scholarly journals A numerical study of the Plata River plume along the southeastern South American continental shelf

2005 ◽  
Vol 53 (3-4) ◽  
pp. 129-146 ◽  
Author(s):  
Felipe M. Pimenta ◽  
Edmo José Dias Campos ◽  
Jerry L. Miller ◽  
Alberto R. Piola

The Rio de la Plata, one of the largest rivers on Earth, discharges into the ocean waters from basin that covers a large area of South America. Its plume extends along northern Argentina, Uruguay, and southern Brazil shelves strongly influencing the ecosystems. In spite of this, little is known about the mechanisms that control it. Here we report results of simulations with POM carried out to investigate the roles of wind and river discharge in Plata plume dynamics. Different outflows were explored, including an average climatological value and magnitudes representative of La Niña and El Niño. Forcing the model with river discharge the average plume speed was directly related to the outflow intensity. The Plata northward extension varied from 850 to 1550 km and for average discharge a band of low salinity waters formed from the estuary up to 30ºN of South Brazilian Shelf. Upwelling and downwelling winds were applied after 130 days. The distribution of low salinity waters over the shelf was more sensitive to the wind direction than to the river outflow variability. Downwelling winds were very capable of advecting the low salinity signal downshelf. Upwelling winds were efficient in eroding the plume, which was basically detached from the coast by Ekman drift. Abnormal plume intrusions toward low latitudes may be a result of the original plume position coupled with events of persistent strong downwelling favorable winds.

2019 ◽  
Author(s):  
Jonas A. Arnemann ◽  
Stephen H. Roxburgh ◽  
Tom Walsh ◽  
Jerson V.C. Guedes ◽  
Karl H.J. Gordon ◽  
...  

AbstractThe Old World cotton bollworm Helicoverpa armigera was first detected in Brazil with subsequent reports from Paraguay, Argentina, Bolivia, and Uruguay. This pattern suggests that the H. armigera spread across the South American continent following incursions into northern/central Brazil, however, this hypothesis has not been tested. Here we compare northern and central Brazilian H. armigera mtDNA COI haplotypes with those from southern Brazil, Uruguay, Argentina, and Paraguay. We infer spatial genetic and gene flow patterns of this dispersive pest in the agricultural landscape of South America. We show that the spatial distribution of H. armigera mtDNA haplotypes and its inferred gene flow patterns in the southwestern region of South America exhibited signatures inconsistent with a single incursion hypothesis. Simulations on spatial distribution patterns show that the detection of rare and/or the absence of dominant mtDNA haplotypes in southern H. armigera populations are inconsistent with genetic signatures observed in northern and central Brazil. Incursions of H. armigera into the New World are therefore likely to have involved independent events in northern/central Brazil, and southern Brazil/Uruguay-Argentina-Paraguay. This study demonstrates the significant biosecurity challenges facing the South American continent, and highlights alternate pathways for introductions of alien species into the New World.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Jonas Andre Arnemann ◽  
Stephen Roxburgh ◽  
Tom Walsh ◽  
Jerson Guedes ◽  
Karl Gordon ◽  
...  

AbstractThe Old World cotton bollworm Helicoverpa armigera was first detected in Brazil with subsequent reports from Paraguay, Argentina, Bolivia, and Uruguay. This pattern suggests that the H. armigera spread across the South American continent following incursions into northern/central Brazil, however, this hypothesis has not been tested. Here we compare northern and central Brazilian H. armigera mtDNA COI haplotypes with those from southern Brazil, Uruguay, Argentina, and Paraguay. We infer spatial genetic and gene flow patterns of this dispersive pest in the agricultural landscape of South America. We show that the spatial distribution of H. armigera mtDNA haplotypes and its inferred gene flow patterns in the southwestern region of South America exhibited signatures inconsistent with a single incursion hypothesis. Simulations on spatial distribution patterns show that the detection of rare and/or the absence of dominant mtDNA haplotypes in southern H. armigera populations are inconsistent with genetic signatures observed in northern and central Brazil. Incursions of H. armigera into the New World are therefore likely to have involved independent events in northern/central Brazil, and southern Brazil/Uruguay-Argentina-Paraguay. This study demonstrates the significant biosecurity challenges facing the South American continent, and highlights alternate pathways for introductions of alien species into the New World.


