Low Salinity Conditions Research Articles

Water quality, shrimp growth performance and bacterial community in a reusing-water biofloc system for nursery of Penaeus vananmei rearing under a low salinity condition

This study aimed to investigate water quality, growth performance of Penaeus vananmei postlarvae (PL) and bacterial community in a reusing-water biofloc system under a low salinity condition. PLs (~ stage 15) were stocked in two biofloc systems: the reusing-water system (RS) and the new-water system (NS), at a density of 4000 individuals m−3 for a 28-days nursery experiment at a salinity of 5.0‰, with a C:N of 15:1. Results showed an acceptable growth performance of shrimp in RS that the final body weight and productivity were 0.104 ± 0.014 g shrimp−1 and 0.37 ± 0.05 kg m−3, although those parameters were significantly lower than those in NS (0.138 ± 0.018 g shrimp−1 and 0.48 ± 0.07 kg m−3, P < 0.05). However, the survival rate of shrimp in RS (88.9 ± 4.2%) was not significantly different from that of NS (86.6 ± 6.5%, P = 0.786). The TAN and nitrite levels in RS were 1.90 ± 0.42 and 6.55 ± 0.86 mg L−1, non-significantly higher than those in NS (0.04 ± 0.02 and 0.07 ± 0.01 mg L−1, P ≥ 0.05). Whereas, the levels of total nitrogen (285.5 ± 10.2 mg L−1) and nitrate (24.8 ± 2.7 mg L−1) in RS were significantly higher than those in NS (231.3 ± 6.1 and 4.6 ± 0.4 mg L−1, P < 0.05). The Shannon index of bacterial community in RS (6.22 ± 0.02) was significantly lower than that in NS (7.23 ± 0.02, P < 0.05). The bacterial communities in both systems were dominated by Bacteroidetes (10.64–15.55%), Firmicutes (4.11–9.42%), Planctomycetes (14.43–29.67%) and Proteobacteria (38.73–50.35%) with few ammonia- and nitrite-oxidizing bacteria. The proportions of denitrification bacteria and heterotrophic nitrification-aerobic denitrification bacteria in RS were 0.65 ± 0.07% and 5.73 ± 0.23%, significantly lower than those in NS (9.05 ± 0.15% and 9.26 ± 0.14%, P < 0.05). The results suggested that acceptable growth performance of postlarvae and water quality could be obtained in the reusing-water biofloc system, although the nitrogenous load was slightly high and should be studied next to reduce.

Characteristics of Shale Wettability by Contact Angle and Its Influencing Factors: A Case Study in Songliao

Wettability is a significant factor in the exploration and development of shale oil. Currently, shale wettability has yet to reach a unified understanding. The contact angle is widely used in the study of shale wettability. However, the pre-treatment of the shale profoundly affects the contact angle. In this paper, the contact angle errors introduced by the pre-treatment of samples are discussed. Shale wettability is influenced by many factors, and there is not yet a systematic study of its influencing factors. Based on the above issues, the shale of the northern Songliao Basin was taken as the subject. The wettability of the different lithofacies is characterized by an improved contact angle method. The compositional characteristics of the shales and oil in the study area were analyzed. Fresh minerals, a single component of oil, and different temperature/pressure conditions were set up to investigate the influencing factors of shale wettability. The studies show that Organic matter abundance and thermal maturity have a positive correlation with oil-wet. Siliceous minerals are positively correlated with water-wet. Carbonate and clay minerals are negatively correlated with water-wet. The mineralogical composition of the shale, the composition of the oil, the characteristics of the aqueous media, the asphaltene deposits on the surface, temperature, and pressure all impact wettability. The affinity of minerals for hydrocarbons is iron minerals &amp;gt; carbonate minerals &amp;gt; clay minerals &amp;gt; siliceous minerals. Minerals are more hydrophilic at low salinity conditions. The deposition of non-hydrocarbons and asphaltenes renders the surface oleophilic. Increasing temperatures will reduce the hydrophilicity of the “oil-water-rock”.

