemical Components and Meteorological Parameters

A preliminary local database of potential (opportunistic) airborne human and plant pathogenic and non-pathogenic species detected in PM10 samples collected in winter and spring is provided, in addition to their seasonal dependence and relationships with meteorological parameters and PM10 chemical species. The PM10 samples, collected at a Central Mediterranean coastal site, were analyzed by the 16S rRNA gene metabarcoding approach, and Spearman correlation coefficients and redundancy discriminant analysis tri-plots were used to investigate the main relationships. The screening of 1187 detected species allowed for the detection of 76 and 27 potential (opportunistic) human and plant pathogens, respectively. The bacterial structure of both pathogenic and non-pathogenic species varied from winter to spring and, consequently, the inter-species relationships among potential human pathogens, plant pathogens, and non-pathogenic species varied from winter to spring. Few non-pathogenic species and even fewer potential human pathogens were significantly correlated with meteorological parameters, according to the Spearman correlation coefficients. Conversely, several potential plant pathogens were strongly and positively correlated with temperature and wind speed and direction both in winter and in spring. The number of strong relationships between presumptive (human and plant) pathogens and non-pathogens, and meteorological parameters slightly increased from winter to spring. The sample chemical composition also varied from winter to spring. Some potential human and plant pathogens were correlated with chemicals mainly associated with marine aerosol and/or with soil dust, likely because terrestrial and aquatic environments were the main habitats of the detected bacterial species. The carrier role on the species seasonal variability was also investigated.

Seasonal Relationships Between Diatom Assemblages and Environmental Conditions Vary Between Epipelic- and Epipsammic-dominated Tidal Flat Diatom Communities in the Yaquina Estuary, Oregon, USA

This research examined temporal and spatial patterns of microphytobenthos (MPB) and relationships with environmental variables in a Pacific Northwest, USA estuary with complex environmental gradients. Sediment composition, salinity, and nutrients varied between sites closer to the estuary mouth (MAR), and those further upstream (RIV) and seasonal patterns in these variables also differed between MAR and RIV sites. Average MPB biomass was 57.8 ± 22.9 μg chlorophyll cm−3 at MAR sites and 29.9 ± 13.3 μg chlorophyll cm−3 at RIV sites. Relationships between MPB biomass and environmental conditions depended on season. The MPB diatom assemblage was influenced primarily by location within the estuary and secondarily by season. Epipsammic taxa, including Catenula adhaerens, Planothidium delicatulum, and Opephora spp. 1, were most abundant at MAR sites, while highly motile taxa in the genera Navicula senso lato and Nitzschia were abundant at RIV sites. Seasonal shifts in diatom community structure were evident at RIV sites and were driven primarily by changes in dominant epipelic taxa. Relationships between the MPB diatom assemblage and environmental conditions varied between MAR and RIV sites. Physical variables, including distance from the estuary mouth, sediment composition, land use in the 100 m buffer, and to a lesser extent, salinity, were correlated to the MAR assemblage. In contrast for RIV sites, salinity and nutrients were correlated to the diatom assemblage. Despite the complexity inherent in elucidating diatom–environmental relationships, our results suggest that tidal flat diatoms can be used to assess the environmental conditions of estuaries.

Seasonal Precipitation and Soil Moisture Relationships Across Forests and Woodlands in the Southwestern United States

AbstractPrecipitation [P: mm] controls forest and woodland dynamics in the southwestern United States (SWUS) by altering soil moisture [θ: mm3 mm−3] availability, but the influence of P on θ is complex, varying across space and time. We evaluated seasonal P and θ relationships at shallow (0–20 cm) and intermediate (50 cm) soil depths for nine semiarid forest and woodland sites (56 total years), which comprised three elevation gradients in the SWUS. We developed time‐varying definitions of winter (snow accumulation), spring (moisture recharge), and summer (moisture deficit), and determined how these sites exhibited similar P influence on θ across depths in the soil profile, between seasons, and in seasons with above‐ and below‐average P. Higher elevation sites (&gt;2,800 m) experienced greater winter P, longer springs, and shorter summers compared to lower elevation sites (&lt;2,500 m). Seasons with above‐ and below‐average P reduced elevation‐associated differences. θ at 0–20 cm was generally decoupled from θ at 50 cm in seasons with average and below‐average P, imparted by differences in spring and summer rainfall versus winter snowfall. Notably, across‐season influence of θ (e.g., a season’s similarity to subsequent seasons) was high when the first season experienced above‐ or below‐average P, and the subsequent season experienced average P, illustrating an important temporal connection initiated by wet and dry conditions. These results illustrate similarities in P‐θ relationships across widely differing ecosystems in the SWUS, and elucidate how these relationships may be altered in a changing climate.

