Marine Bioactive Steryl Esters from the Red Sea Black Coral Antipathes dichotoma

Two new marine steryl hexadecanoates, 3β‐hexadecanoylcholest‐5‐en‐7‐one ( 1 ) and 3β‐hexadecanoylcholest‐5‐en‐7β‐ol ( 2 ), along with seven known compounds, cholest‐5‐en‐3β‐yl‐formate ( 3 ), thymidine ( 4 ), indole‐3‐carboxaldehyde ( 5 ), 3β‐hydroxycholest‐5‐en‐7‐one ( 6 ), cholesterol ( 7 ), 22‐dehydrocholestrol ( 8 ), and 24‐methylenecholesterol ( 9 ), were isolated from the anthozoan black coral, Antipathes dichotoma. The structures of all isolated compounds were determined by interpretation of their spectral data 1D (¹H, ¹³C and DEPT) and 2D (COSY, HSQC and HMBC) NMR, UV, IR, and MS. Compounds 1 – 5 were evaluated for their anticancer activities, employing four cancer panels; HepG2, WI 38, VERO, and MCF‐7. All tested compounds, except 4 , showed moderate activities. Compound 4 exhibited significant anticancer activity against VERO and MCF‐7, with IC₅₀ 20.5 and 20.2 µg/mL, respectively.     

Remote Sensing and GIS based groundwater potential mapping for sustainable water resource management of Lidder catchment in Kashmir Valley,India

The valley of Kashmir is blessed with abundant water resources. However, high population growth and concentration of population at favorable locations have resulted in increased demand for water. The problem is further aggravated in Lidder catchment where unplanned tourism development has resulted in deterioration of water quality. Multi-Criteria Evaluation (MCE) approach is adopted using IRS P6 LISS III satellite data 2010, geological map published by Geological Survey of India, toposheets prepared by Survey of India, 1961 and field observation. Seven thematic layers (slope, lineament density, drainage density, soil, geology, geomorphology and land use land cover) are generated in GIS environment and weighted according to their relative relevance to groundwater occurrence. Knowledge-based weights and ranks are normalized, and a weighted linear combination technique is adopted to determine the groundwater potential (GWP). The catchment is divided into five zones of very high, high, medium, low and very low GWP. The results show that 50.22% of the total catchment area, which is uninhabited, has very low GWP. However, the densely populated southern part of the catchment has moderate to very high GWP. The study demonstrates that MCE using remote sensing and GIS technology could be efficiently employed as a very useful tool for the assessment and management of groundwater resources especially in regions where data is poor.     

Precursors of Copepod Abundance in the Gulf of Maine in Atmospheric Centers of Action and Sea Surface Temperature

Interannual variations of total copepod abundance in the Gulf of Maine (1961-1991) are analyzed and related to the semi-permanent atmospheric pressure systems: Icelandic Low (IL) and the Azores High (AH). These centers of action dominate atmospheric and oceanic circulation in the North Atlantic. Cross-correlation analysis of zooplankton, sea surface temperature (SST) and the atmospheric characteristics have revealed different (from one to three years) time lags between the above characteristics. A multiple stepwise regression analysis gave a correlation value of 0.7 between observed and predicted interannual changes of total copepod abundance. A discussion is included of possible mechanisms that may contribute to the dynamic links that transfer atmospheric variation into observed changes in zooplankton abundance.     

Application of Land Magnetic and Geoelectrical Techniques for Delineating Groundwater Aquifer: Case Study in East Oweinat,Western Desert,Egypt

Natural Resources Research - Two geophysical tools were used to delineate the configuration of the Nubian sandstone aquifer in the study area. Three hundred magnetic points were measured and...     

A remote sensing contribution to hydrologic modelling in arid and inaccessible watersheds,Pishin Lora basin,Pakistan

The lack of adequate field measurements often hampers the construction and calibration of rainfall‐runoff models over many of the world's watersheds. We adopted methodologies that rely heavily on readily available remote sensing datasets as viable alternatives for assessing, managing, and modelling of such remote and inadequately gauged regions. The Soil and Water Assessment Tool was selected for continuous (1998–2005) rainfall‐runoff modelling of one such area, the northeast part of the Pishin Lora basin (NEPL). Input to the model included satellite‐based Tropical Rainfall Measuring Mission precipitation data, and modelled runoff was calibrated against satellite‐based observations, the latter included: (i) monthly estimates of the water volumes impounded by the Khushdil Khan (latitude 30°40′N, longitude 67°40′E), and the Kara Lora (latitude 30°34′N, longitude 66°52′E) reservoirs, and (ii) inferred wet versus dry conditions in streams across the NEPL. Calibrations were also conducted against observed flow reported from the Burj Aziz Khan station at the NEPL outlet (latitude 30°20′N; longitude 66°35′E). Model simulations indicate that (i) average annual precipitation (1998–2005), runoff and recharge in the NEPL are 1300 × 10⁶ m³, 148 × 10⁶ m³, and 361 × 10⁶ m³, respectively; (ii) within the NEPL watershed, precipitation and runoff are high for the northeast (precipitation: 194 mm/year; runoff: 38 × 10⁶ m³/year) and northwest (134 mm/year; 26 × 10⁶ m³/year) basins compared to the southern basin (124 mm/year; 8 × 10⁶ m³/year); and (3) construction of delay action dams in the northeast and northwest basins could increase recharge from 361 × 10⁶ m³/year up to 432 × 10⁶ m³/year and achieve sustainable extraction. The adopted methodologies are not a substitute for traditional approaches, but they could provide first‐order estimates for rainfall, runoff, and recharge in the arid and semi‐arid parts of the world that are inaccessible and/or lack adequate coverage with field data. Copyright © 2011 John Wiley & Sons, Ltd.     

