Groundwater, the largest readily accessible freshwater resource on Earth, supplies drinking water for billions and underpins over 40% of global agriculture production. Despite the rising scientific focus on climate-driven pressures, region-specific bibliometric assessments remain limited across disciplines. Increasing groundwater demand and excessive extraction are stressing this vital resource, causing declines in availability and quality, along with potential degradation and recharge uncertainty. This bibliometric analysis integrates Indian case studies with a global perspective using Web of Science and Scopus Core Collection data (726 publications since 2000, systematically reviewed via PRISMA from 140 peer-reviewed studies) to evaluate groundwater response through direct and indirect casual factors. Results underscore the need for a multi-dimensional framework addressing challenges at regional and global scales. ‘Climate change’ dominates discussions on altered precipitation, glacial retreat, recharge, subsurface flows and sea level rise impacts emerging hotspots shaping future research. Seasonal aquifers show monsoonal variability: intense rainfall events often boost runoff over recharge, leaving systems stressed post-rainfall. Indirect drivers (industrial/agricultural pollution, Landuse change, unsustainable extraction, and irrigation) amplify these dynamics, compounded by data scarcity, spatial heterogeneity, and poor representation in climate models. This synthesis links groundwater-climate interactions across scales, and advances adaptive management and resilience strategies.

Though formulated from the margins as its author is tauiwi (a foreigner) in Aotearoa New Zealand, this article examines how Indigenous epistemologies based on the concept of reciprocity, such as the vā (the space between), talanoa (conversation), and aroha (kindness, empathy, love), challenge unequal human/non-human relationships set up by settlers in Oceania. It especially focuses on two poems from Aotearoa New Zealand which evaluate the colonial legacy on Indigenous cultures and endemic ecosystems in the Pacific: “Unity” by Selina Tusitala Marsh (Sāmoan, Tuvaluan, English, Scottish, and French New Zealander) and “Poem for the Commonwealth, 2018” by Karlo Mila (Tongan, Palagi, and Samoan New Zealander). These poems give shape to a spacetime which is respectful of Pacific epistemologies enabling poets to testify to alarming human/colonial-made environmental issues, such as sea level rise, marine pollution, and the extinction of endangered species. Positioning themselves as witnesses, actors, and guardians of stories, the poets of the corpus participate in the decolonization of the land, the English language, and Pacific literatures.

This paper delves into the escalating risks faced by urban coastal communities due to tidal and storm flooding, exacerbated by climate change-induced Sea Level Rise (SLR). Projections indicate a potential increase in sea levels by at least 3 feet by 2100, with historical data revealing an average annual rise of 1.2–1.7 mm since the 1900s. With over 300 million individuals inhabiting coastal areas, low-lying regions emerge as particularly vulnerable to the impacts of SLR. This accelerated rise amplifies the significant challenge of nuisance flooding, a local-scale issue aggravated by high tide and winds, leading to inundation, road closures, infrastructure deterioration, the jeopardizing of essential systems such as sewage networks, and much more. Adopting a multidisciplinary approach, this paper aims to explore innovative resilience solutions within coastal urban communities, acknowledging the complex interplay among environmental, social, and economic factors. Through a comprehensive literature review, it examines various topics including SLR, adaptation strategies, retreat options, storm surge flooding, and rainfall-induced inundation. These topics are analyzed across different scales of intervention, encompassing planning, city, and architectural design, to identify optimal pathways for adapting to rising seas and ensuring a sustainable future. Serving as a framework for architects, urban designers, planners, and policymakers, this paper provides insights into the sustainable development of coastal urban communities by promoting adaptive and forward-thinking design approaches. By aligning with the UN Sustainable Development Goals 11 and 13, this paper ultimately contributes to the advancement of more resilient urban development in response to the challenges posed by climate change, thereby striving toward a sustainable future.

