Water Salinization Research Articles

Eutrophication exacerbated organic pollution in lakes across China during the 1980s-2010s

Lakes are vital sources of drinking water and essential habitats for humans and various other living organisms. However, many lakes face organic pollution due to anthropogenic disturbance and climatic influence, and the spatiotemporal changes of organic pollution in lakes over a large area are still unclear. Based on three monitoring datasets of chemical oxygen demand (COD) in 390 lakes, this study demonstrated the apparent spatiotemporal differences of organic pollution in lakes during the 1980s-2010s and the effects of water eutrophication and salinization. Throughout China, lake organic pollution showed a general spatial trend of being more severe in the north compared to the south. This pattern is reflected in the positive linear correlations between in-situ COD concentrations and lake latitude, observed in both the 1980s (p < 0.05) and the 2010s (p < 0.01). In terms of spatial differences, the influence of total nitrogen concentrations increased from 0.27% in the 1980s to 35.24% in the 2010s. Moreover, with increasing human activity, 78.31% of the studied lakes (N = 83) showed increasing COD concentrations during the 1980s-2010s. In addition, the logarithmic dissolved organic carbon concentrations were linearly correlated with log water conductivities (Pearson's r = 0.49, p < 0.01), suggesting that lake expansion would attenuate organic pollution in saline lakes through dilution effects. These results are valuable for understanding the spatiotemporal dynamics of organic pollution and are crucial for effective management of organic pollution in different lakes.

Growth performance, blood health, and antioxidant status of freshwater carp under brackish water rearing system: Sustainable aquaculture approach in arid and semi-arid conditions

Global warming, water salinization, and increased anthropogenic usage of freshwater sources have had severe effects on water sources and aquaculture practices, which is consequently putting pressure on aquatic fauna and fish production. Hence, brackish water can be used as an alternative and sustainable approach to meet the increasing food requirements. Four groups with triplicates were designed to evaluate the impact of brackish water on Cirrhinus mrigala (n = 100) for 180 days; T0: control group (freshwater), T1: (5.45 ppt salinity), T2: (8.45 ppt salinity) and T3 (12.45 ppt salinity). Little behavioural alterations and normal feeding were observed in all experimental groups as compared to control group, except group T3. Survival rate was 100 % in all groups excluding group T3, which had shown 88 % survival rate (P < 0.05), while mean weight gain and length gain were observed better with low FCR in T1 and T2 groups (P < 0.05) but best growth rate observed at 5 ppt salinity level. Significant reduction in haemoglobin (Hb), hematocrit (HCT), red blood cells (RBCs) and increase in white blood cells (WBCs) and platelets (PLTs) was observed in group T3 compared to other experimental groups (P < 0.05). ALT, AST, ALP, urea, creatinine, and triglycerides, exhibited significant changes in T3 group after 180 days (P < 0.05). Erythrocytes had shown morphological alterations as; micronuclei, notching, blebbing, pear-shaped nuclei and spherocytes in T3 group. Significant increase in DNA damage in various tissues had indicated potential genotoxic impact of highly saline brackish water. Oxidative stress markers were increased significantly and antioxidants reduced (P < 0.05) at high salinity level brackish water (T3) until 180 days. In conclusion, C. mrigala can potentially grow well in brackish water system at 5 ppt salinity whereas, rise in salinity level (12 ppt) is detrimental to freshwater fish health and growth.

Present Understanding of Biodiversity of Anoxygenic Phototrophic Bacteria in the Relic Lake Mogilnoe (Kildin Island, Murmansk oblast, Russia)

