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Observations on the Biology and Fishery of the Marbled Spinefoot (Siganus rivulatus Forsskål & Niebuhr, 1775) in the Eastern Red Sea
No full textThis study aims to enhance our understanding of the marbled spinefoot (Siganus rivulatus) population along the Red Sea coast of Saudi Arabia. It investigates whether the stock is subject to overfishing and tests the hypothesis that current fishing mortality exceeds sustainable thresholds. A total of 6192 specimens were sampled during a comprehensive survey conducted from 2022 to 2024, utilizing a range of fishing methods, including handline, trap, gillnet, and demersal trawl fisheries. The sampled fish ranged in total length (TL) from 100 to 335 mm and in total weight (W) from 17 to 470 g. The length–weight relationship was W = 0.0175 × TL2.92. Growth parameters derived from the von Bertalanffy model were TL∞ = 43.5 cm, K = 1.12 year−1, and t0 = −0.18 year. The median size at first maturity was estimated at 14.83 cm TL for both sexes. Virtual Population Analysis revealed fishing mortality rates ranging from 0.01 year−1 to 0.89 year−1 across age classes 1 to 5 years, with exploitation levels of 0.6, 0.55, and 0.5 at ages 3, 4, and 5, respectively, indicating slight overfishing. The annual average catch of marbled spinefoot along the Saudi Arabian Red Sea coast was approximately 211 tonnes, contributing an estimated 1.8 million USD to the national economy. Maintaining the current fishing effort at sustainable levels is essential to ensure the long-term viability of this stock.The authors thank the Ministry of Environment, Water, and Agriculture of Saudi Arabia for funding this research project on the assessment of major fish stocks in the Red Sea waters of the Kingdom. They are also grateful to their colleagues at the KAUST Beacon Development Fisheries Program for their assistance and support during the fieldwork, and Nazli Demirel for her help during the preparation of the manuscript
Empirical rate rules for hydroxyl radical reactions with alkenes
No full textAlkenes are not only constituents of practical fuels but are also key intermediates of the oxidation and pyrolysis of larger hydrocarbons. The interactions between alkenes and hydroxyl (OH) radicals play a pivotal role in the depletion of alkenes. Literature measurements of OH + alkene reactions have been limited to small molecules containing fewer than seven carbon atoms. Moreover, the competition between various channels in these reactions remains poorly understood. Here, we studied channel-specific rate coefficients of propene + OH and combined it with literature measurements to derive rate rules for alkene + OH reactions. This work presents the first direct measurement of the channel-specific rate coefficients (k1a) for the reaction of OH + propene → allyl radical + H2O. Using a sensitive UV absorption diagnostic scheme at 220 nm, we tracked the time-resolved formation of the product allyl radical. Our determined rate coefficients are described by the following Arrhenius expression (unit: cm3molecule-1s-1):
(900–1200 K)
Between 900 and 1200 K, the H abstraction from allylic Csingle bondH bonds of propene accounted for 55 - 65 % of the overall reactivity and exhibited a gentle positive temperature dependence.
Our investigation of hydroxyl reaction with propene serves as a prototype reaction of a molecule containing allylic Csingle bondH bonds. In conjunction with literature-reported rate coefficients of OH + C4 – C6 alkenes, we propose a set of rate rules encompassing vinylic, alkylic, and allylic Csingle bondH bonds. These rate rules could be used to predict the behavior of large alkene reactions with OH when direct measurements and calculations are not available. Notably, our rate rules revealed that the primary allylic Csingle bondH bonds in propene and iso-butene react with about a 40 % slower rate with OH than the primary allylic Csingle bondH bonds in 2-alkenes, cautioning against direct analogy between the rate coefficients of these Csingle bondH bonds. Additionally, the secondary allylic Csingle bondH bonds in a trans-2-alkene molecules are 33 % more efficient in consuming OH radicals than those in the cis-2-alkenes.