Impact of Drought and Changing Water Sources on Water Use and Soil Salinity of Almond and Pistachio Orchards: 2. Modeling

California is increasingly experiencing drought conditions that restrict irrigation deliveries to perennial nut crops such as almonds and pistachios. During drought, poorer quality groundwater is often used to maintain these crops, but this use often results in secondary salinization that requires skilled management. Process-based models can help improve management guidelines under these challenging circumstances. The main objective of this work was to assess seasonal soil salinity and root water uptake as a function of irrigation water salinity and annual rain amounts. The manuscript presents a comparison of three-year experimental and numerically simulated root zone salinities in and below the root zone of almond and pistachio drip-irrigated orchards at multiple locations in the San Joaquin Valley (SJV), California, with different meteorological characteristics. The HYDRUS-1D numerical model was calibrated and validated using field measurements of soil water contents and soil solute bulk electrical conductivities at four root zone depths and measured soil hydraulic conductivities. The remaining soil hydraulic parameters were estimated inversely. Observations and simulations showed that the effects of rain on root zone salinity were higher in fields with initially low salinities than in fields with high salinities. The maximum reduction in simulated root water uptake (7%) occurred in response to initially high soil salinity conditions and saline irrigation water. The minimum reduction in simulated water uptake (2.5%) occurred in response to initially low soil salinity conditions and a wet rain year. Simulated water uptake reductions and leaching fractions varied at early and late times of the growing season, depending on irrigation water salinity. Root water uptake reduction was highly correlated with the cumulative effects of using saline waters in prior years, more than salt leaching during a particular season, even when rain was sufficient to leach salts during a wet year.

Hemocyte Responses of the Oyster Crassostrea hongkongensis Exposed to Diel-Cycling Hypoxia and Salinity Change

Marine hypoxia caused by nutrient enrichment in coastal waters has become a global problem for decades, especially diel-cycling hypoxia that occurs frequently in the summer season. On the contrary, sudden rainstorms, and freshwater discharge make salinity in estuarine and coastal ecosystems variable, which often occurs with hypoxia. We found mass mortality of the Hong Kong oyster Crassostrea hongkongensis in the field where hypoxia and salinity fluctuation co-occur in the summer season during the past several years. To investigate the effects of diel-cycling hypoxia and salinity changes on the hemocyte immune function of C. hongkongensis, oysters were exposed to a combined effect of two dissolved oxygen (DO) concentrations (24 h normal oxygen 6 mg/L, 12 h normal oxygen 6 mg/L, and 12 h hypoxia 2 mg/L) and three salinities (10, 25, and 35‰) for 14 days. Subsequently, all treatments were restored to constant normal oxygen (6 mg/L) and salinity under 25‰ for 3 days to study the recovery of hemocyte immune function from the combined stress. Hemocyte parameters were analyzed by flow cytometry, including hemocyte mortality (HM), total hemocyte count (THC), phagocytosis (PHA), esterase (EST) activity, reactive oxygen species (ROS), lysosomal content (LYSO), and mitochondrial number (MN). The experimental results showed that diel-cycling hypoxia and salinity changes have obvious interactive effects on various immune parameters. In detail, diel-cycling hypoxia and decreases in salinity led to increased HM, and low salinity caused heavier impacts. In addition, low salinity, and diel-cycling hypoxia also led to decreases in LYSO, EST, and THC, while the decrease of PHA only occurs in the early stage. On the contrary, ROS production increased significantly under low salinity and hypoxic conditions. After 3-day recovery, THC, PHA, EST, LYSO, and MN were basically restored to normal, while HM and ROS were still significantly affected by diel-cycling hypoxia and salinity change, indicating that the combined stress of diel-cycling hypoxia and salinity changes had latent effects on the immune function of C. hongkongensis. Our results highlight that diel-cycling hypoxia and salinity change may impair the health and survival of the Hong Kong oyster C. hongkongensis and may be the key factors for the mass mortality of this oyster in the field.

Evolutionary Change in the Eastern Oyster, Crassostrea Virginica, Following Low Salinity Exposure.

