Current Climate Research Articles

Phytoclimatological study in the high plains of Sétif: application of the bioclimatic classification system (Algeria)

The Global Bioclimatic Classification System (WBCS) by Rivas-Martínez is an effective approach to reflect and study the role of climate in determining the potential distribution of natural vegetation at various temporal and spatial scales. In particular, the diversity of physical characteristics in the Setifian high plains leads to the complexity of large-scale phytogeographic belts. Isobioclimates, unique combinations of bioclimatic indices (continentality, ombrotype, and thermotype), have been created for the study area based on Rivas-Martínez's global bioclimatic classification system for current and future climate scenarios, using the parallel climate model from CMIP5 (Coupled Model Intercomparison Project) under the intermediate greenhouse gas emission scenario (RCP4.5). Precipitation and temperature data from the "WorldClim" dataset were used as the data source. These climatic variables were reduced to a spatial resolution of 1 km. The objective is to understand how the climate is evolving in this region, what the consequences are, and what the future holds for these natural ecosystems. A phytosociological study complemented by satellite image analysis reveals a high diversity of pre-forestry formations. The digitally mapped results were used to 1) assess the relative redistribution of isobioclimates and the magnitude of change, 2) identify and locate the new projected isobioclimates, and 3) explore the compositional changes in vegetation types among analogous isobioclimatic zones. The ordination of the relationships between vegetation and bioclimates shows a strong correlation between Rivas-Martinez indices and the distribution and composition of vegetation. Changes in ombrotype, thermotype, bioclimate, ombrotype, and isobioclimate differed between the current and future series. The resulting map presents 9 isobioclimatic units, which are advantageous for confirming the diagnosis of bioclimatic characteristics and describing the relationships between climatic variables and the corresponding distributions of natural vegetation. We identified eight different isobioclimates for the current period (1979-2013) and seven for the future period (2050), three thermotype horizons for both the current and future periods, and finally, four ombrotype horizons for the period (1979-2013), while two ombrohorizons represent the period (2050). This approach is useful for explaining territorial diversity in environmental applications related to ecological adaptation assessment, nature conservation, landscape regionalization, and planning.

The Asian Citrus Psyllid (<i>Diaphorina citri</i>) in Africa: using MaxEnt to predict current and future climatic suitability, with a focus on potential invasion routes

The Asian Citrus Psyllid (ACP) (Diaphorina citri Kuwayama, 1908) (Hemiptera: Psyllidae) is a major citrus pest. The species has been introduced to West and East Africa, but has not yet spread to southern Africa, where it could have a devastating impact on citrus farming and livelihoods. A proactive response is key to mitigating the species’ impacts, particularly the ongoing monitoring of potential invasion routes and entry points into South Africa. Species distribution models (SDMs) were developed under current and future climates for ACP in Africa, and these models were used to (1) determine where the species likely poses a threat, (2) identify potential invasion routes into South Africa, and (3) assess how these factors will be affected under climate change. The SDMs indicated that there is an almost contiguous band of suitable climate along the east coast of Africa that joins the species’ current range in East Africa to South Africa, and under aggressive climate change a potential route of invasion through Namibia and Botswana. Much of South Africa is climatically suitable for the species, but under climate change, climatically suitable areas are likely to shift further inland. The spread of ACP into South Africa is unlikely to be prevented, but the outputs of the present models will inform monitoring activities and assist with preparations to respond to this predicted biological invasion.

The Asian Citrus Psyllid (<i>Diaphorina citri</i>) in Africa: using MaxEnt to predict current and future climatic suitability, with a focus on potential invasion routes

