oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

4 ( 1 )

2020 ( 2 )

2019 ( 104 )

2018 ( 196 )

Custom range...

Search Results: 1 - 10 of 72262 matches for " Rauquírio Marinho da Costa "
All listed articles are free for downloading (OA Articles)
Page 1 /72262
Display every page Item
Short and long-term temporal variation of the zooplankton in a tropical estuary (Amazon region, Brazil)
Kelli Garboza da Costa,Luci Cajueiro Carneiro Pereira,Rauquírio Marinho da Costa
Boletim do Museu Paraense Emílio Goeldi : Ciências Naturais , 2008,
Abstract: Nyctemeral and seasonal distribution of the zooplankton of the Tapera u estuary and the effect of the hydrological parameters on the dynamics of these organisms were studied in March (rainy season) and September 2005 (dry season). Zooplankton samplings were carried out during spring tides at 2-hours intervals during a 24 h period. Samples were collected with a plankton net of 120 μm mesh size. Simultaneous temperature, salinity, pH and dissolved oxygen concentration measurements were accomplished at subsurface. The estuary presented a high seasonal variation in salinity (9.1-40.0) with regimes oscillating from mesohaline to polihaline/marine during the rainy and dry season, respectively. Temperature, pH and salinity were significantly higher during the dry season. A total of 50 taxa were identified, belonging to the following groups: Arthropoda, Sarcomastigophora, Cnidaria, Mollusca, Nematoda, Platyhelminthes, Bryozoa, Chordata, Annelida and Chaetognatha. Copepods dominated quantitatively the local zooplankton with 50% of the total organisms. Total zooplankton densities oscillated from 16,491 to 397,476 ind.m-3 during the dry and rainy season, respectively. Rainfall was the principal responsible for the hydrological parameters oscillations, mainly salinity, which influenced directly the population dynamics of the zooplankton of the Tapera u estuary.
Uso e ocupa o em uma comunidade pesqueira na margem do estuário do Rio Caeté (PA, Brasil)
Iracely Rodrigues da Silva,Rauquírio Marinho da Costa,Luci Cajueiro Carneiro Pereira
Desenvolvimento e Meio Ambiente , 2006,
Abstract: This work was carried out in Bacuriteua, situated in the northeast “paraense” coastal zone in the margin of the Caeté river estuary. To characterize the type of uses and occupation in the studied area itwas necessary to define: (i) users′s profile, (ii) type of uses of the natural resources, (iii) type of services and infrastructures, and (iv) type of local buildings, to subsidy future and necessary plans ofcoastal management in the bragantinian region. The work was carried out through direct observation, tasks and questionnaires applied to the local inhabitants. The majority of the interviewed work with fishery resources and did not present complete elementary school. The pressures on the natural resources use among some local agents associated to immigration rates, failure of basic hydric canalization,urban daily cleanness and public illumination, absence of potable water net, amongst others were the main factors responsible for some social and environmental problems e.g. over exploration of the biologic resources, urban growth, decrease of public benefit, illness, amongst others. According to the actual socioeconomic status in the study area it is necessary the implementation of measures of coastalmanagement to improve the environmental status and the life quality of the local inhabitant.
Temporal distribution of the mesozooplankton in the Muriá creek, Pará, Brazil
Natália da Rocha Leite,Luci Cajueiro Carneiro Pereira,Rauquírio Marinho da Costa
Boletim do Museu Paraense Emílio Goeldi : Ciências Naturais , 2009,
Abstract: The temporal variations of the zooplanktonic community and physical and chemical water parameters were studied bimonthly between July 2003 (dry period) and May 2004 (rainy period) in the Muriá creek. Zooplankton sampling was carried out at neap tides, in daytime, using conical plankton net with 200 μm mesh size. Simultaneously, temperature, salinity and pH were measured in situ through a multiparameter probe and water samples were collected to determineconcentrations of dissolved oxygen and suspended particulate matter. It was verified a sharp temporal variation of salinity with higher values reported in the dry season. A total of 67 taxonomic groups was identified, being Arthropoda the most represented group, of which Acartia tonsa Dana, 1849 (Copepoda) had the highest densities (average values higher than 1,200 ind.m-3) recorded during the rainy period. In the dry period, Brachyura zoeae was the most abundant grouppresenting high density values. Water salinity influenced by rainfall, was the principal responsible for the temporal variations of the zooplankton community in Muriá creek.
Feeding adult of Artemia salina (Crustacea-Branchiopoda) on the dinoflagellate Gyrodinium corsicum (Gymnodiniales) and the Chryptophyta Rhodomonas baltica
Costa, Rauquírio André Albuquerque Marinho da;Koening, Maria Luise;Pereira, Luci Cajueiro Carneiro;
Brazilian Archives of Biology and Technology , 2005, DOI: 10.1590/S1516-89132005000500011
