Multi-decadal warming alters predator's effect on prey community composition.

Predator responses to warming can occur via phenotypic plasticity, evolutionary adaptation or a combination of both, changing their top-down effects on prey communities. However, we lack evidence of how warming-induced evolutionary changes in predators may influence natural food webs. Here, we ask whether wild fish subject to warming across multiple generations differ in their impacts on prey communities compared with their nearby conspecifics experiencing a natural thermal regime. We carried out a common garden mesocosm experiment with larval perch (Perca fluviatilis), originating from a heated or reference coastal environment, feeding on zooplankton communities under a gradient of experimental temperatures. Overall, in the presence of fish of heated origin, zooplankton abundance was higher and did not change with experimental warming, whereas in the presence of fish of unheated origin, it declined with experimental temperature. Responses in zooplankton taxonomic and size composition suggest that larvae of heated origin consume more large-sized taxa as the temperature increases. Our findings show that differences between fish populations, potentially representing adaptation to their long-term thermal environments, can affect the abundance, biomass, size and species composition of their prey communities. This suggests that rapid microevolution in predators to ongoing climate warming might have indirect cross-generational ecological consequences propagating through food webs.

Linkage between temperature sensitivity of SOM decomposition and microbial communities depends on soil fractions.

The magnitude of terrestrial carbon (C)-climate feedback largely depends on the temperature sensitivity of soil organic matter (SOM) decomposition (Q10). However, our understanding of determinants of Q10 for SOM fractions such as particulate and mineral-associated organic matter (POM and MAOM, respectively) is still inadequate. Particularly, it remains unclear whether microbial effects on Q10 are fraction-dependent, which induces large uncertainties in projecting soil C dynamics. Here, we conducted large-scale topsoil sampling on the Tibetan Plateau, in combination with SOM fractionation and 300-day laboratory incubation to assess SOM fraction-dependent linkages between Q10 and microbial properties. We found that compared with MAOM, POM had larger Q10 and greater microbial diversity, and also structured distinct microbial communities as well as their co-occurrence patterns. Furthermore, associations of Q10 with microbial properties differed between the two SOM fractions. Bacterial community composition and relative abundance of bacterial keystone taxa affected Q10 for POM and MAOM respectively, while bacterial alpha diversity showed opposite relationships with Q10 for POM and MAOM. These findings highlight the necessity of incorporating SOM fraction-dependent microbial properties and their linkages with Q10 into Earth system models to accurately predict terrestrial C-climate feedback.

Variability in thermal tolerance of clutches from different mothers indicates adaptation potential to climate warming in sea turtles.

The current climate warming is a challenge to biodiversity that could surpass the adaptation capacity of some species. Hence, understanding the means by which populations undergo an increase in their thermal tolerance is critical to assess how they could adapt to climate warming. Specifically, sea turtle populations could respond to increasing temperatures by (1) colonizing new nesting areas, (2) nesting during cooler times of the year, and/or (3) by increasing their thermal tolerance. Differences in thermal tolerance of clutches laid by different females would indicate that populations have the potential to adapt by natural selection. Here, we used exhaustive information on nest temperatures and hatching success of leatherback turtle (Dermochelys coriacea) clutches over 14 years to assess the occurrence of individual variability in thermal tolerance among females. We found an effect of temperature, year, and the interaction between female identity and nest temperature on hatching success, indicating that clutches laid by different females exhibited different levels of vulnerability to high temperatures. If thermal tolerance is a heritable trait, individuals with higher thermal tolerances could have greater chances of passing their genes to following generations, increasing their frequency in the population. However, the high rate of failure of clutches at temperatures above 32°C suggests that leatherback turtles are already experiencing extreme heat stress. A proper understanding of mechanisms of adaptation in populations to counteract changes in climate could greatly contribute to future conservation of endangered populations in a rapidly changing world.

Review of the protist Labyrinhula spp. and its relationship to seagrass disease under the influence of anthropogenic activities.

