Harsh Saline Research Articles

Alkali-Activated Binders as Sustainable Alternatives to Portland Cement and Their Resistance to Saline Water.

Alkali-activated binders have emerged as promising alternatives to Ordinary Portland Cement (OPC) due to their sustainability features and potential advantages. This study evaluates the durability properties of heat-cured fly ash (FA) and ground granulated blast-furnace slag (GGBFS) geopolymer mortars activated with sodium hydroxide, which were subjected to wet-dry cycling in saline environments. Three series of FA, a FA/GGBFS blend, and GGBFS mortars previously optimized on a compressive strength basis were investigated and compared against two control OPC mixes. Performance indicators such as the water absorption, porosity, flexural strength, and compressive strength were analyzed. The results demonstrate that geopolymer mortars have significantly reduced water absorption and porosity with increasing wet-dry cycles. The compressive strength of the FA/GGBFS mortars also increased from 66.5 MPa (untreated) to 87.9 MPa over 45 cycles. The flexural strength remained stable or improved slightly across all geopolymer mortars. The control OPC specimens experienced significant deterioration, with compressive strength in CEM I 42.5R dropping from 51.8 to 17.1 MPa. These findings highlight the superior durability of geopolymer mortars under harsh saline conditions, demonstrating their potential as a resilient alternative for coastal and marine structures.

Revolutionizing Tetracycline Hydrochloride Remediation: 3D Motile Light-Driven MOFs Based Micromotors in Harsh Saline Environments.

Traditional light-driven metal-organic-frameworks (MOFs)-based micromotors (MOFtors) are typically constrained to two-dimensional (2D) motion under ultraviolet or near-infrared light and often demonstrate instability and susceptibility to ions in high-saline environments. This limitation is particularly relevant to employing micromotors in water purification, as real wastewater is frequently coupled with high salinity. In response to these challenges, ultrastable MOFtors capable of three-dimensional (3D) motion under a broad spectrum of light through thermophoresis and electrophoresis are successfully synthesized. The MOFtors integrated photocatalytic porphyrin MOFs (PCN-224) with a photothermal component made of polypyrrole (PPy) by three distinct methodologies, resulting in micromotors with different motion behavior and catalytic performance. Impressively, the optimized MOFtors display exceptional maximum velocity of 1305±327µms-1 under blue light and 2357±453µms-1 under UV light. In harsh saline environments, these MOFtors are not only maintain high motility but also exhibit superior tetracycline hydrochloride (TCH) removal efficiency of 3578±510mgg-1, coupling with sulfate radical-based advanced oxidation processes and peroxymonosulfate. This research underscores the significant potential of highly efficient MOFtors with robust photocatalytic activity in effectively removing TCH in challenging saline conditions, representing a substantial advancement in applying MOFtors within real-world water treatment technologies.

Genome-wide comparative analyses highlight selection signatures underlying saline adaptation in Chilika buffalo.

Chilika, a native buffalo breed of the Eastern coast of India, is mainly distributed around the Chilika brackish water lake connected with the Bay of Bengal Sea. This breed possesses a unique ability to delve deep into the salty water of the lake and stay there to feed on local vegetation of saline nature. Adaptation to salinity is a genetic phenomenon; however, the genetic basis underlying salinity tolerance is still limited in animals, specifically in livestock. The present study explores the genetic evolution that unveils the Chilika buffalo's adaptation to the harsh saline habitat, including both water and food systems. For this study, whole genome resequencing data on 18 Chilika buffalo and for comparison 10 Murrah buffalo of normal habitat were generated. For identification of selection sweeps, intrapopulation and interpopulation statistics were used. A total of 709, 309, 468, and 354 genes were detected to possess selection sweeps in Chilika buffalo using the nucleotide diversity (θπ), Tajima's D, nucleotide diversity ratio (θπ-ratio), and FST methods, respectively. Further analysis revealed a total of 23 genes including EXOC6B, VPS8, LYPD1, VPS35, CAMKMT, NCKAP5, COMMD1, myosin light chain kinase 3 (MYLK3), and B3GNT2 were found to be common by all the methods. Furthermore, functional annotation study of identified genes provided pathways such as MAPK signaling, renin secretion, endocytosis, oxytocin signaling pathway, etc. Gene network analysis enlists that hub genes provide insights into their interactions with each other. In conclusion, this study has highlighted the genetic basis underlying the local adaptive function of Chilika buffalo under saline environment.NEW & NOTEWORTHY Indian Chilika buffaloes are being maintained on extensive grazing system and have a unique ability to convert local salty vegetation into valuable human food. However, adaptability to saline habitat of Chilika buffalo has not been explored to date. Here, we identified genes and biological pathways involved, such as MAPK signaling, renin secretion, endocytosis, and oxytocin signaling pathway, underlying adaptability of Chilika buffalo to saline environment. This investigation shed light on the mechanisms underlying the buffalo's resilience in its native surroundings.

