High Salinity Environment Research Articles

Consistency guaranteed two-timescale decision and optimization of HVAC system with ice storage

Nuclear power is the world’s largest source of clean energy. Nowadays the capacity shortage of electricity market for consuming nuclear power has appeared. Meanwhile, under the unique environment of high humidity and high salinity of nuclear power plant, the environment should be improved to ensure staff comfort and equipment safe operation through heating, ventilation, and air conditioning (HVAC) system. The joint operation of nuclear power and ice storage should be encouraged. Using nuclear power to provide electricity, the ice storage uses cheap off-peak electricity to make ice and uses the ice for supplemental cooling during peak demand time. The ice storage also provides a way to shift a large amount of electricity from off-peak time to peak time. With the objective of minimizing the electricity cost, while keeping the indoor temperatures of nuclear power plant near the desired temperatures, a two-timescale model of HVAC system with ice storage is proposed in this paper. Simulation results show that the proposed model can guarantee the consistency in different timescales, and meet the user desired temperature for comfort with the electricity cost reduced.

Role of Ecohydrographical Barriers on the Spatio-Temporal Distribution of Chaetognath Community in the Gulf of Aqaba during Summer

The Gulf of Aqaba (GoA), positioned between the Sinai Peninsula and the Saudi Arabian coast is characterized by its uniquely high saline, oligotrophic waters, and seasonally stratified hydrography. Despite its geographical significance, information on its zooplankton ecology and biodiversity is still meager. Hence, the present study was aimed to investigate the detailed diversity and ecology of the dominant carnivorous zooplankton taxon chaetognath in the pelagic waters of the GoA during summer. Despite the known water flow exchange between the GoA and the Red Sea, only five chaetognath species were observed in GoA which is markedly less than the number earlier recorded in the Red Sea, indicating the role of high saline water mass as an ecophysiological boundary for the inhabitance of many epipelagic chaetognaths. Euryhaline, Serratosagitta pacifica formed the dominant species in both the surface water and the upper 200 m water column and was observed to be the most suitable representative of this high saline environment. Conspicuous diel variability in the distribution of the different growth stages of chaetognaths in the surface waters can be attributed to their varied susceptibility to visually oriented predators. The positive relation observed in the abundance of chaetognaths and their main prey, copepods, and their carbon and nitrogen contents indicated their significance in the pelagic trophic ecology of the GoA. The present study, providing the ecology of a major zooplankton taxon of this unique basin will be relevant for understanding the ecology and trophodynamics of the zooplankton community of the GoA.

Diversity of prokaryotic microorganisms in alkaline saline soil of the Qarhan Salt Lake area in the Qinghai\u2013Tibet Plateau

The composition of microbial communities varies considerably across ecological environments, particularly in extreme environments, where unique microorganisms are typically used as the indicators of environmental conditions. However, the ecological reasons for the differences in microbial communities remain largely unknown. Herein, we analyzed taxonomic and functional community profiles via high-throughput sequencing to determine the alkaline saline soil bacterial and archaeal communities in the Qarhan Salt Lake area in the Qinghai–Tibet Plateau. The results showed that Betaproteobacteria (Proteobacteria) and Halobacteria (Euryarchaeota) were the most abundant in the soils of this area, which are common in high salinity environments. Accordingly, microbes that can adapt to local extremes typically have unique metabolic pathways and functions, such as chemoheterotrophy, aerobic chemoheterotrophy, nitrogen fixation, ureolysis, nitrate reduction, fermentation, dark hydrogen oxidation, and methanogenesis. Methanogenesis pathways include hydrogenotrophic methanogenesis, CO2 reduction with H2, and formate methanogenesis. Thus, prokaryotic microorganisms in high salinity environments are indispensable in nitrogen and carbon cycling via particular metabolic pathways.

