scholarly journals Effects of dredging operations on soft bottom macrofauna in a harbor in the Patos Lagoon estuarine region of southern Brazil

2005 ◽  
Vol 65 (4) ◽  
pp. 573-581 ◽  
Author(s):  
C. E. Bemvenuti ◽  
L. G. Angonesi ◽  
M. S. Gandra
Keyword(s):  
Cluster Analysis ◽  
Rio Grande ◽  
Sampling Period ◽  
Southern Brazil ◽  
Soft Bottom ◽  
Patos Lagoon ◽  
Bottom Community ◽  
Estuarine Species ◽  
Estuarine Region

An evaluation was made of the effects of dredging on the soft bottom community in the channel of the Rio Grande harbor in the Patos Lagoon estuarine region of southern Brazil. During four seasonal cruises, samples were collected from nine biological stations, one of which was located outside the dredged area. Three macrobenthic samples were collected on each cruise from each station, using a 0.08 m² van Veen grab. A cluster analysis was applied to group summer and autumn cruise stations before the dredging period, revealing larger numbers of species (35-36 spp.) and higher densities of organisms. The station located outside the dredging area was always included in this group, regardless of the sampling period or conditions of salinity. Another group comprised the winter and spring stations during the dredging period. This group was characterized by stations with the fewest species (20-18 spp.) and the lowest and most variable organism densities. The efficient strategies of resilience of the dominant estuarine species may minimize the effects of dredging on the biota through the rapid recolonization of the soft bottom of the harbor channel.

scholarly journals Distribution and abundance of the Lesser electric ray Narcine brasiliensis (Olfers, 1831) (Elasmobranchii: Narcinidae) in southern Brazil in relation to environmental factors

2009 ◽  
Vol 57 (2) ◽  
pp. 105-112 ◽  
Author(s):  
Gabriel Maciel de Souza Vianna ◽  
Carolus Maria Vooren
Keyword(s):  
Coastal Water ◽  
Latitudinal Gradient ◽  
Seasonal Pattern ◽  
Rio Grande ◽  
Bottom Trawl ◽  
Trawl Survey ◽  
Southern Brazil ◽  
Rio Grande Do Sul ◽  
Patos Lagoon ◽  
Tropical Water

The distribution and abundance of the lesser electric ray, Narcine brasiliensis, was assessed based on bottom-trawl survey data collected off the coast of Rio Grande do Sul, southern Brazil. Between 1980 and 1984 and in 2005, 416 bottom trawl hauls were carried out at depths of 10-100 m. Narcine brasiliensis occurred mainly in waters with bottom temperature between 20 and 25ºC. Density of the species was higher between the depths of 10 and 20 m, during the summer and autumn. The seasonal pattern of N. brasiliensis in the shallow coastal water of Rio Grande do Sul reflects a southward migration in summer. This is conditioned by the southward advance of warmer and high-salinity Tropical Water of the Brazil Current In winter, the return or northward migration is a response to seasonal cooling of the coastal waters and to the northward advance of cold Coastal Water of lower salinity. The latitudinal gradient in density of N. brasiliensis was related to the latitudinal gradient in salinity of the bottom waters. This was caused by the freshwater runoff from the Patos Lagoon establishing a physical barrier to the occurrence of the species farther south than the city of Rio Grande.

Description of Two New Species of the Genus Vorticella (Ciliophora: Peritrichia) Epibionts on Pomacea canaliculata (Mollusca: Ampullariidae: Gastropoda) in Southern Brazil

Zootaxa ◽  
2018 ◽  
Vol 4508 (2) ◽  
pp. 211
Author(s):  
MARCOS W. O. PEREIRA ◽  
FABIANO CARVALHO De BRITO ◽  
EDUARDO EIZIRIK ◽  
LAURA R. P. UTZ
Keyword(s):  
New Species ◽  
Rio Grande ◽  
The Other ◽  
Pomacea Canaliculata ◽  
Regular Pattern ◽  
Southern Brazil ◽  
Rio Grande Do Sul ◽  
Patos Lagoon ◽  
Two New Species ◽  
Scanning Electron

The peritrich ciliates Vorticella veloxiiforme n.sp. and Vorticella ampullaria n.sp. were found as epibionts on the ampullarid mollusk Pomacea canaliculata collected from Patos Lagoon, Rio Grande do Sul state, Brazil. The detailed morphology of both species was investigated using live and stained specimens, as well as scanning electron microscopy. Zooids of Vorticella veloxiiforme are cup shaped measuring 57 X 41 μm on average. A J-shaped macronucleus lies in the upper half of the cell. One contractile vacuole was observed in the upper part of the cell. V. ampullaria presents an elongate zooid measuring 70 X 25 µm on average. A C-shaped macronucleus lies in the middle of the cell. Two contractile vacuoles are present: one close to the peristome and the other in the lower half of the cell. The pattern of oral polykinetids was typical of the genus, with all infundibular polykinetids composed by three rows of kinetosomes each. SEM revealed a regular pattern of pores present on the zooid membrane of both species. Analyses of the 18s rDNA placed the two new species in the order Vorticellida close to described species of Vorticella. 

