scholarly journals Ecological studies of the Russian exploration area on the Mid-Atlantic ridge on the 39th cruise of RV Professor Logachev

2019 ◽  
Vol 59 (4) ◽  
pp. 684-686
Author(s):  
S. V. Galkin ◽  
T. N. Molodtsova ◽  
K. V. Minin ◽  
S. G. Kobyliansky
Keyword(s):  
Benthic Communities ◽  
Ecological Studies ◽  
Composition And Structure ◽  
Mid Atlantic Ridge ◽  
Exploration Area

During the 39th cruise of RV Professor Logachev ecological studies of the Russian exploration area in the Central part of the Northern Mid-Atlantic Ridge were conducted. New data on the composition and structure of benthic communities as well as composition and distribution of ichthyofauna were obtained.

Ecological Studies of the Russian Exploration Area on the Mid-Atlantic Ridge on the 39th Cruise of RV Professor Logachev

Oceanology ◽  
2019 ◽  
Vol 59 (4) ◽  
pp. 616-617 ◽  
Author(s):  
S. V. Galkin ◽  
T. N. Molodtsova ◽  
K. V. Minin ◽  
S. G. Kobyliansky
Keyword(s):  
Ecological Studies ◽  
Mid Atlantic Ridge ◽  
Exploration Area

AN OIL SPILL IN AN ILLINOIS LAKE: ECOLOGICAL AND HUMAN HEALTH ASSESSMENT

1995 ◽  
Vol 1995 (1) ◽  
pp. 415-420 ◽  
Author(s):  
Jerry Neff ◽  
Ted Sauer ◽  
Lewis Osborn ◽  
Pamela Tazik ◽  
Lawrence Reitsema
Keyword(s):  
Largemouth Bass ◽  
Benthic Communities ◽  
Health Assessment ◽  
Late Summer ◽  
Complete Recovery ◽  
Ecological Studies ◽  
Insect Larvae ◽  
Edible Tissues ◽  
Power Plant Cooling

ABSTRACT Long-term ecological studies were initiated shortly after an April 1985 release of 452,550 gallons of a Southern Louisiana crude oil into a 1750-acre electric power plant cooling lake. Aquatic plants (macrophytes) in the most heavily oiled region of the lake were coated with oil and most had died by late summer 1986. Macrophytes from lightly oiled areas of the lake had nearly recovered by late summer 1986. Macrophytes in other parts of the lake were completely unaffected by the release of oil. A year after the release, diversity and abundance of bottom-living animals decreased in the most heavily oiled parts of the lake and previously dominant insect larvae were replaced by opportunistic oligochaetes. Complete recovery of the most severely affected benthic communities required four years in the deep parts of the lake and five years in shallow areas. There was a small kill of fish ($$200 fish) immediately after the release and a small decrease in the abundance of preferred recreational fish species (largemouth bass and white crappie) during the summer after the release. However, between 1986 and 1991, abundance of recreational fish in the lake was comparable to that before the accident. Fish did not accumulate sufficient PAH in edible tissues to pose a health risk to human consumers.

On the relationship between the diversity and structure of benthic macroinvertebrate communities and sediment enrichment with heavy metals in Gabes Gulf, Tunisia

2014 ◽  
Vol 95 (2) ◽  
pp. 233-245 ◽  
Author(s):  
Lotfi Rabaoui ◽  
Radhouane El Zrelli ◽  
Mohammed Ben Mansour ◽  
Rafik Balti ◽  
Lamjed Mansour ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Benthic Communities ◽  
Central Area ◽  
Macroinvertebrate Communities ◽  
Benthic Assemblages ◽  
Gulf Of Gabes ◽  
Gulf Of Gabès ◽  
Composition And Structure ◽  
Ecological Quality Status ◽  
The Relationship

The variations in the composition and structure of macroinvertebrate benthic communities in relationship with the marine sediment enrichment with heavy metals were investigated in the Gulf of Gabes, Tunisia. Standard community parameters as well as the trophic and ecological structure were analysed in 18 stations sampled in six localities. Highest values of diversity descriptors (S, N and H′) were recorded in the less-polluted localities and vice versa. Besides, the results of AMBI and BENTIX indexes were also concordant with those obtained with the classical diversity parameters and matched with the sediment heavy metals distribution in the Gulf of Gabes. Compared with the northern and southern parts of the Gulf, the central area was found to be the most polluted and to host the most-affected benthic community. In addition, biotic indexes were found to be very useful tools to monitor the ecological quality status of benthic assemblages.

Changes in benthic communities along a 0–60 m depth gradient in the remote St. Peter and St. Paul Archipelago (Mid-Atlantic Ridge, Brazil)

2015 ◽  
Vol 91 (3) ◽  
pp. 377-396 ◽  
Author(s):  
Gabriela Machado Magalhães ◽  
Gilberto Menezes Amado-Filho ◽  
Marcos Rogerio Rosa ◽  
Rodrigo Leão de Moura ◽  
Poliana Silva Brasileiro ◽  
...  
Keyword(s):  
Benthic Communities ◽  
Depth Gradient ◽  
Mid Atlantic Ridge

scholarly journals Studies of the ecosystems associated with hydrothermal vents and cold seeps in the Bering sea (82nd cruise of RV Akademik M.A. Lavrentyev)

