Salt Water Bodies Research Articles

Assessing the oxidative potential of dust from great salt Lake

Great Salt Lake (GSL) is one of the world's largest inland bodies of saltwater. Climate change, drought, and water diversions have led to the GSL reaching historically low levels, exposing over 1945 km2 of lakebed. Dust events can transport particulate matter (PM) from the GSL's exposed lakebed to the adjacent urban areas, presenting air quality and health concerns. In this study, we assessed the oxidative potential (OP) of dust from the exposed GSL bed compared to dust samples collected from other regional playas and to reference Arizona test dust. The oxidative potential of PM10 (particles ≤10 μm in aerodynamic diameter) derived from these dusts was assessed by two acellular assays: the ascorbic acid (OPAA) and dithiothreitol (OPDTT) and two extraction solvents: phosphate buffer saline and Gamble's simulated lung fluid. All samples were also analyzed for elemental composition. Our results show that the concentration of As and Li in most of the GSL dust samples exceeded the Environmental Protection Agency (EPA) soil residential regional screening levels, and the OPAA and OPDTT of dust samples from GSL playas were generally higher than the OP of other regional playas. Our findings also indicated that the OP of the GSL dust was associated with metals, including Cu, Mn, Fe, and Al. This is the first study evaluating the oxidative potential of dust from the GSL, which improves our understanding of how increasing aridity, particularly desiccation of saline lakes, affects air quality and public health.

Использование данных дистанционного зондирования Земли для анализа межгодовой динамики площади Тениз-Коргалжынских озер

The Teniz-Korgalzhyn lake system has the status of an international Ramsar site and is the most important ornithological center in Central Asia. It includes more than 60 shallow fresh- and salt water bodies among which the largest salt ones are Big and Small Teniz and a group of fresh Korgalzhyn lakes. Fluctuations in water levels there and changes in their area determine the degree of favorable habitat conditions for key ornithological species. A quantitative assessment of the water levels’ interannual dynamics in 2006–2019 was carried out using remote sensing and geoinformation mapping methods. The choice of the methodology to use multispectral data for water surface area study is substantiated. Calculations are made, and a corresponding map of the bodies’ water surface area dynamics is compiled. Four periods with multidirectional dynamics of changes in it were identified. They are caused by both natural and anthropogenic factors and differ in intensity for fresh and salt lakes. Fluctuations of fresh Korgalzhyn ones are mostly associated with natural and climatic impact. Salty Big and Small Teniz are characterized by more significant changes in water surface the area, caused primarily by human activities, including periodic breakthroughs of retaining dams. Maximum deviations towards the increase were noted for fresh ones in 2016–2019, and for saline in 2014–2019. The observed decrease in the total area of the water surface in the period from 2006 to 2013 was mainly associated with the Small and Big Teniz

Experimental Assessment of Survival Rate of Artemia franciscana in Salt Waterbodies of Kazakhstan and Coexistence Possibility with the Local Species Artemia parthenogenetica

Experimental Assessment of Survival Rate of <i>Artemia franciscana</i> in Salt Waterbodies of Kazakhstan and Coexistence Possibility with the Local Species <i>Artemia parthenogenetica</i>

Screening and Characterization of Streptomyces spp. Isolated from Soil Producing a Potential Inhibitors of the Proteus mirabilis

Proteus mirabilis is a common cause of urinary tract infections and other nosocomial infections that can lead to severe health consequences. Despite the availability of various antibiotics, the increasing prevalence of multidrug-resistant (MDR) strains of Proteus mirabilis has necessitated the development of novel therapeutic compounds. The ability of species to produce a wide variety of secondary metabolites, such as antibiotics Streptomyces, immunosuppressants, and antivirals, is well known. In this study, a Streptomyces strain was isolated from soil near saltwater bodies, and its secondary metabolic extract was evaluated for its antimicrobial activity against Proteus mirabilis. The Streptomyces isolate demonstrated significant antimicrobial activity for Proteus mirabilis, with a minimum inhibitory concentration (MIC) of 34 µg/mL. The antimicrobial potential of the extract was confirmed through additional examination of the metabolite extract using deterministic assays, such as nucleic acid and protein release and time-kill curve assay. Molecular identification of the Streptomyces strain showed similarity with Streptomyces triticirhizae. GC-MS analysis of the extract revealed the presence of compounds such as Octadecanoic acid and n-Hexadecanoic acid, which are frequently associated with potent antimicrobial activity. HR-LCMS analysis revealed the presence of compounds such as Neomycin, Polymyxin B, and Maculosin, which also have potent antimicrobial activity. These findings strongly indicate the potential of the Streptomyces metabolite extracts as a novel therapeutic compound against Proteus mirabilis.