Transcriptome analysis reveals the molecular mechanisms underlying the enhancement of salt-tolerance in Melia azedarach under salinity stress

Melia azedarach demonstrates strong salt tolerance and thrives in harsh saline soil conditions, but the underlying mechanisms are poorly understood. In this study, we analyzed gene expression under low, medium, and high salinity conditions to gain a deeper understanding of adaptation mechanisms of M. azedarach under salt stress. The GO (gene ontology) analysis unveiled a prominent trend: as salt stress intensified, a greater number of differentially expressed genes (DEGs) became enriched in categories related to metabolic processes, catalytic activities, and membrane components. Through the analysis of the category GO:0009651 (response to salt stress), we identified four key candidate genes (CBL7, SAPK10, EDL3, and AKT1) that play a pivotal role in salt stress responses. Furthermore, the KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway enrichment analysis revealed that DEGs were significantly enriched in the plant hormone signaling pathways and starch and sucrose metabolism under both medium and high salt exposure in comparison to low salt conditions. Notably, genes involved in JAZ and MYC2 in the jasmonic acid (JA) metabolic pathway were markedly upregulated in response to high salt stress. This study offers valuable insights into the molecular mechanisms underlying M. azedarach salt tolerance and identifies potential candidate genes for enhancing salt tolerance in M. azedarach.

Improved anticorrosive performance of epoxy coating by introducing a one-pot synthesised nano-ceria embedded lamellar polyaniline/kaolinite hybrid

This study presents an innovative and uncomplicated approach to produce ceria-decorated lamellar polyaniline utilising interfacial oxidative polymerisation, with ceric ammonium nitrate as both the aniline oxidiser and the ceria precursor. The study found that a 1 % weight of active polyaniline/ceria hybrid provides better corrosion protection. The addition of barrier kaolinite further enhances the protective properties of the hybrid. The study also proposes a mechanism for the synergistic function of ceria, polyaniline, and kaolinite in achieving better protective performance of the coating in harsh saline environments. The EIS results indicate that the cPAni_K/epoxy material shows a high |Z|0.01Hz value of 5.59 × 1010 and two months of continuous exposure, the charge transfer resistance maintained at 2.14 × 109 Ω cm2. EIS results exhibited the durability of the coating in the harsh saline media. Corrosion rate shows that cPAni_K embedded epoxy displays the corrosion rate of the eight-order lower than that of the pristine epoxy coat. This newly developed active/passive hybrid pigment is eco-friendly and suitable for preventing corrosion in marine environments.

DIV1: The master of awakening seeds in harsh salinity stress.

DIV1: The master of awakening seeds in harsh salinity stress.

Effect of Simulated Grazing on Morphological Plasticity and Resource Allocation of Aeluropus lagopoides

Aeluropus lagopoides, a dominant palatable species in various sabkha and coastal regions of Saudi Arabia, can withstand harsh saline environments through phenotypic plasticity. When subjected to grazing, how A. lagopoides adapt phenotypically is currently unknown. There is a breakage in the chain of study on the spatial and temporal expansion strategy of A. lagopoides plants when subjected to different grazing stresses in different saline soil habitats. A grazing experiment was conducted to investigate the phenotypic plasticity and resource allocation pattern response of A. lagopoides in different saline soils. Individual A. lagopoides rhizomes from five saline regions were grown and exposed to varied grazing treatments in the form of clipping, viz; light, moderate, and heavy grazing, as compared to a grazing exclusion control. Our results showed that heavy grazing/clipping significantly decreased the shoot system and above-ground biomass in high-saline region plants in the early season. Plant length, root length, root and shoot biomass, the number of stolons, average stolon length, leaf area, and SLA of A. lagopiodes responded significantly to grazing intensities. A. lagopoides from the Qareenah, Qaseem, and Jizan regions were more tolerant to light grazing than A. lagopoides from the Salwa and Jouf regions. Light grazing showed significantly good re-growth, especially during the late season. Light grazing decreased the synthesis of chlorophyll content. Also, A. lagopiodes reduced the risk caused by reactive oxygen species via the increased accumulation of proline content. Overall, plants adapted to different morphological and physiological strategies to tolerate different levels of grazing intensities by adapting their morphological attributes. Though heavy grazing damages the plant, light and moderate grazing can be allowed to maintain the productivity and economic benefits of sabka habitats where soil conditions are moderately saline.

