Seasonal Trends Research Articles

Occurrence of emerging contaminants in three river basins impacted by wastewater treatment plant effluents: Spatio-seasonal patterns and environmental risk assessment

The concern on the fate and distribution of contaminants of emerging concern (CECs) is a burning topic due to their widespread occurrence and potential harmful effects. Particularly, antibiotics have received great attention due to their implications in antimicrobial resistance occurrence. The impact of wastewater treatment plants (WWTP) is remarkable, being one of the main pathways for the introduction of CECs into aquatic systems. The combination of novel analytical methodologies and risk assessment strategies is a promising tool to find out environmentally relevant compounds posing major concerns in freshwater ecosystems impacted by those wastewater effluents. Within this context, a multi-target approach was applied in three Spanish river basins affected by different WWTP treated effluents for spatio-temporal monitoring of their chemical status. Solid phase extraction followed by ultra-high-performance liquid chromatography were used for the quantification of a large panel of compounds (n = 270), including pharmaceuticals and other consumer products, pesticides and industrial chemicals. To this end, water samples were collected in four sampling campaigns at three locations in each basin: (i) upstream from the WWTPs; (ii) WWTP effluent discharge points (effluent outfall); and (iii) downstream from the WWTPs (500 m downriver from the effluent outfall). Likewise, 24-h composite effluent samples from each of the WWTPs were provided in all sampling periods. First the occurrence and distribution of these compounds were assessed. Diverse seasonal trends were observed depending on the group of emerging compounds, though COVID-19 outbreak affected variations of certain pharmaceuticals. Detection frequencies and concentrations in effluents generally exceeded those in river samples and concentrations measured upstream WWTPs were generally low or non-quantifiable. Finally, risks associated with maximum contamination levels were evaluated using two different approaches to account for antibiotic resistance selection as well. From all studied compounds, 89 evidenced environmental risk on at least one occasion in this study.

Changes in physicochemical parameters of the alpine/mountain stream influenced by summer flash flood in Tatra Mountains (Western Carpathians)

taChanges to the physicochemical parameters of water in alpine/mountain streams can provide evidence of ongoing natural and anthropogenic processes in their catchment. In this study, we analysed a mountain stream (Javorinka) on the north-eastern side of the Tatra Mountains (Western Carpathians), which is minimally influenced by human activity. The stream was monitored weekly for 5 years (2017–2021) and evaluated for its seasonal variations in physicochemical parameters. These seasonal variations were influenced by the large summer flash flood in July 2018. We hypothesise that floods are essential for the oligotrophic profile of alpine/mountain streams. To support this idea, our main objective was to compare the seasonal trends of the main physicochemical parameters in the stream before and after floods or periods of high flow. We found evidence to support our hypothesis. For example, there was a significant decrease in the chemical consumption of oxygen and ammonia, and, conversely, an increase in the ratio of saturated oxygen and nitrate concentrations. Stream bed erosion also resulted in increased phosphates (over the next 2 years) and high enrichment of the water by dissolved solids in the spring. Interestingly outside of the main objectives, we observed a significant decrease in sulphates, especially in the summer and autumn of 2020 and 2021, which may be related to suppressed emissions due to the restriction of the COVID-19 lockdown. The observed trends and their changes therefore support the idea that alpine/mountain streams are excellent indicators of ongoing environmental processes, and that occasional summer flash floods support the oligotrophic profile of the stream system.

Outdoor Radon Dose Rate in Canada's Arctic amid Climate Change.

Decades of radiation monitoring data were analyzed to estimate outdoor Radon Dose Rates (RnDRs) and evaluate climate change impacts in Canada's Arctic Regions (Resolute and Yellowknife). This study shows that the RnDR involves dynamic sources and complex environmental factors and processes. Its seasonality and long-term trends are significantly impacted by temperatures and soil-and-above water contents. From 2005 to 2022, Yellowknife's RnDR increased by +0.35 ± 0.06 nGy/h per decade, with the fastest increases occurring in cold months (October to March). The rise is largely attributable to water condition changes over time in these months, which also caused enhanced soil gas emissions and likely higher indoor radon concentrations. In Resolute, the RnDR increased between 2013 and 2022 at +0.62 ± 0.19 nGy/h (or 16% relatively) per decade in summer months, with a positive temperature relationship of +0.12 nGy/h per °C. This work also demonstrates the relevance of local climate and terrain features (e.g., typical active layer depth, precipitation amount/pattern, and ground vegetation cover) in researching climate change implications. Such research can also benefit from using supporting monitoring data, which prove effective and scientifically significant. From the perspective of external exposure to outdoor radon, the observed climate change effects pose a low health risk.

