scholarly journals Sharks, rays and chimaeras of the Seine and Unicorn seamounts (NE Atlantic Ocean)

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Mafalda FREITAS ◽  
Ricardo SOUSA ◽  
Pedro IDEIA ◽  
Madalena GASPAR ◽  
João DELGADO ◽  
...  
Keyword(s):  
Biological Effects ◽  
Fish Fauna ◽  
Ne Atlantic ◽  
Valuable Contribution ◽  
Sea Floor ◽  
Madeira Archipelago ◽  
Geological Features ◽  
Ne Atlantic Ocean ◽  
Seamount Chain ◽  
First Time

Abstract Background Seamounts are underwater mountains which typically rise rather steeply at least several hundred meters above the deep-sea floor. These geological features interrupt water flow and hence may induce changes in the circulation of different water masses, in turn causing different physical and biological effects. For this reason, seamounts are biodiversity hotspots, housing a wide number of species, as is with the case of the Seine and Unicorn seamounts, which are a part of the Madeira-Tore seamount chain located between Portugal mainland, southwestern Europe and Madeira archipelago (NE Atlantic). Methods Fisheries independent surveys allowed the collection of Chondrichthyes specimens from the Seine and Unicorn seamounts. Individuals were caught over the course of two research cruises, first in 2004 and later in 2017, with species distribution ranging from the summit down to 2500 m of depth. Results Fifteen species belonging to 7 different taxonomical families were collected in the two surveyed areas. Two species were recorded for the first time and added to the checklist of the Seine seamount (Centrophorus granulosus and Somniosus rostratus), and three species for the Unicorn seamount (C. granulosus, Centroscymnus coelolepis and Centroselachus crepidater). Distribution and frequency of occurrence for the collected species were evaluated in relation to depth. Conclusions This work is a valuable contribution to the knowledge of seamount-associated fish fauna. Moreover, the checklist of sharks, rays and chimaeras was updated for the Seine and Unicorn seamounts, summing up 20 species.

Icelandia

2021 ◽  
Author(s):  
Gillian Foulger ◽  
Laurent Gernigon ◽  
Laurent Geoffroy
Keyword(s):  
Continental Crust ◽  
Structural Complexity ◽  
Ne Atlantic ◽  
Sea Floor ◽  
Passive Margins ◽  
The North ◽  
The Pacific ◽  
Ne Atlantic Ocean ◽  
Sea Floor Spreading ◽  
North And South

<p>The NE Atlantic formed by complex, piecemeal breakup of Pangea in an environment of structural complexity. North of the present-day latitude of Iceland the ocean opened by southward propagation of the Aegir ridge. South of the present-day latitude of Iceland breakup occurred along the proto-Reykjanes ridge which formed laterally offset by ~ 100 km from the Aegir ridge to the north. Neither of these new breakup axes were able to propagate across the east-westerly striking Caledonian frontal thrust region which formed a strong barrier ~ 400 km wide. As a result, while sea-floor spreading widened the NE Atlantic, the Caledonian front region could only keep pace by diffuse stretching of the continental crust, which formed the aseismic Greenland-Iceland-Faroe ridge. The magmatic rate there was similar to that of the ridges to the north and south and so the stretched continental crust is now blanketed by thick mafic flows and intrusions. The NE Atlantic also contains a magma-inflated microcontinent – the Jan Mayen Microplate Complex, and an unknown but probably large amount of stretched continental crust blanketed by seaward-dipping reflectors in the passive margins of Norway and Greenland. The NE Atlantic thus contains voluminous continental crust in diverse forms and settings. If even a small portion of the sunken continental material contiguous with the Greenland-Iceland-Faroe ridge is included the area exceeds a million square kilometers, an arbitrary threshold suggested to designate a sunken continent. We have called this region Icelandia. The conditions and processes that funneled large quantities of continental crust into the NE Atlantic ocean are common elsewhere. This includes much of the North and South Atlantic oceans including both the seaboards and the deep oceans. Nor are such processes and outcomes confined to oceans bordered by passive margins. They are also found around the Pacific rims where subduction is in progress. Indeed, these conditions and processes likely are generic to essentially all the world's oceans and are potentially also informed by observations from intracontinental extensional regions and land-locked seas.</p>

Characterization and evolution of spearfishing in Madeira archipelago, Eastern Atlantic

2020 ◽  
Vol 33 ◽  
pp. 15
Author(s):  
Roi Martínez-Escauriaza ◽  
Claudio Vieira ◽  
Lídia Gouveia ◽  
Nuno Gouveia ◽  
Margarida Hermida
Keyword(s):  
Fish Species ◽  
Young Men ◽  
Coastal Areas ◽  
Teleost Fishes ◽  
The North ◽  
Southeast Coast ◽  
Madeira Archipelago ◽  
First Time