The presence of standing genetic variation will play a role in determining a population's capacity to adapt to environmentally relevant stressors. In the Gulf of Mexico, extreme climatic events and anthropogenic changes to local hydrology will expose productive oyster breeding grounds to stressful low salinity conditions. We identified genetic variation for performance under low salinity (due to the combined effects of low salinity and genetic load) using a single-generation selection experiment on larvae from two populations of the eastern oyster, Crassostrea virginica. We used pool-sequencing to test for allele frequency differences at 152 salinity-associated genes for larval families pre- and post-low salinity exposure. Our results have implications for how evolutionary change occurs during early life history stages at environmentally relevant salinities. Consistent with observations of high genetic load observed in oysters, we demonstrate evidence for purging of deleterious alleles at the larval stage in C. virginica. In addition, we observe increases in allele frequencies at multiple loci, suggesting that natural selection for low salinity performance at the larval stage can act as a filter for genotypes found in adult populations.

The non-linear effect of oil polarity on the efficiency of low salinity waterflooding: A pore-level investigation

Oil polarity is an important property impacting the efficiency of low salinity waterflooding (LSWF). It directly affects fluid/fluid and rock/fluid interactions, controlling the interfacial properties and forces. However, the current findings in the literature on the effect of concentration of polar components on oil recovery by LSWF are contradictory. Therefore, the main objective of this paper is to investigate how the type of non-polar fractions and the concentration of acidic polar oil constituents change the trapped oil saturation at the pore-scale during LSWF. In this regard, we conducted a series of microfluidics LSWF experiments in both secondary and tertiary modes, using clay-free glass micromodels of representative elementary volume (REV) size. Both model oils and crude oil were tested. The polarity of model oils was manipulated by introducing different amounts of oleic acid into the samples. In addition, the contact angle under dynamic salinity alteration (CA-DSA), interfacial tension (IFT), and oil/brine zeta-potential were measured as a function of oil polarity for a detailed understanding of the pore-scale results.Based on the results, polar acidic fraction increases both the oil-wetting tendency under high salinity (HS) condition and the degree of wettability alteration under low salinity (LS) condition. Increasing the concentration of the polar components in the model oils resulted in reducing oil/brine IFT by 7–9 mN/m in HS and 8–12 mN/m in LS. As the IFT was reduced, the sweep efficiency of both HS and LS flooding was improved, which can be ascribed to the reduction of capillary trapping. However, the change of IFT by change of salinity was minor; thus, it cannot be considered a primary mechanism of LSWF. The ultimate oil recovery from HS and LS injection steps was highest when crude oil was used than using the most polar model oil. In the absence of polar components, no incremental oil recovery during LSWF was observed regardless of the molecular weight of the model oil. The efficiency of LSWF with all the polar oils was higher in the secondary injection than in the tertiary mode, as also reported in core-scale studies.The main novel insight from the study is that the oil recovery factor by LSWF is logarithmically correlated with the oil polarity. The measured zeta-potential at the oil/brine interface also confirms a logarithmic correlation between the oil/brine interface potential and the concentration of polar components in the oil samples. This highlights that the bulk concentration of polar groups and their respective concentration at the oil/brine interface are not linearly related. Therefore, the acid number alone cannot predict the concentration of polar components at the interface and is not recommended to be used for screening potent oils.

Impacts of low pH and low salinity induced by acid rain on the photosynthetic activity of green tidal alga Ulva prolifera

Acid rain is a serious environmental problem and has obvious impacts on the growth, reproduction, and photosynthesis of terrestrial plants. Ulva prolifera, a main blooming species of green tides, was studied on its physiological response to acid rain. The photosynthetic parameters were determined under different conditions (salinity: 1, 10, 30&permil;; pH: 3.0, 3.5, 4.5; duration: 0.5, 1.0, 2.0 h) followed by 24-h recovering under natural conditions. Results showed 1-h treatment with pH 3.5 caused 50-70% reduction in the maximal quantum yield of PSII photochemistry (Fv/Fm) and effective quantum yield of PSII photochemistry (&#x424;PSII) at normal salinity but when the low pH was combined with a salinity of 10&permil; or lower, PSII activity was almost completely inhibited. Moreover, the low salinity (1&permil; and 10&permil;) reduced the degree of photoprotection under low pH (3.5) conditions. Finally, we speculated if the pH of acid rain &le; 3.5, with 1&permil; salinity and 2-h rainfall time, the amount of U. prolifera and the scale of green tides would decrease.