Geophysical Constraints on the Hydrogeologic and Structural Settings of the Gulf of Suez Rift-Related Basins: Case Study from the El Qaa Plain,Sinai, Egypt

Groundwater has been identified as one of the major freshwater sources that can potentially meet the growing demands of Egypt’s population. Gravity data (from 381 ground gravity stations) were collected, processed, and analyzed together with the available aeromagnetic (800 line-km) data to investigate the hydrogeologic and structural settings, areal distribution, geometry, and water storage of the aquifers in El Qaa coastal plain in the southwest Sinai Peninsula, and to assess their longevity given projected extraction rates. Findings include (1) complete Bouguer anomaly and total magnetic intensity maps show two connected sub-basins separated by a narrow saddle with an average basin length of 43 km and an average width of 12 km; (2) two-dimensional modeling of both gravity and magnetic data indicates basin fill with a maximum thickness of 3.5 km; (3) using anomalous residual gravity, the volume of water in storage was estimated at 40–56 km³; and (4) progressive increases in extraction rates over time will deplete up to 40 % of the aquifers’ volume in 200–230 years and will cause the water quality to deteriorate due to seawater intrusion in 45 years. Similar geophysical exploration campaigns, if conducted over the entire coastal plains of the Red Sea and the Gulfs of Suez and Aqaba, could assist in the development of sound and sustainable management schemes for the freshwater resources in these areas. The adopted techniques could pave the way toward the establishment of sustainable utilization schemes for a much larger suite of similar aquifers worldwide.     

Assessing and Improving Land Surface Model Outputs Over Africa Using GRACE,Field, and Remote Sensing Data

The Gravity Recovery and Climate Experiment (GRACE), along with other relevant field and remote sensing datasets, was used to assess the performance of two land surface models (LSMs: CLM4.5-SP and GLDAS-Noah) over the African continent and improve the outputs of the CLM4.5-SP model. Spatial and temporal analysis of monthly (January 2003–December 2010) Terrestrial Water Storage (TWS) estimates extracted from GRACE (TWS_GRACE), CLM4.5-SP (TWS_CLM4.5), and GLDAS-Noah (TWS_GLDAS) indicates the following: (1) compared to GRACE, LSMs overestimate TWS in winter months and underestimate them in summer months; (2) the amplitude of annual cycle (AAC) of TWS_GRACE is higher than that of TWS_LSM (AAC: TWS_GRACE > TWS_GLDAS > TWS_CLM4.5); (3) higher, and statistically significant correlations were observed between TWS_GRACE and TWS_GLDAS compared to those between TWS_GRACE and TWS_CLM4.5; (4) differences in forcing precipitation and temperature datasets for GLDAS-Noah and CLM4.5-SP models are unlikely to be the main cause for the observed discrepancies between TWS_GRACE and TWS_LSM; and (5) the CLM4.5-SP model overestimates evapotranspiration (ET) values in summer months and underestimates them in winter months compared to ET estimates extracted from field-based (FLUXNET-MTE) and satellite-based (MOD16 and GLEAM) ET measurements. A first-order correction was developed and applied to correct the CLM4.5-derived ET, soil moisture, groundwater, and TWS. The corrections improved the correspondence (i.e., higher correlation and comparable AAC) between TWS_CLM4.5 and TWS_GRACE over various climatic settings. Our findings suggest that similar straightforward correction approaches could potentially be developed and used to assess and improve the performance of a wide range of LSMs.     

Morphological control of slope instability in contourites: a geotechnical approach

Contourite drifts are sediment bodies formed by the action of bottom currents. They are common features found on continental slopes and are often affected by slope failure. However, processes controlling slope instability in contourite depositional systems are still not well constrained, and it is not clear whether contourites have particular properties that make them more susceptible to slope failure. In this study, we compare sedimentological and geotechnical properties of contouritic and hemipelagic sediments within the Corsica Trough (northern Tyrrhenian Sea) using geophysical data sets and sediment cores in order to get a better understanding of the controlling factors of slope stability. Geomorphological and slope stability analyses reveal that differences in sediment properties have little influence on the location of submarine landslides, in comparison with the morphology of the drifts. Hence, the steep downslope flanks of plastered drift deposits are the most susceptible zones for local failure initiation. Moreover, as erosion is common at the foot of plastered drifts, undercutting is thought to contribute to the development of large-scale failure up to the point that submarine landslides are triggered.