The Asian Citrus Psyllid (ACP) (Diaphorina citri Kuwayama, 1908) (Hemiptera: Psyllidae) is a major citrus pest. The species has been introduced to West and East Africa, but has not yet spread to southern Africa, where it could have a devastating impact on citrus farming and livelihoods. A proactive response is key to mitigating the species’ impacts, particularly the ongoing monitoring of potential invasion routes and entry points into South Africa. Species distribution models (SDMs) were developed under current and future climates for ACP in Africa, and these models were used to (1) determine where the species likely poses a threat, (2) identify potential invasion routes into South Africa, and (3) assess how these factors will be affected under climate change. The SDMs indicated that there is an almost contiguous band of suitable climate along the east coast of Africa that joins the species’ current range in East Africa to South Africa, and under aggressive climate change a potential route of invasion through Namibia and Botswana. Much of South Africa is climatically suitable for the species, but under climate change, climatically suitable areas are likely to shift further inland. The spread of ACP into South Africa is unlikely to be prevented, but the outputs of the present models will inform monitoring activities and assist with preparations to respond to this predicted biological invasion.

Buzzing towards Resilience: Investigating the Spatial Alignment of the Desert Pallid Bee, Centris pallida, and Its Host Plants in Response to Climate Change.

Wild bees are vital for the pollination of native plants and crops, providing essential ecosystem services. Climate change is known to impact biodiversity and species distributions, but insects adapted to desert ecosystems may exhibit unique physiological, behavioral, and evolutionary responses. The desert pallid bee (C. pallida), a solitary bee native to the arid southwestern United States and northern Mexico, primarily forages on yellow palo verde (P. microphylla), blue palo verde (P. florida), and desert ironwood (O. tesota). This study used MaxEnt to estimate the current and projected geographical overlap of suitable habitats for C. pallida and its host plants. Here, we used MaxEnt to estimate the current and forecasted overlapping geographically suitable habitat of C. pallida with all three host plants. We forecasted potential environmentally suitable areas for each species to the year 2040 using the current distribution model and climate projections with moderate CO2 levels. We found a continued spatial alignment in the suitable area of the bee and its host plants with a 70% increase in the range overlap area, though shifted to higher average altitudes and a slight northern expansion. These findings may provide insight to stakeholders on the conservation needs of desert-dwelling pollinators.

Conserved responses of water use to evaporative demand in mixed forest across seasons in low subtropical China

The positive correlation between diversity and production has been extensively documented. Given the intrinsic relationship between production and plant water consumption, it was anticipated that mixed forests would exhibit different water use compared to pure forests. In this study, the responses of water use to vapour pressure deficit were analyzed by monitoring the sap flow of Schima superba in both pure and mixed forests, as well as Castanopsis chinensis in mixed forest. Additionally, the relationships among leaf and stem traits were examined by measuring specific leaf area (SLA), N and P concentration per unit leaf mass, leaf δ18O and δ13C and wood density of sapwood (WD) during both wet and dry seasons. The results showed that S. superba demonstrated a comparable regulation of water use during both wet and dry seasons in mixed forest, whereas it exhibited less strict water use regulation during the wet season in comparison to the dry season in pure forest. Regardless of whether the forests were pure or mixed, both leaf δ13C and WD remained consistent across seasons, while there was an increase in SLA during the wet season compared to the dry season for S. superba. There was a different seasonal change in leaf δ18O for S. superba in pure and mixed forests. Water use and leaf economic spectrum may determine the adaptive strategies of coexisting species, and the coexisting tree species in mixed forest exhibited a resource-use differentiation, as indicated by seasonal variations in leaf and stem traits, likely explaining the conserved responses of sap flow to evaporative demand. Our research might provide insights into the impact of tree interaction on water use strategies and the water use-based forest management under current climate change.

Application of coupled MIKE SHE/MIKE HYDRO on streamflow dynamics under climate change in Lake Tana sub basin, Abay Basin, Ethiopia

