Normal Seawater Research Articles

Effects of dissolved binary ionic compounds and different densities of brine on interfacial tension (IFT), wettability alteration, and contact angle in smart water and carbonated smart water injection processes in carbonate oil reservoirs

Interfacial tension and wettability are among factors affecting forces in an oil reservoir. Both of these factors are influenced by chemical mechanisms. For example, the interactions between ions, the rock surface and fatty acids can alter the wettability. Moreover, the competitive effects of salting-out and salting-in on increasing and decreasing the salinity of injected water can lead the water-oil interfacial tension (IFT) to another direction where adding carbon dioxide to the injected water can create factors that change the properties of the oil droplet and consequently change the interfacial tension value. The dissolution of carbon dioxide in smart water (low salinity water) results in a chemical reaction and reduces the density as well, and its diffusion into the oil droplet adjacent to the smart water increases the volume of the droplet and affects its viscosity and other properties. The acid formed by the dissolution of CO2 in the injected water may dissolve some minerals in carbonate rock surface and change the surface properties. The goal in enhanced oil recovery (EOR) process through water injection is to minimize interfacial tension, and moderate rock wettability to exhibit hydrophilic characteristics. Ions in injection water in a certain density cause the interfacial tension to reach relative minimum, and alter oil-wet characteristics of carbonate rocks towards more water-wet characteristics. The effect of CO2 dissolution in injection water, forming carbonated water containing dissolved ions, on these two parameters is obvious and improves them.In this communication, K2SO4, KI, MgSO4, Na2SO4, CaCl2, MgCl2, KCl, and NaCl salts, as binary ionic compounds, were used for producing smart water with concentrations of 1000+1000, 2000+2000, 5000+5000, and 10,000+10,000ppm. Then, the effects of dissolution of these salts on interfacial tension and contact angle between water, oil, and carbonate rock were studied. In addition, CO2 was added to the ionic solution with optimal compositions and densities in terms of minimum interfacial tension under the pressures of 6894.7, 10,342.1, and 13,789.5kPa, and its effects on the latter two parameters were investigated. After that, the effects of ions dissolved in seawater (10 times diluted seawater) on water-oil interfacial tension, wettability of carbonate rock and contact angle under the pressure of 101.4kPa in the absence of CO2, and under the pressures of 6894.7, 10,342.1, and 13,789.5kPa in the presence of CO2 were studied. All tests were conducted at constant temperature of the reservoir (75°C). The minimum interfacial tension was obtained for MgCl2+K2SO4 composition (6.73mN/m), which was lower than the interfacial tension between the initial amount of fresh water and oil (24.145mN/m) by 72%. This reduction reached 83% after carbonating the solution under 2000ppm and 75°C conditions. The minimum contact angle in the aged segment for KCl+MgCl2 composition with concentration of 2000+2000ppm was recorded as 39.80°, which decreased by 49.62% and reached 20.05° by adding CO2 under 13,789.5kPa condition. The interfacial tension between seawater (initial density) and crude oil, under 101.4kPa and 75°C conditions, was obtained as 27.464mN/m. The interfacial tension values under 6894.7, 10,342.1, and 13,789.5kPa conditions were obtained as 25.315mN/m, 25.146mN/m, and 21.464mN/m, respectively. These results reveal a decreasing trend after each dilution stage. In addition to trend, reduction of the initial contact angle in the aged segment in the solution after each dilution step indicates better performance of ionized seawater relative to normal seawater.

Effects of specific wavelength spectra on antioxidant stress and cell damage of the ornamental cleaner shrimp Lysmata amboinensis (De Man, 1888) (Decapoda, Caridea, Lysmatidae) exposed to changing saline environments

AbstractA variety of environmental factors have a major influence on the survival of aquatic organisms, particularly light and salinity, changes in which lead to a range of physiological changes. In the present study, we investigated the levels of stress caused by changes in salinity in the ornamental cleaner shrimp,Lysmata amboinensis, as well as the effect of specific light wavelengths following stress to changes in salinity. We measured the activity of superoxide dismutase (SOD), catalase (CAT), and lipid peroxidation (LPO) in the tissues (gill, hepatopancreas, and muscle) for three days after irradiating shrimp with specific wavelengths of light [red (630 nm), green (520 nm), and blue (455 nm)] at two intensities (0.5 and 1.0 W/m2) following exposure to different saline environments [25 practical salinity units (psu), 30 psu, 35 psu (normal seawater), and 40 psu]. DNA damage was measured using comet assays. Although all of the experimental groups exhibited negative results to changes in salinity, the green and red light groups exhibited positive effects when compared to the other wavelengths and fluorescent light. The effect of wavelength was not influenced by the intensity. In conclusion, the light of green and red wavelengths effectively reduces antioxidant stress and cell damage in cleaner shrimp.