Novel lncRNA lncRNA001074 participates in the low salinity-induced response in the sea cucumber Apostichopus japonicus by targeting the let-7/NKAα axis.

Salinity fluctuations have severe impacts on sea cucumbers and therefore important consequences in sea cucumber farming. The responses of sea cucumbers to salinity changes are reflected in the expression profiles of multiple genes and non-coding RNAs (ncRNAs). The microRNA (let-7) which is a developmental regulator, the ion transporter gene sodium potassium ATPase gene (NKAα), and the long ncRNA lncRNA001074 were previously shown to be involved in responses to salinity changes in various marine species. To better understand the relationship between ncRNAs and target genes, the let-7/NKAα/lncRNA001074 predicted interaction was investigated in this study using luciferase reporter assays and gene knockdowns in the sea cucumber Apostichopus japonicus. The results showed that NKAα was the target gene of let-7 and NKAα expression levels were inversely correlated with let-7 expression based on the luciferase reporter assays and western blots. The let-7 abundance was negatively regulated by lncRNA001074 and NKAα both in vitro and in vivo. Knockdown of lncRNA001074 led to let-7 overexpression. These results demonstrated that lncRNA001074 binds to the 3'-UTR binding site of let-7 in a regulatory manner. Furthermore, the expression profiles of let-7, NKAα, and lncRNA001074 were analyzed in sea cucumbers after the knockdown of each of these genes. The results found that lncRNA001074 competitively bound let-7 to suppress NKAα expression under low salinity conditions. The downregulation of let-7, in conjunction with the upregulation of lncRNA001074 and NKAα, may be essential for the response to low salinity change in sea cucumbers. Therefore, the dynamic balance of the lncRNA001074, NKAα, and let-7 network might be a potential response mechanism to salinity change in sea cucumbers.

Unraveling Salinity Extreme Events in Coastal Environments: A Winter Focus on the Bay of Brest

Extreme weather events affect coastal marine ecosystems. The increase in intensity and occurrence of such events drive modifications in coastal hydrology and hydrodynamics. Here, focusing on the winter period (from December to March), we investigated multi-decade (2000–2018) changes in the hydrological properties of the Bay of Brest (French Atlantic coast) as an example of the response of a semi-enclosed bay to extreme weather episodes and large-scale atmospheric circulation patterns. The relationships between extreme weather events and severe low salinity conditions (as a proxy for changes in water density) were investigated using high-frequencyin situobservations and high-resolution numerical simulations. The identification of intense episodes was based on the timing, duration, and annual occurrence of extreme events. By examining the interannual variability of extreme low salinity events, we detect a patent influence of local and regional weather conditions on atmospheric and oceanic circulation patterns, precipitation, and river runoff. We revealed that low salinity events in Brittany were controlled by large-scale forcings: they prevailed during the positive phase of the North Atlantic Oscillation and periods of low occurrences of the Atlantic Ridge weather regime. The increase in severe storms observed in western France since 2010 has led to a doubling of the occurrence and duration of extreme low salinity events in Brittany.

The Effects of Suspended Particulate Matter, Nutrient, and Salinity on the Growth of Amphidinium carterae Under Estuary Environmental Conditions