Mosquitoes, Lymphatic Filariasis, and Public Health: A Systematic Review of Anopheles and Aedes Surveillance Strategies.

Lymphatic Filariasis (LF) affects over 120 million people in 72 countries, with sub-periodic filariasis common in the Pacific. Wuchereria bancrofti has three physiological races, each with a unique microfilarial periodicity, and each race is isolated to a specific geographical region. Sub-periodic W. bancrofti is transmitted by various Aedes mosquito species, with Aedes polynesiensis and Aedes samoanus being the primary vectors in Samoa. The Aedes scutellaris and Aedes kochi groups are also important vectors in the South Pacific Islands. Anopheles species are important vectors of filariasis in rural areas of Asia and Africa. The Anopheles gambiae complex, Anopheles funestus, and the Anopheles punctulatus group are the most important vectors of W. bancrofti. These vectors exhibit indoor nocturnal biting behaviour and breed in a variety of habitats, including freshwater, saltwater, and temporary water bodies. Effective vector surveillance is central to LF control and elimination programs. However, the traditional Human Landing Collection (HLC) method, while valuable, poses ethical concerns and risks to collectors. Therefore, this review critically analyses alternative trapping tools for Aedes and Anopheles vectors in LF-endemic regions. We looked at 14 research publications that discussed W. bancrofti vector trapping methods. Pyrethrum Spray Catches (PSC), one of the seven traps studied for Anopheles LF vectors, was revealed to be the second most effective strategy after HLC, successfully catching Anopheles vectors in Nigeria, Ghana, Togo, and Burkina Faso. The PSC method has several drawbacks, such as the likelihood of overlooking exophilic mosquitoes or underestimating Anopheles populations. However, exit traps offered hope for capturing exophilic mosquitoes. Anopheles populations could also be sampled using the Anopheles Gravid Trap (AGT). In contrast, the effectiveness of the Double Net Traps (DNT) and the CDC Light Trap (CDC LT) varied. Gravid mosquito traps like the OviArt Gravid Trap (AGT) were shown to be useful tools for identifying endophilic and exophilic vectors during the exploration of novel collection techniques. The Stealth trap (ST) was suggested for sampling Anopheles mosquitoes, although specimen damage may make it difficult to identify the species. Although it needs more confirmation, the Ifakara Tent Trap C design (ITT-C) showed potential for outdoor mosquito sampling in Tanzania. Furvela tent traps successfully captured a variety of Anopheles species and are appropriate for use in a variety of eco-epidemiological settings. By contrast, for Aedes LF vectors, no specific sampling tool was identified for Aedes niveus, necessitating further research and development. However, traps like the Duplex cone trap, Resting Bucket Trap (RB), and Sticky Resting Bucket trap (SRB) proved effective for sampling Aedes albopictus, offering potential alternatives to HLC. This review emphasises the value of looking into alternative trapping methods for Aedes and Anopheles vectors in the LF-endemic region. Further research is required to determine the efficacy of novel collection techniques in various contexts, even if PSC and AGT show promise for sampling Anopheles vectors. The identified traps, along with ongoing research, provide valuable contributions to vector surveillance efforts in LF-endemic regions, enabling LF control and elimination strategies to advance.

Transcriptional landscape of Burkholderia pseudomallei cultured under environmental and clinical conditions.

