Observações preliminares sobre a toxicidade do ϒBHC e do cloreto de mercúrio à Artemia salina

Results of bio-assays using Artemia salina larvae in γBHC-HgCl2 mixture are presented. The results obtained are compared with those obtained using the two chemicals separately. The LC50 for γBHC was almost double that for HgCl2. The effect due to the primary dose of HgCl2 was observed for approximately 16% of the population (LC2.3) while for γBHC the population percentage was 2.3 (LC2.3). As a consequence, subsequent doses were more effective for HgCl2 than for γBHC. The effective dose 50% (ED50) is about the same for γBHC and for γBHC + HgCl2 mixture, though in higher doses BHC would be more effective, while in smaller doses the mixture would predominate.São apresentados os resultados de bioensaios com larvas de Artemia salinacolocadas em misturas de γBHC e HgCl2, a fim de se compararem os efeitos das mesmas com aqueles obtidos quando essas duas substancias atuam isoladamente. A CL50 para o yBHC foi quase que o dobro do valor para o HgCl2. O efeito da primeira dose foi observado para aproximadamente 16% da população (CL16), enquanto que, para o γBHC, o foi em 2,3% da população (CL2,3). Assim, as doses subseqüentes foram mais efetivas para o HgCl2 que para o γBHC. A dose efetiva 50% (ED50) ê mais ou menos igual para o γBHC e para o γBHC + HgCl2, mas em doses altas o YBHC seria mais efetivo, enquanto que em doses baixas a mistura e que o seria

Vertical distribution of planktonic foraminifera in the southwestern Atlantic

Abstrac

Benthic communitystructureandorganicmattervariationin response to oceanographic events on the Brazilian SE inner shelf

For 13 months, this study monitored the sedimentary organic matter composition, benthic bacteria and macro fauna at a permanent sampling station on the inner shelf(_ 40 depth) near Ubatuba in SE Brazil. The sedimentary organic matter compounds were evaluated for total organic matter content, lipid biomarkers and phyto pigments. The organic matter content varied significantly overtime but no clear seasonal trend was evident Lipid bio marker composition revealed that particulate organic matter was primarily derived from autochthonous sources, such as diatoms, other microalgae, zooplankton, sediment bacteria and benthic metazoan fauna. Phyto pigment results revealed that the majority of the organic matter in the sediments was refractory a supposed to labile, suggesting that the labile portion is rapidly consumed. The benthic dynamics off the coast of by the intrusion of the South Atlantic Central Water(SACW) on to the shelf, which brings nutrients up to the euphotic zone and stimulates new phyto planktonic production. This enhances the flux of organic matter to the bottom and increases benthic biota density, mainly bacteria .These results suggest a strong and complex benthic–pelagic coupling that is influenced by both mesoscale oceanographic events(i.e., intrusion of SACW) and local events (cold fronts) through remobilization f the sediment

Comparison of the responses of growth and Photosynthesis of three clones of Phaeodactylum tricornutum