The environmental conditions in estuaries display distinct variability along the river-ocean mixing continuum from turbid, eutrophic freshwater to clear, oligotrophic offshore oceanic water. In order to understand the effects of suspended particulate matter (SPM), nutrient, and salinity on phytoplankton growth, this study investigated the response of a harmful dinoflagellate (Amphidinium carterae Hulburt) to the ecological gradients in estuary environments. Rapid nutrient uptake and growth of A. carterae were detected in the nutrient-rich clear water, while nutrient concentration had little impact on the cellular chlorophyll a (Chl-a) content at the stationary phase. Light attenuation caused by SPM not only inhibited the specific growth rate of A. carterae but also prolonged its adaption period in turbid water, resulting in a delayed and weakened growth response. The elevated cellular Chl-a content under high SPM conditions resulting from photo-acclimation led to the decoupling of cell density and Chl-a concentration, indicating that Chl-a is not a reliable indicator for phytoplankton abundance in turbid environments. The combined effect of SPM and nutrient on specific growth rate of A. carterae can be explained by the comparative effect model, while the multiplicative effect model better predicted their interactive effect on the growth inhibitory rate (GIR). There is a transit of dominant limiting factor for phytoplankton growth along the salinity gradient in estuary environments. Salinity (for marine phytoplankton cannot survive under low salinity condition) and SPM are the dominant limiting factors at low salinities in nearshore turbid environments, while nutrient depletion exerts the dominant inhibitory effect in high salinity offshore water. Depending on the balance between enhancing nutrient limitation and reducing light limitation with increasing salinity, blooms most likely occur in the “optimal growth region” at intermediate salinities where light and nutrient are both suitable for phytoplankton growth.

The Effects of Temperature and Salinity Stressors on the Survival, Condition and Valve Closure of the Manila Clam, Venerupis philippinarum in a Holding Facility

We investigated the response of the Manila clam Venerupis philippinarum to possible temperature and salinity changes in a holding facility. First, clams were exposed to four temperatures for 15 days. Valve closure and survival of clams exposed to seawater at 18 °C were higher than that of those exposed to seawater at 24 °C. Second, clams were exposed to six salinities for 15 days. Survival of clams exposed to two salinity fluctuation conditions (24–30 and 27–24 psu) was lower than that of clams exposed to constant 30 psu conditions. Valve closures of clams exposed to constant low salinity conditions (24 psu) and two salinity fluctuation conditions (24–30 and 27–24 psu) were higher than those exposed to constant 30 psu conditions. Lastly, clams were exposed to two different temperatures and three different salinity conditions for 8 days. Valve closure and survival decreased significantly under the combination of 24 °C and 18 psu. These results suggest that an increase in temperature or a wider range of salinity fluctuations are detrimental to the survival of the Manila clam. The synergistic effect of temperature and salinity stressors may decrease the survival period of clams compared to the effect of a single stressor.

Physiological Responses of the Submerged Macrophyte Stuckenia pectinata to High Salinity and Irradiance Stress to Assess Eutrophication Management and Climatic Effects: An Integrative Approach

Stuckenia pectinata, a submerged macrophyte of eutrophic to hyper-eutrophic fresh to brackish waters, faces management and climatic-forced increment of salinity and irradiance in Vistonis Lake (Greece) that may endanger its existence and the ecosystem functioning. A pre-acclimated clone under low irradiance and salinity conditions was treated to understand the effects of high salinity and irradiance on a suite of subcellular (chlorophyll a fluorescence kinetics and JIP-test, and chlorophyll content) to organismal (relative growth rate—RGR) physiological parameters. The responses to high irradiance indicated the plant’s great photo-acclimation potential to regulate the number and size of the reaction centers and the photosynthetic electron transport chain by dissipation of the excess energy to heat. A statistically significant interaction (p &lt; 0.01) of salinity and irradiance on Chl a, b content indicated acclimation potential through adjusting the Chl a, b contents. However, no significant (p &gt; 0.05) difference was observed on Chl a/b ratio and the RGR, indicating the species’ potential to become acclimatized by reallocating resources to compensate for growth. Thus, the regulation of photosynthetic pigment content and photosystem II performance consisted of the primary growth strategy to present and future high salinity and irradiance stressful conditions due to eutrophication management and the ongoing climatic changes.

Droplet migration into dead-end channels at high salinity enhanced by micelle gradients of a zwitterionic surfactant

Colloidal migration driven by electrolyte gradients is often reported in low-salinity conditions. Applying such a concept in high salinity conditions, however, is quite challenging due to the deteriorated colloidal stability and quenched electrostatic interaction. Here, droplet migration in high salinity is induced by the gradient of a zwitterionic surfactant that also stabilizes the emulsion. The reported emulsion system and mobilization strategy allow encapsulation and enhanced delivery of chemical agents for many subsurface applications.