Thermophilic adsorption of Pb2+ onto bacterium from deep-sea hydrothermal vent

Hydrothermal vents bacteria naturally adapted to high temperature and high salinity environments may provide a new idea for the treatment of industrial wastewater with extreme conditions. In this study, a high-salinity and high-temperature resistance bacteria, Pseudomonas sp. 4–2 was isolated from a deep-sea hydrothermal vent, and proved having good adsorption efficiency for Pb2+ through batch experiments. The maximum adsorption capacity of Pb2+ was 226.24 mg/g at 55 ℃ for active cells, while it was 204.91 mg/g for inactivated cells at 35 ℃ (5% w/v NaCl, pH 6.0 and 0.2 g/L biosorbent dose). The adsorption was a spontaneous endothermic reaction that had the best fit with Langmuir isotherm model and the pseudo-second-order kinetic model. The biosorption process was studied by SEM-EDS, TEM, XRD, XPS, VTIS and 2D-COS analysis, showing that PbS and Pb(OH)2 precipitates were mainly species formed during the adsorption process, and the percentage of PbS was significantly higher than Pb(OH)2. For the molecular structure of the strain 4–2, the respond degree from large to small was lipids, polysaccharides and proteins, the response sequence was proteins, lipids and polysaccharides. The molecular structure of polysaccharides may be the main factor affecting the thermostability and adsorption efficiency at high temperatures. Diffusion, surface adsorption, micro-precipitation, complexation and intracellular accumulation (only active cells) were involved in the adsorption process. Pseudomonas sp. 4–2 may expand the bacterial resource library for microbial remediation and facilitate the development of novel treatment method for extreme industrial wastewater.

Insights into the multiple applications of modified polyacrylamide as oilfield corrosion inhibitor and water phase tackifier

In order to obtain a multifunctional oilfield agent with both corrosion inhibition and oil displacement functions, a polymer with benzene ring structures is synthesized based on polyacrylamide (PAM) and used as inhibitor for the first time. Methods including electrochemistry, weight loss and theoretical calculations are used to study the inhibition effect for P110 steel in 1.0 M HCl. The experimental results show that the modified polymer poly-(Z)-N-benzylidenepropionamide (PBAM) has excellent inhibition effects, and the maximum efficiency can reach 90.62% in impedance spectroscopy tests. The benzene ring structure added in the modified polymer provides π electrons for the adsorption of inhibitor on metal surface, strengthens the adsorption, and thus brings a better corrosion inhibition effect. In addition to the corrosion inhibition performance, the viscosity-increasing effect of PBAM is evaluated. The results show that the addition of benzene ring not only enhances the corrosion inhibition effect, but also brings temperature resistance to the polymer. However, the salt tolerance of the polymer is affected, the synthesized PBAM which viscosity can above 500 mPa s at 140 °C is suitable for high temperature and low salinity environment. The modified polyacrylamide has satisfactory corrosion inhibition and oil displacement performance, which provides a new idea for the development of oilfield chemistry.

Genome-Wide Analysis of Alternative Splicing (AS) Mechanism Provides Insights into Salinity Adaptation in the Livers of Three Euryhaline Teleosts, including Scophthalmus maximus, Cynoglossus semilaevis and Oncorhynchus mykiss.

Simple SummaryAlternative splicing (AS) is a key post-transcriptional regulatory mechanism that acts an important regulator in response to environmental stimuli in organisms. In the present study, 18 RNA-Seq datasets were utilized to investigate the potential roles of AS in response to different salinity environments in the livers of three euryhaline teleosts, including turbot (Scophthalmus maximus), tongue sole (Cynoglossus semilaevis) and steelhead trout (Oncorhynchus mykiss). The results indicated that different salinity environments changed the splicing patterns of numerous RNA splicing regulators, which might affect the splicing decisions of many downstream target genes in response to salinity changes. This study provides preliminary evidence for the important roles of AS events in salinity adaptation in teleosts.Salinity is an important environmental factor that directly affects the survival of aquatic organisms, including fish. However, the underlying molecular mechanism of salinity adaptation at post-transcriptional regulation levels is still poorly understood in fish. In the present study, 18 RNA-Seq datasets were utilized to investigate the potential roles of alternative splicing (AS) in response to different salinity environments in the livers of three euryhaline teleosts, including turbot (Scophthalmus maximus), tongue sole (Cynoglossus semilaevis) and steelhead trout (Oncorhynchus mykiss). A total of 10,826, 10,741 and 10,112 AS events were identified in the livers of the three species. The characteristics of these AS events were systematically investigated. Furthermore, a total of 940, 590 and 553 differentially alternative splicing (DAS) events were determined and characterized in the livers of turbot, tongue sole and steelhead trout, respectively, between low- and high-salinity environments. Functional enrichment analysis indicated that these DAS genes in the livers of three species were commonly enriched in some GO terms and KEGG pathways associated with RNA processing. The most common DAS genes work as RNA-binding proteins and play crucial roles in the regulation of RNA splicing. The study provides new insights into uncovering the molecular mechanisms of salinity adaptation in teleosts.