The relic Lake Mogilnoe, separated from the Barents Sea by a sand and pebble dam, is located in the high Arctic on the Kildin island (Murmansk region). This lake is a classic example of a meromictic basin of marine origin. The data obtained during the 2018 expedition showed changes in the hydrochemical regime of the lake that have occurred over the past 20 years. Sulfide concentration in the monimolimnion of the lake was as high as 140 mg/L. A tendency for salinization of the surface waters to 7 g/L has been noted. The Lake Mogilnoe is characterized by a discrepancy between the halocline and thermocline levels. The chemocline zone in the lake is below the halocline level. In a narrow oxygen-containing layer between 3 and 7.5 m, aerobic microflora of the marine type and marine fauna were present. The bacterial plate was formed at the boundary of the sulfide layer at ~8 m and mainly consisted of green sulfur bacteria (GSB). Brown-colored GSB species containing bacteriochlorophyll e were predominant. The previously formed concept of anaerobic phototrophic bacteria (APB) biodiversity based on morphological characteristics was modified using metagenomic data obtained by analyzing DNA from two samples of lake water in the chemocline zone, and was also supplemented by identifying new GSB species. Molecular diagnostic data confirmed the absolute dominance of the brackish species of GSB Chlorobium phaeovibrioides. This is the first on isolation and identification of brown- and green-colored Prosthecochloris aestuarii morphotypes from Lake Mogilnoe and identified, as well as of bacteriochlorophyll c-containing Prosthecochloris sp. The taxonomic position of Pelodyction phaem, which was constantly present in the Lake Mogilnoe, is discussed in detail. Despite the partial isolation of the ecosystem of Lake Mogilnoe from the Barents Sea, the main properties of the dominant GSB species of GSB and Prosthecochloris aestuarii turned out to be similar to those of the phylotypes living in lakes on the White Sea coast of the, which remained connected with the Barents Sea.

Effects of grid resolution on regional modelled groundwater salinity and salt fluxes to surface water

Coastal fresh groundwaters face growing threats from rising withdrawals and climate change, with salinization of surface and groundwater as notable impacts. Recent developments in parallel variable-density modelling enable studying these threats at unexplored resolutions and extents. To improve the understanding of ground- and surface water salinization processes, we designed an experiment to measure how spatial resolution affects both groundwater salinity distribution and salt loads to surface waters. An existing parallelized coupled variable-density groundwater flow and salt transport (VD-GWT) model is applied to a region in the Netherlands whereby the surface water drainage network is parameterized at grid resolutions between 10 and 250 m. The results show a strong dependency between resolution and the salinity distribution in shallow groundwater while simulated salt loads are affected by imperfect flux scaling. The computational resources needed for this test suggest that regional high-resolution VD-GWT models are feasible using HPC environments, albeit not practical.

INSULARITY, ENVIRONMENTAL VULNERABILITIES AND ADAPTATION STRATEGIES IN THE BLISS KASSA ISLANDS IN CASAMANCE (SENEGAL)

The relationship between the environment and societies is a complex one in terms of the way in which human communities interact with the environment. This relationship is characteristic of the different uses made of the areas in which they live. A segmented approach is therefore needed to understand how these areas are changing, hence the choice in this research to focus on small island areas in the Ziguinchor region of southern Senegal. The article looks at three main challenges identified in this area, including waste production and management, sea encroachment and salinisation. A qualitative approach was adopted in order to gather peoples perceptions and experiences of spatial change over time in relation to natural and anthropogenic dynamics, the consequences of these changes and related adaptation strategies. The results of the semi-structured interviews and focus groups show: firstly, a change in lifestyles and an excessive accumulation of plastic waste that popular recycling practices are unable to contain secondly, a loss of freshwater resources with the accelerated salinisation of groundwater and surface water thirdly, a decline in socio-economic living spaces with the advance of the sea, which also contributes to salinisation. The findings show that the people of Bliss Kassa are increasingly vulnerable, while the public systems in place to deal with these issues remain embryonic and largely outstripped by the pace of change.