Supplementation of Ex-Situ Biofloc to Improve Growth Performance and Enhance Nutritional Values of the Pacific White Shrimp Rearing at Low Salinity Conditions

Shrimp is an important food source consumed worldwide. An intensive aquaculture system with overuse of feed in combination with detrimental effects from climate change are serious problems leading to mass mortality of cultured shrimp. Biofloc technology is an approach to managing water quality and controlling the disease to counter the negative side of intensive culture system; however, most of the biofloc applications are naturally formed, which could be inconsistent. In this study, we employed an established optimal ratio of microbial consortium called “ex-situ biofloc (BF)” to be used as a feed supplement in shrimp cultured in a zero-water discharged system at low salinity conditions. Three feeding groups (100%commercial pellet (C), 95%C+BF, 90%C+BF) of shrimp were cultured for six weeks. The effect of an ex-situ biofloc supplement with commercial pellet reduction showed that levels of ammonium, nitrite, nitrate and phosphate were significantly decreased in water culture. Shrimp fed with ex-situ biofloc supplement with commercial pellet reduction exhibited significantly increased shrimp weight and survival, and significantly expressed growth-related genes involving lipolysis and energy metabolism higher than those fed with 100% commercial pellet. Nutritional analysis indicated a significant increase of docosahexaenoic acid (DHA) and eicosenoic acid (C20:1) concentrations in the ex-situ biofloc supplemented shrimp. This finding revealed the potential of ex-situ biofloc to manage water quality, improve shrimp growth performance and enhance shrimp nutritional value under intensive culture at low salinity conditions. The beneficial effects of the ex-situ biofloc in shrimp culture system make it a promising alternative strategy to mitigate climate change effects leading to the sustainable production of high-quality shrimp in the future.

Modulation of fatty acid profiles by global and local ocean change drivers in the ragworm Hediste diversicolor: implications for aquaculture production

Global change projections predict significant impacts on the aquaculture sector leading to a substantial interest in the study of species' ecophysiological responses to increased temperature and shifting salinities. Here, we experimentally evaluated shifts on the fatty acid (FA) profiles of the ragworm Hediste diversicolor under global and local ocean change drivers. This polychaete is a suitable extractive organism for integrated multi-trophic aquaculture (IMTA) designs, as it maximizes the use of otherwise wasted nutrients present in particulate organic matter of farm effluents. Ragworms were collected from intertidal mudflats and subjected to an experimental trial of 28 days under control (24 °C), warming (27 °C) and heatwave (30 °C) scenarios combined with salinity variations (20 and 30) in a full factorial design. Individuals were sampled after 14 and 28 days of exposure (D14 and D28 respectively) for FA profile analysis. Interactions between temperature x day and salinity x day modulated ragworms' fatty acid profiles. Overall, an increase in different FA classes, as well as in ∑n-3 UFA, ∑n-6 UFA and essential fatty acids (EFA) was detected over time in polychaetes exposed to salinity 30, contrary to what was observed in salinity 20. This suggests that salinity 30 is an optimal condition for H. diversicolor FA enrichment. At this salinity, fatty acids from n-3 and n-6 families remained stable at 24 °C and 27 °C, with a decrease being detected at 30 °C (after 14 days of exposure), possibly related to changes in the lipid composition of cell membranes to maintain homeostasis. However, after 28 days, no differences were detected, suggesting that polychaetes can acclimate to elevated temperatures when they are in optimal salinity conditions. In contrast, if an extreme warm event (30 °C) is combined with low salinity (20), all FA classes increase at day 14 and HUFA class remain elevated after 28 days, while ∑n-3 UFA, ∑n-6 UFA, ARA, EPA and DHA decrease, suggesting their potential role in osmotic balance and membrane fluidity. Still, if ragworms are grown at low salinity and the increase in temperature is only moderate, ∑n-3 UFA, ∑n-6 UFA, ARA, EPA and DHA increase. This study shows that heatwaves can have an impact on H. diversicolor aquaculture, especially under low salinity conditions, by decreasing EFA. Risk assessment and adaptation strategies need to be implemented into aquaculture practices to mitigate the impacts of global change on the nutritional profile of farmed species and their overall commercial value.

