scholarly journals Cladocerans (Branchiopoda) of a tropical estuary in Brazil

2005 ◽  
Vol 65 (1) ◽  
pp. 107-115 ◽  
Author(s):  
M. N Paranaguá ◽  
S Neumann-Leitão ◽  
J. D Nogueira-Paranhos ◽  
T. A. Silva ◽  
T. Matsumura-Tundisi
Keyword(s):  
Rainy Season ◽  
High Tide ◽  
River Estuary ◽  
River Mouth ◽  
Mesh Size ◽  
Marine Species ◽  
Wide Distribution ◽  
Average Density ◽  
Chemical Pollution ◽  
Tropical Estuary

The study was conducted in the Capibaribe river estuary in Recife (Brazil) to assess the role played by cladocerans in a eutrophic environment. Samplings were carried out monthly at 4 fixed stations along the estuary from July 1987 to June 1988. Collections were made with a plankton net of 65 micrometers mesh size. Six cladocerans species were registered: Penilia avirostris, Diaphanosoma spinulosum, Chydorus barroisi, Ceriodaphnia rigaudi, Ilyocryptus spinifer, and Moina micrura. The most frequent species was Moina micrura with 49%. The only true marine species was Penilia avirostris, which was registered at station 1 (close to the river mouth), during high and low tide and in the dry season. The Cladocera average density decreased from 329 ind.m-3 (August 1987, high tide) to 2 ind.m-3 (March 1988, high tide) due to the high load of organic and chemical pollution received by the estuary. At all stations, D. spinulosum, M. micrura, and C. barroisi occurred with a wide distribution, mainly during the rainy season. C. rigaudi and I. spinifer were rare, occurring only during the rainy season. Cladocerans played an important role in the food webs of the plankton community of the Capibaribe tropical estuary and the dominance of a few small species indicated a hypereutrophic environment. A high level of disturbance was indicated by the decline in diversity of specialized species and the increase in abundance of opportunistic species like M. micrura.

scholarly journals Impacts of the construction of the Port of Suape on phytoplankton in the Ipojuca River estuary (Pernambuco-Brazil)

2003 ◽  
Vol 46 (1) ◽  
pp. 73-82 ◽  
Author(s):  
Maria Luise Koening ◽  
Enide Eskinazi Leça ◽  
Sigrid Neumann-Leitão ◽  
Silvio José de Macêdo
Keyword(s):  
High Tide ◽  
River Estuary ◽  
River Mouth ◽  
Mesh Size ◽  
Marine Species ◽  
Cylindrotheca Closterium ◽  
Port Implantation ◽  
Marine Littoral ◽  
The Impact ◽  
Port Construction

In order to address the impact on phytoplankton, sampling was conducted monthly at 4 fixed stations, from April/86 to March/87 at diurnal low and high tide using a plankton net (65 mum mesh size) and a 1 L Van Dorn bottle. Among the 133 taxa identified, marine littoral euryhaline species were most common, outranking Gyrosigma balticum (Ehrenberg) Rabenhorst, Nitzschia sigma (Kützing) Wm. Smith, Licmophora abbreviata Agardh, Climacosphenia moniligera Ehrenberg, Surirella febigerii Lewis, Terpsinoe musica Ehrenberg and Cylindrotheca closterium (Ehrenberg) Reiman and Lewis. The port construction caused significant changes to the phytoplankton community with a strong influence of marine species (mainly dinoflagellate) because of the opening of the reef near the river mouth in 1983. The shallow depth and hydrodynamic brought many littoral species to the water columm. The community was composed by marine euryhaline and limnetic organisms, influenced by the salinity, rain and tide. Species diversity was high (> 3 bits.cel-1) owing to the high environmental heterogeneity (marine, freshwater and benthic interactions). After the port implantation, a strong decrease occurred in phytoplankton density owing to high loads of suspended matter. Lowest values (121,00 cells.l-1) were registered during rainy season. During dry season, when light intensity was higher, phytoplankton presented highest density ( 1,789,000 cells.l-1).