Methods for reconstruction of paleo-seawater pH based on boron isotopes in evaporative depositional sequences: case study using the Cambrian–Lower Ordovician evaporite sequence in the Tarim Block, NW China

Evaluation of paleo-seawater pH is an important aspect to study the paleo-ocean environment. The Paleozoic strata lack foraminiferal shells; therefore, reconstruction of paleo-seawater pH is difficult. In this paper, the Cambrian–Lower Ordovician evaporate sequence present in the Tarim Basin is used as an example to work out methods for reconstruction of paleo-seawater pH for evaporate sequences through study of boron isotopes. Analysis of diagenetically unaltered samples yields δ11B values for normal seawater in an open environment ranging from 7.5 to 12.6‰ (average = 9.4‰) and those of evaporative salt-lake facies ranging from − 4.7 to − 1.8‰ (average = − 3.3‰). With increase in the rate of evaporation of seawater, its pH decreases gradually and the δ11B values of tricoordinated and tetracoordinated compounds decrease synchronously. Using a salt-lake brine with pH 7, δ11B value in sedimentary rock of − 3.3‰ and unfractionated δ11B in tetracoordinated B(OH) 4 − in solution, the average δ11B of the Middle Cambrian–Early Ordovician paleo-seawater came to be 16.2‰. It establishes a workable relationship between δ11B in sedimentary rock and seawater pH. The Middle Cambrian–Early Ordovician normal paleo-seawater pH estimated using the δ11B value of sedimentary rock representing the weakest evaporation intensity is ~ 9.1 that is 0.9 higher than pH of modern seawater. In these calculations, it is assumed that the total dissolved inorganic carbon is unchanged between the Cambrian–Early Ordovician paleo-seawater and modern seawater and the [CO3 2−] content in the paleo-seawater is greater by a factor of 2–3 than that in modern seawater. This increase in [CO3 2−] content is inferred to be one of the main factors for the widespread development of dolomite.

An archaeal biomarker record of paleoenvironmental change across the onset of the Messinian salinity crisis in the absence of evaporites (Piedmont Basin, Italy)

A sudden change from normal marine to extreme paleoenvironmental conditions occurred approximately 6Ma ago in the Mediterranean Basin at the onset of the late Miocene Messinian salinity crisis, one of the most severe ecological crises in Earth history. Strong evaporation and tectonics led to hypersaline conditions, resulting in widespread deposition of evaporites and the apparent annihilation of the marine metazoan biosphere. In contrast to the prominent occurrence of evaporites elsewhere in the Mediterranean, evaporites did not form in the deeper part of some marginal basins at the onset of the crisis. The strata of the Pollenzo section (Piedmont Basin, NW Italy) studied here were deposited in such a paleogeographic setting. Instead of evaporites, a cyclic succession of organic-rich shales and carbonates formed during the early phase of the crisis in the study area. These sediments record a sharp increase in the contents of archaeal molecular fossils that are mostly represented by isoprenoidal dialkyl glycerol diethers (DGDs) and isoprenoidal glycerol dialkyl glycerol tetraethers (GDGTs). Such an expansion of archaeal biomass is best explained by a change of the archaeal communities at the onset of the Messinian salinity crisis. In particular, the appearance of molecular fossils of extremophilic archaea, mostly producing DGDs (archaeol and extended archaeol), suggests the emergence of halophilic archaea. At the same time, lipids of planktonic Thaumarchaeota, especially crenarchaeol, are present across the entire section, suggesting the local persistence of normal marine conditions. In agreement with the sudden appearance of tetrahymanol in the upper part of the section, the persistence of crenarchaeol indicates the establishment of water column stratification after the advent of the Messinian salinity crisis. To further investigate the Piedmont Basin paleoenvironmental conditions, we test the Archaeol Caldarchaeol Ecometric (ACE), a proxy developed for identifying high paleosalinities in waters and possibly in sediments. Despite high ACE values found for the Messinian salinity crisis samples, these values are in contrast with the absence of any lithological evidence for high salinities as well with other biomarker-independent information, indicating low to normal seawater salinities. This apparent contradiction is likely explained by the complexity of the sources of archaeal lipids, especially of caldarchaeol and archaeol, limiting the utility of the ACE for the reconstruction of paleosalinities for Messinian strata.

