Saline Water Environment Research Articles

Biodynamics of Silver Nanoparticles in an Estuarine Oyster Revealed by 110mAgNP Tracing.

The prevalence of silver nanoparticles (AgNPs) requires a comprehensive understanding of their biological impacts especially in marine and estuarine environments. Nevertheless, the background Ag concentration in organisms may impede the accuracy of Ag detection if the net accumulated Ag is low over a short exposure period. Here, a radio-synthesizing method was employed to trace the behavior of AgNPs with two sizes (15 and 60 nm) and two coatings (humic acid and citrate) in an estuarine oyster Crassostrea hongkongensis. This method was sensitive to detect the bioaccumulation and depuration of AgNPs in the oysters over a short period of exposure, which was necessary given the significant changes of particle aggregation in saline water environments. Through radioactive AgNP tracing and biokinetic modeling, we for the first time demonstrated the differential uptake mechanisms of different-sized AgNPs in oysters. Specifically, the ingestion of particles dominated the uptake of 60 nm AgNPs, whereas dermal uptake and ingestion contributed equally to 15 nm AgNPs. Surface coating (humic acid vs citrate) did not significantly affect the uptake of AgNPs by the oysters. The depuration of AgNPs from the oysters was relatively faster than that for the Ag ion. The digestive gland was the key detoxification organ of AgNPs with the greatest loss of Ag by the end of depuration. The findings of this study provide fundamental knowledge for nano-specific risk assessment in marine and estuarine environments.

Organic Geochemical Characteristics of the Upper Cretaceous Qingshankou Formation Oil Shales in the Fuyu Oilfield, Songliao Basin, China: Implications for Oil-Generation Potential and Depositional Environment

The Cretaceous Era has always been a focus of geologic and palaeoenvironmental studies. Previous researchers believed that the impact of the global carbon cycle represents significant short-term global biogeochemical fluctuations, leading to the formation of a large number of organic rich sediments in the marine environment. During the Turonian, a large number of organic-rich oil shales were deposited in the lakes of the Songliao Basin in the Qingshankou Formation. How the depositional environment affected the formation of oil shales in continental lakes and the characteristics of these oil shales remain controversial. In this paper, through sampling of Qingshankou Formation strata, various testing methods are used to provide a variety of new data to study the characteristics of oil shales and palaeoenvironment evolution history in the Songliao Basin. The research of the sediments in the Qingshankou Formation in the Fuyu oilfield, Songliao Basin, via result analysis revealed that the oil shales possess an excellent oil-generation potential with moderate-high total organic carbon (TOC) levels (0.58–9.43%), high hydrogen index (HI) values (265–959 mg hydrocarbons (HC)/g TOC), high extractable organic matter (EOM) levels (2.50–6.96 mg/g TOC) and high hydrocarbon fractions (48–89%). The sources of the organic matter were mainly zooplankton, red algae and higher plants (including marine organisms). The aqueous palaeoenvironment of the Qingshankou Formation was a saline water environment with a high sulfate concentration, which promoted an increase in nutrients and stratification of the water density in the lake basin. Oxygen consumption in the bottom water layer promoted the accumulation and burial of high-abundance organic matter, thus forming the high-quality oil shales in the Qingshankou Formation. The global carbon cycle, warm-humid palaeoclimate, dynamic local biogeochemical cycling and relative passive tectonism were the most likely reasons for the TOC increase and negative δ13Corg deviation.

Potential KPC-2 carbapenemase reservoir of environmental Aeromonas hydrophila and Aeromonas caviae isolates from the effluent of an urban wastewater treatment plant in Japan.

Summary Aeromonas hydrophila and Aeromonas caviae adapt to saline water environments and are the most predominant Aeromonas species isolated from estuaries. Here, we isolated antimicrobial‐resistant (AMR) Aeromonas strains (A. hydrophila GSH8‐2 and A. caviae GSH8M‐1) carrying the carabapenemase bla KPC‐2 gene from a wastewater treatment plant (WWTP) effluent in Tokyo Bay (Japan) and determined their complete genome sequences. GSH8‐2 and GSH8M‐1 were classified as newly assigned sequence types ST558 and ST13, suggesting no supportive evidence of clonal dissemination. The strains appear to have acquired bla KPC‐2‐positive IncP‐6‐relative plasmids (pGSH8‐2 and pGSH8M‐1‐2) that share a common backbone with plasmids in Aeromonas sp. ASNIH3 isolated from hospital wastewater in the United States, A. hydrophila WCHAH045096 isolated from sewage in China, other clinical isolates (Klebsiella, Enterobacter and Escherichia coli), and wastewater isolates (Citrobacter, Pseudomonas and other Aeromonas spp.). In addition to bla KPC‐2, pGSH8M‐1‐2 carries an IS26‐mediated composite transposon including a macrolide resistance gene, mph(A). Although Aeromonas species are opportunistic pathogens, they could serve as potential environmental reservoir bacteria for carbapenemase and AMR genes. AMR monitoring from WWTP effluents will contribute to the detection of ongoing AMR dissemination in the environment and might provide an early warning of potential dissemination in clinical settings and communities.