In this paper, we explore how coastal communities, often portrayed through narratives of risk, socioeconomic decline and displacement, might instead be represented in ways that foreground local identity, resilience and everyday lived experience. Drawing on a community-focused exhibition held in the village of Borth, West Wales, we examine how residents experience, remember and adapt to life on the shifting shoreline. Situated at the frontline of climate change and sea level rise, Borth has frequently been framed by the media and policymakers as a place of vulnerability. Yet interviews and community contributions to the exhibition revealed more complex local perspectives, shaped by a strong sense of identity rooted in Borth’s maritime past, personal connections to the power of the sea, and creative expression at the shoreline. The collaboratively developed exhibition – featuring photographs, objects and local stories – served both as a record of coastal life and as a space for discussion and reflection. By highlighting their long-standing relationships with the sea, residents sought to challenge a sole focus on problem-related narratives, instead emphasising the diversity, complexity and richness of coastal experience. We argue for the value of community-centred, arts-informed approaches in coastal research and adaptation planning, showing how they can promote dialogue, affirm local knowledge, and better support communities navigating environmental change.

Abstract Deciphering records of deep-time sea level, climate, and oceanographic variation from drowned carbonate platforms is useful, including perhaps to help predict risk of drowning on modern platforms experiencing anthropogenic sea-level rise. However, prediction is complicated by incomplete understanding of how observed platform geometries record different drowning processes. Here we analyze seismic-scale numerical stratigraphic forward model results that suggest backstepping drowning geometries occur when platform-top sediment transport redistributes sediment and drives complex autogenic production-transport feedbacks that help maintain a broad shallow-water platform-top area. In contrast, without sufficient sediment transport on platforms dominated by in-situ production, pinnacle drowning geometries tend to be produced. These results suggest platform drowning geometries represent a complex mix of controlling processes that, with careful interpretation, could provide robust information about deep-time climate and sea-level change, and may also help predict evolution of modern platforms responding to rising global sea level.

Camellia mairei var. lapidea belongs to Theaceae family, which has beautiful red flowers used as ornamental plant and seed oil is edible. In this study, C. mairei var. lapidea was first found to have natural distribution in Northwest Vietnam. It grows naturally in an evergreen broadleaved forest on the elevation of 2,100 m above sea level. There were only two adult individuals found, which bloomed and fruited numerously. Ripen fruits were much available on the forest floor, however seedlings or saplings were not available. C. mairei var. lapidea grows on Ferralsols soil with a soil depth of > 1.2 m, low rock content, low soil moisture, and well-drained soil. The maturity individuals may reach to 12 m tall and 18 cm in diameter at breast height. C. mairei var. lapidea flowers during December-February and ripen fruits appear during May-July. After ripening, whole fruits fall with fruit cover and seeds inside. C. mairei var. lapidea exhibits significant potential for vegetative propagation through cuttings, with IBA at 0.5% (w/w) in powder form being the most effective treatment. Even cuttings taken from the natural forest can achieve a rooting ratio of 40% with IBA 0.5%, higher than control of 33.3% at 4 months of growth. With the treatment of IBA 0.5%, cuttings also have the highest shoot number (1.8 shoots), highest root number (6.7 roots), and longest root length (2 cm). It is recommended that further studies should be conducted for C. mairei var. lapidea to meet its potential for ornamental use and oil production.

Abstract. Permafrost degradation significantly affects the stability of rockwalls in high altitude regions. Monitoring rockwall permafrost is essential for assessing potential geohazards. While borehole temperature measurements are the most direct permafrost monitoring approach, they lack sufficient spatial representation in such highly heterogeneous ground conditions. Conversely, geoelectrical measurements can provide more comprehensive insights into these complex patterns and dynamics. This study investigates the permafrost dynamics and intends to detect potential hydrogeological processes at the Aiguille du Midi (3842 m a.s.l. (meter above sea level), French Alps) using repeated and Automated-Electrical Resistivity Tomography (A-ERT) approaches, covering a period of 3.5 years (June 2020–December 2023). A total of three geoelectrical profiles have been installed on three faces of the Aiguille du Midi (N–W, S and E). An automated acquisition system for permanent resistivity monitoring and remote data acquisition is implemented. A time-lapse inversion technique is employed to get the temporal and spatial variations of electrical resistivity at seasonal and interannual time scales. The data revealed significant variations in active layer thickness across rock faces, along with a slight decrease in electrical resistivity at depth, indicating permafrost warming over time. However, they did not provide clear evidence of water pressurization in rock fractures. Using a petrophysical model, calibrated with laboratory measurements of the temperature dependence of electrical resistivity of granite sample, we estimated the temperature within the frozen zone from the resistivity measurements, under favorable conditions at surface in summer and autumn. Validation against direct temperature measurements in a 10 m depth borehole along the NW profile indicates a mean absolute error less than 1 °C within the frozen zone. This research underscores the efficacy of ERT as a promising, non-invasive tool for quantitative monitoring of permafrost dynamics in Alpine environments. It also reveals challenges associated with conducting A-ERT in high mountain rockwalls where the contact resistance is very high (∼500 kΩ) and sometimes intermittent due to factors such as thunder strikes and rockfalls.

