scholarly journals Composition of Trichiuridae and Gempylidae larvae (Teleostei) and their association with water masses in the Southwest Atlantic Ocean

Author(s):  
Paulo Júnior ◽  
Christiane de Souza ◽  
Graciela Weiss

Composition of Trichiuridae and Gempylidae larvae (Teleostei) and their association with water masses in the Southwest Atlantic OceanIn this paper the relationship between temporal changes in the occurrence of water masses and Trichiuridae and Gempylidae larvae composition and distribution in the Southwest Atlantic ocean were analysed between 25° and 40° S. Ichthyoplankton was collected during the three expeditions of the Subtropical Convergence Project: Winter and Spring 1977, Autumn 1978 and Summer 1981, realized in the Southwest Atlantic waters. Oblique tows were conducted using a Hensen net with 250 μm mesh size. Steep salinity and temperature gradient were found, where the river outflows from La Plata river (Argentina) and Patos Lagoon (Brazil) met the Tropical Water over the continental shelf between 32 and 36° S. We examined 524 Hensen-net samples that contained about 283 larvae from five species of Trichiuridae and Gempylidae. The most abundant and frequent specie were

2012 ◽  
Vol 60 (4) ◽  
pp. 415-427 ◽  
Author(s):  
Marinês Garcia ◽  
Clarisse Odebrecht

This paper provides information on the morphology and occurrence of extant diatoms of the family Asterolampraceae and Azpeitia species of the southernmost Brazilian continental shelf and slope waters in the Southwestern Atlantic Ocean (28 -34ºS), under the influence of Tropical, Subtropical, Subantarctic Waters, terrestrial discharges from La Plata River and Lagoa dos Patos lagoon. Plankton was sampled (20 µm net; vertical hauls) at the same 27 stations in winter 2005 and summer 2007. Among Asterolampraceae, Asteromphalus flabellatus was the most frequent species (57% of samples) observed mainly in winter samples (92%) in Subtropical Shelf Water but also under the influence of La Plata River plume (salinity <35). Lower frequencies were observed for Asterolampra marylandica, Asteromphalus elegans, Asteromphalus heptactis and Spatangidium arachne. Four species of Azpeitia were observed: A. barronii and A. neocrenulata for the first time in the South Atlantic Ocean while A. africana and A. nodulifer had already been registered in equatorial and southern areas of Brazil. All Azpeitia species were rare (19%) in offshore samples (100-200 m depth. Remarks on the morphology based on light and scanning electron microcopy observations are provided along with their distribution in the study area.


Crustaceana ◽  
2011 ◽  
Vol 84 (9) ◽  
pp. 1069-1083 ◽  
Author(s):  
Chun-Ming Shin ◽  
Kuo-Ping Chiang ◽  
Chih-Jung Wu

AbstractWe examined if the results of statistical analyses of the relationship between copepod communities and water masses would be affected by the mesh size of the plankton net, by comparing abundance and species composition of copepods in plankton samples collected by plankton nets of different mesh sizes. Our samples were collected during the summer of 2006 in the East China Sea (ECS) by plankton nets with mesh sizes of 100 and 330 μm. The abundance of copepods collected by the 100 μm-mesh plankton net was about two orders of magnitude higher than that collected by the 330 μm-mesh plankton net. The difference in abundance was mainly due to the loss of small-sized copepods in the samples collected by the plankton net with the larger mesh. Species richness was higher in samples collected by the 100 μm-mesh net and Piélou's evenness was generally higher in samples collected by the 330 μm-mesh net. Although species composition of copepods varied in samples collected by plankton nets with different mesh sizes, the statistical analysis of the relationship between the copepod community and the water masses in these samples appeared not to be affected.


2021 ◽  
Vol 35 (1) ◽  
Author(s):  
María Agustina Mandiola ◽  
Ramiro Bagnato ◽  
Joaquín C. M. Gana ◽  
M. Carolina De León ◽  
Mariela Dassis ◽  
...  

In this paper, we analyze the occurrence, abundance, and type of plastic debris (PD) present on the digestive tracts of 65 white croakers (Micropogonias furnieri) catches from Rio de la Plata Estuary System (RLPES). Eighty percent of individuals analyzed had ingested PD, of which 156 were thread-like plastics (FO = 83.9 %) and 30 were fragments (FO = 16.1%). The average number of pieces per digestive tract was 2.83 ± 3.14. Microplastic represented 85% of PD, the majority of these pieces were <2 mm, and the preeminent color was blue. The RLPES is the area of the Southwest Atlantic Ocean that concentrates most of the records of plastic debris on the environment, where the white croaker is the main commercial fish. In addition, M. furnieri constitutes a key prey of several predators in the area. Although preliminary, this is a relevant contribution to the knowledge of marine debris pollution and its impact on the Southwest Atlantic Ocean organisms, particularly at the RLPES.