Investigation of Seasonal Variations in Glencore’s Kidd Creek Cu-Zn ore flotation

Water management in mining and mineral processing operations is becoming increasingly important in the 21st century due to water scarcity concerns and as part of a greater push for sustainability. The aim of this study is to investigate the impacts of seasonal water quality in the Glencore’s Kidd Creek copper-zinc concentrator in Timmins, Ontario, Canada.Mineralogy results indicate that the Kidd ore consists primarily of pyrite (22%) and quartz (22%), followed by pyrrhotite (9%), sphalerite (8%) and chalcopyrite (7%).Investigating the flotation of Kidd Creek ore at bench scale between March 2022 and February 2023 identified seasonal trends in both copper and zinc flotation. However, post hoc analysis could not identify which months were significant. Oxidation of the ore samples or the use of process water could have contributed to an increase in sphalerite floated to the copper concentrate by 20 to 30% in summer months. Sphalerite surfaces in July have higher intensities of copper and collector species resulting in higher zinc recovery in the copper concentrate. Species in the process water and on the mineral surfaces may partially explain the differences in performance between the spring and the summer months.

A Level 3 monthly gridded ice cloud dataset derived from 12 years of CALIOP measurements

Abstract. Clouds play important roles in weather, climate, and the global water cycle. The Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) onboard the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) spacecraft has measured global vertical profiles of clouds and aerosols in the Earth’s atmosphere since June 2006. CALIOP provides vertically resolved information on cloud occurrence, thermodynamic phase, and properties. We describe version 1.0 of a monthly gridded ice cloud product derived from over 12 years of global, near-continuous CALIOP measurements. The primary contents are monthly vertically resolved histograms of ice cloud extinction coefficient and ice water content (IWC) retrievals. The CALIOP Level 3 Ice Cloud product is built from the CALIOP Version 4.20 Level 2 5 km Cloud Profile product that, relative to previous versions, features substantial improvements due to more accurate lidar backscatter calibration, better extinction coefficient retrievals, and a temperature-sensitive parameterization of IWC. The gridded ice cloud data are reported as histograms, which provides data users with the flexibility to compare CALIOP’s retrieved ice cloud properties with those from other instruments with different measurement sensitivities or retrieval capabilities. It is also convenient to aggregate monthly histograms for seasonal, annual, or decadal trend and climate analyses. This CALIOP gridded ice cloud product provides a unique characterization of the global and regional vertical distributions of optically thin ice clouds and deep convection cloud tops, and it should provide significant value for cloud research and model evaluation. A DOI has been issued for the product: https://doi.org/10.5067/CALIOP/CALIPSO/L3_ICE_CLOUD-STANDARD-V1-00 (Winker et al., 2018).

Spatial and temporal trends of Tamanend’s bottlenose dolphin (Tursiops erebennus) strandings in South Carolina, USA, 2006–2020

