Winter Mass Research Articles

Seasonal variations of size-classified aerosol-bound elements in school environments and risk factors for the prevalence of atopic diseases among pupils

Five-stage Sioutas impactors were used to collect particulate matter (PM) in 4 classrooms and the playground of a school with various educational levels near the largest industrial chemical complex in Portugal. Monitoring was carried out over a total period of 8 weeks split equally between winter and spring. Samples were analysed for its elemental composition by PIXE. The prevalence of respiratory symptoms in schoolchildren was assessed by applying the International Study of Asthma and Allergies in Childhood (ISAAC) standardised questionnaire. The mass concentration of quasi-ultrafine particles (PM0.25) was higher in winter, but lower than those reported in other studies. Elements accounted for 15.3–17.3 % and 25.6–34.1 % of the total PM10 mass in winter and spring, respectively. Elements such as K, S, Zn, Cu and Br presented a dominant mode in PM0.25, while Al, Mg, Ca, Fe and Si peaked at 2.5 μm. Throughout the campaign, Cl was the main component of the mass of PM greater than 0.5 μm in the schoolyard, while in classrooms Ca constituted the most abundant element of PM2.5-10. The results indicate that soil dust, cleaning products, biomass burning, traffic, the chemical complex and railway affected PM levels at the school. Taking paracetamol and living near roads with intense traffic of heavy vehicles were found to be statistically significant predictors of asthma symptoms, while the frequent consumption of antibiotics and children exposure to parental smoking during the first year of their life were found to increase the odds of developing symptoms of rhinitis.

Climate drives body mass changes in a mountain ungulate: shorter winters lead to heavier Alpine ibex

Climate affects seasonality and plant phenology, which can influence seasonal body mass dynamics of herbivores in temperate environments. We investigated long‐term trends of seasonal body mass changes in male Alpine ibex Capra ibex. We used SEM to test direct and indirect relationships between body mass, mass changes and environmental and climatic variables. Individually recognizable Alpine ibex were weighed repeatedly between 2000 and 2022 in Gran Paradiso National Park (Italy). Autumn mass increased substantially over these two decades, up to 15% in some age classes. Over the same time frame, both summer mass gain and winter mass loss decreased, suggesting that heavier autumn body mass was due to the cumulative effects of reduced mass loss over several winters. The environmental factor with the strongest effects on winter mass changes was the starting date of vegetation green‐up at low altitude, where ibex gather after winter to feed on new growth vegetation. Early springs led to lower winter mass loss, likely because ibex relied on stored fat for a shorter period and had greater access to forage. High population density also increased winter mass loss. Environmental conditions and resource availability, possibly also influenced by density in winter and early spring, seem therefore to directly affect the body mass dynamics of male Alpine ibex, while the effect of summer conditions appears less relevant. By affecting seasonal body mass dynamics, climate change may have consequences for life history and population dynamics of mountain herbivores, for example via earlier access of young males to reproduction.

Multiproxy tree ring reconstruction of glacier mass balance: insights from Pinus cembra trees growing near Silvretta Glacier (Swiss Alps)

Abstract. Glacier mass balance reconstructions provide a means of placing relatively short observational records into a longer-term context. Here, we use multiple proxies from Pinus cembra trees from God da Tamangur, combining tree ring anatomy and stable isotope chronologies to reconstruct seasonal glacier mass balance (i.e., winter, summer, and annual mass balance) for the nearby Silvretta Glacier over the last 2 centuries. The combination of tree ring width, radial diameter of earlywood cell lumina, and latewood radial cell wall thickness provides a highly significant reconstruction for summer mass balance, whereas for the winter mass balance, the correlation was less significant but still robust when radial cell lumina were combined with δ18O records. A combination of the reconstructed winter and summer mass balances allows the quantification of the annual mass balance of the Silvretta Glacier for which in situ measurements date back to 1919. Our reconstruction indicates a substantial increase in glacier mass during the first half of the 19th century and an abrupt termination of this phase after the end of the Little Ice Age. Since the 1860s, negative glacier mass balances have been dominant and mass losses accelerate as anthropogenic warming picks up in the Alps.