Interaction of electrolyzed nanomaterials with sandstone and carbonate rock: Experimental study and DLVO theory approach

The utilization of nanoparticles (NPs) in various applications, such as water pollution treatment, CO2 geological storage enhancement, and enhanced oil recovery, holds great promise. However, the instability of NPs in fluidic environments severely limits their potential applications. Moreover, NPs tend to adsorb onto the surfaces of sandstones and carbonate rocks in high-saline environments, leading to formation damage. To enable large-scale implementation of NPs, comprehensive research is crucial to understand their stable behavior in harsh saline environments. This study focuses on investigating the interaction of electrolyzed synthesized nanomaterials, specifically titanium dioxide (TiO2), manganese oxide (Mn2O3), and graphene oxide (GO), with the surfaces of carbonate rock and sandstone. To characterize the nanomaterials, various techniques were employed, including Fourier transform-infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), Brunauer−Emmett−Teller (BET), x-ray diffraction (XRD), and field emission scanning electron microscopy (FE-SEM). TiO2, Mn2O3, and GO were synthesized using sol-gel, co-precipitation, and modified Hummer's methods, respectively. The stability of nanofluids was assessed through zeta potential and particle size measurements. The results revealed that the inner-sphere complexes formed by Ca2+ on GO NPs were more effective in neutralizing negative surface charges compared to Mg2+, resulting in a shift of the zeta potential towards lower absolute values. CaCl2 and MgCl2 were found to reverse the charges of Mn2O3 and TiO2 NPs (towards positive values), thus enhancing their stability at higher salt content. SEM images and ultraviolet–visible (UV–vis) spectroscopy measurements demonstrated that Mn2O3 and GO NPs were more prone to adsorption on rock surfaces when Ca2+ and Mg2+ ions were present in the nanofluids, respectively. To assess the interaction energies between NPs and surfaces and investigate the reversibility of NP adsorption, Derjaguin-Landau-Verwey-Overbeek (DLVO) analysis was conducted. The outcomes of this analysis were found to be consistent with the data obtained through SEM and UV–vis spectroscopy.

Non‐Noble Bifunctional Amorphous Metal Boride Electrocatalysts for Selective Seawater Electrolysis

AbstractThe global scarcity of freshwater resources has recently driven the need to explore abundant seawater as an alternative feedstock for hydrogen production by water‐splitting. This route comes with new challenges for the electrocatalyst, which has to withstand harsh saline water conditions with selectivity towards oxygen evolution over other competing reactions. Herein, a series of amorphous metal borides based on the iron triad metals (Co, Ni, and Fe), synthesized by a simple one‐step chemical reduction method, displayed excellent bifunctional activity for overall seawater splitting. Amongst the chosen catalysts, amorphous cobalt boride (Co−B) showed the best overpotential values of 182 mV for HER and 305 mV for OER, to achieve 10 mA/cm2, in alkaline simulated seawater. This superior activity was owed to the enrichment of the metal site with excess electrons (HER) and the in‐situ surface transformation (OER), as confirmed by various means. In alkaline simulated seawater, the overall cell voltage required to achieve 100 mA/cm2 was 1.85 V for the Co−B catalyst when used in a 2‐electrode assembly. The Co−B catalyst showed negligible loss in activity even after 1000 cycles and 50 h potentiostatic tests, thus demonstrating its industrial viability. The selectivity of the catalyst was established with Faradaic efficiency of above 99 % for HER and 96 % for OER, with no detection of chloride products in the spent electrolyte. This study using the mono‐metallic boride catalysts will turn to be a precursor to exploit other complex metal boride systems as potential candidates for seawater electrolysis for large‐scale hydrogen production.

An Anti-Fracture and Super Deformable Soft Hydrogel Network Insensitive to Extremely Harsh Environments.