Marine mammal strandings data contribute towards overall assessments of cetacean populations, including seasonal, annual and life‐history trends which result from both natural and anthropogenic causes. We conducted spatial and temporal analyses of Tamanend’s bottlenose dolphin (Tursiops erebennus) strandings in the waters of South Carolina, USA, over a 15‐year period from 2006 to 2020, with the following objectives: (1) to determine spatial and temporal trends; (2) to analyse seasonal reproductive trends; (3) to determine life‐history parameters, such as sex ratio and age class; (4) to determine the extent to which human interaction contributed to strandings; and (5) to compare stranding patterns with historical data from 1992–2005. A total of 837 strandings occurred over the study period, with a mean of 55.8 strandings per annum. The season with most strandings was Spring (April–June), while March and April had the highest number of strandings. A relatively equal number of male and females dolphins stranded, and mortality was highest in neonates, first‐year calves and adults. Neonatal strandings comprised 22.1% of all strandings and were predominant in May. Ninety‐five human‐interaction (HI) cases were observed, representing 22.9% of strandings where HI or non‐HI could be determined. Confirmed crab‐pot buoy‐line entanglements were the predominant HI category (n = 31). Density maps and hot spot analysis showed most strandings, including live and neonatal strandings and HI cases, occurred in defined areas of Charleston and Beaufort Counties. While many trends were similar to historical data, some new trends emerged, particularly an increase of strandings in March and April. Neonatal strandings decreased in November and the historical spike during this month has essentially disappeared. The results of this analysis serve as a tool to predict stranding rates and inform conservation and management decisions to better protect bottlenose dolphins.

Prediction of footwear demand using Prophet and SARIMA

In an increasingly globalized market, where world container traffic since 2000 has almost quadrupled, the prediction of demand is an element of great importance for the optimal business development of a company. This work focuses on demand forecasting in the fashion sector. It is a very volatile market, with some characteristics such as: seasonality, culture and fashion trends, that makes it difficult to estimate the inter-seasonal footwear demand. In recent years, many algorithms for the prediction of demand have been studied; they can be divided into three natures: statistical algorithms, artificial intelligence algorithms and hybrid algorithms, each of them with its own characteristics. AI-generated predictions provide business professionals with the ability to organize the purchase of materials, manage production processes and stock quantity. Therefore, the purpose of this work is to forecast the long-term sales of a highly seasonal footwear model based on its historical data, using the Prophet and SARIMA (Seasonal Autoregressive Integrated Moving Average) algorithms. This represents a novelty as sales predictions for footwear in the state of the art are not typically made over the long term or highly seasonal, and there is no model that clearly outperforms others. Additionally, a set of Key Performance Indicators has been established to evaluate the prediction outcomes, as the same indicators such as MAE, MAPE and RMSE are commonly used in the state of the art. Furthermore, a relational database structure has been proposed for the organized storage of future predictions. Finally, the results between Prophet and SARIMA have been compared to ascertain whether Prophet (a non-linear statistical algorithm) outperforms SARIMA (a linear statistical algorithm). In the model prediction Prophet obtains an accuracy of 98.8% and a 158.8 MAE, while SARIMA reaches an accuracy of 93% and a 83.9 MAE; all in all really positive results taking into account long-term prediction and high seasonality. It has been observed how Prophet provides better results when it comes to predicting results of annual quantities, for example, the number of shoes that are expected to be sold next year. However, SARIMA returns better results for those KPI that are calculated considering the monthly distribution of the prediction, as well as being 15 times faster in the mean prediction time.

Analysis of historical and future cooling degree days over Türkiye for facade design and energy efficiency in buildings

In today’s examination of optimal facade design for buildings, facade performance has a significant influence on cooling energy consumption. Cooling degree days (CDD) is regarded as a basic and straightforward approach for predicting building cooling energy consumption. Accurate seasonal trend forecasting of the CDD plays a vital role in estimating the energy demand for building cooling. Unfortunately, there are no published statistics or research on Turkey’s CDD data for the following years. The monthly mean CDD data of Türkiye were created in this study utilizing data from the Turkish State Meteorological Service for the historical period from 1991 to 2022. The Seasonal Autoregressive Integrated Moving Average (SARIMA) approach was used to model the CDD data, and a time series forecast was performed. The SARIMA model was used to forecast the future trend of CDD from 2023 to 2040. The monthly and yearly CDD statistics were presented as figures, while the yearly CDD maps for Türkiye were created using the ArcGIS software program. Finally, CDD zones that require more attention to the most appropriate facade design in terms of energy efficiency for buildings in Türkiye were identified and classified.