Early dolomitisation of the Lower-Middle Ordovician cyclic carbonates in northern Tarim Basin, NW China

High-frequency metre-scale cycles are present within the Lower-Middle Ordovician carbonate successions in northern Tarim Basin, NW China. These metre-scale cycles were variably dolomitised from top to bottom. Three types of replacive dolomites were recognised, including dololaminite (very finely to finely crystalline, planar-s to nonplanar-a dolomite; type-1), patterned dolomite (finely crystalline, planar-s dolomite; type-2), and mottled dolomite (finely to medium crystalline, nonplanar-a(s) dolomite; type-3). Petrographic evidence indicate these dolomites were primarily deposited in supratidal to restricted subtidal environments, and formed in near-surface to shallow burial realms. Geochemically, all types of dolomites have similar δ 13C and 87Sr/86Sr ratios comparable to calcite precipitated in equilibrium with the Early-Middle Ordovician seawater. These geochemical attributes indicate that these dolomites were genetically associated and likely formed from connate seawater-derived brines. Of these, type-1 dolomite has δ 18O values (‒4.97‰ to‒4.04‰ VPDB) slightly higher than those of normal seawater dolomite of the Early-Middle Ordovician age. Considering the absence of associated evaporites within type-1 dolomite, its parental fluids were likely represented by slightly evaporated (i.e., mesosaline to penesaline) seawater with salinity below that of gypsum precipitation. More depleted δ 18O values (‒7.74‰ to‒5.20‰ VPDB) of type-2 dolomite and its stratigraphic position below type-1 dolomite indicate the generation of this dolomite from mesosaline to penesaline brines at higher temperatures in near-surface to shallow burial domains. Type-3 dolomite yields the most depleted δ 18O values (–9.30‰ to–7.28‰ VPDB), pointing to that it was most likely formed from coeval seawater-derived brines at highest temperatures in a shallow burial setting. There is a downward decreasing trend in δ 18O values from type-1 through type-2 to type-3 dolomites, and in abundance of dolomites, indicating that the dolomitising fluids probably migrated downward from above and persisted into shallow burial conditions.

Evaluating formation fluid models and calibrations using clumped isotope paleothermometry on Bahamian dolomites

The use of stable oxygen isotopes to understand the mechanisms of dolomite formation has been hampered by the inability to precipitate well-ordered dolomite under normal Earth surface conditions. Several studies have attempted to address this problem, either by precipitating high-temperature ordered dolomites and extrapolating the data to low temperatures or by using more disordered very-high Mg-calcites as a proxy for low temperature dolomites. The result is eight equations that disagree significantly from each other (by as much as ∼3.6‰ in the δ18O value of the precipitating fluid at 25°C), and produce differences which can greatly affect the interpretation of the formation mechanisms for low temperature dolomites. However, by combining the recently developed clumped-isotope paleothermometer, an independent isotopic measurement (∆47) that directly relates to the temperature of formation, to Late Miocene to Pleistocene aged dolomites from the Bahamas with a well-constrained thermal and fluid history, we have attempted to narrow down the viable equations used to interpret the δ18O values of dolomites.The clumped-isotope temperatures measured on the Bahamian dolomites (16–37°C) agrees with the range of temperatures expected in the Bahamas. Pairing these temperatures with geological and mineralogical arguments, we favor the equation suggested by Matthews and Katz (1977), as it is the only one that produces realistic δ18O fluid values across the range of clumped-isotope temperatures. Both the clumped-isotope temperatures and δ18O values of the precipitating fluid show a strong positive covariance that we have interpreted as reflecting the mixing of surface brines that have undergone varying amounts of evaporation and normal seawater. The different mechanisms driving these fluids included formation by normal marine seawater driven by the compensatory flow of the mixing zone, bank wide Kohout convection, and evaporative brine reflux.

Paleoenvironmental conditions of Early Miocene corals, western Makran, Iran

Miocene coral-bearing limestones, distributed in the western Makran Basin, are attributed to Aquitanian and Burdigalian. This investigation is focused on three Early Miocene coral-bearing limestone sections in western Makran. Remarkably, well-preserved scleractinian corals and other components could be very definitive to reconstruct paleoenvironmental conditions. Lithologically, there are some differences between the studied sections. Furthermore, zooxanthellate corals are diverse and abundant in all sections. Based on different components and richness of zooxanthellate corals, it seems that the studied carbonate corals are precipitated in a subtropical condition, between 19 and 20 °C in all sections. In light of the dominancy of corals, the presence of symbiont-bearing larger benthic foraminifera (LBF), lithological features, bioeroding features, and encrusting organisms, the oligotrophic to slightly mesotrophic conditions are considered for Tejek section and the mesotrophic condition had been prevailed in Kermestan and Irer sections. According to light intensity in water column and coral morphotypes, Tejek section is considered to precipitate under euphotic to slightly mesophotic condition, while Kermestan and Irer sections were deposited under mesophotic to euphotic light conditions. In transparent water, photic zones continue to deeper depths, while in less transparent water, these zones are limited to shallower parts. A defined depth in the photic zone may represent euphotic, mesophotic, or oligophotic zone. Based on the water transparency, a taxon in a defined photic zone can occur in various depths. On the basis of trophic-light intensity-depth chart, the estimated depth ranges are 12–85 m for Tejek section and 5–62 m for Kermestan and Irer sections. Water energy as another important factor in environmental condition is acquired from coral morphotypes. Accordingly, Tejek section is precipitated under moderate-high energy and Kermestan and Irer sections are deposited in low to moderate-high energy. The presence of encrusting coralline algae, corals, and other constituents is indicative of different substrates in the studied areas. Corals favorably develop in normal salinity waters. The existence of colonial corals and occurrence of benthic foraminifera with hyaline wall indicate normal seawater conditions.