Lake evolution and its influence on the formation of oil shales in the Middle Jurassic Shimengou Formation in the Tuanyushan area, Qaidam Basin, NW China

The non-marine Qaidam Basin is a petroliferous basin in northwest China. The Tuanyushan area is located in the Saishiteng Depression in the northern Qaidam Basin. Coal and oil shales are widely developed in the Middle Jurassic Dameigou and Shimengou formations in this area where the sedimentary sequence and controls on coal accumulation have already been well documented. However, the geochemical characteristics of lacustrine fine-grained sediments, including lacustrine oil shales, in the shale member of the Shimengou Formation and the main controlling factors of the formation of the oil shales are ambiguous. This paper aims to reconstruct the lake evolution history during the Middle Jurassic period and reveal its influence on the formation of the oil shales in this area. Oil shales and fine-grained sediments were systematically sampled to determine their mineralogical and geochemical characteristics (major, trace and rare earth elements; stable carbon and oxygen isotopes). Based on lithological variations and total organic carbon (TOC) contents, a complete third-order sequence is identified and can be further divided into four system tracts (lowstand system tract, LST; transgressive system tract, TST; highstand system tract, HST and regressive system tract, RST) that correspond to four lake evolution stages (A–D). Changes in the lake level show an initial shallow lake, followed by a continuous upward deepening trend, followed by a shallowing trend. Shallow lake facies developed in the LST, TST and RST, whereas semi-deep to deep lake facies developed in the HST. Stable carbon and oxygen isotopes indicate that the Shimengou Lake was semi-closed to closed in the Middle Jurassic. Therefore, the water properties responded strongly to climate changes. According to elemental and mineralogical analyses, a moist climate prevailed, except during the early stages of the TST (stage B1) and HST (stage C1) when there was a semiarid climate. The semiarid climate influenced the water properties and detrital input and was the major controlling factor for the formation of the higher quality oil shales within a saline water environment. In comparison, under the moist climatic condition in the HST, the stable semi-deep to deep-water environment was the major controlling factor for the formation of lower quality oil shales within a fresh water environment.

Temporal dynamics of monthly evaporation in Lake Urmia

As a UNESCO biosphere, Lake Urmia is a shallow hypersaline lake which is facing a rapid water surface degradation. Evaporation from the surface of the Lake, as a physical process which accelerates the Lake’s degradation, was evaluated using chaos theory. Seven hydrometeorological stations scattered around the Lake were selected, and a 40-year time span between October 1974 and September 2014 was used at each station. Missing data in time series was removed and the whole time series was tested for consistency, randomness, and presence of trend. Since evaporation at each station was measured by means of class A evaporation pan, time series at each station was multiplied by a pan coefficient to incorporate the effect of saline water and free water surface environment simultaneously. Measurement errors arising from assumption of zero evaporation in winter were removed from the time series using locally weighted scatterplot smoothing method after which unification of time series into a single time series is achieved. Results of the data transformation and information loss were monitored by means of auto-correlation, partial-auto-correlation, mutual information, power spectrum, false nearest neighbor, and correlation dimension. A local prediction method is then used to capture the temporal dynamics of the evaporation with consideration of an appropriate time delay and embedding dimension. Finally, the representative model was projected on a 3-dimensional phase space to evaluate the temporal dynamics of the evaporation. Results indicate that the chaotic approach shows accurate predictions in advance.