2019 ◽  
Vol 59 (4) ◽  
pp. 687-690
Author(s):  
S. V. Galkin ◽  
V. V. Mordukhovich ◽  
E. M. Krylova ◽  
V. A. Denisov ◽  
A. N. Malutin ◽  
...  
Keyword(s):  
Bering Sea ◽  
Hydrothermal Vents ◽  
Benthic Communities ◽  
World Ocean ◽  
Cold Seep ◽  
Cold Seeps ◽  
Multidisciplinary Study ◽  
The Pacific ◽  
Composition And Structure ◽  
The Bering Sea

During the 82nd cruise of RV Akademik M. A. Lavrentyev a multidisciplinary study of the ecosystems associated with hydrothermal vents and cold seeps in the Bering Sea was conducted. New data on the composition and structure of benthic communities of the Piip's Volcano are obtained. On the Koryak slope of the Bering Sea, a new cold seep region was discovered. Chemosynthesis-based communities on the Koryak slope are the northern-most of their kind in the Pacific, and the Koryak population of Calyptogena is the northern-most Recent population of pliocardiines in the World Ocean.

scholarly journals The influence of fluids on the species composition and preservation of microfossils in biogenic carbonate sediments by hydrothermal cluster “Pobeda” (Mid-Atlantic ridge)

2019 ◽  
pp. 592-606
Author(s):  
I. F. Gablina ◽  
O. B. Dmitrenko ◽  
T. A. Khusid ◽  
N. V. Libina
Keyword(s):  
Species Composition ◽  
Hydrothermal Activity ◽  
Carbonate Content ◽  
Carbonate Sediments ◽  
Chemical Parameters ◽  
Composition Distribution ◽  
Physical Chemical ◽  
Number Of Microorganisms ◽  
Mid Atlantic Ridge ◽  
Exploration Area

The species composition, distribution and preservation of carbonate shells of nanno and microfossils of biogenic bottom sediments within the hydrothermal cluster Pobeda (1707.451708.7 n) were studied on the basis of materials obtained in flight No. 37 of NIS Professor Logachev in the Russian exploration area (Mid-Atlantic ridge). Physical-chemical parameters and the total carbonate content of sediments were measured, their changes in column sections were revealed. For complexes of coccoliths studied precipitation is attributed to the top (acme) biostratigraphic zone of Emiliania huxleyi. It is established that within the zone of hydrothermal activity (ore cluster Pobeda) the total number of microorganisms decreases and their species diversity decreases, as a rule, in the lower part of the columns. Down the column section also decreases the Eh, pH and carbonate precipitation. These changes are explained by the influence of diffuse hydrothermal fluids.

Crystal Structure Analysis of Cu-Zr Alloys by Convergent Beam Diffraction

1981 ◽  
Vol 39 ◽  
pp. 354-355
Author(s):  
A. F. Marshall ◽  
J. W. Steeds ◽  
D. Bouchet ◽  
S. L. Shinde ◽  
R. G. Walmsley
Keyword(s):  
Crystal Structure ◽  
Point Group ◽  
Intermetallic Phase ◽  
Three Dimensional ◽  
Crystal Structure Analysis ◽  
Ion Milling ◽  
Composition And Structure ◽  
Unit Cells ◽  
Sputter Deposited ◽  
Convergent Beam

Convergent beam electron diffraction is a powerful technique for determining the crystal structure of a material in TEM. In this paper we have applied it to the study of the intermetallic phases in the Cu-rich end of the Cu-Zr system. These phases are highly ordered. Their composition and structure has been previously studied by microprobe and x-ray diffraction with sometimes conflicting results.The crystalline phases were obtained by annealing amorphous sputter-deposited Cu-Zr. Specimens were thinned for TEM by ion milling and observed in a Philips EM 400. Due to the large unit cells involved, a small convergence angle of diffraction was used; however, the three-dimensional lattice and symmetry information of convergent beam microdiffraction patterns is still present. The results are as follows:1) 21 at% Zr in Cu: annealed at 500°C for 5 hours. An intermetallic phase, Cu3.6Zr (21.7% Zr), space group P6/m has been proposed near this composition (2). The major phase of our annealed material was hexagonal with a point group determined as 6/m.

Off-axis electron holography applied to the study of interfaces

1992 ◽  
Vol 50 (1) ◽  
pp. 244-245
Author(s):  
J.K. Weiss ◽  
M. Gajdardziska-Josifovska ◽  
M. R. McCartney ◽  
David J. Smith
Keyword(s):  
Electric Fields ◽  
Resolution Enhancement ◽  
Interfacial Structure ◽  
Atomic Scale ◽  
Bulk Property ◽  
Electron Holography ◽  
Specimen Thickness ◽  
Composition And Structure ◽  
Chemical Segregation ◽  
Diffraction Effects

Interfacial structure is a controlling parameter in the behavior of many materials. Electron microscopy methods are widely used for characterizing such features as interface abruptness and chemical segregation at interfaces. The problem for high resolution microscopy is to establish optimum imaging conditions for extracting this information. We have found that off-axis electron holography can provide useful information for the study of interfaces that is not easily obtained by other techniques.Electron holography permits the recovery of both the amplitude and the phase of the image wave. Recent studies have applied the information obtained from electron holograms to characterizing magnetic and electric fields in materials and also to atomic-scale resolution enhancement. The phase of an electron wave passing through a specimen is shifted by an amount which is proportional to the product of the specimen thickness and the projected electrostatic potential (ignoring magnetic fields and diffraction effects). If atomic-scale variations are ignored, the potential in the specimen is described by the mean inner potential, a bulk property sensitive to both composition and structure. For the study of interfaces, the specimen thickness is assumed to be approximately constant across the interface, so that the phase of the image wave will give a picture of mean inner potential across the interface.

Sign in / Sign up

Export Citation Format

Share Document