AbstractWater availability and quality are fluctuating due to climate change, which has disastrous effects on life. Modeling climate change impact on streamflow in the Lake Tana sub‐basin (LTSB) in selected watersheds was the main goal of the research. This research is unique in that it applies the coupled MIKE SHE/MIKE HYDRO model technique, which has not been applied before to investigate changes in streamflow due to climate change in LTSB. Streamflow in the LTSB was forecasted using the MIKE SHE/MIKE HYDRO model from seven ensembles of GCMs under two emission scenarios (SSP2–4.5 and SSP5–8.5) between 2041 and 2,100. According to the calibration and validation results in the period of 1985–2007, MIKE SHE performs well while simulating streamflow in LTSB. During calibration and validation, the Nash‐Sutcliffe efficiency (NSE) values in all watersheds were greater than 0.8, except for the Ribb watershed calibration, where it was 0.75. The mean monthly changes in temperatures indicate an incremental tendency in the next decades. According to the simulation result, the monthly mean rainfall for SSP2–4.5 and SSP5–8.5 will increase from 0.05 to 61.9% and 2.02 to 46.26% in the 2050s and 8.7 to 44.38% to 6.44 to 66.24% in the 2080s, respectively. Gilgle Abay, Gumara, and Ribb watersheds will lose 56.2, 56.65, 57.01% of their mean monthly streamflow in the 2050s, according to SSP2–4.5. For the Gilgle Abay, Gumara, and Ribb watersheds, streamflow will increase by 6.7% to 21.94%, 6.08% to 23.26%, and 6.51% to 22.88%, accordingly, in the 2050s under SSP5–8.5. Increased rainfall in the watershed could result in floods in the already‐flooded Gumara and Ribb flood plains. The government and community should implement coping mechanisms to lessen the impact of climate change like early warring and planting more trees. Overall, the study showed that it is expected that conditions related to streamflow may change in the future due to climate alteration. By offering a better understanding of current and future climates, the integrated modeling system developed can assist environmentalists, hydrologists, and policymakers in water management and policy intervention.

The Portofino Promontory: 200 Years of History of Marine Biology

This paper outlines the history of scientific research developed in the Portofino Promontory, located in the centre of the Ligurian Sea. The chronicles span over two centuries, from the late 18th century to the present day. Portofino is now recognised as one of the best-known areas in the world regarding marine biological communities and their temporal dynamics, particularly in relation to current climate changes. In addition, since 1999, with the establishment of the Marine Protected Area, significant research related to marine environment conservation has developed in Portofino. The role of the University of Genoa, the Natural History Museum, other important institutions, and the researchers involved in the Portofino area has been outlined.

Protecting subterranean ecosystems for the wellbeing of surface environments and humanity

Protecting subterranean ecosystems for the wellbeing of surface environments and humanity Stefano Mammola, a researcher at the Italian National Research Council and coordinator of the Biodiversa+ project ‘DarCo’, emphasizes the importance of better incorporation of subterranean biodiversity in conservation agendas. Beneath our feet lies a vast and intricate network of caves, aquifers, fissures, and other voids teeming with unique life forms crucial to both human life and the environment. Groundwaters, for instance, represent the largest unfrozen freshwater reserve, serving as the primary water source for over half of the world’s population. Despite their importance, subterranean ecosystems receive minimal attention in current biodiversity and climate change agendas – a concerning oversight that demands urgent action. (1)

Reptile Diversity Patterns Under Climate and Land Use Change Scenarios in a Subtropical Montane Landscape in Mexico

ABSTRACTAimMountainous regions are rich in reptile biodiversity but face threats from climate and land use changes. Understanding how these factors affect reptile diversity in these regions can highlight key conservation hotspots that require effective conservation actions. Here, we explored reptile taxonomic and functional diversity patterns along the Sierra Madre del Sur region in southeast Mexico, and potential changes in future years caused by different climate and land use change scenarios.LocationSierra Madre del Sur, México.TaxonReptiles.MethodsWe used species distribution models and information on species traits to estimate taxonomic and functional diversity throughout the Sierra Madre del Sur (SMS) region under current and future climate and land use change scenarios.ResultsGreater taxonomic and functional diversity was observed in both temperate and tropical forests. Taxonomic diversity was higher in more drier areas at high elevations while higher functional diversity was observed in wetter areas at intermediate‐to‐high elevations. Lower diversity for both dimensions was associated with anthropic land uses. In future scenarios, both dimensions of diversity are expected to increase in temperate forest in highlands of central Oaxaca and decrease in the southcentral portion of the SMS, particularly for the worst scenarios due to increased deforestation rates.Main ConclusionsHigher taxonomic diversity in more drier areas at high elevations could be due to historical and evolutionary factors, while higher functional diversity in wetter areas at intermediate‐to‐high elevations may be explained by a higher environmental heterogeneity in forests within these conditions. Larger diversity losses in the southcentral portion of the SMS are probably due to larger predicted deforestation rates in those areas. Our results are valuable not just for informing conservation actions, such as the creation of protected natural areas but also to understand the underlying processes behind the patterns of reptile diversity.