Structure and dynamics of Gobiidae larvae (Teleostei, Perciformes) in a tropical estuary: seasonal relationships with tidal cycles

2014 ◽  
Vol 94 (7) ◽  
pp. 1557-1568 ◽  
Author(s):  
Eduardo A.P. Gomes ◽  
Ana C.T. Bonecker
Keyword(s):  
Rainy Season ◽  
Fish Larvae ◽  
Abiotic Factors ◽  
River Estuary ◽  
River Mouth ◽  
Temporal Distribution ◽  
Mesh Size ◽  
Distribution Patterns ◽  
Flood Tide ◽  
Estuarine System

This study aims to describe the spatial and temporal distribution patterns of Gobiidae larvae at a tropical estuarine system in south-east Brazil (Macaé). The samples were collected in six stations, through oblique hauls using a bongo net (330 µm mesh size), coupled to a flowmeter, during the night in the ebb and flood tides in March, July and October 2006 and in February 2007. In the Macaé River estuary was collected a total of 1,234 Gobiidae larvae, representing nine taxa. The highest densities occurred in the river mouth during the flood tide in the rainy season. The most abundant groups were: Gobiosoma parri, Gobionellus oceanicus and Ctenogobius boleosoma. Gobiosoma parri was also dominant at the Macaé estuary, which also presented higher densities in the coastal stations during the rainy season (March), both the flood as the ebb tide. Gobionellus oceanicus and Ctenogobius boleosoma were characteristic of the dry season in the mouth and river stations during the flood tide. The abiotic factors chlorophyll-a and temperature were considered biologically significant for Gobiidae larvae distribution. The spatial and seasonal variations together with the tide influence the distribution of the fish larvae Gobiidae family in the Macaé River estuary and its coastal zone.

scholarly journals Planktonic rotifers from a tropical estuary under high marine influence (Passos River, PE, Brazil).

2014 ◽  
Vol 42 (3) ◽  
Author(s):  
Simone JORGE FILHO ◽  
Sigrid NEUMANN-LEITÃO ◽  
Tâmara De Almeida e SILVA ◽  
Mauro De MELO JÚNIOR
Keyword(s):  
Rainy Season ◽  
Brachionus Plicatilis ◽  
Statistical Tests ◽  
River Estuary ◽  
Mesh Size ◽  
Northeastern Brazil ◽  
Light Extinction ◽  
Physical Parameters ◽  
Salinity Regime ◽  
Light Extinction Coefficient

Passos River estuary, which is very influenced by marine waters, were carried out monthly from August/2009 to September/2010. A 64µm mesh size plankton net was hauled during low tide at two fixed stations in spring tides. Physical parameters as temperature, salinity, transparency and light extinction coefficient were obtained simultaneously. Statistical tests (Man-Whitney) were performed to evaluate possible seasonal and spatial variations. The rotifers were represented by only four species. Although there was no significant seasonal variation, the highest abundances were registered in the rainy season, with an expressive predominance of Brachionus plicatilis Müller, 1786. However, a population pick was registered in the dry season (September/2009; 13182,03 org.m-3 ) and the lowest value was registered in the rainy season (2010 May; 7,56 org.m-3 ). Brachionus plicatilis Müller, 1786 was highlighted as salinity indicator as well as its extremely opportunistic condition in eutrophic ecossistems, while Rotaria rotatoria (Pallas, 1766) and Rotaria sp. indicated organic pollution. Due to the constant high salinity regime the estuary showed few species richness. Keywords: Indicator, Rotifers, Salinity, Northeastern Brazil.

scholarly journals Phytoplankton nyctemeral variation at a tropical river estuary (Itamaracá - Pernambuco - Brazil)

2004 ◽  
Vol 64 (1) ◽  
pp. 81-94 ◽  
Author(s):  
S. R. Lacerda ◽  
M. L. Koening ◽  
S. Neumann-Leitão ◽  
M. J. Flores-Montes
Keyword(s):  
Rainy Season ◽  
River Estuary ◽  
Mesh Size ◽  
Dry Season ◽  
Tropical River ◽  
Cylindrotheca Closterium ◽  
The North ◽  
Marine Influence ◽  
Dry Seasons ◽  
Made In

