Seasonal Variation Research Articles

Uncovering sources, distribution, and seasonal patterns of trace element deposition: the elemental puzzle of the western Himalayas.

The transport and deposition of atmospheric pollutants in the Himalayas have a adverse impact on the climate, cryosphere, ecosystem, and monsoon patterns. Unfortunately, there is a insufficiency of data on trace element concentrations and behaviors in the high-altitude Himalayan region, leading to limited research in this area. This study presents a comprehensive and detailed comprehension of trace element deposition, its spatial distribution, seasonal variations, and anthropogenic signals in the high-altitude Kashmir region of the Western Himalayas. Our investigation involved the analysis of 10 trace elements (Al, Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, and Pb) in glacier ice, snow pits, surface snow, and rainwater collected at various sites including Kolahoi, Thajwas, Pahalgam (Greater Himalayan ranges), and Kongdori and Shopian (Pir Panjal Ranges) during 2021.The study reveals distinct ranges of concentrations for the trace elements at different sampling sites. Our analysis of trace element concentration depth profiles in snow pits reveals seasonal fluctuations during the deposition year. The highest concentrations were found in the autumn(below 20cm) and summer (top layer), compared to the winter concentration (10-20cm). The high enrichment factors (EFs) suggest the severity of human-induced trace metal deposition in the western Himalayan region, relative to surrounding regions. Surprisingly, the concentrations and EFs of trace elements showed seasonal contradictions, with lower concentration values and higher EFs during the non-monsoon season and vice versa. A source apportionment analysis using the positive matrix factorization (PMF) technique identified five sources of trace element deposition in the region, including crustal sources (32.33%), coal combustion (15.62%), biomass burning (17.63%), traffic emission (18.8%), and industrial sources (15.6%). Additionally, the study incorporated backward trajectories coupled with δ18O using the NOAA HYSPLIT model to estimate moisture sources in the region, which suggests atmospheric pollutants predominately deposited from the large-scale atmospheric circulation from westerlies (75%) during non-monsoon season. These findings underscore the urgent need for enhanced monitoring and research efforts in the future.

Application of multiplatform remote sensing data over East Asia Ocean: aerosol characteristics and aerosol types.

It is important to explore the characteristics and rules of atmospheric aerosol in the East Asian Sea for monitoring and evaluating atmospheric environmental quality. Based on Aerosol Robot Network (AERONET), Visible Infrared Imaging Radiometer (VIIRS), and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) data, the temporal and spatial variation characteristics and differences of aerosol parameters and types in the East Asian Sea were studied by using figure classification method (FIGCM), aerosol optical depth (AOD)440-Angstrom exponent (AE)440-870 method (AA1M), and AOD550-AE490-670 method (AA2M). The results show that the seasonal variation trend of aerosol characteristics and types is obvious in East Asia Sea. AOD, volume concentration (Cv), and aerosol effective radius (reff) in the Bohai-Yellow Sea and the Sea of Japan in autumn are lower than those in other seasons, and the occurrence frequency of ocean-type aerosols is high. Different from the Bohai-Yellow Sea and Sea of Japan, human activities in winter, summer, and autumn seriously affect the air quality in the East China Sea and South China Sea. Especially at the Taipei CWB site, from aerosol parameters and high biomass burning/urban industrial (BB/UI) aerosol, human activity is an important factor for high pollution at the Taipei CWB site. Aerosol types of AA1M, FIGCM, AA2M, and CALIPSO were compared at Anmyon and Yonsei University sites in the Bohai-Yellow Sea in March 2020. The results show that aerosol types based on threshold classification methods generally have higher mixed aerosol results, and the marine (MA) results of AA1M, FIGCM, and AA2M are close to the clean marine aerosol results of CALIPSO. Comparing the results of AA 2M and CALIPSO on a spatial scale, it is found that the clean marine aerosol proportion identified by CALIPSO (0.38, 0.48, 0.82) is consistent with the MA proportion identified by AA 2M (0.43, 0.46, 0.97) in the East China Sea, South China Sea, and Western Pacific Ocean.

Preserved seasonal variation in glycemic control in patients with type 2 diabetes mellitus during COVID-19: a 3-year-long retrospective cohort study in older adults in Japan.

