Genetic history of the population of Atlantic salmon, Salmo salar L., under restoration in the Connecticut River, USA     

Ayllon  Fernando; Martinez  Jose L.; Juanes  Francis; Gephard  Stephen; Garcia-Vazquez  Eva 《ICES Journal of Marine Science》2006,63(7):1286-1289

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Constraining the origin and evolution of confined turbidite systems: southern Cretan margin,Eastern Mediterranean Sea (34°30–36°N)     

Tiago M. Alves  Vasilios Lykousis  Dimitris Sakellariou  Stamatina Alexandri  Paraskevi Nomikou 《Geo-Marine Letters》2007,27(1):41-61

Bathymetric, 9.5-kHz long-range sidescan sonar (OKEAN), seismic reflection and sediment-core data are used in the analysis of two tectonic troughs south of Crete, Eastern Mediterranean Sea. Here, up to 1.2 s two-way travel time (TWTT) of strata have accumulated since the Middle Miocene in association with extension in the South Aegean region. The study area comprises >100-km- long by >25-km-wide basins filled by sediments subdivided into two seismic units: (1) an upper Unit 1 deposited in sub-basins which follow the present-day configuration of the southern Cretan margin; (2) a basal Unit 2, more than 500 ms (TWTT) thick, accumulated in deeper half-graben/grabens distinct from the present-day depocentres. Both units overlap a locally stratified Unit 3 comprising the pre-Neogene core complex of Crete and Gavdos. In this work, the interpreted seismic units are correlated with the onshore stratigraphy, demonstrating that denudation processes occurring on Crete and Gavdos in response to major tectonic events have been responsible for high sedimentation rates along the proximal southern Cretan margin. Consequently, topographically confined sedimentary units have been deposited south of Crete in the last 12 Ma, including turbidites and other mass-flow deposits fed by evolving transverse and axial channel systems. Surface processes controlling facies distribution include the direct inflow of sediment from alluvial-fan systems and incising mountain rivers onto the Cretan slope, where significant sediment instability processes occur at present. In this setting, seismic profiles reveal eight different types of stratigraphic contacts on basin-margin highs, and basinal areas show evidence of halokinesis and/or fluid escape. The acquired data also show that significant changes to the margin’s configuration occurred in association with the post-Alpine tectonic and eustatic episodes affecting the Eastern Mediterranean.  相似文献   

Genetic identification of hake and megrim eggs in formaldehyde-fixed plankton samples   总被引：4，自引：0，他引：4  

Perez  Juliana; Alvarez  Paula; Martinez  Jose L.; Garcia-Vazquez  Eva 《ICES Journal of Marine Science》2005,62(5):908-914

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The dynamics of the carbon cycle in the surface water of the Norwegian Sea     

Eva Falck  Leif G. Anderson   《Marine Chemistry》2005,94(1-4):43

Historical data of total dissolved inorganic carbon (C_T), together with nitrate and phosphate, have been used to model the evolution of these constituents over the year in the Atlantic water of the Norwegian Sea. Changes in nutrient concentration in the upper layer of the ocean are largely related to biological activity, but vertical mixing with the underlying water will also have an impact. A mixing factor is estimated and used to compute the entrainment of these constituents into the surface water from below. After taking the mixing contribution into account, the resulting nutrient concentration changes are attributed to biological production or decay. The results of the model show that the change in C_T by vertical mixing and by biological activity based on nutrient equivalents needs another sink to balance the carbon budget. It cannot be the atmosphere as the surface water is undersaturated with respect to carbon dioxide and is, thus, a source of C_T in this region. Inasmuch as the peak deficit of carbon is more than a month later than for the nutrients, the most plausible explanation is that other nitrogen and phosphate sources than the inorganic salts are used together with dissolved inorganic carbon during this period. As nitrate and phosphate show a similar trend, it is unlikely that the explanation is the use of ammonia or nitrogen fixation but rather dissolved organic nitrogen and phosphate, while dissolved organic carbon is accumulating in the water.  相似文献   

The humin structure of mucilage aggregates in the Adriatic and Tyrrhenian seas: hypothesis about the reasonable causes of mucilage formation     

Mauro Mecozzi  Eva Pietrantonio  Vito Di Noto  Zsuzsa Ppai 《Marine Chemistry》2005,95(3-4):255-269

Sixteen mucilages sampled in the Adriatic and Tyrrhenian seas during 1999–2001 were characterised using spectroscopic [Fourier transform infrared spectroscopy (FTIR); colorimetric], chromatographic [thin-layer chromatography (TLC)], and elemental analysis techniques. Most samples contained comparable fractions of organic and inorganic compounds, with the exception of a few samples where the inorganic fraction was greater than the organic fraction. Carbohydrates were important in the samples rich in organic matter, while carbonate and silica (quartz and biogenic silica) were the most important constituents of the inorganic fraction. Carbonate and silica were the only important constituents of the samples with a very low organic content.According to chemical analyses, mucilage aggregates show the typical structure of humin—the insoluble fraction of the humic substance. Classification of mucilage samples as humin-like compounds, together with a reexamination of the factors involved in the formation of organic aggregates in marine environment, has led to the formulation of a reasonable hypothesis for mucilage formation.  相似文献   

Respiration of Dry Cysts of Artemia Sauna L     

Sundnes  Gunnar; Valen  Eva 《ICES Journal of Marine Science》1969,32(3):413-415

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Litho-asthenospheric structures of northern Italy as inferred from teleseismic P-wave tomography     

S. Solarino  D. Spallarossa  S. Parolai  M. Cattaneo  C. Eva 《Tectonophysics》1996,260(4):271-289

Regional three-dimensional inversions of teleseismic P-wave travel time residuals recorded by high-frequency regional and local seismic networks operating along the Western Alps and surrounding regions were carried out and lithosphere and upper mantle P-wave velocity models down to 300 km were obtained.

