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1
Kim, Choong-Gon, Jae Choi, Sae-Kwang Ku e Chang-Hyun Song. "Immunostimulatory Effects of Korean Mineral-Rich Seawaters on Cyclophosphamide-Induced Immunosuppression in Mice". Marine Drugs 22, n. 6 (21 maggio 2024): 234. http://dx.doi.org/10.3390/md22060234.
Testo completoAbstract (sommario):
Deep seawater (DS), obtained from a depth over 200 m, has health benefits due to its rich nutrients and minerals, and intake of DS has shown diverse immunomodulatory effects in allergies and cancer. Therefore, the immunostimulatory effects of Korean mineral-rich seawaters were examined in a cyclophosphamide (CPA)-induced immunosuppression model. Three samples of Korean seawater, namely DS from the East Sea off the coasts of Pohang (PDS) and Uljin (UDS), and seawater from the West Sea off the coast of Boryeong (BS), were collected. The seawaters were abundant in several minerals (calcium, iron, zinc, selenium, etc.). Mice were orally administered the seawaters for 42 days, followed by CPA-induced immunosuppression. The CPA induction reduced the weight of the spleen and lymph nodes; however, the administration of seawaters increased the weight of the lymphoid organs, accompanied by stimulation of natural killer cells’ activity and NF-kB-mediated cytokine production (IFNγ, TNFα, IL1β, IL6, and IL12). The mouse-derived splenocytes showed lymphoproliferation without cytotoxicity in the seawater groups. Histopathological analysis revealed that the seawaters improved the CPA-induced atrophic changes by promoting lymphoproliferation in the spleen and lymph nodes. These results provide useful information for the use of Korean mineral-rich seawaters, particularly PDS and UDS, as alternative immunostimulants under immunosuppressive conditions.
2
Zhang, Bao Feng, Zhen Hai Liu e Xiao Ma. "A Method of Seawater Sound Velocity Measurement Based on the Transit-Time". Advanced Materials Research 816-817 (settembre 2013): 439–42. http://dx.doi.org/10.4028/www.scientific.net/amr.816-817.439.
Testo completoAbstract (sommario):
In the prospects of maritime development, the accuracy requirements of the marine sonar equipment also getting higher and higher, it is particularly important to measure the sound velocity in seawaters(ultrasound propagation velocity in seawater) in high-precision, in this experiment, basing on the seawater sound velocity variation influencing factors, proposing a method of average measuring the sound velocity of seawater based on STM32 and TDC-GP21 transit-time, The results of the experiment show that this method can be high-precision measurement of the size of the seawater sonic，meet the seawater sound velocity measurement requirements.
3
Živković, Igor, Jan Gačnik, Slaven Jozić, Jože Kotnik, Mladen Šolić e Milena Horvat. "A Simplified Approach to Modeling the Dispersion of Mercury from Precipitation to Surface Waters—The Bay of Kaštela Case Study". Journal of Marine Science and Engineering 10, n. 4 (14 aprile 2022): 539. http://dx.doi.org/10.3390/jmse10040539.
Testo completoAbstract (sommario):
Wet deposition is the main source of mercury (Hg) from the atmosphere to the Earth’s surface. However, the processes that govern the dispersion of deposited Hg in seawater are currently not well understood. To address this issue, total mercury (THg) concentrations in surface seawaters and precipitation were determined on a monthly basis in the Bay of Kaštela (Central Adriatic Sea). Following the assumption that deposited THg is diluted in the seawater bulk due to mixing processes, an exponential decay-like model was developed and the wet deposition of THg was normalized based on periods between precipitation events and seawater sampling. Normalized wet deposition of THg showed significant correlation with the THg gradient in surface seawater after removal of an outlier. To explain the observed outlier, further data normalization included wind data to account for enhanced seawater mixing due to strong winds. Wind-normalized THg deposition of all datapoints showed significant correlation with the THg gradient in surface seawater. The correlation showed that the THg gradient in surface seawater of 0.378 pg L−1 m−1 corresponds to THg wet deposition of 1 ng m−2 after including the influence of wind speed on seawater mixing.
4
Zeynolabedin, Amin, Reza Ghiassi e Moharam Dolatshahi Pirooz. "Investigating island groundwater salinity, using vulnerability index and numerical methods". Water Supply 20, n. 7 (10 agosto 2020): 2804–14. http://dx.doi.org/10.2166/ws.2020.180.
Testo completoAbstract (sommario):
Abstract Seawater intrusion is one of the major issues in Qeshm Island, which is the biggest island of the Persian Gulf. To investigate seawater intrusion in this island, a modified GALDIT index is used to map the vulnerability of the whole region. Considering the vulnerability map, two critical sections which have the highest vulnerability, one in the northeast and the other in the west side of the island, are chosen for detailed investigation. To achieve this goal, two numerical models, MODFLOW and SEAWAT are applied to simulate the groundwater flow and solute transport. The results show that the aquifer is in a dangerous level of threat of vulnerability and 15 km2 of the aquifer is in danger of being salinized. A comparison is made between MT3DMS and SEAWAT results, indicating that SEAWAT simulates seawater intrusion with more accuracy. It seems because of considering salt density in SEAWAT flow equations. The numerical simulation shows that the seawater is intruding on the island at a rapid rate.
5
Ding, Fei, Takao Yamashita e Han Soo Lee. "Atmosphere-Ocean-Groundwater Modeling System for Seawater Intrusion Simulation in Liaodong Bay Coastal Plain, China". Advanced Materials Research 518-523 (maggio 2012): 4155–60. http://dx.doi.org/10.4028/www.scientific.net/amr.518-523.4155.
Testo completoAbstract (sommario):
Precipitation and seawater level are the two important factors to be considered in seawater intrusion simulation. However, these data are lacking in some regions of the world. Thus, limits the study on seawater intrusion. Considering the lack of availability of data on precipitation and seawater level, an atmosphere–ocean-groundwater modeling system was constructed in this paper. In the modeling system, the atmosphere model (MM5) and the ocean model (POM) is used to simulate the precipitation and seawater level, respectively while the SEAWAT model is used for groundwater model simulation. The system is used for seawater intrusion simulation case study in the Liaodong Bay coastal plain. The study shows that the atmosphere–ocean-groundwater modeling system provides a very reasonable result.
6
Hastuti, Yuni Puji, Yuli Siti Fatma, Hardi Pitoyo, Yusli Wardiatno e Siska Tridesianti. "Bacterial and plankton communities in mariculture water sources: a case study in Nampu and Sembukan seawaters, Wonogiri, Indonesia". Natura Croatica 30, n. 2 (31 dicembre 2021): 351–66. http://dx.doi.org/10.20302/nc.2021.30.22.
Testo completoAbstract (sommario):
Seawaters in Indonesia, part of the tropical marine ecosystem, have great microbial and plankton diversity. Seawater is used as a water source for marine aquacultures, such as shrimp, milkfish, lobster, and mud crab. Sustainability of environmental resources for supporting aquaculture activities can be assessed by analyzing the actual conditions of the water source environment, including bacterial and plankton communities. However, the characteristics of bacteria and plankton communities in Indonesian seawaters have not been well documented. In this study, we investigated the bacterial and plankton communities in surface seawater from two coastal areas, i.e. Nampu and Sembukan, Wonogiri regency, Central Java, Indonesia. Bacterial diversity was analyzed using the Illumina-based high throughput sequencing with a primer set targeting the V3-V4 region of the bacterial 16S rRNA gene. Meanwhile, the plankton community (phytoplankton and zooplankton) was calculated and identified using a counting chamber method. Sequencing analysis revealed that the five dominant bacterial phyla in the two seawater samples were similar, consisting of Proteobacteria, Firmicutes, Actinobacteria, Bacteriodetes, and Cyanobacteria. Although the two sites are separated by several kilometres, the distribution of dominant bacterial phyla in both seawater samples is similar. Phytoplankton in Nampu and Sembukan were similarly dominated by Trichodesmium sp., Navicula sp., and Rhabdonema sp. Dominant zooplankton in the two sites were Euterpina, Nauplius, Oithona sp., Oncaea sp., Tigriopus sp., and Gastropoda larvae. The seawater in Nampu and Sembukan is suitable as a water source for aquaculture.
7
Nasser, Abid M., Lital Telser e Yeshayahu Nitzan. "Effect of sunlight on the infectivity ofCryptosporidium parvumin seawater". Canadian Journal of Microbiology 53, n. 9 (settembre 2007): 1101–5. http://dx.doi.org/10.1139/w07-043.
