In the context of climate change, salinity intrusion into rivers has been, and will be, one of the most important issues for coastal water resources management. A combination of changes, including ...increased temperature, change in regional rainfall, especially sea level rise (SLR) related to climate change, will have significant impacts on this phenomenon. This paper presents the outcomes of a study conducted in the Mekong Delta of Vietnam (MKD) for evaluating the effect of sea water intrusion under a new SLR scenario. Salinity intrusion was simulated by one-dimensional (1D) modeling. The relative sea level projection was constructed corresponding to the RCP 6.0 emission scenario for MKD based on the statistical downscaling method. The sea level in 2050 is projected to increase from 25 cm to 30 cm compared to the baseline period (in 2000). Furthermore, the simulated results suggested that salinity greater than 4 g/l, which affects rice yield, will intrude up to 50-60 km into the river. Approximately 30,000 ha of agricultural area will be affected if the sea level rise is 30 cm.
Controlling water salinity plays a key role in farming efficiency. Current sensors are mostly expensive and need regular maintenance. In addition, they require electrical connections or extra power ...supply that leads to difficult and costly implementation in remote-sensing scenarios. In this article, an accurate and low-profile sensor is developed using a metamaterial perfect absorber (MPA) structure. The proposed sensor works based on the level and frequency of the absorbed signals. Hence, there is no need for electrical connections, which enables remote-sensing applications. Square-shaped channels have been created in a regular FR-4 substrate to facilitate sensing of water salinity levels. A <inline-formula> <tex-math notation="LaTeX">7 \times 7 </tex-math></inline-formula> array with a total size of <inline-formula> <tex-math notation="LaTeX">140 \,\,\text {mm} \times 160 \,\,\text {mm} </tex-math></inline-formula> has been fabricated that shows a resolution of 10 MHz per percentage of water salinity. The absorption frequency shifts from <inline-formula> <tex-math notation="LaTeX">f=3.12 </tex-math></inline-formula> to 3.59 GHz for salinity level from 0% to 50%. A strong correlation between measurement and simulation results validates the design procedure.
Today, salinity stress is one of the most important abiotic stresses in the world, because it causes damage to many agricultural products and reduces their yields. Oxidative stress causes tissue ...damages in plants, which occurs with the production of reactive oxygen species (ROS) when plants are exposed to environmental stresses such as salinity. Today, it is recommended to use compounds that increase the resistance of plants to environmental stresses and improve plant metabolic activities. Salicylic acid (SA), as an intracellular and extracellular regulator of the plant response, is known as one of these effective compounds. Damask rose (Rosa damascena Mill.) is a medicinal plant from the Rosaceae, and its essential oils and aromatic compounds are used widely in the cosmetic and food industries in the world. Therefore, considering the importance of this plant from both medicinal and ornamental aspects, for the first time, we investigated one of the native cultivars of Iran (Kashan). Since one of the most important problems in Damask rose cultivation is the occurrence of salinity stress, for the first time, we investigated the interaction of several levels of NaCl salinity (0, 4, 8, and 12 ds m.sup.- 1) with SA (0, 0.5, 1, and 2 mM) as a stress reducer. Since salinity stress reduces plant growth and yield, in this experiment, the results showed that the increase in NaCl concentration caused a gradual decrease in photosynthetic and morphological parameters and an increase in ion leakage. Also, increasing the level of salinity stress up to 12 ds m.sup.- 1 affected the amount of chlorophyll, root length and leaf total area, all of which reduced significantly compared to plants under no stress. However, many studies have highlighted the application of compounds that reduce the negative effects of stress and increase plant resistance and tolerance against stresses. In this study, the application of SA even at low concentration (0.5 mM) could neutralize the negative effects of salinity stress in the Rosa damascena. In this regard, the results showed that salinity increases the activity of antioxidant enzymes catalase (CAT) and superoxide dismutase (SOD) and the concentration of proline, protein and glycine betaine (GB). Overexpression of antioxidant genes (Ascorbate Peroxidase (APX), CAT, Peroxidase (POD), Fe-SOD and Cu-SOD) showed an important role in salt tolerance in Damascus rose. In addition, 0.5 mm SA increased the activity of enzymatic and non-enzymatic systems and increased salinity tolerance. The change in weather conditions due to global warming and increased dryness contributes to the salinization of the earth's surface soils. Therefore, it is of particular importance to measure the threshold of tolerance of roses to salinity stress and the effect of stress-reducing substances in plants. In this context, SA has various roles such as increasing the content of pigments, preventing ethylene biosynthesis, increasing growth, and activating genes involved in stress, which modifies the negative effects of salinity stress. Also, according to the results of this research, even in the concentration of low values, positive results can be obtained from SA, so it can be recommended as a relatively cheap and available material to improve production in saline lands.