Abundance and transport of macro-litter at sea turtle nesting beach: A case study for sustainable habitat management

In the last few decades, the worldwide production and usage of plastic have increased substantially. As a consequence, a major proportion of the mismanaged plastic is leaking from the land (source) to the sea (sink) affecting the marine environment in the form of emerging contaminants. Along the east coast of India, the sandy beaches adjacent to River Rushikulya support the winter mass nesting of Olive Ridley Sea turtles. The present study assesses the beach litter density (items/m2), composition (%), probable sources, and transport pathway prior to the nesting event. Sampling was carried out at four transects covering a 400 m2 area during low tide, aggregates to 890 litter materials of 15 categories. The Clean Coast Index (CCI) shows the maximum density (moderately clean to dirty) of litter observed along the backshore and the minimum (very clean) on the foreshore. The particle tracking model carried out for two seasons i.e., southwest and northeast monsoon infers that the transporting time of the litter from river to beach varied between 3–4 and 6–7 days, respectively. Our study suggests most of the debris accumulated on the nesting beaches after the monsoonal flood. Thus, it is recommended that cleaning the beaches by engaging local fishermen prior to the nesting, installing trash booms, and managing solid wastes in the river upstream, are some of the doable, effective, and best management practices that need to be adopted for sustainable management of this turtle rookery habitat.

Interannual variability of atmospheric ammonia over the Sichuan Basin, southwestern China: Trend, sources, and implications on particle matter control

Atmospheric ammonia (NH3) is an important constituent of biogeochemical cycle and excessive NH3 in the environment results in detrimental effects on ecosystems, air quality, and human health. However, interannual variability and emission changes of NH3 remain highly uncertain, particularly for NH3 hotspot areas. Here, we identify the emission hotspots of NH3 and reveal the trend of NH3 emissions over the Sichuan Basin (SCB) based on a high-resolution map from infrared Atmospheric Sounding Interferometer (IASI) satellite observations in combination with the MEIC inventory from 2008 to 2019. IASI observations indicate that NH3 columns persistent increase over time while MEIC inventory suggests that the past increase in NH3 emissions has indeed ended in 2017 and exhibit decreasing trend afterwards. The NH3 hotspots derived from IASI mainly concentrate in the Chengdu Plain and southern SCB city cluster, which mostly agrees with MEIC emission inventory. CMAQ model simulations well reproduce PM2.5 and ammonia loading and capture observed patterns of NH3. We find that ammonium makes up 15–35% of inorganic fine PM2.5 mass in winter over the SCB. Regulation efforts focused on joint reducing 30% of NOx, SO2, and NH3 emissions could lead to basin-wide wintertime PM2.5 reduce by 10.0 μg/m3, while cutting 30% emissions of NH3 or NOx alone only yield PM2.5 reduced by 0.8 and 5.0 μg/m3, respectively. This work contributes insights on the trend and spatial pattern of NH3 source over the SCB and reveals the critical role of regulating NH3 emissions in mitigating PM2.5 pollution, shedding insights on nitrogen management strategies

Autumn mass change and winter mass loss differ between migratory and nonmigratory butterflies

Autumn mass change and winter mass loss differ between migratory and nonmigratory butterflies

Two decades of mass-balance observations on Aldegondabreen, Spitsbergen: interannual variability and sensitivity to climate change

Abstract Aldegondabreen is a relatively small (5.3 km2) land-terminating glacier located in Nordeskiöld Land of Svalbard, ~10 km southwest of Barentsburg. Cumulative mass balance during 2002–20 equalled −21.79 m w.e., which corresponds to 37% of the total mass loss. The annual mass balance (Ba) varied from −0.24 to −2.19 m w.e., while the winter mass balance (Bw) ranged between 0.36 and 0.85 m w.e. Ba and Bw were strongly correlated with the positive degree-day sums and solid precipitation amounts, respectively, measured at the Barentsburg weather station. There was also a strong correlation (r = 0.76) between Ba and Bw, which shows that winter accumulation amplifies the consecutive summer ice melt by changing the surface albedo. The trend in both observational series is not detectable because the period from 2005 to 2013 was characterized by relatively high Bw and not very negative Ba values. This was also observed on the other Svalbard glaciers, and was related to prevailing north-westerly flows over Svalbard during the summer. Therefore, the decadal periodicity of the Aldegondabreen mass balance follows general archipelago patterns that are determined by regional-scale factors. Thus, the surface mass-balance time series, which is now the longest one in the central part of the Spitsbergen Island, is representative for the archipelago.