Testo completoAbstract (sommario):
The prevalence of pathogenic microorganisms in seawater can result in waterborne and food borne outbreaks. This study was performed to determine the effect of sunlight and salinity on the die-off of Cryptosporidium parvum . Cryptosporidium parvum oocysts, Escherichia coli , and MS2 coliphage were seeded into tap water and seawater samples and then exposed to sunlight. The die-off of C. parvum in seawater, as measured by infectivity, was greater under sunlight (–3.08 log10) than under dark conditions (–1.31 log10). While, no significant difference was recorded in the die-off of C. parvum, under dark conditions, in tap water as compared to seawater (P < 0.05), indicating that the synergistic effect of salinity and sunlight was responsible for the enhanced die-off in seawater. The die-off of MS2 coliphage and E. coli was greater than that observed for C. parvum under all tested conditions. This indicates that these microorganisms cannot serve as indicators for the presence of C. parvum oocysts in seawaters. The results of the study suggest that C. parvum can persist as infectious oocysts for a long time in seawater and can thus pose a serious hazard by direct and indirect contact with humans.
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Ries, J. B. "Review: geological and experimental evidence for secular variation in seawater Mg/Ca (calcite-aragonite seas) and its effects on marine biological calcification". Biogeosciences 7, n. 9 (21 settembre 2010): 2795–849. http://dx.doi.org/10.5194/bg-7-2795-2010.
Testo completoAbstract (sommario):
Abstract. Synchronized transitions in the polymorph mineralogy of the major reef-building and sediment-producing calcareous marine organisms and abiotic CaCO3 precipitates (ooids, marine cements) throughout Phanerozoic time are believed to have been caused by tectonically induced variations in the Mg/Ca ratio of seawater (molar Mg/Ca>2="aragonite seas", <2="calcite seas"). Here, I assess the geological evidence in support of secular variation in seawater Mg/Ca and its effects on marine calcifiers, and review a series of recent experiments that investigate the effects of seawater Mg/Ca (1.0–5.2) on extant representatives of calcifying taxa that have experienced variations in this ionic ratio of seawater throughout the geologic past. Secular variation in seawater Mg/Ca is supported by synchronized secular variations in (1) the ionic composition of fluid inclusions in primary marine halite, (2) the mineralogies of late stage marine evaporites, abiogenic carbonates, and reef- and sediment-forming marine calcifiers, (3) the Mg/Ca ratios of fossil echinoderms, molluscs, rugose corals, and abiogenic carbonates, (4) global rates of tectonism that drive the exchange of Mg2+ and Ca2+ along zones of ocean crust production, and (5) additional proxies of seawater Mg/Ca including Sr/Mg ratios of abiogenic carbonates, Sr/Ca ratios of biogenic carbonates, and Br concentrations in marine halite. Laboratory experiments have revealed that aragonite-secreting bryopsidalean algae and scleractinian corals and calcite-secreting coccolithophores exhibit higher rates of calcification and growth in experimental seawaters formulated with seawater Mg/Ca ratios that favor their skeletal mineral. These results support the assertion that seawater Mg/Ca played an important role in determining which hypercalcifying marine organisms were the major reef-builders and sediment-producers throughout Earth history. The observation that primary production increased along with calcification within the bryopsidalean and coccolithophorid algae in mineralogically favorable seawater is consistent with the hypothesis that calcification promotes photosynthesis within some species of these algae through the liberation of CO2. The experiments also revealed that aragonite-secreting bryopsidalean algae and scleractinian corals, and bacterial biofilms that secrete a mixture of aragonite and high Mg calcite, began secreting an increased proportion of their calcium carbonate as the calcite polymorph in the lower-Mg/Ca experimental seawaters. Furthermore, the Mg/Ca ratio of calcite secreted by the coccolithophores, coralline red algae, reef-dwelling animals (crustacea, urchins, calcareous tube worms), bacterial biofilms, scleractinian corals, and bryopsidalean algae declined with reductions in seawater Mg/Ca. Notably, Mg fractionation in autotrophic organisms was more strongly influenced by changes in seawater Mg/Ca than in heterotrophic organisms, a probable consequence of autotrophic organisms inducing a less controlled mode of calcification simply through the removal of CO2 via photosynthesis. These results indicate that biomineralogical control can be partially overridden by ambient seawater Mg/Ca and suggest that modern aragonite-secreting organisms may have secreted a mixture of aragonite and low Mg calcite, and that modern high Mg calcite-secreting organisms probably secreted low Mg calcite, in calcite seas of the past. These effects of seawater Mg/Ca on the polymorph mineralogy and calcite Mg/Ca ratio of calcareous skeletons should be accounted for in thermal-chemical reconstructions of seawater that are based upon skeletal Mg/Ca. Lastly, by identifying how marine calcifiers respond to changes in seawater Mg/Ca and absolute Ca2+ concentration, this work should enhance our interpretation of parallel studies investigating the effects of anthropogenic CO2-induced ocean acidification on marine calcification.
9
Ziervogel, K., A. D. Steen e C. Arnosti. "Changes in the spectrum and rates of extracellular enzyme activities in seawater following aggregate formation". Biogeosciences 7, n. 3 (15 marzo 2010): 1007–15. http://dx.doi.org/10.5194/bg-7-1007-2010.
Testo completoAbstract (sommario):
Abstract. Marine snow aggregates are heavily colonized by heterotrophic microorganisms that express high levels of hydrolytic activities, making aggregates hotspots for carbon remineralization in the ocean. To assess how aggregate formation influences the ability of seawater microbial communities to access organic carbon, we compared hydrolysis rates of six polysaccharides in coastal seawater after aggregates had been formed (via incubation on a roller table) with hydrolysis rates in seawater from the same site that had not incubated on a roller table (referred to as whole seawater). Hydrolysis rates in the aggregates themselves were up to three orders of magnitude higher on a volume basis than in whole seawater. The enhancement of enzyme activity in aggregates relative to whole seawater differed by substrate, suggesting that the enhancement was under cellular control, rather than due to factors such as lysis or grazing. A comparison of hydrolysis rates in whole seawater with those in aggregate-free seawater, i.e. the fraction of water from the roller bottles that did not contain aggregates, demonstrated a nuanced microbial response to aggregate formation. Activities of laminarinase and xylanase enzymes in aggregate-free seawater were higher than in whole seawater, while activities of chondroitin, fucoidan, and arabinogalactan hydrolyzing enzymes were lower than in whole seawater. These data suggest that aggregate formation enhanced production of laminarinase and xylanase enzymes, and the enhancement also affected the surrounding seawater. Decreased activities of chondroitin, fucoidan, and arabinoglactan-hydrolyzing enzymes in aggregate-free seawaters relative to whole seawater are likely due to shifts in enzyme production by the aggregate-associated community, coupled with the effects of enzyme degradation. Enhanced activities of laminarin- and xylan-hydrolyzing enzymes in aggregate-free seawater were due at least in part to cell-free enzymes. Measurements of enzyme lifetime using commercial enzymes suggest that hydrolytic cell-free enzymes may be active over timescales of days to weeks. Considering water residence times of up to 10 days in the investigation area (Apalachicola Bay), enzymes released from aggregates may be active over timescales long enough to affect carbon cycling in the Bay as well as in the adjacent Gulf of Mexico. Aggregate formation may thus be an important mechanism shaping the spectrum of enzymes active in the ocean, stimulating production of cell-free enzymes and leading to spatial and temporal decoupling of enzyme activity from the microorganisms that produced them.
10
Ahn, Yu-Hwan. "Development of an Inverse Model from Ocean Reflectance". Marine Technology Society Journal 33, n. 1 (1 gennaio 1999): 69–80. http://dx.doi.org/10.4031/mtsj.33.1.9.
Testo completoAbstract (sommario):
An inverse ocean color model with three components—chlorophyll, suspended sediment and dissolved organic matter—is developed to extract the constituents of seawater from the surface reflectance (400‐700 nm) in oligotrophic, eutrophic and turbid waters. Ocean reflectance obtained from just beneath the sea surface by a spectral radiometer (with 61 bands) is associated with four specific absorption and backscattering coefficients of seawater constituents, including heterotrophic organisms and seawater itself. Although many semi-analytical methods have been used before, this is the first time to apply a purely analytical technique to the inverse model. A known radiative transfer theory was applied to extract the constituents. The model results showed good agreement between the measured values in seawaters and simulated values.
11
Pawlowicz, R., D. G. Wright e F. J. Millero. "The effects of biogeochemical processes on oceanic conductivity/salinity/density relationships and the characterization of real seawater". Ocean Science 7, n. 3 (1 giugno 2011): 363–87. http://dx.doi.org/10.5194/os-7-363-2011.