Design of hydrogels with superior flexible deformability, anti-fracture toughness, and reliable environment adaption is fundamentally and practically important for diverse hydrogel-based flexible devices. However, these features can hardly be compatible even in elaborately designed hydrogels. Herein soft hydrogel networks with superior anti-fracture and deformability are proposed, which show good adaption to extremely harsh saline or alkaline environments. The hydrogel network is one-step constructed via hydrophobic homogenous cross-linking of poly (sodium acrylate), which is expected to provide hydrophobic associations and homogeneous cross-linking for energy dissipation. The obtained hydrogels are quite soft and deformable (tensile modulus: ≈20kPa, stretchability: 3700%), but show excellent anti-fracture toughness (10.6kJm-2 ). The energy dissipation mechanism can be further intensified under saline or alkaline environments. The mechanical performance of the hydrophobic cross-linking topology is inspired rather than weakened by extremely saline or alkaline environments (stretchability: 3900% and 5100%, toughness: 16.1 and 17.1kJm-2 under saturated NaCl and 6molL-1 NaOH environments, respectively). The hydrogel network also shows good performance in reversible deformations, ion conductivity, sensing strain, monitoring human motions, and freezing resistance under high-saline environments. The hydrogel network show unique mechanical performance and robust environment adaption, which is quite promising for diverse applications.

Molecular insight into the effect of the number of introduced ethoxy groups on the calcium resistance of anionic-nonionic surfactants at the oil/water interface

The salinity seriously affects the recovery efficiency of surfactant flooding, and it is demonstrated the introduced ethoxy (EO) groups can enhance the interfacial activity of surfactants at harsh salinity via various experimental methods. In this study, sodium dodecyl sulfate (SDS) and sodium dodecyl ether sulfate (AES) are selected to investigate the effects of EO group number on the salt resistance of surfactants at the air/water interface by experiments and molecular dynamics (MD) simulation method. Optical microscopy and static multiple light scattering results show that the AES stabilized emulsions with Ca2+ ions have better stability than those of SDS, which is further explored by molecular MD simulation method. The interface formation energy (IFE) and self-diffusion coefficients (Dα) are calculated to systematically study the effects of introduced EO group number on calcium resistance of surfactants. The interaction between surfactants and Ca2+ ions at the oil/water interface is evaluated by the potential of mean of force (PMF) and the radial direction functions (RDF), which is confirmed by the calculation of molecular electrostatic potential (MEP) and coordination number. The simulation results indicate that the introduced EO groups can combine Ca2+ ions to fabricate salt bridge via intermolecular or intramolecular interactions to highly improve the calcium resistance of surfactants. The present work proposes a microcosmic perspective of the roles of EO group number on the calcium resistance of AES at the oil/water interface.

Hydrothermal Stability and Transport Properties of Optically Detectable Advanced Tracers With Carbonate Rocks in the Presence of Oil

Summary The use of tracer technology to illuminate reservoir characteristics such as well connectivity, volumetric sweep efficiency, and geological heterogeneity for the purpose of improving history-matching fidelity and enriching production optimization algorithms has gained momentum over the last decade. Herein, we report the stringent laboratory qualification of a novel class of fluorescent molecules, optically detectable down to ultratrace levels (<ppb) in produced water, as competent crosswell water tracers for use in highly retentive carbonate reservoirs with harsh salinity and temperature requirements. Tracer molecules, with state-of-the-art fluorobenzoic acids (FBAs) as a benchmark, exhibiting requisite hydrothermal stability and nonretentive behavior in simulated reservoir conditions coreflood tests are scheduled to be field-trialed. Our novel fluorescent tracer material systems, based on dipicolinic acid (DPA) and naphthalene sulfonates, rely on time-resolved luminescence and/or advanced chromatographic separation to eliminate the interfering fluorescent background issue in produced water for near real-time analysis. We systematically evaluated the novel tracer molecules at 95°C in high-salinity injection brine over 4 months, with periodic sampling and analysis by liquid chromatography to ascertain their hydrothermal stability. Coreflood tests at reservoir conditions were conducted to determine their interactions with carbonate rock surfaces with and without residual crude oil. All qualification tests were performed using a reference water tracer 2-FBA and/or a model partitioning tracer 4-chlorobenzyl alcohol as benchmark. Finally, reservoir simulations were performed to study both nonpartitioning and partitioning tracer transports in realistic field conditions. Hydrothermal stability tests indicated that our novel tracers are stable for 132 days in brine under reservoir conditions. Coreflood tests without residual oil revealed that the novel fluorescent tracer materials, such as FBAs, exhibit negligible retention in carbonate rocks (almost 100% recovery of the tracers). Coreflood experiments with residual oil suggested that all tracer materials, including the FBAs, possibly reversibly interact with the rocks, resulting in lower tracer materials recovery. While the overall retention of tracer materials is minimal in the presence of residual oil, these values were found to be relatively higher to that measured without residual oil. We observed no significant change in core permeability due to tracer injection. Field-scale reservoir simulation sensitivity studies in companion with coreflood experiments indicated minimum interferences for consecutive tracer injections in the field trial settings. We believe this is the first time such direct comparative study has been performed in the existing research to evaluate the interaction of both water and partitioning tracers in carbonate rocks at reservoir conditions with and without the presence of residual crude oil. Reducing the burden of analysis is critical in the implementation of this technology to obtain high-fidelity tracer data that can be used to improve waterflood optimization, increasing hydrocarbon recovery by a few percent per well without using additional resources for drilling or production. The ability to use presently commercialized tracer technologies, such as FBA-based molecules, in conjunction with this novel optically detectable fluorescent tracer platform will be a force multiplier to enable large tracer campaigns that provide high-fidelity tracer data for a production optimization algorithm.