Effect of pH on interfacial tension reduction of oil (Heavy acidic crude oil, resinous and asphaltenic synthetic oil)/low salinity solution prepared by chloride-based salts

Chloride salts of NaCl, KCl, CaCl 2 , and MgCl 2 are among the essential salts examined for enhanced oil recovery (EOR) purposes through chemical injection, low salinity injection, smart water injection, etc. These salts are crucial for EOR studies since they exist in the reservoir with undeniable effects on interfacial tension (IFT), wettability alteration, etc. The alkaline injection that can produce in-situ soap leading to lower IFT values can be combined with low salinity injection method to form the hybrid EOR method. Among the different parameters in alkaline flooding, the aqueous solution pH is essential, since there is a strong relationship between the pH of the solution and crude oil type for ionization and generating in-situ soap. Whit this parameter, the current investigation concentrated on the effect of chloride-based salt (with a concentration of 5000 ppm to mimic the low salinity condition) at different pH values of 3.5, 7, and 11 in contact with heavy acidic crude oil (HACO). Since resin and asphaltene have a surfactant nature, resinous synthetic oil (8 % wt/wt) (RSO) and asphaltenic synthetic oil (8 % wt/wt) (ASO) were prepared by dissolving isolated resin and asphaltene using IP/140 procedure and examined. The results show that IFT can reduce to a value of 0.4 and 2.5 mN.m-1 for pH of 11 and DW solution if RSO and HACO utilize. The results also reveal that among the examined salts, NaCl and KCl introduce the highest impact for all types of model oils at pH values of 11, while no significant effect for pH values of 3.5 and 7 was obtained. According to these findings, it seems that injecting alkaline chemicals such as NaOH (which enhances aqueous solution pH) is an effective way to reduce the IFT values due to the in-situ surfactant generation and saponification of organic acids exited in model oils. Additionally, the IFT values show that although salts can retard the IFT reduction to some extent, no significant negative influence on the IFT reduction trends exist for the case of NaCl and KCl. • Increasing pH from 3.5 to 11 significantly reduces the IFT values for Heavy acidic crude oil. • Increasing pH from 3.5 to 11 significantly reduce the IFT value especially for resinous synthetic oil. • Chloride salts except CaCl2 introduce positive effects on IFT for pH values of 3.5 and 7. • Chloride salts introduce negative effects on the IFT for pH value of 11. • Increasing pH can generate in-situ surfactants by saponification.

Pipefish Locally Adapted to Low Salinity in the Baltic Sea Retain Phenotypic Plasticity to Cope With Ancestral Salinity Levels

Genetic adaptation and phenotypic plasticity facilitate the migration into new habitats and enable organisms to cope with a rapidly changing environment. In contrast to genetic adaptation that spans multiple generations as an evolutionary process, phenotypic plasticity allows acclimation within the life-time of an organism. Genetic adaptation and phenotypic plasticity are usually studied in isolation, however, only by including their interactive impact, we can understand acclimation and adaptation in nature. We aimed to explore the contribution of adaptation and plasticity in coping with an abiotic (salinity) and a biotic (Vibriobacteria) stressor using six different populations of the broad-nosed pipefishSyngnathus typhlethat originated from either high [14–17 Practical Salinity Unit (PSU)] or low (7–11 PSU) saline environments along the German coastline of the Baltic Sea. We exposed wild caught animals, to either high (15 PSU) or low (7 PSU) salinity, representing native and novel salinity conditions and allowed animals to mate. After male pregnancy, offspring was split and each half was exposed to one of the two salinities and infected withVibrio alginolyticusbacteria that were evolved at either of the two salinities in a fully reciprocal design. We investigated life-history traits of fathers and expression of 47 target genes in mothers and offspring. Pregnant males originating from high salinity exposed to low salinity were highly susceptible to opportunistic fungi infections resulting in decreased offspring size and number. In contrast, no signs of fungal infection were identified in fathers originating from low saline conditions suggesting that genetic adaptation has the potential to overcome the challenges encountered at low salinity. Offspring from parents with low saline origin survived better at low salinity suggesting genetic adaptation to low salinity. In addition, gene expression analyses of juveniles indicated patterns of local adaptation,trans-generational plasticity and developmental plasticity. In conclusion, our study suggests that pipefish are locally adapted to the low salinity in their environment, however, they are retaining phenotypic plasticity, which allows them to also cope with ancestral salinity levels and prevailing pathogens.