The coronavirus disease 2019 (COVID-19) pandemic has changed our lifestyle by imposing restrictions, such as physical distancing. The effect of COVID-19 prevalence on seasonal variations in glycemic control in patients with diabetes mellitus (DM) remains unknown. This single-center retrospective cohort study evaluated glycemic control in patients with type 2 DM who visited Sugi Cardiovascular Hospital in December 2021. We evaluated the clinical findings of all patients treated regularly between March 1, 2019, and December 31, 2021, including the periods both before and after the COVID-19 pandemic. All the standard treatments were approved. Furthermore, seasonal changes in hemoglobin A1c (HbA1c) levels were evaluated using stratified analyses based on age. This study analyzed 86 patients (mean age, 69.6 ± 9.2years; men, 57). Median HbA1c (National Glycohemoglobin Standardization Program [Union of Clinical Chemistry]) levels in spring (March) were 7.70% (interquartile range (IQR):7.23%-8.30%) [60.6mmol/mol (IQR:55.4-67.2mmol/mol)], 7.35% (IQR:6.90%-7.90%) [56.8mmol/mol (IQR:51.9-62.8mmol/mol)], and 7.50% (IQR:7.10%-8.00%) [58.5mmol/mol (IQR:54.1-63.9mmol/mol)] in 2019, 2020, and 2021, respectively. During these periods, HbA1c levels and body mass index (BMI) revealed significant seasonal variations "high in spring" and "low in autumn." Median HbA1c levels in spring (March) and autumn (September) were 7.86% [61.2 mmol/mol] and 7.48% [57.4 mmol/mol] in 2019 (P < 0.001), 7.50% [57.7 mmol/mol] and 7.17% [54.2 mmol/mol] in 2020 (P < 0.001), and 7.61% [58.3 mmol/mol] and 7.19% [53.8 mmol/mol] in 2021 (P < 0.001). Seasonal variations in HbA1c levels and BMI were maintained over the past 3years, including the pandemic period. None of the patients in this study developed COVID-19 during the study period. Seasonal variations in glycemic control in patients with DM were not influenced by lifestyle modifications associated with COVID-19. Maintenance of physical activity is necessary to prevent the development of sarcopenia. Moreover, seasonal variations in glycemic metabolism should be considered an independent factor for DM management. Additional extensive multifacility investigations are necessary to corroborate our findings.

Estimation of Phytoplankton Primary Productivity in Qinghai Lake Using Ocean Color Satellite Data: Seasonal and Interannual Variations

Estimation of Phytoplankton Primary Productivity in Qinghai Lake Using Ocean Color Satellite Data: Seasonal and Interannual Variations

Influence of Seasonal Variation and Anthropogenic Activities on Elemental Compositions in Zooplankton: A Year-Long Case Study from the Jeddah Coast of the Red Sea

Influence of Seasonal Variation and Anthropogenic Activities on Elemental Compositions in Zooplankton: A Year-Long Case Study from the Jeddah Coast of the Red Sea

Investigating the spatial-temporal pattern of the trophic state index in Hanoi’s largest urban lake (Vietnam) using Sentinel-2 images

ABSTRACT Urban lakes provide aesthetic, recreational and ecological benefits, making understanding their trophic status vital for effective management. Utilizing Sentinel-2 imagery, we investigated the spatial-temporal patterns of the Trophic State Index (TSI) in Hanoi’s West Lake over a 2-year period. Our study proposed a robust TSI estimation model, incorporating three band ratios: R rs 655 / R rs 490 , R rs 705 / R rs 655 , R rs 655 / R rs 443 , along with 124 in situ point data. The model exhibited high accuracy (the determination coefficient, R 2 = 0.63) and minimal errors (the root mean square errors, RMSE = 1.1 and 0.9). Consequently, West Lake consistently registered as hypereutrophic (TSI > 70), with seasonal variations linked to climate factors, leading to algal blooms and reduced water clarity. Spatial analysis highlighted the influence of sewage drains on TSI, indicating an urgent need for wastewater control. Our study demonstrates the cost-effective utility of Sentinel-2 imagery for monitoring urban lake eutrophication and emphasizes the urgency of managing eutrophication in these vital ecosystems.