Field evaluation and characterization of a novel biostimulant for broccoli (Brassica oleracea var. italica) cultivation under drought and salt stress which increases antioxidant, glucosinolate and phytohormone content

Anthropogenic global warming is affecting crop yield and thus compromising food security. Drought and salinization of the irrigation water or soil are increasingly frequent in most arable land, specifically in arid and semiarid areas such as the Mediterranean basin. Many crops have been displaced or their yield has plummeted in recent years, causing food shortages and price increases. In a context of global population growth and reduction in the availability of natural resources used in agriculture, finding novel tools that help farmers to maintain yield in an increasingly arid and saline scenario is of pivotal importance. This is particularly important in organic agriculture, where the number of available tools is very limited. Biostimulants are substances or microorganisms of natural origin whose function is to stimulate plant processes related to nutrient absorption, nutrient use efficiency, tolerance to abiotic stress or the quality of the agricultural products obtained. In the present work, we have evaluated, in field, the agronomic effectiveness of a novel biostimulant formulation in a cruciferous crop of great interest in the Mediterranean basin (broccoli) under control conditions, water and salt stress. Our research has shown that our product had a positive effect on broccoli production and in delaying flowering time. We have also found that the application of our biostimulant increased enzymatic and non-enzymatic antioxidant defense under drought conditions. Similarly, when exposed to salinity, the biostimulant increased the concentration of different phytohormones and glucosinolates. Taken together, our biostimulant increases the tolerance of broccoli to salt stress and water limitation by increasing the antioxidant response, the level of glucosinolates and eliciting the hormonal response.

Dissolved and particulate metals and metalloids in the eastern Mekong Delta, Vietnam

The article reports the concentration levels of particulate and dissolved metals and metalloids (Be, Se, Sb, Tl, V, Pb, Cd, Cu, Zn, Ni, Mo, Co, Fe As, Ag) in the eastern region of the lower Mekong Delta (Vietnam) in order to assess their possible influence on the environmental quality of river water. To measure the concentrations of trace elements, a mass spectrometric method was used. The critical particulate elements had included V, Cu, Ni, Co, Pb, Cd and potentially critical – Mo, Ag, Se, Tl. In the dissolved phase these were Cu, Zn, and Pb, Cd, Co, Ag, Se respectively. The high accumulation ability of studied elements to suspended particulate matter (102–107) suggests their important role in the distribution of elements. The water salinization boundary in the riverbeds of the delta moves upstream 30–50 km further in the dry season compared to the wet season.

Integrated geophysical exploration, water quality mapping and salinization of the coastal aquifers in Bonaberi, Douala, Cameroon

Integrated geophysical exploration, water quality mapping and salinization of the coastal aquifers in Bonaberi, Douala, Cameroon

Enhancing hydrological insight: isotopic methods revealing groundwater–surface water interactions in the Lower Quang Tri River Group, Vietnam

ABSTRACT The Lower Quang Tri River Group, situated in central Vietnam, faces a myriad of challenges, notably the decline in groundwater levels and the salinisation of both groundwater and surface water, significantly impacting water availability for domestic, agricultural, and industrial purposes. To address these pressing concerns, this study adopts a comprehensive methodology integrating hydrogeological measurements, isotopic techniques, and chemical analyses of various water sources, including local precipitation, surface water bodies, reservoirs, and groundwater samples. Utilising the deuterium and oxygen-18 signatures (δ 2H and δ 18O) in water molecules as environmental tracers for the assessment of base flow and water sources enables a nuanced understanding of the intricate interaction between surface water and groundwater. Research findings elucidate that during the dry season, groundwater recharge primarily stems from water in the reservoirs over approximately seven months. Base flow contributes between 80 and 85 % of streamflow during the rainy season, escalating to 100 % during the dry season. The mean travelling time of the base flow is estimated at 120 ± 10 days using the sine curve model developed by Rodgers et al. The insights gleaned from this study are poised to play a pivotal role in guiding the local water resources managers in licensing for the exploitation of a right quantities of groundwater as sustainable management strategies in the region.

