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Tracing groundwater salinization processes in coastal aquifers: a hydrogeochemical and isotopic approach in Na-Cl brackish waters of north-western Sardinia, Italy
G. Mongelli,S. Monni,G. Oggiano,M. Paternoster
Hydrology and Earth System Sciences Discussions , 2013, DOI: 10.5194/hessd-10-1041-2013
Abstract: In the Mediterranean area the demand of good quality water is often threatened by salinization, especially in coastal areas. The salinization is the result of concomitant processes due to both marine water intrusion and rock-water interaction, which in some cases are hardly distinguishable. In northwestern Sardinia, in the Nurra area, salinization due to marine water intrusion has been recently evidenced as consequence of bore hole exploitation. However, the geology of the Nurra records a long history from Paleozoic to Quaternary, resulting in relative structural complexity and in a wide variety of lithologies, including Triassic evaporites. To elucidate the origin of the saline component in the Nurra aquifer, may furnish a useful and more general model for the salinization processes in the Mediterranean area, where the occurrence of evaporitic rocks in coastal aquifers is a common feature. In addition, due to intensive human activities and recent climatic changes, the Nurra has become vulnerable to desertification and, similarly to other Mediterranean islands, surface-water resources can periodically suffer from drastic shortage. With this in mind we report new data, regarding brackish waters of Na-Cl type of the Nurra, including major ions and selected trace elements (B, Br, I and Sr) and isotopic data, including δ18O, δD in water, and δ34S and δ18O in dissolved sulphate. To better depict the origin of the salinity we also analyzed a set of Nurra Triassic evaporites for mineralogical and isotopic composition. The brackish waters have Cl contents up to 2025 mg L 1 and the ratios between dissolved ions and chlorine, with the exception of the Br/Cl ratio, are not those expected on the basis of a simple mixing between rain water and seawater. The δ18O and δD data indicate that most of the waters are within the Regional Meteoric Water Line and the Global Meteoric Water Line supporting the idea that they are meteoric in origin. A relevant consequence of the meteoric origin of the Nurra Na-Cl type water is that the Br/Cl ratio, extensively used to assess the origin of salinity in fresh water, should be used with care also in near coastal carbonate aquifers. Overall, and consistent with the geology and the lithological features of the study area, δ34S and δ18O in dissolved sulphate suggest that water-rock interaction is the responsible for the Nurra Na-Cl brackish water composition. Evaporites dissolution also explain the high chlorine contents since halite has been detected in the gypsum levels. Finally, the Nurra Na-Cl brackish water are undersaturated with
Desalination of Saline and Brackish Waters using Carbon Aerogel Technology
Mohammad Reza Massoudinejad,Akbar Eslami,Hamed Mohammadi,Akbar Eslami
Iranian Journal of Health and Environment , 2012,
Abstract: Normal 0 false false false EN-US X-NONE AR-SA MicrosoftInternetExplorer4 Background and Objectives: The increasing demand for drinking water has led scientists to the use of saline waters, but existing desalinating processes are very expensive. carbon aerogel is a type of organic aerogel that is suitable for desalination owing to its unique porous structure. Low potential of fouling and deposits, very low wastewater production, electrostatic regeneration of aerogels and, in turn, no need to acid consumption, and lower power consumption are some of this technology benefits.Materials and Method: In this experimental- analytical study, the purpose was survey of saline and brackish water desalination using carbon aerogel technology and its comparison with electrolysis.The community studied was synthetic salt water samples, using of TDS and EC indicators. The minimum synthetic samples were 243. In this regard, after polymerization of Resorsinol and Formaldehyde compounds under ambient pressure conditions and then its pyrolysis, we fabricated plates of carbon aerogel.Result: With manufacturing in the pilot-scale, the effect of different parameters, including input salt concentration, current, water flow, distance of between electrodes and pH, on NaCl sorption amount of