Anthropogenic activities are driving significant changes in coastal ecological environments, increasingly spotlighting microorganisms associated with seagrass bed ecosystems. Labyrinthula is primarily recognized as a saprophytic protist associated with marine detritus, and it also acts as an opportunistic pathogen affecting marine algae, terrestrial plants and mollusks, especially in coastal environments. The genus plays a key role in the decomposition of marine detritus, facilitated by its interactions with diatoms and through the utilization of a diverse array of carbohydrate-active enzymes to decompose seagrass cell walls. However, human activities have significantly influenced the prevalence and severity of seagrass wasting disease (SWD) through factors such as climate warming, increased salinity and ocean acidification. The rise in temperature and salinity, exacerbated by human-induced climate change, has been shown to increase the susceptibility of seagrass to Labyrinthula, highlighting the adaptability of pathogen to environmental stressors. Moreover, the role of seagrass in regulating pathogen load and their immune response to Labyrinthula underscore the complex dynamics within these marine ecosystems. Importantly, the genotype diversity of seagrass hosts, environmental stress factors and the presence of marine organisms such as oysters, can influence the interaction mechanisms between seagrass and Labyrinthula. Besides, these organisms have the potential to both mitigate and facilitate pathogen transmission. The complexity of these interactions and their impacts driven by human activities calls for the development of comprehensive multi-factor models to better understand and manage the conservation and restoration of seagrass beds.

Assessing the impact of climate warming on tree species composition and distribution in the forest region of Northeast China.

Global climate change has markedly influenced the structure and distribution of mid-high-latitude forests. In the forest region of Northeast China, the magnitude of climate warming surpasses the global average, which presents immense challenges to the survival and habitat sustainability of dominant tree species. We predicted the potential changes in aboveground biomass, dominant tree species composition, and distribution in the forest region of Northeast China over the next century under different climatic conditions encompassing the current scenario and future scenarios (RCP2.6, RCP4.5, and RCP8.5). Forest ecosystem process model LINKAGES 3.0 was used to simulate dynamic changes in species-level aboveground biomass under four climate scenarios at the homogeneous land-type unit level. The potential spatial distribution of tree species was investigated based on three indicators: extinction, colonization, and persistence. The results showed that LINKAGES 3.0 model effectively simulated the aboveground biomass of 17 dominant tree species in the forest region of Northeast China, achieving a high accuracy with R² = 0.88. Under the current, RCP2.6, and RCP4.5 climate scenarios, the dominant tree species presented gradual increases in aboveground biomass, whereas under RCP8.5, an initial increase and subsequent decline were observed. With increasing warming magnitude, cold-temperate coniferous tree species will gradually be replaced by other temperate broad-leaved tree species. Furthermore, a large temperature increase under RCP8.5 will likely produce a significant contraction in the potential distribution range of tree species like Larch, Scotch pine, Ribbed birch, Spruce and Fir, while most temperate broad-leaved tree species and Korean pine are expected to demonstrate a northward migration. These findings provide guidance for enhancing the adaptability and resilience of forest ecosystems in middle and high latitudes and addressing the threats posed by climate warming.

Identifying climate refugia for wild yaks (Bos mutus) on the Tibetan Plateau.

Climate change is threatening fragile alpine ecosystems and their resident ungulates, particularly the wild yak (Bos mutus) that inhabits alpine areas between the tree line and glaciers on the Tibetan Plateau. Although wild yaks tend to shift habitats in response to changes in climatic factors, the precise impacts of climate change on their habitat distribution and climate refugia remain unclear. Based on over 1000 occurrence records, the maximum entropy (MaxEnt) algorithm was applied to simulate habitat ranges in the last glacial maximum (LGM), Mid-Holocene, current stage, and three greenhouse gas emission scenarios in 2070. Three habitat patches were identified as climate refugia for wild yaks that have persisted from the LGM to the present and are projected to persist until 2070. These stable areas account for approximately 64% of the current wild yak habitat extent and are sufficiently large to support viable populations. The long-term persistence of these climate refugia areas is primarily attributed to the unique alpine environmental features of the Tibetan Plateau, where relatively stable arid or semi-arid climates are maintained, and a wide range of forage resource supplies are available. However, habitat loss by 2070 caused by insufficient protection is predicted to lead to severe fragmentation in the southeastern and northwestern Kunlun, Hengduan, central-western Qilian, and southern Tanggula-northern Himalaya Mountains. Habitat disturbance has also been caused by increasing anthropogenic effects in the southern Tanggula and northern Himalaya Mountains. We suggest that sufficient protection, transboundary cooperation, and community involvement are required to improve wild yak conservation efforts. Our combined modeling method (MaxEnt-Zonation-Linkage Mapper-FRAGSTAT) can be utilized to identify priority areas and linkages between habitat patches while assessing the conservation efficiency of protected areas and analyzing the coupled relationship between climate change and anthropogenic impacts on the habitat distribution of endangered species.