The Botafogo estuary is of socio-economical importance for Pernambuco State. It is located at the north of Santa Cruz Channel, Itamaracá, Pernambuco, Brazil (07º42'50"S and 34º52'10"W). There is a critical need to understand its functioning because of the rate at which this area is being converted to land uses. The phytoplankton dynamics was studied to enhance the knowledge of and verify the possible changes which have occurred in this ecosystem. Sampling was carried out with a plankton net 65 micrometers mesh size for qualitative data, and a Van Dorn bottle for quantitative data. Concurrent hydrological and chlorophyll-a data were collected. Samplings were made in one fixed station in July 1996 (rainy season) and December 1996 (dry season), at 3-hour intervals during 24 hours. Eighty-seven specific and infra-specific taxa were identified from net plankton samples. Diatoms were most frequent, mainly Coscinodiscus centralis and Odontella regia in the rainy and dry seasons, respectively. Phytoplankton density varied from 205,000 to 1,210,000 cell.L-1 in the dry season, and from 230,000 to 2,510,000 cell.L-1 in the rainy season, indicating eutrophic conditions. Most numerically abundant were the diatoms Cyclotella meneghiniana and Cylindrotheca closterium and the phytoflagellates. The ecosystem is polluted, and deleterious effects are minimized by the marine influence which allows periodic water renewal.

scholarly journals River discharge, storm surges and tidal interactions in the Meghna river mouth in Bangladesh

MAUSAM ◽  
2021 ◽  
Vol 48 (4) ◽  
pp. 531-540
Author(s):  
ANWAR ALI ◽  
HAFIZUR RAHMAN ◽  
SYED SAZZAD HAIDER CHOWDHURY
Keyword(s):  
River Discharge ◽  
High Tide ◽  
Tidal Flow ◽  
River Estuary ◽  
River Mouth ◽  
Storm Surges ◽  
Two Dimensional ◽  
Tidal Interactions ◽  
Northern Bay Of Bengal ◽  
Surge Height

Interactions among river discharge, storm surges and tides in the Meghna river estuary in Bangladesh have been studied by using a two-dimensional vertically integrated numerical model of the northern Bay of Bengal. The study considers the interactions mostly in terms of flow across the river mouth under the three forcings, individually and in different combinations of them. River discharge and tidal flow across the river mouth act both positively and negatively depending on the tidal phase, positively during high tide and negatively during low tide. This is also true for the combination of all the three forces. On the other hand, in most of the cases, river discharge acts in opposition to the storm surges. Under certain conditions and on rare occasions they act positively. The interactions between river discharge and storm surges, however, depend on their relative magnitudes. In respect of total elevation in the estuarial region, river discharge tends to increase the surge height. However, away from the estuary, the effect of river discharge is hardly discernible.      

scholarly journals Phytoplankton in a tropical estuary, Northeast Brazil: composition and life forms

Check List ◽  
2015 ◽  
Vol 11 (3) ◽  
pp. 1633 ◽  
Author(s):  
Eveline P. Aquino ◽  
Gislayne C. P. Borges ◽  
Marcos Honorato-da-Silva ◽  
José Zanon O. Passavante ◽  
Maria G. G. S. Silva-Cunha
Keyword(s):  
Phytoplankton Community ◽  
High Tide ◽  
Spring Tide ◽  
River Estuary ◽  
Life Forms ◽  
Northeast Brazil ◽  
Tropical Estuary ◽  
Planktonic Form

We aimed verify the composition of the phytoplankton community and this life forms that occur in the Capibaribe River estuary, Pernambuco, Brazil. This is a highly impacted ecosystem by anthropic activities. We collected samples of the phytoplankton community at three stations, during three months of each season: dry, from October to December 2010; rainy, from May to July 2011. We collected samples during the low and high tide, at the spring tide. We classified the species based on life forms. We identified 127 taxa, and the majority of species were freshwater planktonic form (FP; 30%), followed by marine oceanic planktonic (MOP; 25%), marine neritic tichoplanktonic (MNT; 22%) and planktonic (MNP; 19%,), and tichoplanktonic  estuarine (TE; 3%) and freshwater (TF; 1%). The majority of species identified were diatoms, since it assumes the most variability of life forms, therefore enabling its presence in the different portions at the estuary.