Expression of Genes Related to Plant Hormone Signal Transduction in Jerusalem Artichoke (Helianthus tuberosus L.) Seedlings under Salt Stress

Background: Jerusalem artichoke (Helianthus tuberosus L.) is moderately tolerant to salinity stress and has high economic value. The salt tolerance mechanisms of Jerusalem artichoke are still unclear. Especially in the early stage of Jerusalem artichoke exposure to salt stress, gene transcription is likely to undergo large changes. Previous studies have hinted at the importance of temporal expression analysis in plant transcriptome research. Elucidating these changes may be of great significance to understanding the salt tolerance mechanisms of it. Results: We obtained high-quality transcriptome from leaves and roots of Jerusalem artichoke exposed to salinity (300 mM NaCl) for 0 h (hour), 6 h, 12 h, 24 h, and 48 h, with 150 and 129 unigenes and 9023 DEGs (differentially expressed genes). The RNA-seq data were clustered into time-dependent groups (nine clusters each in leaves and roots); gene functions were distributed evenly among them. KEGG enrichment analysis showed the genes related to plant hormone signal transduction were enriched in almost all treatment comparisons. Under salt stress, genes belonging to PYL (abscisic acid receptor PYR/PYL family), PP2C (Type 2C protein phosphatases), GH3 (Gretchen Hagen3), ETR (ethylene receptor), EIN2/3 (ethylene-insensitive protein 2/3), JAZ (genes such as jasmonate ZIM-domain gene), and MYC2 (Transcription factor MYC2) had extremely similar expression patterns. The results of qRT-PCR of 12 randomly selected and function known genes confirmed the accuracy of RNA-seq. Conclusions: Under the influence of high salinity (300 mM) environment, Jerusalem artichoke suffer serious damage in a short period of time. Based on the expression of genes on the time scale, we found that the distribution of gene functions in time is relatively even. Upregulation of the phytohormone signal transduction had a crucial role in the response of Jerusalem artichoke seedlings to salt stress, and the genes of abscisic acid, auxin, ethylene, and jasmonic acid had the most obvious change pattern. Research emphasized the regulatory role of hormones under high salt shocks and provided an explorable direction for the study of plant salt tolerance mechanisms.

Research Progress on The Effects of Salt Stress on Photosynthesis and Lipids of Microalgae

High salinity, temperature, light intensity, and cold environment are generally sensitive to higher plants. These pressures are a challenging environmental stress for plant growth and distribution. High salinity is an environmental stress for organisms to overcome. Due to their attractive properties, microalgae are important freshwater algae, widely used for human and animal, food source and industrial applications. This review summaries the progress on the effects of microalgae’s photosynthesis and lipid content by salinity. At the same time, the application value of microalgae is briefly summarized.

