Nutrient inputs from submarine groundwater discharge on the Santiago reef flat, Bolinao, Northwestern Philippines     

Senal MI  Jacinto GS  San Diego-McGlone ML  Siringan F  Zamora P  Soria L  Cardenas MB  Villanoy C  Cabrera O 《Marine pollution bulletin》2011,63(5-12):195-200

Submarine groundwater discharge (SGD) on the reef flat of Bolinao, Pangasinan (Philippines) was mapped using electrical resistivity, 222Rn, and nutrient concentration measurements. Nitrate levels as high as 126 μM, or 1-2 orders of magnitude higher than ambient concentrations, were measured in some areas of the reef flat. Nutrient fluxes were higher during the wet season (May-October) than the dry season (November-April). Dissolved inorganic nitrogen (DIN=NO3+NO2+NH4) and soluble reactive phosphorus (SRP) fluxes during the wet season were 4.4 and 0.2 mmoles m(-2) d(-1), respectively. With the increase population size and anthropogenic activities in Bolinao, an enhancement of SGD-derived nitrogen levels is likely. This could lead to eutrophic conditions in the otherwise oligotrophic waters surrounding the Santiago reef flat.  相似文献   

Background levels and baseline values of available heavy metals in Mediterranean greenhouse soils (Spain)   总被引：2，自引：0，他引：2  

J.J. Ramos-Miras  L. Roca-Perez  M. Guzmán-Palomino  R. Boluda  C. Gil 《Journal of Geochemical Exploration》2011

This study determines extractable levels of Cd, Cu, Pb, Zn, Ni and Co in western Almería (Spain) greenhouse surface soil horizons using EDTA solution, which is identified as the fraction available for organisms and plants. It also establishes background levels, geochemical baseline concentration and reference values (RV), and investigates the possible relationships between soil properties and elemental concentrations. The results show that the soil concentration of these extractable heavy metals was high as those reported by other authors for Spanish agricultural soils. The available RV concentrations obtained (mg kg⁻¹) were: Cd 0.17, Cu 1.6, Pb 13.8, Zn 5.0 Ni 1.7 and Co 2.9. Using the upper baseline criterion, 95% of greenhouse soils present a relatively higher content of extractable heavy metals given their Cd and Cu concentration. Significant correlations between total and EDTA-extractable metal levels were found for Zn, Pb, Cu, Cd and Ni. Soil properties also related to heavy metals content, suggesting that Cd, Cu, Pb and Zn are of similar origin and relate to anthropic activities, and implies the same interactions and/or relationships among these metals.  相似文献   

Cme Phenomenology in Different Solar Magnetic Scenarios     

R. Rodríguez Taboada  G. Gil Moreno  A. Méndez Berhondo  R. Pérez-Enriquez 《Astrophysics and Space Science》1997,256(1-2):373-376

The existence of three magnetic scenarios with magnetic field intensities one order apart was considered. CMEs were associated to different solar activity phenomena and solar features showing different characteristics. Those associated to intense magnetic fields were more complex, having either more components or multiple emissions and a greater magnetic energy to particle acceleration conversion rate. On the other hand, simple CMEs were found to associate to weak magnetic fields. No evidence was found that the process that leads to CME starts before their detection at 1.6 solar radii. This indicates that the whole volume moves upward simultaneously, no matter how deep it reaches into the solar atmosphere.  相似文献   

Paucity of candidate coastal constructional landforms along proposed shorelines on Mars: Implications for a northern lowlands-filling ocean     

Gil J. Ghatan  James R. Zimbelman 《Icarus》2006,185(1):171-196

The case for an ocean having once occupied the northern lowlands of Mars has largely been based indirectly on the debouching of the outflow channels into the lowlands, and directly on erosional features along the margins of the lowlands interpreted to be the result of wave action. Two global shorelines were previously mapped from albedo variation, embayment relationships, and scarps interpreted as coastal cliffs. However, not since the early, Viking-based studies, has there been a focused assessment of the presence or absence of coastal constructional landforms such as barrier ridges and spits, located on or near the mapped “shorelines.” Such constructional landforms are typically found in association with coastal erosional features on Earth, and therefore warrant a detailed search for their presence on Mars. All presently available THEMIS VIS and MOC NA images located on or near either of the two “shorelines,” within the Chryse Planitia/Arabia Terra region (10° to 44° N; 300° to 0° E) and the Isidis Planitia region (0° to 30° N; 70° to 105° E), were examined in search of any features that could reasonably be considered candidate coastal ridges. Additionally, raw MOLA profiles were used in conjunction with a technique developed from Differential Global Positioning System profiles across terrestrial paleo-shorelines, to search for coastal ridges throughout these same regions. Out of 447 THEMIS VIS and 735 MOC NA images examined, only four candidates are observed that are plausibly interpreted as coastal ridges; no candidate coastal ridges are observed in the MOLA profiles. This overwhelming paucity of candidate features suggests one of five possible scenarios in terms of the existence of standing bodies of water within the martian lowlands: (1) No ocean existed up to the level of either of the previously mapped “shorelines”; (2) An ocean existed, however wave action, the primary agent responsible for construction of coastal landforms, was minimal to non-existent; (3) An ocean existed, but sediment input was not significant enough to form coastal deposits; (4) An ocean existed, but readily froze, and over time sublimated; and lastly (5) An ocean existed and coastal landforms were constructed, but in the intervening time since their formation they have nearly all been eroded away.  相似文献   

