Search Results (175)

Due to global warming, extreme temperature events have become increasingly prevalent, posing significant threats to both socioeconomic development and human safety. While previous studies have extensively examined the influence of individual climatic circulation systems on extreme temperature, the combined effects of multiple concurrent circulation patterns remain poorly understood. Using daily temperature data from 29 meteorological stations in Chongqing (1960–2019), this study employs linear trend analysis, correlation analysis, and random forest (RF) models to analyze spatiotemporal variations in the intensity and frequency of extreme temperature. We selected 21 climate indicators from three categories—atmospheric circulation, sea surface temperature (SST), and sea-level pressure (SLP)—to identify the primary drivers of extreme temperatures and quantify their respective contributions. The key findings are as follows: (1) All extreme intensity indices exhibited an increasing trend, with the TXx (annual maximum daily maximum temperature) showing the higher trend (0.03 °C/year). The northeastern region experienced the most pronounced increases. (2) Frequency indices also displayed an upward trend. This was particularly evident for the TD35 (number of days with maximum temperature ≥35 °C), which increased at an average rate of 0.16 days/year, most notably in the northeast. (3) The Western Pacific Subtropical High Ridge Position Index (GX) and Asia Polar Vortex Area Index (APV) were the dominant climate factors driving intensity indices, with cumulative contributions of 26.0% to 33.4%, while the Western Pacific Warm Pool Strength Index (WPWPS), Asia Polar Vortex Area Index (APV), North Atlantic Subtropical High Intensity Index (NASH), and Indian Ocean Warm Pool Strength Index (IOWP) were the dominant climate factors influencing frequency indices, with cumulative contributions of 46.4 to 49.5%. The explanatory power of these indices varies spatially across stations, and the RF model effectively identifies key circulation factors at each station. In the future, more attention should be paid to urban planning adaptations, particularly green infrastructure and land use optimization, along with targeted heat mitigation strategies, such as early warning systems and public health interventions, to strengthen urban resilience against escalating extreme temperatures. Full article

Protecting threatened elasmobranch species despite limited data on their distribution and abundance is a critical challenge, particularly in the context of increasing human impacts on marine ecosystems. In the northeastern Atlantic, species such as the leafscale gulper shark, Portuguese dogfish, spurdog, and spotted ray are facing pressures from overfishing, bycatch, habitat degradation, and climate change. The OSPAR Commission has listed these species as threatened and/or declining and aims to protect them by reliably identifying suitable habitats and integrating these areas into Marine Protected Areas (MPAs). In this study, we present a spatial modelling framework using regression-based approaches to identify suitable habitats for these four species. Results show that suitable habitats of the spotted ray (25.8%) and spurdog (18.8%) are relatively well represented within existing MPAs, while those of the deep-water sharks are underrepresented (6.0% for leafscale gulper shark, and 6.8% for Portuguese dogfish). Our findings highlight the need for additional MPAs in deep-sea continental slope areas, particularly west and northwest of Scotland and Ireland. Such expansions would support OSPAR’s goal to protect 30% of its maritime area by 2030 and could benefit broader deep-sea biodiversity, including other vulnerable demersal species and benthic communities. Full article