Burkholderia pseudomallei, a Gram-negative pathogen, is the causative agent of melioidosis in humans. This bacterium can be isolated from the soil, stagnant and salt-water bodies, and human and animal clinical specimens. While extensive studies have contributed to our understanding of B. pseudomallei pathogenesis, little is known about how a harmless soil bacterium adapts when it shifts to a human host and exhibits its virulence. The bacterium's large genome encodes an array of factors that support the pathogen's ability to survive under stressful conditions, including the host's internal milieu. In this study, we performed comparative transcriptome analysis of B. pseudomallei cultured in human plasma versus soil extract media to provide insights into B. pseudomallei gene expression that governs bacterial adaptation and infectivity in the host. A total of 455 genes were differentially regulated; genes upregulated in B. pseudomallei grown in human plasma are involved in energy metabolism and cellular processes, whilst the downregulated genes mostly include fatty acid and phospholipid metabolism, amino acid biosynthesis and regulatory function proteins. Further analysis identified a significant upregulation of biofilm-related genes in plasma, which was validated using the biofilm-forming assay and scanning electron microscopy. In addition, genes encoding known virulence factors such as capsular polysaccharide and flagella were also overexpressed, suggesting an overall enhancement of B. pseudomallei virulence potential when present in human plasma. This ex vivo gene expression profile provides comprehensive information on B. pseudomallei's adaptation when shifted from the environment to the host. The induction of biofilm formation under host conditions may explain the difficulty in treating septic melioidosis.

Степной орёл в Алтае-Саянском регионе – результаты исследований 2019–2023 годов

Степной орёл в Алтае-Саянском регионе – результаты исследований 2019–2023 годов

Fish Effluent as a Source of Water and Nutrients for Sustainable Urban Agriculture

Integrating urban agriculture with aquaculture can reduce the use and cost of water, competition for water, chemical fertilizers, and environmental impact of discharging nutrient-rich agricultural water into fresh and saltwater bodies. In addition, aquaculture in cities can directly benefit human health by providing a local source of lean protein. Despite the potential advantages, few studies have demonstrated the feasibility and production advantages of using aquaculture wastewater to fertigate specialty crops in an urban environment. Therefore, we grew four spring crops (bok choy, tatsoi, radish, turnip) and two fall crops (pole beans, sugar snap peas) in nutrient-rich effluent from fish aquaculture versus well or municipal water to evaluate whether the effluent improved soil fertility and crop production. The fish effluent resulted in changes to the soil through an increase in pH and potassium and to crop production through a 9.1% increase in the number of pole beans (mass of beans also trended toward significance). The soils we used were relatively nutrient-rich prior to the application of the fish effluent, which may be responsible for the limited impact, and differences may be more apparent in acidic and nutrient-poor soils or when fertigation is used over a longer duration.

The universal trophic index: new methodological approach to eutrophication monitoring and control

Anthropogenic eutrophication is one of the consequences of human activities observed from the beginning of urbanization processes and is now a widespread problem around the globe. Mitigation of eutrophication directly corresponds to the achievement of at least three main Sustainable Development Goals. Due to the complexity of eutrophication mechanisms, there are still many issues with managing this process and its consequences, that complicate the achievement of the above-mentioned objectives. So far, there is no universal definition of eutrophication and there is no unified methodological approach to surface water trophic status assessment. In connection with the above, a need arises for the development of scientifically and economically justified methods of reliable trophic state assessment, useful for solving application and engineering tasks. This paper presents a new approach to trophic state assessment based on the innovative universal trophic index (UTI), which can be used for fresh, brackish and saltwater bodies. The proposed UTI index was developed and verified using an extensive database of the Baltic Sea monitoring data for over 100 years. The elaborated method is a reliable tool for the assessment of water trophic status, which also allows for the development of predictive mathematical models as the basis for effective eutrophication management. In addition, the method is simple to use and enables the trophic state assessment at low cost, time and effort. The above-mentioned features make the proposed indicator meet the requirements set for modern ecological indicators and determine the advantage of the proposed methodological approach over other currently used methods.