Stimulatory Effect of an Extract of Lemna minor L. in Protecting Maize from Salinity: A Multifaceted Biostimulant for Modulating Physiology, Redox Balance, and Nutrient Uptake

Water and soil salinization significantly reduce crop yields. Among the strategies developed to counteract salt stress, biostimulants can maintain crop productivity, reversing its impact. In this context, there is interest in finding new substances that could act as biostimulants. Recently, the biostimulatory potential of Lemna minor L. (duckweed) extracts has been shown. This work aimed to highlight whether an extract from duckweed (Lemna extract—LE) could protect maize grown in salinity, exploring the mechanisms induced to improve crop resistance. Plants were grown by applying two concentrations of NaCl (150 and 300 mM), and some physiological, morphological, and biochemical traits were studied in control and salt-stressed samples, treated or not with LE. Salinity decreased shoots, roots, pigment, and soluble protein. LE prompted ameliorative changes at the root level and increased photosynthetic pigment and soluble protein. Furthermore, concerning the oxidative impairment provoked by salt stress, LE enhanced the cellular redox state, contrasting H2O2 and MDA accumulation and positively affecting the activity of superoxide dismutase (SOD—EC 1.15.1.1) and catalase (CAT—EC 1.11.1.6). The assessment of some mineral nutrients showed that LE stimulated their acquisition, especially for the highest salt dosage, explaining some benefits found for the parameters investigated.

Application of Geochemical and Isotopic Tools to Investigate Water Recharge and Salinization in a Coastal Phreatic Aquifer Suffering Severe Natural and Anthropogenic Constraints: Case of the Mornag Aquifer, NE Tunisia

Application of Geochemical and Isotopic Tools to Investigate Water Recharge and Salinization in a Coastal Phreatic Aquifer Suffering Severe Natural and Anthropogenic Constraints: Case of the Mornag Aquifer, NE Tunisia

Source analysis of chlorine in municipal solid waste under waste classification: a case study of Hangzhou, China.

Inorganic chlorine is susceptible to water and soil salinization due to its non-degradability and high mobility. To clarify the environmental risks associated with the active inorganic chlorine in municipal solid waste (MSW), the specific characteristics and contributions of inorganic chlorine in different MSW categories were investigated in this study. MSW samples were collected from eight representative waste classification residential areas in Hangzhou, China. It was found that the inorganic chlorine content in different MSW categories varied significantly (0-113 mg/g). Perishable waste, paper, and plastic were found to be the main sources of inorganic chlorine in MSW. A four-category classification system was used to quantify the contribution of inorganic chlorine from each waste category. It was found that the misclassification of inorganic chlorine contributions from perishable waste and other waste accounted for 51.96% and 48.04%, respectively. However, when correctly classified into the four-category system, their contributions were reduced to 67.14% and 30.65%, respectively. Therefore, MSW classification showed a significant reduction in the overall contribution of inorganic chlorine. The misclassification reduces the contribution of inorganic chlorine to 48.04%, while correct classification increases the reduction to 69.35%.

Effects of water salinization and substrata quality on the performance of the shredder Schizopelex festiva (Trichoptera; Sericostomatidae)

Secondary salinization is a growing concern for freshwaters worldwide. The lethal and sub-lethal effects on shredders are known, but not whether these result from direct exposure to contaminated aquatic medium and/or from indirect effects of distinct substrate quality through fungal conditioning in salinized media. Here, chestnut and oak leaves were conditioned for 4 weeks in reference (Cond0, 0 g/l NaCl) or salinized (Cond3, 3 g/l NaCl) media before being offered to the shredder Schizopelex festiva maintained in reference (Inv0) or salinized (Inv3) media. Fungal biomasses associated with leaf litter and consumption, respiration rates, growth, survival, and feeding preference of S. festiva were assessed. We found lower fungal biomass in both leaf species conditioned in Cond3 medium. Consumption rates were higher for oak than chestnut, and in Inv0 than Inv3, but were not affected by conditioning media. Growth was also affected by invertebrate media (Inv0 > Inv3), while Inv3 led to the lowest survival. Schizopelex festiva preferred Cond0 over Cond3 oak leaves only in Inv0. Results strongly suggest that direct exposure to salinized media is a main pathway of salt toxicity to shredders through a generalized reduction in invertebrates’ metabolic rates when facing salt stress. Salt addition to the media may result in an energetic investment in osmotic regulation at the expense of consumption and growth, with consequences for invertebrate survival. Potential negative effects of salt contamination on shredders’ ability to select more nutritious food items may contribute to cascading effects throughout the stream food webs, particularly in streams lined with more recalcitrant leaf litter.