This study presented a comprehensive physical–statistical analysis of atmospheric particulate matter (PM₁₀ and PM_2.5) and trace gases (SO₂ and O₃) over Faial Island in the Azores archipelago during 2024. We collected real-time data at the Espalhafatos rural background station, covering 35,137 observations per pollutant, with 15 min intervals. Descriptive statistics, probability distribution fitting (Normal, Lognormal, Weibull, Gamma), and correlation analyses were employed to characterize pollutant dynamics and identify extreme pollution episodes. The results revealed that PM_2.5 (fine particles) concentrations are best modeled by a Lognormal distribution, while PM₁₀ concentrations fit a Gamma distribution, highlighting the presence of heavy-tailed, positively skewed behavior in both cases. Seasonal and episodic variability was significant, with multiple Saharan dust transport events contributing to PM exceedances, particularly during winter and spring months. These events, confirmed by CAMS and SKIRON dust dispersion models, affected not only southern Europe but also the Northeast Atlantic, including the Azores region. Weak to moderate correlations were observed between PM concentrations and meteorological variables, indicating complex interactions influenced by atmospheric stability and long-range transport processes. Linear regression analyses between SO₂ and O₃, and between SO₂ and PM_2.5, showed statistically significant but low-explanatory relationships, suggesting that other meteorological and chemical factors play a dominant role. This result highlights the importance of developing air quality policies that address both local emissions and long-range transport phenomena. They support the implementation of early warning systems and health risk assessments based on probabilistic modeling of particulate matter concentrations, even in remote Atlantic locations such as the Azores. Full article

Background/Objectives: The overuse and misuse of antibiotics has contributed significatively to the growing problem of the emergence and spread of antibiotic resistance genes among bacteria, posing a serious global challenge to the treatment of bacterial infectious diseases. For these reasons, there is a current and growing interest in the development of effective alternative or complementary strategies to antibiotic therapy for the prevention of fish diseases, which are mainly based on the use of probiotics—in particular, those belonging to the Lactic Acid Bacteria (LAB) group. In this context, the aim of the present study was to characterise, evaluate the genetic diversity and assess the safety of candidate probiotic LAB strains for aquaculture isolated from faeces and intestines of European hakes (Merluccius merluccius, L.) caught in the Northeast Atlantic Ocean (Ireland). Methods: The direct antimicrobial activity of the LAB isolates was tested by the Stab-On-Agar method against key ichthyopathogens. Subsequently, their taxonomic classification and genetic diversity were determined by 16SrDNA sequencing and Enterobacterial Repetitive Intergenic Consensus-PCR (ERIC-PCR), respectively. To ensure the in vitro safety of the LAB isolates, their biofilm-forming ability was assessed by a microtiter plate assay; their sensitivity to major antibiotics used in aquaculture, human and veterinary medicine by a broth microdilution method and their haemolytic and gelatinase activity by microbiological assays. Results: All LAB isolates were biofilm producers and susceptible to chloramphenicol, oxytetracycline, flumequine and amoxicillin. A total of 30 isolates (85.7%) were resistant to at least one of the tested antibiotics. None of the 35 LAB isolates showed haemolytic or proteolytic activity. Conclusions: Among the isolated strains, five LAB strains exhibiting the highest antimicrobial activity against aquaculture-relevant ichthyopathogens, taxonomically identified as Streptococcus salivarius, Enterococcus avium and Latilactobacillus sakei, were selected for further characterisation as potential probiotic candidates to promote sustainable aquaculture. To our knowledge, this is the first study to report that hake intestines and faeces represent viable ecological niches for the isolation of LAB strains with antimicrobial activity. Full article

Long-term continuous and reliable real-time ocean wave height data are important for climatologists, offshore industries, leisure craft users, and marine forecasters. However, maintaining data continuity and reliability is challenging due to offshore equipment failures and sparse in situ observations. Opposing interactions between wind-driven ocean waves generate acoustic waves near the ocean surface, which can convert to seismic waves at the seafloor and travel through the Earth’s solid structure. These low-frequency seismic waves, known as secondary microseisms, are clearly recorded on terrestrial seismometers offering land-based access to ocean wave states via seismic ground vibrations. Here, we demonstrate the potential of this by estimating ocean Significant Wave Heights (SWHs) in the Northeast Atlantic using continuous recordings from a land-based seismic network in Ireland. Our method involves connecting secondary microseism amplitudes with the ocean waves that generate them, using an Artificial Neural Network (ANN) to quantify the relationship. Time series data of secondary microseism amplitudes together with buoy-derived and numerical model ocean significant wave heights are used to train and test the ANN. Application of the ANN to previously unseen data yields SWH estimates that closely match in situ buoy observations, located approximately 200 km offshore, Northwest of Ireland. Terrestrial seismic data are relatively cheap to acquire, with reliable weather-independent data streams. This suggests a pathway to a complementary, exceptionally cost-effective, data-driven approach for future operational applications in real-time SWH determination. Full article