Seasonal-Spatial Distribution Variations and Predictions of Loliolus beka and Loliolus uyii in the East China Sea Region: Implications from Climate Change Scenarios.

Global climate change profoundly impacts the East China Sea ecosystem and poses a major challenge to fishery management in this region. In addition, closely related species with low catches are often not distinguished in fishery production and relevant data are commonly merged in statistics and fishing logbooks, making it challenging to accurately predict their habitat distribution range. Here, merged fisheries-independent data of the closely related squid Loliolus beka (Sasaki, 1929) and Loliolus uyii (Wakiya and Ishikawa, 1921) were used to explore the construction and prediction performance of species distribution models. Data in 2018 to 2019 from the southern Yellow and East China Seas were used to identify the seasonal-spatial distribution characteristics of both species, revealing a boundary line at 29.00° N for L. uyii during the autumn, with the highest average individual weight occurring during the summer, with both larvae and juveniles occurring during the autumn. Thus, the life history of L. uyii can be divided into winter-spring nursery and summer-autumn spawning periods. L. beka showed a preference for inshore areas (15-60 m) during the summer and offshore areas (32.00-78.00 m) during the winter. High-value areas of both species included inshore areas of the southern Yellow and mid-East China Seas during the autumn, enlarging during the spring to include central areas of the survey region, before significantly decreasing during the summer. Therefore, this study provides both a novel perspective for modeling biological habitat distribution with limited data and a scientific basis for the adjustment of fishery resource management and conservation measures in the context of climate change.

Evaluation of pulse-jet baghouse dust collectors' contribution to CO2 emissions.

Dust cleaning systems are mandatory for use almost in any manufacturing process. Their market size is expected at US$10.77 billion by 2030 growing from US$7.28 billion in 2022. Removing dust particles is the main purpose of these systems and they make an invaluable contribution to environmental safety. However, while cleaning the air from solid particles, industrial pulse-jet baghouse collectors have an additional impact on the environment that usually is not considered. An analysis of energy consumption at the manufacturing and operation stages of the baghouse dust collectors allows for the evaluation of CO2 emissions. The analysis shows that, given the current state of affairs in the industry, by 2030 manufacturing and operation of baghouse dust collectors over the world will emit 70+ million tons of carbon dioxide additionally to the levels of 2021. To reduce the CO2-related environmental impact of industrial pulse-jet baghouse collectors, among all scientific and technical measures, it is recommended to simply scale up the dust collection system, which involves replacing several low-capacity collectors with one general-capacity collector within one industrial enterprise. This allows for a reduction in energy consumption at the collector manufacturing stage from 3 to 10 times and also ensures a significant reduction in operation energy consumption of the dust collector during its service life.

Species-specific differences and temperature-dependence of Na+/K+-ATPase in freshwater mussels Anodonta anatina and Unio tumidus (Bivalvia: Unionidae).

The predicted global warming of surface waters can be challenging to aquatic ectotherms like freshwater mussels. Especially animals in northern temperate latitudes may face and physiologically acclimate to significant stress from seasonal temperature fluctuations. Na+/K+-ATPase enzyme is one of the key mechanisms that allow mussels to cope with changing water temperatures. This enzyme plays a major role in osmoregulation, energy control, ion balance, metabolite transport and electrical excitability. Here, we experimentally studied the effects of temperature on Na+/K+-ATPase activity of gills in two freshwater mussel species, Anodonta anatina and Unio tumidus. The study animals were acclimated to three ambient temperatures (+4, +14, +24 °C) and Na+/K+-ATPase activity was measured at those temperatures for each acclimation group. Both species had their highest gill Na+/K+-ATPase activity at the highest acclimation temperature. Na+/K+-ATPase activity of gills exhibited species-specific differences, and was higher in A. anatina than U. tumidus in all test groups at all test temperatures. Temperature dependence of Na+/K+-ATPase was confirmed in both species, being highest at temperatures between +4 and + 14 °C when Q10 values in the acclimation groups varied between 5.06 and 6.71. Our results underline the importance of Na+/K+-ATPase of gills for the freshwater mussels in warming waters. Because Na+/K+-ATPase is the driving force behind ciliary motion, our results also suggest that in warming waters A. anatina may be more tolerant at sustaining vigorous ciliary action (associated with elevated respiration rates and filter-feeding) than U. tumidus. Overall, our results indicate great flexibility of the mussel's ecophysiological characteristics as response to changing conditions.