Effect of benomyl-mediated mycorrhizal association on the salinity tolerance of male and monoecious mulberry clones

Mulberry is an economically important crop for sericulture in China. Mulberry plantations are shifting inland, where they face high salinity. Arbuscular mycorrhizal fungi (AMF) reportedly enhance mulberry's tolerance to salinity. Here, we assessed if additional adaptive advantages against salinity are provided by sex differences beyond those provided by mycorrhizal symbiosis. In a pot experiment, male and monoecious plants were exposed to three salinity regimes (0, 50, and 200 mM NaCl) and two mycorrhiza-suppressed conditions (with or without benomyl application) for more than 16 months. We noticed that salinity alone significantly decreased the mycorrhizal colonization rate, salinity tolerance, K+ concentrations, and the ionic ratios of all plants. Mycorrhizal association mildly ameliorated the salt-induced detrimental effects, especially for monoecious plants, and sex-specific responses were observed. Meanwhile, both sexes had adopted different strategies to enhance their salinity resistance. Briefly, mycorrhizal monoecious plants exhibited a higher net photosynthetic rate and lower translocation of Na+ from root to shoot compared with mycorrhizal males under saline conditions. Their salt tolerance was probably due to the Ca2+/Na+ in roots. In comparison, male plants exhibited lower Na+ acquisition, more Na+ translocated from root to shoot, higher root biomass allocation, and higher N concentrations under harsh saline conditions, and their salt tolerance was mainly related to the K+/Na+ in their shoots. In conclusion, our results highlight that AMF could be a promising candidate for improving plant performance under highest salinity, especially for monoecious plants. Cultivators must be mindful of applying fungicides, such as benomyl, in saline areas.

Anatomical and physiological systematics of Capparis decidua (Forsskal.) Edgew from different habitats of Cholistan Desert, Pakistan

Capparis decidua a medicinal shrub belonging to the family Capparaceae, grows abundantly in wild regions of Asia, Africa, and Saudi Arabia. Due to its medicinal and nutritional value, a study on anatomical and physiological adaptations under various desert habitats was conducted. Results revealed that plants in saline areas showed significant anatomical and physiological modifications particularly in stem and roots show better survival under the harsh saline conditions of the desert. It was noted that the root epidermis thickness was not affected in a slightly saline environment as it showed no significant increasing or decreasing trend in the cross-section of the plant population from non-saline to slightly saline (p > 0.05) while it increased significantly in plants growing at highly saline (p < 0.05). Whereas endodermis cell area differs significantly between plants growing at all selected study sites it increased continuously with a rise in the salinity level of the soil (p < 0.05). Meanwhile, water storage capacity and reduction of water loss in the stem area, epidermis, and sclerenchyma were also recorded. In a highly saline environment, results intimate the deduction of photosynthetic pigments, an increase in total soluble proteins, total free amino acids, total soluble sugars, and proline, and a rise in stem and root tissue Na+, K+, Ca2+, and Cl− contents and meanwhile, accumulation of secondary metabolites (Phenolics and flavonoids). These anatomical and physiological adaptations in natural populations appear to be very important for their better survival in a harsh saline desert environment. It was concluded that C. decidua was found in all different edaphic habitats of the Cholistan Desert, due to its adaptive features, which were very obvious in this plant and highly saline site.