Oceanfront relief varies along coastlines and serves as the first barrier to wave and surge damage. However, forecasted increases in storm frequency and sea levels are anticipated to enhance coastal erosion, potentially weakening this protection. The land–sea transition is variable along the New England coast, USA, and this variability has produced a range of coastal morphologies that can vary over short distances. It is important to track the beach transition zone to better understand transformations of the system and related hazard risks. A combination of field and computer-based methods was used to evaluate the beach transition zone of southwestern Rhode Island to determine alongshore variability and dynamics. More specifically, a decadal-scale study was conducted to examine changes in morphology from 2011 to 2022, and a short-term study at South Kingstown Town Beach examined changes from November 2023 to January 2024 using time-series drone-derived elevations. Classification of over 500 cross-shore transects illustrated the dominance of sedimentary shorelines, with smaller areas of rocky outcrops and hardening. Analysis of four different years (2011, 2014, 2018, and 2022) determined that beaches with dune morphology were the most common type of transition zone (41–47% of the transects) and transects with a high bank upland were the next most frequent class (34–41%). Following Hurricane Sandy in 2012, a 6% decrease in the number of dune-classified transects was measured; however, one-third of those recovered dune morphology by 2022. The greatest beach transformations over the short-term study occurred in response to strong storms in the 2023–2024 winter season, during which lateral beach movement (erosion) exceeded 15 m in portions of South Kingstown Town Beach. Dune erosion was accompanied by overwash flooding and deposition, and the area remained low-lying and thus vulnerable to future impacts. The beach transition zone classification and insights from this research will be informative for future planning by coastal communities by determining at-risk shorelines based on underlying geology and the stability of morphological features.

Freshwater wetlands are among the most threatened ecosystems in the world, with more than 60 % loss in Mexico. Annona glabra L. dominates many neotropical freshwater swamps but remains poorly studied despite its ecological importance. The aim of this work was to conduct a comprehensive review of the biological, ecological, and ethnobotanical aspects of A. glabra and to assess its role as a key wetland species and its potential for medicinal applications, ecological restoration, and climate change adaptation. The research was carried out in La Mancha-Diada and El Salado, Veracruz, Mexico, with comparative data from La Mancha-CICOLMA. We combined a bibliographic review with field measurements (2018-2019) of tree density, diameter at breast height, height, and monthly litter collection. In addition to environmental parameters: hydrology and salinity. The results demonstrated that A. glabra exhibits flood tolerance and moderate salinity resistance through morphological adaptations (aerenchyma, adventitious roots, hypertrophied lenticels), maintaining photosynthesis during flooding. Tree density reached 833 individuals/ha, with a basal area of 188.94 m²/ha. Annual litterfall averaged 12.4 t/ha, and seed production reached 3.7 million seeds/ha/year. Ethnopharmacological analyses revealed antimicrobial, anti-inflammatory, anticancer, and larvicidal properties. Functioning as a “freshwater mangrove,” A. glabra is crucial for ecosystem services. It shows high potential for ecological restoration but requires management due to its invasive capacity. Sea level rise and salinization represent a significant threat, underscoring the need for urgent conservation strategies.