Testo completoAbstract (sommario):
Abstract. As seawater circulates through the global ocean, its relative composition undergoes small variations. This results in changes to the conductivity/salinity/density relationship, which is currently well-defined only for Standard Seawater obtained from a particular area in the North Atlantic. These changes are investigated here by analysis of laboratory experiments in which salts are added to seawater, by analysis of oceanic observations of density and composition anomalies, and by mathematical investigation using a model relating composition, conductivity, and density of arbitrary seawaters. Mathematical analysis shows that understanding and describing the effect of changes in relative composition on operational estimates of salinity using the Practical Salinity Scale 1978 and on density using an equation of state for Standard Seawater require the use of a number of different salinity variables and a family of haline contraction coefficients. These salinity variables include an absolute Salinity SAsoln, a density salinity SAdens, the reference salinity SR, and an added-mass salinity SAadd. In addition, a new salinity variable S∗ is defined, which represents the preformed salinity of a Standard Seawater component of real seawater to which biogeochemical processes add material. In spite of this complexity, observed correlations between different ocean biogeochemical processes allow the creation of simple formulas that can be used to convert between the different salinity and density measures, allowing for the operational reduction of routine oceanographic observations.
12
Abd-Elhamid, Hany F. "Investigation and control of seawater intrusion in the Eastern Nile Delta aquifer considering climate change". Water Supply 17, n. 2 (3 agosto 2016): 311–23. http://dx.doi.org/10.2166/ws.2016.129.
Testo completoAbstract (sommario):
Seawater intrusion is considered one of the main processes that degrade water quality by raising salinity. Over-pumping and decreasing recharge are considered the main causes of saltwater intrusion. Moreover, climate change and sea-level rise accelerate saltwater intrusion. In this paper SEAWAT code was used to study groundwater flow and seawater intrusion in the Eastern Nile Delta aquifer considering four scenarios of climate change including sea-level rise, increasing abstraction, decreasing recharge and the combination of these scenarios. The results showed that decreasing recharge has a significant effect on seawater intrusion. However, the combinations of these scenarios resulted in harmful intrusion and loss of groundwater. The soil salinity increased, which decreased agricultural production. The control of seawater intrusion and protection of groundwater resources and soil is very important. Different scenarios were implemented to protect the aquifer from seawater intrusion including decreasing abstraction, increasing recharge, abstracting brackish water and the combination of these three scenarios. The abstraction of brackish water gave a higher reduction of seawater intrusion and decreased groundwater table in the aquifer near the shore line, which protected the soil from salinity and increased agricultural production. However, the combination of these three scenarios gave the highest reduction of seawater intrusion.
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Callahan, Kathleen M., Douglas J. Taylor e Mark D. Sobsey. "Comparative survival of hepatitis A virus, poliovirus and indicator viruses in geographically diverse seawaters". Water Science and Technology 31, n. 5-6 (1 marzo 1995): 189–93. http://dx.doi.org/10.2166/wst.1995.0599.
Testo completoAbstract (sommario):
The presence and persistence of enteric viruses in sewage contaminated seawater is an important public health concern for bathing, surfing and shellfishing. In an effort to find suitable indicators of enteric viruses in seawater, we compared the survival of two groups of enteric bacteriophages, F-specific coliphages (FRNA phages) and somatic Salmonella bacteriophages (SS phages), to the survival of two human enteric viruses, hepatitis A virus (HAV) and poliovirus type 1 (PV-1), in coastal seawater from three geographic areas (So. California, Hawaii, and North Carolina) at 20°C. Concentrations of all four viruses decreased over 30 days from their initial titers and there was little difference in the survival of a particular virus among the three seawaters. However, the extent of reduction varied among the four viruses. Survival was greater for the SS phages than for any of the other viruses, with an estimated 4 log10 reduction time of about 10 weeks. FRNA phages and PV-1 were inactivated rapidly, with 4 log10 reductions in ~ 1 week. HAV reductions were intermediate between SS phages and FRNA phages, with 4 log10 reductions in about 4 weeks. The observed differences in virus survival suggest that SS phages are more persistent in seawater than other viruses and hence may be good indicators for enteric viruses in seawater.
14
Wardhani, Maulinna Kusumo, e Dyah Ayu Sulistiyorini. "Assessment of the Quality of Raw Water for Salt Production in Pangarengan, Sampang, East Java". IOP Conference Series: Earth and Environmental Science 1298, n. 1 (1 febbraio 2024): 012026. http://dx.doi.org/10.1088/1755-1315/1298/1/012026.
Testo completoAbstract (sommario):
Abstract Seawater is the primary raw material for the production of sea salt. Seawater quality dramatically affects to salt production. The purpose of this study was to evaluate the seawater’s quality as a raw material for salt production in Pangarengan, Sampang, East Java, Indonesia. The assessment of water quality in this study includes physical and chemical characteristics. The location of this research was in the salt fields that close to settlements with high anthropogenic activity. Sampling points were the seawater inlet (P1), reservoir plot/bozem (P2), and evaporation plot (P3). Assessment of temperature, pH, salinity and water saturation using in-situ measurements. Determination of heavy metal parameters (Mercury, Cadmium, Lead, and Arsenic) using UV spectrometry. The physical characteristics of the highest water temperatures were in evaporated plot (40°C), while the water temperatures in the seawater entrance and reservoir ponds were respectively 33.5 °C and 36 °C. pH, one of the chemicals parameter, at the seawater entrance, reservoir plot, and evaporated plot were 8.2, 7.7, and 9. The salinity of the three points is more than 33 ‰, and the raw water saturation in the evaporated pool is 24° Be. Analysis of heavy metals in this study showed levels below seawater quality standards for consumption purposes.
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Talbayev, Edwige Tamalet. "Seawater". Contemporary French and Francophone Studies 25, n. 2 (15 marzo 2021): 207–17. http://dx.doi.org/10.1080/17409292.2021.1876445.
Testo completo
16
Ries, J. B. "Review: the effects of secular variation in seawater Mg/Ca on marine biocalcification". Biogeosciences Discussions 6, n. 4 (23 luglio 2009): 7325–452. http://dx.doi.org/10.5194/bgd-6-7325-2009.
Testo completoAbstract (sommario):
Abstract. Synchronized transitions in the polymorph mineralogy of the major reef-building and sediment-producing calcareous marine organisms and abiotic CaCO3 precipitates (ooids, marine cements) throughout Phanerozoic time is believed to have been caused by tectonically-induced variations in seawater molar Mg/Ca (>2="aragonite seas"; <2="calcite seas"). Here, I review a series of experiments in which extant calcifying taxa were reared in experimental seawater formulated over the range of mMg/Ca ratios (1.0 to 5.2) that occurred throughout their geologic history. Aragonite-secreting bryopsidalean algae and scleractinian corals and calcite-secreting coccolithophores exhibited higher rates of calcification and growth in the experimental seawaters that favored their skeletal mineral. These results support the assertion that seawater Mg/Ca played an important role in determining which hypercalcifying marine organisms were the major reef-builders and sediment-producers throughout Earth history. The observation that primary production increased along with calcification in mineralogically-favorable seawater is consistent with the hypothesis that calcification promotes photosynthesis within autotrophs through the liberation of CO2. The Mg/Ca ratio of calcite secreted by the coccolithophores, coralline algae and reef-dwelling animals (crustacea, urchins, calcareous tube worms) declined with reductions in seawater Mg/Ca. Calcifying microbial biofilms varied their mineral polymorph with seawater Mg/Ca (mMg/Ca<2=low Mg calc; mMg/Ca>2=arag+high Mg calc), suggesting a nearly abiotic mode of calcification. These results indicate that biomineralogical control can be partially overridden by ambient seawater Mg/Ca and suggests that modern high Mg calcite organisms probably secreted low Mg calcite in calcite seas of the past. Notably, Mg fractionation in autotrophic organisms was more strongly influenced by changes in seawater Mg/Ca, a probable consequence of them inducing a less controlled mode of calcification simply through the removal of CO2 via photosynthesis. This body of work also has implications for thermal-chemical reconstructions of seawater that are based upon skeletal Mg/Ca. And by identifying how marine calcifiers respond to changes in seawater Mg/Ca and absolute Ca2+ concentration, this work should enhance our interpretation of the parallel studies investigating the effects of CO2-induced ocean acidification on marine calcification.