Influence of oil droplet behavior in electrochemical micromembrane cells on treating oil/water emulsions with low-salt concentrations

Although flow-through electrode has demonstrated its potential in treating oily wastewater, few studies noted influence of oil droplet behavior on treating oil/water emulsions. In order to explore the influence of oil droplet behavior in a flow-through electrode cell on treating oil/water emulsions with low-salt concentrations, an electrochemical micromembrane cell was applied to treat oil/water emulsions with 0–0.8 g/L NaCl. High chemical oxygen demand (COD) reduction (80–90%) was obtained in treating Sodium dodecylbenzene sulfonate (SDBS) or Tween 80 emulsion by flow-through electrode, while the later had the higher permeate flux (900 mL/min around). The low salt concentration (0.5 g/L NaCl) achieved high COD reduction (87%) and good permeate flux (600 mL/min). Observations using optical microscopy revealed severe deformation of the shape of the charged oil droplet at the flow-through electrode interface. The wetting of oil droplets at the electrode interface occurred when the membrane acted as an anode, which resulted in flow-through electrode fouling, and subsequently, the reduction in permeate flux and treatment efficiency. The results of this study offer an attractive option when using flow-through electrode to treat oil-in-water emulsions under low-salinity conditions.

Species‐specific responses of a marsh‐forest ecotone plant community responding to climate change

Ecotones are responsive to environmental change and pave a path for succession as they move across the landscape. We investigated the biotic and abiotic filters to species establishment on opposite ends of a tidal marsh-forest ecotone that is moving inland in response to sea level rise. We transplanted four plant species common to the ecotone to the leading or trailing edge of the migrating ecotone, with and without caging to protect them from ungulate herbivores. We found that species exhibited an individualistic response to abiotic and biotic pressures in this ecotone; three species performed better at the leading edge of the ecotone in the coastal forest, whereas one performed better at the trailing edge in the marsh. Specifically, grass species Phragmites australis and Panicum virgatum grew more in the low light and low salinity conditions of the leading edge of the ecotone (forest), whereas the shrub Iva frutescens grew better in the high light, high salinity conditions of the trailing edge of the ecotone (marsh). Furthermore, of the four species, only P. australis was affected by the biotic pressure of herbivory by an introduced ungulate, Cervus nippon, which greatly reduced its biomass and survival at the leading edge (forest). P. australis is an aggressive invasive species and has been observed to dominate in the wake of migrating marsh-forest ecotones. Our findings detail the role of lower salinity stress to promote and herbivory pressure to inhibit the establishment of P. australis during shifts of this ecotone, and also highlight an interaction between two non-native species, P. australis and C. nippon. Understanding migration of the marsh-forest ecotone and the factors controlling P. australis establishment are critical for marsh conservation in the face of sea level rise. More generally, our findings support the conclusion that the abiotic and biotic filters of a migrating ecotone shape the resulting community.

Exploration of data on the formation of two mangrove seedling species to establish a growing stability point

Avicennia alba is one of the best mangrove colonies. A. alba seems to adapt well to grow stably on dynamic flat mud. A. alba species through their root growth, vare able to rely on sediments quickly, resist the hydrodynamic force of waves and tidal currents within a few days and then withstand the movement of sediments in the upper sedimentary layers. While from Ceriops tagal propagules and Rhizophora mucronata, after falling from the mother tree, certain dehydration levels stimulate the initiation of root formation as a sign to show dormancy propagules. As a result, root formation cis delayed when propagules float in the sea during dispersal. Meanwhile, the formation phase of mangrove propagules is faster in conditions of low salinity than in conditions of high salinity, and if during the rainy season, conditions for propagules’ information are better. However, these two species follow different strategies for the distribution and formation of mangrove zoning, and these findings contribute to the explanation of the distribution of different species.