Temporal change in plant communities and its relationship to soil salinity and microtopography on the Caspian Sea coast

The gradual drying up of saltwater bodies creates habitats that are characterised by changing environmental conditions and might be available only for a subset of plants from the local flora. Using two terrestrial areas with different ages on the Caspian Coast as a chronosequence, we investigated factors including microtopography, ground water level and soil salinity that drive plant community succession after the retreat of the sea. Vegetation of the two key sites appearing after the retreat of the Caspian Sea about 365 and 1412 years ago were compared in terms of both evolutionary and ecological traits of plants. Both edaphic conditions and vegetation differed between the two sites with harsher edaphic conditions and more xerophytes on the elder site. Species that grew only in the ‘early’ site were dispersed across the phylogenetic tree, but their loss on the 'late' site was not random. Species that grew only on the 'late' site were phylogenetically clustered. On the level of microtopography, elevated spots were more densely populated in the ‘early’ site than lowered spots, but on the 'late' site the situation was opposite. The main edaphic factors that drive the difference in vegetation composition between the two sites are likely salinity and moisture. During environmental changes, different plant traits are important to survive and to appear in the community de novo. Microtopography is important for forming plant communities, and its role changes with time.

Using 223Ra and 224Ra to estimate discharges of groundwater and associated nutrients into southeast of Qinghai Lake, in Qinghai–Tibet Plateau

With its important geographical location and status as the largest saltwater body in China, Qinghai Lake plays a vital role in the ecological environment of the northeastern part of the Qinghai-Tibet Plateau. Due to climate change and the subsequent adjustment of Qinghai Lake’s tourism policy, it is necessary to understand groundwater discharges in southeast of Qinghai lake both for ecological protection and risk prevention. This study used radium isotopes 223Ra and 224Ra to trace groundwater discharges and nutrients carried into the lake. The spatial characteristics of Ra isotopes with greater activity in the upper and bottom layers in the lake indicated that they were influenced by inputs of shallow groundwater and diffusion from sediments. The average 224Ra diffusion flux of the sediments in the Lake was 33.54 dpm m−2 d−1. Based on the 224Ra mass balance model, the discharge flux of shallow groundwater in this region was estimated to be 3.49 × 106 ∼ 3.68 × 106m3d−1. The PO43− and SiO2 fluxes carried into the southeastern of the lake by groundwater were 1.78 × 1011 ∼ 1.88 × 1011 mg/y and 2.22 × 1012 ∼ 2.34 × 1012 mg/y, respectively. It is thus essential to monitor shallow groundwater discharge into Qinghai Lake for the protection of the water environment and prevention of potential ecological risks.

Ocean Modeling Analysis and Modeling Based on Deep Learning

The ocean comprises an uninterrupted body of salt water confined within a vast basin on the earth’s surface. The ocean is the largest ecosystem on earth with rich and diverse biological resources. Organisms that reside in salty water are referred to as “marine life.” Plants, animals, and microorganisms including archaea and bacteria are examples of these. The existence of marine life is not only a biological resource but also an economic source. Toys and other industries that imitate marine life have emerged in the market. A different modeling design of marine life has improved with the passage of time and the concept of modeling aesthetics has been incorporated. The identification of marine life images is challenging due to the complexity of the maritime environment, and there are several flaws in marine life models. The rise of deep learning has brought some new ideas for the weaknesses in marine life modeling, and the advantages of convolutional neural networks have contributed to some of the concepts based on deep learning. This research analyses marine modeling by using the benefits of convolutional neural networks, so that people can better understand marine life modeling. The experimental results indicate that the proposed approach has achieved good results in marine life detection, and the modeling effect of ocean modeling analysis based on deep learning is good.