Dissolution characteristics of granulated coal ash in different saline water conditions

Granulate coal ash (GCA) has been widely used for improving both sediment and water environments in littoral regions. Dissolved ions from GCA have been pointed out to play an important role in the improvements of sediment and water environments. As the dissolution characteristics of a material in solvent depend on the solvent characteristics, this study attempts to clarify the dissolution characteristics of GCA under different saline water conditions. This may provide useful information for practical uses of GCA in different water environments. The experimental results showed that GCA dissolved more with increasing salinity of solvent. This suggests that GCA is more active in saline water environment rather than freshwater environment. Interestingly, larger releases of calcium ions were confirmed when the solvent salinity was higher than 1000 mg/L. This was because the calcium ions of calcium silicate hydrate (C–S–H) present in GCA were replaced by the sodium ions present in solvent. The solubility of C–S–H present in GCA was low comparing with that of C–S–H gels. Only 40% of the total C–S–H were influenced by the high salinity concentration (higher than 1000 mg/L). Furthermore, a higher solubility of GCA was observed after combusting GCA. Our results suggest that GCA should be combusted at 200 °C prior to use for obtaining a higher performance in improving water and sediment environments.

Innovative approach for suppressing corrosion of SS304 steel in saline water environment

PurposeThe failure of structures and components made of SS304 steel because of corrosion in the presence of saline water environment is still an unsolved issue across the globe. Conventionally, coatings and inhibitors are used to mitigate corrosion. The purpose of this study is to propose a novel method to tackle corrosion by means of micro-patterning on the surface and to explore the relation between surface morphology, corrosion and wetting nature of micro-patterned SS304 Steel.Design/methodology/approachGroove-shaped micro-patterns were created on SS304 steel surface with varying ridge and channel widths. Wettability studies conducted on flat and micro-patterned steel surfaces using high speed camera. Corrosion tests carried out in saline water using an electrochemical test set-up to quantify the performance of micro-patterned surface over flat surface and scanning electron microscopic analysis to visualize the severity of corrosion on the surfaces of SS304 steel.FindingsWettability studies showed that the micro-patterned steel surfaces were hydrophobic. Corrosion rates of the micro-patterned steel surfaces were lower by more than an order of magnitude compared to that of the flat steel surface. Scanning electron microscopic analysis revealed that the micro-patterned steel surfaces had less surface damage compared to the flat surface.Originality/valueThe author shows that the remarkable corrosion resistance shown by the micro-patterned steel surfaces is attributed to their hydrophobicity, which reduced the contact between the surfaces and the corrosive liquid media. Results from the investigation indicate that micro-patterning of SS304 steel surfaces is an effective route to decrease corrosion.

Formation mechanism of carbonates in the lacustrine muddy shale and it implication for shale oil and gas: A case study of source rocks in Member 4 and Member 3 of Shahejie Formation, Dongying sag

Through analysis of microscopic characteristics, mineral components, elements and isotopes, the genetic mechanism of carbonates in the deep lacustrine source rocks in the upper submember of Member 4 and lower submember of Member 3 of Shahejie Formation in Dongying sag, is well investigated. The results show that four types of carbonates in the deep lake, i.e., lenticular coarse crystalline carbonate, lamellar micro-fine crystalline carbonate, lamellar cryptocrystalline carbonate and massive cryptocrystalline carbonate. Of which, the lenticular coarse crystalline carbonate is formed by diagenetic recrystallization. For the lamellar micro-fine crystalline carbonate and the lamellar cryptocrystalline carbonate, through the alga photosynthesis, the carbon dioxide (CO2) is constantly extracted from water, thus the concentration of CO3−2 ion in water increases, and then the CO3−2 ion reacts with Ca2+ ion in lake water surface to form the carbonates; the saline water environment is favorable for preservation of carbonate particles which mostly occur in lamellar micro-fine crystalline; in the brackish water environment, the water is deep, and the carbonate crystalline beneath the carbonate compensation depth surface is usually is dissolved, and most of lamellar cryptocrystalline are preserved. The massive cryptocrystalline carbonate is formed by the sedimentary carbonate which transport from shallow water to deep water by gravity flow. To some extent, the carbonates control reservoir property and compressibility of muddy shale in the upper submember of Member 4 and lower submember of Member 3 of Shahejie Formation in Dongying sag, and provide important information for reconstruction of sedimentary environment of the ancient lake.