Reexploring Rice Germplasm: Enlightening a New Path Towards Abiotic Stress-resilient Crop

Oryza sativa, the commonly cultivated rice, is one of the most important crops for human consumption, but is also a crop whose production system is increasingly threatened by the current climate changes. Due to its intensive water requirement rice faces a lot of challenges due to abiotic stresses like drought, heat stress, salinity, flooding etc. Drought is the major abiotic stress to rice grain production under unpredictable and changing environmental conditions. Traits supporting drought resistance are limited in cultivars, while wild rice species like O. glaberrima, O. longistaminata, O. rufipogon and O. meridonalis represent an important reservoir of useful genes for this trait which can be exploited to develop varieties tolerant to drought. Similarly O. australiensis, O. coarctata and O. rufipogon serve as an important sources for salinity-tolerant genes. O. rufipogon, O. meridonalis, O. australiensis comprise a collection of accessions that are reservoirs for heat-tolerant genes. Although many efforts have resulted in breeding rice varieties that are relatively tolerant to their local environments; climate change and population growth are expected to soon require a new, rapid generation of stress-tolerant rice germplasm. Diversity studies suggest that the current diversity within rice varieties may not be sufficient for generation of highly resistant or tolerant varieties for the unfavorable growing conditions. All the efforts to design an ideotype to increase production and productivity has been attempted previously, rice self-sufficiency can be attained only if high production and productivity is coupled with a high degree of tolerance and resistance to biotic and abiotic stress factors. Since it has been found that wild rice relatives serve as a hub for many desirable genes conferring tolerance or resistance to specific stresses, the present article is focused on provide an overview of different wild ancestors of rice which can be exploited to identify suitable donors for gene of interest, their ecological and genomic diversity and the variation observed in wild Oryza species for different stress tolerance traits. Such identified traits can be incorporated in modern day breeding programmes through marker assisted breeding to develop cultivable varieties with desired tolerance to abiotic stresses or transfer such traits to modern day cultivars through backcross breeding.

Automatic Detection and Identification of Calcareous Nannofossils in Chalk Using Deep Learning: A Proof-of-Concept Study for Biostratigraphy and Climate Research

Calcareous nannofossils serve as crucial indicators for establishing the biostratigraphic age of chalk macrofossil specimens in natural science collections. Better age control of specimens collected several hundred years ago enables us to uncover the dark data hidden within these collections and incorporate these data into current research projects, examining ecosystem response to past climate change. However, the manual identification of these microscopic organisms is laborious and subjective, and so we are harnessing deep learning techniques for automatic nannofossil detection and identification. This approach required the construction of a robust dataset, currently comprising over 100,000 labelled images, complemented by the development of multiple specialised deep learning models. While some models focus on detecting target species, others are dedicated to species classification. Evaluation on an independent test set showcases the efficacy of our methodology, with the current detection model achieving a balanced accuracy of 93%. Similarly, the classification model demonstrates robust performance, attaining an average balanced accuracy of 96%. Furthermore, as well as assisting with our biostratigraphic studies, the dataset of accurately labelled images has enabled us to test other aspects of ecosystem response. For example, examining morphometric changes in nannofossils over geological time can provide valuable insights into the potential impact of current global warming on modern phytoplankton assemblages (Mancini et al. 2021). This is particularly important for coccolithophores (Young et al. 2005), which play a critical role as primary producers in the global carbon cycle. A decrease in their size could lead to bottom-up ecosystem impacts and reduced carbon sequestration (Poulton et al. 2007, Krumhardt et al. 2017). Using our dataset, we conducted a deep-learning-enhanced automatic morphometric analysis focusing on the nannofossil species, Tranolithus orionatus. Our analysis revealed that two key morphometric parameters, minor axis and area size, showed statistically significant differences between the Cenomanian stage (approximately 100.5 to 93.9 million years ago) and the post-Cenomanian stages of the Late Cretaceous (approximately 93.9 to 66.0 million years ago). Kolmogorov-Smirnov tests (Massey 1951) between the two samples yielded p-values of 0.039 for the minor axis and 0.031 for the area size. Understanding these morphometric changes is crucial due to the close parallels between current climate projections and the warming and greenhouse climate of the Late Cretaceous, particularly the Cenomanian-Turonian boundary event (Arthur et al. 1990). Insights into how organisms changed morphologically during past periods of environmental stress can help us more effectively predict future responses of organisms under similar conditions (Razmjooei et al. 2020). These findings underscore the effectiveness of our approach in automating the identification and recognition of chalk nannofossils, helping to unlock natural science collections and to address key questions related to marine response to past climate change.