P041 A fishy diagnosis in the immunocompromised patient

Abstract Background/Aims Immunocompromised patients are at risk of developing opportunistic infections. Mycobacterium marinum is an atypical bacterium that is found in bodies of fresh or salt water. Skin infections with Mycobacterium marinum are relatively uncommon and are usually acquired by direct inoculation through broken skin following contact with aquariums or fish. Infection with this bacterium can present with chronic cutaneous lesions, tenosynovitis, septic arthritis, and rarely osteomyelitis. This case emphasises the importance of educating immunocompromised patients with regards to good skincare to prevent inoculation with opportunistic infections. Methods We present the case of a patient with Behcets disease, immunosuppressed with prednisolone, methotrexate and infliximab who presented on a number of occasions with ‘recurrent cellulitis’. Following repeated re-presentations with worsening cutaneous manifestations, specialist review was arranged, and ultimately Mycobacterium marinum was confirmed on tissue culture. Results A 46-year-old nurse, known to the rheumatologist with Behcets disease presented to clinic with new skin lesions affecting her right hand and arm that progressed over a period of 4-months. Initially she noticed intact blisters affecting the fourth finger of her right hand. She subsequently developed painful localised erythema and swelling overlying the third MCPJ which didn't respond to oral antibiotics. She re-attended her local hospital for intravenous flucloxacillin for cellulitis. Septic arthritis was excluded. She did not have any systemic signs of infection and her inflammatory markers remained normal. Oral antibiotics were continued without clinical response and Infliximab and Methotrexate withheld but she remained on 15mg of prednisolone. In the subsequent weeks she developed new cutaneous lesions extending up her right forearm in a spirotrichoid distribution. Further questioning revealed she had recently acquired tropical fish which became unwell and suddenly died. She was reviewed by the dermatologist and tissue biopsy confirmed the diagnosis of Mycobacterium marinum. She was started on ethambutol and azithromycin and within 3-months the cutaneous granulomas resolved. She remained off infliximab and methotrexate until the lesions had resolved but her Behcets flared despite prednisolone, with evidence of synovitis, fatigue and bowel symptoms. Reintroduction of her immunosuppression hasn't resulted in any recurrence of the granulomas. Conclusion Immunocompromised patients are at risk of developing opportunistic infections. This case demonstrates the importance of acquiring a full history including exposure to pets when such infections are considered. We don't routinely council counsel patients with regards to avoidance of water contact or using gloves for persons with open skin lesions. We should be promoting good skin hygiene in all immunocompromised patients. Mycobacterium marium should always be considered in patients with lesions of a sportorichoid nature, most often at the site of an open abrasion on their dominant hand. Systemic signs of infection are rare however immunosuppressed individuals are at higher risk of developing disseminated infection. Disclosure B. Preece: None. S. Edwards: None. C. Jenkins: None. J. Hughes: None.

Solar-pond assisted reverse osmosis-electrodialysis system for seawater desalination and hydroponic fertilizer solution production

ABSTRACT A thermodynamic analysis is performed on a solar-pond assisted reverse osmosis-electrodialysis system to produce freshwater and a hydroponic fertilizer solution for sustainable desalination and waste recovery. The reverse osmosis unit desalinates seawater to produce freshwater and a waste concentrated salt solution rich in many useful ions and minerals. The reverse osmosis unit’s waste stream is sent to an electrodialysis unit that utilizes monovalent membranes to reject magnesium, calcium and sulfate ions. These ions are beneficial for plant growth and the product can be used as a hydroponic fertilizer solution for agricultural purposes. A solar pond is integrated into the system to reduce the power requirements. The solar pond utilizes energy from the sun to store thermal energy in a large body of concentrated salt water with temperatures up to 90°C in the lower convecting zone. This thermal energy is utilized in an organic Rankine cycle with the working fluid R113 to create a self-sustaining desalination and waste treatment system running on solar energy. The system produces about 4.52 kg/s of freshwater and 4.75 kg/s of hydroponic solution. The overall energy and exergy efficiencies of the integrated system are found to be 20.36% and 2.55%, respectively.