The Johan Sverdrup Field: Origin of Sulfate-Rich Formation Water and Impact on Scale-Management Strategy

Summary The Johan Sverdrup field will, at maximum, contribute 25% of the total oil production from the Norwegian Continental Shelf (NCS). Plateau production from the fully developed field is estimated at 550,000 to 650,000 BOE/D. Geochemical formation-water interpretation and development of a scale-management strategy have been performed to ensure high well productivity and process regularity of the field. Uncertainty over the composition of formation water made the decision to inject normal seawater or low-sulfate seawater into the reservoir for pressure support a challenge. Water compositions in samples obtained from appraisal wells were unusual for the Norwegian North Sea, being sulfate-rich with negligible barium. This was suspected to be an artifact of drilling-fluid contamination, and corrections were applied to obtain representative estimates. These estimates confirmed that the formation waters had variable salinity (21–48 g/L chloride), and were indeed sulfate-rich (94–746 mg/L) and barium-depleted (< 6 mg/L). The compositions may reflect (a) mixing of formation waters across the field over geological time and/or (b) interactions with the underlying Zechstein group (anhydrite). The focus here is on issue (b) because a detailed evaluation of local/regional aquifer movements in geological time, communication patterns, and flow restrictions is beyond the scope of this paper. Three appraisal wells in the Geitungen Terrace showed barium-rich formation water outside the main reservoir area where no underlying Zechstein group was present. Initially, there were concerns about the scaling risks associated with mixing sulfate- and barium-rich formation waters. However, present geological understanding indicates insignificant aquifer volumes with barium, implying that full-field development and scale strategy do not need to consider barium-rich water. Scale predictions were performed for various strategies: formation-water production, seawater injection, produced-water reinjection, and low-salinity/low-sulfate-water injection. Moderate strontium sulfate (SrSO4) and calcium carbonate (CaCO3) scalings are expected in the production wells. If third-party barium-rich waters are tied in, the topside barium sulfate (BaSO4) scaling risk increases. This work has shown Careful evaluation of formation-water samples/analyses reduces uncertainties associated with water compositions and increases confidence in results and decisions. Underlying geology can influence formation-water compositions. Good-quality water sampling is important for later-phase field development and scale management. The implications for field development are Seawater will be injected into the reservoir for pressure support, with no need for a sulfate-removal plant. Produced-water reinjection will gradually replace seawater to minimize environmental impact. Downhole scale-inhibitor injection has been recommended to protect the upper completion.

Geochemistry of formation waters from the subsalt Tubular Bells Field, offshore Gulf of Mexico: Implications for fluid movement and reservoir continuity

Schlumberger’s modular dynamics tester (MDT) tool was used to test 10 Miocene sands in the Tubular Bells deep water oil field, offshore Gulf of Mexico, United States. Nine sands from true vertical depths of 19,999–26,464 ft (6096–8066 m) were sampled from a single well and another deeper sand (29,075 ft [8,862 m]) from a second well. Using ion and strontium, oxygen, and hydrogen isotopic analysis, the nine MDT water samples were demonstrated to be mostly formation water. The sample in the second well from 29,075 ft (8862 m) is filtrate, based on its oxygen and hydrogen isotopic composition (−4.10‰ and −26.3‰, standard mean ocean water [SMOW]). Insufficient water was recovered for ionic analysis, which made the isotopic analysis even more important to help document the origin of the water in what appears to be a hydrocarbon-charged interval. Using a combination of chemical and isotopic analyses, it is concluded that only two of the sands are possibly in fluid communication or separated by baffles. The other sands are each in separate fluid compartments. The salinity (total dissolved solids) of the formation waters decreases with depth and distance from the salt and ranges from approximately 39,000 to more than 288,000 mg/L. The formation waters have oxygen and hydrogen isotopic compositions ranging from +3.19‰ to +4.52‰ and −16.1‰ to −19.4‰, respectively (SMOW). Bromide–chloride systematics indicate that the formation waters are mixtures of normal seawater and seawater that was evaporated to and probably beyond halite saturation. The evaporite water is sourced from the deeper Jurassic section (Louann Salt) and likely came up along the salt–sediment interface along faults and fractures associated with emplacement of the salt stock and canopy. The formation waters were subsequently enriched in chloride and sodium to varying degrees by dissolution of the diapiric salt. Strontium isotopes are compatible with mixing of highly concentrated (evaporative) Jurassic seawater with relatively low 87Sr/86Sr ratios and much less concentrated (almost seawater salinity) pore water with more radiogenic strontium, the latter derived from silicate reactions during burial diagenesis. Short-chain organic acids are present in high concentrations (>1000 mg/L) along with the organophilic ions boron and iodide. The concentrations of boron, iodide, and organic acids do not correlate with salinity. Boron and iodide show a strong positive relationship with each other and a less strong, but positive, relationship with organic acid concentrations. Boron and iodide are nearly twice as concentrated in waters of oil-bearing sands than in water-bearing sands and appear to be indicators of hydrocarbon proximity. One water-bearing sand has concentrations of boron and iodide as high as those seen in oil-bearing sands, possibly suggesting an updip oil accumulation.

