On the Productivity of the Southwest Atlantic Ocean and the Waters West of the Antarctic Peninsula

Author(s):  
Sayed Z. El-Sayed
2020 ◽  
Vol 21 (1) ◽  
pp. 135-140
Author(s):  
Eduardo Juri ◽  
Meica Valdivia ◽  
Paulo Cesar Simoes-Lopes ◽  
Alfredo Le Bas

The minke whale is the smallest of the living rorquals and is widely distributed in the tropical, temperate and polar waters of both hemispheres. In the western Southwest Atlantic Ocean there are two currently recognised species, the dwarf form of the common minke whale, Balaenoptera acutorostrata unnamed subsp. and the Antarctic minke whale B. bonaerensis. All stranding records and collected specimens of minke whale on the coast of Uruguay were reviewed and analysed. Between 1962 and 2018, 33 records were gathered in a non-systematic way, 22 specimens of B. acutorostrata and 11 of B. bonaerensis. It was found that most animals were discovered alive or recently dead and assigned as neonates/young calves. This supports the hypothesis that Uruguayan coasts are part of an important region for reproduction and breeding for the species.


1991 ◽  
Vol 65 (03) ◽  
pp. 396-411 ◽  
Author(s):  
Michael R. Sandy

Articulate brachiopods from the Aptian–Coniacian (Kotick Point and Whisky Bay Formations, Gustav Group) and the Santonian–Campanian (Santa Marta Formation, Marambio Group) of James Ross Island are described. A new terebratulid species,Rectithyris whiskyin. sp., is described from the late Albian–early Coniacian of the Whisky Bay Formation. The record from the late Albian is supported by palynological evidence making it contemporaneous with other species ofRectithyrisfrom Europe. The relative abundance ofRectithyris whiskyin. sp. in late Turonian to early Coniacian sections indicates an extended biohorizon that may aid biostratigraphic correlation in the James Ross Island region.The brachiopods have some affinities with faunas described from Europe, northern Siberia, North America, Madagascar, southern India, Western Australia, and Alexander Island, Antarctic Peninsula. Elements of the James Ross Island brachiopod fauna probably migrated by the following routes: 1) from northern high latitudes via the Eastern Pacific; 2) from Europe via the north and central Atlantic and opening south Atlantic Ocean; and 3) via Eastern Tethys, the East African Seaway, to the south Atlantic Ocean. Brachiopod evidence supports a fully marine connection between the central Atlantic and south Atlantic Ocean (Route 2) possibly as early as the late Albian (as do ammonite faunas from western Africa), and certainly by the late Turonian. Route 3 was established in the Cretaceous by the Aptian?–Albian to eastern Africa and Madagascar and to the Antarctic Peninsula by the late Turonian. Faunal links between James Ross Island and Western Australia support the Late Cretaceous juxtaposition of these plates.A distinct austral brachiopod fauna may be present in the Cretaceous from the Aptian onwards (although current evidence is scant). Antarctic Peninsular and Western Australian faunas yield five brachiopod genera (and their species) endemic to Gondwanaland's southern marine fauna. Other genera known from the Antarctic Peninsula (Kingena, Ptilorhynchia, andRectithyris) and the Northern Hemisphere may have species endemic to Gondwanaland.


Nature ◽  
2014 ◽  
Vol 505 (7484) ◽  
pp. 538-542 ◽  
Author(s):  
Xichen Li ◽  
David M. Holland ◽  
Edwin P. Gerber ◽  
Changhyun Yoo

2016 ◽  
Vol 29 (17) ◽  
pp. 6109-6125 ◽  
Author(s):  
Damien Irving ◽  
Ian Simmonds

Abstract The Pacific–South American (PSA) pattern is an important mode of climate variability in the mid-to-high southern latitudes. It is widely recognized as the primary mechanism by which El Niño–Southern Oscillation (ENSO) influences the southeast Pacific and southwest Atlantic and in recent years has also been suggested as a mechanism by which longer-term tropical sea surface temperature trends can influence the Antarctic climate. This study presents a novel methodology for objectively identifying the PSA pattern. By rotating the global coordinate system such that the equator (a great circle) traces the approximate path of the pattern, the identification algorithm utilizes Fourier analysis as opposed to a traditional empirical orthogonal function approach. The climatology arising from the application of this method to ERA-Interim reanalysis data reveals that the PSA pattern has a strong influence on temperature and precipitation variability over West Antarctica and the Antarctic Peninsula and on sea ice variability in the adjacent Amundsen, Bellingshausen, and Weddell Seas. Identified seasonal trends toward the negative phase of the PSA pattern are consistent with warming observed over the Antarctic Peninsula during autumn, but are inconsistent with observed winter warming over West Antarctica. Only a weak relationship is identified between the PSA pattern and ENSO, which suggests that the pattern might be better conceptualized as a preferred regional atmospheric response to various external (and internal) forcings.


2020 ◽  
Vol 30 (3) ◽  
pp. 426-439 ◽  
Author(s):  
Laura Schejter ◽  
Gabriel Genzano ◽  
Esteban Gaitán ◽  
Carlos D. Perez ◽  
Claudia S. Bremec

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