Can Land Surface Models Capture the Observed Soil Moisture Control of Water and Carbon Fluxes in Temperate‐To‐Boreal Forests?

AbstractThe reservoir of soil water is exchanged with the atmosphere through evaporative processes, which are mediated via vegetation through transpiration. Carbon uptake is closely coupled to transpiration, and most process‐based models link transpiration and photosynthesis explicitly. Here, we evaluate the simulation of water and carbon fluxes in forested areas of North America using point‐based simulations of the Community Land Model version 5 (CLM5) with Soil Moisture Active/Passive (SMAP) satellite derived soil moisture measurements and in situ measurements at eight Fluxnet and two United States Climate Research Network (CRN) sites. Compared to observations, there is a broad site‐to‐site variability in simulated soil moisture, with some sites exhibiting wet biases and others dry biases. The bias sign does not depend on ecosystem or other environmental drivers such as radiation and temperature. Compared to Fluxnet latent heat (LH) and gross primary production (GPP) flux tower observations, simulated LH flux biases at deciduous broadleaf forests are linked with soil moisture biases, and the model captures the observed seasonal cycle and parabolic seasonal relationship with soil moisture. The parabolic shape is driven by high soil moisture and low LH fluxes in June, peak LH and drier soil conditions in July, followed by further soil moisture drawdown in August. GPP is underestimated at most sites, and the model exhibits a linear relationship between soil moisture and GPP. Because the photosynthesis parameterizations are similar in most Earth system models, further model development that incorporates observations and observed relationships is needed to accurately capture the GPP‐soil moisture relationship.

Relationship of extreme precipitation, surface air temperature, and dew point temperature across the Tibetan Plateau

Global warming is expected to have profound socio-economic and environmental consequences, and one of the key concerns is extreme precipitation. The classic theory indicates that the variation of extreme precipitation will follow the thermodynamically based Clausius-Clapeyron relation (increasing at a rate of approximately 7%/°C). However, the interaction and the seasonal variation of the relationship between extreme precipitation and temperature has not been thoroughly integrated. Here, we use quantile regression and the binning method to process meteorological station data and the reanalysis data from 78 stations on the Tibetan Plateau (TP), and estimate the sensitivity and dependency of extreme precipitation to both surface air temperature and dew point temperature. The results indicate that the majority of the meteorological stations experience a positive scaling between extreme precipitation and surface air temperature, with the median of surface air temperature scaling close to 2.5%/°C. With regard to scaling during individual seasons, 80% of stations possess negative scaling of the 99th percentile of extreme precipitation with temperature in summer, while 63 stations (81% of the total) display positive trends in winter, and the other 19% have negative scaling. A stronger scaling (3.5%/°C) occurs between dewpoint temperature and extreme precipitation. For surface air temperature 8 °C, relative humidity decreases with increasing temperature and dewpoint depression increases, so dewpoint temperature increases more slowly than temperature, resulting in the stronger scaling relationship with dewpoint temperature. The depression of dewpoint temperature presents a slight decrease in −3–8 °C interval, but dewpoint temperature increases faster than other intervals, and the scaling relationship of dewpoint temperature is consistently larger than with surface air temperature due to the small increasing rate with dewpoint temperature and increasing extreme precipitation intensity. Our results emphasize that the increasing temperature has clear scaling and seasonal relationship with extreme precipitation on the TP, and the atmospheric humidity variation has an effect on the overall difference in the scaling relationships of extreme precipitation with surface air temperature and dewpoint temperature. The variations of seasonality and the effects of atmospheric humidity for extreme precipitation should also be carefully considered in future research.

Monitoring socio-climatic interactions to prioritise drinking water interventions in rural Africa

Rainfall variability and socioeconomic shocks pose a revenue risk for drinking water services in rural Africa. We examine the year-on-year and seasonal relationship between rainfall and remotely monitored water usage from rural piped schemes in four sub-Saharan countries to identify patterns that warn of a threat to operational sustainability. Continuous monitoring of socio-climatic interactions can reveal distributions and magnitudes of risk and guide policy action to safeguard rural water services.