17
Perdikaki, Martha, Efthymios Chrysanthopoulos, Konstantinos Markantonis e Andreas Kallioras. "Groundwater Flow Model Calibration Using Variable Density Modeling for Coastal Aquifer Management". Hydrology 11, n. 4 (22 aprile 2024): 59. http://dx.doi.org/10.3390/hydrology11040059.
Testo completoAbstract (sommario):
The paper investigates the mechanism of seawater intrusion and the performance of free and open-source codes for the simulation of variable density flow problems in coastal aquifers. For this purpose, the research focused on the Marathon Watershed, located in the northeastern tip of Attica, Greece. For the simulation of the groundwater system, MODFLOW, MT3DMS and SEAWAT codes were implemented, while sensitivity analysis and calibration processes were carried out with UCODE. Hydraulic head calibration was performed on the MODFLOW model, and TDS concentration was validated in the SEAWAT model. The calibrated parameters of the MODFLOW model were obtained for the variable density flow simulation with SEAWAT. The MODFLOW and SEAWAT hydraulic head outputs were analyzed and compared to one another. The outcome of this analysis is that SEAWAT produced slightly better results in terms of the hydraulic heads, concluding that parameter transferability can take place between the two models. For the purpose of the seawater intrusion assessment, the use of the SEAWAT code revealed that the aquifer is subjected to passive and passive–active seawater intrusion during wet and dry seasons, respectively. Finally, an irregular shape of a saltwater wedge is developed at a specific area associated with the hydraulic parameters of the aquifer.
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LIU, Qiusheng, Katsuya FUKUDA e Yongwei YANG. "D209 TRANSPORT PROCESS OF CARBON DIOXIDE IN SEAWATER AND SYNTHETIC SEAWATER(Environmental Protection-1)". Proceedings of the International Conference on Power Engineering (ICOPE) 2009.2 (2009): _2–323_—_2–328_. http://dx.doi.org/10.1299/jsmeicope.2009.2._2-323_.
Testo completo
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Pawlowicz, R., D. G. Wright e F. J. Millero. "The effects of biogeochemical processes on oceanic conductivity/salinity/density relationships and the characterization of real seawater". Ocean Science Discussions 7, n. 2 (7 aprile 2010): 773–836. http://dx.doi.org/10.5194/osd-7-773-2010.
Testo completoAbstract (sommario):
Abstract. As seawater circulates through the global ocean, its relative composition undergoes small variations. This results in changes to the conductivity/salinity/density relationship, which is currently well-defined only for Standard Seawater obtained from a particular area in the North Atlantic. These changes are investigated here by analysis of laboratory experiments in which salts are added to seawater, by analysis of oceanic observations of density and composition anomalies, and by mathematical investigation using a model relating composition, conductivity, and density of arbitrary seawaters. Mathematical analysis shows that understanding and describing the effect of changes in relative composition on operational estimates of salinity using the Practical Salinity Scale 1978 and on density using an equation of state for Standard Seawater require the use of a number of different salinity variables and a family of haline contraction coefficients. These salinity variables include an absolute salinity SAsoln, a density salinity SAdens, the reference salinity SR, and an added-mass salinity SAadd. In addition, a new salinity variable S∗ is defined, which represents the preformed salinity of a Standard Seawater component to which biogeochemical processes add material. In spite of this complexity, observed correlations between different ocean biogeochemical processes allow the creation of simple formulas that can be used to convert between the different salinity and density measures, allowing for the operational reduction of routine oceanographic observations.
20
Yusuf, Hamzah, Akhmad Azis, Sugiarto Badaruddin, Andi Muhammad Subhan Saiby, Zulvyah Faisal e Zubair Saing. "Physical modeling of sand columns application in recharge reservoir to prevent seawater intrusion". Water Supply 22, n. 2 (26 ottobre 2021): 2170–78. http://dx.doi.org/10.2166/ws.2021.365.
Testo completoAbstract (sommario):
Abstract This study aims to provide visual evidence by the physical simulation to demonstrate the sand column performance of a recharge reservoir to control seawater encroachment and confirm some previous studies. In this analysis, a two-dimensional sand tank illustrates the sand column's role in overcoming seawater intrusion. Besides using dyes, the sand tank is also fitted with sensors to observe the length of seawater penetration. Furthermore, the simulation using SEAWAT numerical modeling is used as a reference in this analysis. The criteria analyzed were the number of sand columns, the reservoir water level, and the isochlors concentration. The results revealed a reasonably close match between physical and computational modeling. It was also found that the more sand columns and the higher the reservoir water level, resulted in the decrease of seawater penetration length that occurred. Physical and computational modeling findings indicated that the optimal results are derived using three sand columns with an RMSE value of 0.76. The seawater infiltration length decreased to 84.72% relative to sand column-free conditions at a reservoir water level of 15.0 cm.
21
Harmesa, Harmesa, Lestari Lestari e Fitri Budiyanto. "Distribusi Logam Berat Dalam Air Laut Dan Sedimen Di Perairan Cimanuk, Jawa Barat, Indonesia". Oseanologi dan Limnologi di Indonesia 5, n. 1 (9 luglio 2020): 19. http://dx.doi.org/10.14203/oldi.2020.v5i1.310.
Testo completoAbstract (sommario):
<p><strong>Distribution of Heavy Metals in Seawater and Sediments in Cimanuk Estuary, West Java, Indonesia.</strong><strong> </strong>Increasing economic activities in the north coastal of Java have the potential to contribute to anthropogenic contaminants that threaten the water quality of Cimanuk coastal and estuary in Indramayu. Heavy metal which is one of the wastes from these activities has not been studied in detail. The aim of this study was to determine the distribution of Cu, Pb, Cd, Zn, and Ni in seawaters and sediments of the Cimanuk Estuary. Seawater and sediment samples were collected at 18 stations in May 2017. Seawater samples were extracted using the back extraction method while sediment samples were extracted using acids according to USEPA 3050B. Measurement of heavy metals from seawater extracts or sediments was carried out using Flame Absorption Spectrophotometry according to the USEPA 3050B method. The spatial distribution of heavy metals in seawater and sediments is modeled using ArcGIS® version 10.6.1. The results showed that ranges of metals in seawater : 0,0004 – 0,0038 mg/L (Cu), <0,0001 – 0,0044 mg/L (Pb), 0,0002 – 0,0003 mg/L (Cd), 0,0005 – 0,0119 mg/L (Zn), and 0,0020 – 0,0052 mg/L (Ni). While the metal content in sediments are 12,36 – 54,08 mg/kg (Cu), 6,43 – 15,72 mg/kg (Pb), 0,07 – 0,37 mg/kg (Cd), 64,53 – 85,16 mg/kg (Zn), and 19,66 – 62,85 mg/kg (Ni). Spatial distribution models show that heavy metals in seawater and sediments show identical patterns. High level of metals are generally detected at the stations located closed to the mainland, indicating that heavy metals are enrichment from terrestrial anthropogenic activities.</p>
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Abd-Elhamid, Hany, Akbar Javadi, Ismail Abdelaty e Mohsen Sherif. "Simulation of seawater intrusion in the Nile Delta aquifer under the conditions of climate change". Hydrology Research 47, n. 6 (4 gennaio 2016): 1198–210. http://dx.doi.org/10.2166/nh.2016.157.
Testo completoAbstract (sommario):
The problem of seawater intrusion is encountered in almost all coastal aquifers. Because of its higher density, the seawater migrates inland into freshwater aquifers even without any pumping activities. Excessive pumping of groundwater would accelerate seawater intrusion. Climate change and sea level rise represent critical parameters affecting the rate and degree of seawater intrusion. In this paper, a coupled transient finite element model for simulation of fluid flow and solute transport in saturated and unsaturated soils (2D-FEST) is employed to study the seawater intrusion in the Nile Delta aquifer. The results of the current model are compared to results of SEAWAT for model verification. The (2D-FEST) model is used to investigate seawater intrusion considering the impacts of climate change. Three scenarios are studied: (a) rise in sea level, (b) decline of the piezometric head at the land side due to excessive pumping, and (c) combination of sea level rise and decline of the piezometric head. The results show that the rise in the sea level has a significant effect on the position of the transition zone. The third scenario represents the worst case under which the groundwater quality would deteriorate in large areas of the Nile Delta aquifer.
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Mastrocicco, Busico, Colombani, Vigliotti e Ruberti. "Modelling Actual and Future Seawater Intrusion in the Variconi Coastal Wetland (Italy) Due to Climate and Landscape Changes". Water 11, n. 7 (19 luglio 2019): 1502. http://dx.doi.org/10.3390/w11071502.
