Earth and Environmental Sciences

Artificial light at night (ALAN) may modify visually mediated interactions in the pelagial, yet field evidence remains scarce. We tested whether moderate-intensity ALAN aggregates planktivorous fish and reshapes zooplankton vertical distributions in a eutrophic lake. During two new-moon campaigns (May and June 2017), we assessed fish aggregation using hydroacoustics and quantified zooplankton across 0-6 m by day, in natural darkness, and under high-pressure sodium illumination. Fish formed dense aggregations in the illuminated epilimnion. Depth-integrated densities showed limited and taxon-specific responses to ALAN, whereas vertical distribution shifted consistently across multiple taxa. Responses were most pronounced in Chaoborus flavicans, which shifted deeper under ALAN, followed by large cladocerans, especially Daphnia longispina, including their gravid females, which showed reduced surface-layer prevalence and deeper nocturnal distributions. Leptodora kindtii occupied intermediate depths. Under ALAN, size-dependent vertical stratification re-emerged at night, partially counteracting nocturnal homogenisation of the upper water column. Differences between campaigns were interpreted as context-dependent variation rather than seasonal effects, but ALAN altered their spatial expression by disproportionately affecting large and reproductive individuals. Together, these results show that ALAN is primarily associated with changes in vertical distribution and predator-prey overlap rather than consistently reducing total zooplankton abundance within the sampled water column.

Coral reefs are in global crisis, with larval recruitment occurring at historically low rates. Soundscapes provide important recruitment cues for reef larvae, but the effect of sound on settlement is understudied, particularly in broadcast spawning corals. We investigated effects of sound playback on settlement of the endangered reef-building coral, Diploria labyrinthiformis. In a 2023 field study, we placed D. labyrinthiformis larvae at six sites spread across two reefs on St. Croix, U.S. Virgin Islands. We exposed larvae in-situ to 72-h playbacks of recordings from acoustically active reefs. When larvae were held in static cups of filtered seawater, settlement rates were 1.79x higher at acoustically enriched sites. In comparison, larvae enclosed in flow-through mesh tents showed minimal responses to sound playback but exhibited a tenfold difference in mean settlement between the two reefs. This is the first study to our knowledge to demonstrate settlement responses to replayed sound in broadcast spawning corals. Our results suggest that archival recordings of healthy reefs can be used cross-regionally to support coral breeding efforts, while emphasizing that corals are sensitive to multiple cue types in addition to sound. The broader sensory environment must therefore be carefully considered when selecting sites for potential acoustic enrichment.

This study investigates an optimized denitrifying bacteria-based self-healing mortar incorporating nano-graphene oxide (nGO) and fly ash (FA). In this system, denitrifying bacteria induce CaCO₃ precipitation to seal cracks, nGO promotes nucleation and improves matrix densification, and FA contributes to pozzolanic reactions that refine pore structure and enhance later-age strength. Mechanical, durability, microstructural, and crack-healing properties were evaluated. The optimum combination of 10⁸ cells·mL⁻¹ bacterial concentration, 0.06 wt% nGO, and 15 wt% FA increased compressive strength by 52% at 28 days compared with the control mortar, while the combined system showed an overall improvement of 85%. With prolonged curing, the strength gain reached 120% at 180 days. Crack-healing efficiency was 100% for 0.1-0.2 mm cracks and remained ≥ 97% for cracks up to 1.0 mm after 28 days of healing. Ultrasonic pulse velocity recovery exceeded 99.5%, indicating restoration of internal continuity. Water absorption decreased from 2.95% to 0.79%, corresponding to a 73% reduction in permeability-related uptake. SEM-EDX analysis confirmed dense CaCO₃ deposition within healed cracks and the interfacial transition zone. These results demonstrate the potential of denitrification-based bio-nanomodified mortar as a durable and low-permeability construction material.