Através de bioensaios estáticos fo-ram comparadas as taxas máximas de crescimento, razão de fotossintese em termos de clorofila-a e de célula, bem como o rendimento final de tres clones de Phaeodacty-tum tricornutum visando verificar uma possível existência de diferenças intraespe-cificas entre eles. Dois desses clones foram isolados a partir de amostras de Uba-tuba (U3, isolado em 1972 e U5 isolado em 1979) e um de Cananéia (Cl, isolado em 1980). Todos os resultados foram submeti-dos a uma análise de variância trifatorial e a uma anállse de agrupamento com a finlidade de discriminar as condições experimentais nas quais os tres clones diferi-ram significativamente em suas respostas fisiológicas. Durante a fase exponencial de crescimento os tres clones se apresen-taram com morfótipos fusiformes raramente se encontrando morfótipos ovóides e trir-radiados. O padrão das curvas de cresci -mento dos tres clones em diferentes temperaturas (16, 20, 240 C) e meios de cultu-ra (ASP 2, Erd-Schreiber, Guillard fl) não diferiu. Os resultados obtidos indicaram a existência de diferenças significativas nas taxas de crescimento e produti-vidade primária. Morfótipo ovóides for-mando grumos foram observados nos tres clones após a fase exponencial e de modo conspícuo no clone U5. Nas mesmas condi-ções, o clone Cl apresentou uma grande quantidade de grumos, com a forma de uma estrela, constituidos por morfótipos fusiformes unidos convergentemente por uma das extremidades de cada célula. Por outro lado, morfótipos trirradiados e cru-ciformes bem como formação de cadeias, só foram observados no clone U3.A comparison of the maximum growth rates, primary productivity on chlorophyll -a and cell basis, and maximum yield achieved in batch culture of three clones of Phaeodactylum tricornutum has been carried out in order to cheek intraespecifie differences among them. Two of the clones were isolated from samples of Uba-tuba (U3, isolated in 1972 and U5, in 1979 ), while the third one was isolated from samples of Cananéia (C1, isolated in 1980). Three-way analysis of variance was accom-plished and cluster analysis was carried out to distinguish the experimental conditions in which the clones would show distinct physiological responses. During the log phase of growth the three clones usually presented fusiform type of cells. Never theless, rare oval and triradiate cells have been observed. The pattern of the growth curves submitted todifferent temperatures (16,20,24º C) and media (Guillard f1. Erd-Schreiber, ASP2) was the same for the three clones. The results indieated significant differenees in growth rates and primary productivity. Oval morphotypes in clusters have been observed in all clones after the log phase under exausted media. The clone U5 has exhibited this be haviour in a prominent way. Many star-shape clusters, constituted of fusiform morphotypes linked by one of the extremities of each cell were observed in clone Cl. Un the other hand, triradiate and cruciform cells, and the formation of chains, were observed only in clone U3

Comparison of the responses of growth and Photosynthesis of three clones of Phaeodactylum tricornutum

Através de bioensaios estáticos fo-ram comparadas as taxas máximas de crescimento, razão de fotossintese em termos de clorofila-a e de célula, bem como o rendimento final de tres clones de Phaeodacty-tum tricornutum visando verificar uma possível existência de diferenças intraespe-cificas entre eles. Dois desses clones foram isolados a partir de amostras de Uba-tuba (U3, isolado em 1972 e U5 isolado em 1979) e um de Cananéia (Cl, isolado em 1980). Todos os resultados foram submeti-dos a uma análise de variância trifatorial e a uma anállse de agrupamento com a finlidade de discriminar as condições experimentais nas quais os tres clones diferi-ram significativamente em suas respostas fisiológicas. Durante a fase exponencial de crescimento os tres clones se apresen-taram com morfótipos fusiformes raramente se encontrando morfótipos ovóides e trir-radiados. O padrão das curvas de cresci -mento dos tres clones em diferentes temperaturas (16, 20, 240 C) e meios de cultu-ra (ASP 2, Erd-Schreiber, Guillard fl) não diferiu. Os resultados obtidos indicaram a existência de diferenças significativas nas taxas de crescimento e produti-vidade primária. Morfótipo ovóides for-mando grumos foram observados nos tres clones após a fase exponencial e de modo conspícuo no clone U5. Nas mesmas condi-ções, o clone Cl apresentou uma grande quantidade de grumos, com a forma de uma estrela, constituidos por morfótipos fusiformes unidos convergentemente por uma das extremidades de cada célula. Por outro lado, morfótipos trirradiados e cru-ciformes bem como formação de cadeias, só foram observados no clone U3.A comparison of the maximum growth rates, primary productivity on chlorophyll -a and cell basis, and maximum yield achieved in batch culture of three clones of Phaeodactylum tricornutum has been carried out in order to cheek intraespecifie differences among them. Two of the clones were isolated from samples of Uba-tuba (U3, isolated in 1972 and U5, in 1979 ), while the third one was isolated from samples of Cananéia (C1, isolated in 1980). Three-way analysis of variance was accom-plished and cluster analysis was carried out to distinguish the experimental conditions in which the clones would show distinct physiological responses. During the log phase of growth the three clones usually presented fusiform type of cells. Never theless, rare oval and triradiate cells have been observed. The pattern of the growth curves submitted todifferent temperatures (16,20,24º C) and media (Guillard f1. Erd-Schreiber, ASP2) was the same for the three clones. The results indieated significant differenees in growth rates and primary productivity. Oval morphotypes in clusters have been observed in all clones after the log phase under exausted media. The clone U5 has exhibited this be haviour in a prominent way. Many star-shape clusters, constituted of fusiform morphotypes linked by one of the extremities of each cell were observed in clone Cl. Un the other hand, triradiate and cruciform cells, and the formation of chains, were observed only in clone U3