Bonding capacity of GFRP sheet for concrete beams strengthening under saline water environment

Structures built in aggressive environments such as in the sea/marine environment need to be carefully designed, due to the possibility of chloride ion penetration into the concrete. One way to reduce the strength degradation in such environment is to use FRP, which is attached to the surface of reinforced concrete using epoxy. A series of the specimen of reinforced concrete beams with dimension 100×120×600 mm were cast. Beams were immersed in the saline water for 3 months (B3), 6 months (B6) and 12 months (B12). Three specimens were prepared to control beam without immersion in the saline water (B0). Write the study presented is focused on determining the effect of the saline water environment to the capacity of GFRP as flexural external reinforcement elements. The result indicated that the bonding capacity of B3, B6, and B12 compared to B0 decrease of 7.91%, 11.99%, and 37.83% respectively. The decreasing was caused by the weakening of the bonding capacity GFRP due to the influence of the saline water environment.

Proof of Concept: Pozzolan Bricks for Saline Water Evaporative Cooling in Controlled Environment Agriculture

Abstract. Control of indoor temperature and humidity is of critical concern for controlled environment agriculture systems in hot, arid regions. Evaporative cooling is a technology utilized for energy-efficient cooling and humidification of these systems. However, the evaporative cooling process consumes considerable amounts of water, as much as 80-90% of the water footprint for indoor food production in these regions. The use of saline water in place of fresh water in evaporative cooling systems offers a potential solution for greatly improving the sustainability of these systems. However, the use of saline water in industry-standard cellulose pad systems can cause premature clogging of the porous medium, leading to system failure and the need for porous media replacement. A new evaporative cooling technology consisting of crushed pozzolan volcanic rock formed into porous bricks was evaluated for use in controlled environment agriculture systems using saline water. Two brick designs were tested for proof of concept cooling of commercial-scale greenhouses. Temperature-based cooling efficiencies of the bricks were achieved that are comparable to cellulose pads. In addition, the pozzolan-based bricks showed impressive resistance to saline water and harsh environments, requiring no replacement over the duration of the experimental trials. The integration of the pozzolan evaporative cooling systems using sea or brackish water with a water-saving growing technology, such as recirculating aquaponics or hydroponics, shows promise for reducing the fresh water footprint of food raised indoors in hot, dry environments by as much as 80%-90%. Keywords: Controlled environment, Evaporative cooling, Pozzolan, Salt, Water conservation.

Groundwater Microbial Communities Along a Generalized Flowpath in Nomhon Area, Qaidam Basin, China.

Spatial distribution (horizonal and vertical) of groundwater microbial communities and the hydrogeochemistry in confined aquifers were studied approximately along the groundwater flow path from coteau to plain in the Nomhon area, Qinghai-Tibet plateau, China. The confined groundwater samples at different depths and locations were collected in three boreholes through a hydrogeological section in this arid and semi-arid area. The phylogenetic analysis of 16S rRNA genes and multivariate statistical analysis were used to elucidate similarities and differences between groundwater microbial communities and hydrogeochemical properties. The integrated isotopic geochemical measurements were applied to estimate the source and recharge characteristics of groundwater. The results showed that groundwater varied from fresh to saline water, and modern water to ancient water following the flowpath. The recharge characteristics of the saline water was distinct with that of fresh water. Cell abundance did not vary greatly along the hydrogeochemical zonality; however, dissimilarities in habitat-based microbial community structures were evident, changing from Betaproteobacteria in the apex of alluvial fan to Gammaproteobacteria and then to Epsilonproteobacteria in the core of the basin (alluvial-lacustrine plain). Rhodoferax, Hydrogenophaga, Pseudomonas, and bacterium isolated from similar habitats unevenly thrived in the spatially distinct fresh water environments, while Sulfurimonas dominanted in the saline water environment. The microbial communities presented likely reflected to the hydrogeochemical similarities and zonalities along groundwater flowpath.

The impact of increased oxygen conditions on heavy metal flocculation in the Sefidrud estuary

Similar to natural filters, estuaries are capable of removing considerable amounts of heavy metal from rivers that flow into saline water environments by turning the metal into flocs. The research objective was to investigate the self-purification potential of estuaries in removal of metal by flocculation processes. Hence, flocculation of metal was studied experimentally in 5 aquaria with varying salinity levels. Subsequently, experiment was repeated while dissolved oxygen increased. Results indicated that at higher dissolved oxygen, the flocculation rates of Mn, Ni, and Pb increased by 9%, 20%, and 26%, respectively. However, Zn and Cu showed 23% and 26% of decrease in flocculation rate, respectively. In the analysis of the relationship between oxidation reduction potential and estuarine water quality it was found that ORP escalated with an increase in the dissolved oxygen. This finding suggests that ORP can be used to govern the potential of flocculation processes at estuarine zone.