Gas-phase ion migration spectrum analysis of the volatile flavors of large yellow croaker oil after different storage periods

The large yellow croaker, a species of fish found in the northwestern Pacific, is favored by consumers because of its prevalence in saltwater bodies, golden yellow abdomen, high calcium content, high protein, high fat content, and a flavor that originates from its lipids and volatile components. Volatile organic compounds significantly affect the aroma of food. In this work, electronic nose and headspace gas chromatography-ion mobility spectrometry were applied to analyze the flavor differences in fish oil durations. Through electronic nose system analysis, sensors W1C, W3S, W6S, and W2S directly affected fish oil flavor, and their flavor components were different. Gas chromatography-ion mobility spectrometry identified 26 volatile components (19 aldehydes, 3 ketones, 2 alcohols, 1 furan, and 1 olefin). (E,E)-2,4-hexadienal (D), (E,E)-2,4-hexadienal (M), 2,4-heptadienal (M), (E)-2-octenal, 2-propanone, 2-heptanone (M), 3-pentanone (D), and 1-octen-3-ol were the key flavor components of the fish oil. In conclusion, the combination of GC-IMS and PCA can identify the differences in flavor changes of large yellow croaker oil during 0–120 days storage. After 60 days storage, the types and signals of 2-propanone, 2-heptanone (M) components increase significantly. When 120 days storage, at this time, (E,E)-2,4-hexadienal (D), (E,E)-2,4-hexadienal (M), 2,4-heptadienal (M), (E)-2-octenal,(E)-2-octenal significantly. It has become the main flavor substance of fish oil. In summary, as the storage period increases, the components increase, and the oxidizing substances will increase, resulting in the deterioration of fish oil.

Lithochemical parameters in equilibrium systems of modern sedimentation in lakes and on the sea shelf

Abstract. The work combines physicochemical and statistical modeling in the description of marine and continental salt water bodies. Sedimentary systems consist of aluminosilicate, carbonate and organogenic source material. Paleoclimatic changes are traditionally considered in the time scale. However, the real fluctuation amplitude of the target natural parameter is usually absent or has insufficient resolution for quantitative paleoclimatic reconstructions. Accessible quantitative analysis of time series is based on mineralogy and geochemistry of bottom sediments. Ahalytical complex includes X-ray phase diagnostics of minerals, SEM and XRF analysis of bulk chemical composition, isotopic dating and counting of annual rhythms. Modern high-resolution techiquem like scanning XRF SR with a measurement step of 1 mm successfully provides the necessary synchronization between analytical data and instrumental seasonal-annual observations. Multiple regression methods are used to calculate the transfer functions for transforming the elemental composition of sediments into time series of the desired target environment. Additional physicochemical equilibrium estimates of sedimentation were calculated, confirming the convergence of the parameters of the selected multisystem (rock + liquid + gas) with environmental conditions. For equilibrium systems, time series of absolute values of the desired parameters, such as temperature, salinity, pH, redox environment, etc., were calibrated with synchronous weather and climate fluctuations. In particular, the reconstruction of marine sediments opened up the prospect of studying the periodicity of ice-free periods in the Arctic Ocean, using quantitative estimates of external conditions from the lithochemistry of bottom sediments.

Fishing Crafts and Gears in Buug, Dumanquillas Bay, Philippines

Dumanquillas Bay is a body of saltwater and the major source of food located in the Southern Mindanao. It has been observed that marine resources and fish catch in the area are declining. This study assumed that fishing practices affect the decline of marine and fish catch in the bay. A study on the documentation of fishing practices in the area is reported here. Key informant interview (KII), focus group discussion, direct observation and document archival were used. Twenty-three (23) fishing practices were observed in the area. Based on R.A. 10654 or the Philippine Fisheries Code, five (5) fishing practices were identified in the bay which are illegal. These are “pahulbot sa lalum”, “pahulbot sa mabaw”, “panubli”, “panguryente” and “troll” that destroys sea grasses, coral reefs and the sea beds. The illegal fishing practices identified poses a threat to the marine resources. It implies weak implementation of fishing policies among the LGU’s and other concerned government institutions and NGA’s. Capacity building, CEPA campaign and committed implementation of the Philippine Fisheries Code (R.A. 10654) should be implemented by the PAMB and stakeholders in the community to manage the remaining coastal marine resources thereby uplifting the socio-economic status of the coastal community and achieve sustainability.