Temperature variability over Dokriani glacier region, Western Himalaya, India

Long-term climate records which help decipher past climate variability and its impact are scarce in the tough terrain of the Himalayan region. Therefore, in order to fill the climate data gap and understand the glacier climate linkage, we developed a 231 year long (1785–2015 CE) March–June temperature record using ring-width chronology of Himalayan fir (Abies pindrow (Royle ex D.Don) Royle) for the Din Gad valley, Dokriani glacier region, Uttarkashi, Uttarakhand, in the Western Himalaya. The Din Gad, originating from the Dokriani glacier, is a meltwater river contributing to Bhagirathi catchment in the headwaters of the socio-economically vital Ganga River. The 21-year running mean of the temperature record showed 1978–1998 CE as the coldest period followed by 1925–1945 CE, and 1890–1910 CE as the warmest period followed by 1946–1966 CE over the entire time series. The reconstruction matches well with tree-ring based temperature records available from the Garhwal Himalaya. It also shows similarity to tree-ring based temperature reconstructions from the Western Himalaya, Nepal, Tibetan Plateau and Bhutan, thus displaying a regional scale climate signal. The low frequency fluctuation patterns of the March–June temperature also matches with Asia and Northern hemisphere temperature records. Reconstructed March–June temperature record showed a statistically negligible warming temperature trend during 1901–1989 CE in the 20th century. It, however, captured a warming spike from 1990s CE which continues rising into the 21st century, which is also evident in the Northern hemisphere temperature record. Moreover, temperature rise is not anomalous in the past 231 years and well within range of the rest of the series. The present temperature record exclusively from the glacier region revealed a strong linkage with the benchmark Dokriani glacier's winter mass balance (November–April) revealing mass loss (gain) episodes occurred in warm (cool) phases. This first such record from the glacier valleys in Ganga headwaters would be of great value at providing insight into past climate variability and glacier behaviour with respect to climate change in long term perspective, and thus would provide valuable information for water resource management in light of climate change.

Spatio-temporal reconstruction of winter glacier mass balance in the Alps, Scandinavia, Central Asia and western Canada (1981–2019) using climate reanalyses and machine learning

Abstract. Spatio-temporal reconstruction of winter glacier mass balance is important for assessing long-term impacts of climate change. However, high-altitude regions significantly lack reliable observations, which is limiting the calibration of glaciological and hydrological models. Reanalysis products provide estimates of snow precipitation also for remote high-mountain regions, but this data come with inherent uncertainty, and assessing their biases is difficult given the low quantity and quality of available (long-term) in situ observations. In this study, we aim at improving knowledge on the spatio-temporal variations in winter glacier mass balance by exploring the combination of data from reanalyses and direct snow accumulation observations on glaciers using machine learning. We use the winter mass balance data of 95 glaciers distributed over the European Alps, western Canada, Central Asia and Scandinavia and compare them with the total precipitation from the ERA5 and the MERRA-2 reanalysis products during the snow accumulation seasons from 1981 until 2019. We develop and apply a machine learning model to adjust the precipitation from the reanalysis products along the elevation profile of the glaciers and consequently to reconstruct the winter mass balance in both space (for glaciers without observational data) and time (filling observational data gaps). The employed machine learning model is a gradient boosting regressor (GBR), which combines several meteorological variables from the reanalyses (e.g. air temperature, relative humidity) with topographical parameters. These GBR-derived estimates are evaluated against the winter mass balance data using (i) independent glaciers (site-independent GBR) and (ii) independent accumulation seasons (season-independent GBR). Both approaches resulted in reduced biases and increased correlation between the precipitation of the original reanalyses and the winter mass balance data of the glaciers. Generally, the GBR models have also shown a good representation of the spatial (vertical elevation intervals) and temporal (years) variability of the winter mass balance on individual glaciers.