Check List ◽  
2011 ◽  
Vol 7 (6) ◽  
pp. 809 ◽  
Author(s):  
Pier Cacciali ◽  
Daniel Espínola ◽  
Silvia Centrón Viñales ◽  
Irene Gauto Espínola ◽  
Hugo Cabral

Micrurus silviae is a coralsnake with a triadal pattern, and is one of the eight species found in southern South America. In Paraguay there are six taxa recorded: M. altirostris, M. baliocoryphus, M. frontalis, M. pyrrhocryptus, M. corallinus, and M. lemniscatus carvalhoi. Here we present a record of M. silviae, an additional and seventh species for the country. Previously M. silviae was known only from Rio Grande do Sul state, in southern Brazil. The specimen was found in South American Mesopotamian Grasslands ecoregion, with natural grassland in the Department of Itapúa.


Zootaxa ◽  
2017 ◽  
Vol 4216 (3) ◽  
pp. 261 ◽  
Author(s):  
MIGUEL SIMÓ ◽  
ARNO A. LISE ◽  
GABRIEL POMPOZZI ◽  
ÁLVARO LABORDA

Three species of the genus Allocosa Banks, 1900 from southern South America are redescribed: Allocosa alticeps (Mello-Leitão, 1944), A. brasiliensis (Petrunkevitch, 1910) and A. senex (Mello-Leitão, 1945). The female of A. senex is described for the first time and the species is revalidated. A new species, A. marindia sp. nov. from southern Uruguay and southern Brazil is described. The new species is distinguished by the flattened terminal apophysis of the male bulb and the conspicuous pointed projections on the posterior margin of the female epigynum. The species inhabits in sandy estuarine and oceanic coasts with psammophile vegetation. 


2011 ◽  
Vol 11 (3) ◽  
pp. 189-196 ◽  
Author(s):  
Hélio Augusto Alves Fracasso ◽  
Joaquim Olinto Branco ◽  
Edison Barbieri

Despite being widely distributed in South America and having relatively large populations, little is known about the trophic ecology of the South American Tern (Sterna hirundinacea) and Cabot's Tern (Thalasseus acuflavidus). In Brazil, South American and Terns Cabot's breed in mixed colonies from the state of Espírito Santo to Santa Catarina. Here, we describe results of a study of the feeding ecology of these two species during the reproductive seasons of April to October of 2003, 2005 and 2006 from Cardos Island, Santa Catarina, Brazil. A total of 6248, 5140, and 4006 fishes were delivered to chicks or females by South American Terns; and 1157, 628 and 98 fish and or other prey items by Cabot's Terns during the breeding seasons of 2003, 2005, and 2006, respectively. Prey items identified included eight, seven and nine fish families for South American Terns; and, five, three and two families for Cabot's terns, in the three respective years. The number of food deliveries per chick for South American Terns was between 09:00 and 10:00 am in 2006, and between 11:00 and 12:00 am in 2005. Cabot's Terns chicks were fed in the early hours of the morning until late afternoon.


Phytotaxa ◽  
2018 ◽  
Vol 376 (2) ◽  
pp. 97
Author(s):  
HENRIK BALSLEV

Two new species of Juncus from South America are described, illustrated, and a key is provided to separate the two species from related South American species in Juncus sect. Ozophyllum. Juncus andinus is similar to J. ecuadoriensis from Venezuela, Colombia, and Ecuador, but is different in having smaller seeds and conspicuous cataphylls; it is distributed in the Andes from southern Ecuador to southern Peru. Juncus austrobrasiliensis, from Brazil, resembles J. micranthus but differs in having smaller, castaneous flower-heads and capsules with beaks that clearly protrude from the flower; it is distributed in southern Brazil from São Paulo to Santa Catarina.