carbon aerogel electrodes were studied. Generally, adsorption amount increased with increasing of current and NaCl concentration and decreased with increasing of distance electrodes, flow and pH. Results: Fabricating reactor at pilot-scale, we studied the effect of different parameters, including input salt concentration, current, water flow, intra-distance of electrodes, and pH on the NaCl sorption using carbon aerogel electrodes. Generally, adsorption capacity increased with increasing of current and NaCl concentration in the inlet flow, and it decreased with increasing intra-distance of electrodes, flow, and pH.Conclusion: Under the most optimal conditions, our results showed that the NaCl adsorption rate on carbon aerogel electrodes was about 1.43×10-4 M NaCl per g of carbon aerogels indicating its cost-effectiveness. /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-famil
The seasonal distribution, diel vertical distribution and feeding behavior of Paraeuchaeta concinna in the shallow subtropical coastal waters of eastern Hong Kong  [cached]
Wong Chong,Yau Eva Y W,Lie Alle A Y
Aquatic Biosystems , 2012, DOI: 10.1186/2046-9063-8-28
Abstract: Background Predatory copepods of the family Euchaetidae are widely distributed in polar, temperate, subtropical and tropical oceans. Paraeuchaeta concinna is the most abundant Euchaetidae in the subtropical coastal seas of Hong Kong and southern China. However, compared to Euchaetidae species in temperate and polar regions, relatively little information is available on the ecology of P. concinna and other Euchaetidae species in the subtropical oceans. This paper provides information on the seasonal abundance of P. concinna in the coastal seas of eastern Hong Kong. The diel vertical distribution of P. concinna, feeding behavior, and predation impact on mesozooplankton in eastern Hong Kong were also investigated. Results P. concinna is most abundant in winter and spring. Their abundance decreases shoreward, and densities are generally higher in the open waters of eastern Hong Kong than in the inner parts of Mirs Bay and Tolo Harbour. P. concinna exhibits both diel vertical migration and diel feeding rhythms in Mirs Bay. P. concinna females show strong preference for the copepods of the genera Acrocalanus, Paracalanus, and Parvocalanus, and remove ~4% of their standing stocks daily. Conclusions The low abundance of P. concinna during most of the year suggests it is not indigenous to coastal seas of eastern Hong Kong. P. concinna performs diel vertical migration, most likely as a strategy to avoid visual predation. Gut content analysis showed that Acrocalanus, Paracalanus, and Parvocalanus are highly preferred prey of P. concinna. A daily predation impact of ~4% of the standing stocks of Acrocalanus, Paracalanus, and Parvocalanus suggests that P. concinna may play an important role in regulating the populations of these small copepods in Mirs Bay, especially during winter and spring.
Anopheles culicifacies breeding in brackish waters in Sri Lanka and implications for malaria control
Pavilupillai J Jude, Sangaralingam Dharshini, Muthuladchumy Vinobaba, Sinnathamby N Surendran, Ranjan Ramasamy
Malaria Journal , 2010, DOI: 10.1186/1475-2875-9-106
Abstract: Anopheline larvae were collected fortnightly for six months from a brackish water body near Batticaloa town using dippers. Collected larvae were reared in the laboratory and the emerged adults were identified using standard keys. Sibling species status was established based on Y-chromosome morphology for An. culicifacies larvae and morphometric characteristics for An. subpictus larvae and adults. Salinity, dissolved oxygen and pH were determined at the larval collection site.During a six month study covering dry and wet seasons, a total of 935 anopheline larvae were collected from this site that had salinity levels up to 4 parts per thousand at different times. Among the emerged adult mosquitoes, 661 were identified as An. culicifacies s.l. and 58 as An. subpictus s.l. Metaphase karyotyping of male larvae showed the presence of species E of the Culicifacies complex, and adult morphometric analysis the presence of species B of the Subpictus complex. Both species were able to breed in water with salinity levels up to 4 ppt.The study demonstrates the ability of An. culicifacies species E, the major vector of falciparum and vivax malaria in Sri Lanka, to oviposit and breed in brackish