Seasonal variation of limnological parameters and phytoplankton dynamics in the high-altitude oligotrophic lakes of Tawang district, Arunachal Pradesh (India)

Seasonal variation of limnological parameters and phytoplankton dynamics in the high-altitude oligotrophic lakes of Tawang district, Arunachal Pradesh (India)

Paralytic Shellfish Toxins in Mollusks from Galicia Analyzed by a Fast Refined AOAC 2005.06 Method: Toxicity, Toxin Profile, and Inter-Specific, Spatial, and Seasonal Variations

Paralytic shellfish poisoning is an important concern for mollusk fisheries, aquaculture, and public health. In Galicia, NW Iberian Peninsula, such toxicity has been monitored for a long time using mouse bioassay. Therefore, little information exists about the precise toxin analogues and their possible transformations in diverse mollusk species and environments. After the change in the European PSP reference method, a refinement of the Lawrence method was developed, achieving a 75% reduction in chromatogram run time. Since the beginning of 2021, when this refinement Lawrence method was accredited under the norm UNE-EN ISO/IEC 17025, it has been used in the area to determine the toxin profiles and to estimate PSP toxicity in more than 4500 samples. In this study, we have summarized three years of monitoring results, including interspecific, seasonal, and geographical variability of PSP toxicity and toxin profile. PSP was detected in more than half of the samples analyzed (55%), but only 4.4% of the determinations were above the EU regulatory limit. GTX1,4 was the pair of STX analogs that produced the highest toxicities, but GTX2,3 was found in most samples, mainly due to the reduction of GTX1,4 but also by the higher sensitivity of the method for this pair of analogs. STX seems to be mainly a product of biotransformation from GTX2,3. The studied species (twelve bivalves and one gastropod) accumulated and transformed PSP toxins to a different extent, with most of them showing similar profiles except for Spisula solida and Haliotis tuberculata. Two seasonal peaks of toxicity were found: one in spring-early summer and another in autumn, with slightly different toxin profiles during outbreaks in relation to the toxicity during valleys. In general, both the total toxicity and toxin profiles of the southernmost locations were different from those in the northern part of the Atlantic coast and the Cantabrian Sea, but this general pattern is modified by the PSP history of some specific locations.

Longitudinal analysis of vitamin D levels considering sunshine duration and suggestion for a standardised approach for vitamin D supplementation in children and adolescents with obesity

BackgroundChildren with obesity have low 25 hydroxy-vitamin D (25-OH-D3) levels compared to lean children. Recommendations on when to start vitamin D supplementation differ largely between countries. Longitudinal data on 25-OH-D3 levels to guide treatment decisions are scarce since they are largely influenced by solar radiation and are difficult to compare.MethodsWe carried out a retrospective analysis of multiple 25-OH-D3 and parathyroid hormone (PTH) measurements in a cohort of 543 patients without vitamin D supplementation. All measurements were taken at the local paediatric obesity clinic as documented in the German-Austrian-Swiss APV (Prospective Documentation of Overweight Children and Adolescents) registry from 2009 to 2019. Serial 25-OH-D3 and PTH levels were adjusted for sunshine duration over the last 30 days to account for seasonal variation, as well as for sex and body mass index (BMI). We further performed an exploratory analysis of the association of sunshine duration, sex, BMI SDS (standard deviation score), abnormal lipid levels or dysglycemia with the 25-OH-D3 trend.Results229 obese patients (mean BMI SDS: 2,58 (± 0,56), 53% females, mean age: 12 (± 3) years, range: 2–21 years) with two, 115 with three and 96 with four repeated 25-OH-D3 measurements were identified. Mean adjusted 25-OH-D3 (48.2 nmol/l) and PTH (34.9 ng/l) levels remained stable over 120 weeks. 5% of the patients had an elevated PTH > 65 ng/l. High total cholesterol ≥ 200 mg/dl and high triglycerides ≥ 130 mg/dl were associated with higher 25-OH-D3 levels.ConclusionWe propose a simple method to include sunshine duration in the analysis of 25-OH-D3 levels to minimise the bias of seasonal variation. Based on our data we established the pragmatic strategy of limiting vitamin D supplementation to patients with biochemical signs of mineralisation disorders such as elevated PTH and alkaline phosphatase (AP). In children with normal PTH and AP we recommend adjustment of calcium intake and increase of outdoor activity instead.