Comparative metabolomics unveils the role of metabolites and metabolic pathways in the adaptive mechanisms of shrubby halophytes

Salinity is a major abiotic stress that reduces agricultural production by impairing crop growth and development. Halophytes can complete their life cycle under high salinity conditions. In this study, primary metabolic pathways and metabolic marker were compared in three halophytes; Atriplex nummularia , A . griffithii and Salvadora persica . The principal component analysis (PCA) and partial least squares-discriminate analyses (PLS-DA) identified variations among halophytes. Furthermore, correlation analyses, metabolites network analyses and pathway impact/enrichment analyses revealed common metabolic pathways occurring in halophytes. Unequivocally, a total of 49 metabolites were identified from different metabolites classes such as amino acids, sugars, sugar alcohols (SAs), organic acids, and tricarboxylic acid cycles. The metabolic differences were noted for serine, norvaline, threonic acid, glucose, sucrose, mannitol, galactinol, and glycerol in S . persica as compared to Atriplex spp. The TCA cycle metabolites malic and citric acids were majorly found in A . nummularia , while succinic and 2-ketoglutaric acids were detected in A . nummularia and S . persica . Correlation-based networking and KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway enrichment analysis revealed linkages of metabolites to major biological pathways like amino acid (AA) biosynthesis, carbohydrate metabolism, glyoxylate and dicarboxylate metabolism, arginine biosynthesis, galactose metabolism, butanoate metabolism, and the TCA cycle. The current work is the first to report on the metabolomic responses of shrubby halophytes in natural environmental conditions. The study’s findings, especially the coordination of multiple metabolic processes and pathways in shrubby halophytes, clarify how the plant adapts to harsh saline environments. All datasets are included in the article and supplementary data . • Metabolic pathways and metabolic marker were compared in three shrubby halophytes. • A total of 49 metabolites were identified from different functional classes. • Study revealed linkages of metabolites to major biological pathways. • First report on metabolomic-responses of shrubby-halophytes in natural environment. • Study unveils role of metabolomic-pathways in adaptive-mechanisms of shrubby-halophytes.

Design and synthesis of a new ionic liquid surfactant for petroleum industry

This study is intended to synthesize and assess a new pyridinium-based Ionic Liquid (IL) surfactant, 1-octadecyl-pyridinium bromide, in terms of crude oil–water Interfacial Tension (IFT) reduction and wettability alteration. The synthesized IL surfactant is firstly characterized through proton Nuclear Magnetic Resonance (1H NMR). Then, the pendant-drop and sessile drop techniques are employed to study crude oil–water IFT and the wettability of carbonate rocks. Based on the IFT results, the synthesized IL has a Critical Micelle Concentration (CMC) of 200 ppm, at which crude oil–water IFT reduces by 95.9 %, from an initial value of 23.7 mN/m to 0.97 mN/m. Increasing the salinity up to 100,000 ppm could not make the synthesized IL less effective than that of free from salinity, as the magnitude of IFT is obtained to be 0.938 mN/m at CMC. Based on the wettability investigation phase, the synthesized IL changes the wettability of carbonate slices from oil-wet to intermediate-wet (140.47°–90.97°). It is also observed that the synthesized IL can tolerate harsh salinity conditions as no appreciable change in the contact angle is noticed after increasing the salinity even up to 150,000 ppm (84.54° at CMC). It should be noted that an optimal salinity of 50,000 ppm is found based on the results of IFT and contact angle measurements. The introduced surfactant is expected to exhibit a significant positive impact on the oil recovery factor while implementing chemical flooding.