Soil salinization has rapidly encroached from the coastline to inland areas over the past two decades in the Yellow River Delta (YRD). Soil samples were collected from low‐ (LSW), medium‐ (MSW), and ...high‐ (HSW) salinity wetlands at a depth of 0–20 cm for 16S rRNA sequencing and bioinformatic analyses. The richness and α‐diversity indices were significantly lower in saline soils (ECe > 15 dS/m, HSW) than in soils those were not saline (ECe < 15 dS/m, LSW and MSW) (p < 0.05), generally showing a decreasing trend with increasing salinities. The phyla, Proteobacteria, Bacteroidetes, Chloroflexi, Acidobacteria and Planctomycetes, represented more than 70% of the bacterial community in the three wetlands, indicating the wide adaption of these phyla to salinity changes. Specifically, Proteobacteria was recognized as the most dominant (35.30% ‐ 38.59%) phylum regardless of salinity. Furthermore, bacterial composition was different among the wetlands, as revealed by β‐diversity indices and analysis of similarities. Linear discriminant analysis (LDA) effect size revealed the presence of 11, 2, and 10 discriminating bacterial taxa (LDA > 4) among LSW, MSW, and HSW, respectively, implying that they can serve as bioindicators of soil salinization. Redundancy analysis, Spearman correlation analysis, and the Mantel test suggested that salinity parameters (EC, Na+, K+, Mg2+, Ca2+, Cl−, and SO42−) prominently structured the bacterial community in the current study. These results suggest that the changes of bacterial composition would be induced in these LSW and MSW soils once seawater intrusion occurs.
Abstract
Soil salinity affects various crop cultivation but legumes are the most sensitive to salinity. Osmotic stress is the first stage of salinity stress caused by excess salts in the soil on ...plants which adversely affects the growth instantly. The Trehalose-6-phosphate synthase (
TPS
) genes play a key role in the regulation of abiotic stresses resistance from the high expression of different isoform. Selected genotypes were evaluated to estimate for salt tolerance as well as genetic variability at morphological and molecular level. Allelic variations were identified in some of the selected genotypes for the
TPS
gene. A comprehensive analysis of the
TP
S gene from selected genotypes was conducted. Presence of significant genetic variability among the genotypes was found for salinity tolerance. This is the first report of allelic variation of
TPS
gene from chickpea and results indicates that the SNPs present in these conserved regions may contribute largely to functional distinction. The nucleotide sequence analysis suggests that the
TPS
gene sequences were found to be conserved among the genotypes. Some selected genotypes were evaluated to estimate for salt tolerance as well as for comparative analysis of physiological, molecular and allelic variability for salt responsive gene Trehalose-6-Phosphate Synthase through sequence similarity. Allelic variations were identified in some selected genotypes for the
TPS
gene. It is found that Pusa362, Pusa1103, and IG5856 are the most salt-tolerant lines and the results indicates that the identified genotypes can be used as a reliable donor for the chickpea improvement programs for salinity tolerance.
Abstract
We expanded the batch-to-batch offsets of The International Association for the Physical Sciences of the Oceans (IAPSO) Standard Seawater (SSW) batches P145–P163 by intercomparison ...measurements using salinometers. On the basis of our results, we recommend using the correction factors instead of the offsets to correct the batch-to-batch differences, especially for salinity data outside the range of 30–40 g kg
−1
. We evaluated the expanded batch-to-batch correction factors by applying them to time series salinity data collected in the northwestern North Pacific Ocean and found that they are effective for detecting recent freshening (−0.6 ± 0.1 × 10
−3
g kg
−1
decade
−1
) in the deep North Pacific, which might be related to a reduction of the formation rate of Antarctic Bottom Water. We also evaluated the SSW linearity pack by applying the batch-to-batch correction factors. Linearity errors of the salinometers estimated from decade resistance substituters were consistent with the results of the linearity pack measurements. To correct the linearity errors of a salinometer, it might be suitable to use the more detailed distribution of those estimated from the decade resistance substituter than the linearity pack measurements. Since the cause of large batch-to-batch differences is still unclear, a reference seawater that is more robust and stable than SSW might be necessary to establish a high-level of international comparability of salinity measurements; the Multiparametric Standard Seawater (MSSW) currently under development might be a candidate for such reference seawater, because MSSW is expected to be more stable than SSW not only in practical salinity but also in absolute salinity.
Abstract
Marine heatwaves (MHWs) and low sea surface salinity (SSS) events can significantly impact marine ecosystems and dynamic systems, respectively. Compound marine extreme events can cause more ...significant damage than individual extreme events. However, the spatiotemporal patterns of compound MHW-low SSS extremes are not well understood. Daily reanalysis data were used to identify the basic patterns of compound extreme events and their drivers. These events mainly occur over the central tropical Pacific Ocean during record-breaking El Niño events. This analysis revealed that extreme sea surface warming associated with El Niño drives increased convection, which subsequently leads to increased rainfall. It ultimately causes extreme sea surface freshening. This analysis highlights the significance of air-sea interactions and low-frequency climate variability in shaping compound extreme events.