Seasonal variations in soil microbial community co-occurrence network complexity respond differently to field-simulated warming experiments in a northern subtropical forest.

Global warming may reshape seasonal changes in microbial community diversity and co-occurrence network patterns, with significant implications for terrestrial ecosystem function. We conducted a 2-year in situ field simulation of the effects of warming on the seasonal dynamics of soil microbial communities in a northern subtropical Quercus acutissima forest. Our study revealed that warming had no significant effect on the richness or diversity of soil bacteria or fungi in the growing season, whereas different warming gradients had different effects on their diversity in the nongrowing season. Warming also changed the microbial community structure, increasing the abundance of some thermophilic microbial species and decreasing the abundance of some symbiotrophic microorganisms. The co-occurrence network analysis of the microbial community showed that warming decreased the complexity of the intradomain network in the soil bacterial community in the growing and nongrowing seasons but increased it in the fungal community. Moreover, increasing warming temperatures increased the complexity of the interdomain network between bacteria and fungi in the growing season but decreased it in the nongrowing season, and the keystone species in the interdomain network changed with warming. Warming also reduced the proportion of positive microbial community interactions, indicating that warming reduced the mutualism, commensalism, and neutralism of microorganisms as they adapted to soil environmental stress. The factors affecting the fungal community varied considerably across warming gradients, with the bacterial community being significantly affected by soil temperature, MBC, NO3--N and NH4+-N, moreover, SOC and TN significantly affected fungal communities in the 4 °C warming treatment. These results suggest that warming increases seasonal differences in the diversity and complexity of soil microbial communities in the northern subtropical region, significantly influencing soil dynamic processes regulating forest ecosystems under global warming.

Greater influences of nitrogen addition on priming effect in forest subsoil than topsoil regardless of incubation warming.

Subsoil (below 20 cm), storing over 50 % of soil organics carbon (SOC) within the 1 m depth, plays a critical role in regulating climate and ecosystem function. However, little was known on the changes in SOC decomposition induced by exogenous C input (i.e., priming effect) across the whole soil profile under nitrogen (N) enrichment and climate warming. We designed an incubation system of soil columns with minor physical disturbance, which allows the manual additions of exogenous C and N and incubation under ambient or elevated temperature. A negative priming effect by glucose was observed in all layers of ambient soil, while the negative priming effect was enhanced by soil depth but inhibited by warming. Nitrogen addition shifted the priming effect from negative to positive under ambient temperature, and decreased the magnitude of negative priming effect under elevated temperature. Nitrogen uplift effect on priming effect was more pronounced in subsoil compared to topsoil, while this effect diminished with rising temperature. Soil microbial activity (e.g., the CO2 production within 3 days) and acid phosphatase activity had important roles in regulating the variations in priming effect across the soil profile. Our results indicated that increase in labile substrate (e.g., exogenous C input) input would not lead to native SOC destabilization in subsoil, N addition shifted the priming effect from negative to positive, increasing the SOC decomposition under ambient temperature, while labile C input together with N addition benefited SOC sequestration by inducing negative priming effects in forest soil under warming climate.

Warming alters cascading effects of a dominant arthropod predator on fungal community composition in the Arctic.