water. The sibling species B in the An. subpictus complex, a well-known salt water breeder and a secondary malaria vector in the country, was also detected at the same site. Since global warming and the rise in sea levels will further increase of inland brackish water bodies, the findings have significant implications for the control of malaria in Sri Lanka and elsewhere.Anopheles culicifacies sensu lato (s.l.) is well established as the major vector of both falciparum and vivax malaria in Sri Lanka, while Anopheles subpictus s.l. and certain other species function as secondary vectors [1-4]. Both vector species exist as a species complex in Sri Lanka and elsewhere in Asia [reviewed in [1]]. Only species B and E in the An. culicifacies complex of A-E have been detected in Sri Lanka with sp
Influence of seasonal monsoons on net community production and CO2 in subtropical Hong Kong coastal waters
X.-C. Yuan, K. Yin, W.-J. Cai, A. Y. Ho, J. Xu,P. J. Harrison
Biogeosciences (BG) & Discussions (BGD) , 2011,
Abstract: Data from seven cruises in three different environments including the Pearl River estuary, sewage discharge outfall, and eastern coastal/shelf waters were used to examine the seasonal variations in net community production (NCP) and the biologically active gases O2 and CO2. In the winter dry season, when monsoon-induced downwelling was dominant, NCP was negative ( 84 ± 50 mmol C m 2 d 1) in all three regions. The negative NCP corresponded to O2 influxes of 100 ± 50 mmol O2 m 2 d 1 and CO2 effluxes of 24 ± 10 mmol C m 2 d 1. In the summer wet season, when upwelling brought the deep oceanic waters to the coast due to the southwest monsoonal winds, there was a 2 to 15-fold increase in integrated primary production (IPP) compared to winter. The increase in IPP was likely due to the favorable conditions such as stratification and the nutrient inputs from upwelled waters and the Pearl River estuary. NCP in the mixed layer reached up to 110 ± 48 mmol C m 2 d 1 in the wet season. However, accompanying the high positive NCP, we observed an O2 influx of 100 ± 60 mmol O2 m 2 d 1 and CO2 efflux of 21 ± 15 mmol C m 2 d 1. The contradictory observation of positive NCP and CO2 release and O2 uptake in the mixed layer could be explained by the influence of the southwest monsoon-induced upwelling along with the influence of the Pearl River, as the upwelling brought cold, low dissolved oxygen (DO, 160 ± 30 μM) and high dissolved inorganic carbon (DIC, 1960 ± 100 μatm) water to the surface in the wet season. Hence, the subtropical Hong Kong coastal waters are generally a CO2 source due to the monsoonal influence during both the dry-heterotrophic and wet-autotrophic seasons.
Influence of seasonal monsoons on net primary production and CO2 in subtropical Hong Kong coastal waters  [PDF]
X. C. Yuan,K. D. Yin,W.-J. Cai,A. Y. T. Ho
Biogeosciences Discussions , 2010, DOI: 10.5194/bgd-7-5621-2010
Abstract: Data from seven cruises in three different environments including the Pearl River estuary, sewage discharge outfall and eastern coastal/shelf waters, were used to examine the seasonal variations in net primary production (NPP) and the biologically active gases O2 and CO2. In the winter dry season, when monsoon-induced downwelling was dominant, NPP was low ( 60±50 mmol C m 2 d 1) in all three regions. The negative NPP corresponded to low O2 influxes ( 100±50 mmol O2 m 2 d 1) and CO2 effluxes (24±10 mmol C m 2 d 1). In the summer wet season, when upwelling brought the bottom oceanic waters to the nearshore due to the southwest monsoonal wind, there was a 2 to 15-fold increase in integrated primary production (IPP) compared to winter. The increase in IPP was likely due to the favorable conditions such as stratification and the nutrient inputs from upwelled waters and the Pearl River estuary. NPP reached up to 240±100 mmol C m 2 d 1 in the wet season. However, accompanying the high positive NPP, we observed an influx of O2 ( 100±60 mmol O2 m 2 d 1) and efflux of CO2 (25±15 mmol C m 2 d 1). The high positive NPP corresponding to a CO2 source and O2 sink could be explained by the influence of the southwest monsoon-induced upwelling, as the upwelling brought cold, low DO (160±30 μM) and high DIC (1960±100 μatm) water to the surface in the wet season. Hence, the subtropical Hong Kong coastal waters are generally a CO2 source due to the monsoonal influence in both the dry and wet seasons.