This study aimed to identify Leishmania species in small non-flying mammals captured in semi-deciduous forest fragments of the Atlantic Forest and pastures in the Southwest region of Bahia state, Northeast Brazil. A total of 445 animals belonging to 11 different species were captured, the majority being rodents (75.7%; 337), followed by marsupials (24.2%; 108), and the most prevalent species were Cerradomys vivoi, Calomys expulsus, Necromys Lasiurus, and Marmosops incanus. Liver, spleen, kidney, heart, and lung fragments were collected for subsequent molecular diagnosis. Leishmania spp. kDNA amplification in positive samples was performed using real-time polymerase chain reaction (qPCR). Species identification of Leishmania was conducted through nested PCR, followed by sequencing. Leishmania spp. infection was detected in 2.92% (13/445) of the animals. Sequencing revealed that L. infantum infected three animals, while the species of the agent in the other animals could not be determined. The results indicate the presence of Leishmania spp. in the studied region, primarily affecting the local wildlife. These findings not only highlight the risk of transmission to domestic animals and humans in close contact with forest remnants, but also underscore the critical role of these fragments in supporting native fauna. However, it is worth noting that the continuous deforestation of these forest remnants could lead to increased contact between wildlife, domestic animals, and humans, thereby elevating the risk of transmission. Full article

Island ecology plays an important role in explaining various ecological and evolutionary processes. Small, isolated oceanic islands, exemplified by the Azores Archipelago, are especially vulnerable to adverse environmental conditions and human impact. The study aims to evaluate the impact of urbanization, especially the urban greening space, on the structure and dynamics of avian communities associated with various landforms in an urbanized landscape in one of the nine islands of the Azores Archipelago, São Miguel Island, in the northeast Atlantic Ocean. Samples were collected in the second half of April 2024. The line transect method (43 transects with a total of 37.4 km) was employed to count all bird species breeding in different landforms distinguished in the city: coastal land, urbanized land, rural land, and urban greening space. The obtained results showed that the number of breeding species was much higher in urban greening spaces (n = 20) than in the other lands (n = 10–14 species). Both cumulative dominance and dominance indices were much lower in urban greening space than in the other landforms. The Sørensen Index of Similarity between the four main land categories distinguished in the city varied between 0.62 and 0.96, being the lowest between the coastal and urban greening space, and the highest between the urbanized and rural lands. Two main feeding guilds were distinguished in the study area: granivores and insectivores. The former guild clearly dominated over the latter in all major land categories distinguished. Clearly, the proportion of granivores increased with urbanization. Also, two nesting guilds were distinguished: buildings and trees/shrubs. The former was dominant in all land categories except for the urban greening space where the tree/shrub nesting guild was more numerous than the building guild. The tree/shrub guild declined with urbanization. A general trend was recorded: the higher the level of urbanization, the lower the percentage of urban greening space, and in consequence, the lower the number of bird species and diversity indices, but the higher the cumulative dominance and dominance indices. The overall density of birds remains, however, distinctively similar. In the future, data on the population densities and dominance of particular species should be collected in urbanized landforms in other towns of the Azores Archipelago and Macaronesia at large. Full article