Geopolymer as the future oil-well cement: A review

The petroleum and cement manufacturing industries have been accused of contributing substantial quantities of carbon dioxide (CO 2 ) into the atmosphere. Additionally, Portland cement systems suffer carbonation and degradation in high saline and acidic environments. Geopolymer, a much cleaner cementitious binder, synthesized through the reaction of aluminosilicate materials and alkaline solution has been a leading alternative to ordinary Portland cement (OPC). The feasibility of using geopolymer in oil-well cementing is still being explored. The objective of this review study is to provide a single document that summarizes the findings from these studies. In general, researchers have explored geopolymer application in aggressive environments and well plug and abandonment operations, the effect of temperature, and its compatibility with drilling fluid. Compared to OPC systems, geopolymer is more resistant to acidic environments, performs better in high saline conditions, and is highly compatible with drilling mud. The geopolymer being a green technology coupled with its optimized properties implies that it is the future of oil-well cement. For further studies, we suggest in-depth characterization of lightweight geopolymers. • The state of research on the application of geopolymer for oil well cementing has been explored. • Geopolymer overcomes many of the issues faced with ordinary Portland cement (OPC). • Geopolymer would be an excellent alternative to OPC-based systems.

Paleoenvironments and Hydrocarbon Potential of Upper Cretaceous Shales in Agbabu-1 Well, Dahomey Basin – Insight from Geochemistry and Foraminifera Paleontology

Upper Cretaceous shales partially exposed in the northern fringes of the Dahomey Basin are well developed in the subsurface in Southwestern part of the basin where Agbau-1 well is sited. These shales were evaluated in respect to their paleoenvironments and potentials for hydrocarbon using foraminiferal assemblages, biomarkers and Rock Eval pyrolysis studies. The dominance of benthonic foraminifera species suggests a shallow marine environment and high percentage of calcareous to arenaceous benthic www.eujournal.org 195 foraminifera indicate high water salinity and hypersline environment. Dysoxic oxygen condition is also prevalent probably because most of the benthic foraminifera recovered are epifauna that live in a reduced oxygen condition. 1.90 wt%, 244 mgHC/gTOC and 429℃ average values of total organic carbon, hydrogen index and Tmax reveal that the Upper Cretaceous shales have relatively fair to good organic matter, predominantly Type II-III kerogen and currently immature. Though three is a trend of an increase in maturity down the hole. All the steranes have uniform distributions (C27>C28>C29), suggesting a relatively higher input from the marine red algae and a low level of land plant contribution to the source organic matter. Pristane/phytane ratios and C29/C27 steranes confirmed the organic matter type to be a Type II/III and anoxic source rock depositional condition as well as a reducing diagenetic system in the sediment water column. The Upper Cretaceous shales in Dahomey Basin can be targeted for exploration as an unconventional petroleum resource.

Photosynthesis in response to salinity and submergence in two Rhizophoraceae mangroves adapted to different tidal elevations.

Mangrove ecosystems are vulnerable to rising sea levels. When the sea level rises, the plants are exposed to increased salinity and tidal submergence. In Taiwan, the mangrove species Kandelia obovata and Rhizophora stylosa grow in different habitats and at different elevations. To understand the response of photosynthesis to salinity and submergence in mangroves adapted to different tidal elevations, gas exchange and chlorophyll fluorescence parameters were measured in K. obovata and R. stylosa under different salinity (20 and 40‰) and submergence treatments. The period of light induction of photosynthesis for the two mangrove species was >60min. In the induction process, the increase in photosystem efficiency was faster than the increase in stomatal opening, but CO2 fixation efficiency was restricted by stomatal conductance. The constraint of stomatal opening speed is related to the conservative water-use strategy developed in response to mangrove environments. Submergence increased the photosynthetic rate of K. obovata, but not that of R. stylosa. Although R. stylosa was more salt tolerant than K. obovata, R. stylosa was not submergence tolerant in a high-salinity environment, which may be the reason for the higher intertidal elevations observed for R. stylosa in comparison with K. obovata. The photosynthetic rate and energy-dependent quenching (qE) of the two mangroves presented a negative relationship with photoinhibition, and high-salt treatment simultaneously reduced photosynthetic rate and qE. A decrease in the photosynthetic rate increased excess energy, whereas a decrease in qE decreased photoprotection; both increased photoinhibition. As the degree of photoinhibition can be easily measured in the field, it is a useful ecological monitoring index that provides a suitable reference for mangrove restoration, habitat construction and ecological monitoring.