Space–time clusters and co-occurrence of Plasmodium vivax and Plasmodium falciparum malaria in West Bengal, India

BackgroundMalaria, a prominent vector borne disease causing over a million annual cases worldwide, predominantly affects vulnerable populations in the least developed regions. Despite their preventable and treatable nature, malaria remains a global public health concern. In the last decade, India has faced a significant decline in malaria morbidity and mortality. As India pledged to eliminate malaria by 2030, this study examined a decade of surveillance data to uncover space–time clustering and seasonal trends of Plasmodium vivax and Plasmodium falciparum malaria cases in West Bengal.MethodsSeasonal and trend decomposition using Loess (STL) was applied to detect seasonal trend and anomaly of the time series. Univariate and multivariate space–time cluster analysis of both malaria cases were performed at block level using Kulldorff’s space–time scan statistics from April 2011 to March 2021 to detect statistically significant space–time clusters.ResultsFrom the time series decomposition, a clear seasonal pattern is visible for both malaria cases. Statistical analysis indicated considerable high-risk P. vivax clusters, particularly in the northern, central, and lower Gangetic areas. Whereas, P. falciparum was concentrated in the western region with a significant recent transmission towards the lower Gangetic plain. From the multivariate space–time scan statistics, the co-occurrence of both cases were detected with four significant clusters, which signifies the regions experiencing a greater burden of malaria cases.ConclusionsSeasonal trends from the time series decomposition analysis show a gradual decline for both P. vivax and P. falciparum cases in West Bengal. The space–time scan statistics identified high-risk blocks for P. vivax and P. falciparum malaria and its co-occurrence. Both malaria types exhibit significant spatiotemporal variations over the study area. Identifying emerging high-risk areas of P. falciparum malaria over the Gangetic belt indicates the need for more research for its spatial shifting. Addressing the drivers of malaria transmission in these diverse clusters demands regional cooperation and strategic strategies, crucial steps towards overcoming the final obstacles in malaria eradication.

Solar irradiance variability around Asia Pacific: Spatial and temporal perspective for active use of solar energy

This study discusses solar irradiance variability in the spatial and temporal domains for the active use of solar energy. The spatial domain was calculated using the difference between one location and another in a focused small tile area. The principal component analysis (PCA) was used for this analysis in the spatial and temporal domain. The Umbrella Effect Index (UI) was calculated to determine the probability of an umbrella effect event within a specific time range. This study discusses solar irradiance variability using solar irradiance data analyzed every 10 min from high-temporal observations of geostationary satellites in the Asia-Pacific region. This study shows that solar heterogeneity around the Asia-Pacific ranges from 0–135 W/m2 with a high tendency in the area around the equator and highlands. In addition, this study also shows that the Asia Pacific region has umbrella effect events of approximately 50–2224 h/year with an index ranging approximately 0–0.34. This study presents the annual analysis and seasonal trends of solar irradiance variability over the entire study area. Determining seasonal trends is important because electricity demand fluctuates significantly as seasons progress. An integrated analysis of heterogeneity and UI revealed trends in spatiotemporal variations in solar irradiance. This approach provides useful information for optimizing and managing the locations for installing solar power plants. Moreover, an evaluation of existing solar power plants is presented. Evaluations based on spatiotemporal data reveal impossible characteristics using traditional approaches that use long-term simple averages or typical solar irradiance data. This research shows the distributed photovoltaic (PV) system in wide area can increase the stability of solar energy supply to the grid.

Seasonal trend and alternative host plants of drosophila suzukii in blackberry crops from Mexico

Seasonal trend and alternative host plants of drosophila suzukii in blackberry crops from Mexico

Secular trend of Kawasaki disease and its correlation with viral activity in Taiwan: a nationwide population-based study

BackgroundKawasaki disease (KD) is the most important acquired heart disease in children. This study investigated annual incidence, seasonality, secular trend and the correlation of KD incidence with viral activity in Taiwan.MethodsThrough the national health insurance database, we identified KD during 2001–2020. The viral activity was obtained from nationwide surveillance database. We analyzed KD age-specific annual incidence, secular trends, seasonality and the correlation between KD incidence and common enteric or respiratory viral activity.ResultsThe KD incidence of subjects younger than 18 years significantly increased from 2001 to 2020 (11.78 and 22.40 per 100,000 person-years, respectively), and substantially decreased with age. Infants younger than 1 year presented the highest KD annual incidence at 105.82 to 164.34 per 100,000 person-years from 2001 to 2020. For all KD patients, the most frequently occurring season was summer followed by autumn. The KD incidence of infants younger than 1 year had significantly positive correlation with enteric (r = 0.14) and respiratory (r = 0.18) viral activity.ConclusionsThis study demonstrates the increasing trend of KD annual incidence and seasonality (more in summer and autumn) in Taiwan. The activity of common respiratory and enteric viruses was significantly correlated with KD incidence in infants.