Grafting in Capsicum peppers as a strategy to mitigate the effects of climate change on yield and quality factors

Climate change in the Mediterranean areas is increasing problems on droughts, water availability and salinization of irrigation water. These are probably some of the most limiting factors on farming, especially in vegetables production. Capsicum peppers, one the most valuable vegetables in Spain, are quite sensitive to water deficit and particularly to salinity. The use of rootstocks tolerant to these abiotic stresses could be explored as a short/mid-term solution. In this work, we evaluated the ability as rootstocks of several accessions, together commercial F1 ‘Robusto’ and ‘Oscos’, with the cultivar ‘Herminio’ as scion, under control, drought (30% decrease irrigation) and salinity (5.8 dS m-1) in Campo de Cartagena area (Murcia, Spain). Yield and fruit weight, and water content, ascorbic acid content (AAC) and total phenolics (TP) at the unripe and fully ripe commercial stages were evaluated. Under control conditions, our rootstocks did not provide extra vigour and yield as none showed higher performance than the non-grafted ‘Herminio’ in yield (10 kg m-2) and fruit weight (215 g). However, drought and salinity conditions revealed that some accessions might be useful as rootstocks, providing higher yields and/or fruit size than ‘Herminio’, particularly yield under drought, i.e. 5-7 kg m-2 while ‘Herminio’ only achieved 4 kg m-2, and fruit weight in both stress conditions (i.e. 190-223 g vs 173 g under drought, 187-209 g vs 158 g under salinity). On average, drought increased the levels of antioxidants at both ripening stages, while salinity decreased them, specially AAC. Also, remarkable rootstock × treatment interactions, particularly in phenolics, enabled identifying several rootstocks providing high levels of antioxidants at both ripening stages and under both abiotic stresses, improving those from non-grafted ‘Herminio’.

Recent Advances in the Crosstalk between Brassinosteroids and Environmental Stimuli.

Due to their sessile lifestyle, plants need to optimize their growth in order to adapt to ever-changing environments. Plants receive stimuli from the environment and convert them into cellular responses. Brassinosteroids (BRs), as growth-promoting steroid hormones, play a significant role in the tradeoff between growth and environmental responses. Here, we provide a comprehensive summary for understanding the crosstalk between BR and various environmental stresses, including water availability, temperature fluctuations, salinization, nutrient deficiencies and diseases. We also highlight the bottlenecks that need to be addressed in future studies. Ultimately, we suppose to improve plant environmental adaptability and crop yield by excavating natural BR mutants or modifying BR signaling and its targets.

Soil salinity and salt tolerance of plants

Global scarcity of water resources, ecological pollution and enlarged salinization of soil and water became a noticeable problem at the beginning of the 21st century. Soil pollution caused by industrial and agricultural activities is an environmental problem that poses serious threats to human health and ecosystems. This review provides, firstly soil salinity characteristics and salinity indicators. Secondly, we focused on saline areas in the world and causes of soil salinization. Thirdly, mapping and monitoring of soil salinity areas and improvement measures for saline soil tolerance. Fourthly, effect of salinity stress on plant and plant salinity response was discussed. This review is intended to provide a comprehensive overview on salinization of soil and presenting fundamental information for future research studies.

Salinisation of drinking water ponds and groundwater in coastal Bangladesh linked to tropical cyclones

Salinity is a widespread problem along the Asian coast, mainly in reclaimed lands where most people live. These low-lying areas are vulnerable to impacts from tropical cyclone induced storm surges. The role of such surges on the long-term salinity of water resources, particularly the salinisation of drinking water ponds, a key water resource, requires further investigation. Here we show, using high-resolution measurements of pond hydrology and numerical modelling, that episodic inundation events cause the widespread salinisation of surface water and groundwater bodies in coastal areas. Sudden salt fluxes in ponds cause salinity build-up in the underlying sediments and become a source of salinity. Rapid clean-up of drinking ponds immediately after a surge event can significantly minimize these salinity impacts, which are likely to increase under climate change. Our study has implications for coastal land use and water resources management in tropical deltas.