An endoplasmic reticulum–localized cytochrome b5 regulates high-affinity K+ transport in response to salt stress in rice

Potassium (K+) is an essential element for growth and development in both animals and plants, while high levels of environmental sodium (Na+) represent a threat to most plants. The uptake of K+ from high-saline environments is an essential mechanism to maintain intracellular K+/Na+ homeostasis, which can help reduce toxicity caused by Na+ accumulation, thereby improving the salt tolerance of plants. However, the mechanisms and regulation of K+-uptake during salt stress remain poorly understood. In this study, we identified an endoplasmic reticulum-localized cytochrome b5 (OsCYB5-2) that interacted with a high-affinity K+ transporter (OsHAK21) at the plasma membrane. The association of OsCYB5-2 with the OsHAK21 transporter caused an increase in transporter activity by enhancing the apparent affinity for K+-binding but not Na+-binding. Heme binding to OsCYB5-2 was essential for the regulation of OsHAK21. High salinity directly triggered the OsHAK21-OsCYB5-2 interaction, promoting OsHAK21-mediated K+-uptake and restricting Na+ entry into cells; this maintained intracellular K+/Na+ homeostasis in rice cells. Finally, overexpression of OsCYB5-2 increased OsHAK21-mediated K+ transport and improved salt tolerance in rice seedlings. This study revealed a posttranslational regulatory mechanism for HAK transporter activity mediated by a cytochrome b5 and highlighted the coordinated action of two proteins to perceive Na+ in response to salt stress.

Source analysis and health risk assessment of groundwater pollution based on multivariate statistical techniques in Kashgar Delta Area, Xinjiang, China.

In this study, 63 groundwater samples were collected in the Kashgar Delta Area in Xinjiang in 2016, and then, the samples were tested and the test results were analyzed. Multivariate statistical techniques were used to determine the sources of pollution, and the USEPA (United States Environmental Protection Agency) model was used to assess the long-term health risk of groundwater to adults and children in the study area. The concentrations of groundwater chemical Na+, Cl-, SO42-, NH4+-N, TDS, F-, I-, As, Fe, Mn, Pb, Hg, pH, TH, and CODMn, which exceed the permissible level in the study based on groundwater quality index and possibly pose a potential threat to the health of the residents in the area, which are mainly influenced by geological conditions. The source of the pollutants is the dissolution of minerals in the aquifer medium, which is greatly affected by the high-salinity groundwater environment, pH conditions, redox conditions, and evaporation and concentration effect. The values of the noncarcinogenic health risk index HQn follow the descending order of Cl- > F- > As > Fe > Mn > Pb > Hg > NH4+-N; There are eight nonarcinogens and one carcinogen in groundwater of which Cl- is the dominant noncarcinogenic factor, while As is the main carcinogenic pollutant in the study area. The health risk ratio results show that Cl- and As are the main pollutants that pose the greatest threat to both adults' and children's health, and they should be considered as the primary indicators for health risk management and control.

Insulin signaling and osmotic stress response regulate arousal and developmental progression of C. elegans at hatching.

The progression of animal development from embryonic to juvenile life depends on the coordination of organism-wide responses with environmental conditions. We found that two transcription factors that function in interneuron differentiation in Caenorhabditis elegans, fax-1, and unc-42, are required for arousal and progression from embryogenesis to larval life by potentiating insulin signaling. The combination of mutations in either transcription factor and a mutation in daf-2 insulin receptor results in a novel perihatching arrest phenotype; embryos are fully developed but inactive, often remaining trapped within the eggshell, and fail to initiate pharyngeal pumping. This pathway is opposed by an osmotic sensory response pathway that promotes developmental arrest and a sleep state at the end of embryogenesis in response to elevated salt concentration. The quiescent state induced by loss of insulin signaling or by osmotic stress can be reversed by mutations in genes that are required for sleep. Therefore, countervailing signals regulate late embryonic arousal and developmental progression to larval life, mechanistically linking the two responses. Our findings demonstrate a role for insulin signaling in an arousal circuit, consistent with evidence that insulin-related regulation may function in control of sleep states in many animals. The opposing quiescent arrest state may serve as an adaptive response to the osmotic threat from high salinity environments.