Blue spaces are recognised as vital public resources that support human health and wellbeing through pathways such as physical activity, psychological restoration and social connection. Coastal environments are especially distinctive for their multisensory stimuli, expansive vistas and cultural significance, with benefits shaped by environmental quality, accessibility and usability. Climate change threatens these benefits via extreme events, such as storm surges and flooding, and gradual processes, including rising sea levels, erosion and warming temperatures, which can also alter people's perceptions, engagement patterns and cultural connections. A conceptual framework is proposed to explore the mechanisms through which climate change affects coastal amenities. This framework offers a structured approach to understanding how environmental processes, interventions and social factors interact to shape health and wellbeing outcomes, and identifies where, why and at what scales adaptation interventions can be most effectively applied. Adaptation measures can help sustain wellbeing benefits under climate hazards by reinforcing positive feedbacks, such as stewardship and investment in amenities, while mitigating negative feedbacks from environmental degradation or overuse. Climate-informed adaptation of coastal amenities, integrating ecological, social and governance considerations, is essential to preserve quality, access, usability and the equitable delivery of health benefits. The framework therefore offers both a theoretical basis for understanding climate-wellbeing interactions and a practical tool to support internationally relevant interventions, policy development and co-designed justice-sensitive adaptation strategies that sustain the health, cultural and social value of blue spaces under climate change.

ABSTRACT Coastal dune systems are dynamic environments that provide vital natural protection against storm surges and sea level rise, yet many are experiencing accelerated erosion under growing climatic and anthropogenic pressures. This study assesses recent morphological changes in a small coastal dune system at Lundin Links, Scotland, using high-resolution UAV LiDAR and UAV SfM photogrammetry datasets. The survey employed RTK-enabled drone platforms and generated precise terrain models supported by ground control points. A comparative analysis of datasets reveals strong geometric consistency between two datasets. Given its lower cost and simplicity, photogrammetry proves sufficient for capturing small-scale dune dynamics in open coastal environments. Multitemporal digital elevation models derived from UAV and historical LiDAR data, volumetric and spatial analyses show a shift from initial localized accretion to widespread erosion, with an acceleration in sediment loss after 2020. Change detection highlights crest lowering and landward retreat, raising concerns about future exposure in areas adjacent to golf course fairways. These changes align with national coastal change trends and is likely exacerbated by recent extreme weather events. This research demonstrates the effectiveness of UAV SfM and support more frequent, accessible monitoring approaches to inform adaptive management under increasing climatic risk.

Abstract. Constraining the dynamic evolution of past ice sheets is critical for unravelling their responses to external forcing and feedbacks over long timescales. This is particularly true in the context of marine ice sheet collapse, as this is one of the largest sources of uncertainty for future sea-level rise projections. The Iceland Ice Sheet (IIS) provides an empirically constrained case study for investigating such an instability, having retreated from a predominantly marine-based ice sheet to isolated mountain ice caps during the last deglaciation. However, previous reconstructions of the IIS have been limited by either sparse data or a restricted exploration of model parameter space, lacking a robust quantification of uncertainties. Here, we address this gap by performing a truncated history matching of the last glacial cycle of the IIS. We use the Glacial Systems Model (GSM) constrained by a curated set of geochronological data to generate an envelope of not-ruled-out-yet(NROY) ice sheet histories. Our results indicate that numerous asynchronous ice streams effectively drain ice from the interior to the margins, resulting in an extensive yet relatively thin ice sheet. During its local Last Glacial Maximum (23.6–20.9 ka), the IIS reaches the continental shelf edge in most sectors with a total volume of 0.41 to 0.76 metres equivalent sea level (m e.s.l.). In the most extreme NROY glaciation scenarios, our model reveals an ice bridge connecting the Iceland and Greenland ice over Denmark Strait. We find that accelerated ice discharge (at the grounding line) dominates mass loss during deglaciation. This acceleration is primarily driven by atmospheric warming through a cascade of mechanisms: surface meltwater induces hydrofracturing, leading to both ice shelf disintegration and tidewater calving, which in turn reduces buttressing and triggers rapid ice stream acceleration. The critical role of hydrofracturing in enabling model capture of deglacial data constraints is shown by explicit sensitivity experiments. This thereby supports inclusion of hydrofracturing for modelling of ongoing ice sheet response to climate change.