Influence of Distinct Environment on the Mechanical Characteristics of Arhar Fiber Polymer Composites

Over the past decades the need for eco-friendly, non-toxic and biodegradable material is growing significantly. Natural fiber polymer composites have become the prior choice for many applications, as the natural fiber polymer composites are economical and eco-friendly materials in contrast with synthetic fiber reinforced composites. In the current study arhar fiber is used as a reinforcing material. Arhar fiber epoxy composites are fabricated using the hand lay-up technique. The materials were tested for weight gain in different environments (saline water, mineral water and subzero temperature condition). The composite samples immersed in the different environments were tested for tensile strength. It is observed that weight gain is more in mineral water and saline water, minimum weight gain is observed in subzero condition. Maximum tensile strength is observed in 10%fiber content samples. Strength depreciation ismore in samples immersed in the saline water environment.

Smectite-illitization difference of source rocks developed in saline and fresh water environments and its influence on hydrocarbon generation: A study from the Shahejie Formation, Dongying Depression, China

Samples of argillaceous source rocks from three sub-members of the Shahejie Formation (Es) in the Dongying Depression, China, were collected to investigate the differences in hydrocarbon generation among the sub-members, which developed in fresh (Es32, Es33) and saline (Es41) water environments. Pyrolysis, XRD and thermo-XRD analyses were used to compare the characteristics of organic matter (OM), clay minerals and OM occurrences. Total organic carbon and hydrocarbon potential proxies suggest that the samples from Es33 were much better than the other two intervals, which agrees with previous studies. The characteristics of clay minerals suggest that the samples from Es41 have the most abundant illite, with a maximum illite percentage in mixed-layer illite-smectite (ISm), and the best crystallinity of ISm with a main stacking mode of R1.5. However, the stacking modes of ISm in Es32 and Es33 were primarily R0 and R1, respectively, and the crystallinity was relatively poor. Thus, the smectite illitization process was faster in Es41 than in the other two intervals, and a saline environment was a primary cause for the acceleration of the process. Moreover, OM occurrence indicates that the samples from Es41 had the lowest amount of interlayer OM, whereas Es33 had the largest amount. Therefore, the rapid illitization in Es41 caused abundant interlayer OM to be desorbed and discharged, which in turn caused the amount of residual interlayer OM in Es41 to be less than that in the other two intervals. Thus, the source rocks of Es41 made a more significant contribution to hydrocarbon generation than those of the other two units. In conclusion, the inconsistent illitization among these intervals was a major cause of the differences in hydrocarbon generation.

Comparative Performance of Corn, Sorghum and Pearl Millet Growing under Saline Soil and Water Environments in Aral Sea Basin

Comparative Performance of Corn, Sorghum and Pearl Millet Growing under Saline Soil and Water Environments in Aral Sea Basin

Does selection in a challenging environment produce Nile tilapia genotypes that can thrive in a range of production systems?

This study assessed whether selection for high growth in a challenging environment of medium salinity produces tilapia genotypes that perform well across different production environments. We estimated the genetic correlations between trait expressions in saline and freshwater using a strain of Nile tilapia selected for fast growth under salinity water of 15–20 ppt. We also estimated the heritability and genetic correlations for new traits of commercial importance (sexual maturity, feed conversion ratio, deformity and gill condition) in a full pedigree comprising 36,145 fish. The genetic correlations for the novel characters between the two environments were 0.78–0.99, suggesting that the effect of genotype by environment interaction was not biologically important. Across the environments, the heritability for body weight was moderate to high (0.32–0.62), indicating that this population will continue responding to future selection. The estimates of heritability for sexual maturity and survival were low but significant. The additive genetic components also exist for FCR, gill condition and deformity. Genetic correlations of harvest body weight with sexual maturity were positive and those between harvest body weight with FCR were negative. Our results indicate that the genetic line selected under a moderate saline water environment can be cultured successfully in freshwater systems.