Hygienic aspects of using the resources of small rivers of the Volga region for drinking water supply on the example of the Saratov region

The transformations in the environment occur both under the influence of natural processes and anthropogenic influences. Small rivers are one of the most vulnerable to changes in natural objects. Wastewater is a specific source of pollution for reservoirs: the most frequent pollution of small rivers is caused by flushing from agricultural land. The lower Volga region belongs to regions with unfavorable conditions for water supply, which is caused by a complex of natural and anthropogenic factors. The Saratov region by its geographical location, climate conditions, level of development of socio-economic relations, features of agricultural production largely reflects the regional characteristics of the Lower Volga region and can serve as a model for making management decisions to improve the hygienic conditions of water supply in rural areas of this region. Analysis of the results of laboratory studies, as well as sanitary and topographical study of the coastal zone indicates insufficient implementation of water protection measures on the researched rivers: they are mainly cosmetic in nature and do not contribute to a radical improvement of the sanitary and ecological situation on small rivers. Given the excess of water quality indicators in the flood period, also in the summer, the water of the Nahoy and B. Karaman rivers can be attributed to the second class of water supply sources, which implies the need to clean and disinfect water from these reservoirs when using it for drinking purposes. Values of the total hazard index for small rivers showed a clear seasonal relationship: for samples taken in the summer, they were higher than for samples taken in the spring. The value of non-carcinogenic risk exceeded the acceptable value for all samples, while the greatest contribution to the probability value of risk is made by nitrites, nitrates, iron and manganese, as typical surface water pollutants of arid zone water.

Microbial diversity characteristics and the influence of environmental factors in a large drinking-water source

Although the influence of environmental factors on the microbial community in water sources is crucial, it is seldom evaluated. The seasonal relationship between microbial diversity of bacteria and fungi and environmental factors was investigated in a large drinking-water reservoir using Illumina MiSeq sequencing. Forty-one bacterial phyla and nine fungal phyla were analyzed in the Qingcaosha Reservoir, Shanghai, China. The predominant bacterial phyla were Actinobacteria, Proteobacteria, Bacteroidetes, and Cyanobacteria, with the maximum relative abundance of 46%, 36.6%, 16.1%, and 14.9%, respectively. Actinobacteria were observed to be the predominant bacterial phylum during spring and summer. The maximum relative abundance of unclassified fungi appeared in summer (98.8%), which was higher than that of Ascomycota and Basidiomycota (11.7% and 8.2%, respectively). Principal coordinate analysis (PCoA) results showed that the structural similarity in the bacterial community was greater during summer and winter; however, the fungal community exhibited a greater similarity during spring and summer. 2-Methylisoborneol (2-MIB), an olfactory compound produced by microorganisms, was detected at a concentration of 8.97 ng/L during summer, which was slightly lower than the olfactory threshold (10 ng/L). The positive correlation between Actinobacteria and unclassified fungi and 2-MIB (p < 0.05) confirmed that Actinobacteria and unclassified fungi produced 2-MIB. The chemical oxygen demand (COD) was 1.48–1.94 mg/L, and the maximum concentrations of total nitrogen (TN) and total phosphorus (TP) were 2.1 mg/L and 0.5 mg/L, respectively. Chloroflexi were negatively correlated with COD (p < 0.05) but positively correlated with TP (p < 0.01). Nitrospirae were negatively correlated with COD (p < 0.05), but positively correlated with TN (p < 0.05). Among the classified fungi, Rozellomycota, Basidiomycota (p < 0.05), and Chytridiomycota (p < 0.01) were positively correlated with TP. Therefore, the relative abundance of predominant bacteria was affected by various environmental factors; however, fungi were mainly influenced by TP.

Seasonality in soil temperature may drive the seasonal dynamics of carbonate‐derived CO2 efflux in a calcareous soil

AbstractCarbonates in soils may act as a potential source of CO2 efflux from calcareous soils to the atmosphere. However, its seasonal dynamics and relationships with soil temperature or soil moisture are not well‐understood. A 5‐yr warming experiment was performed to evaluate the effects of symmetric (all season) and asymmetric (seasonal) warming on soil organic fraction (SOC)‐derived efflux and carbonate‐derived CO2 efflux (partitioned by δ13C signature) from a calcareous soil in the karst region of southwest China. In region where precipitation mostly falls during summer, an average of 2.0°C warming under both symmetric and asymmetric warming scenarios produced 6–34% and 11–14% increases in the SOC‐derived efflux and carbonate‐derived efflux, respectively. The SOC‐derived efflux in the symmetric warming scenario was 1.6 times that of the asymmetric warming scenarios, but no changes were found for the carbonate‐derived efflux. The SOC‐derived efflux was positively correlated with both soil temperature and soil moisture, suggesting an entailment with biotic processes. In contrast, the carbonate‐derived efflux was positively correlated with soil temperature, but was poorly correlated with soil moisture. Thus, the seasonal dynamics of the carbonate‐derived efflux in calcareous soils were likely driven by abiotic processes.

