Isolation and characterization of two crude oil-degrading yeast strains, Yarrowia lipolytica PG-20 and PG-32, from the Persian Gulf

Among six crude oil-degrading yeasts that were isolated from an oil-polluted area in the Persian Gulf, two yeast strains showed high degradation activity of aliphatic hydrocarbons. From an analysis of 18S rRNA sequences and biochemical characteristics, these strains were identified as Yarrowia lipolytica strains PG-20 and PG-32. Gas Chromatography (GC) analysis of the crude oil remaining in the culture medium after 1 week at 30°C showed that the strains PG-20 and PG-32 degraded 68% and 58% of crude oil, respectively. The optimal growth condition and biodegradation of hydrocarbons was in ONR medium with an acidic pH (pH5). These two strains may degrade aliphatic hydrocarbons more efficiently than aromatic hydrocarbons, although strain PG-20 had better degradation than strain PG-32. The two Y. lipolytica strains reduce surface tension when cultured on hydrocarbon substrates (1% v/v). These strains showed a cell surface hydrophobicity higher than 70%. These results suggested that Y. lipolytica strains PG-20 and PG-32 have high crude oil degrading activity due to their high emulsifying activity and cell hydrophobicity. In conclusion, these yeast strains can be useful for the bioremediation process in the Persian Gulf and decreasing oil pollution in this marine ecosystem.     

Concentrations of trace elements in muscle of sturgeons in the Caspian Sea

Concentrations of 21 trace elements were determined in muscle of beluga (Huso huso), Persian sturgeon (Acipenser persicus), Russian sturgeon (Acipenser gueldenstaedtii), ship sturgeon (Acipenser nudiventris) and stellate sturgeon (Acipenser stellatus) collected from coastal regions of Azerbaijan, Iran, Kazakhstan and Turkmenistan, surrounding the Caspian Sea during 2000-2001. Concentrations of Mn, Co, Cu, Mo, Sn, Hg, Pb and Bi in the muscle were apparently different among the five species of sturgeons. Especially, beluga showed the highest concentrations of Hg, Pb and Mn in all the five species. In addition, more than half of the individuals of beluga exceeded the guideline level (0.3 microg/g wet wt.) of Hg for food in UK. However, V, Cr, Zn, Ga, Rb, Sr and Ba concentrations were similar among five sturgeons. Growth-dependent increase in Hg in beluga, Cu in Persian sturgeon, and Zn in Russian sturgeon were observed, whereas V, Mn, Co, Cu, Ga, Sr, Mo, Sn, Hg and Bi concentrations in Persian sturgeon, Pb in ship sturgeon, and Cr, Mn, and Rb in stellate sturgeon were negatively correlated with body length. All species of sturgeon in Azerbaijan showed the highest concentration of Sr and the lowest concentration of Rb, while the five sturgeons from Iran showed opposite trends. Concentration of V, which is present in oil, in sturgeons in the Caspian Sea was considerably lower than that of fish from Kuwait, but was comparable to that of Cambodia and the Gulf and Gulf of Oman. To our knowledge, this study provides the first extensive data on multielemental accumulation in sturgeons of the Caspian Sea.     

The nonstationary and nonlinear character of Caspian Sea level variations

A stochastic model of level variations in a drainless water body is considered. The model accounts for the nonstationary character of sea level under stationary climate. It is shown that in the case of the Caspian Sea, the range from ?29 to ?26 m BS corresponds to a relative stability of the level because of the greatest gentleness of the shores and shelf slope in combination with the maximal water outflow into Kara-Bogaz-Gol Gulf.     

Isolation and characterization of alkane degrading bacteria from petroleum reservoir waste water in Iran (Kerman and Tehran provenances)

Petroleum products spill and leakage have become two major environmental challenges in Iran. Sampling was performed in the petroleum reservoir waste water of Tehran and Kerman Provinces of Iran. Alkane degrading bacteria were isolated by enrichment in a Bushnel–Hass medium, with hexadecane as sole source of carbon and energy. The isolated strains were identified by amplification of 16S rDNA gene and sequencing. Specific primers were used for identification of alkane hydroxylase gene. Fifteen alkane degrading bacteria were isolated and 8 strains were selected as powerful degradative bacteria. These 8 strains relate to Rhodococcus jostii, Stenotrophomonas maltophilia, Achromobacter piechaudii, Tsukamurella tyrosinosolvens, Pseudomonas fluorescens, Rhodococcus erythropolis, Stenotrophomonas maltophilia, Pseudomonas aeruginosa genera. The optimum concentration of hexadecane that allowed high growth was 2.5%. Gas chromatography results show that all strains can degrade approximately half of hexadecane in one week of incubation. All of the strains have alkane hydroxylase gene which are important for biodegradation. As a result, this study indicates that there is a high diversity of degradative bacteria in petroleum reservoir waste water in Iran.     