Photosynthesis and calcification in two Halimeda species from Phuket, Thailand

Abstract Calcification rates, as well as rates of photosynthetic inorganic carbon (Ci) uptake and relative electron transport (rETR), were measured by alkalinity titrations and pulse-amplitude-modulated (PAM) fluorometry in a simple experimental set up for Halimeda macroloba and Halimeda borneensis from Tangkhen Bay, Phuket, Thailand. While calcification was saturated at bulk seawater concentrations of ~0.3 and ~0.2 mm CO3 2-, respectively, for the two species, photosynthetic Ci uptake was saturated at ~1.0 and 0.6 mm HCO3 -, respectively. Thus, the normal seawater concentrations of these two Ci forms (0.3 mm CO3 2- and 1.7 mm HCO3 -) were viewed as saturating for both processes. rETR increased towards the end of the incubations as a function of irradiance despite the decrease in Ci uptake. This implies that part of the photosynthetic electron flow was diverted to processes other than CO2 reduction under Ci-limiting conditions, and shows that fluorometry is not a good way to estimate photosynthetic efficiencies under such conditions. Based on the responses to pH and Ci reported here, we estimate that the predicted range of ocean acidification for 2100 will still allow for positive rates of calcification in these two Halimeda species.

REE geochemistry of Early Cambrian phosphorites of Masrana and Kimoi blocks, Uttarakhand, India

Early Cambrian phosphorites of the Masrana block, Uttarakhand, India, show moderate rare earth element (REE) concentrations which are slightly higher than those of the Kimoi block of the same region. Light rare earth element (LREE) concentrations of the phosphorites of both the blocks of the study area are higher than those of heavy rare earth element (HREE) and show normal seawater pattern with decreasing HREE and negative Ce and positive Eu anomalies. Negative Ce anomaly reflects oxidising conditions by getting Ce3+ oxidized to Ce4+ in contrast to positive Eu anomaly which reflects the reducing conditions by getting Eu3+ reduced to Eu2+. These anomalies provide evidence of upwelling and mixing of organic-rich anoxic bottom water and oxic upper seawater before the formation of phosphorite deposits in the basinal site.

녹조류 실염주말의 유주자 방출과 배아생장에 미치는 환경요인의 영향

Effects of environmental factors on the zoospore release and germling growth of Chaetomorpha linum were examined. Zoospore release and germling growth experiments were carried out under a combination of temperatures × irradiances, and a single factor of irradiances, salinities, daylength and nutrients (nitrogen, phosphorus). Zoospore release was maximal under condition of 20℃ × 100 μmol photons m −2 s −1 in a factorial experiment (temperatures × irradiances), at 100 μmol photons m −2 s −1 in irradiance experiment and at 34 psu in salinity conditions. After 24 days in culture, germling growth was maximal at 25℃ × 100 μmol photons m −2 s −1 in temperatures × irradiances and at normal seawater (34 psu) in salinity. Germling growth is faster at higher irradiance under same temperature condition and it increased with increasing daylengths (8−16 h). Chaetomorpha linum grew in wide range of N and P concentrations. The growth of germling was maximal at 50 μM PO₄ 3− and 40 μM NH₄ + . Germling growth was more effective under nitrogen addition than phosphorus addition in culture. In conclusion, optimal environmental conditions for zoospore release were 20℃, 100 μmol photons m −2 s −1 , and 34 psu. In addition, the optimal germling growth was observed at 25℃, 100 μmol photons m −2 s −1 , 34 psu, 16 h, 50 μM (PO₄ 3− ) and 40 μM(NH₄ + ).