2019 ◽  
Vol 27 (2) ◽  
pp. 135-139
Author(s):  
Maximiliano Manuel Hernandez ◽  
Sofía Copello ◽  
Alexander Borowicz ◽  
Juan Pablo Seco-Pon

AbstractThe Spectacled Petrel Procellaria conspicillata is endemic of the Tristan da Cunha Archipelago, in the South Atlantic Ocean. However, it is scarcely detected in waters off Argentina beyond its traditional distribution along the southwest Atlantic during the breeding season. This study compiles distributional records of Spectacled Petrel for the target area (chiefly between 38°S to 46°S and 23°W to 57°W) obtained in situ, from non-systematic observations at sea, between 2015 and 2018 (totaling 4 trips); and by literature review. Nineteen new sightings of the species are presented. In 46 sightings a total of 65 individuals were recorded chiefly within waters of the Argentine continental shelf (< 200 m) (46%) and oceanic adjacent waters (54%). The bulk of the sightings (95%) were obtained during the species breeding season. In addition, we report the southernmost record of the species in oceanic waters for the southwest Atlantic (46°10′S; 57°06′W).


Zootaxa ◽  
2008 ◽  
Vol 1750 (1) ◽  
pp. 1 ◽  
Author(s):  
GENZANO GABRIEL ◽  
HERMES MIANZAN ◽  
JEAN BOUILLON

Hydromedusae are one of the best-represented planktonic groups in waters of the South Atlantic Ocean in terms of species richness. Nevertheless, medusae of the region are inadequately known because earlier studies have been limited and restricted to few areas. During the last two decades, almost 2000 samples from 54 research cruises have been collected, mostly within the continental shelf of Argentina and Uruguay (33 – 55º S). These samples provide an opportunity to significantly augment knowledge of the richness of the medusa fauna in the southwest Atlantic. Forty species of hydromedusae (six of them new records for the area), including 15 of Anthomedusae, 14 of Leptomedusae, three of Limnomedusae, four of Narcomedusae, and four of Trachymedusae, were identified. Our results indicate that previous lists overestimated species richness of hydromedusae in the area. When misidentifications, updated species synonymies, and doubtful records are taken into account, 71 valid species are recognized here from the study area. Based upon this corrected inventory list, the data suggest that the number of species of hydromedusae decreases markedly with increasing latitude, corresponding with that observed in other planktonic groups of invertebrates.


2018 ◽  
Vol 3 (4) ◽  
pp. 253-264 ◽  
Author(s):  
Leticia Burone ◽  
Paula Franco-Fraguas ◽  
Michel Mahiques ◽  
Leonardo Ortega

The Uruguayan Continental Margin is located in a strategic location of great relevance to understand the dynamics of the regional and global climate and to study the sedimentary processes. The Río de la Plata represents the largest fluvial discharge of the Southwest Atlantic (23.000 m3/s of water and 57.000.000 m3/year of sediment for the South Atlantic Ocean). The sub-surface and deep circulation are characterized by the confluence of water masses with contrasting thermohaline characteristics that determine the formation of well-marked hydrological fronts. In the continental shelf, this characteristic is represented by the Subtropical Shelf Front, as a shallow extension of the Brazil-Malvinas Confluence that occurs in deep water off the shelf. Although the knowledge of the regional circulation is acceptable, there are significant gaps in the knowledge related to the influence of this complex hydrological system on sedimentation processes. The objective of this work is to synthesize the present knowledge about the morpho-sedimentary characteristics of the Uruguayan Continental Margin and the processes involved in its formation. It also aims to discuss some knowledge gaps that are the subject of current research in the region. The knowledge reflects the scientific-technological evolution at a global level that is translated in the increase of recent works on the continental slope. Nowadays, most of the available information is associated with the inner shelf and upper slope. Starting from the basis of the close relationship between bathymetry and sedimentological distribution it is clear that efforts should be concentrated on the better understanding of the interaction between the shelf and the slope. The scientific knowledge regarding sedimentology and geochemistry along the Uruguayan Continental Margin is still, scarce and heterogeneous. However, it indicates complexity in the sedimentary coverture present both in the continental shelf and slope. The Uruguayan Continental Margin can be considered as an in situ laboratory to improve the understanding of the influence of oceanic hydrodynamics on the margin configuration, a key point to achieve better paleoceanographic interpretations. In this sense, due to the complexity of both modern hydrology and morphological configuration of the margin, it would be interesting to understand the relative importance of the control of each environment on surface sedimentation. A better understanding of the processes that link the near bottom circulation and continental slope features is needed. At the same time, this will allow deepening a new field of research in Uruguay, considering the joint and interrelated vision between sedimentary and oceanographic processes. ResumoA Margem Continental do Uruguai está localizada num local estratégico de grande relevância para entender a dinâmica do clima regional e global e para estudar os processos sedimentares. O Río de la Plata representa a maior descarga fluvial do Atlântico Sudoeste (23.000 m3/s de água e 57.000.000 m3/ano de sedimento para o Oceano Atlântico Sul). A circulação de subsuperfície e profunda são caracterizadas pela confluência de massas de água com características termohalinas contrastantes que determinam a formação de frentes hidrográficas bem marcadas. Na plataforma continental, essa característica é representada pela Frente Subtropical da Plataforma, uma extensão rasa da Confluência Brasil-Malvinas que ocorre em águas profundas ao largo da plataforma. Embora seja considerável o conhecimento da circulação regional, existem lacunas significativas no conhecimento da influência deste complexo sistema hidrológico nos processos de sedimentação. O objetivo deste trabalho é sintetizar o conhecimento atual sobre as características morfo-sedimentares da Margem Continental Uruguaia e os processos envolvidos na sua formação. Também pretende discutir algumas lacunas de conhecimento que são objeto de pesquisas atuais na região. O conhecimento reflete a evolução científico-tecnológica a nível global, que se traduz no aumento de trabalhos recentes na vertente continental. Atualmente, a maior parte da informação disponível está associada à plataforma continental interna e ao talude continental superior. Partindo da base da estreita relação entre a batimetria e a distribuição sedimentológica, torna-se claro que os esforços devem ser concentrados na melhor compreensão da interação entre a plataforma e o talude continental. O conhecimento científico sobre sedimentologia e geoquímica ao longo da Margem Continental do Uruguai é ainda escasso e heterogêneo. No entanto, os dados existentes indicam que a cobertura sedimentar presente tanto na plataforma quanto no talude continental é complexa. A Margem Continental do Uruguai pode ser considerada um laboratório in situ para melhorar a compreensão da influência da hidrodinâmica oceânica na configuração da margem, ponto chave para se obterem melhores interpretações paleoceanográficas. Nesse sentido, devido à complexidade da hidrologia moderna e da configuração morfológica da margem, seria interessante entender a importância relativa do controle de cada ambiente sobre a sedimentação superficial. É necessário um melhor entendimento dos processos que ligam as características de circulação próxima do continente à que ocorre no talude continental. Este conhecimento permitirá aprofundar um novo campo de pesquisa no Uruguai, considerando a visão conjunta e inter-relacionada entre processos sedimentares e oceanográficos. 