Paracentrotus lividus is a widely distributed species in the Mediterranean Sea and North-East Atlantic Ocean, where it plays an important ecological and commercial role. The growing demand for its delicious gonads has rapidly led to the overexploitation of the natural populations around Sardinia (western Mediterranean). The present research aimed at understanding the population genetics of the species within the area, and at gathering data on the juveniles produced in an experimental ‘conservation hatchery’ facility. A multilocus approach was used, combining mitochondrial genes (COI and Cytb) and microsatellite markers. Overall, both the microsatellites and mitochondrial results indicate that the hatchery-produced juveniles were less genetically diverse and significantly divergent from the wild populations, most likely because of a bottleneck effect due to the insufficient number of parental breeders used. As concerns the wild populations, despite the high harvesting pressure, they still have a good quantity of genetic variation. A weak overall differentiation was found, suggesting extensive gene flow among the sites. However, the differentiation in the pairwise comparisons between the wild Sardinian samples was found to be significant with regard to the mitochondrial sequences, to be further investigated with additional studies. These data provide the scientific knowledge necessary to inform future management actions and to improve future aquaculture protocols. Full article

In the North Atlantic region, the transition from the very cold Lateglacial Stadial (GS-1) to the temperate Holocene was abrupt, with a rapid increase in temperature of several degrees, after which the low-stature, cold-tolerant Stadial vegetation was replaced through the immigration and rapid succession of tall herb, heath, and shrub communities towards Betula woodland of varying density. In northeast England, pollen diagrams on a south to north transect between mid-Yorkshire and the Scottish border show that there was considerable variation in the rate at which postglacial woodland was established in the first Holocene millennium. In mid-Yorkshire’s Vale of York, the development of closed Betula woodland was swift, whereas in north Northumberland, near the Scottish border, Betula presence was low for the first several centuries of the Holocene, with open vegetation persisting and with shrub vegetation dominated mostly by Juniperus. Intermediate locations on the transect show there was a gradient in post-Stadial vegetation development in northeast England, with latitude as a major factor, as well as altitude. Transitional locations on the transect have been identified, where vegetation community change occurred. Vegetation development in the first Holocene millennium in northeast England was spatially complex and diverse, with the climatic effects of latitude the main controlling environmental variable. Full article

Climate change has a great impact on wildlife, which needs to be considered when designing conservation and management practices in habitats rich in biodiversity, such as wetlands and forests. Varied responses to climate change of species with different environmental preferences can be used to monitor different aspects of the environment. Since 2000, we have observed contrasting changes in the numbers of two related forest bird species, Goldcrest and Firecrest, monitored during autumn migration (14 August–1 November) over 1976–2024 by mist netting at 2 bird ringing stations on the Polish coast of the Baltic Sea. At both stations of the Operation Baltic project (Bukowo-Kopań and Mierzeja Wiślana), located ca 200 km apart, we observed a long-term decline in the number of Goldcrest since the 1980s but an increase in the number of Firecrest since the year 2000. These two species with ranges overlapping in Europe slightly differ in their preferences for breeding habitat and migration strategies. We found that in both species, the changes in migrating bird abundance in autumn at both stations were correlated with the Pan-European breeding population trends from the Pan-European Common Bird Monitoring Scheme (PECBMS) over 1982–2022. These correlations suggest that some Europe-wide factors underly these changes. Thus, we analyzed the effects of seven climate factors: the European Temperature Anomaly and the North Atlantic Oscillation Index in spring (March–April), summer (May–July) and autumn (October), and the Eurasian Snow Cover in October, on bird abundance indexes during breeding and autumn migration, using multiple regression models. Both species were more abundant during breeding and migration after warm springs, which conduce their early breeding and two broods per season, thus improving their breeding success. But with warm summers, Goldcrest were less abundant during breeding in Europe and on migration at Bukowo-Kopań. We attribute that pattern to Goldcrest’s tendency to overwinter in Scandinavia after warm summers. We suggest that this strategy became an ecological trap, as the climate change in Europe involves the increase of summer temperatures by 2 °C over the last 42 years but also earlier snow in October, which impedes Goldcrest’s feeding. These factors, combined with the decreasing proportion of coniferous forests in Scandinavia, which are Goldcrest’s main breeding habitat, assumably caused the species’ decline, which we expect to continue. Firecrest showed a weaker response to snow in October, but their autumn migration at both stations shifted earlier since the late 1980s, alleviating any effect of early winters. Warm spring and summers favor Firecrest abundance during breeding and migration. Firecrest also benefit from more broadleaf trees in Fennoscandia, thus we expect this species to expand its breeding range farther northeast and to continue the population increase. The change in forest management policy in Scandinavia by planting more broadleaf trees aims at increasing biodiversity and might considerably influence the forest environment. Thus, it is imperative to identify the methods suited for early detection of such changes. We showed that monitoring the numbers of migrating birds provides good indicators of the effects of short- and long-term environmental changes on bird populations. Full article