Động lực phát triển vùng cửa Sông Hậu (cửa Định An - Tranh Đề)

2008 ◽  
Vol 30 (2) ◽  
pp. 130-135
Author(s):  
Hoa Mạnh Hùng ◽  
Nguyễn Quang Thành ◽  
Phan Thị Thanh Hằng
Keyword(s):  
River Estuary ◽  
River Mouth

Evaluating the dynamics of the Hau River estuary (Dinh An - Tranh De river mouth)

scholarly journals Salinity and freshwater discharge determine rotifer distribution at the Mossoró River Estuary (Semiarid Region of Brazil)

2010 ◽  
Vol 70 (3) ◽  
pp. 551-557 ◽  
Author(s):  
AMA. Medeiros ◽  
JEL. Barbosa ◽  
PR. Medeiros ◽  
RM. Rocha ◽  
LF. Silva
Keyword(s):  
Species Richness ◽  
Rainy Season ◽  
Salinity Gradient ◽  
River Estuary ◽  
Positive Influence ◽  
Freshwater Discharge ◽  
The Other ◽  
Semiarid Region ◽  
Inverse Estuary ◽  
Species Richness And Abundance

The present study aimed at evaluating differences in rotifer distribution in three estuarine zones in an inverse estuary located in the Semiarid Region of Brazil. Zones were chosen based on their proximity to the ocean and river border as a means of reflecting a horizontal salinity gradient. High freshwater discharge during the rainy season was the major determinant of rotifer composition. On the other hand, due to higher salinity values during the dry season, very low values of species richness and abundance were observed in all zones. Therefore, the study highlights the constraints of salinity and the positive influence of seasonality and river proximity on rotifer species in a semiarid estuarine environment.

Aspects of the fishery, maturation and net selectivity of the wedge sole (Dicologoglossa cuneata) off south-western Iberia: implications for fishery management

2009 ◽  
Vol 90 (7) ◽  
pp. 1465-1474 ◽  
Author(s):  
Miguel Neves Santos ◽  
Pedro Gil Lino
Keyword(s):  
Fishery Management ◽  
River Mouth ◽  
Mesh Size ◽  
Scientific Basis ◽  
Catch Per Unit Effort ◽  
Important Species ◽  
Gill Net ◽  
Catch Rates ◽  
Log Normal ◽  
First Maturity

The wedge sole (Dicologoglossa cuneata, Moreau 1881) is a commercially important species for the artisanal fleet operating off the south-western Iberian Peninsula. During 2004 and 2005 a study was undertaken aiming to provide a scientific basis for management. Data collection included information on aspects of the fishery, spawning season, size at first maturity, tangle and gill-net selectivity. Seven nominal mesh sizes were used (40, 45 and 50 mm tangle nets and 40, 50, 60 and 70 mm gill-nets). Spawning lasts from December to June, with peaks in March and May. Length at first maturity for females was estimated at 18.5 cm. Catch rates decreased sharply with increasing mesh size, with tangle nets providing the highest yields. The log-normal selectivity model provided the best fit for specimens that were wedged. The higher catch-per-unit-effort of the smaller mesh sizes and the modal length of the fitted selectivity curve being below the size-at-maturity for wedge sole, suggests that the 50 mm nominal mesh size tangle net is the most appropriate for ensuring the fishery sustainability. Nevertheless, the minimum legal size should increase to at least 18 cm and a time–area closure should be implemented off the Guadiana River mouth.

scholarly journals Distribution and density of the mollusk Donax striatus (Linnaeus, 1767) in a tropical estuarine region in the brazilian semi-arid

2015 ◽  
Vol 75 (4) ◽  
pp. 914-922 ◽  
Author(s):  
E. L. Medeiros ◽  
G. V. Fernandes ◽  
G. G. Henry-Silva
Keyword(s):  
Intertidal Zone ◽  
Significant Positive Correlation ◽  
River Estuary ◽  
Temporal Distribution ◽  
Average Density ◽  
Spatial And Temporal Distribution ◽  
Tropical Estuarine ◽  
Sampling Points ◽  
Estuarine Region ◽  
Semi Arid

Abstract This study evaluated the spatial and temporal distribution and density of the bivalve Donax striatus, at beaches close to the Apodi/Mossoró River estuary, through, six semiannual sampling campaigns were performed between April/2009 and October/2011. The sampled area was delimited by 20 transects that were laid perpendicular to the beach line and extended over 300 m in the intertidal zone. Seven sampling points were established in each transect, organisms and sediment were collected, and water temperature and salinity were recorded. The highest D. striatus average density (103 individuals.m–2) was observed in April/2009 and the lowest (18 individuals.m–2) in October/2010. The highest D. striatus densities occurred in beaches further from the estuarine region as demonstrated by a significant positive correlation (r2 = 0.67 and p = 0.0007). The D. striatus densities presented significant negative correlations with the percentages of organic matter in the water. This species demonstrated an aggregated distribution in the studied area.

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