The Urquiola oil spill,La Coruña,Spain: Case history and discussion of methods of control and clean-up

A massive oil spill affected approximately 215 km of coastline as a result of the grounding and subsequent explosion of the supertanker Urquiola at the entrance to the harbour at La Coruña, Spain, on 12 May 1976. A total of 99–100 000 tons of Persian Gulf crude oil was lost, most of which burned, but an estimated 25–30 000 tons washed ashore. Over 2000 tons of dispersants were applied to the oil at sea. Land-based clean-up and control methods were largely inadequate to combat the spread of oil, and were ineffective at preventing large scale environmental damage.     

南海油气资源潜力及勘探现状

南海的油气资源极为丰富,享有“第二个波斯湾”的美誉.南海地貌类型多样,地形复杂,其战略位置极为重要,是东亚及相邻各国必经之路.资源之争,使得周边各国使出浑身解数,发展海洋经济与技术,1981年至2002年,越南就从南沙海域的油田中开采了1亿吨石油、15亿多立方米的天然气,获利250亿美元,南海石油已成为越南国民经济的第一大支柱产业.近半世纪中国南海油气勘探工作取得巨大的成就,发现了26个新生代盆地,取得了南海海域的基本石油地质成果,为南海的勘探开发奠定了基础.南海具有巨大的勘探空间及技术发展空间,每一次的技术进步,都会带来南海油气勘探的质的飞跃.     

Aliphatic and aromatic hydrocarbons in coastal Caspian Sea sediments

This investigation represents the first extensive study of the spatial distribution and sources of aliphatic (n-alkanes and unresolved complex mixture of fossil hydrocarbons) and polycyclic aromatic hydrocarbons (PAHs) in coastal sediments from the Caspian Sea. PAH concentrations, n-alkanes and biomarker profiles all suggested that there was limited petrogenic contamination in the shallow North Caspian Sea sediments, which are coarse with a low total organic carbon content. In contrast, moderate to high petrogenic contamination was found in the South Caspian Sea, in particular in the offshore oil fields near Baku, Azerbaijan. Contaminant patterns indicated that the PAHs were mainly from fossil sources, with higher contributions of pyrolytic only near industrialized and urban areas. A high contribution of perylene, a geochemically derived PAH, to the total PAHs was found in the west and south at sites influenced by the Kura, Safid Rud, Terek, Sulak and Samur Rivers.     

Hydrocarbons in the modern sediments of the Caspian Sea

The presented results have been obtained in a study of the concentrations and composition of aliphatic and polycyclic hydrocarbons in bottom sediments of Volga delta branches and in its shallow zone (2009–2010), as well as the Caspian Sea proper (2010–2013). Oil hydrocarbon pollution has been found to manifest itself mostly in Volga delta branches, which, despite the low concentrations (up to 54.5 μg/g), showed higher hydrocarbons share in C_org (up to 33.8%), while the composition of alkanes suggested their oil genesis. The geochemical barrier the Volga–the Caspian Sea prevents anthropogenic hydrocarbons from entering the open parts of the Caspian. Bottom sediments in the shallow zone of the Northern Caspian, represented by coarse-grained material, are now polluted by oil hydrocarbons to a lesser extent compared with other areas. The highest concentrations of aliphatic hydrocarbons (up to 178 μg/g) were recorded in the deepsea bottom sediments of Derbent Depression and in depressions of the Middle and Southern Caspian. These areas show a higher concentration of C_org (up to 9.884%) and a low concentration of hydrocarbons in C_org (up to 0.16%), while odd high-molecular homologues (n-C₂₅–C₃₁) dominate in the composition of alkanes.     