Isolation and amplification of mangrove plants using DNA barcode in Percut Sei Tuan, North Sumatra, Indonesia

Mangroves are a collection of several species of trees or shrubs that distribute around the coastline and can survive in high salinity environments. Around 60% of mangrove forests in North Sumatra are reported to have been damaged, the main factors of this damage being the mangrove forests conversion into ponds and the expansion of oil palm plantations. Identification of mangrove species is very important in protecting and applying the biodiversity of mangrove forests. Identification of living things has evolved from morphological charcetrization to molecular identification. This study aims to explain the DNA isolation and PCR methods to identify mangrove species in North Sumatra. The results suggested that the rbcL primer used can detect mangrove species that were visualized in the form of DNA bands. The length of DNA fragments of mangrove species Acrosticum aureum ranged 632.0-619.6 bp, species Rhizophora apiculata 619.6-585.8 bp, species Nypa fruticans 600- 592.9 bp, species Avicennia alba 549.1-533.5 bp, species Hibiscus tiliaceus was not detected, and mangrove species Acanthus ilicifolius 480.3 bp.

Foamability and stability of anionic surfactant-anionic polymer solutions: Influence of ionic strength, polymer concentration, and molecular weight

A systematic experimental approach was initiated to optimize properties of a polymer enhanced foam (PEF) system using anionic surfactant (i.e., AOS) and anionic polymer (i.e., SAV10 MPM) in high salinity conditions. First, the bulk foam properties of AOS surfactant solutions as a function of AOS concentration and salinity were evaluated. The result indicated that Ca2+ ions increased the AOS foamability and foam stability more than Mg2+ ions within the solubility limit, where only the divalent ionic strength (Mg2+/Ca2+) ratio varied within brine composition. Second, the effect of SAV10 MPM concentration and different molecular weights of this polymer on AOS foamability and foam stability were investigated in modified synthetic seawater (MSSW1). We found that the AOS foamability and foam stability improved by SAV10 MPM addition but it's highly dependent on the polymer concentration. The AOS foamability and foam stability were boosted when the polymer concentration was below the critical overlap concentration (c*) in comparison to AOS without polymer. However, above polymer c*, the polymer tends to exhibit antifoam characteristics due to the hydrophobic nature of the polymer. Hence, to enhance anionic-anionic PEF systems, one should inhibit the hydrophobic interaction by maintaining the polymer concentration below c*. Thus, we recommend a low concentration of sulfonated polymer (i.e., SAV10 series, below c*) to enhance the AOS foamability and foam stability in a high salinity environment regardless of viscosity and molecular weight.

A low-cost photo-evaporation inorganic membrane preparation and treatment of the simulated high salinity radioactive waste water

Solar-driven desalination is an energy-saving and environmentally benign wastewater treatment technology. A method of in situ self-reduction of graphene oxide (rGO) by cheap geopolymer was introduced, and a photo evaporation membrane device (rGOPGC) for treatment of the simulated high salt liquid radioactive waste (HSLRW) was prepared in the present study. Compared with other rGO based photo evaporation membrane materials, geopolymer matrix has the advantages of low cost, reductant free, simple preparation process and mild conditions. After desalination of simulated seawater, the concentrations of Na+, K+, Ca2+ and Mg2+ ions reached the WHO standard, and the removal rates of radioactive I-, Cs+ and Sr2+ in the simulated high salinity wastewater reached 99.62%, 99.71% and 99.99% respectively; The evaporation rate of rGOPGC remained stable at 1.5 kg/m2/h after 16 cycles in high salinity environment. There was no obvious salt accumulation on the upper surface of the device, indicating its high stability. Furthermore, the evaporation performance at high temperature near the nuclear power plant (NPP) waste water was simulated and tested. Under one solar intensity and 35 °C ambient temperature, the evaporation rate of 1.75 kg/m2/h and the evaporation efficiency of 98.51% were achieved. The results indicated that the rGOPGC device is potential in the concentration evaluation of HSLRW.