Cyanobacterial hepatotoxins, microcystins and nodularins, in fresh and brackish waters of the Pomeranian Province, northern Poland
Hanna Mazur-Marzec, Lisa Spoof, Justyna Kobos, Marcin Pliński, Jussi Meriluoto
Oceanological and Hydrobiological Studies , 2008, DOI: 10.2478/v10009-008-0014-0
Abstract: Microcystins (MCs) and structurally related nodularins (NODs) are hepatotoxic cyclic peptides produced by bloom-forming cyanobacteria. These toxins have been implicated in the deaths of wild and domestic animals as well as in incidents of human illness. Cyanobacterial toxins occurring in the fresh and brackish waters of the Pomeranian Province, northern Poland were characterized in this study. Water samples collected from seven lakes in August and September 2005 were analysed by high performance liquid chromatography (HPLC), enzyme linked immunosorbent assay (ELISA) and protein phosphatase inhibition assay (PPIA). Cyanobacterial toxins present in field samples and in an isolated strain of Planktothrix agardhii were also characterized by liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). In most of the fresh water samples MC-LR, MC-RR and MC-YR dominated. In the lakes where P. agardhii was most abundant demethylated microcystin variants tentatively identified as [D-Asp3]MC-LR, [D-Asp3]MC-YR and [D-Asp3]MC-RR, were found. Total concentrations of the toxins measured by HPLC ranged from 0.1 μg 1-1 to 305.4 μg 1-1. Nodularia spumigena bloom samples were collected from brackish waters of the Gulf of Gdańsk, southern Baltic, and LC-ISP-MS/MS of extract from these revealed the presence of two geometrical isomers of linear nodularin and nodularin variant with aspartic acid methyl ester [MeAsp1(OMe)]NOD.
LIPID PRODUCING MICROALGAE FROM SEVERAL ECOSYSTEMS IN WEST AND CENTRAL JAVA, INDONESIA  [cached]
DWI ANDREAS SANTOSA,SULASTRI,SARJITO
BIOTROPIA : the Southeast Asian Journal of Tropical Biology , 2010,
Abstract: This study is aimed to get lipid producing microalgae as feedstock for biofuel production. The microalgae were isolated from 355 collected water samples which represented many distinct ecosystems such as paddy fields, rivers, agricultural dams, ponds, swampy areas and unique ecosystem of volcano and mud-volcano craters in West- and Central Java, Indonesia. A total of 267 strains of microalgae were isolated from the samples of which 221 strains of them have capability to produce lipid. There were four promising strains that produce lipid between 14.7 – 45.7 percent dry weight in optimal condition that were identified as Chlamydomonas sp. KO-7267 and PK-7195, Chlorella sp. KS-7300 and Desmodesmus sp. BK-7291.