242. Seasonality in antibiotic use and resistance across multiple bacterial pathogens and antibiotic classes

BackgroundAntibiotic use is an important driver of antibiotic resistance. Previous studies have shown that this relationship is detectable on a seasonal timescale, where seasonally cycling antibiotic prescribing corresponds with cycling levels of resistance. Here, we evaluated the seasonal relationship between antibiotic use and resistance across multiple species and antibiotic classes in Boston, Massachusetts.MethodsTo conduct our study, we analyzed antibiotic claims data from the Massachusetts All Payers Claims Database for five antibiotic classes, beta-lactams, macrolides, quinolones, tetracyclines, and nitrofurans, which together account for 74% of the total outpatient antibiotic claims in this dataset. In addition, we analyzed antibiotic susceptibility data for clinical isolates collected from two tertiary care hospitals, focusing on three clinically important bacterial pathogens. Our analysis included a total of 131,815 Escherichia coli, 47,208 Staphylococcus aureus, and 27,237 Klebsiella pneumoniae isolates collected over the years 2007–2019, with susceptibility testing data for 5–6 antibiotics per species. To determine the extent of seasonality in use and resistance, we fit the antibiotic claims data for each antibiotic class and the minimum inhibitory concentration (MIC) data for each species-antibiotic combination to a sinusoidal model with either a 6 or 12-month period.ResultsWe found that use of all 5 antibiotic classes and resistance in 9 out of 15 species-antibiotic combinations showed a significant amplitude of seasonality (p-value < 0.05). Despite different seasonal peaks in antibiotic use across classes, resistance peaked in the winter for almost all species-antibiotic combinations and was most highly correlated with use of winter-peaking antibiotic classes, beta-lactams and macrolides.ConclusionOverall, these results suggest that co-resistance and “bystander” selection – selection for resistance in asymptomatically colonizing and potentially pathogenic bacteria that are not the direct target of treatment – mediate the effects of antibiotic prescribing on the landscape of resistance.Disclosures All Authors: No reported disclosures

Long‐Term Trends for Marine Sulfur Aerosol in the Alaskan Arctic and Relationships With Temperature

AbstractMarine aerosol plays a vital role in cloud‐aerosol interactions during summer in the Arctic. The recent rise in temperature and decrease in sea ice extent have the potential to impact marine biogenic sources. Compounds like methanesulfonic acid (MSA) and non‐sea‐salt sulfate (nss‐SO42−), oxidation products of dimethyl sulfide (DMS) emitted by marine primary producers, are likely to increase in concentration. Long‐term studies are vital to understand these changes in marine sulfur aerosol and potential interactions with Arctic climate. Samples were collected over three summers at two coastal sites on the North Slope of Alaska (Utqiaġvik and Oliktok Point). MSA concentrations followed previously reported seasonal trends, with evidence of high marine primary productivity influencing both sites. When added to an additional data set collected at Utqiaġvik, an increase in MSA concentration of + 2.5% per year and an increase in nss‐SO42− of + 2.1% per year are observed for the summer season over the 20‐year record (1998–2017). This study identifies ambient air temperature as a strong factor for MSA, likely related to a combination of interrelated factors including warmer sea surface temperature, reduced sea ice, and temperature‐dependent chemical reactions. Analysis of individual particles at Oliktok Point, within the North Slope of Alaska oil fields, showed evidence of condensation of MSA onto anthropogenic particles, highlighting the connection between marine and oil field emissions and secondary organic aerosol. This study shows the continued importance of understanding MSA in the Arctic while highlighting the need for further research into its seasonal relationship with organic carbon.

Prevalence of vitamin d deficiency in hospital admission for hip fracture: prevalence and its seasonal relationship

Prevalence of vitamin d deficiency in hospital admission for hip fracture: prevalence and its seasonal relationship