These rate rules are incorporated in literature models of alkenes and biofuels containing similar Csingle bondH bonds, thus enabling improved accuracy of model predictions. Our work provides new insights into the channel-specific competition of OH + alkene reactions, and benefits automated modeling of alkene molecules and double-bond containing biofuelsResearch reported in this publication was funded by King Abdullah University of Science and Technology (KAUST)
The Enterobacter sp. SA187 stimulates stress-responsive genes and promotes salt and heat stress tolerance in tomato plants
No full textEnterobacter sp. SA187, is a plant growth-promoting bacterium (PGPB) with potential to enhance abiotic stress tolerance in various crops. This study evaluated the impact of inoculation of SA187 to salinity and heat stress tolerance of Solanum lycopersicum L, tomato. Different alterations in the physiological, biochemical and molecular responses against the salt and heat stress due to the beneficial association of tomato plants with SA187 were investigated. Colonization by SA187 significantly enhanced tomato plants growth under both saline and heat stress condition. It induced an enhancement of > 90 % in the morphological and physiological processes resulting in an increased root hair growth and higher plant biomass. The inoculation also caused a 65 % decline in Na+/K+ ratio, increased chlorophyll content and improved the antioxidant enzyme activity of Superoxidase dismutase (SOD), Peroxidase (POD), and Catalase (CAT), particularly under salt and heat stress conditions. The RNA-seq analysis produced clean reads that ranged from 33,812,161 to 44,114,539 across the different groups of treatment, which were successfully assembled into 35,825 annotated genes. Transcriptomic analysis of the genes involved in the enhancement of the physiological and biochemical processes revealed at least a 2-fold increase in the expression of NHX3 and ERF4 in leaves, SOS2, SOS4, and SULTR3;5 in leaves and roots. For heat stress, SA187-colonized tomato plants displayed higher expression of heat shock protein genes in leaves such as HSP17.4B, HSP17.6, HSP22.0, and HSP26.5. These findings show the possibility of using the Enterobacter sp. SA187 as a sustainable solution for enhancing crop tolerance and productivity in challenging environmental conditions.This research was supported by funding from the United Arab Emirates University Horticulture Master program grant (#270F00) to KM
Deep oxygen-depleted depressions in a Red Sea coral reef sustain resistant ecosystems
No full textPersistent oxygen-depleted zones in the ocean are known primarily from enclosed basins in temperate regions or the open ocean (including oxygen minimum and limiting zones) (1). However, little is known about the possibility of such zones forming in tropical coastal domains, even though the combination of warmer temperatures and complex geological features in some tropical regions makes their occurrence more likely (1, 2). Here, we report two subsurface oxygen-depleted zones within deep (>490 m) depressions of the Red Sea's Difaht Farasan—a carbonate platform hosting the world's third largest contiguous tropical coral reef system. One zone maintains suboxic oxygen levels (∼11–14 µmol O2 kg⁻¹), while the other sustains oxygen levels below detection (21 °C). Targeted exploration of deep tropical coastal environments is crucial for determining whether similar zones exist beyond the Red Sea and understanding their potential responses to climate change.The authors thank the National Center for Wildlife (NCW, Kingdom of Saudi Arabia) for the invitation to participate in the RSDE22. The authors thank the staff of the NCW and R/V OceanXplorer for their operational and logistical support during the campaign. All data and images collected during the RSDE22 are credited to the NCW. The authors also thank J.P. Gattuso, Y. Khaled, C. Roch, V. Dighe, V. Dasari, C. Fu, and staff from the Coastal Marine Resources Core Lab of KAUST for their expert advice and technical support.The RSDE was funded by the National Center for Wildlife (NCW, Kingdom of Saudi Arabia). King Abdullah University of Science and Technology (KAUST) also supported this research through baseline funding awarded to C.M.D and F.B
Changes in the Top-Down Control of Planktonic Bacteria in Response to Nutrient Addition and Warming in the Red Sea
No full textEutrophication and warming impacts on marine bacterioplankton and their top-down controls (protistan grazers and viruses) are still little known. Here, we evaluated the seasonal variability of the joint impact of nutrient addition and temperature on the abundance of bacterioplankton, heterotrophic nanoflagellates (HNFs) and viruses in Red Sea coastal waters. We conducted four microcosm experiments in which samples were either incubated as such (control, C) or amended with phosphate and nitrate (inorganic, I), glucose (organic, O) or both types of nutrients (mixed, M). Each nutrient treatment was incubated at three temperatures spanning 6°C around ambient values (23°C–33°C). Microbial response ratios (RR, the ratio between the maximum abundance in each nutrient amendment treatment relative to the maximum abundance in the C treatment) were variable, with the most noticeable increases found in the I and M treatments, suggesting an effect mediated by increased primary production. Bacterioplankton showed weak responses to warming, but the RRs of HNFs and viruses in the I treatment tended to increase at higher temperatures. The response of HNFs to the increase in prey was stronger than that of viruses. Our results also suggest that the coupling between heterotrophic bacteria and HNFs will likely increase with future warming.We gratefully acknowledge Tamara M. Huete- Stauffer and MiguelViegas who contributed to the field and lab work. This manuscript orig-inated from E.I.S. doctoral dissertation, supported by the baseline fund-ing of King Abdullah University of Science and Technology to X.A.G.