Long-Term variations in water levels in the Volga mouth area and their dependence on the Caspian Sea level variations

Long-term water level variations in the Volga mouth area and the effect exerted on them by the river’s flow and the Caspian Sea’s level variations are considered. Quantitative relationships were identified between the mean annual water levels at different gages in the mouth and the sea level. A backwater component was isolated in the long-term variations in water level in the Volga mouth area. Relationships between the daily water levels in the mouth and the Caspian Sea’s level at fixed water flow in the delta apex are presented. The magnitude and the propagation distance of backwater from the sea into the delta are specified. The responses of the mouth areas of rivers emptying into the Caspian Sea to sea level variations in the past century are compared.     

Current Variations in the Wind Speed Vector and the Rate of Evaporation from the Caspian Sea Surface

Regularities in the rearrangement of the surface atmospheric circulation in the Caspian Sea region are studied. It is found that during the current rise in the Caspian Sea level, a statistically significant decrease in the wind speed modulus occurred (mainly in autumn and winter winds of zonal directions). This caused a decrease in the rate of evaporation in the region. The results of this study testify to a need for developing a deterministic model of current variations in the Caspian Sea water regime at varying global and regional climate.     

Plasmid incidence in marine bacteria isolated from petroleum polluted sites on different petroleum hydrocarbons

Oil-degrading bacteria isolated from oil spills, an industrial bay, and an offshore oil field by liquid enrichment on crude oils and polynuclear aromatic hydrocarbon compounds were screened for extra-chromosomal DNA. Plasmids were detected in 21% of the strains isolated on whole crude oil and in 17% of the strains isolated on polynuclear aromatic hydrocarbons. Multiple plasmids were observed in 50% of the plasmid-containing strains. Pseudomonas was the predominant genus isolated during the study. Plasmids do not appear to be of importance to these strains during degradation of freshly introduced oil at a nonpolluted site such as might be the case in an ocean oil spill. Plasmids do appear to be significant in the adaptation of Pseudomonas species to chronic petroleum pollution.     

Numerical Simulation of the Caspian Sea Circulation Using the Marine and Atmospheric Research System

The Marine and Atmospheric Research System (MARS) for the Caspian Sea meteorological characteristics is presented, which is implemented in Zubov State Oceanographic Institute. It includes computation of the atmospheric forcing with the Weather Research and Forecasting model, as well as computation of currents, sea level, temperature, salinity and sea ice with the Institute of Numerical Mathematics Ocean Model and the computation of wind wave parameters using the Russian wind-wave model. The results are presented on verification of the hydrometeocharacteristics simulated with the MARS for the Caspian Sea. As well, the retrospective simulation of the thermohydrodynamic characteristics in this basin is performed with MARS for the ice-free period 2003–2013. The important features of the Caspian Sea circulation are shown.     

Sediment PAH: Contrasting levels in the Caspian Sea and Anzali Wetland

A comparative study of 23 PAH congeners in sediment of the Caspian Sea coast and Anzali Wetland was conducted in 2010. Surface sediment was analyzed using chromatography and mass spectrometry. Total PAH concentrations ranged between 212 and 9009 ng g⁻¹ dw. Spatial distribution maps revealed that PAH levels were higher in the coastal areas of the Caspian Sea where oil related activities have been common since 1800’s. Diagnostic ratios analysis indicated that PAHs largely originated from petrogenic processes. PAH toxicity level was assessed using sediment quality guidelines and toxic equivalent concentrations to determine toxic effects on marine organism. Based on these investigations, in our study areas, the probability of toxicity for benthic organisms is “low to medium”. The toxic equivalent concentrations of carcinogenic PAHs varied between 11 and 231 ng TEQ/g; higher total toxic equivalent concentrations values were found in the coastal areas of the Caspian Sea.     

Macro- and microelements in the interstitial water of deep-water areas of the Southern and Middle Caspian Sea

The results of determinations of macro- and microelement concentrations (Mn, Fe, Ba, Sr, Rb, Si, Pb, and U) in the interstitial water in four cores of bottom sediments sampled in the deep-water areas of the Southern and Middle Caspian Sea are compared with the concentrations of these elements in the free water of the Caspian Sea. The data obtained amplify the present-day concept on the geochemical and ecological states of the sea.     