Amid the dual contexts of rapid urbanization and global warming, the Surface Urban Heat Island (SUHI) effect has been identified as a pivotal climatic issue that poses severe threats to urban sustainable development and public health. Urban Resilience (UR), in turn, has been widely recognized as a systematic and holistic pathway to mitigate the SUHI effect and optimize the urban thermal environment. Based on the three-dimensional Scale-Density-Morphology theoretical framework, this study constructed a comprehensive UR evaluation system, using 2000-2024 long-time-series remote sensing and socio-economic data, combined with XGBoost-SHAP, Double Machine Learning (DML), and Geographically and Temporally Weighted Regression (GTWR) models, to systematically analyze UR's nonlinear effects, critical thresholds, diurnal differences, and spatiotemporal differentiation on SUHI. During the study period, the SUHI in the Guanzhong Urban Agglomeration continuously intensified, increasing from 0.14 °C to 0.48 °C during the daytime and from 0.10 °C to 0.22 °C at night. Concurrently, the UR exhibited a continuous decline, dropping from 0.12 to 0.06. Urban resilience exerted a significant negative causal effect on the SUHI, demonstrating typical nonlinear and threshold characteristics. Specifically, the daytime threshold effect of UR was identified at 0.104, beyond which it began to mitigate the SUHI and gradually stabilized. The nighttime threshold was 0.018, beyond which it continuously mitigated the SUHI. Spatially, the cooling effect of UR strengthened progressively from west to east. Temporally, the mitigation threshold of UR continuously advanced from 0.108 to 0.037, accompanied by an increasing degree of mitigation. This study elucidates the complex interactive feedback mechanisms between resilience and the thermal environment in arid and semi-arid urban agglomerations. These findings provide a scientific basis for optimizing the spatial structure and enhancing climate adaptability within the Guanzhong Urban Agglomeration.

We here describe a fossil jaw fragment from the middle Eocene (Lutetian) Uzunçarşıdere Formation in Anatolia, pertaining to a pleurodontan iguanian. This region during most of the Eocene was part of an isolated insular landmass, called Balkanatolia, that is mostly known for its peculiar and diverse insular mammalian fauna. The lizard specimen represents the first evidence of Eocene reptiles from Balkanatolia, providing a first glimpse into the herpetofaunas of this, now lost, insular landmass. The fossil material is rather fragmentary, precluding a more precise identification, but its distinctive tooth morphology confirms the presence of pleurodontan iguanians in the region for the first time. The presence of a distinct mesiodistal groove along the apical crest of the central cusp in the teeth of the Anatolian pleurodontan is of particular interest, as this feature is otherwise observed only in the Eocene genera Cadurciguana from Western Europe and Parasauromalus from North America, plus the extant American lineages of Dactyloidae, Leiocephalidae, and Polychrotidae. Interestingly, this feature seems to be absent from all other pleurodontans, including the abundant Eocene corytophanid Geiseltaliellus. The new find indicates another successful overseas dispersal of pleurodontans, a group that has repeatedly colonized distant landmasses, including oceanic islands, throughout its evolutionary history. Taking into consideration the diversity and abundance of pleurodontans in the Eocene of Europe and the total absence of the group from coeval Africa and Asia, it is likely that the new Anatolian iguana arrived from the former continent sometime between the early and early middle Eocene.