Facies analysis and depositional environments of the early Eocene Naredi Formation (Nareda locality), Kutch, Western India

The early Eocene Naredi Formation in the southwestern Kutch represents the initial marine sedimentation in Kutch area during Tertiary period. The 22 m thick succession of Naredi Formation, exposed along cliffs (N 23°34′36.8″, E 68°38′38.1″ and N 23°34′3.1″, E 68°39′7.8″) of the tributary of the Kakdi River in and around Nareda village, is dominantly composed of argillaceous member (also known as gypseous shale member) in the lower part and dominantly biochemically precipitated carbonate member, including newly identified algal and coral reef facies, in the upper part. A total of eight lithofacies have been identified based on sedimentological and micropaleontological attributes; those are alternate green- and brown shale facies, comprising the argillaceous member followed by bioclastic wackestone, Assilina packstone, organically bounded framestone (bioherm), clayey limestone, bioclastic packstone–wackestone alternation and ferruginous coralline limestone in ascending order, which constitute the upper carbonate member. The green as well as brown shale facies are splintery in nature and show horizontal interlamination with gypsum layers. Both these facies contain glauconites with circular to elliptical outline and radial fractures, thus suggesting deposition on a mid- to outer-shelf or restricted lagoonal depositional setting. The overlying horizontally bedded wackestone facies and sparitic packstone facies containing fossil shells of larger benthonic foraminifera, including Assilina spinosa, Assilina and Nummulites burdigalensis with some planktonic forms such as Globigerina and Globorotalia in association to rotalids, ostracods, bivalve and gastropod shells, whose presence depict their deposition in mid- to inner-shelf marine realm under normal seawater salinity. The abundance of peloids, calcispheres and limestone fragments are the major non-biogenic allochems in these facies. Replacement of the ostracods, bivalve and gastropod shells by sparry calcite is also the common feature. The overlying organically bounded algal framestone (bioherm) is characterized by slightly undulatory tabular form in the lower part to concentric undulatory mounds in the upper part showing reef growth at outcrop section whereas framework of curvi-radial concentric growth of carbonate layers under thin section indicates reef formation on shallow marine depositional setting in warm and clear tropical water under normal seawater salinity. The thinly bedded brownish white clayey limestone indicates deposition during deepening of the lagoon. The overlying bioclastic packstone–wackestone alternation facies studded with fragments of algal reef and stromatolitic limestone along with various fossil shells like bivalves, echinoids and gastropods, most of them are micritized, resembles its deposition under back-reef lagoonal environments during storm condition which is overlain by an intertidal coralline limestone deposit showing colonial growth and partial to complete replacement of some of the coral shells by ferruginous mineral along with secondary precipitation of the same within the pores during shallowing of the sea and/or due to late diagenetic changes. Based on shale-carbonate wackestone-packstone-reefal-coralline facies association along with the presence of some key minerals such as glauconite, pyrite, siderite and anhydrite and their genetic link to characteristic depositional milieu, authors have proposed fluctuating depositional environments from lagoonal-barrier ridge to lagoonal-tidal flat for the Naredi Formation.

Conceptual Model of Underground Brine Formation in the Silty Coast of Laizhou Bay, Bohai Sea, China

ABSTRACT Gao, M. S.; Hou, G. H., and Guo, F., 2016. Conceptual model of underground brine formation in the silty coast of Laizhou Bay, Bohai Sea, China. There were three major transgression-regression events since the late Pleistocene in the southern coast of Laizhou Bay, Bohai Sea, China. The three marine facies were correspondingly formed. Large amount of underground brine has been found in the late Pleistocene aquifers. A multi-source fluvial delta sedimentary system where the processes of replenishment, migration, filtration, storage, capping condition act together may be more dominant for the formation of underground brine. The dissolved salinity in the liquid of surface microtopography such as lagoon, paleochannel and tidal creek was originated from marine sediment and influenced partly by normal seawater over the time interval, which ran across the bar during the process of storm surge sometimes, but the water body in the sediment only came from fresh groundwater in the fluvial delta. In order to b...