Testo completoAbstract (sommario):
Coastal freshwater resources are commonly under high risk of being contaminated from seawater. The main processes that affect seawater intrusion are groundwater overexploitation, land use change, and climate change effects. In this context coastal lagoons represent the more sensitive environments prone to seawater intrusion. Numerical modelling is a useful tool to understand and predict seawater intrusion. In this study, a three-dimensional SEAWAT model is employed to simulate the seawater intrusion to coastal aquifers of Variconi Oasis (Italy). The present simulation was divided into a calibration and a validation model, then the model was used to predict the salinization trend up to 2050. Results show the role of the sea in salinizing the beach front, while the retrodunal environment is characterized by transitional environments. Future seawater intrusion scenarios considering only climate data showed no significative differences in respect to the actual situation. The same happens considering also a low sea level rise prediction. On the contrary, the worst scenario (high sea level rise prediction), depicts a quite different situation, with a saline intrusion in the Variconi oasis that will severely affect the fragile transitional ecosystem. This modelling framework can be used to quantify the effects of climate changes in similar coastal environments.
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Xu, Zexuan, Bill X. Hu e Ming Ye. "Numerical modeling and sensitivity analysis of seawater intrusion in a dual-permeability coastal karst aquifer with conduit networks". Hydrology and Earth System Sciences 22, n. 1 (12 gennaio 2018): 221–39. http://dx.doi.org/10.5194/hess-22-221-2018.
Testo completoAbstract (sommario):
Abstract. Long-distance seawater intrusion has been widely observed through the subsurface conduit system in coastal karst aquifers as a source of groundwater contaminant. In this study, seawater intrusion in a dual-permeability karst aquifer with conduit networks is studied by the two-dimensional density-dependent flow and transport SEAWAT model. Local and global sensitivity analyses are used to evaluate the impacts of boundary conditions and hydrological characteristics on modeling seawater intrusion in a karst aquifer, including hydraulic conductivity, effective porosity, specific storage, and dispersivity of the conduit network and of the porous medium. The local sensitivity analysis evaluates the parameters' sensitivities for modeling seawater intrusion, specifically in the Woodville Karst Plain (WKP). A more comprehensive interpretation of parameter sensitivities, including the nonlinear relationship between simulations and parameters, and/or parameter interactions, is addressed in the global sensitivity analysis. The conduit parameters and boundary conditions are important to the simulations in the porous medium because of the dynamical exchanges between the two systems. The sensitivity study indicates that salinity and head simulations in the karst features, such as the conduit system and submarine springs, are critical for understanding seawater intrusion in a coastal karst aquifer. The evaluation of hydraulic conductivity sensitivity in the continuum SEAWAT model may be biased since the conduit flow velocity is not accurately calculated by Darcy's equation as a function of head difference and hydraulic conductivity. In addition, dispersivity is no longer an important parameter in an advection-dominated karst aquifer with a conduit system, compared to the sensitivity results in a porous medium aquifer. In the end, the extents of seawater intrusion are quantitatively evaluated and measured under different scenarios with the variabilities of important parameters identified from sensitivity results, including salinity at the submarine spring with rainfall recharge, sea level rise, and a longer simulation time under an extended low rainfall period.
25
He, Yuntao, Yongjun Liu, Chang Liu e Duan Li. "Analysis of Transmission Depth and Photon Number in Monte Carlo Simulation for Underwater Laser Transmission". Remote Sensing 14, n. 11 (27 maggio 2022): 2565. http://dx.doi.org/10.3390/rs14112565.
Testo completoAbstract (sommario):
The modeling of laser transmission characteristics in complex seawater is fundamental for bathymetric and oceanographic laser detection systems. Because the factors affecting laser transmission in seawater are independent of one another, firstly, in this paper, a Monte Carlo model of laser propagation in seawaters with suspended matter was established to study the influence of suspended matter with specific radius on the underwater laser transmission. Secondly, the influence of transmission depth and the number of photons on the laser extinction coefficients of seawater containing different concentrations of suspended matter were analyzed, respectively. Thirdly, the relationships between maximum transmission depth, the number of initial photons, and the concentrations were built and verified by simulations. Lastly, an experimental platform was set up and experiments were carried out to verify the Monte Carlo model and the relationships. Results show that (1) both the minimum initial photon number and maximum transmission depth depend exponentially on the concentrations of the suspended matter; (2) the extinction coefficients obtained by the Monte Carlo model and those obtained by experiments are consistent. The absolute values of the differences are less than 0.028 m−1, implying that (1) the proposed Monte Carlo model is effective for simulating laser propagation in seawaters with suspended matter; (2) the established relationships between maximum transmission depth, the minimum initial photon number, and the concentrations of suspended matter have better accuracies, which are valuable for the simulations on attenuation of laser transmission in seawater. The method of this paper can also be extended to the study of suspended solids with other radii and improve the simulation accuracy and decrease simulation time consumption.
26
Abd-Elhamid, Hany F., Gamal M. Abdel-Aal, Maha Fahmy, Mohsen Sherif, Martina Zeleňáková e Ismail Abd-Elaty. "Experimental and Numerical Study to Investigate the Impact of Changing the Boundary Water Levels on Saltwater Intrusion in Coastal Aquifers". Water 14, n. 4 (18 febbraio 2022): 631. http://dx.doi.org/10.3390/w14040631.
Testo completoAbstract (sommario):
Experimental and numerical models can be used to investigate saltwater intrusion (SWI) in coastal aquifers. Sea level rise (SLR) and decline of freshwater heads due to climate change are the two key variables that may affect saltwater intrusion. This study aims to give a better understanding of the impact of increasing seawater levels and decreasing freshwater heads due to climate change and increasing abstraction rates due to overpopulation using experimental and numerical models on SWI. The experimental model was conducted using a flow tank and the SEAWAT code was used for the numerical simulation. Different scenarios were examined to assess the effect of seawater rise and landside groundwater level decline. The experimental and numerical studies were conducted on three scenarios: increasing seawater head by 25%, 50% and 75% from the difference between seawater and freshwater heads, decreasing freshwater head by 75%, 50% and 25% from the difference between seawater and freshwater heads, and a combination of these two scenarios. Good agreement was attained between experimental and numerical results. The results showed that increasing the seawater level and decreasing freshwater head increased saltwater intrusion, but the combination of these two scenarios had a severe effect on saltwater intrusion. The numerical model was then applied to a real case study, the Biscayne aquifer, Florida, USA. The results indicated that the Biscayne aquifer is highly vulnerable to SWI under the possible consequences of climate change. A 25 cm seawater rise and 28% reduction in the freshwater flux would cause a loss of 0.833 million m3 of freshwater storage per each kilometer width of the Biscayne aquifer. This study provides a better understanding and a quantitative assessment for the impacts of changing water levels’ boundaries on intrusion of seawater in coastal aquifers.
27
Delly, J., K. Mizuno, T. E. B. Soesilo e M. Gozan. "The Seawater Heavy Metal Content of the Mining Port Close to the Residential Area in the Morowali District". IOP Conference Series: Earth and Environmental Science 940, n. 1 (1 dicembre 2021): 012019. http://dx.doi.org/10.1088/1755-1315/940/1/012019.
Testo completoAbstract (sommario):
Abstract Mining port operations are complex and can cause various forms of pollution. Analysis of seawater pollution from mining ports is required and complicated because of the various types of pollution, sources, effects, and different characteristics. This study examines the content of heavy metals in seawater in residential areas very close to mining ports. The method used sampling in three different places, examining seawater’s heavy metal properties. Secondary data of the quality of seawater was obtained from the results of data monitoring carried out by the company periodically since the port was built as a comparison material from the results of sample inspection. The results of this study indicate that the waters around the settlements contain heavy metals. The composition of Cd was 10%, Pb was125%, Cu was 625%, Ni was 760%, and Zn was 300% above the standard of seawater quality for the Port Area set by the Indonesian government, which did not match the yearly reports (secondary data). On the other hand, community activities also have a minor role as a source of pollution. Therefore, it is essential to do further research with a focus on finding sources of pollution.
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Edward, Helfinalis e Y. Witasari. "The content of polycyclic aromatic hydrocarbon (PAHs) compound of seawater in Mayalibit Bay, West of Papua". IOP Conference Series: Earth and Environmental Science 1119, n. 1 (1 dicembre 2022): 012089. http://dx.doi.org/10.1088/1755-1315/1119/1/012089.