Repeated mining in thick coal seams and close-distance coal seam groups induces recurrent development of overburden fractures, resulting in persistent loss of groundwater bodies. Immobilized microbial cement materials are expected to achieve the goal of "one-time grouting with repeated seepage-resisting" for managing water-conducting fractures in overburden strata. Through saturated water absorption tests, nuclear magnetic resonance (NMR) detection, uniaxial compression tests, acoustic emission (AE) monitoring, scanning electron microscopy (SEM) imaging, X-ray diffraction (XRD) analysis, and triaxial seepage experiments, this study investigated the load-bearing failure characteristics and repeated seepage-resisting performance of a certain immobilized microbial cement. Compared with ordinary cement, the calcium carbonate produced by the biochemical action of this immobilized microbial additive can densify the microstructure of the specimens and reduce their porosity; however, it may induce internal stress concentrations within the specimens. Together with its retarding effect on the hydration of cement clinker, this leads to a reduction in compressive strength and makes the tensile failure characteristics of the specimens more pronounced. Under experimental conditions simulating a formation stress of 3 MPa and a formation water pressure of 0.5 MPa, the pre-cracked specimens grouted with cement and with microbial cement completed 1 cycle and 3 cycles of repeated seepage-resisting experiments, respectively. This indicates that the biocarbonation effect and hydration-retarding effect of the immobilized microbial additive can, under laboratory conditions, prevent continuous leakage of mobile water within fractures induced by repeated mining, without the need for additional nutrient solution. The water flow rate over time during the experiments follows an exponential-type function, and through coefficient fitting with a correlation above 95%, it can be expressed as an equation closely related to the repeated seepage-resisting cycle number *n* and seepage time *t*. This study can provide a theoretical basis and experimental reference for research on strata seepage control under repeated mining conditions.

This study investigates sea level trends in the North Indian Ocean (NIO) from 2003 to 2024, quantifying the contributions of thermosteric, halosteric, and ocean mass components using satellite altimetry, observation-based gridded products, and GRACE gravimetry datasets. The NIO Sea level is rising at 4.83 ± 0.22 mm/yr, driven primarily by thermosteric sea level (2.21 ± 0.16 mm/yr) followed by ocean mass component (1.69 ± 0.09 mm/yr). Sub-basinal analysis reveals strong spatial heterogeneity, with the highest rates of sea level rise in the Western Bay of Bengal (5.19 ± 0.41 mm/yr) and the lowest in the Western Arabian Sea (4.29 ± 0.27 mm/yr). A distinct halosteric contrast exists, where freshening accelerates rise in the Bay of Bengal (up to 0.65 ± 0.08 mm/yr in the Eastern Bay), and increasing salinity suppresses it in the Arabian Sea (down to -1.12 ± 0.12 mm/yr in the western Arabian Sea). Furthermore, while western sub-basins are predominantly steric-driven, eastern sub-basins of Bay of Bengal and Equatorial Indian Ocean exhibit anomalously high GRACE-derived mass contributions (> 3 mm/yr), likely influenced by post-seismic crustal adjustments from the 2004 Sumatra-Andaman earthquake. Interannual variability closely tracks steric changes modulated by ENSO and the Indian Ocean Dipole (IOD), triggering basin-specific responses via wind anomalies and long-period waves. Further analysis of tropical SST indices reveals that the Western Tropical Indian Ocean SST index closely mirrors the spatial correlation structures of the Dipole Mode Index, and may serve as a useful indicator of regional sea level variability, particularly over the Equatorial Indian Ocean and Bay of Bengal. Ultimately, unlike the predominantly mass-driven global trends where both mass and steric contributions are of comparable magnitude, the NIO remains uniquely steric-dominated and the sea level budget leaves a residual of 0.98 mm/yr (~ 20% of the total trend), which, while comparable to uncertainties in individual components, highlights remaining challenges in fully closing the regional sea level budget.