Performance analysis of a solar still using an absorber plate with inclined perforated rectangular fins: Comprehensive study

Solar desalination are one of the most promising ways to solve the problem of water shortage in the regions that are adjacent to the sea or saltwater bodies that have abundant solar radiation and lack of drinking water. The present research aimed to investigate an experimental and theoretical study to improve the thermal performance of conventional double-slope solar stills by using inclined perforated rectangular fins combined with the distilled basin. Two solar stills are manufactured, the first one is a conventional still, and the other is a finned still. Both stills have a (0.75 m2) cross-section area which is the same area of the distillation basin. Stills were examined during February, March, April, and May under the climatic conditions of Baghdad city in Iraq. The theoretical model relied on solving equilibrium equations of heat and mass with the help of the MATLAB program. The results showed that combining the inclined fins with the distillation basin improves productivity by (33.2%) compared to the conventional solar still. The average productivity of water between February and May is about (3.02-3.6 l/day) and (4.13-4.72 l/day) for the conventional and finned solar still, respectively. The theoretical model was validated using experimental results. The theoretical model predicted well the performance and behavior of the solar still with some deviations from the practical results.

Haline Convection within a Fresh-Saline Water Interface in a Stratified Coastal Aquifer Induced by Tide

Sea-tide effects on the fresh-saline water interface (FSI) in a stratified coastal aquifer are examined through laboratory experiments. The physical model, a two-dimensional rectangular flow tank, is filled with layered aquifers and aquitards. The aquifers serve as the main entrances/exits of water to/from the system through significant horizontal flows, creating unstable conditions of heavier saline water above lighter freshwater for short periods of time. Several processes create mixing; this instability results in haline convection, creating downward fingering, stable rising of horizontal saltwater front, and unstable upward fingerings of flushing freshwater. The time lag between the sea tide fluctuations and the emergence of adequate fresh- and saltwater is higher in a stratified system compared to a homogeneous system. Furthermore, longer tide cycles lead to the enlargement of the FSI’s toe horizontal movement range. The combination of tidal forcing with a layering aquifer structure leads to a wider FSI by creating a significant salt- and freshwater mixing inside each layer, vertical flows between the layers, and saltwater bodies at isolated areas. Haline convection within the FSI might be the reason for the wider fresh-saline interfaces that are found in field studies.

Evidence of False Positivity forVibrioSpecies Tested by Gastrointestinal Multiplex PCR Panels, Minnesota, 2016–2018

Syndromic gastrointestinal multiplex polymerase chain reaction (PCR) panels (GMPPs) are used by an increasing number of clinical laboratories to identify enteric pathogens. Vibrio species are included on GMPPs, but because of the low prevalence of vibriosis, performance characteristics for these panels have been difficult to measure. All Vibrio spp. cases identified by GMPPs in Minnesota during 2016-2018 (n = 100) were assessed to identify differences between culture-confirmed cases and those that were PCR-positive only. Overall, 47% of cases had Vibrio species recovered by culture. Two GMPPs were used in Minnesota, Verigene EPT and FilmArray GIP, and the recovery rate of Vibrio spp. was significantly different between these platforms (Verigene EPT 63%, compared with FilmArray GIP 28%). No distinct seasonality was identified among GMPP-positive, culture-negative cases, whereas culture-confirmed case incidence peaked during July and August. Among cases with no other pathogen detected by the GMPP, confirmed cases reported a lower rate of bloody diarrhea (odds ratio [OR], 0.7; P = .004) and were less likely to have a symptom duration >14 days (OR, 0.3; P = .04). Confirmed cases were also more likely to include reports of consuming food items typically associated with Vibrio spp. infection or to have another likely source of infection (eg, international travel or contact with an untreated body of fresh or salt water or marine life; OR, 9.6; P = .001). The combined findings indicate that cases identified by GMPP that did not have culture confirmation were less likely to include symptoms or exposures consistent with vibriosis. These findings emphasize the need for improvements to testing platform specificity and the importance of combining clinical and exposure information when diagnosing an infection. This study underscores the importance of maintaining the ability to culture Vibrio species to aid in accurate diagnoses.