Overcoming Challenges for the Carbon Credit Market In Saudi Arabia To Reduce Carbon Emissions
No full textSaudi Arabia is advancing ambitious decarbonization targets under Vision 2030 while maintaining its role as a global energy producer. Expanding renewable energy and engaging in the Voluntary Carbon Market (VCM) are central to reducing emissions and diversifying the national energy portfolio. Yet, the contribution of large-scale renewable projects to carbon offset generation remains underexamined. This study evaluates three flagship projects the NEOM Green Hydrogen Project, Dumat Al-Jandal Wind Farm, and Sakaka Solar Power Plant to assess their potential for carbon mitigation and alignment with Saudi Arabia’s climate commitments. Projects were selected based on technology type, scale, and data availability. Installed capacity, annual generation, and estimated CO₂ avoidance were compiled from developer reports and international databases. Emission factor calculations were applied, with results presented through GIS mapping to highlight geographic advantages and comparative charts to illustrate performance.
Results indicate that NEOM demonstrates the highest offset potential, at 2.37 million tonnes of CO₂ annually, compared with 674,000 tonnes for Dumat Al-Jandal and 361,000 tonnes for Sakaka. The findings highlight the decisive role of project type and scale in determining mitigation outcomes. Large-scale integrated projects, particularly green hydrogen, are positioned to enable Saudi Arabia to generate voluntary carbon credits, strengthen its role in global carbon markets, and advance engineering-driven climate solution
Modelling coupled Thermo-Hydro-Mechanical processes in variably saturated porous media
No full textSimulating Thermo-Hydro-Mechanical (THM) problems in variably saturated porous media presents significant challenges due to the high nonlinearity of the coupled processes, and the numerical instabilities that may lead to nonphysical oscillations in pressure, stress, and temperature solutions. In this work, a robust Mixed Finite Element (MFE) scheme based on the lowest order Raviart-Thomas space is developed for the THM problem in deformable unsaturated porous media. The MFE method for fluid flow and heat transport is integrated with the Crouzeix-Raviart (CR) finite element method for the displacement field. To prevent nonphysical oscillations induced by the hyperbolic convection term in the heat transport equation, the MFE method incorporates an upwind scheme. The Method of Lines (MOL) is employed to transform the partial differential equations into a system of nonlinear ordinary differential equations integrated in time with high-order methods using the DASPK time solver. The coupled THM equations are solved simultaneously using a monolithic scheme to avoid splitting errors. The primary unknowns of the developed formulation are the hydraulic head, the temperature, and the displacement vectors that are assigned at the mesh edges. The proposed MFE models are implemented using Fortran code and developed for both poroelasticity and thermo-poroelasticity problems. The developed models are validated by comparisons against analytical and standard finite element solutions for classical benchmarks. Several numerical experiments are performed under saturated and unsaturated conditions to show the efficiency and accuracy of the developed model. The robustness of the proposed MFE model is demonstrated by solutions free of oscillations. Furthermore, a two-phase THM model is established with COMSOL Multiphysics to investigate the CO2 plume evolution and the reservoir stability during the CO2 injection into the sealed Unayzah formation in Saudi Arabia and highlight the application of the THM model in CO2 sequestration field
Transcriptome-based meta-analysis of drought stress regulatory genes in tomato.
