Earth and Environmental Sciences

In Nigeria, extreme climate conditions, such as droughts and erratic rainfall, increasingly threaten maize production, a crucial crop that is fundamental to food security and rural livelihoods. This study investigates the marginal returns of regenerative agriculture (RA), a collection of practices aimed at restoring soil and enhancing resilience, on maize performance under these conditions, exploring its potential as a sustainable production paradigm. Using a multistage sampling approach, data were collected from smallholder maize farmers in Southwest Nigeria via structured questionnaires, capturing socioeconomic characteristics, RA practices, and maize yield outcomes. The analysis employed a Marginal Treatment Effect (MTE) framework to assess heterogeneity in RA's impacts, complemented by Seemingly Unrelated Regression (SUR) and robustness checks to estimate effects on yield, yield variability, and skewness. Results reveal that RA adoption boosts maize yield and reduces variability for adopters, with potential benefits for non-adopters, though average effects (ATE) are modest. Yield skewness increases for adopters, suggesting higher chances of greater yields. The MTE analysis highlights that benefits concentrate among farmers with low unobserved resistance (adaptability), while high-resistance farmers face reduced returns. Key adoption drivers include land ownership, credit access, and climate change perception, yet barriers like labor intensity and awareness gaps slow diffusion. These findings imply RA can enhance resilience and productivity in Nigeria's climate-stressed maize sector, but its success is context-specific, requiring targeted policies such as improved credit access, extension services, and tenure security to overcome adoption hurdles and ensure equitable, scalable impacts.

The Filter Inlet for Gases and AEROsols coupled to a Chemical Ionization Mass Spectrometer (FIGAERO–CIMS) can be used to derive volatility of atmospheric aerosol by using the temperature at thermogram maximum signal (Tmax). For complex ambient particle matrices, Tmax of an individual compound often varies, for reasons not fully elucidated. Here, we apply machine learning to study the relation between Tmax of levoglucosan (C6H10O5), a common tracer to identify the influence of biomass burning (BB) in ambient air, and a set of atmospheric and instrumental parameters for an ambient year-long FIGAERO–CIMS data set measured in the Arctic. Using three different modeling approaches, namely, multiple linear regression (MLR), random forest (RF) regressor, and XGBoost regressor, we find that the mass loading on the FIGAERO filter has the highest relevance for variation in Tmax of levoglucosan. On the basis of these results, we suggest controlling the mass collected on the filter for continuous online measurement with the FIGAERO–CIMS if quantitative volatility information is to be gained. More generally, we demonstrate the usefulness of machine learning approaches for characterization of instrumental backgrounds in complex ambient or laboratory data.

ABSTRACT The Indus Basin is a critical water resource for Pakistan, providing irrigation, drinking water and hydropower for millions. However, it is highly vulnerable to severe flooding, which is projected to worsen under climate change. This article critically reviews Pakistan's first National Adaptation Plan (NAP) and draws lessons from past major flood events, including the 2010 and 2022 floods, to assess the effectiveness of current flood risk management strategies. A systematic literature review was conducted to identify key lessons on infrastructure limitations, early warning systems (EWS), community participation, maladaptation risks and the integration of these lessons into national policies. Findings indicate that although the NAP makes significant strides in climate adaptation planning, it remains infrastructure‐focused, with limited emphasis on nature‐based solutions and rural resilience. The article concludes with recommendations to strengthen the NAP through improved stakeholder engagement, better integration of local knowledge and a balanced approach to structural and non‐structural interventions.

/g for ozone and UV aging. Isotherm experiments with phenanthrene showed a decrease in adsorption with surface oxidation, while, for 9-phenanthrol, adsorption was higher for UV- and ozone-aged MPs than pristine MPs and declined for the highly oxidized persulfate-aged MPs. These results demonstrate that different oxidation strategies produce structurally and functionally distinct MPs, highlighting the importance of the aging protocol in laboratory studies.

In East and Southern African cities, pit latrines are the most common household sanitation system and often require manual emptying. City authorities in the region have begun to formalize service providers, and, along with service providers, require cost data and analysis to optimize service delivery and reduce costs to minimize public funding contributions toward a large funding gap. We analyzed financial and operational data from 23 formal service providers and 260 households in Malawi and Uganda. Total Annualized Cost per Household (TACH) was calculated to understand unit costs and cost structures, and scenario modeling was used to analyze cost drivers. Manual emptying is higher TACH than mechanical emptying at full capacity utilization because of higher labor costs. TACH varies between households due to different annualized sludge emptying rates. Service providers report operating below full capacity, increasing TACH and not justifying vehicle ownership over rental. Households prefer low-volume and low-price emptying to manage budgets, but this increases TACH unless service providers coordinate to maximize capacity. Options are discussed for city authorities and service providers to minimize TACH and improve vertical equity between emptying methods and horizontal equity between households, including replacing direct user-payments with frequently collected citywide payments and managed emptying services.

Water availability in the lithosphere has been crucial to the geological evolution of Earth as well as the emergence and persistence of life. The global geological water cycle associated with plate tectonics has been understood as a system controlled by the presence of oxygen and hydrogen, either in fluids and melts or bound within mineral structures. However, recent work on H 2 production in the lithosphere indicates that a water mass equivalent to about 25 to 50% of global annual water inputs into subduction is converted to H 2 every year. This H 2 can be decoupled from the water cycle and potentially lost to space over geological timescales. Here, we show that the interaction of H 2 -rich fluids with oxygen-bearing minerals results in the formation of unconventional redox water. This influences the residence time of hydrogen in Earth’s interior and offers previously unidentified perspectives on how hydrous fluids, minerals, and melts may form in initially dry geological reservoirs.

The dawn of animal life is preserved by fossils of the Ediacara Biota, which have been separated into three biotic assemblages: the Avalon, White Sea, and Nama. Geographic and temporal isolation of these faunas leads to uncertainties regarding patterns of change. We report the discovery of unambiguous fossil communities belonging to the White Sea assemblage from the paleocontinent of Laurentia in the Blueflower Formation, Mackenzie Mountains, Canada. Unlike previous localities, sedimentological and geochronological evidence supports an older origin and deeper-water setting for this assemblage, including the oldest motile bilaterians. Fossil communities overlap temporally with the Avalon assemblage and are recognized in similar deep-water paleoenvironments. These results provide support for a hypothesized pattern of offshore origination followed by habitation of shallower environments through time, potentially unique to the early radiation of animals.

The rhopalium, an early specialized centralized nervous structure in medusozoans, exhibits a remarkable regenerative capacity after removal, offering a unique model for investigating the ancestral regulatory logic of neural regeneration. However, the cellular and molecular mechanisms underlying the process remain unknown. Here, we defined distinct stages of rhopalium regeneration in the jellyfish Aurelia coerulea and constructed a stage-specific cell landscape and gene regulatory networks. Notably, we identified a population of wound-induced cells that emerges rapidly postinjury and activates Wnt signaling to initiate blastema formation; cross-species comparisons revealed that this regulatory mechanism is conserved across metazoans. We further identified that retinoic acid signaling is essential for photoreceptor regeneration and ocelli reconstruction. The findings presented herein uncover the ancestral regulatory mechanisms governing neural regeneration in the early centralized nervous system, providing insights into the common evolutionary origins of neural repair across organisms.