Submarine Salt Karst Terrains

Karst terrains that develop in bodies of rock salt (taken as mainly of halite, NaCl) are special not only for developing in one of the most soluble of all rocks, but also for developing in one of the weakest rocks. Salt is so weak that many surface-piercing salt diapirs extrude slow fountains of salt that that gravity spread downslope over deserts on land and over sea floors. Salt fountains in the deserts of Iran are usually so dry that they flow at only a few cm/yr but the few rain storms a decade so soak and weaken them that they surge at dm/day for a few days. We illustrate the only case where the rates at which different parts of one of the many tens of subaerial salt karst terrains in Iran flows downslope constrains the rates at which its subaerial salt karst terrains form. Normal seawater is only 10% saturated in NaCl. It should therefore be sufficiently aggressive to erode karst terrains into exposures of salt on the thousands of known submarine salt extrusions that have flowed or are still flowing over the floors of hundreds of submarine basins worldwide. However, we know of no attempt to constrain the processes that form submarine salt karst terrains on any of these of submarine salt extrusions. As on land, many potential submarine karst terrains are cloaked by clastic and pelagic sediments that are often hundreds of m thick. Nevertheless, detailed geophysical and bathymetric surveys have already mapped likely submarine salt karst terrains in at least the Gulf of Mexico, and the Red Sea. New images of these two areas are offered as clear evidence of submarine salt dissolution due to sinking or rising aggressive fluids. We suggest that repeated 3D surveys of distinctive features (± fixed seismic reflectors) of such terrains could measure any downslope salt flow and thus offer an exceptional opportunity to constrain the rates at which submarine salt karst terrains develop. Such rates are of interest to all salt tectonicians and the many earth scientists seeking hydrocarbons associated with salt bodies.

Water acidification activates the innate immune system of Senegalese sole Solea senegalensis

Water acidification activates the innate immune system of Senegalese sole Solea senegalensis

Immune responses of flounder Paralichthys olivaceus vaccinated by immersion of formalin-inactivated Edwardsiella tarda following hyperosmotic treatment.

The aim of the present study was to evaluate the effects of hyperosmotic immersion (HI) vaccination and determine the optimum hyperosmotic salinity for flounder Paralichthys olivaceus by investigating its immune responses following vaccination. Flounder were immersed in 1 of 3 hyperosmotic solutions at 50, 60 and 70‰ salinity, then transferred into 30‰ salinity normal seawater containing formalin-inactivated Edwardsiella tarda for vaccination (3 HI groups), or were immersed in normal seawater as direct immersion (DI group). The results showed that the percentages of surface membrane immunoglobulin-positive (sIg+) cells in peripheral blood leukocytes and spleen leukocytes induced by HI were significantly higher than that with DI (p < 0.05), and the 50‰ salinity group showed the strongest response among the HI groups, which reached peaks at Week 4. ELISA assay showed that the specific serum antibodies gradually increased after vaccination and reached peak at Day 32, and the fish treated with HI showed stronger antibody responses; among the HI groups, a significantly higher specific antibody level was detected in the 50‰ salinity group at Day 32 (p < 0.05). Similarly, the fish treated with HI showed higher specific mucosal antibody levels compared to the DI group, and the mucosal antibody showed a faster response, with peak time arriving 1 wk earlier than for the serum antibody. The relative percent survival (RPS) of flounder treated with HI at 50, 60 and 70‰ salinities were 79, 71 and 57% respectively, while this was 43% in the DI group. These results demonstrated that HI, especially the 50‰ salinity, could efficiently enhance the immune response of flounder and show higher RPS. This has significant value for immunological prevention of edwardsiellosis in flounder.

Erythropoietin Pretreatment Attenuates Seawater Aspiration-Induced Acute Lung Injury in Rats.

Seawater drowning-induced acute lung injury (ALI) is a serious clinical condition characterized by increased alveolar-capillary permeability, excessive inflammatory responses, and refractory hypoxemia. However, current therapeutic options are largely supportive; thus, it is of great interest to search for alternative agents to treat seawater aspiration-induced ALI. Erythropoietin (EPO) is a multifunctional agent with antiinflammatory, antioxidative, and antiapoptotic properties. However, the effects of EPO on seawater aspiration-induced ALI remain unclear. In the present study, male rats were randomly assigned to the naive group, normal saline group, seawater group, or seawater + EPO group. EPO was administered intraperitoneally at 48 and 24h before seawater aspiration. Arterial blood gas analysis was performed with a gas analyzer at baseline, 30min, 1h, 4h, and 24h after seawater aspiration, respectively. Histological scores, computed tomography scan, nuclear factor kappa B p65, inducible nitric oxide synthase, caspase-3, tumor necrosis factor-alpha, interleukin (IL)-1β, IL-6, IL-10, wet-to-dry weight ratio, myeloperoxidase activity, malondialdehyde, and superoxide dismutase in the lung were determined 30min after seawater aspiration. Our results showed that EPO pretreatment alleviated seawater aspiration-induced ALI, as indicated by increased arterial partial oxygen tension and decreased lung histological scores. Furthermore, EPO pretreatment attenuated seawater aspiration-induced increase in the expressions of pulmonary nuclear factor kappa B p65, inducible nitric oxide synthase, caspase-3, tumor necrosis factor-alpha, IL-1β, myeloperoxidase activity, and malondialdehyde when compared with the seawater group. Collectively, our study suggested that EPO pretreatment attenuates seawater aspiration-induced ALI by down-regulation of pulmonary pro-inflammatory cytokines, oxidative stress, and apoptosis.