2007 ◽  
Vol 55 (3) ◽  
pp. 167-177 ◽  
Author(s):  
María Cristina Oddone ◽  
Laura Paesch ◽  
Walter Norbis ◽  
Gonzalo Velasco

A total number of 4824 Mustelus schmitti was sampled. Females ranged from 25 to 93 cm in spring and from 28 to 90 cm in summer. Males ranged from 34 to 82 and from 28 to 77 cm, respectively. Length composition of the population showed significant differences between spring and summer being females larger than males. Total length distribution did not show significant differences between cruises. Males density varied significantly between cruises while for the females no significant variation was observed. In the spring cruise, both sexes occurred at depths lower than 50 m. Females occurred in the whole area with adult occurrence only above 35°30'S. Mature males occurred throughout the area, immature males occurring in two trawls in Samborombón Bay. The summer cruise showed a discontinuous distribution of the species along the study area resulting in spatial segregation in two groups with immature females predominating in both of them.


2019 ◽  
Vol 35 (3) ◽  
pp. 655-671
Author(s):  
Ana Cristina Teixeira Bonecker ◽  
Mario Katsuragawa ◽  
Márcia Salustiano Castro ◽  
Claudia Namiki ◽  
Maria Lourdes Zani‐Teixeira ◽  
...  

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2587 ◽  
Author(s):  
Catherine Gérikas Ribeiro ◽  
Adriana Lopes dos Santos ◽  
Dominique Marie ◽  
Vivian Helena Pellizari ◽  
Frederico Pereira Brandini ◽  
...  

Pico and nanoplankton communities from the Southwest Atlantic Ocean along the Brazilian Bight are poorly described. The hydrography in this region is dominated by a complex system of layered water masses, which includes the warm and oligotrophic Tropical Water (TW), the cold and nutrient rich South Atlantic Central Water (SACW) and the Coastal Water (CW), which have highly variable properties. In order to assess how pico- and nanoplankton communities are distributed in these different water masses, we determined by flow cytometry the abundance of heterotrophic bacteria,Prochlorococcus,Synechococcusand autotrophic pico and nanoeukaryotes along three transects, extending from 23°S to 31°S and 39°W to 49°W. Heterotrophic bacteria (including archaea, maximum of 1.5 × 106cells mL−1) were most abundant in Coastal and Tropical Water whereasProchlorococcuswas most abundant in open-ocean oligotrophic waters (maximum of 300 × 103cells mL−1).Synechococcus(up to 81 × 103cells mL−1), as well as autotrophic pico and nanoeukaryotes seemed to benefit from the influx of nutrient-rich waters near the continental slope. Autotrophic pico and nanoeukaryotes were also abundant in deep chlorophyll maximum (DCM) layers from offshore waters, and their highest abundances were 20 × 103cells mL−1and 5 × 103cells mL−1, respectively. These data are consistent with previous observations in other marine areas whereSynechococcusand autotrophic eukaryotes dominate mesotrophic waters, whereasProchlorococcusdominate in more oligotrophic areas. Regardless of the microbial community structure near the surface, the carbon stock dominance by autotrophic picoeukaryotes near the DCM is possibly linked to vertical mixing of oligotrophic surface waters with the nutrient-rich SACW and their tolerance to lower light levels.


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