Arctic sea ice mass balance in a new coupled ice–ocean model using a brittle rheology framework

Abstract. Sea ice is a key component of the Earth's climate system as it modulates the energy exchanges and associated feedback processes at the air–sea interface in polar regions. These exchanges have been suggested to strongly depend on openings in the sea ice cover, which are associated with fine-scale sea ice deformations, but the importance of these processes remains poorly understood as most numerical models struggle to represent these deformations without using very costly horizontal resolutions (≃ 5 km). In this study, we present results from a 12 km resolution ocean–sea ice coupled model, the first that uses a brittle rheology to represent the mechanical behaviour of sea ice. This rheology has been shown to reproduce observed characteristics and complexity of fine-scale sea ice deformations at relatively coarse resolutions. We evaluate and discuss the Arctic sea ice mass balance of this coupled model for the period 2000–2018. We first assess sea ice quantities relevant for climate (volume, extent, and drift) and find that they are consistent with satellite observations. We evaluate components of the mass balance for which observations are available, i.e. sea ice volume export through Fram Strait and winter mass balance in the Arctic marginal seas for the period 2003–2018. Model values show a good match with observations, remaining within the estimated uncertainty, and the interannual variability of the dynamic contribution to the winter mass balance is generally well captured. We discuss the relative contributions of dynamics and thermodynamics to the sea ice mass balance in the Arctic Basin for 2000–2018. Using the ability of the model to represent divergence motions at different scales, we investigate the role of leads and polynyas in ice production. We suggest a way to estimate the contribution of leads and polynyas to ice growth in winter, and we estimate this contribution to add up to 25 %–35 % of the total ice growth in pack ice from January to March. This contribution shows a significant increase over 2000–2018. This coupled framework opens up new opportunities to understand and quantify the interplay between small-scale sea ice dynamics and ocean properties.

Christmas Mass Movements in the Italian Alps

Mass movements at high elevation during wintertime are rare events in the Italian Alps, but are generally large events compared to those occurring in other seasons. In a context of climate change, their interpretation is particularly challenging due to the risk implications during a highly tourist season in the mountains, and because their occurrence seemingly contradicts the attribution of recent mass movements in high-alpine environments to global warming. To shed some light on this topic, we reviewed 12 mass movements in the Italian Alps that occurred at elevations above 1500 m, documented from mid-December to January, henceforth during the Christmas period. The aim is to understand whether recent events may be related to ongoing climate and environmental changes. Even though the small number of analysed mass movements does not allow statistically based conclusions, some preliminary considerations could be drafted. We observe a seeming increase in the frequency and elevation of winter mass-movement events in the last two decades, with an increased number of failures involving rock slopes under permafrost conditions, and a transition from heavy-precipitations controlled mass movements to temperature-anomalies and -fluctuations controlled mass movements. We also show that any type of instability process can occur in winter, including debris flows, with rock falls/avalanches prevailing. These findings may partly stem from an increased number of mass-movement reports deriving from the growing attention in recent years to the impacts of climate change and their related risks. Considering the growing anthropic pressure on alpine areas even in winter, especially for tourism purposes, it is crucial to broaden our knowledge on winter mass movements by expanding and analysing a larger case history, through the opportunities offered by new technologies and citizen science.

Spatial variability in winter mass balance on Storglaciären modelled with a terrain-based approach

AbstractAlthough most processes governing the surface mass balance on mountain glaciers are well understood, the causes and extent of spatial variability in accumulation remain poorly constrained. In the present study, we couple an energy balance–snow and firn mass-balance model to terrain-based modelling routines estimating mass redistribution by snowdrift, preferential deposition and avalanching. We find this newly coupled model improves the spatial accuracy of winter balance simulations on Storglaciären, Sweden, while retaining versatility and a low computational cost. Accumulation on Storglaciären is primarily driven by direct precipitation, which is locally increased due to small-scale orographic effects. Wind-driven snow transport leads to substantial deposition in the accumulation zone and slight erosion in the ablation zone. Avalanching is the smallest contributor to winter balance, but cannot be neglected. The role of mass transporting processes in maintaining the current mass equilibrium on Storglaciären highlights the necessity to understand the links between climatic predictors and accumulation in order to accurately assess climate sensitivity.