Abstract The past few decades of work on stratosphere-troposphere teleconnections have unearthed a variety of different time scales of both upward and downward propagation and their connection to weather at the surface. In an attempt to identify significant patterns of covariance between the surface and stratosphere without imposing an expected pattern or timescale, we apply Maximum Covariance Analysis (MCA) with a variable time lag between pairs of tropospheric and stratospheric fields. Using over 60 years of ERA5 reanalysis for Northern Hemisphere winters, we use MCA to pick out the time lags and patterns corresponding to the largest covariance between the surface and the stratosphere. By applying new methods to an existing problem, we both verify certain results from previous literature and unearth new insights into the nature of stratosphere-troposphere teleconnections. We find that the greatest covariance occurs when the surface precedes the stratosphere by up to 9 days, corresponding to a sea level pressure anomaly with one pole over the Gulf of Alaska and another over the Ural blocking high that is followed by changes in stratospheric potential vorticity, zonal wind, and EP flux. We find evidence for a downward influence of stratospheric potential vorticity and zonal wind on sea level pressure at a time scale of 3–4 days, with a secondary influence from zonal wind alone at 2–3 weeks. The downward influence is characterized by a weaker (stronger) polar vortex followed by anomalously high (low) sea level pressures over the Arctic Ocean, but it does not produce an appreciable anomaly in minimum surface temperatures.

Ferrarini, Giovanni, Mattia Canevari, Valeria Azzini, Piergiuseppe Agostoni, Beatrice Pezzuto, and Carlo Vignati. Physiological responses to acute hypobaric and normobaric hypoxia: Differences in maximal exercise and clinical impact. High Alt Med Biol. 00:00-00, 2026.-Hypoxia, defined by inspired partial pressure of oxygen (PiO2) <150 mmHg, has been extensively studied in conditions of both reduced barometric pressure (hypobaric hypoxia, HH) and reduced inspired fraction of oxygen (FiO2) at sea level (normobaric hypoxia, NH). Traditionally considered interchangeable, mounting evidence indicates that HH and NH elicit distinct cardiovascular, ventilatory, and gas-exchange responses during physical effort, likely due to factors beyond PiO2, including air density, alveolar gas composition, exercise modality, and the age and sex of the individual performing the effort. A thorough understanding of how different hypoxic modalities affect exercise responses provides fundamental insights into human physiology and pathophysiology under extreme conditions, with practical implications for sports medicine and athletic training, as well as for patients with pathologies potentially influenced by hypoxia dealing with high altitude. This narrative review synthesizes current evidence on the differential effects of HH and NH on exercise responses, with an emphasis on maximal exercise capacity and underlying the physiological mechanisms regarding cardiovascular function, ventilatory adaptation, and gas-exchange responses, also outlining the implications for athletes, clinical populations (heart failure, chronic obstructive pulmonary disease, pulmonary hypertension), and altitude medicine.

Purpose This paper aims to explore the various collective mitigation strategies used by coastal communities affected by disasters related to sea level rise (SLR). Climate change has increased SLR each year, resulting in disasters associated with SLR in several coastal areas. By exploring ways of managing space as a form of collective adaptation, it may be possible to identify strategies for disaster mitigation in coastal areas. Design/methodology/approach In this study, a qualitative method was used to conduct the research in Tambaklorok, Semarang and Morosari, Demak. The case study was chosen because of the unique way in which this community adapts to the disaster of SLR, as well as how this community negotiates with water daily. Direct observation, interviews regarding local practices and recording of location conditions were used to collect data. Data analysis is conducted through the use of diagrams to interpret spatiality strategies. Findings This study concluded that there is a collective community strategy in coastal areas, consisting of three components: (1) regulating affordability, (2) occupying in-between spaces and (3) repurposing submerged land. This paper shows that local context-based disaster mitigation strategies enable the emergence of regional spatial forms with specific characteristics. Originality/value The findings of this study provide the basis for the creation of a disaster mitigation model based on SLR that takes into account local conditions and practices as opposed to generalizing them across different regions.