The Shapour River, with a catchment area of 4254 km
2
, is a major river system in southern Iran. While the upstream river flow (the upper Shapour River) is fresh, it becomes extremely salinized at ...the downstream confluence of the Shekastian saline tributary and the entering nearby Boushigan saline spring. Then, the river passes via the Khesht plain and finally discharges into Raeisali-Delvari storage dam which went into operation in 2009. Over the 2006–2019 period, reduced precipitation and over-utilization of freshwater resources resulted in ~ 72% streamflow reduction in the Shapour River. Due to not using the saline waters for irrigation, drinking, and industrial purposes, the ratio of saline-outflow of Shekastian tributary and Boushigan spring to fresh-outflow of upper Shapour River increased by ~ 3 times; consequently, river salinity fluctuation domain at the Khesht plain inlet dramatically increased from 2.1–4.0 dS m
−1
to 3.7–26.0 dS m
−1
. It resulted in major economic damages to the agricultural sector of middle Shapour River. On the seasonal timescale, consecutive processes of salt accumulation during irrigation season of the Khesht plain date orchards and then salt drainage during the rainy season have adjusted salinity fluctuation domain from 3.7–26.0 dS m
−1
at the plain inlet to 5.2–8.9 dS m
−1
at the plain outlet. In the lower Shapour River, storage/mixing of fresh/saline inflow waters in the Raeisali-Delvari reservoir has adjusted strong river salinity fluctuation domain from 0.9–10.7 dS m
−1
at the reservoir inlet to 3.6–5.5 dS m
−1
at the reservoir outlet. The success of the Raeisali-Delvari reservoir for salinity adjustment is due to its suitable location on the Shapour River, by being situated downstream of all main river tributaries with natural saline/fresh sources of water.
Plants are exposed to a range of biotic and abiotic stresses, including fungal infections and soil salinity. These stresses have negative impacts on plant growth and productivity, resulting in ...reduced yields and economic losses. To mitigate these effects, researchers have explored the use of biocontrol agents, such as
Trichoderma
, which can enhance plant growth and protect plants against various stresses. Salicylic acid (SA) is a key signaling molecule in plant defense against pathogens and plays a crucial role in activating the plant defense response. SA signaling pathways are known to be involved in the regulation of pathogenesis-related (PR) proteins, reactive oxygen species (ROS) production, and the synthesis of phytohormones, such as jasmonic acid (JA) and ethylene (ET). In this review, we evaluated the effect of
Trichoderma
treatment on SA signaling pathways and molecular markers in plants under salinity and
Fusarium
stresses. The findings showed that
Trichoderma
-treated plants exhibited enhanced SA signaling, as evidenced by the upregulation of SA-related genes. This was associated with improved disease resistance, as
Trichoderma
-treated plants showed lower disease severity and increased survival rates when exposed to
Fusarium
infection. Moreover,
Trichoderma
-treated plants also exhibited increased tolerance to salinity stress, as evidenced by improved physiological parameters, such as chlorophyll content and root growth. Molecular markers such as PR proteins and ROS-scavenging enzymes were upregulated in
Trichoderma
-treated plants, further indicating the activation of plant defense mechanisms. Overall, these findings suggest that
Trichoderma
-induced SA signaling and molecular markers contribute to the enhanced stress tolerance in plants, highlighting the potential of
Trichoderma
as a biocontrol agent for sustainable agriculture. Further studies are needed to elucidate the mechanisms underlying these effects and to optimize the use of
Trichoderma
in crop production.
The ocean carbon store plays a vital role in setting the carbon response to emissions and variability in the carbon cycle. However, due to the ocean's strong regional and temporal variability, sparse ...carbon observations limit our understanding of historical carbon changes.
Ocean temperature and salinity profiles are more widespread and rapidly expanding due to autonomous programmes, and so we explore how temperature and salinity profiles can provide information to reconstruct ocean carbon inventories with ensemble optimal interpolation. Here, ensemble optimal interpolation is used to reconstruct ocean carbon using synthetic Argo temperature and salinity observations, with examples for both the top 100 m and top 2000 m carbon inventories.
When considering reconstructions of the top 100 m carbon inventory, coherent relationships between upper-ocean carbon, temperature, salinity, and atmospheric CO2 result in optimal solutions that reflect the controls of undersaturation, solubility, and alkalinity.
Out-of-sample reconstructions of the top 100 m show that, in most regions, the trend in ocean carbon and over 60 % of detrended variability can be reconstructed using local temperature and salinity measurements, with only small changes when considering synthetic profiles consistent with irregular Argo sampling.
Extending the method to reconstruct the upper 2000 m reveals that model uncertainties at depth limit the reconstruction skill.
The impact of these uncertainties on reconstructing the carbon inventory over the upper 2000 m is small, and full reconstructions with historical Argo locations show that the method can reconstruct regional inter-annual and decadal variability.
Hence, optimal interpolation based on model relationships combined with hydrographic measurements can provide valuable information about global ocean carbon inventory changes.
PDF