Rapid climate change in the Arctic is altering microbial structure and function, with important consequences for the global ecosystem. Emerging evidence suggests organisms in higher trophic levels may also influence microbial communities, but whether warming alters these effects is unclear. Wolf spiders are dominant Arctic predators whose densities are expected to increase with warming. These predators have temperature-dependent effects on decomposition via their consumption of fungal-feeding detritivores, suggesting they may indirectly affect the microbial structure as well. To address this, we used a fully factorial mesocosm experiment to test the effects of wolf spider density and warming on litter microbial structure in Arctic tundra. We deployed replicate litter bags at the surface and belowground in the organic soil profile and analyzed the litter for bacterial and fungal community structure, mass loss, and nutrient characteristics after 2 and 14 months. We found there were significant interactive effects of wolf spider density and warming on fungal but not bacterial communities. Specifically, higher wolf spider densities caused greater fungal diversity under ambient temperature but lower fungal diversity under warming at the soil surface. We also observed interactive treatment effects on fungal composition belowground. Wolf spider density influenced surface bacterial composition, but the effects did not change with warming. These findings suggest a widespread predator can have indirect, cascading effects on litter microbes and that effects on fungi specifically shift under future expected levels of warming. Overall, our study highlights that trophic interactions may play important, albeit overlooked, roles in driving microbial responses to warming in Arctic terrestrial ecosystems. IMPORTANCE: The Arctic contains nearly half of the global pool of soil organic carbon and is one of the fastest warming regions on the planet. Accelerated decomposition of soil organic carbon due to warming could cause positive feedbacks to climate change through increased greenhouse gas emissions; thus, changes in ecological dynamics in this region are of global relevance. Microbial structure is an important driver of decomposition and is affected by both abiotic and biotic conditions. Yet how activities of soil-dwelling organisms in higher trophic levels influence microbial structure and function is unclear. In this study, we demonstrate that predicted changes in abundances of a dominant predator and warming interactively affect the structure of litter-dwelling fungal communities in the Arctic. These findings suggest predators may have widespread, indirect cascading effects on microbial communities, which could influence ecosystem responses to future climate change.

Experimental Warming Increased Cooked Rice Stickiness and Rice Thermal Stability in Three Major Chinese Rice Cropping Systems.

Climate warming is a critical environmental issue affecting rice production. However, its effects on cooked rice texture and rice thermal properties remain unstudied in China. To address this gap, we conducted a two-year multi-site field warming experiment using free-air temperature increase facilities across three major Chinese rice cropping systems. Interestingly, warming had a minimal impact on the hardness of cooked rice, while it significantly increased stickiness by an average of 16.3% under warming conditions. Moreover, compared to control treatments, rice flour exhibited a significant increase in gelatinization enthalpy, onset, peak, and conclusion temperatures under warming conditions, with average increments of 8.7%, 1.00 °C, 1.05 °C, and 1.17 °C, respectively. In addition, warming significantly declined the amylose content, remarkedly elevated the protein content and relative crystallinity, and altered the weight distribution of the debranched starch. Correlation analysis revealed significant relationships between cooked rice stickiness, rice flour thermal properties, amylose content, protein content, and partial starch structures. Therefore, warming-induced alterations in rice composition and starch structure collectively enhanced cooked rice stickiness and rice thermal stability.

A circumpolar study unveils a positive non-linear effect of temperature on arctic arthropod availability that may reduce the risk of warming-induced trophic mismatch for breeding shorebirds.

Seasonally abundant arthropods are a crucial food source for many migratory birds that breed in the Arctic. In cold environments, the growth and emergence of arthropods are particularly tied to temperature. Thus, the phenology of arthropods is anticipated to undergo a rapid change in response to a warming climate, potentially leading to a trophic mismatch between migratory insectivorous birds and their prey. Using data from 19 sites spanning a wide temperature gradient from the Subarctic to the High Arctic, we investigated the effects of temperature on the phenology and biomass of arthropods available to shorebirds during their short breeding season at high latitudes. We hypothesized that prolonged exposure to warmer summer temperatures would generate earlier peaks in arthropod biomass, as well as higher peak and seasonal biomass. Across the temperature gradient encompassed by our study sites (>10°C in average summer temperatures), we found a 3-day shift in average peak date for every increment of 80 cumulative thawing degree-days. Interestingly, we found a linear relationship between temperature and arthropod biomass only below temperature thresholds. Higher temperatures were associated with higher peak and seasonal biomass below 106 and 177 cumulative thawing degree-days, respectively, between June 5 and July 15. Beyond these thresholds, no relationship was observed between temperature and arthropod biomass. Our results suggest that prolonged exposure to elevated temperatures can positively influence prey availability for some arctic birds. This positive effect could, in part, stem from changes in arthropod assemblages and may reduce the risk of trophic mismatch.

Effects of inbreeding and elevated rearing temperatures on strategic sperm investment.