This paper provides a lithostratigraphic correlation of the Middle Eocene to Upper Miocene rock units of the Al Watiyate region of Al Jabal Al Akhdar, Cyrenaica, NE Libya. Data from this study were derived from measured vertical stratigraphic logs in six main studied areas: Daryanah-Al Abyar road cut, Wadi Al Kuf, Wadi Sidi Yossef, Wadi Al Juibiyah, Wadi Al Sukinyah, and Wadi Sidi Mohamed. This study needed to concentrate on the intricate details of the Tertiary carbonate rocks and how local structural or strato-structural disturbances may have shaped their spatial variations. In this regard, the main aim of this work is to establish a local lithostratigraphic correlation among the investigated stratigraphic sections and to offer some insight into the complexity of the Middle Eocene–Upper Miocene sequence concerning the stratigraphic framework. A method used for distinguishing rock units according to lithological characteristics is known as lithostratigraphic correlation. Based on the lithostratigraphic correlation, the Middle Eocene carbonate rock unit (Darnah Formation) is changed to Oligocene rock units (Al Bayda Formation) laterally in a SW to NE direction in the study region. In the southwest, the Darnah and Al Bayda formations disappear while the thickness of the Al Abraq Formation decreases. Furthermore the Al Faidiyah, Benghazi, and Wadi Al Qattarah formations, which are representative of the Miocene rock units, thickened more southwestward. The thickness variations are most likely related to paleotopography, where the rate of deposition differs from NE (high relief area) to SW (low relief area). The outcome of the northeastern uplift is due to tectonic movements. Regressive sequences characterize the Middle Eocene to Upper Miocene, indicating a periodic fall in sea level across geological time. The absence of Oligocene rock units in the Wadi Zazah and Wadi Belgares areas suggests tectonic uplift during the Early Eocene to Middle Miocene time. However, in Wadi Al Kuf, Wadi Azzad, and Wadi Al Backour, the terrain is gradually subsiding, and it appears that the sea was transgressed to continue the accumulation of Oligocene-Miocene sediments on top of the Eocene Formation. Lithostratigraphic correlation, Middle Eocene-Upper Miocene, paleotopography, Uplift, Al Watiyate region, Al Jabal Al Akhdar, NE Libya.

Abstract Rising sea levels pose a major threat to West Africa's densely populated and economically important coastal regions, which extend from Mauritania to Cameroon. Here, we explore the dynamics of Extreme Coastal Water Levels (ECWLs) from 1994 to 2015, with the aim of enhancing disaster management and prediction strategies. We found that regional differences in ECWL are primarily driven by tidal forces and wave runup, which have a direct impact on coastal erosion and floods, particularly in areas like Guinea-Bissau. This area is highly susceptible due to its wide low-lying coastal plains, which exacerbate the effects. Sea Level Anomalies (SLA) also play a critical role, as they reflect the cumulative effect of oceanographic and climatic conditions, exacerbating the impacts of tidal and wave dynamics. Although less significant, atmospheric contributions influence ECWL through storm surge and wind pattern variations. Regional climatic phenomena, particularly the Atlantic Niño, significantly influence the West African Monsoon, altering rainfall patterns and ECWL. In contrast, global climatic drivers such as the El Niño Southern Oscillation (ENSO) and the North Atlantic Oscillation (NAO) have a more subdued influence due to their less direct impact on local atmospheric conditions. Using a strategic cluster study based on annual tide and wave data, we categorise West African countries into distinct groups, enabling tailored and effective flood mitigation strategies that are aligned with their specific hydrodynamic and climatic characteristics. The study highlights the importance of tailored climate models and monitoring systems that focus on regional climate indicators such as the Atlantic Niño, which are essential for accurately predicting and managing the effects of climate changes on coastal areas in less developed countries.