Where Birth Month, Sex and Age Matters: The Burden of Severe Respiratory Disease in Danish Children

In light of the substantial impact that respiratory diseases in young children poses on healthcare systems globally, and in the wake of the recent COVID-19 pandemic, there is a growing urgency to obtain reliable estimates on the burden of respiratory disease. The aim of this study is to quantify the overall burden of respiratory disease requiring hospitalizations and explore the trends in these admissions in Danish children <5 years, January 1, 2016-October 31, 2022. The number of hospitalizations attributed to respiratory infections in children <5 years, was extracted from the Danish National Patient Register, and stratified into subgroups based on age, gender and birth month, and presented on a month-to-month basis. A total of 48,194 children under the age of 5, were hospitalized due to respiratory infections within the study period and the annual hospitalization incidence exhibited a noteworthy variation. Risk factors associated with the highest hospitalization incidence were young age, male gender and in children under 1-year-old, birth months falling in the period of November to January. Younger age and admission during the winter months were linked to longer hospital stays. The seasonal pattern of hospitalizations and the distribution of hospitalizations across various subgroups were greatly influenced by the COVID-19 pandemic. This study describes and quantifies the importance of factoring in specific child demographics and seasonal variations in hospitalizations when devising preventive healthcare strategies such as the use of monoclonal antibody therapy and vaccines.

Seasonal impact on Q fever in sheep, Bosnia and Herzegovina

This study investigates the prevalence of Coxiella burnetii antibodies in sheep and examines the seasonal impact on Q fever distribution. A total of 253 blood samples from sheep in Bosnia and Herzegovina during summer and winter were used, and, the research employed ELISA testing for antibody detection. Findings revealed a significant seasonal variation in seroprevalence, with 41 positive cases identified: 37 in winter and 4 in summer, indicating a higher infection rate during colder months. Statistical analysis suggests a significant association (p&lt;0.05) between season and infection rates; winter conditions, increased indoor density, and lambing activities may elevate transmission risks. These results underscore the importance of considering seasonal factors in Q fever management and surveillance in sheep, contributing to a better understanding of its epidemiology and informing public health strategies. The study highlights the need for further systemic-epidemiological research across different geographies and management practices to elucidate the full impact of seasonality on Q fever prevalence.

Diversity and seasonal variation of fungal endophytes associated with Ageratum conyzoides L.: an invasive species

Diversity and seasonal variation of fungal endophytes associated with Ageratum conyzoides L.: an invasive species

Seasonal variation in the activity pattern of red squirrels and their mammalian predators

Seasonal variation in the activity pattern of red squirrels and their mammalian predators

Climatological aspects of notable tornado events in Chile

Abstract Tornadoes in Chile seem to develop in what are called “high-shear, low-CAPE” (HSLC) environments. An analysis of convective parameters from the ERA5 reanalysis during sixteen notable tornadoes in Chile showed that several increased markedly before the time of the reports. The significant tornado parameter (STP) was able to discriminate the timing and location of the tornadoes, even though it was not created with that goal. We established thresholds for the Severe Hazards in Environments with Reduced Buoyancy (SHERBE) parameter (≥1) and the STP (≤−0.3) to further identify days favorable for tornado activity in Chile. The SHERBE and STP parameters were then used to conduct a climatological analysis from 1959–2021 of the seasonal, interannual, and latitudinal variation of the environments that might favor tornadoes. Both parameters were found to have a strong annual cycle. The largest magnitudes of STP were found to be generally confined to south-central Chile, in agreement with the (sparse) tornado record. The probability of a day with both SHERBE and STP values beyond their thresholds was greatest between May and August, which aligns with the months with the most tornado reports. The number of days with both SHERBE and STP beyond their respective thresholds was found to fluctuate interanually. This result warrants further study given the known interannual variability of synoptic and mesoscale weather in Chile. The results of this study extend our understanding of tornado environments in Chile and provide insight into their spatio-temporal variability.