Exploring the material-discursive relations in literacies and language instruction: A state-wide view of binary logics at work

ABSTRACT This article discusses the current Missouri (U.S.) socio-political landscape of literacies and language education pedagogies across PreK-12 settings. Specifically, our research focus explores the binaries that educators in schools experience which a/effects material-discursive relations of literacy teaching and learning. We understand how literacy education policies, initiatives, and practices as well as socio-political climate can produce unique conditions that shape schooling and how many of these can impact learning and teaching conditions as generative and/or paralysing spaces for educators and their students. We conceptualize pedagogies through material-discursive philosophies that shift away from humanist logics and present our research inquiry to foreground the conditions that produce our current U.S. literacy landscape. This paper draws on state-wide data from 1,550 surveys and 113 interviews with PreK-12 teachers. We employ two theoretical concepts as analytical tools: thresholding and eventicizing. These tools help us to explore how teaching and learning are dynamic constellations of material-discursive relations that put the current socio-political literacy education climate in conversation with the materials and texts teachers select and share. We discuss what is produced within these material-discursive binary conditions noticing how teachers resist and persist within the binaried worlds they find themselves in as educators.

Maxent modelling reveals suitable habitat remains unchanged for Carcinus maenas in Australia

ABSTRACT This study assesses the habitat suitability of the invasive green crab, Carcinus maenas, in Australia using MaxEnt modelling under current and future climate scenarios. The species has significant ecological impacts, displacing native species and altering habitats. Using 90 occurrence points from the Global Biodiversity Information Facility, the MaxEnt model shows high performance (Area Under the Curve value of 0.99), indicating reliable predictions. Currently, the green crab's habitat suitability along the Australian coast ranges from high to medium in Tasmania, Victoria, New South Wales and South Australia and low in Western Australia and South Queensland. Future projections suggest a decrease in suitable habitats, confined to Tasmania, Victoria, Adelaide and New South Wales. These findings can guide the development of long-term management and conservation plans for C. maenas, with an emphasis on areas with consistent habitat suitability. Additionally, further field and laboratory experiments are recommended to understand the species’ tolerance to environmental changes. Recognising the ecological impact of C. maenas is crucial for informed decision-making to preserve Australia's ecosystems and ensure the sustainable coexistence of native species amidst invasive threats.

Current climate action trends in party‐political manifestos: A content analysis provides hints to move forward

AbstractParty manifestos offer valuable insights into evolving climate political agendas, warranting relevant content to understand parties' priorities and approaches to climate resilience. Through a content analysis of Portuguese party manifestos from the 2019, 2022, and 2024 elections, this study aims to address key research questions regarding SDG 13 targets. The results demonstrate a positive trend within SDG 13, albeit predominantly focused on targets 13.1 and 13.2. Left‐wing parties exhibit stronger commitment compared to their right‐wing counterparts, with variations observed based on European affiliations. Across all SDG 13 targets, left‐wing party manifestos consistently covered a broader spectrum of themes compared to their right‐wing counterparts. Green parties exhibit a partial higher commitment relative to the dominant governance parties in Portugal, which is recently governed by a right‐wing coalition. Findings aim to inform and potentiate refinement of climate policy agendas, contributing to future sustainability initiatives in Portugal and beyond.