Secular trends and determinants of ad libitum energy intake measured in a research setting from 1999-2020.

Historically, secular and seasonal trend analyses have been examined using self-report measures of intake. Rarely are objective measures and known determinants of dietary intake used in these analyses. Our objective was to quantify the seasonal and secular differences in an objective ad libitum intake paradigm while considering the contribution of determinants, such as fat-free mass (FFM) index and spontaneous physical activity (SPA) limited to the restricted space of a whole-room calorimeter. For this study, recruitment of N = 292 healthy, diabetes free, adults occurred from 1999 to 2020. Assessment during their 10-day stay included body composition (by DXA), SPA (by an approximately 24-h stay in whole-room calorimetry), and ad libitum intake (by a vending machine for 3 days). This secondary analysis used general linear models (GLM) to investigate secular and seasonal differences while adjusting for sex, age, FFM index, FM (fat mass) index, SPA, and race/ethnicity. FFM index and SPA were positively associated with all intake measures (p < 0.05). In all adjusted seasonal models, season did not affect intake. Adjusted secular trends models (kcals/year) demonstrated a decrease in total kcals (β = -55), intake as percent weight maintaining energy needs (β = -2), protein kcals (β = -10), fat kcals (β = -27), and carbohydrates kcals (β = -22) (all p < 0.05). After further adjustment for SPA, significance remained in all intake measures (p < 0.05). Secular trends in body composition revealed no changes in weight, BMI, and percent body fat (all p > 0.20). Our results indicate that over time, ad libitum intake decreased in this controlled research setting and remained significant even after accounting for positive determinants of intake. A significant ad libitum decrease, coupled with no change in body composition, may highlight a participant bias toward calorie restriction in a controlled setting over time and deserves further investigation.

Revisiting the January effect anomaly: evidence from international stock markets

A recurring theme in the literature and discussion of stock market analysis is the concept of the January effect which essentially implies buy in December and sell in January. The January effect is based on the perceived seasonality trend where short term investors hope to take advantage of the arbitrage opportunity between December and January. However, this perceived anomaly continues is seen as a myth and has been strongly rejected by many market participants in the current dispensation. The purpose of this paper was to investigate the January effect in the Nikkei 225, JSE, CAC 40, DAX, and the NASDAQ Index from February 2019 to February 2024. A F-test statistics was used to explore the phenomenon. The findings indicated that there is no significant difference between the realised returns in January and those of the other month for the most recent five years. This led to the conclusion that, while the January effect may have been observed, it is no longer evident in financial markets, hence market participants should avoid using this type of arbitrage approach because it may result in massive losses

Airborne particle radioactivity during desert dust days in Cyprus

Mediterranean countries are often affected by desert dust storms, which have significant effects on the environment and public health. We compared airborne particle radioactivity levels during desert dust and non-dust days in Cyprus.Gross α- and β-radioactivity from Total Suspended Particle (TSP) samples, collected at two urban routine monitoring stations in Limassol and Nicosia, were available for the period 2017–2020 and 2008–2020, respectively. Radionuclides 137Cs and 40K, from TSP samples, were also available from a semi-industrial monitoring station in Nicosia during 2008–2020. Information on desert dust presence, dust origin, particulate matter (PM) levels, and solar activity (KP index and solar sunspot numbers - SSN) were also obtained. We used linear regression models adjusting for seasonality and long-term trends, and solar activity to assess the effect of dust storms on TSP gross α- and β-, and 137Cs and 40K radioactivity levels.Gross α- and β-radioactivity, and 137Cs and 40K radioactivity levels were significantly higher on days with desert dust compared to days characterized with no influence of desert dust. Levels of gross α- and β-radioactivity during dust days were higher when dust originated from the Middle East deserts than from the Sahara Desert. The same trend was observed for the ratios 137Cs to 40K and 137Cs to PM10. Conversely, ratios of TSP gross α- and β-radioactivity to PM10 were significantly lower during desert dust days in comparison to days without dust influence.This study suggests that desert dust increase both TSP gross α- and β-radioactivity, as well as 137Cs and 40K radioactivity levels. Further studies should clarify the contribution of anthropogenic and other natural sources to the emission or transportation of particles radioactivity, to better mitigate future exposures.