Study on Change of the Glacier Mass Balance and Its Response to Extreme Climate of Urumqi Glacier No.1 in Tianshan Mountains in Recent 41 Years

Glaciers are susceptible indicators of climate change and crucial parts of the world’s water cycle. In the context of global warming, we took the Urumqi Glacier No.1 (UG1) as an example, which is situated at the source of the Urumqi River on the northern slope of the Tianshan Mountains, Xinjiang, combined with the climate data of Daxigou Meteorological Station from 1980 to 2020, and the change of glacier mass balance and its response to extreme climate are discussed. The results suggest that the glacier mass balance of UG1 showed a downward trend over the studied 41-year period, and the mass loss increased. The cumulative glacier mass balance value was −19,776 mm w.e., and the average annual value was −482 mm w.e.a−1. The Mann-Kendall trend test showed that the change point occurred around 1994, and the mass balance of UG1 became more negative after 1994. In the same period, the changing mass balance trend of UG1 was not the same in different seasons. The inter-annual variation of summer mass balance was drastic, showing a marked downward trend; the inter-annual change of winter mass balance was small, showing a slight uptrend. The changing of extreme climate indices where UG1 is located showed that only TX90p and TX10p changed observably from 1980 to 2020, and the extreme precipitation indices changed evidently and had been on the rise. The changing trend of extreme climate indices indicated that the temperature was rising, the warming was significant, and the precipitation was increasing. During 1980–2020, the glacier mass balance was substantially correlated with the extreme temperature indices (TX90p, TXx) but not with the extreme precipitation indices. Analyzing on a seasonal scale, the summer mass balance was memorably correlated with the extreme temperature indices (TX90p, TX10p, TXx), and the correlation coefficient between winter mass balance and the extreme precipitation index R95p and winter precipitation was in the range 0.36~0.40 (p < 0.05). According to the correlation between glacier mass balance and extreme climate indices, the summer mass balance was mainly affected by temperature, and the winter mass balance was affected primarily by precipitation.

On the Shift of Glacier Equilibrium Line Altitude (ELA) under the Changing Climate

Presently available information on the glacier equilibrium line altitude (ELA) is being collected and examined. The historical course of the world’s longest ELA series of 107 years at the Claridenfirn is reviewed together with climatic elements. Further, the changes in ELAs of 70 glaciers the world over are investigated, and a linear plane model for the speed of the ELA shift is proposed as a function of the changing rates of summer temperature and winter mass balance. The four glaciers in Europe, which diverge most from the plane, are investigated in detail. The cause of the divergence is likely due to be the change in solar global radiation. Although a precise quantification of the role of radiation is not possible at this stage for the entire world, the role of solar radiation is investigated for these glaciers. Globally viewed, ten, or 15% of the 70 investigated glaciers, are expected to lose their accumulation areas within the next ten years. Half of all studied glaciers will follow the same fate by the end of this century under the present climatic conditions. If climate change is accelerated, the disappearance of glaciers will occur sooner than presented in this study.

Non-Stationarity of Aerosol Extinction Coefficient per Unit of Mass in Autumn and Winter in Chengdu, China

Based on hourly observation data from the aethalometer and GRIMM180 environment particle monitor as well as the simultaneous data of visibility (V), relative humidity (RH) and nitrogen dioxide (NO2) from October to December in 2017 in Chengdu, the corresponding time series of aerosol extinction coefficient per unit of mass is retrieved. The generalized additive models (GAMs) are adopted to analyze the non-stationarity of the time series of aerosol extinction coefficient per unit of mass and to explore the responses of the aerosol extinction coefficient per unit of mass to the aerosol component structure factors (ρBC/ρPM10, ρPM1/ρPM2.5, ρPM1~2.5/ρPM2.5 and ρPM2.5/ρPM10; ρ represents particle mass concentration) and RH. The results show that through the comparative analysis of stationary and non-stationary models, the time series of aerosol extinction coefficient per unit of mass in autumn and winter in Chengdu is non-stationary. In addition, the RH and aerosol component structure factors are all significant nonlinear covariates that affect the non-stationarity of the aerosol extinction coefficient per unit of mass. According to the influence of covariates, the sequence is as follows: RH > ρBC/ρPM10 > ρPM2.5/ρPM10 > ρPM1/ρPM2.5. At PM2.5 pollution concentration (ρPM2.5 > 75 μg m−3), according to the influence of covariates, the sequence is as follows: RH > ρPM1~2.5/ρPM2.5 > ρBC/ρPM10 > ρPM2.5/ρPM10. Moreover, the interaction between RH and aerosol component structure factors significantly affects the aerosol extinction coefficient per unit of mass. The condition of high RH, high ρPM2.5/ρPM10, high ρPM1/ρPM2.5 and low ρBC/ρPM10 has a synergistic amplification effect on the increase of the aerosol extinction coefficient per unit of mass. At PM2.5 pollution concentration, the synergistic effect of high RH, high ρPM2.5/ρPM10, high ρPM1~2.5/ρPM2.5 and low ρBC/ρPM10 is beneficial to the increase of the aerosol extinction coefficient per unit of mass.