This study revisits the taxonomy of Anthocotyle merluccii, originally described from the European hake Merluccius merluccius in the northeast Atlantic, addressing discrepancies in clamp morphology across populations. The original description from Belgium noted near-equal anterior clamp sizes, contrasting with populations from Plymouth (Atlantic) and the Mediterranean, which show marked size differences, questioning their conspecificity. We describe A. radkeaminorum n. sp. from M. merluccius in the western Mediterranean (off Algeria), distinguished from A. merluccii (Belgium) by differing anterior clamp size, genital atrium spine number, and overall anterior clamp dimensions. Populations from Plymouth, previously attributed to A. merluccii, are herein assigned to A. aff. merluccii based on differences in morphometrical traits pending further investigations. Additionally, A. radkeaminorum n. sp. differs from A. americanus in body and clamp size, atrial spine count, and hosts. Based on analysis of morphological and molecular data, we refute the synonymy of A. merluccii and A. americanus, and we reinstate the latter as a valid species. The distinction between A. merluccii and A. americanus was further supported by divergence in cox1 gene sequences analyzed from GenBank (10–11%). Finally, inconsistencies in terminal lappet hook morphology are discussed, cautioning against its use in species delineation. This work highlights the need for continued research to resolve species relationships within this genus. Full article

Managing fishery resources is crucial to ensure the marine environment continues to provide diverse goods and services. To overcome difficulties of classical methods used for fish stock management, molecular tools have shown potential to address this issue assessing both targeted and non-targeted species. This study aims to evaluate the spatiotemporal diversity of fish using 12S rRNA gene eDNA metabarcoding sequencing in the Berlengas archipelago and compare two seawater eDNA sampling sources: samples collected by fishermen during their activities and those collected by our research team. The results indicated that autumn presented the highest diversity and that the area around Berlenga Island was the richest area, increasing biodiversity across the region. Fisher-collected samples were generally less diverse than those by the research team but detected species typical of deeper and open-ocean habitats, validating this sampling method. Our study also highlighted eDNA’s role in monitoring fish species by detecting unexpected species for the region, such as Atlantic salmon (Salmo salar) and Atlantic cod (Gadus morhua), while cautioning against false positives like orange clownfish (Amphiprion percula) and blue tilapia (Oreochromis aureus). Future optimisation of our eDNA sampling methodology could better refine marine ecosystem dynamics around the UNESCO Biosphere Reserve of the Berlengas Archipelago, Portugal. Full article