Abstract: experiments were carried out on feeding performance and survival rates of adult artemia salina exposed to no axenic strains of the dinoflagellate gyrodinium corsicum and of the chryptophyta rhodomonas baltica. filtration rates on r. baltica and g. corsicum varied from 3.35 to 7.14 ml.artemia-1.h-1 and from 2.97 to 15.86 ml.artemia-1.h-1, respectively. the ingestion rates observed for a. salina did not indicate any digestive dysfunction or physiological impairment for organisms fed on g. corsicum and their functional response were similar to those observed for other organisms like copepod fed on different food concentrations. mortality rates oscillated from 2.5% to 100% when a. salina was fed on r. baltica or g. corsicum, respectively. highest mortality rates observed for organisms fed on g. corsicum indicated that this dinoflagellate presented a hazard effect on a. salina that was not possible to confirm if it was related to toxin production or to nutritive inadequacy of this dinoflagellate as food for organisms of this species.
Urban secondary sewage: an alternative medium for the culture of Tetraselmis chuii (Prasinophyceae) and Dunaliella viridis (Chlorophyceae)
Costa, Rauquírio André Albuquerque Marinho da;Koening, Maria Luise;Macedo, Sílvio José de;
Brazilian Archives of Biology and Technology , 2004, DOI: 10.1590/S1516-89132004000300016
Abstract: the effect of different concentrations (10, 20, 30 and 40%) of urban secondary sewage on the growth of tetraselmis chuii (prasinophyceae) and dunaliella viridis (chlorophyceae) was examined to verify the possibility of its use as an alternative culture medium for these species. stocks and 700ml duplicate batch cultures were maintained under controlled laboratory conditions. 30% and 40% additions were the most efficient for the growth of both species. statistical analysis of the adjusted growth (cell.ml-1) and biomass (μg chlorophyll-a.ml-1) curves performed using the chi-square test (p<0.05) demonstrated significant differences between the nutritive medium f/2 and the 40% addition used for these two species. the results suggested that some of the concentrations tested here yielded satisfactory cell densities and growth rates when compared with other culture media (macroalgae, bovine and chicken manure extracts). thus it could be used by semi intensive aquaculture systems.
Use of secondary sewage water as a culture medium for Chaetoceros gracilis and Thalassiosira Sp (Chrysophyceae) in laboratory conditions
Costa, Rauquírio André Albuquerque Marinho da;Koening, Maria Luise;Macêdo, Sílvio José de;
Brazilian Archives of Biology and Technology , 1999, DOI: 10.1590/S1516-89131999000200011
Abstract: experiments were carried out in order to test the efficiency of additions of secondary sewage as a culture medium for chaetoceros gracilis and thalassiosira sp (chrysophyceae) under laboratory conditions. these algae were cultivated in sea water with concentrations of 10%, 20%, 30% and 40% of wastewater. the results were compared with those obtained by the nutritive medium f2 of guillard (1975). the best results in terms of cellular densities were observed at 40% additions. there were significant differences (significance levels of 5%) between the nutritive medium f2 and the 40% additions for both the species. maximum cellular densities observed for all additions tested were, 4,125.00 x 103 cells/ml for chaetoceros gracilis on the ninth day and 834.00 x 103 cells/ml for thalassiosira sp on the fifth day. biomass was higher in the nutritive medium f2 than in the other treatments, reaching average values of 2,363μg/ml for chaetoceros gracilis. at all experimental units, the best results were registered at 40% addition for chaetoceros gracilis, where average values of 0.768μg/ml were observed on the fifth day, and at 30% additions for thalassiosira sp where 0.883μg/ml were observed on the thirteenth day. it was concluded that secondary sewage could be used as a culture medium for the species tested here, after large scale tests.
Space-time distribution of zooplankton community in an Amazonian artificial coastal lagoon in Bragan a, Pará, Brazil
Adriano Augusto Vilhena Martins,Rauquírio André Marinho da Costa,Luci Cajueiro Carneiro Pereira
Boletim do Museu Paraense Emílio Goeldi : Ciências Naturais , 2006,
Abstract: The aim of this study was to report the composition and spatial temporal variation of the zooplanktonic community of the 'lagoa Salina', situated in the Caeté river estuary, Pará, Brazil. Samples were collected in three different stations distributed along the logoon through the filtration of 400 l of water in a conical-cilindric plankton net (mesh size of 75 mm). Precipitation data were also recorded. The following species were found: Criptocyclops brevifurca, Ceriodaphnia cornuta, Latonopsis australis and Brachionus sp. The most abundant species was Brachionus sp. and the species most frequent was C. brevifurca. The highest densities were registered during the rainy season and the lowest number of species was observed in the dry season. The seasonality showed an important role on the zooplankton community structure.