Climate temperature and seasonal influences on the prevalence of temporomandibular disorders in South Korea

This study aimed to explore seasonal variations in temporomandibular disorder (TMD) prevalence in South Korea, utilizing nationwide population-based big data. Data corresponding to the Korean Standard Classification of Diseases code of K07.6, which identifies TMD, were extracted from the Health Insurance Review and Assessment Service online platform for the period from 2010 to 2022. Additionally, we integrated these data with climate temperature records from the Korean Meteorological Administration. We subsequently conducted a statistical analysis of TMD patient data on a monthly and seasonal basis over the past 13 years to assess prevalence. Over the past 13 years, the number of TMD patients in Korea has steadily increased. The prevalence of TMD rose from 0.48% (224,708 out of a total population of 50,515,666) in 2010 to 0.94% (482,241 out of a total population of 51,439,038) in 2022, marking a 1.96-fold increase. Among children under 10 years of age, no significant differences were observed in TMD prevalence between boys and girls. However, a distinct female predominance emerged after the age of 10, with an average female-to-male ratio of 1.51:1. The peak prevalence of TMD occurred in individuals in their 20 s, followed by adolescents in their late 10 s. The majority of TMD patients were concentrated in Seoul and Gyeonggi province, with metropolitan areas accounting for 50% of the total patient count. Seasonally, TMD patient numbers showed no significant increase in winter compared with spring or summer. The temperature difference, defined as the absolute difference between the highest and lowest temperatures for each month, showed a positive correlation with TMD patient counts. A greater temperature difference was associated with higher patient counts. The strongest correlation between temperature differences and TMD patient numbers was observed in winter (r = 0.480, p < 0.01), followed by summer (r = 0.443, p < 0.01), and spring (r = 0.366, p < 0.05). Temperature differences demonstrated a significantly stronger correlation with the increase in the number of TMD patients than absolute climate temperatures. This aspect should be a key consideration when examining seasonal trends in TMD prevalence in South Korea.

Study on the Typical Environmental Factors in the Middle Part of Zhoushan Fishery Based on HY-1C/D and Other Multi-Source Data

This study utilizes satellite data, including HY-1C/D, along with reanalysis data, to unveil the typical environmental characteristics of the sea surface in the middle of Zhoushan fishery. The article addresses three main issues. The first one is the development of an ocean primary productivity (OPP) inversion algorithm model. The second one is the study of chlorophyll-α (Chl-α) concentration and OPP distribution characteristics in Zhoushan fishery using China’s domestically produced ocean satellite HY-1C/D CZI data. The last one is the revelation of the characteristics of typical environmental factors on the sea surface at Zhoushan fishery by combining HY-1C/D with multi-source data. The results show the following: (1) The middle part of Zhoushan fishery exhibits significant seasonal and regional variations in Chl-α concentration and OPP. Chl-α concentration ranges mainly between 0.2 and 2.9 µg/L, with higher concentrations in spring and summer and lower Chl-α concentrations in autumn and winter. Spatially, Chl-α concentration gradually decreases from west to east. The OPP in the study area ranges from 100 mg·m−2d−1 to 1000 mg·m−2d−1, with high OPP values distributed on the western side, ranging from 400 mg·m−2d−1 to 1000 mg·m−2d−1, and gradually decreasing seaward. The highest OPP occurs in summer and the lowest in winter. (2) The correlation analysis between Chl-α concentration and OPP revealed a strong positive relationship. Consequently, this study developed an empirical model for estimating OPP based on Chl-α concentration and validated its feasibility. The model applies to areas with Chl-α concentrations ranging from 0.2 to 4 µg/L. (3) The convergence of freshwater injection, multiple ocean currents, and seasonal upwelling in the study area brings about a rich supply of nutrients. Additionally, the region is characterized by suitable conditions, including optimal Chl-α concentrations, OPP, SST, salinity, currents, and geological water depths. The synergistic effect of these factors together contributed to the formation of Zhoushan fishery.