Projected Antarctic sea ice change contributes to increased occurrence of strong El Niño

Current climate models suggested that Antarctic sea ice cover would decrease substantially under cumulative CO2 emission, but little is known whether large decrease in Antarctic sea ice can influence the occurrence of strong El Niño. Using time slice coupled and uncoupled model experiments, we show that in response to half reduction of Antarctic sea ice projected near the end of the 21st century, the frequency of strong El Niño would be increased by ~40%. It is contributed by enhanced thermocline, Ekman, and zonal advective positive feedbacks that are partly offset by enhanced thermodynamic damping. The strong warming and weakened westerly winds in the southeastern Pacific generate an anomalous Rossby wave propagating into the eastern subtropical and tropical Pacific, favoring stronger El Nino, and air-sea coupling and ocean feedbacks play a critical role in the teleconnection. Unexpectedly, compare to halved Antarctic sea ice, the ice-free Antarctic leads to a decrease in the frequency of strong El Niño, which is largely due to a substantial increase in thermodynamic damping. We also show that a large portion of the increase of strong El Niño events under greenhouse warming might be connected with Antarctic sea-ice loss, though increased greenhouse gas plays an important role.

Active Sites for CO2 Hydrogenation to Methanol: Mechanistic Insights and Reaction Control.

Catalytic CO2 conversion to methanol is a promising way to extenuate the adverse effects of CO2 emission, global warming and energy shortage. Understanding the fundamental features of CO2 activation and hydrogenation at the molecular level is essential for carbon utilization and sustainable chemical production in the current climate crisis. This review explores the recent advances in understanding the design of catalysts with desired active sites, including single-atom, dual-atom, interface, defects/vacancies and promoters/dopants. We focused on the design of various catalytic systems to enhance their catalytic performances by stabilizing active metal in a catalyst, identifying the unique structure of active species, and engineering coordination environments of active sites. Mechanistic insights provided by advanced operando and in situ spectroscopies were also discussed. Moreover, the review highlights the key factors affecting active sites and reaction mechanisms, such as local environments, oxidation states, and metal-support interactions. By integrating recent advancements and relating knowledge gaps this review aims to endow an inclusive overview of the field and guide future research toward more efficient and selective catalysts for CO2 hydrogenation to methanol.

Social Cost of Carbon as an International Benchmark to Drive Countries’ Carbon Pricing during the Transition

Building on updated estimates of the social cost of carbon obtained from the most recent literature, this article proposes a social cost of carbon-based benchmark for carbon pricing to drive world countries’ carbon pricing policies up to 2050, consistent with the Paris Agreement targets. By using a dataset on net effective carbon rates developed by the Organisation for Economic Co-operation and Development (OECD), we firstly compare both explicit and implicit carbon pricing in 2021 in 71 OECD and non-OECD countries with the social cost of carbon benchmark for 2021 and calculate the degree of internalization of the social cost of carbon averagely related to their carbon pricing instruments. We find that there is a serious gap in current climate policies, which are far from creating optimal pricing conditions to reduce global emissions to levels needed by the Paris Agreement. The economic and distributional feasibility of a full implementation of the carbon pricing benchmark is tested in the same set of countries using two indicators, which are calculated for 2025, 2030, 2040 and 2050. Since the test results are income-regressive among income country groups, benchmark implementation by countries within the cooperative approaches of Paris Agreement art. 6 should be accompanied by the creation of an international cooperative fund aimed to recycle at least part of the revenues collected by high-income countries to compensate affected population in lower-income countries.