Rheology and Injectivity Studies on Scleroglucan Biopolymer for Carbonates under Harsh Conditions

Summary Polymer flooding is a mature chemical enhanced oil recovery (EOR) technology with more than 40 years of laboratory- and field-scale applications. Nevertheless, polymers exhibit poor performance in carbonates owing to their complex nature of mixed-to-oil wettability, high temperature, high salinity, and heterogeneity with low permeability. The main objective of this study is to experimentally evaluate the performance of a potential biopolymer (scleroglucan) in carbonates under harsh conditions of high temperature and high salinity. This experimental investigation includes polymer rheological studies as well as polymer injectivity tests. Rheological studies were performed on the biopolymer samples to measure the polymer viscosity as a function of concentration, shear rate, salinity, and temperature. Injectivity characteristics of this biopolymer were also examined through single-phase corefloods using high permeability carbonate outcrops. The injectivity tests consisted of two stages of water preflush and polymer injection. These tests were conducted using high salinity formation water [167,000 ppm total dissolved solids (TDS)] and seawater (43,000 ppm TDS) at both room (25°C) and high temperature (90°C) conditions. The rheological tests showed that the biopolymer has a high viscosifying power, and it exhibits a shear-thinning behavior that is more prevalent at higher polymer concentrations. Also, a pronounced effect was observed for water salinity on both polymer filterability and injectivity. Moreover, the biopolymer exhibited better filterability at the high temperature as opposed to the room temperature. From the injectivity tests, the shear-thinning behavior of this biopolymer in the porous media was confirmed as the resistance factor (RF) decreased with increasing the flow rate applied. The potential biopolymer showed good injectivity at both the room and the high temperatures. A limited number of studies have evaluated the rheological and injectivity performance of this newly developed EOR grade scleroglucan biopolymer in carbonates under harsh conditions of high salinity and high temperature. Most of the previous studies were performed in sandstones under relatively mild salinity and temperature conditions. Hence, this study provides further insight into the performance of this biopolymer and encourages application in carbonates under harsh salinity and temperature conditions.

Getting to the root of the problem: improving measurements of mangrove belowground production and carbon sequestration.

This article is a Commentary on Arnaud et al. (2021), 232: 1591–1602.

Differential Responses of Dimorphic Seeds and Seedlings to Abiotic Stresses in the Halophyte Suaeda salsa.

The period between seed germination and seedling establishment is one of the most vulnerable stages in the life cycle of annuals in the saline environments. Although germination characteristics of Suaeda salsa seeds have been reported, the comparative germination patterns of dimorphic seeds and seedling growth to different abiotic stresses remain poorly understood. In this study, germination responses of dimorphic seeds to light and temperature were compared. Meanwhile, responses of dimorphic seeds and thereafter seedlings of S. salsa to different concentrations of NaCl and Na2SO4 were also tested. The results showed that the light did not significantly affect germination percentage of brown seeds, but significantly promoted germination of black seeds. Brown seeds could reach high germination percentage over a wide temperature range, however, germination of black seeds gradually increased with the increase of temperature. Brown seeds had higher germination percentage and velocity than black seeds under the same salt conditions. However, black seeds had higher recovery germination than brown seeds when transferred to deionized water. Young seedlings had lower salt tolerance than germinating seeds. At the same concentrations, Na2SO4 had stronger inhibitory effect on seed germination and seedling growth than NaCl. This study comprehensively compared germination traits of dimorphic seeds and seedling growth of S. salsa, and then developed a conceptual model to explain their adaptation to harsh saline environment.

When Salt Meddles Between Plant, Soil, and Microorganisms.

In extreme environments, the relationships between species are often exclusive and based on complex mechanisms. This review aims to give an overview of the microbial ecology of saline soils, but in particular of what is known about the interaction between plants and their soil microbiome, and the mechanisms linked to higher resistance of some plants to harsh saline soil conditions. Agricultural soils affected by salinity is a matter of concern in many countries. Soil salinization is caused by readily soluble salts containing anions like chloride, sulphate and nitrate, as well as sodium and potassium cations. Salinity harms plants because it affects their photosynthesis, respiration, distribution of assimilates and causes wilting, drying, and death of entire organs. Despite these life-unfavorable conditions, saline soils are unique ecological niches inhabited by extremophilic microorganisms that have specific adaptation strategies. Important traits related to the resistance to salinity are also associated with the rhizosphere-microbiota and the endophytic compartments of plants. For some years now, there have been studies dedicated to the isolation and characterization of species of plants’ endophytes living in extreme environments. The metabolic and biotechnological potential of some of these microorganisms is promising. However, the selection of microorganisms capable of living in association with host plants and promoting their survival under stressful conditions is only just beginning. Understanding the mechanisms of these processes and the specificity of such interactions will allow us to focus our efforts on species that can potentially be used as beneficial bioinoculants for crops.