Laboratory diagnosis and epidemiological features of leptospirosis cases in a tribal region of Western Maharashtra, India: A retrospective study

PurposePalghar district, located in the coastal region of the Konkan division of Maharashtra, has a predominantly tribal population. Leptospirosis is a major neglected public health problem and is highly underreported in Palghar district. The study aimed to evaluate the seropositivity of Leptospira infection and its associated epidemiological factors in tribal areas of the Palghar district of Maharashtra. MethodsThe present retrospective study included 94 samples of patients clinically suspected of leptospirosis during a period of one year (2021–2022) tested at Model Rural Health Research Unit (MRHRU) Dahanu. The serum sample testing was done for the presence of specific Leptospira IgM antibodies using the Panbio™ Leptospira IgM ELISA kit. Leptospirosis seropositivity was correlated with various epidemiological risk factors. ResultsA total of 12 samples of patients tested positive for specific IgM antibodies by ELISA method, indicating an overall positivity of 12.8%. Among those who tested positive, fever (83.3%), headache (58.3%), myalgia (50%), redness of the eyes (50%), and calf tenderness (16.7%) were the common symptoms observed. Subjects with redness of the eyes were significantly associated with leptospirosis (p = 0.018). The highest positivity (50%) was reported from the Ganjad area of Dahanu taluka. Farmers and animal handlers were most affected by leptospirosis. ConclusionThe high proportion of Leptospirosis cases reflects the endemic nature of the disease in the Palghar district. This study shows seasonal trends in leptospirosis incidence over the year. The clinical presentation of leptospirosis may vary from sub-clinical to mild illness to severe and potentially fatal. The findings of this study will be important for achieving the overarching goal of One Health.

Seasonal variations of organophosphate esters (OPEs) in atmospheric deposition, and their contribution to soil loading

Organophosphate esters (OPEs) are ubiquitous in surface soil, and atmospheric deposition is considered to be the major pollution source. However, the research on the environmental transport behaviors of OPEs between atmospheric deposition and soil is very limited. In this study, we investigated the contamination levels and seasonal variations of OPEs in atmospheric deposition samples (n = 33) collected from an area of South China every month between February 2021 and January 2022, and evaluated the contribution of OPEs in atmospheric deposition to soil. The concentrations of ∑21target-OPEs ranged from 3670 to 18,600 ng/g dry weight (dw), with a mean of 8200 ng/g dw (median: 7600 ng/g dw). ∑21target-OPEs concentrations in all atmospheric deposition samples exhibited significant seasonal differences (p < 0.05) with higher concentrations observed in winter and lower concentrations in summer. Tris(2,4-di-tert-butylphenyl) phosphate (TDTBPP) was the most dominant target OPE in atmospheric deposition (4870 ng/g dw), and its seasonal variation trend was consistent with ∑21OPEs (p < 0.05). Simultaneously, in order to further explore the effect of atmospheric deposition on the levels of OPEs in soil of the study region, input fluxes and accumulation increments were estimated. Ten OPEs (including seven target OPEs and three suspect OPEs) exhibited high input flux means and accumulation increments, indicating that these compounds are prone to accumulate in soil via atmospheric deposition. It is noteworthy that the non-target phosphonate analyte bis(2,4-di-tert-butylphenyl) dibutyl ethane-1,2-diylbis(phosphonate) (BDTBPDEDBP) was detected at highest median concentration (8960 ng/g dw) in atmospheric deposition. Correspondingly, the average input flux and accumulation increment of BDTBPDEDBP were higher than those of all target and suspect OPEs. Collectively, this study quantifies the environmental transport behavior of OPEs between atmospheric deposition and soil, and provides new evidences for the fact that atmospheric deposition is the important pollution source of OPEs in soil.