Males often strategically adjust the number of available sperm based on the social context (i.e. sperm priming response), but it remains unclear how environmental and genetic factors shape this adjustment. In freshwater ecosystems, high ambient temperatures often lead to isolated pools of hotter water in which inbreeding occurs. Higher water temperatures and inbreeding can impair fish development, potentially disrupting sperm production. We used guppies (Poecilia reticulata) to investigate how developmental temperature (26 °C, 30 °C) and male inbreeding status (inbred, outbred) influence their sperm priming response. We also tested if sperm priming was affected by whether the female was a relative (sister) and whether she was inbred or outbred. There was no effect of rearing temperature; male inbreeding status alone determined the number of available sperm in response to female presence, her inbreeding status, and her relatedness. Inbred males produced significantly more sperm in the presence of an unrelated, outbred female than when no female was present. Conversely, outbred males did not alter the number of sperm available in response to female presence or relatedness. Moreover, inbred males produced marginally more sperm when exposed to an unrelated female that was outbred rather than inbred, but there was no difference when exposed to an inbred female that was unrelated versus related. Together, a sperm priming response was only observed in inbred males when exposed to an outbred female. Outbred females in our study were larger than inbred females, suggesting that inbred males strategically allocated ejaculate resources toward females in better condition.

Long-term soil warming changes the profile of primary metabolites in fine roots of Norway spruce in a temperate montane forest.

Climate warming poses major threats to temperate forests, but the response of tree root metabolism has largely remained unclear. We examined the impact of long-term soil warming (>14 years, +4°C) on the fine root metabolome across three seasons for 2 years in an old spruce forest, using a liquid chromatography-mass spectrometry platform for primary metabolite analysis. A total of 44 primary metabolites were identified in roots (19 amino acids, 12 organic acids and 13 sugars). Warming increased the concentration of total amino acids and of total sugars by 15% and 21%, respectively, but not organic acids. We found that soil warming and sampling date, along with their interaction, directly influenced the primary metabolite profiles. Specifically, in warming plots, concentrations of arginine, glycine, lysine, threonine, tryptophan, mannose, ribose, fructose, glucose and oxaloacetic acid increased by 51.4%, 19.9%, 21.5%, 19.3%, 22.1%, 23.0%, 38.0%, 40.7%, 19.8% and 16.7%, respectively. Rather than being driven by single compounds, changes in metabolite profiles reflected a general up- or downregulation of most metabolic pathway network. This emphasises the importance of metabolomics approaches in investigating root metabolic pathways and understanding the effects of climate change on tree root metabolism.

Global warming contributes to reduction in the intensity of Artemisia pollen seasons in Lublin, central-eastern Poland.

INTRODUCTION AND OBJECTIVE: Species of the genus Artemisia (Asteraceae) are weeds and ruderal plants growing in northern temperate regions of the world. Many of them are used in medicine and the cosmetic industry and for culinary purposes. Pollen grains of plants of this genus contain the most important aeroallergens. MATERIAL AND METHODS: An aerobiological study conducted with the volumetric method in Lublin in 2001-2022. Trend lines for the season parameters were established. Spearman's correlation and stepwise regression analyses were carried out to determine relationships between various parameters of the pollen season and meteorological factors. PCA analysis was also carried out to visually compare the pollen seasons. RESULTS: In Lublin, central-eastern Poland, the Artemisia pollen season lasted on average from the second ten days of July to the end of August, with its beginning depending on the temperature in April and May. The highest pollen concentrations were mainly recorded in the first half of August and were largely dependent on the mean temperature in June and July. The second peak in the pollen season recorded in September was associated with the presence of Artemisia annua pollen. Intense sunshine in June and the higher temperatures in June and July resulted in significant reduction in the Artemisia annual pollen sum (by 65%) over 22 years. Artemisia vulgaris is abundant in the Lublin region and contributes substantially to the amount of Artemisia pollen in the aeroplankton. CONCLUSIONS: The downward trend in the amount of Artemisia pollen was a result of the increase in temperatures observed in the summer months, and the declining rainfall rates. The global warming effect is extremely unfavourable for plants of Artemisia vulgaris, as they require moist soil substrates for growth.

Changes in above- versus belowground biomass distribution in permafrost regions in response to climate warming.