Responses of B-esterase enzymes in oysters (Crassostrea gigas) transplanted to pesticide contaminated bays form the Ebro Delta (NE,Spain)     

Victoria Ochoa  Carmen Riva  Melissa Faria  Carlos Barata 《Marine pollution bulletin》2013,66(1-2):135-142

Marine bivalves such as oysters are widely used as bioindicators to monitor marine coastal pollution. This study aimed to use B-esterase activity responses in oysters (Crassostrea gigas) cultured in Ebro Delta bays to monitor environmental effects of pesticides. The B esterases investigated were acetylcholinesterase, propionylcholinesterase, and carboxylesterase and their activities were measured in adductor muscle and gills from oysters transplanted in Ebro Delta bays where the are traditionally grown. Enzyme activities were related with physico-chemical parameters and pesticide levels measured in water. Cholinesterase activities measured in gills were unaffected across sites and periods. Conversely, carboxylesterase activities in oyster gills varied across periods and sites and were negatively correlated with residue levels of organophoshporous and carbamate pesticides in water. Therefore, inhibition of carboxylesterase activities can be considered a good indicator of exposure to anti-cholinergic pesticides in oysters.  相似文献   

Factors influencing magnetic susceptibility in the southern Pyrenees     

Óscar Pueyo Anchuela  Andrés J. Pocoví  Andrés Gil Imaz  Antonio M. Casas-Sainz 《Studia Geophysica et Geodaetica》2013,57(4):692-709

We analyse paramagnetic, ferrimagnetic and frequency-dependent susceptibility in the southern Pyrenees and northern Ebro basin. The analyzed rocks show a wide range of values for the three parameters within the different lithological groups. Sandstones, shales and marls exhibit middle to high values of paramagnetic susceptibility while mudstones usually show low values. However, a general correlation can be established for the different rock types with a wide variability for each group (for example, Eocene marls show average values of paramagnetic susceptibility of 82% but within a range between 12 and 99%, or Flysch materials, with mean values of 47–52% within a range between 15 and 90%). These changes in the paramagnetic contribution to the susceptibility are due to the change in the ferrimagnetic susceptibility. This wide variability is independent of the sedimentological characteristics and can be related to the higher ferrimagnetic contribution to the susceptibility with similar ferrimagnetic mineral phase assemblages. The ferrimagnetic and superparamagnetic contributions, independent of site location with respect to individual macrostructures (thrusts and nappes), show a sharp increase at the occurrence of the macroscopic regional Pyrenean cleavage, probably relating both aspects with changes in pressure-temperature (P-T) conditions.  相似文献   

Variabilité climatique et production de maïs en culture pluviale dans l'est Ivoirien     

Dabissi Noufé  Gil Mahé  Eric Servat 《水文科学杂志》2013,58(1):152-167

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Multi-proxy Stratigraphy and Paleoceanographic Variations in Sediment from the Korea Plateau,East Sea (Japan Sea), Over the Last 500 kyr     

Hyun  Sangmin  Kim  Jin-Kyung  Kang  Jeongwon  Kim  Gil Young 《Ocean Science Journal》2022,57(3):420-435

Ocean Science Journal - High-resolution geochemical measurements were performed on core E09-08, which was taken from the top flat area of the Korea Plateau in the East Sea (Japan Sea). Based on...  相似文献   

Lithological and structural prerequisites for localization of ore deposits in the Mesoproterozoic-Neoproterozoic Uchur-Maya depression (Siberian Platform)     

M. V. Goroshko  G. Z. Gil’manova 《Russian Journal of Pacific Geology》2013,7(4):262-276

A set of sketch maps has been compiled including a structural map for the Uchur-Maya depression, maps of the fractures based on the data derived from the digital elevation model processed using the modulus of the topographic gradient for discriminating the fault boundaries, and maps of the lineament distribution and the density of the elementary linear structures. On these sketch maps, the location of the ore deposits and the occurrences of various metals are plotted within the bounds of the Uchur-Maya depression with the defining structural and lithological factors that control the ore occurrences. The locations of the ore objects relative to the differently oriented faults and the lineament network based on the data of the digital elevation model’s processing and the density of the linear structures have been analyzed. The most important lithological factors that control the ore deposits are the pre-Mesoproterozoic structural-stratigraphic unconformity zones, the contact zones between the Mesoproterozoic formations with their contrasting physical and chemical properties, and the high-porosity (cavernous) dolomite member in the Yudomian Group of the Vendian.  相似文献   

Reductive dechlorination of polychlorinated biphenyls (PCBs) by ultrasound-assisted chemical process (UACP)     

J. R. Chen  Daeik Kim  Joon-Seok Park  Kyung-Ik Gil  Teh Fu Yen 《Environmental Earth Sciences》2013,69(3):1025-1032

The dechlorination of aqueous polychlorinated biphenyls (PCBs) using the ultrasound-assisted chemical process (UACP), which is a combination of ultrasonic irradiation and radical generations using di-tert-butyl peroxide as a radical initiator and ferrous ion as a catalyst at moderate temperature in alkaline 2-propanol, was demonstrated with a high reduction of PCBs. A commercial PCB-containing compound, Aroclor 1260, was also decomposed with the removal efficiency of 97 % achieved within 3 h of UACP. The gas chromatograph was used as a quantitative method to measure the decomposition rate of PCBs. The competitive elimination among the ortho (2-position), meta (3-position), and para (4-position) chlorine atoms of PCB was also identified.  相似文献