Obligatory homeothermy of mesic habitat-adapted African striped mice, Rhabdomys pumilio, is governed by seasonal basal metabolism and year-round 'thermogenic readiness' of brown adipose tissue.

Small mammals undergo thermoregulatory adjustments in response to changing environmental conditions. Whereas small heterothermic mammals can employ torpor to save energy in the cold, homeothermic species must increase heat production to defend normothermia through the recruitment of brown adipose tissue (BAT). Here, we studied thermoregulatory adaptation in an obligate homeotherm, the African striped mouse (Rhabdomys pumilio), captured from a subpopulation living in a mesic, temperate climate with marked seasonal differences. Basal metabolic rate (BMR), non-shivering thermogenesis (NST) and summit metabolic rate (Msum) increased from summer to winter, with NST and Msum already reaching maximal rates in autumn, suggesting seasonal preparation for the cold. Typical of rodents, cold-induced metabolic rates were positively correlated with BAT mass. Analysis of cytochrome c oxidase (COX) activity and UCP1 content, however, demonstrated that thermogenic capacity declined with BAT mass. This resulted in seasonal differences in NST being driven by changes in BMR. The increase in BMR was supported by a comprehensive anatomical analysis of metabolically active organs, revealing increased mass proportions in the cold season. The thermoregulatory response of R. pumilio was associated with the maintenance of body mass throughout the year (48.3±1.4 g), contrasting large summer-winter mass reductions often observed in Holarctic rodents. Collectively, bioenergetic adaptation of this Afrotropical rodent involves seasonal organ adjustments influencing BMR, combined with a constant thermogenic capacity dictated by trade-offs in the thermogenic properties of BAT. Arguably, this high degree of plasticity was a response to unpredictable cold spells throughout the year. Consequently, the reliance on such a resource-intensive thermoregulatory strategy may expose more energetic vulnerability in changing environments of food scarcity and extreme weather conditions due to climate change, with major ramifications for survival of the species.

Carbonaceous aerosol and inorganic ions of PM2.5 in Yangon and Mandalay of Myanmar: Seasonal and spatial variations in composition and sources

To characterize the seasonal and spatial patterns of the concentration, composition and sources of the atmospheric fine particles in Myanmar, 72 p.m.2.5 samples were collected during 2016 and 2017 at two urban sites in Yangon and Mandalay, representative coastal and inland cities in Myanmar, with the concentrations of organic carbon (OC), elemental carbon (EC), water-soluble organic carbon (WSOC) and the water-soluble ions being measured. Significantly higher average concentration of PM2.5 was found in Mandalay (147 μg m−3) during the sampling periods than that in Yangon (77 μg m−3). High contribution of organic matter (averaged at 48% and 37% by mass in winter and summer) and low contribution of secondary ions (<15% except that in summer Yangon) were found in both Yangon and Mandalay. Higher contribution of mineral dust to PM2.5 was found in Mandalay compared to Yangon. Meanwhile, higher average concentrations of SO42− and NH4+ in Yangon indicated a higher contribution from coal usage in Yangon. Correlation analysis and the compositional change during the rainfall event (2017/4/14–16 in Yangon) indicated that NO3− was mainly associated with Ca2+, and the high temperature and low humidity during the dry season in Myanmar inhibited the formation of NH4NO3. Regional transport of pollutants should be the important cause of the different seasonal variations for the measured species in Yangon and Mandalay besides the seasonal differences in emission sources. Positive matrix factorization (PMF) analysis showed that vehicle emissions, biomass burning, mineral dust, secondary formation and sea salt were the main sources of PM2.5 in Myanmar.