Testo completoAbstract (sommario):
Abstract Polycyclic Aromatic Hydrocarbons (PAHs) are polycyclic aromatic organic compounds that contain several carbon and hydrogen rings, known to be toxic and can be harmful to human life and biota in marine waters. This study aimed to determine the levels of PAHs in seawater in Mayalibit Bay, Papua. Seawater samples were taken using a water sampler at 8 locations in Mayalibit Bay in November 2008. The contaminant content of organic carbon compounds in PAHs was determined by Gas-Chromatography Spectrometry and Mass Spectrometry (GCMS). The results showed a high content of HMW-PAHs and LMW-PAHs and passed the criteria for living status marine organisms by instruction of quality control guidelines by The Environment Ministry of Indonesia. The high molecular weight (HMW-PAHs) type has the highest rate, and LMW-PAH has the widest spread in Mayalibit’s seawaters, higher than Jakarta Bay, Timor Sea and Klabat Bay. The Diagnostic individual ratio analysis shows that the origin of PAHs in Mayalibit’s seawater comes from a pyrogenic source such as: residual petroleum and combustion products of organic matter.
29
Sellegri, Karine, Theresa Barthelmeß, Jonathan Trueblood, Antonia Cristi, Evelyn Freney, Clémence Rose, Neill Barr et al. "Quantified effect of seawater biogeochemistry on the temperature dependence of sea spray aerosol fluxes". Atmospheric Chemistry and Physics 23, n. 20 (16 ottobre 2023): 12949–64. http://dx.doi.org/10.5194/acp-23-12949-2023.
Testo completoAbstract (sommario):
Abstract. Future change in sea surface temperature may influence climate via various air–sea feedbacks and pathways. In this study, we investigate the influence of surface seawater biogeochemical composition on the temperature dependence of number-based sea spray emission fluxes. The dependence of sea spray fluxes was investigated in different water masses (i.e., subantarctic, subtropical and frontal bloom) with contrasting biogeochemical properties across a temperature range from ambient (13–18 ∘C) to 2 ∘C using seawater circulating in a plunging jet sea spray generator. We observed a significant increase in the sea spray total concentration at temperatures below 8 ∘C. Specifically, at 2 ∘C, there was an average 4-fold increase compared to the initial concentration at ambient temperatures. This temperature dependence was more pronounced for smaller-sized sea spray particles (i.e., nucleation and Aitken modes). Moreover, the temperature dependence varied based on the seawater type and its biogeochemical properties. While the sea spray flux at moderate temperatures (8–11 ∘C) was highest in frontal-bloom waters, the effect of low temperature on the sea spray flux was highest in subtropical seawaters. The temperature dependence of the sea spray flux was found to be inversely proportional to the abundance of the cyanobacterium Synechococcus in seawater. This relationship allows for parameterizing the temperature dependence of sea spray emission fluxes based on Synechococcus, which may be utilized in future modeling exercises.
30
Iwahori, Hiroshi. "Seawater Desalination". MEMBRANE 31, n. 1 (2006): 26–27. http://dx.doi.org/10.5360/membrane.31.26.
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31
MIYAGI, MORIO. "Seawater Desalination". Sen'i Gakkaishi 46, n. 7 (1990): P303—P308. http://dx.doi.org/10.2115/fiber.46.7_p303.
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32
Drobyazko, E. V., e A. V. Rastorguev. "Modeling seawater intrusion upon water withdrawal from coastal aquifers". Геоэкология. Инженерная геология. Гидрогеология. Геокриология, n. 1 (21 luglio 2024): 3–12. http://dx.doi.org/10.31857/s0869780924010019.
Testo completoAbstract (sommario):
Seawater intrusions into coastal aquifers have been the object of study by hydrogeologists since long ago. A wide range of methods are used to predict the development of intrusions: analytical, numerical analytical and numerical. The purpose of this paper is to identify and evaluate seawater intrusion using a coastal groundwater intake as an example. The paper considers a coastal groundwater intake, where mineralization, total hardness and chlorides have increased due to intensive exploitation. Seawater intrusion is assumed to be the main reason for the groundwater quality deterioration. To prove the seawater intrusion motion, chemical sampling of water from the intake wells was carried out, which resulted in chlorine-bromine coefficient values indicating the presence of seawater admixture in fresh groundwater. The seawater intrusion was evaluated using numerical-analytical and numerical modelling. The estimation obtained by the analytical element method (GFLOW code) indicates the presence of seawater intrusion at the studied water intake. However, the analytical element method calculations provide the ultimate steady-state estimate of the intrusion development. Also, the method uses the assumption of a sharp freshwater-saltwater boundary. Numerical modelling provides a more realistic assessment. In building the three-dimensional numerical model, special attention was paid to the nature of the connection between the exploited aquifer and the sea. In the onshore part, the Quaternary aquifer is separated from the exploited aquifer by a clay layer with interbedded gravel and sand, but there is no data on the composition of sediments beneath the sea. To clarify their composition, profile numerical models were built in the FEFLOW program with different degrees of connection between the sea and the exploited aquifer. One of the models suggests a direct connection between the sea and groundwater through sand, while the other one is complicated by clay. According to the results of the profile models, the direct connection between the exploited aquifer and the sea was proved, which was taken into account in the construction of the three-dimensional numerical model. On the numerical model in the SEAWAT program, the change in the seawater intrusion position in different periods of water intake operation with different water withdrawal values was obtained, after which the calculation results according to numerical-analytical and numerical models were compared.
33
Zhang, Yu, Yu Hang Gao, Guo Dong Wang, Cheng Yu Li e Ji Ti Zhou. "Seawater Flue Gas Desulfurization and Post-Desulfurization Seawater Recovery". Advanced Materials Research 233-235 (maggio 2011): 662–66. http://dx.doi.org/10.4028/www.scientific.net/amr.233-235.662.
Testo completoAbstract (sommario):
Huge storage tanks of Vinyl chloride monomer (VCM) are often regarded as major hazard installation because VCM is such a kind of flammable, explosive and toxic gas that leakage of liquid VCM would induce fire, explosion and toxic accidents. In this paper, index system of the safety of VCM storage tanks was established by analyzing four main factors including 18 indexes, based on accidents statistic and technology experience. Taking VCM storage tank in a petrochemical plant as a case, AHP-Fuzzy method was applied to achieve single VCM storage tank safety classification. The study could help companies develop preventive measures and emergency planning to reduce casualties and property losses.
34
Tahri, T., S. A. Abdul-Wahab, A. Bettahar, M. Douani, H. Al-Hinai e Y. Al-Mulla. "Desalination of seawater using a humidification-dehumidification seawater greenhouse". Desalination and Water Treatment 12, n. 1-3 (dicembre 2009): 382–88. http://dx.doi.org/10.5004/dwt.2009.970.
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Fukuzumi, Shunichi, Yong-Min Lee e Wonwoo Nam. "Fuel Production from Seawater and Fuel Cells Using Seawater". ChemSusChem 10, n. 22 (24 ottobre 2017): 4264–76. http://dx.doi.org/10.1002/cssc.201701381.
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36
Chang, Yawen, Bill X. Hu e Xue Li. "Modeling Seawater Intrusion to Coastal Aquifers in South Coast of Laizhou Bay, China". E3S Web of Conferences 54 (2018): 00004. http://dx.doi.org/10.1051/e3sconf/20185400004.
Testo completoAbstract (sommario):
In this study, a two-dimensional SEAWAT 2000 model is developed to simulate the seawater intrusion to coastal aquifers and brine water/fresh water interaction in the south of Laizhou Bay, Shandong Province, China and forecast the seawater intrusion and brine water/freshwater interface development in the coming years. The model profile is perpendicular to the coastal line, about 40 km long and 110 m in depth, and consists of two interfaces, freshwater-saline water interface and brine water-saline water-seawater interface. The parameters of aquifers in the SEAWAT-2000 model are calibrated by trial-error method repeatedly to fit the head and salinity measurements. Based on the historical groundwater and brine water exploration and natural precipitation condition, the prediction results indicate that equivalent freshwater head in shallow freshwater-saline water area will decrease year by year and decline 2.0 m in the forecasting period, caused by groundwater over-pumping for irrigating farmlands. The groundwater head in the brine-saline water area will also decrease about 1.8 m in forecasting period. A larger depression cone appears in the brine area, with smaller funnels in other areas. The salinity in the brine area finally drops below 105g/l. In the meanwhile, the salinity increases in other areas, damage fresh groundwater resources.