Osmotic/ionic status of body fluids in the euryhaline cephalopod suggest possible parallel evolution of osmoregulation.

Acclimation from marine to dilute environments constitutes among the dramatic evolutionary transitions in the history of life. Such adaptations have evolved in multiple lineages, but studies of the blood/hemolymph homeostasis mechanisms are limited to those using evolutionarily advanced Deuterostome (chordates) and Ecdysozoa (crustaceans). Here, we examined hemolymph homeostasis in the advanced Lophotrochozoa/mollusc, the other unexplored taxa, and its possible regulation by the vasopressin/oxytocin superfamily peptides known to be implicated in fluid homeostasis in Chordata and Arthropoda. The hemolymph osmotic and ionic status in the euryhaline cephalopod (Octopus ocellatus) following transfer from 30-ppt normal seawater to 20 ppt salinity indicate hyperosmo- and hyperionoregulatory abilities for more than 1 week, as in crustaceans and teleost fish. While ventilation frequency decreased by 1 day, Na+/K+-ATPase activity, which has been generally implicated in ion transport, was induced in two of the eight posterior gills after 1 week. In addition, the octopuses were intravenously injected with 1 or 100 ng/g octopressin or cephalotocin, which are Octopus vasopressin/oxytocin orthologs. After 1 day, octopressin, but not cephalotocin, decreased the hemolymph osmolality and Ca concentrations, as well as urinary Na concentrations. These data provide evidence for possible parallel evolution in hyperionoregulatory mechanisms and coordination by conserved peptides.

Nutritional Status as the Key Modulator of Antioxidant Responses Induced by High Environmental Ammonia and Salinity Stress in European Sea Bass (Dicentrarchus labrax).

Salinity fluctuation is one of the main factors affecting the overall fitness of marine fish. In addition, water borne ammonia may occur simultaneously with salinity stress. Additionally, under such stressful circumstances, fish may encounter food deprivation. The physiological and ion-osmo regulatory adaptive capacities to cope with all these stressors alone or in combination are extensively addressed in fish. To date, studies revealing the modulation of antioxidant potential as compensatory response to multiple stressors are rather lacking. Therefore, the present work evaluated the individual and combined effects of salinity challenge, ammonia toxicity and nutritional status on oxidative stress and antioxidant status in a marine teleost, European sea bass (Dicentrarchus labrax). Fish were acclimated to normal seawater (32 ppt), to brackish water (20 ppt and 10 ppt) and to hypo-saline water (2.5 ppt). Following acclimation to different salinities for two weeks, fish were exposed to high environmental ammonia (HEA, 20 mg/L representing 50% of 96h LC50 value for ammonia) for 12 h, 48 h, 84 h and 180 h, and were either fed (2% body weight) or fasted (unfed for 7 days prior to HEA exposure). Results show that in response to decreasing salinities, oxidative stress indices such as xanthine oxidase activity, levels of hydrogen peroxide (H2O2) and lipid peroxidation (malondialdehyde, MDA) increased in the hepatic tissue of fasted fish but remained unaffected in fed fish. HEA exposure at normal salinity (32 ppt) and at reduced salinities (20 ppt and 10 ppt) increased ammonia accumulation significantly (84 h–180 h) in both feeding regimes which was associated with an increment of H2O2 and MDA contents. Unlike in fasted fish, H2O2 and MDA levels in fed fish were restored to control levels (84 h–180 h); with a concomitant increase in superoxide dismutase (SOD), catalase (CAT), components of the glutathione redox cycle (reduced glutathione, glutathione peroxidase and glutathione reductase), ascorbate peroxidase (APX) activity and reduced ascorbate (ASC) content. On the contrary, fasted fish could not activate many of these protective systems and rely mainly on CAT and ASC dependent pathways as antioxidative sentinels. The present findings exemplify that in fed fish single factors and a combination of HEA exposure and reduced seawater salinities (upto 10 ppt) were insufficient to cause oxidative damage due to the highly competent antioxidant system compared to fasted fish. However, the impact of HEA exposure at a hypo-saline environment (2.5 ppt) also defied antioxidant defence system in fed fish, suggesting this combined factor is beyond the tolerance range for both feeding groups. Overall, our results indicate that the oxidative stress mediated by the experimental conditions were exacerbated during starvation, and also suggest that feed deprivation particularly at reduced seawater salinities can instigate fish more susceptible to ammonia toxicity.