Filtration and ingestion rates of Thalassiosira Weissflogii (Bacillariophyta) by Euterpina acutifrons Dana (Copepoda)
Vanessa Oliveira Lemos,Rauquírio Marinho da Costa,Luci Cajueiro Carneiro Pereira
Boletim do Museu Paraense Emílio Goeldi : Ciências Naturais , 2006,
Abstract: Short-term experiments were carried out to study the feeding performances of the copepod Euterpina acutifrons fed on Thalassiosira weissiogii. Four adult females of this species were sorted and transferred to 15 ml glass bottles filled with different dilutions of the diatom cultures to obtain cell concentrations of 7.5, 10.0, 12.5, 15.0, 17.5, 20.0, 22.5 and 25.0 x 103 cell.ml-1 (8 treatments, 3 replicates, 4 copepods/replicate). Initial and final cell concentrations of control and experimental bottles were determined using a Neubauer Chamber. Filtration and ingestion rates were measured thought 1 hour grazing trials performed under controlled laboratory conditions. Filtration rates of Euterpina acutifrons oscillated from 0.81 to 2.92 ml. copepod-1 .h-1 and they significantly higher (p<0.05) on 7.5 x 103 cell.ml-1 concentration. Ingestion rates varied between 1.8 and 8.13 x 103 cell.copepod-1.h-1, showing significative differences (p<0.05) between treatments with low (7.5 x 103 cell.ml-1) and high (22.0 x 103 cell.ml-1) number of cells. The feeding rates of Euterpina acutifrons fed on Thalassiosira weissüogii revealed the important hole of this species of copepod on the aquatic food web of coastal ecosystems of the Amazonian region, especially on the northeast of Pará where it is commonly found.
Varia??o temporal do fitoplancton e dos parametros hidrológicos da zona de arrebenta??o da Ilha Canela (Bragan?a, Pará, Brasil)
Sousa, Eliane Brabo de;Costa, Vanessa Bandeira da;Pereira, Luci Carneiro Cajueiro;Costa, Rauquírio Marinho da;
Acta Botanica Brasilica , 2009, DOI: 10.1590/S0102-33062009000400018
Abstract: seasonal and nyctemeral variations of the phytoplankton and hydrological parameters were studied at a fixed station (00o46'37.2"s-046o43'24.5"w) situated in canela island (bragan?a-pará) in september and december, 2004 and in march and june, 2005. subsurface water samples were taken for qualitative and quantitative phytoplankton studies and to determine chlorophyll a concentrations. simultaneously physical and chemical parameters were measured: salinity, temperature, ph, dissolved oxygen and percent of oxygen saturation. a total of 64 taxa belonging to cyanophyta (one taxon), bacillariophyta (54 taxa) and dinophyta (nine taxa) were identified. chlorophyll a concentrations ranged from 4.67 mg m-3 (dry season), to 5.44 mg m-3 (rainy season) and follow phytoplankton densities, which were higher during the rainy period (mean values of 1,870 x 103 cell l-1). phytoflagellates quantitatively dominated the local phytoplanktonic community followed by diatoms. dimeregramma minor and skeletonema sp. were abundant and very frequent species over the studied period. resuspension processes originated by the strong winds and waves in the surf zone favored the dominance of d. minor during the dry period. in the rainy period, high rainfall, moderate winds as well as the influence of estuarine waters from tapera?u and caeté propitiated the decrease of salinity and the development of other phytoplankton species.
Microfitoplancton de águas costeiras amaz?nicas: Ilha Canela (Bragan?a, PA, Brasil)
Sousa, Eliane Brabo de;Costa, Vanessa Bandeira da;Pereira, Luci Carneiro Cajueiro;Costa, Rauquírio Marinho da;
Acta Botanica Brasilica , 2008, DOI: 10.1590/S0102-33062008000300004
Abstract: seasonal and nyctemeral variations of the microphytoplankton were studied at a fixed station (00o46'37.2''s-046o43'24.5''w) on canela island (north brazil) in september and december/2004 (dry season) and in march and june/2005 (rainy season). samples for qualitative phytoplankton studies were obtained by filtering 400 l of surface water in the surf zone of the island through plankton nets (65 μm mesh size). field work was carried out during spring tides and samples were collected every 3 hours during a 24-hour period. the collected material was fixed in neutral formaldehyde at 4%. simultaneously, salinity of the water surface was also measured. salinity showed significant variation throughout the study period, ranging from 26.1 (june/2005) to 39.0 (december/2004), characterizing the environment as euhaline-polyhaline. a total of 130 taxa were identified, belonging to cyanophyta (two taxa), bacillariophyta (115 taxa) and dinophyta (13 taxa). diatoms were the dominant group of microphytoplankton at canela island. asterionellopsis glacialis, dimeregramma minor, skeletonema sp. and thalassiosira subtilis were the most frequent and abundant taxa. high salinities favored the occurrence of polyhalobous neritic marine species. resuspension processes caused by wind and wave surf zone were responsible for exchange between planktonic and ticoplanktonic populations, including species such as dimeregramma minor, triceratium biquadratum and t. pentacrinus which represented new occurrences for the amazon coast.
Page 1 /72262
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.