Zootaxa ◽  
2019 ◽  
Vol 4671 (4) ◽  
pp. 511-526
Author(s):  
TÁCIO DUARTE ◽  
MARCOS CARNEIRO NOVAES ◽  
PITÁGORAS DA CONCEIÇÃO BISPO

The stoneflies of the family Gripopterygidae have a Gondwanan distribution (Australian, Neotropical, and Andean regions) and include about 300 species in five recognized subfamilies. The subfamily Gripopteryginae is restricted to the Neotropics and the Andean regions of South America, including 15 genera and about 80 species. Tupiperla Froehlich, with 20 species, is the largest genus among the South American Gripopteryginae. The genus has been recorded from Brazil, Paraguay, and northeastern Argentina. In Brazil, Tupiperla has been recorded from southern, southeastern, and the mountainous areas of central and northeastern, primarily from streams of the Atlantic Forest. We studied specimens of Tupiperla collected from the Atlantic Forest of southern Brazil. Herein, five new species of Tupiperla are described: T. pinhoi sp. nov., T. serrulata sp. nov., T. pessacqi sp. nov., T. ubuntu sp. nov., and T. zwicki sp. nov. 


Phytotaxa ◽  
2015 ◽  
Vol 238 (1) ◽  
pp. 1 ◽  
Author(s):  
Thiago E. C. Meneguzzo ◽  
José F. A. Baumgratz ◽  
Cássio Van den Berg

The Aganisia complex (Orchidaceae, Epidendroideae, Cymbidieae, Zygopetalinae), which comprises the genera Aganisia, Cheiradenia, Koellensteinia, Otostylis and Paradisanthus, are all revised except Koellensteinia, for which a synopsis is proposed. We reviewed 109 generic, sectional, specific and infraspecific names. Of these, five are for the first time listed as names in scheda. We propose two new combinations, 17 new synonyms, 30 typifications, and two types for which the category is corrected. Doubtful, misapplied and non-applicable names are also treated. We recognize three species and two forms of Aganisia, one species of Cheiradenia and Paradisanthus, eleven species of Koellensteinia and two species Otostylis. The Aganisia complex is completely South American, with exception of K. tricolor, which also occurs in Belize, and A. pulchella, C. cuspidata and K. graminea, in Trinidad. Aganisia and Otostylis occur predominantly in lowland areas of western and northern South America; Cheiradenia in Trinidad and the Guianas Shield; Paradisanthus mainly on the coast of eastern and southern Brazil; and Koellensteinia the most widely distributed, occurring predominantly in South America strictly north of the Tropic of Capricorn. Aganisia and Cheiradenia grow in rainforests; Paradisanthus in rainforests and coastal vegetation; Otostylis in grassy areas; and Koellensteinia in all of these.


Quaternary ◽  
2021 ◽  
Vol 4 (2) ◽  
pp. 15
Author(s):  
José Luis Prado ◽  
María Teresa Alberdi ◽  
Jonathan Bellinzoni

The Pampean Region contains sedimentary sequences with abundant mammal fossil records, which constitute the chronological outline of the Plio–Pleistocene of South America. These classic localities have been used for more than a century to correlate with other South American regions. Throughout this time, a series of misinterpretations have appeared. To understand the stratigraphic significance of these localities and the geochronological situation of each unit referring to the Pleistocene, a critical historical study of the antecedents was carried out, evaluating the state of each unit. The biostratigraphic studies of the Pampean Region’s mammalian faunas improved the understanding of biogeographic changes taking into account the environmental fluctuations of the Pleistocene.


Viruses ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 888
Author(s):  
Cecilia Olguin-Perglione ◽  
María Edith Barrandeguy

Equine influenza virus (EIV) is one of the most important respiratory pathogens of horses as outbreaks of the disease lead to significant economic losses worldwide. In this review, we summarize the information available on equine influenza (EI) in South America. In the region, the major events of EI occurred almost in the same period in the different countries, and the EIV isolated showed high genetic identity at the hemagglutinin gene level. It is highly likely that the continuous movement of horses, some of them subclinically infected, among South American countries, facilitated the spread of the virus. Although EI vaccination is mandatory for mobile or congregates equine populations in the region, EI outbreaks continuously threaten the equine industry. Vaccine breakdown could be related to the fact that many of the commercial vaccines available in the region contain out-of-date EIV strains, and some of them even lack reliable information about immunogenicity and efficacy. This review highlights the importance of disease surveillance and reinforces the need to harmonize quarantine and biosecurity protocols, and encourage vaccine manufacturer companies to carry out quality control procedures and update the EIV strains in their products.


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