Planning for Drinking Water Salinization in the U.S. Atlantic and Gulf Coast Regions

Problem, research strategy, and findings Sea-level rise will bring ocean salts inland and salinize the drinking water sources of some coastal communities. How are municipalities, regions, and states preparing for salinization? In this study I evaluated 264 climate plans and seven state water plans from the Atlantic and Gulf coasts of the United States. Of these, 65 climate adaptation plans engaged with salinization in the context of drinking water; 21 made salinity adaptation recommendations, 6 discussed implemented monitoring or modeling, and 11 discussed implemented adaptation strategies. In state water plans, some states showed considerable salinization adaptation activity, but not all linked these actions to climate adaptation. Despite seawater intrusion and salinization being widely recognized, actions were concentrated in fewer states. Maryland, Delaware, Virginia, Florida, and Texas exhibited high degrees of engagement. Louisiana, Mississippi, Alabama, and Georgia showed little evidence of planning for salinization in climate or state water plans. In the absence of federal or state governments leading on managing sea-level rise–driven salinization, evaluating and preparing for the challenge of salinization is likely to become the de facto responsibility of coastal water suppliers and well owners, who may not have the capacity, budget, or jurisdiction to adequately monitor and protect supplies. Takeaway for practice Left to individual drinking water suppliers and well owners with varying capacity for adaptation, water supply salinization driven by sea-level rise has the potential to exacerbate existing inequities in drinking water provision. Planners can contribute to adapting coastal drinking water systems by integrating monitoring and modeling into climate adaptation plans, creating partnerships that enable drinking water adaptation actions, and supporting new approaches to water funding and financing.

Projected climate oligotrophication of the Adriatic marine ecosystems

The Adriatic Sea hosts diverse marine ecosystems, characterized by rich biodiversity and unique ecological dynamics. Its intricate coastal habitats and open waters support a range of species and contribute to the region's ecological and economic significance. Unraveling the consequences of the ongoing climate changes on this delicate environment is essential to ensure the future safeguard of this basin. To tackle this problem, we developed a biogeochemical model for the entire basin, with a horizontal resolution of about 2 km and 120 vertical levels, forced by the projections of atmosphere, hydrology and ocean circulation between 1992 and 2050, under emission scenario RCP8.5. The changes projected between 2031–2050 and 1992–2011 were evaluated on ecoregions characterized by different trophic conditions, identified using a k-medoid classification technique. The results point toward a generalized oligotrophication of the basin, especially intense in the northern estuarine areas, driven by a substantial decrease in river discharge projected for the rivers of the Po Plain. This scenario of unproductive and declining resources, together with the ongoing warming, salinization, and acidification of marine waters, cast doubt on the long-term resilience of the Northern Adriatic food web structure, which has evolved to thrive in high trophic conditions. The outcome of this study provides the stakeholders with a tool to understand how potential long-term decreases in the regimes of the Northern Adriatic Rivers could affect the marine ecosystem and its goods and services in the future.

Faith in Science: Religion and Climate Change Attitudes in the Middle East

Abstract The Middle East is facing many challenges because of climate change: extreme heat, recurring droughts, water salinization, and more. Yet little is known about how people in the region perceive the threat of climate change or about the factors associated with perceiving it as more or less of a threat. This study utilizes the Arab Barometer surveys and examines how religion influences climate change perceptions among 13,700 people across twelve countries. Contrary to arguments in the literature, Muslims tend to be less concerned about climate change compared to Christians. Yet all Middle Easterners with a strong sense of religiosity are more concerned about climate change relative to their counterparts. Political attitudes also matter. Religious Muslims who endorse Islamist government are less concerned than secular Muslims, suggesting a “culture war” on the issue. These findings show that religion exerts a nuanced and unexpected influence on how people evaluate the climate change crisis.