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Hamouda, Ragaa A., Mayada A. Shehawy, Soad M. Mohy El Din, Fauzeya Mateq Albalwe, Hessa Meteq R. Albalawi e Mervat H. Hussein. "Protective role of Spirulina platensis liquid extract against salinity stress effects on Triticum aestivum L." Green Processing and Synthesis 11, n. 1 (1 gennaio 2022): 648–58. http://dx.doi.org/10.1515/gps-2022-0065.
Testo completoAbstract (sommario):
Abstract Salt stress is one of the most serious factors that influence the plant growth and yield. The extensive use of chemical fertilizers caused an increase in land contamination and hence effects on human health. The use of biofertilizers can solve these problems. In the present work, different concentrations of Spirulina platensis liquid extracts (SLEs; 1%, 2%, and 4%) were used to enhance seeds germination, seedling growth, length of radical, number of leaves, and plant height of T. aestivum L. S. platensis liquid extract (SLE) 2% was chosen to test against salt stress with 10% and 25% seawater in T. aestivum L. watered. The growth parameters such as shoot, root, length, fresh, dry weight, leaf width, number, and area were used to estimate the effects of 2% SLE against salt stress caused by seawater. Also the carbohydrate, protein, phenol, and total antioxidant contents were measured in T. aestivum L. treated with 2% SLE in combination with seawater and watered with different concentrations with seawater alone. The results denote that the best concentration of SLEs was 2%, which promoted the germination growth of T. aestivum L. in comparison to control and other concentrations. SLE (2%) enhanced the carbohydrates, protein, total phenol contents, and antioxidant contents of T. aestivum L., treated with seawaters (SW10% and SW25%) and SLEs in comparison to T. aestivum L. SW 10% and 25% alone. S. platensis liquid extract (SLE) can be used as biofertilizer to enhance the growth and phytochemical contents of T. aestivum L. and to make tolerance of T. aestivum L. against salinity.
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Bonnail, Estefanía, Sebastián Vera e T. Ángel DelValls. "A New Disruptive Technology for Zero-Brine Discharge: Towards a Paradigm Shift". Applied Sciences 13, n. 24 (8 dicembre 2023): 13092. http://dx.doi.org/10.3390/app132413092.
Testo completoAbstract (sommario):
The desalination of aquifers and seawaters is a viable choice to meet primarily domestic and industrial global water requirements. It removes salts from seawater to obtain freshwater with sufficient quality for different purposes, as well as a highly salt-concentrated waste stream known as brine. This residue is usually returned to the ocean, provoking, among other impacts, changes in temperature, salinity and oxygen and overall local aquatic ecosystem stress, as well as social rejection. Desalination in inland aquifers is more complicated because brine disposal is complicated or impossible. The current study presents a new zero-brine discharge technology able to achieve ecological liquid purification through distillation for the separation of the dissolved solids as crystallized salts (Adiabatic Sonic Evaporation and Crystallization, ASE&C). This new technology was used with seawater and three types of brine to test how it would work when coupled with reverse osmosis desalination plants. Analysis of the byproducts after treatment of the seawater and the different brines are presented here. A basic economic approach to calculating potential revenues is also presented. The results of the analyses revealed a complete depuration of water as distilled water, and crystallized solids with highly concentrated commercial salts (with different composition depending on their origin). The estimated economic value of annual revenue (taking into account only seven element recoveries and treatment of a volume of 1000 m3/d) for three types of brines ranged between 1 and 11 million euros, compared to between 3.6 and 9.3 million euros when ASE&C is employed with seawater. The treatment of greater volumes for seawater desalination would increase these numbers significantly. ASE&C supposes a solution coupled (or not) to desalination plants to reduce the ecological impacts associated with brine discharges to zero, obtaining two significant commercial byproducts: (seawater: freshwater and commercial elements Br, Ca, Cs, Cl, NaOH, Mg, N, K, Rb, Na, Sr, Li, U, B, Sr, Ga, etc.; aquifers: a larger list than for saltwater, depending on the nature of the water body). It can solve environmental issues associated with brine discharge, with null CO2 emissions (renewable energy) and profitable (i.e., with no costly pretreatment) technology.
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Wang, Shu Xun, Ying Xia Miao, Jian An Hao, Jing Wang e Yu Shan Zhang. "Analysis on the Technological Advantages of Domestic Seawater". Applied Mechanics and Materials 737 (marzo 2015): 692–95. http://dx.doi.org/10.4028/www.scientific.net/amm.737.692.
Testo completoAbstract (sommario):
The principle of domestic seawater technology is to replace fresh water by seawater. This paper introduces the features and demonstration scale of domestic seawater technology. Considering the successful seawater toilet-flushing in Hong Kong, comparison and economic analysis on the cases of seawater, recycled water and tap water are done. The result shows domestic seawater technology is an economical and efficient water saving technology.
40
Nguyen Dinh, Tung, Sieu Le Nhu, Phuc Nguyen Van, Phu Nguyen Van, Khoa Tran Dinh, Hang Vuong Thi Thu, Nga Nguyen Thi Thanh e Tuyen Le Thi Minh. "Radioactivity of some natural and artificial radionuclides in coastal seawater at Ninh Thuan, Ba Ria - Vung Tau and Ca Mau provinces in 2018". Nuclear Science and Technology 10, n. 2 (9 agosto 2021): 44–51. http://dx.doi.org/10.53747/jnst.v10i2.36.
Testo completoAbstract (sommario):
Radioactivities of some natural (Ra-226, Th-232, U-238, Po-210) and artificial (Cs-137, Sr-90 and Pu-239,240) radionuclides in coastal seawater at monitoring points of Ninh Thuan, Ba Ria - Vung Tau and Ca Mau provinces were analyzed quarterly in the year of 2018. Radioactivities of Ra-226, Th-232, U-238, and Cs-137 had been determined by simultaneous precipitation method and measured on low-level background gamma spectrometer; the radioactivities of Po-210 and Pu- 239,240 had been analyzed by radiochemical separation method and measured on alpha spectrometer; the radioactivity of Sr-90 had been analyzed by radiochemical separation method and measured on low-level background beta counting system. The ranges of radioactivities of Ra-226, Th-232, U-238, Po-210, Cs-137, Sr-90, and Pu-239,240 were 2.71 ÷ 15.91, 3.45 ÷ 35.93, 3.02 ÷ 21.47, 1.51÷ 6.74, 0.88 ÷ 1.68, 1.08 ÷ 1.86 and 0.0026 ÷ 0.0062 mBq/L, with the average values of 6.37, 12.67, 8.34, 3.29, 1.36, 1.46 and 0.0043 mBq/L, respectively. The results shown that the radioactivities of theabove-mentioned radionuclides varied between the seawaters at Ninh Thuan, Ba Ria - Vung Tau and Ca Mau seawater. Additionally, physicochemical parameters in seawater were also surveyed to assess their impact on the fluctuations of the above radionuclides.
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Levy, Miriam, e Abraham J. Susswein. "Separate Effects of a Classical Conditioning Procedure on Respiratory Pumping, Swimming, and Inking in Aplysia fasciata". Learning & Memory 6, n. 1 (1 gennaio 1999): 21–36. http://dx.doi.org/10.1101/lm.6.1.21.
Testo completoAbstract (sommario):
We examined whether swimming and inking, two defensive responses in Aplysia fasciata, are facilitated by a classical conditioning procedure that has been shown to facilitate a third defensive response, respiratory pumping. Training consisted of pairing a head shock (UCS) with a modified seawater (85%, 120%, or pH 7.0 seawater—CSs). Animals were tested by re-exposing them to the same altered seawater 1 hr after the training. For all three altered seawaters, only respiratory pumping is specifically increased by conditioning. Swimming is sensitized by shock, and inking is unaffected by training, indicating that the conditioning procedure is likely to affect a neural site that differentially controls respiratory pumping. Additional observations also indicate that the three defensive responses are differentially regulated. First, different noxious stimuli preferentially elicit different defensive responses. Second, the three defensive responses are differentially affected by shock. Inking is elicited only immediately following shock, whereas swimming and respiratory pumping are facilitated for a period of time following the shock. Third, swimming and respiratory pumping are differentially affected by noxious stimuli that are delivered in open versus closed environments. These data confirm that neural pathways exist that allowAplysia to modulate separately each of the three defensive behaviors that were examined.
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Widianingsih, Widianingsih, Retno Hartati e Hadi Endrawati. "Environmental Characteristic of Phyllophorus sp. (Echinodermata, Holothuroidea, Phyllophoridae) Habitat in the Madura Strait, Indonesia". Jurnal Kelautan Tropis 26, n. 3 (10 gennaio 2023): 419–32. http://dx.doi.org/10.14710/jkt.v26i3.15064.