Regime of water balance components of the Caspian Sea

The results of studying the hydrological regime of the Caspian Sea and its basin climate in observation period 1945–2010 are generalized. The results of analysis of the regime of precipitation, air temperature in the Caspian Sea basin and its level, as well as Volga runoff in periods of Caspian Sea level rise and drop are given. The conformity in variations of the trends in Caspian Sea level its basin climate is demonstrated, and the direction of further studies is substantiated.     

Elision and Infiltration Waters in the Northern Caspian

Elision and infiltration groundwater of the Northern Caspian basin are described. It is shown that a zone of elision brines with a high formation pressure exists under the Caspian Sea. These brines are shown to penetrate from below the Caspian Sea into the underground beds, carry fluids, and facilitate the formation of hydrocarbon fields.     

Cytochrome P4501A expression,chemical contaminants and histopathology in roach,goby and sturgeon and chemical contaminants in sediments from the Caspian Sea,Lake Balkhash and the Ily River Delta,Kazakhstan

Roach, goby and sturgeon were examined for cytochrome P4501A (CYP1A) expression and histopathology, in relation to contaminant burdens in fish and sediment. Gradients of induction of CYP1A were observed. Roach from the Ural and Ily River Deltas and roach and goby from the two stations nearest the Caspian Sea oil fields displayed higher levels of CYP1A expression in several organs than was observed in fish from further offshore. Great sturgeon and Russian sturgeon showed higher levels of CYP1A expression than was seen in starred sturgeon and gobies in the Ural delta. No fish showed evidence of contaminant-related histopathologies in the organs examined, despite the elevated CYP1A levels. Low levels of polychlorinated biphenyls and elevated levels of inshore and riverine petroleum hydrocarbons from these habitats suggest that this ongoing hydrocarbon exposure, and that from natural sources and long-term oil exploration on the Northeastern Caspian shore, contributed to the CYP1A induction observed.     

History and Causes of Variations in the Caspian Sea Level: the Miopliocene, 7.1–1.95 Million Years Ago

It is shown that the awareness of the regularities and causes of variations in the Caspian Sea level from the moment of its origin as an isolated lake basin in the Late Miocene (7.2 mln years ago) is of great importance for paleohydrology. Out of the seven principal hydrologic stages of the Caspian Sea history, four stages are considered in this paper: two lake stages (the Late Miocene and Middle Pliocene), the intermediate stage when the Caspian and Zanklinian basins were connected, and the stage of the Manych runoff. An important fact in the Caspian Sea history is emphasized: penetration of the Akchagylian fauna forebears into the Caspian Sea Basin through the Black Sea and the nowadays nonexistent Kuban–Terek Channel (between 5.3 and 3.3 mln years ago). Three phases of penetration of the Mediterranean Zanklinian fauna into the Caspian Basin are recognized. The channel became closed during the Middle Pliocene phase of the Great Caucasian Range elevation (3.3–2.5 mln years ago). This isolation of the Caspian Basin caused the formation of the Great Akchagylian Lake. Its water washed out the New Manych Channel 2.5 mln years ago. From this moment on, the events that occurred in the Caspian Basin and in the Black and Mediterranean seas can be correlated in greater detail, link by link, within the 413-thousand-year period of water abundance.     

Distribution of petroleum hydrocarbons and organochlorinated contaminants in marine biota and coastal sediments from the ROPME Sea Area during 2005

The composition and spatial distribution of various petroleum hydrocarbons (PHs), comprising both aliphatic and polycyclic aromatic hydrocarbons (PAHs), and selected chlorinated pesticides and PCBs were measured in biota and coastal sediments from seven countries in the Persian Gulf and the Gulf of Oman (Bahrain, Iran, Kuwait, Oman, Qatar, Saudi Arabia and the United Arab Emirates). Evidence of extensive marine contamination with respect to organochlorinated compounds and PHs was not observed. Only one site, namely the BAPCO oil refinery in Bahrain, was considered to be chronically contaminated. Comparison of the results from this survey for Σ DDTs and Σ PCBs in rock oysters from the Gulf of Oman with similar measurements made at the same locations over the past two decades indicates a temporal trend of overall decreasing Σ PCB concentrations in oysters, whereas Σ DDTs levels have little changed during that period.     

Vertical Water Exchange in the Caspian Sea Assessed by the Distribution of Transient Tracers

Water Resources - The reliability of various scenarios of vertical structure formation in Caspian Sea water was analyzed based on the distribution of transient tracers (CFC-11, CFC-12, 3H, and 3He)...