Climate prediction is of fundamental importance to various sectors of society and the economy, as it can predict the likelihood of droughts or excessive rainfall in vulnerable regions. Climate models are useful tools in producing reliable climate forecasts, which have become increasingly vital due to the rising impacts of climate change. As global temperatures rise, changes in precipitation patterns are expected, increasing the importance of reliable seasonal forecasts to support planning and adaptation efforts. In this study, we evaluated the performance of NOAA/GFDL models from CMIP6 simulations in representing the climate of South America under three configurations: atmosphere-only, coupled ocean-atmosphere, and Earth system. Our analysis revealed that all three configurations successfully captured key climatic features, such as the South Atlantic Convergence Zone (SACZ), the Bolivian High, and the Intertropical Convergence Zone (ITCZ). However, coupled models exhibited larger errors and lower correlation (below 0.6), particularly over the ocean and the South American Monsoon System, which indicates a poor representation of precipitation compared with atmospheric models. The coupled models also overestimated upward motion linked to the southern Hadley cell during austral summer and underestimated it during winter, whereas the atmosphere-only models more accurately simulated the Walker circulation, showing stronger vertical motion around the Amazon. In contrast, the coupled models simulated stronger upward motion over Northeast Brazil, which is inconsistent with reanalysis data. Moreover, we provided insights into how model biases may evolve under climate change scenarios. Future climate projections for the mid-century period (2030–2060) under the SSP2-4.5 and SSP5-8.5 scenarios indicate significant changes in the global energy balance, with an increase of up to 0.9 W/m². Additionally, the projections reveal significant warming and drying in most of the continent, particularly during the austral spring, accompanied by increases in sensible heat flux and decreases in latent heat flux. These findings highlight the risk of severe and prolonged droughts in some regions and intensified rainfall in others. By identifying and quantifying the biases inherent in climate models, this study provides insights to enhance seasonal forecasts in South America, ultimately supporting strategic planning, impact assessments, and adaptation strategies in vulnerable regions. Full article

Since the beginning of the satellite era, only three tropical cyclones have been recorded over the South Atlantic Ocean. To investigate the potential occurrence of such systems since the 1900s, ERA20C, a centennial reanalysis, was utilised. This study first evaluates the performance of ERA20C in reproducing the climatology of all cyclone types over the southwestern South Atlantic Ocean by comparing it with a modern reanalysis (ERA5) for the period 1979–2010. Despite its simpler construction, ERA20C is able to reproduce key climatological features, such as frequency, location, seasonality, intensity, and thermal structure of cyclones similar to ERA5. Then, the Cyclone Phase Space (CPS) methodology was applied to determine the thermal structure at each time step for every cyclone between 1900 and 2010 in ERA20C. The cyclones were then categorised into different types (extratropical, subtropical, and tropical), and systems exhibiting a warm core at their initial time step were classified as tropical cyclogenesis. Between 1900 and 2010, 96 cases of tropical cyclogenesis were identified over the South Atlantic. Additionally, throughout the lifetime of all cyclones, a total of 1838 time steps exhibited a tropical structure, indicating that cyclones can acquire a warm core at different stages of their lifecycle. The coasts of southeastern and southern sectors of northeast Brazil emerged as the most favourable for cyclones with tropical structures during their lifecycle. The findings of this study highlight the occurrence of tropical cyclones in the South Atlantic prior to the satellite era, providing a foundation for future research into the physical mechanisms that enabled these events. Full article

In the past 42 years from 1980 to 2021, 103 regional strong cooling events (RSCEs) occurred in winter in Northeast China, and the frequency has increased significantly in the past 10 years, averaging 2.45 per year. The longest (shortest) duration is 10 (2) days. The minimum temperature series in 60 events exists in 10–20 d of significant low-frequency (LF) periods. The key LF circulation systems affecting RSCEs include the Lake Balkhash–Baikal ridge, the East Asian trough (EAT), the robust Siberian high (SH) and the weaker (stronger) East Asian temperate (subtropical) jet, with the related anomaly centers moving from northwest to southeast and developing into a nearly north–south orientation. The LF wave energy of the northern branch from the Atlantic Ocean disperses to Northeast China, which excites the downstream disturbance wave train. The corresponding LF positive vorticity enhances and moves eastward, leading to the formation of deep EAT. The enhanced subsidence motion behind the EAT leads to SH strengthening. The cold advection related to the northeast cold vortex is the main thermal factor causing the local temperature to decrease. The Scandinavian Peninsula is the primary cold air source, and the Laptev Sea is the secondary one, with cold air from the former along northwest path via the West Siberian Plain and Lake Baikal, and from the latter along the northern path via the Central Siberian Plateau, both converging towards Northeast China. Full article