Hadal subseafloor sediments host abundant and active microbial biosphere with considerable heterotrophic activity. However, carbon and nutrient cycling processes and mechanisms driven by hadal subsurface microorganisms remain poorly understood. Using culture-dependent and culture-independent methods, we characterized the diversity, metabolism, and vertical dynamics of hydrocarbon-degrading (HYD) bacteria in a subsurface sediment core (MT20-750, ~750 cm below seafloor [cmbsf]) collected from the Challenger Deep (10,816 m below sea level) in the Mariana Trench. The sediment core contained high concentrations of mid- and long-chain n-alkanes (310-8,724 ng/g), although no <C18 n-alkanes at detectable levels were present, in contrast to proximal hadal seawater samples where these compounds were highly abundant. Metagenomic analysis identified diverse genes for aerobic and anaerobic degradation of n-alkanes and aromatic compounds, distributed across a wide range of taxa, dominated by Chloroflexota, Planctomycetes, Proteobacteria, and Actinobacteria, alongside six novel HYD phyla. Metabolic reconstruction of 120 HYD metagenome-assembled genomes (MAGs) suggests distinct hydrocarbon degradation preferences and metabolic strategies among different bacterial groups. Additionally, hadal bacterial isolates from Proteobacteria, Actinobacteria, and Firmicutes were able to degrade n-alkanes (C18-36), with Dietzia maris HXX048 removing ~50% of n-eicosane within 45 days under 5°C and 50 MPa. Predicted substrate binding of C10 and C20 with AhyA and heterologous expression of almA in Chloroflexota genomes supported their degradative capacity under anaerobic and aerobic conditions. The detection of putative hydrocarbon synthesis genes, specifically oleBC and oleC, suggests that hadal heterotrophic microorganisms may synthesize hydrocarbons. These findings provide evidence for microbial hydrocarbon production and thereby support a previously unrecognized sedimentary hydrocarbon cycle.IMPORTANCEOur findings suggest that hydrocarbon degradation may play an important role in organic matter decomposition and carbon cycling in the hadal subseafloor. This degradation capacity is likely distributed through diverse metabolic pathways across a wide range of phylogenetic taxa. The detection of genes likely encoding enzymes involved in aerobic and anaerobic hydrocarbon degradation, as well as the identification of novel hydrocarbon-degrading (HYD) phyla, highlights the complexity and significance of microbial processes in hadal subsurface sediment. The widespread distribution of hydrocarbon degradation capacity in different hadal sediments suggests hydrocarbons as a potential carbon source sustaining microbial life in this extreme environment. Moreover, the presence of genes associated with hydrocarbon synthesis suggests that hadal sediment microbes possess the genetic potential for both degrading and producing hydrocarbons, pointing to a dynamic and multifaceted hydrocarbon cycle within hadal subsurface sediment.

The study aims to develop a methodology for identifying and correcting drift in the quality of orbital data to improve the accuracy of long-term trend estimates and enhance the representativeness of orbital monitoring. We establish the presence of unidirectional, statistically significant drift in the difference between satellite instrument readings and ground-based observations. We compare the last two versions of methane (CH4) measurements from the Atmospheric InfraRed Sounder (AIRS)—specifically, Level 3 versions 6 and 7 (“IR-AIRS Only”)—with data from 18 ground-based stations of the Network for the Detection of Atmospheric Composition Change (NDACC) and 11 stations of the Total Carbon Column Observing Network (TCCON) for the 2003–2022 period. We determine that adjusting ground-based measurement data to sea level using the barometric formula, which is a necessary step for proper validation, results in significant errors, especially at high altitudes. It is proposed that such an adjustment should be based on pressure measured directly at a station. Implementing this over the examined period, we determine that the residual drift of the satellite spectrometer (Satellite Spectrometer Drift or SSD) is negative and equal to 1.64 × 1014 molecules/cm2 per day or 7.62 × 10−6 ppm per day for AIRS v6 and 7.20 × 10−6 ppm per day for AIRS v7. The correction implementation significantly improves the correspondence between AIRS v6 and v7 methane data and NDACC data, resulting in close estimates of methane trends from satellite and ground-based measurements. The robustness of the proposed correction has been demonstrated by the improvement in the consistency of station-by-station trend estimates obtained for corrected AIRS data and independent TCCON ground-based observations.

Abstract This study investigates the potential impacts of frequent global coverage of satellite microwave radiances using a global atmospheric data assimilation (DA) system. Observing Systems Simulation Experiments (OSSEs) were performed using the Local Ensemble Transform Kalman Filter with the Nonhydrostatic Icosahedral Atmospheric Model (NICAM). Three different observation time intervals are examined: hourly (1H), bi‐hourly (2H), and six‐hourly (6H). 6H mimics the current coverage of Advanced Microwave Sounding Unit‐A in orbits. 1 and 2H show higher Root Mean Square Errors (RMSEs) for temperature compared to 6H due to dynamical imbalances indicated by the second time derivatives of sea level pressure. To mitigate the imbalances in 1H, we first inflate the observation error standard deviation in DA by 60% (1H‐Rinfl) and successfully reduce imbalances by 5%–10% with the temperature RMSE decreased by 10%–15%. Next, we apply the Adaptive Observation Error Inflation (AOEI) method, which adjusts the observation error standard deviations online based on the innovation statistics. 1H with AOEI (1H‐AOEI) reduces the dynamical imbalance and shows lower RMSE than that of 6H. 1H‐AOEI also shows more skill in forecasting precipitation events with intensity &gt;2 mm/hr on small scales than 6H.