Future Change in the Contribution of Riming and Depositional Growth to the Surface Solid Precipitation in Hokkaido, Japan

Abstract This study examined future changes in the microphysical properties of surface solid precipitation over Hokkaido, Japan. A process-tracking model that predicts the mass of the hydrometeors generated by each cloud microphysical process was implemented in a meteorological model. This implementation aimed to analyze the mass fraction of hydrometeors resulting from depositional growth and the riming process to the total mass of surface solid precipitation. Results from pseudo–global warming experiments suggest two potential future changes in the characteristics of surface solid precipitation over Hokkaido. First, the rimed particles are expected to increase and be dominant over the west and northwest coast of Hokkaido, where heavy snowfall occurs primarily due to the lake effect. Second, the mass fraction from depositional growth under relatively higher temperatures is expected to increase. This increase is anticipated to be dominant over the eastern part and mountainous area of Hokkaido. Additionally, the fraction of liquid precipitation to total precipitation is expected to increase in the future. These results suggest that the microphysical properties of solid precipitation in Hokkaido are expected to be similar to those observed in the current climate over Hokuriku, the central part of Japan even in warmer climate conditions. Significance Statement This study examines potential future changes in the growth processes contributing to surface precipitation particles in Hokkaido, Japan. The surface solid precipitation particles in the western and eastern regions of Hokkaido are mainly generated through depositional growth that occurs within the temperature ranges −36° to −20°C and −20° to −10°C, respectively. A future shift is anticipated, with riming becoming the primary process. This shift suggests that snowfall particles will be heavier than those in the current climate, which would increase the snow-removal workload. The change in precipitation characteristics could influence adaptation and mitigation strategies for climate change in cold regions.

Trends and Drivers of Water Temperature Extremes in Mountain Rivers

AbstractWater temperature extremes can pose serious threats to the aquatic ecosystems of mountain rivers. These rivers are influenced by snow and glaciermelt, which change with climate. As a result, the frequency and severity of water temperature extremes may change. While previous studies have documented changes in non‐extreme water temperature, it is yet unclear how extreme water temperatures change in a warming climate and how their hydro‐meteorological drivers differ from those of non‐extremes. This study aims to assess temporal changes and spatial variability in water temperature extremes and enhance our understanding of the driving processes across European mountain rivers in the current climate, at both a regional and continental scale. First, we describe the characteristics of extreme events and explore their relationships with catchment characteristics. Second, we assess trends in water temperature extremes and compare them with trends in mean water temperature. Third, we use random forest models to identify the main driving processes of water temperature extremes. Last, we conduct a co‐occurrence analysis to examine the relationship between water temperature extremes and hydro‐climatic extremes. Our results show that mean water temperature has increased by °C per decade, leading to more extreme events at high elevations in spring and summer. While non‐extreme water temperatures are mainly driven by air temperature, water temperature extremes are also importantly influenced by soil moisture, baseflow, and meltwater. Our study highlights the complexity of water temperature dynamics in mountain rivers at the regional and continental scale, especially during water temperature extremes.

Preventing Bleaching in Tropical Corals by Using Thermally Resilient Symbiont Zooxanthellae: All Hands‐On Deck!

ABSTRACTThe current rapid climate warming is expected to cause an ocean temperature increase of 3°C–5°C by 2100, leading to deoxygenated and acidified tropical seas. Without mitigation measures, the total loss of tropical corals is inevitable. Already, one‐third of tropical reefs are considered permanently lost. Coral bleaching initiated by the loss of symbionts, the photosynthetic zooxanthellae, is the main process whereby corals respond to thermal stress, followed by recovery. However, increased thermal stress and frequency of bleaching have caused widespread coral recovery failure. Zooxantheallae of the genus Symbiodinium are considered the thermally vulnerable part of the coral symbiosis. In recent decades, warming has displaced genotypes of lower thermal resilience to subtropical latitudes; few genotypes of higher temperature tolerance remain abundant in tropical seas, but these will not withstand warming predictions either. Interestingly, high temperatures in the Red Sea have selected for exceptionally heat‐resistant coral genotypes and for the highest known thermal resilience in endemic zooxanthellae at the same time. Actions to overcome the coral bleaching crisis have been proposed by combining coral ecophysiology and mass culturing of thermally resilient Red Sea symbionts for naturalisation to the global tropical ocean, including restoration of collapsed reefs using corals with thermally resilient symbiont genotypes.