Permafrost regions contain approximately half of the carbon stored in land ecosystems and have warmed at least twice as much as any other biome. This warming has influenced vegetation activity, leading to changes in plant composition, physiology, and biomass storage in aboveground and belowground components, ultimately impacting ecosystem carbon balance. Yet, little is known about the causes and magnitude of long-term changes in the above- to belowground biomass ratio of plants (η). Here, we analyzed η values using 3,013 plots and 26,337 species-specific measurements across eight sites on the Tibetan Plateau from 1995 to 2021. Our analysis revealed distinct temporal trends in η for three vegetation types: a 17% increase in alpine wetlands, and a decrease of 26% and 48% in alpine meadows and alpine steppes, respectively. These trends were primarily driven by temperature-induced growth preferences rather than shifts in plant species composition. Our findings indicate that in wetter ecosystems, climate warming promotes aboveground plant growth, while in drier ecosystems, such as alpine meadows and alpine steppes, plants allocate more biomass belowground. Furthermore, we observed a threefold strengthening of the warming effect on η over the past 27 y. Soil moisture was found to modulate the sensitivity of η to soil temperature in alpine meadows and alpine steppes, but not in alpine wetlands. Our results contribute to a better understanding of the processes driving the response of biomass distribution to climate warming, which is crucial for predicting the future carbon trajectory of permafrost ecosystems and climate feedback.

A dynamic energy budget (DEB) model to assess the sublethal effects of imidacloprid toward Gammarus pulex at different temperatures.

Environmental ambient temperature significantly impacts the metabolic activities of aquatic ectotherm organisms and influences the fate of various chemicals. Although numerous studies have shown that the acute lethal toxicity of most chemicals increases with increasing temperature, the impact of temperature on chronic effects - encompassing both lethal and sublethal endpoints - has received limited attention. Furthermore, the mechanisms linking temperature and toxicity, potentially unveiled by toxicokinetic-toxicodynamic models (TKTD), remains inadequately explored. This study investigated the effects of environmentally relevant concentrations of the insecticide imidacloprid (IMI) on the growth and survival of the freshwater amphipod Gammarus pulex at two different temperatures. Our experimental design was tailored to fit a TKTD model, specifically the Dynamic Energy Budget (DEB) model. We conducted experiments spanning three and six months, utilizing small G. pulex juveniles. We observed effects endpoints at least five times, employing both destructive and non-destructive methods, crucial for accurate model fittings. Our findings reveal that IMI at environmental concentrations (up to 0.3 µg/L) affects the growth and survival of G. pulex, albeit with limited effects, showing a 10% inhibition compared to the control group. These limited effects, observed in both lethal and sublethal aspects, suggest a different mode of action at low, environmentally-relevant concentrations in long-term exposure (3 months), in contrast to previous studies which applied higher concentrations and found that sublethal effects occurred at significantly lower levels than lethal effects in an acute test setting (4 days). Moreover, after parameterizing the DEB model for various temperatures, we identified a lower threshold for both lethal and sublethal effects at higher temperatures, indicating increased intrinsic sensitivity. Overall, this study contributes to future risk assessments considering temperature as a crucial factor and exemplifies the integration of the DEB model into experimental design for comprehensive toxicity evaluations.

Bacterial abundant taxa exhibit stronger environmental adaption than rare taxa in the Arctic Ocean sediments.

Marine bacteria influence Earth's environmental dynamics in fundamental ways by controlling the biogeochemistry and productivity of the oceans. However, little is known about the survival strategies of their abundant and rare taxa, especially in polar marine environments. Here, bacterial environmental adaptation, community assembly processes, and co-occurrence patterns between abundant and rare taxa were compared in the Arctic Ocean sediments. Results indicated that the diversity of rare taxa is significantly higher than that of abundant taxa, whereas the distance-decay rate of rare taxa community similarity is over 1.5 times higher than that of abundant taxa. Furthermore, abundant taxa exhibited broader environmental breadth and stronger phylogenetic signals compared to rare taxa. Additionally, the community assembly processes of the abundant taxa were predominantly governed by 81% dispersal limitation, while rare taxa were primarily influenced by 48% heterogeneous selection. The co-occurrence network further revealed the abundant taxa formed a more complex network to enhance their environmental adaptability. This study revealed the differences in environmental responses and community assembly processes between bacterial abundant and rare taxa in polar ocean sediments, providing some valuable insights for understanding their environmental adaptation strategies in marine ecosystems.