Data obtained from licenses of spearfishers and surveys conducted in 2004 and 2017 allowed for the analysis, for the first time, of the practice of spearfishing in the Madeira archipelago. Only a small percentage of the population practices spearfishing, mostly local young men. Most of them practice the activity with a partner throughout most of the year and along most of the island's coastal areas, although preferentially along the North and Southeast coast. Results show how, in recent years, despite the population of spearfishers decreasing, the abundance in the annual catch potentially increased, probably due to the higher investment of time in this activity. It has been observed that many fishers complement their catches with manual collecting of invertebrates. Overall, 40 teleost fishes and also 4 crustaceans and 8 molluscs were identified. The most frequently captured fish species were parrotfish and white seabream, while limpets were the most collected invertebrates in both selected periods.

scholarly journals OAM light propagation through tissue

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Netanel Biton ◽  
Judy Kupferman ◽  
Shlomi Arnon
Keyword(s):  
Light Propagation ◽  
Biological Imaging ◽  
Gaussian Beams ◽  
Medical Implants ◽  
Optical Wireless ◽  
Scattering Media ◽  
Valuable Contribution ◽  
Light Beams ◽  
First Time ◽  
Diffuse Media

AbstractA major challenge in use of the optical spectrum for communication and imaging applications is the scattering of light as it passes through diffuse media. Recent studies indicate that light beams with orbital angular momentum (OAM) can penetrate deeper through diffuse media than simple Gaussian beams. To the best knowledge of the authors, in this paper we describe for the first time an experiment examining transmission of OAM beams through biological tissue with thickness of up to a few centimeters, and for OAM modes reaching up to 20. Our results indicate that OAM beams do indeed show a higher transmittance relative to Gaussian beams, and that the greater the OAM, the higher the transmittance also up to 20, Our results extend measured results to highly multi scattering media and indicate that at 2.6 cm tissue thickness for OAM of order 20, we measure nearly 30% more power in comparison to a Gaussian beam. In addition, we develop a mathematical model describing the improved permeability. This work shows that OAM beams can be a valuable contribution to optical wireless communication (OWC) for medical implants, optical biological imaging, as well as recent innovative applications of medical diagnosis.

scholarly journals Kilometre-scale polygonal seabed depressions in the Hatton Basin, NE Atlantic Ocean: Constraints on the origin of polygonal faulting

2012 ◽  
Vol 332-334 ◽  
pp. 126-133 ◽  
Author(s):  
Christian Berndt ◽  
Colin Jacobs ◽  
Alan Evans ◽  
Aurélien Gay ◽  
Gavin Elliott ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
Ne Atlantic ◽  
Ne Atlantic Ocean

scholarly journals The fish fauna of Ampère Seamount (NE Atlantic) and the adjacent abyssal plain

2014 ◽  
Vol 69 (1) ◽  
pp. 13-23 ◽  
Author(s):  
Bernd Christiansen ◽  
Rui P. Vieira ◽  
Sabine Christiansen ◽  
Anneke Denda ◽  
Frederico Oliveira ◽  
...  
Keyword(s):  
Fish Fauna ◽  
Abyssal Plain ◽  
Ne Atlantic

scholarly journals The fishes of the Bolaman Stream, Northern Turkey

2021 ◽  
Vol 4 (1) ◽  
pp. 38-54
Author(s):  
Serkan Saygun
Keyword(s):  
Black Sea ◽  
Fish Species ◽  
Fish Fauna ◽  
The Black Sea ◽  
Fish Samples ◽  
First Time ◽  
Squalius Cephalus

In this study, the fish species inhabiting the Bolaman Stream drains to the Black Sea from the Fatsa coast (Ordu Province, Turkey) was reported for the first time. The study was caught out non-periodically by sampling from seven stations in the Bolaman Stream between July 2017 and November 2018. Fish samples were captured with an electroshock device. With this study, it was determined that the fish fauna of the Bolaman Stream is represented by 10 species in five families (Acheilognothidae, Cyprinidae, Gobiidae, Leuciscidae, and Salmonidae). These species were as follows, respectively Rhodeus amarus, Barbus tauricus, Capoeta banarescui, Neogobius fluviatilis, Ponticola turani, Alburnus derjugini, Squalius cephalus, Vimba vimba, Alburnoides fasciatus, and Salmo coruhensis.

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