Market vendors play a critical role in food distribution, employment creation, and the functioning of the urban economy in Uganda, yet they operate within highly flood-prone environments. Despite their socio-economic importance, there remains limited empirical understanding of the factors shaping flood impacts and the adaptive capacity of informal market vendors in such urban vulnerable contexts. This study therefore seeks to address this knowledge gap by examining the determinants of flood impacts and adaptation capacity among market vendors in Walukuba-Masese, Jinja City. A cross-sectional survey of 263 vendors was conducted using structured questionnaires. Data were analyzed using descriptive statistics, Chi-square tests, and logistic regression models. Logistic regression results showed that vendors with 5-9 years of business experience had significantly lower flood impacts (β = -1.89, p < 0.05) compared to vendors with fewer years of operation. Vendors who were not members of business associations were about 5.7 times more likely to experience flood impacts compared to those who were members. Adaptive capacity analysis revealed several significant determinants. Access to savings (β = 4.876, p < 0.001), access to credit (β = 2.616, p = 0.002), availability of storage containers (β = 2.939, p = 0.002), receipt of early warning information (β = 3.857, p < 0.001), disaster preparedness training (β = 4.097, p < 0.001), vendor association membership (β = 1.680, p = 0.002), and support from family or community during floods (β = 4.014, p < 0.001) significantly enhanced vendors' adaptive capacity. Additionally, the type of goods sold (β = 0.214, p = 0.020) and financial loss experienced during the last flood (β = 0.090, p = 0.023) were also associated with adaptive responses. The findings highlight the need for targeted interventions such as improved drainage infrastructure, expanded access to financial services, disaster preparedness training, and strengthened early warning systems to enhance the resilience of informal urban enterprises and support inclusive flood risk management in Uganda's rapidly growing secondary cities.

Groundwater depletion threatens the sustainability of rice-wheat (RW) cropping systems in north-west India. Reducing evapotranspiration (ET), particularly its non-beneficial component soil evaporation (Es), is essential to improve water productivity and limit groundwater decline. This study combines field measurements and APSIM modeling to quantify water balance components and ET partitioning in a dry-seeded RW system in Punjab, India, under conventional and zero tillage (CT, ZT), with and without rice straw mulch. Annual ET losses were high (1,000-1,400 mm), of which 400-500 mm occurred as Es, predominantly during the rice phase, which also dominated deep drainage. Zero tillage was often associated with lower ET but responses varied with crop growth and irrigation differences rather than a consistent tillage effect. Mulch consistently suppressed Es from wheat but had small and inconsistent effects on system-scale ET and transpiration (T). Water productivity with respect to ET and T was generally higher under ZT than CT, reflecting system-dependent management interactions rather than an intrinsic tillage advantage. These findings highlight substantial ET and deep drainage losses in flood-irrigated dry-seeded RW systems and identify rice-phase Es reduction as a key strategy for improving water sustainability.

Considering the significant threats posed by heavy metals (HMs) to ecosystems and public health, the aim of the current study was the synthesis and characterization of β-cyclodextrin-based adsorbents, including citric acid crosslinked βCD (CA-βCD), adipic acid crosslinked βCD (AA-βCD), and βCD-based metal-organic framework (βCD-MOF), and evaluation of their efficacy in the removal of Pb 2+ , Cd 2+ , and Cu 2+ ions. The synthesized polymers were analyzed by FTIR, XRD, SEM, BET, and zeta potential methods to assess their structural, morphological, and surface characteristics. In the multicomponent system (adsorbent dosage 1 g/L, initial metal concentration 100 mg/L, pH 6.0 at 25℃), βCD-MOF exhibited the highest removal efficiency, particularly for Cu 2+ (~ 80%), followed by Pb 2+ (~ 40%) and Cd 2+ (~ 20%), outperforming AA-βCD and CA-βCD. The preferential adsorption of copper is attributed to its smaller ionic radius and higher charge density, which enhance electrostatic interactions with polymer ligands. Single-component experiments using βCD-MOF (as optimal adsorbent, 3 g/L) revealed excellent removal efficiencies, Cd 2+ : 99.93%, Pb 2+ : 97.02%, Cu 2+ : 96.30%. Interestingly, while Cd 2+ was most efficiently removed alone, despite its larger hydrated radius and higher pKa 1 , competitive adsorption favored Cu 2+ , indicating ligand selectivity shifts under mixed conditions. Equilibrium data were best fitted by the Langmuir model, with maximum single-state adsorption capacities of 142.85, 136.99, and 120.48 mg/g for Cd 2+ , Pb 2+ , and Cu 2+ , respectively. The results of real water treatments demonstrated positive relationship between water hardness and Cd 2+ removal efficiency using βCD-MOF adsorbents. These findings highlighted the role of βCD-MOF as a promising candidate for scalable water purification technologies.