Daily heat and mortality among people experiencing homelessness in 2 urban US counties, 2015-2022.

High and low daily ambient temperatures are associated with higher mortality in the general population. People experiencing homelessness (PEH) are thought to be particularly vulnerable, but there is almost no direct evidence available. We examined the temperature-mortality association among PEH in 2 populous, urban counties in hot-climate regions of the United States, focusing on heat effects. Study setting was Los Angeles County, CA, and Clark County, NV, which encompass the cities of Los Angeles and Las Vegas, respectively. Outcomes were 2015-2022 deaths among decedents categorized as homeless in county administrative records. We used quasi-Poisson distributed lag nonlinear models to estimate the association of mortality with daily temperatures and with 7-day lagged temperatures, adjusting for day of week, seasonality, and long-term trends. We estimated the minimum mortality temperature and fraction of mortality attributable to temperatures above and below minimum mortality temperature. The association between daily temperature and PEH mortality was skewed towards greater risk at higher temperatures, especially in Clark County. Temperature-attributable mortality equaled 50.1% of deaths in Clark County (95% CI, 29.0-62.8) and 7.0% in Los Angeles County (95% CI, 1.4-12.1). In both counties, most temperature-attributable deaths were attributable to heat rather than cold. In these hot-climate urban counties, our estimates of heat-attributable mortality among PEH were orders of magnitude greater than those reported in prior research on the general population. These results indicate that temperature vulnerability, particularly heat vulnerability, requires stronger public health and policy responses. This article is part of a Special Collection on Environmental Epidemiology.

Idiosyncratic phenology of greenhouse gas emissions in a Mediterranean reservoir

AbstractExtreme hydrological and thermal regimes characterize the Mediterranean zone and can influence the phenology of greenhouse gas (GHG) emissions in reservoirs. Our study examined the seasonal changes in GHG emissions of a shallow, eutrophic, hardwater reservoir in Spain. We observed distinctive seasonal patterns for each gas. CH4 emissions substantially increased during stratification, influenced predominantly by the increase in water temperature, net ecosystem production, and the decline in reservoir mean depth. N2O emissions mirrored CH4's seasonal trend, significantly correlating to water temperature, wind speed, and gross primary production. Conversely, CO2 emissions decreased during stratification and displayed a quadratic, rather than a linear relationship with water temperature—an unexpected deviation from CH4 and N2O emission patterns—likely associated with photosynthetic uptake of bicarbonate and formation of intracellular calcite that might be exported to sediments. This investigation highlights the imperative of integrating these idiosyncratic patterns into GHG emissions models, enhancing their predictive power.

Seasonal dynamics of global marine heatwaves over the last four decades

Marine heatwaves (MHWs), prolonged periods of abnormally high sea temperature, have greater devastating impacts on marine ecosystem services and socioeconomic systems than gradual long-term ocean warming. Despite growing evidence of increases in MHW frequency, duration, and intensity, their interseasonal variations remain unclear. Using satellite-derived daily sea surface temperature (SST) data from 1982 to 2022, this work reveals a strong seasonality in MHWs. Typically, the highest cumulative intensity, characterizing total impacts on ecosystems, occurs during the local warm seasons in most oceans, leading to a significant interseasonal difference between warm and cold seasons. The interseasonal difference is predominantly driven by air-sea heat flux, rather than oceanic horizontal advection and vertical process. An increase in these interseasonal differences is observed in mid and high latitudes, with a significant increase in the warm season and a weaker trend in the cold season. In the Equatorial Pacific and Western Equatorial Indian Ocean, intense MHWs are primarily exacerbated by the El Niño-Southern Oscillation (ENSO), which also determines interseasonal variations in MHWs. Understanding the seasonality of MHWs can help better formulate corresponding policies to reduce economic and ecological losses caused by these events and can improve the accuracy of future predictions.