scholarly journals Gauchergasilus euripedesi (Copepoda, Ergasilidae) parasitizing different species of fish from two environments in southern Brazil

2021 ◽  
Vol 16 (2) ◽  
pp. 289-298
Author(s):  
Moisés Gallas ◽  
Laura R. P. Utz
Keyword(s):  
Electron Microscopy ◽  
Fish Species ◽  
Rio Grande ◽  
Parasitic Copepod ◽  
Southern Brazil ◽  
Rio Grande Do Sul ◽  
Porto Alegre ◽  
Patos Lagoon ◽  
Estuarine Area ◽  
Scanning Electron

The parasitic copepod Gauchergasilus euripedesi (Montú, 1980) Montú & Boxshall, 2002 was described from plankton samples and specimens found in four fish species from the estuarine area of Patos Lagoon, state of Rio Grande do Sul (RS), Brazil. Later, one different fish species was reported parasitized with G. euripedesi in the same locality. Species of Astyanax Baird & Girard, 1854 (Astyanax henseli Melo & Buckup, 2006 and Astyanax lacustris (Lütken, 1875)) and Psalidodon Eigenmann, 1911 (Psalidodon eigenmanniorum (Cope, 1894) and Psalidodon aff. fasciatus (Cuvier, 1819)) were collected in two environments (Pintada Island, municipality of Porto Alegre and Itapeva Lagoon, municipality of Terra de Areia, RS) to investigate their parasites. The copepods found in the gill arches were counted, processed, mounted in permanent slides, and photographed using light microscopy, or processed for observation in scanning electron microscopy. Specimens of P. eigenmanniorum from Pintada Island, A. lacustris and P. aff. fasciatus from Itapeva Lagoon, were parasitized by G. euripedesi, with prevalences of 29.03% (A. lacustris), 10.34% (P. eigenmanniorum), and 9.68% (P. aff. fasciatus). Measurements obtained for specimens of G. euripedesi were similar to those found in the literature, except for egg sacs which were larger in the specimens examined in the present study. In addition to being the first report of G. euripedesi parasitizing species of fish (A. lacustris, P. eigenmanniorum, and P. aff. fasciatus), the results presented here also extend the known geographic distribution of the copepod species.

scholarly journals The DiatomAnorthoneis dulcisHein from Southern Brazil: Morphology and Ecology

2008 ◽  
Vol 2008 ◽  
pp. 1-5 ◽  
Author(s):  
Garcia Marinês ◽  
Talgatti Dávia Marciana
Keyword(s):  
Fine Structure ◽  
South America ◽  
Relative Abundance ◽  
Environmental Parameters ◽  
Rio Grande ◽  
Southern Brazil ◽  
Rio Grande Do Sul ◽  
Patos Lagoon ◽  
Original Diagnosis ◽  
Structure Morphology

A new geographic locality forAnorthoneis dulcisis reported. The paper describes the distribution and relative abundance ofA. dulcisin Lagoa dos Patos lagoon (a lagoon in Rio Grande do Sul state, Brazil) from samples collected between 2004 and 2005, and shows that this rare species is present all year round. This study extends the species distribution to South America indicating that the species can thrive on sand grains in lentic estuarine, and freshwater areas. It widens the range of tolerance to environmental parameters. The valve fine structure, morphology, and dimensions are in agreement with the original diagnosis.

scholarly journals The fish fauna of the Corrientes stream basin, Patos lagoon system, state of Rio Grande do Sul, southern Brazil

Check List ◽  
2012 ◽  
Vol 8 (1) ◽  
pp. 077 ◽  
Author(s):  
Matheus Vieira Volcan ◽  
Luis Esteban Krause Lanés ◽  
Ândrio Cardozo Gonçalves ◽  
Alinca Peres da Fonseca ◽  
Maximiano Pinheiro Cirne
Keyword(s):  
Fish Fauna ◽  
Rio Grande ◽  
System State ◽  
Southern Brazil ◽  
Rio Grande Do Sul ◽  
Patos Lagoon ◽  
Lagoon System