Design of a salt-tolerant Gemini viscoelastic surfactant and the study of construction of wormlike micelle structure in high-salinity aqueous environment

Herein, a zwitterionic Gemini VES (named VES-C) with double ultra-long hydrophobic tails was designed and synthesized which aimed to construct WLM net-structures in high-salinity aqueous solution. Due to the carboxylic group on the spacer, it exhibits partial carboxyl betaine properties and performs well in high salinity environment. Molecular dynamic simulation was carried out and RDF curves were analyzed to predict and explain the mechanism of salinity tolerance of VES-C. Compared with cationic Gemini VESs, a series of experiments were conducted by varying salinity, including surface tension, DLS, 1H NMR and fluorescent probe, to explain the salt-tolerance mechanism of VES-C. The salinity cloudy point of VES-C surpasses 10 wt%, exhibiting superior salt-tolerance to those cationic Gemini VESs. Trough viscosity measurement, oscillatory measurement and microstructure observation, it proves that VES-C molecules can construct WLM netlike structures within the salinity range from 3 wt% to 10 wt% (optimal salinity: 4 wt%), thus VES-C can be applied as the clean thickener to prepared seawater or brine based fracturing fluid by constructing WLM netlike structure in high salinity aqueous environment, which leaves the preparation of clean fracturing fluid independent of freshwater resources.

Specific network and phylosymbiosis pattern in endophyte community of coastal halophytes

Halophytes colonize stressed environments of high salinity. Endophytic symbionts improve growth performance and thus adaptability of host plants in stressed environments. Nevertheless, studies focused on the distribution and assembly patterns of fungal endophyte assemblages of halophytes in high salinity environments are limited. We selected 27 common non-mangrove halophytes across 4 geographic sites along the eastern coastline of China for our investigation on endophyte assemblages. We found a significant amount of basidiomycetous fungi in the endophyte assemblage. The endophyte community compositions were significantly affected by plant species and geographic locations. Some halophyte hosts showed significant preference for endophytic fungi in host preference analysis. The network structures of host-microbe bipartite graphs at each site had low connection and were highly nested, modular and specialized. Current results also indicated significant correlation and congruency between host phylogeny and compositions of endophyte local communities and meta-community. Our research showed that host is the dominant factor shaping the fungal endophytic communities in aerial tissues of halophytes in high salinity environments, and the host influence on endophytic community relates to plant phylogeny.

High site-fidelity in common bottlenose dolphins despite low salinity exposure and associated indicators of compromised health

More than 2,000 common bottlenose dolphins (Tursiops truncatus) inhabit the Barataria Bay Estuarine System in Louisiana, USA, a highly productive estuary with variable salinity driven by natural and man-made processes. It was unclear whether dolphins that are long-term residents to specific areas within the basin move in response to fluctuations in salinity, which at times can decline to 0 parts per thousand in portions of the basin. In June 2017, we conducted health assessments and deployed satellite telemetry tags on dolphins in the northern portions of the Barataria Bay Estuarine System Stock area (9 females; 4 males). We analyzed their fine-scale movements relative to modeled salinity trends compared to dolphins tagged near the barrier islands (higher salinity environments) from 2011 to 2017 (37 females; 21 males). Even though we observed different movement patterns among individual dolphins, we found no evidence that tagged dolphins moved coincident with changes in salinity. One tagged dolphin spent at least 35 consecutive days, and 75 days in total, in salinity under 5 parts per thousand. Health assessments took place early in a seasonal period of decreased salinity. Nonetheless, we found an increased prevalence of skin lesions, as well as abnormalities in serum biochemical markers and urine:serum osmolality ratios for dolphins sampled in lower salinity areas. This study provides essential information on the likely behavioral responses of dolphins to changes in salinity (e.g., severe storms or from the proposed Mid-Barataria Sediment Diversion project) and on physiological markers to inform the timing and severity of impacts from low salinity exposure.