Testo completoAbstract (sommario):
Information on the environmental characteristics of many sea cucumber habitat is limited, despite these species exhibiting rapid exploitation and may lead to depletion. The present study combined a survey on many seawaters and sediment characteristics of habitat valuable aspidochirote holothurian, Sea Ball Cucumber, Phyllophorus sp. to compare with location with no sea cucumber in Madura Strait, Indonesia. Data from detailed surveys were used to compare both locations with measures of physical and chemical seawater parameters including temperature, salinity, dissolved oxygen, pH, phosphate, nitrate, ammonia, chlorophyll-a, total suspended solids, light transparency, and depth of water. The comparison was also carried out on physical and chemical parameters of surface sediment, i.e. phosphate, nitrate, ammonia, chlorophyll-a, grain size, total organic matter, and carbon-organic content. The data then were analyzed using Mann-Whitney U-Non Parametric Test with SPSS v. 16. The result revealed that there were significant differences between sediment characteristics of Sea Ball Cucumber habitat and no Sea Ball cucumber location, but not for seawater. Seawater parameter value in Madura Strait showed in the range required for its life. This analyzes proved the importance of sediment characteristics for Phyllophorus sp. As benthic deposit feeders, they did not only utilize substrate underneath the body for its habitat but also primarily to supply their natural food.
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Zhang, Cong, Yuyang Xiao, Yujie Fu, Juan Su, Chi Wu, Liping Yu e Qiang Liu. "The Influence of Dissolved Organic Matter to the Seawater Refractive Index Using Optical Refractometer". Journal of Physics: Conference Series 2464, n. 1 (1 marzo 2023): 012026. http://dx.doi.org/10.1088/1742-6596/2464/1/012026.
Testo completoAbstract (sommario):
Abstract Optic refractive index is a good proxy for in situ salinity measurement of seawater according to TEOS-10. Currently, salinity of seawater is estimated by practical salinity (SP), which is calculated by measuring electric conductivity, temperature and pressure using Conductivity-Temperature-Depth (CTD) sensors. However, the electric conductivity method only takes into account the conductive compositions to seawater salinity and ignores the contribution of non-ionic components. However, non-ionic components in seawater affect seawater salinity according to the definition of salinity of seawater, but they could not be measured by conductivity sensor. Optical refractive index is sensitive to all dissolved matters of seawater including ionic and non-ionic components. Here, we take the dissolved organic matter (DOM) extracted from Aoshan Bay seawater as the representative sample to experimentally study the contribution of the non-ionic component to the refractive index of the standard seawater. Seawater refractive indices with different DOM concentrations were measured by a home-made V-shaped groove refractometer. The experimental results show that refractive index of seawater increases linearly with increasing DOM concentration at rate of 1.19 × 10-4/1(g/kg) DOM.
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Suriani, M. J., S. Ramlan e W. B. Wan Nik. "Antifouling Properties of Zinc Nitrate in Seawater". International Journal of Chemical Engineering and Applications 7, n. 5 (ottobre 2016): 314–18. http://dx.doi.org/10.18178/ijcea.2016.7.5.596.
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Makokha, Mary, Akira Kobayashi e Shigeyasu Aoyama. "Numerical Modeling of Seawater Intrusion Management Measures". Journal of Rainwater Catchment Systems 14, n. 1 (2008): 17–24. http://dx.doi.org/10.7132/jrcsa.kj00004978338.
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Guo, Qiaona, Yue Zhao, Zili Hu e Mengjun Li. "Contamination Transport in the Coastal Unconfined Aquifer under the Influences of Seawater Intrusion and Inland Freshwater Recharge—Laboratory Experiments and Numerical Simulations". International Journal of Environmental Research and Public Health 18, n. 2 (18 gennaio 2021): 762. http://dx.doi.org/10.3390/ijerph18020762.
Testo completoAbstract (sommario):
The coupled effect of seawater intrusion and inland freshwater recharge plays an important role in contamination transport in coastal heterogeneous aquifer. In this study, the effects of seawater intrusion and inland recharge on contamination transport were investigated by conducting laboratory experiments and numerical simulations. The laboratory tests were conducted in a sand tank considering two scenarios, namely the conditions of landward and seaward hydraulic gradients. The SEAWAT software was applied for validating the contaminant transport in coastal heterogeneous aquifer. The results indicated that the simulated seawater wedge and contours of the saltwater contaminant matched the observed ones well. The length of the seawater wedge in the scenario of seaward hydraulic gradient was smaller than that in the scenario of landward hydraulic gradient, which reflected that the large quantity of inland recharge have a negative effect on the invasion process of seawater. The plume moved mainly downward in the heterogeneous unconfined aquifer for both scenarios. The pollution plume became concave at the interface between each two layers, which was because the velocity of contaminant plume migration increased gradually from the upper layer to lower layer. The migration direction of the front of the plume was consistent with the direction of hydraulic gradient, which indicated that it was influenced by the water flowing. The maximum area of plume in the scenario of seaward hydraulic gradient was slightly smaller than that in the scenario of landward hydraulic gradient. The maximum area and vertical depth of the pollutant plume were sensitive to the hydraulic conductivity, dispersivity and contamination concentration. This study was of great significance to the controlling of pollution and utilization of freshwater resources in coastal areas.
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Faja, Orooba Meteab, Ali Abd Sharad, Khansa Mohammed Younis, Merriam Ghadhanfar Alwan, Basima Jasim Mohammed e Asmat Ahmad. "Isolation, detection of virulence genes, antibiotic resistance genes, plasmid profile, and molecular typing among Vibrio parahaemolyticus isolated in Malaysian seawater from recreational beaches and fish". July-2019 12, n. 7 (luglio 2019): 1140–49. http://dx.doi.org/10.14202/vetworld.2019.1140-1149.
Testo completoAbstract (sommario):
Background and Aim: Despite the importance of the global emergence of Vibrio parahaemolyticus infections worldwide, there has been scanty information on its occurrence in Malaysian seawaters and fish. This study aimed to determine the occurrence of V. parahaemolyticus isolates using polymerase chain reaction targeted at toxin operon gene, thermostable direct hemolysin (tdh), and tdh-related hemolysin genes and to determine antibiotic resistance pattern, genes, and plasmid profile of V. parahaemolyticus from Malaysian seawaters and fish. Materials and Methods: Samples were collected from four recreational beaches in Malaysia (Port Klang; Bachok; Port Dickson; and Mersing). Thiosulfate-citrate-bile salts-sucrose (TCBS) agar and chromogenic Vibrio agar were used for isolation and identification. Colonies with yellow color on TCBS and green color on chromogenic vibrio (CV) agar were considered to be V. parahaemolyticus and they were subjected to biochemical tests. All V. parahaemolyticus isolates were further subjected to identification using seven specific gene markers. Results: Seventy-three Vibrio isolates were recovered. Only one gene tdh> from seawater isolates of Vibrio has high virulence gene percentage (95.23%). Two genes alkaline serine protease (asp) and (tdh) had high percentage of virulence (83.87% and 80.64%, respectively) from fish. Comparatively, fish isolates have a higher virulence percentage compared to seawater isolates. Only gene streptomycin resistance B (strB) from seawater had 100% of the resistance genes. All isolates were multi-antibiotic resistant. Seventeen antibiotic resistance patterns were observed. The isolates had plasmids of varying sizes ranging from 2.7 kb to 42.4 kb. Dendrogram based on antibiotic resistance patterns of V. parahaemolyticus isolates discriminated the isolates into three clusters. Conclusion: This study demonstrated the occurrence of pathogenic, multi-antibiotic-resistant V. parahaemolyticus strains in Malaysian coastal waters and fish, and this could constitute potential public health risks.
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Zeron, Ivan M., Miguel A. Gonzalez, Edoardo Errani, Carlos Vega e Jose L. F. Abascal. "“In Silico” Seawater". Journal of Chemical Theory and Computation 17, n. 3 (3 febbraio 2021): 1715–25. http://dx.doi.org/10.1021/acs.jctc.1c00072.
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Rajasekhar, D., e N. Manoharan. "Seawater Surveillance Robot". Medico-Legal Update 18, n. 1 (2018): 515. http://dx.doi.org/10.5958/0974-1283.2018.00110.x.
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Stepochkin, Igor Evgenievich. "Automatic Seawater Sampler". Podvodnye issledovaniia i robototehnika, n. 1 (2022): 80–85. http://dx.doi.org/10.37102/1992-4429_2022_39_01_08.
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