The fish sampled in this study were captured in seasonal collections samplings, conducted between May 2006 and February 2007 in 15 stretches of the Corrientes stream basin, Patos lagoon system, Rio Grande do Sul state, Brazil. A total of 8088 specimens were collected, belonging to nine orders, 24 families and 68 species. In general, the ichthyofauna in this basin has the same pattern recognized for Neotropical rivers with predominance of Characiformes and Siluriformes orders and a high representative of the Characidae and Loricariidae families.

scholarly journals Shallow gas accumulation in sediments of the Patos Lagoon, southern Brazil

2006 ◽  
Vol 78 (3) ◽  
pp. 607-614 ◽  
Author(s):  
Jair Weschenfelder ◽  
Iran C.S. Corrêa ◽  
Salvador Aliotta ◽  
Carla M. Pereira ◽  
Vinicius E.B. de Vasconcelos
Keyword(s):  
Coastal Plain ◽  
Rio Grande ◽  
Sedimentary Facies ◽  
Seismic Survey ◽  
Southern Brazil ◽  
Seismic Profiles ◽  
Shallow Gas ◽  
Patos Lagoon ◽  
Good Penetration ◽  
Seismic Anomalies

A high resolution seismic survey was conducted in the Patos Lagoon, southern Brazil, aboard of the research vessel LARUS of the Fundação Universidade Federal do Rio Grande (FURG). Around 400 km of 3.5 kHz seismic profiles were collected, which provided acoustic signals of good penetration depth and resolution. Seismic anomalies, including turbidity and pocket gas, revealed that gas-charged sediments are common in several areas of the lagoon. The gas accumulations in the Patos Lagoon are controlled by the spatial distribution of the sedimentary facies. Either in 'curtains' or in 'acoustic turbid zones', the main gas accumulations occur in areas with paleotopographic lows related to fluvial channels and valleys developed in the Rio Grande do Sul coastal plain during regressive/transgressive events of the Quaternary.

scholarly journals Pisces, Perciformes, Gobiidae, Ctenogobius stigmaticus (Poey, 1860): new species record at Patos Lagoon estuary, state of Rio Grande do Sul, Brazil

Check List ◽  
2010 ◽  
Vol 6 (1) ◽  
pp. 056 ◽  
Author(s):  
Marcelo Dias de Mattos Burns ◽  
Alexandre Miranda Garcia ◽  
João Paes Vieira
Keyword(s):  
New Species ◽  
Present Note ◽  
Rio Grande ◽  
Southern Brazil ◽  
Rio Grande Do Sul ◽  
Patos Lagoon ◽  
Gobiid Fish ◽  
Patos Lagoon Estuary ◽  
First Time

The present note records for the first time the gobiid fish Ctenogobius stigmaticus (Poey, 1860) at Patos Lagoon stuary, state of Rio Grande do Sul, southern Brazil. The known distribution of this species is therefore extended 600 km southwards.

scholarly journals Numerical Study of Oil Spill in the Patos Lagoon Under Flood and Ebb Conditions

2019 ◽  
Vol 7 (1) ◽  
pp. 4 ◽  
Author(s):  
Bruno Vasconcellos Lopes ◽  
Ana Pavlovic ◽  
Thaísa Beloti Trombetta ◽  
Phelype Oleinik ◽  
Caroline Barbosa Monteiro ◽  
...  
Keyword(s):  
Oil Spill ◽  
Oil Spills ◽  
Numerical Study ◽  
Rio Grande ◽  
Computational Domain ◽  
Hydrodynamic Conditions ◽  
Rio Grande Do Sul ◽  
Patos Lagoon ◽  
Oil Slick ◽  
Estuarine Region

Facing great obstacles to eradicate environmental hazards generated by oil spills, it is crucial to establish actions against such accidents. In this context, the focus of this study is to analyze oil spills at the harbor region of Rio Grande, Rio Grande do Sul. The Easy Coupling Oil System (ECOS) model was used to model the oil spills under different environmental conditions simulated by the hydrodynamic model Telemac-3D, with the intention to identify the main forces controlling the movement of the oil slicks over a year of averaged hydrodynamic conditions from 2003 to 2015. The computational domain comprises the Patos Lagoon, the harbor area of Rio Grande and the Southern Brazilian Shelf. For the oil spill simulations, eight distinct events were defined considering both flood and ebb conditions in the estuarine region of the Patos Lagoon. The oil spill simulations showed that, in ebb conditions, the oil slick movement is mainly ruled by the currents, moving towards the outflow. After a few hours, the wind action makes the slick move towards the margins of the waterway. In flood conditions, on the other hand, the oil slick drifts to the interior of the estuary, following the dominant currents and the local winds.

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