scholarly journals A Model of Fish Behavior Towards a Water Bottom with a Gradient.

1997 ◽  
Vol 63 (1) ◽  
pp. 35-42
Author(s):  
Zhenlin Liang ◽  
Ko Matuda ◽  
Tadashi Tokai
Keyword(s):  
Author(s):  
Truong Van Tuan ◽  
Irina Vladimirovna Volkova

Research was held in the estuary of the river Bach Dang (Dongbay community, Rakhtay district, Hai Phong, Vietnam) in June, 2012 - May, 2013. Concentration of lead was studied in water, suspended solids and bottom sediment. Clam beach (natural breeding environment of Meretrix lyrata ) was inspected regularly, every month. Water samples were taken 6 times from the bottom layer 10 cm down the bottom, once per 3 hours in each of 12 investigated zones. Bottom sediment samples were taken at the depth 2 cm. The findings show that lead accumulates mainly in suspended solids (23.3 mg/kg) and in bottom sediment (14.31 mg/kg), in water it is in small quantities (0.003 mg/kg). Analysis of bottom sediment samples taken in different places showed that they have even leadcontent, lead is distributed uniformly, localization of contaminations is not found. The results obtained can be assumed as the basis for investigating lead accumulation and its excretion by clam Meretrix lyrata organisms in the natural habitat.


Author(s):  
Ngo The Cuong ◽  
Tran Hoan Quoc ◽  
Svetlana Vasilievna Zolotokopova

The article focuses on the study of change of containing heavy metals (zinc, copper, iron, cadmium, lead, arsenic) in the abiotic and biotic components of the Serepok river (Vietman) influenced by wastewater discharge from industrial areas. Heavy metal content was determined in the river water and bottom sediments in the four zones: above and within the boundaries of industrial regions Xoa Phu and Tam Thang and in two water reservoirs situated below the boundaries of those industrial areas. Tilapia Galilean ( Sarotherodon galilaeus ), Hemibagrus ( Hemibagrus ), and sazan ( Cyprinus carpio ) caught in these areas were the hydrobionts under study in which liver, gills, skeleton and muscles accumulation of heavy metals was detected. In the organs of fish caught in the river within industrial region, heavy metals concentration was 3-7 times higher. The greatest concentration of heavy metals was found in the liver and gills of fish caught in the boundaries of industrial regions, the least concentration was in the muscles. In most cases, significant correlation between heavy metal concentration in organs of fishes and in river water, bottom sediments has been revealed.


Author(s):  
Preeti Rajput ◽  
Ratheesh Ramakrishnan ◽  
Shincy Francis ◽  
A.V. Thomaskutty ◽  
Ritesh Agrawal ◽  
...  
Keyword(s):  
Sar Data ◽  

Geophysics ◽  
1983 ◽  
Vol 48 (7) ◽  
pp. 854-886 ◽  
Author(s):  
Ken Larner ◽  
Ron Chambers ◽  
Mai Yang ◽  
Walt Lynn ◽  
Willon Wai

Despite significant advances in marine streamer design, seismic data are often plagued by coherent noise having approximately linear moveout across stacked sections. With an understanding of the characteristics that distinguish such noise from signal, we can decide which noise‐suppression techniques to use and at what stages to apply them in acquisition and processing. Three general mechanisms that might produce such noise patterns on stacked sections are examined: direct and trapped waves that propagate outward from the seismic source, cable motion caused by the tugging action of the boat and tail buoy, and scattered energy from irregularities in the water bottom and sub‐bottom. Depending upon the mechanism, entirely different noise patterns can be observed on shot profiles and common‐midpoint (CMP) gathers; these patterns can be diagnostic of the dominant mechanism in a given set of data. Field data from Canada and Alaska suggest that the dominant noise is from waves scattered within the shallow sub‐buttom. This type of noise, while not obvious on the shot records, is actually enhanced by CMP stacking. Moreover, this noise is not confined to marine data; it can be as strong as surface wave noise on stacked land seismic data as well. Of the many processing tools available, moveout filtering is best for suppressing the noise while preserving signal. Since the scattered noise does not exhibit a linear moveout pattern on CMP‐sorted gathers, moveout filtering must be applied either to traces within shot records and common‐receiver gathers or to stacked traces. Our data example demonstrates that although it is more costly, moveout filtering of the unstacked data is particularly effective because it conditions the data for the critical data‐dependent processing steps of predictive deconvolution and velocity analysis.


2014 ◽  
Vol 32 (2) ◽  
pp. 140-143 ◽  
Author(s):  
C. A. Layman ◽  
Z. R. Jud ◽  
D. Albrey Arrington ◽  
D. Sabin

Author(s):  
Takero Yoshida ◽  
Daigo Furuichi ◽  
Benjamin J. Williamson ◽  
Jinxin Zhou ◽  
Shuchuang Dong ◽  
...  

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