The origin and distribution of crude oil in Zhu III sub-basin, Pearl River Mouth Basin, China

The origin of thirteen major oil fields in Zhu III sub-basin, Pearl River Mouth Basin, was studied by using the results of Rock-Eval pyrolysis on 340 samples and biomarker analysis on 18 source rock samples and 33 oil samples. The two possible source rock intervals have different biomarker assemblages and were deposited in different environments. The Eocene Wenchang Formation (E2w, 49.5–35 Ma) is characterized by high hopane/sterane ratio (>37.84), high 4-methyl sterane index (0.28–1.06), low gammacerane index (<0.09), low extended tricyclic terpane ratio [ETR=(C28 + C29)/(C28+C29 + Ts), 0.13–0.20] and bicadinane/C30 hopane (<0.02), which was deposited in fresh-brackish water and dominated by algae. On the contrary, Oligocene Eenping Formation (E3e, 35–30 Ma) has high gammacerane index (>0.10), high bicadinane/C30 hopane (up to 73.62) but low hopane/sterane ratio (<12.50), and it was deposited in relative saline water environment with significant high terrestrial plant debris input. Because of complex geologic settings, oils have different distribution. By using oil-source correlation analysis and hierarchical cluster analysis, two source-related oil groups were identified. Oils found in the Wenchang A depression and Yangjiang uplift, which are classified to oil group 1, were derived from E3e. Oils found in the Wenchang B depression and Shenhu uplift, which are classified to oil group 2, were derived from both E2w and E3e source rocks. But the Qionghai uplift received supply from both the Wenchang A and B depression. This distribution pattern is also proven by using a simple three-dimensional model called PathWay™. An explanation was put forward in this paper about the oils in Zhu III sub-basin and four potential petroleum accumulations were roughly predicted where no well drilled.

Reduction in Fully Softened Shear Strength of Natural Clays with NaCl Leaching and Its Effect on Slope Stability

AbstractLandslides and slope failures in natural clay-rich materials are frequently observed in coastal areas and other areas where these materials were deposited in a saline water environment. High sodium chloride (NaCl) concentration in the pore fluid results from deposition in this environment. As shown by the results of this study, subsequent reduction in the NaCl concentration results in reduction in fully softened shear strength, with potentially significant reduction in slope stability. Fourteen sample materials were collected from seven different landslide areas in Niigata Prefecture, Japan, to evaluate the effect of saline water on fully softened shear strength (FSSS). The sample materials were collected from the intact mudstones and the sliding surface materials. Pore waters from the powdered sliding surface materials exhibited low concentrations of NaCl; however, the pore waters in the powdered intact rock samples exhibited a high concentration of NaCl. Washing of NaCl from the powdered intact ...

Measurement of Mud Floc—Settling Velocity Using a Laser Diffraction Particle Size Distribution Analyzer

In-situ and laboratory measurements of particle setting velocity through different techniques, such as settling tubes and video systems, suffer from human and random sampling errors and lack of accuracy. The development of a method to improve the accuracy of the settling velocity measurements has been a challenge for researchers. We propose a method using a laser diffraction particle size distribution analyzer (Shimadzu, SALD-2000J) to estimate the particle settling velocity with increased accuracy. SALD-2000J measures continuously the average intensity of light scattered and the particle size distribution of mud flocs, which were used to estimate the particle settling velocities. The SALD-2000J method produced high accurate results saving both labor and time. The predicted settling velocity presented the same order of magnitude of those reported in previous studies. The settling velocity was used in the simulation of particle size distribution variation, producing a relative error of particle size distributions (obtained from SALD-2000J and the simulation) interior to 5%. The results suggested that the proposed method can be applied to the prediction of settling velocities of mud flocs and inorganic particles both in fresh and saline water environments.

Genesis study of high abundant 17α(H)-diahopanes in Lower Cretaceous lacustrine source rocks of the Lishu Fault Depression, Songliao Basin, Northeast China

Relatively abundant 17α(H)-diahopanes have been detected in the lower cretaceous lacustrine source rocks from the Lishu Fault Depression in the Songliao Basin Northeast China. Rich long chain tricyclic terpanes (carbon number up to C35) and gammacerane have been observed in those source rocks with relatively abundant 17α(H)-diahopanes, which is rarely seen in previous reports. In this paper, the formation of 17α(H)-diahopanes has been discussed from three aspects including maturity, oxidation-reduction nature of depositional environment and parent material composition by the GC/MS analyses. The results reveal that maturity and oxidation-reduction nature of depositional environment have little effect on the formation of 17α(H)-diahopanes in the investigated area. However, the positive correlation between long-chain tricyclic terpanes and 17α(H)-diahopanes argues strongly for a common origin, and the origin is related to the algaes in saline water environment. The algaes in saline water environment may be a kind of origin of 17α(H)-diahopanes.