Land surface temperature and transboundary air pollution: a case of Bangkok Metropolitan Region

In a rapidly urbanizing world, heavy air pollution and increasing surface temperature pose significant threats to human health and lives, especially in densely populated cities. In this study, we took an information theory perspective to investigate the causal relationship between diel land surface temperature (LST) and transboundary air pollution (TAP) from 2003 to 2020 in the Bangkok Metropolitan Region (BMR), which includes Bangkok Metropolis and its five adjacent provinces. We found an overall increasing trend of LST over the study region, with the mean daytime LST rising faster than nighttime LST. Evident seasonal variations showed high aerosol optical depth (AOD) loadings during the dry period and low loadings at the beginning of the rainy season. Our study revealed that TAP affected diel surface temperature in Bangkok Metropolis significantly. Causality tests show that air pollutants of two adjacent provinces west of Bangkok, i.e., Nakhon Pathom and Samut Sakhon, have a greater influence on the LST of Bangkok than other provinces. Also, the bidirectional relationship indicates that air pollution has a greater impact on daytime LST than nighttime LST. While LST has an insignificant influence on AOD during the daytime, it influences AOD significantly at night. Our study offers a new approach to understanding the causal impact of TAP and can help policymakers to identify the most relevant locations that cause pollution, leading to appropriate planning and management.

Evaluation of strategies to improve the quality of Tanzania grass (Megathyrsus maximum) silage with increasing levels of mata-pasto hay (Senna obtusifolia)

Context Seasonal variations between the rain and dry seasons are the main obstacle to agricultural productivity in tropical regions, making it essential to conserve surplus for periods of scarcity. One of the limiting factors in ensiling grasses is moisture, requiring the use of additives or withering. Using a mixture of grasses and legumes can be an alternative to balance the advantages and disadvantages of both in the ensiling process, and mata-pasto hay (MPH) can be an option. Aims This study evaluated different forms of Tanzania grass (Megathyrsus maximum) and MPH silages, as well as silages with increasing levels of MPH. Methods Silages of Tanzania grass and MPH in their natural form, as well as silages with increasing doses of MPH, were evaluated for nutritional value, degradability in situ. The microbiology was also evaluated. Key results Among the types of silages, natural MPH and wilted MPH were superior to natural Tanzania grass silage. The use of MPH in Tanzania grass silages improves fermentation processes, the population of beneficial microorganisms, resulting in better nutritional value of these silages. Conclusions Natural and wilted MPH hay silages are qualitatively better compared to natural Tanzania grass silage. Increasing doses of MPH improve the quality of the silage. A recommended dose is 30% of MPH hay. Implications Adding MPH to silages is a way to reduce the negative impacts of this weed on pastures. However, further studies with the use of complementary additives are needed.

Seasonal Variation in Short-Term Ambient Air Pollutants and ST-Elevation Myocardial Infarction Admissions: An Innovative Exploration of Air Pollution’s Health Consequences

Seasonal Variation in Short-Term Ambient Air Pollutants and ST-Elevation Myocardial Infarction Admissions: An Innovative Exploration of Air Pollution’s Health Consequences

Spring erosional processes and small sapping valleys in southwestern lower Michigan, USA

AbstractTributary valleys along the Pigeon River in southwestern Michigan USA possess many previously defined criteria for sapping valleys. Direct observations of seasonal variations in groundwater levels, hydraulic gradients and water temperatures confirm that perennial springs and their streams are present in these small valleys. Estimated spring‐fed stream discharges are low and variable, but continuous. Direct observations, grain‐size distributions and bedload transport estimates indicate that significant transport of fine to medium sand occurs in all seasons.We present a process‐form model for small‐scale sapping processes. Stream terraces and paleo‐meander scarps are being modified by sapping, and elongated valleys are likely being lengthened headward by groundwater sapping. Sapping processes have been occurring for at least the past ~4,500 years after Pigeon River adjusted to a fall in base level from the Nipissing high stand to the modern level of Lake Michigan. Sapping processes are currently producing a variety of small‐scale landforms dependent on four main factors: 1) hydraulic gradients and spring discharges, 2) available grain size of material being eroded, 3) transport rate of sand bedload by spring‐fed streams and finally 4) time available for groundwater sapping process to occur.