No full textPlants possess various molecular defense systems to ward off biotic and abiotic stresses and adjust to environmental changes. The RNA-seq technology assists biologists in quickly identifying genes responding to abiotic stresses. Thereby, using meta-transcriptomic data from the GEO NCBI public database, we have attempted to reach a consensus on gene variations. This approach identified a global set of 18 drought-responsive genes by Bonferroni-adjusted proportional test on one sample, p 2 (biological process), XH/XS domain-containing protein (molecular function & cellular component), alpha 1,4-glycosyltransferase family protein (KEGG) and Histone superfamily protein (plant ontology). qRT-PCR-based gene expression analyses elaborated the similar trends in gene expression in both local genotypes under drought stress conditions covering the ratio of six to four as per down and upregulated meta-genes, respectively. This could indicate that these genes are part of a putative set of stress-responsive genes that are crucial for survival and adaptation under drought conditions thereby, they may serve as potential targets for future functional studies and breeding applications that will be helpful to enhance tomato production in the future.The NIGAB, Pakistan, provided research facilities that the authors gladly acknowledge.
The funding for this study was provided by NIGAB out of the Sino-Pak project (857)
Reconfigurable All-Nitride Magneto-Ionics.
No full textThe rapid advancement of generative artificial intelligence has significantly increased the demand for both energy and data storage. Magneto-ionics, which utilizes ionic motion to control magnetism, often driven by an electric field in heterostructures, has gained significant attention for its potential to enable energy-efficient modulation of magnetic properties with large effects. This study proposes a CMOS-compatible solid-state magneto-ionic system composed of all-Mn-nitrides and demonstrates that nitrogen ionic motion can induce reversible phase transitions between ferrimagnetic and antiferromagnetic Mn nitrides. This magnetic phase transition is manifested in dramatic changes in the resultant exchange bias effect, which can be increased by over an order of magnitude when more nitrogen is introduced into the nitrides during deposition and subsequently reduced by over 70% when nitrogen is taken out of the nitrides through post-annealing. Additionally, voltage-induced nitrogen ionic motion can lead to reversible changes in saturation magnetization and the exchange bias effect by 23% and 0.1 T (16%) at 5 K, respectively. These findings highlight the characteristics of this all-Mn-nitride system as an industrially viable and environmentally sustainable platform, offering tunable magnetic properties and energy-efficient operation and potential for magnetic field immunity.This work was supported in part by the NSF (DMR-2005108, ECCS-2151809, ECCS-2132098), AFOSR (FA9550-23-1-0497), and KAUST (OSR-2019-CRG8-4081). The acquisition of a Quantum Design Magnetic Property Measurements System (MPMS3), which was used in this investigation, was supported by the NSF-MRI program (DMR-1828420)
A Skin-Adherent Magneto-Inertial Wearable for Real-Time Joint Motion Analysis
No full textMusculoskeletal physiotherapy is evolving with the integration of wearable technologies that enable continuous monitoring and personalized rehabilitation. This study presents a multimodal, wireless, and cost-effective wearable system designed to assess and classify joint motion using magneto-inertial sensing. The system incorporates a flexible PDMS-NdFeB magnetic skin patch and a compact sensor module with a 9-degree-of-freedom IMU. Real-time joint kinematics are wirelessly transmitted to a custom mobile application, enabling interactive visualization and feedback. Biomechanical modeling is employed to evaluate muscle contributions and joint dynamics across the wrist, elbow, and knee. Processed magnetic signals are used to classify range of motion (ROM) into three categories—Limited, Normal, and Hypermobility—through traditional machine learning and deep learning models. A 1D convolutional neural network (1D-CNN) achieves the highest classification accuracy (95.3%). The proposed system demonstrates strong potential for enhancing musculoskeletal rehabilitation by providing accurate, real-time assessments and individualized treatment feedback.The research reported in this publication was supported by funding from the KAUST – Center of Excellence on Smart Health, under award number [5932] and SPARK: Social and the Personal Adaptive Response Kit – Igniting Child Development with AI and Sensor Technology under award number [6565]