Distribution of picophytoplankton communities from brackish to hypersaline waters in a South Australian coastal lagoon
Mathilde Schapira, Marie-Jeanne Buscot, Thomas Pollet, Sophie C Leterme, Laurent Seuront
Aquatic Biosystems , 2010, DOI: 10.1186/1746-1448-6-2
Abstract: Highest picophytoplankton abundances were recorded under salinity conditions ranging between 8.0% and 11.0% (1.3 × 106 to 1.4 × 106 cells ml-1). Two populations of picocyanobacteria (likely Synechococcus and Prochlorococcus) and 5 distinct populations of pico-eukaryotes were identified along the salinity gradient. The picophytoplankton cytometric-richness decreased with salinity and the most cytometrically diversified community (4 to 7 populations) was observed in the brackish-marine part of the lagoon (i.e. salinity below 3.5%). One population of pico-eukaryote dominated the community throughout the salinity gradient and was responsible for the bloom observed between 8.0% and 11.0%. Finally only this halotolerant population and Prochlorococcus-like picocyanobacteria were identified in hypersaline waters (i.e. above 14.0%). Salinity was identified as the main factor structuring the distribution of picophytoplankton along the lagoon. However, nutritive conditions, viral lysis and microzooplankton grazing are also suggested as potentially important players in controlling the abundance and diversity of picophytoplankton along the lagoon.The complex patterns described here represent the first observation of picophytoplankton dynamics along a continuous gradient where salinity increases from 1.8% to 15.5%. This result provides new insight into the distribution of pico-autotrophic organisms along strong salinity gradients and allows for a better understanding of the overall pelagic functioning in saline systems which is critical for the management of these precious and climatically-stress ecosystems.The ubiquitous distribution of picophytoplankton and their importance in terms of biomass and production, make them a critical component of food web and carbon cycling in marine systems [1-3]. In particular the partitioning between picophytoplankton and larger cells reflects the source and cycling of nutrients [4] and influences the pathway of matter transfer to higher trophic
Hydrochemical Facies, Groundwater Pattern in 'Red Beds and Basaltic aquifers', origin of Brackish waters and salt encrustation, Khanapur Plateau, Western Ghats, Maharashtra, India.  [PDF]
Siddig M.E,O.A.O.Al-Imam,Hussein A.H.
International Journal of Engineering Sciences & Research Technology , 2013,
Abstract: An integrated Hydrochemical, geochemistry and mineralogy of the salts encrustation on the 'red beds' on the Khanapur plateau, along the eastern side of the Western Ghats (Hills) of India region of the Indian peninsula. This area receives low precipitation (638 mm/year) as compared to the western side (4000 to 6000mm/year). Over a greater of the Deccan Volcanic Province of India, the basaltic aquifers contain fresh water with TDS<1000ppm. However, brackish waters (TDS>1000ppm and <10.000ppm) have been recorded in the alluviated aquifers in the region. The present study deals for the first time with an occurrence of brackish waters in the 'red beds' area on the Khanapur Plateau. The data collected for groundwater samples and salt encrustation, suggesting the origin of salinity imposed to the groundwater system in the area. It is evident that the waters are saline during the pre-monsoon period. The semi-arid climate conditions prevailing in the area during the Quaternary period and chemistry and mineralogy of the 'red beds', might have played an important role in imparting salinity to both soil and groundwaters. There are significant variations in the chemistry/quality of groundwaters in different seasons and aquifers. The groundwaters show changes in their chemical characteristics during monsoon season and waters from the shallow basaltic and 'red beds' aquifers exhibit shift in their Hydrochemical facies from Cl+SO4, HCO3 to HCO3, Cl+SO4. The post-monsoon season shows the dominance of groundwaters with Cl+SO4, HCO3 anion Hydrochemical facies with shift in the cation Hydrochemical facies from Na+K, Ca+Mg to Ca+Mg, Na+K. The calculated SAR values indicated that the water is saline and do not suitable for irrigation. The salt samples subjected to chemical and mineralogical analysis to understand their origin and genesis. IR data shows the dominant of the carbonate minerals as, magnesite, calcite and dolomite associated with clay as montmorillonite, illite, huntite, kaolinite, nontronite and other iron oxides; hematite, siderite, , goethite, with quartz and gypsum.
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