Residuals of more than 500 teleseismic events, recorded by 98 fixed and temporary seismic stations, have been inverted.

The comparison between real residuals and the ones obtained from tomographic model indicates that the method is able to solve the feature of the regional heterogeneities.

Where the resolution is good, coherent lithospheric and upper mantle structures are imaged. In the shallower layers, high- and low-velocity anomalies follow the structural behaviour of the Alpine-Apenninic chains showing the existence of very strong velocity contrasts. In the deepest layers, velocity contrast decreases however two deep-seated high-velocity structures are observed. The most extended in depth and approximately trending NE-SW has been interpreted as a wreck of the oldest subduction responsible of the Alpine orogenesis. The second one, connected to the northwestern sector of the Apenninic chain, appears to vanish at depths greater than 180 km and is probably due to still active Apenninic roots.

Cross-sections depict the spatial trend of perturbations and in particular outline the sub-vertical character of the Alpine and Apenninic anomalies. Under the Ligurian Sea, the 3-D inversion confirms the uplift of the asthenosphere in agreement with the tectonic evolution of the basin.  相似文献   

Tentative study of flow patterns in the North Aegean Sea using NOAA-AVHRR images and 2D model simulation     

Zodiatis  G.  Alexandri  S.  Pavlakis  P.  Jonsson  L.  Kallos  G.  Demetropoulos  A.  Georgiou  G.  Theodorou  A.  Balopoulos  E. 《Annales Geophysicae》1997,14(11):1221-1231

A statistical technique for image processing, the maximum cross correlation (MCC) method, was utilized on sequences of NOAA-AVHRR thermal data in order to explore the surface advective current dynamics at the discharge region of the Hellespont in the North Aegean Sea. A 2D numerical flow model was also used in order to simulate the barotropic flow pattern of the surface water layer. The model was forced with diurnal wind fields obtained for the same period as the satellite infrared images. The currents (magnitude and direction) derived from the two methods compare satisfactorily despite the fact that some model simplifications were made.  相似文献   

Variographic analysis of tropical forest cover from multi-scale remotely sensed imagery     

Sergio Colombo  Mario Chica-Olmo  Francisco Abarca  Hugh Eva 《ISPRS Journal of Photogrammetry and Remote Sensing》2004,58(5-6):330-341

Tropical forest mapping is one of the major environmental concerns at global and regional scales in which remote sensing techniques are firmly involved. This study examines the use of the variogram function to analyse forest cover fragmentation at different image scales. Two main aspects are considered here: (1) analysis of the spatial variability structure of the forest cover observed at three different scales using fine, medium and coarse spatial resolution images; and (2) the study of the relationship between rescaled images from the finest spatial resolution and those of the medium and coarse spatial resolutions. Both aspects are analysed using the variogram function as a basic tool to calculate and interpret the spatial variability of the forest cover. An example is presented for a Brazilian tropical forest zone using satellite images of different spatial resolutions acquired by Landsat TM (30 m), Resurs MSU (160 m) and ERS ATSR (1000 m). The results of this study contribute to establishing a suitable spatial resolution of remotely sensed data for tropical forest cover monitoring.  相似文献   

Application of Distributed Temperature Sensing for coupled mapping of sedimentation processes and spatio‐temporal variability of groundwater discharge in soft‐bedded streams          下载免费PDF全文

Eva Sebok  Carlos Duque  Peter Engesgaard  Eva Boegh 《水文研究》2015,29(15):3408-3422

The delineation of groundwater discharge areas based on Distributed Temperature Sensing (DTS) data of the streambed can be difficult in soft‐bedded streams where sedimentation and scouring processes constantly change the position of the fibre optic cable relative to the streambed. Deposition‐induced temperature anomalies resemble the signal of groundwater discharge while scouring will cause the cable to float in the water column and measure stream water temperatures. DTS applied in a looped layout with nine fibre optic cable rows in a 70 × 5 m section of a soft‐bedded stream made it possible to detect variability in streambed temperatures between October 2011 and January 2012. Detailed monthly streambed elevation surveys were carried out to monitor the position of the fibre optic cable relative to the streambed and to quantify the effect of sedimentation processes on streambed temperatures. Based on the simultaneous interpretation of streambed temperature and elevation data, a method is proposed to delineate potential high‐groundwater discharge areas and identify deposition‐induced temperature anomalies in soft‐bedded streams. Potential high‐discharge sites were detected using as metrics the daily minimum, maximum and mean streambed temperatures as well as the daily amplitude and standard deviation of temperatures. The identified potential high‐discharge areas were mostly located near the channel banks, also showing temporal variability because of the scouring and redistribution of streambed sediments, leading to the relocation of pool‐riffle sequences. This study also shows that sediment deposits of 0.1 m thickness already resulted in an increase in daily minimum streambed temperatures and decrease in daily amplitude and standard deviation. Scouring sites showed lower daily minimum streambed temperatures and higher daily amplitude and standard deviation compared with areas without sedimentation and scouring. As a limitation of the approach, groundwater discharge occurring at depositional and scouring areas cannot be identified by the metrics applied. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献