How does mass loss compare with total body score when assessing decomposition of human and pig cadavers?

Providing accurate and reliable measures of decomposition is paramount for forensic research where decomposition progress is used to estimate time of death. Mass loss is routinely used as a direct measure of biomass decomposition in ecological studies, yet few studies have analysed mass loss in a forensic context on human cadavers to determine its usefulness for modelling the decomposition process. Mass loss was examined in decomposing human and pig cadavers, and compared with other common decomposition metrics, such as total body score (TBS). One summer and one winter field decomposition experiment was conducted using human and pig cadavers, as pigs are often used as proxies for human cadavers in forensic research. The two measures of decomposition revealed two contrasting patterns of decomposition on pigs and humans, particularly in winter where TBS stabilised at similar values, but mass loss differed greatly. Mass loss was found to be faster in pigs than humans during early decomposition. Pigs lost 75% of their mass in winter, while humans lost less than 50%; however, in summer, both lost around 80% of their mass. TBS displayed similar patterns in both experiments, with TBS increasing more rapidly in pigs compared with humans but both eventually reaching similar TBS values in late decomposition. Measuring mass loss can provide additional information about decomposition progress that is missed if using TBS only. Key differences in decomposition progress between cadaver types were also observed, suggesting caution when extrapolating data from pigs to humans for forensic research and decomposition modelling.

Apparent winterkill of Painted Turtle (&lt;i&gt;Chrysemys picta&lt;/i&gt;)

Around the margin of an artificial pond in Ottawa, Ontario, we found 25 Painted Turtles (Chrysemys picta) that appeared to have died over the course of two winters (17 during the first winter and eight during the second). We examined meteorological data to try to determine the cause of the mortality. Summer and fall rains were only slightly below normal in both years, suggesting water levels should have been close to normal. The winter air temperature was warmer than normal and winter snowfall was slightly above normal in both years. Unseasonable weather does not appear to be responsible for the winter mortality and the pond’s maximum depth of 1.7 m should prevent freezing to the bottom. It is possible that the artificial nature of the pond creates suboptimal overwintering habitat, rendering the site an ecological trap; however, there is no direct evidence to support this theory. It is also possible that winter mortality of turtles is widespread at temperate wetlands, but that dead turtles were more detectable at this site because of the bare shoreline around the pond. Winter mass mortality events, if common, may represent an additional threat to turtle populations, which are declining from various anthropogenic threats.

Seasonality of Aerosol Sources Calls for Distinct Air Quality Mitigation Strategies.

An Aerosol Chemical Speciation Monitor (ACSM) was deployed to investigate the temporal variability of non-refractory particulate matter (NR-PM1) in the coastal city of Galway, Ireland, from February to July 2016. Source apportionment of the organic aerosol (OA) was performed using the newly developed rolling PMF strategy and was compared with the conventional seasonal PMF. Primary OA (POA) factors apportioned by rolling and seasonal PMF were similar. POA factors of hydrocarbon-like OA (HOA), peat, wood, and coal were associated with domestic heating, and with an increased contribution to the OA mass in winter. Even in summer, sporadic heating events occurred with similar diurnal patterns to that in winter. Two oxygenated OA (OOA) factors were resolved, including more-oxygenated OOA and less-oxygenated OOA (i.e., MO-OOA and LO-OOA, accordingly) which were found to be the dominant OA factors during summer. On average, MO-OOA accounted for 62% of OA and was associated with long-range transport in summer. In summer, compared to rolling PMF, the conventional seasonal PMF over-estimated LO-OOA by nearly 100% while it underestimated MO-OOA by 30%. The results from this study show residential heating and long-range transport alternately dominate the submicron aerosol concentrations in this coastal city, requiring different mitigation strategies in different seasons.