Environmental forcing on phytoplankton biomass and primary productivity of the coastal ecosystem in Ubatuba region, southern Brazil

A time series of chlorophyll a and in situ primary production sampled over a period of 33 days during summer in Ubatuba region, southeastem Brazil, was subjected to multivariate and harmonic analysis. Principal Component Analysis has revealed four factors interpreted as (i) South Atlantic Central Water forcing; (ii) Transient ftontal systems and rain fali forcings; (iii) Wind forcing normal to the coast; (iv) Wind forcing parallel to the coast, as main factors in the variability of the phytoplankton biomass and primary productivity. Splitting of the time series according to four main events which had profound effects on the physicochemical characteristics of the region showed the following variations in the primary productivity integrated over the photic layer (g C m-2 day-1): mixing&#8594;stratification period, 0.40 ± 0.11; heavy rainfall, 1.24± 0.28; stratification after rainfall, 0.74± 0.10; stratification&#8594;mixing period, 0.90± 0.27; stratification after deep mixing, 0.63 ± 0.28. Harmonic analysis revealed two indistinguishable significant peaks of the phytoplankton biomass - one at a period of 8.25 days and one at a period of 6.6 days, contributing, respectively, about 17 and 32% ofthe total variance. Atmospheric forcing showed a characteristic period,of 200-264 hours while phytoplankton biomass response ranged over the 144-192 hours time scales and primary productivity was best related to the environment 360 hours before. Relative to total nitrogen' and ' biomass primary productivity oscillations were lagged about 96-144 hours. The interruption of steady-state conditions by transient atmospheric ev~nts and wind field intensification are the determining factors driving phytoplankton changes in this coastal environment.<br>Uma série temporal de clorofila a e produção primária obtida em um período de 33 dias durante o verão na região de Ubatuba, sudeste do Brasil, foi submetida à análise multivariada e harmônica. A Análise de Componentes Principais revelou quatro fatores interpretados como (i) Água Central do Atlântico Sul; (ii) Sistemas ftontais transientes e chuvas; (iii) Ventos normais à costa; (iv) Ventos paralelos à costa. Estes fatores atuam como forçantes ambientais na determinação da variabilidade observada na biomassa fitoplanctônica e produtividade primária. A divisão da séríe temporal de acordo com quatro eventos modificadores das características fisicoquímicas da região mostrou a seguinte variabilidade na produção primária integrada (g C m,2 dia,l) na camada eufótica: coluna de água homogênea em processo de estratificação térmica- 0,4O±0, 11; coluna de água estratificada e chuvas intensas- 1,24±0,28; coluna de água misturada em fase de estratificação térmica após intensas chuvas- 0,74:f:0,10; coluna de água estratificada em fase de processo de mistura- 0,90±0,27; coluna de água homogênea em fase de estratifição térmica após intensa mistura- 0,63±0,28. A Análise Harmônica revelou dois picos de biomassa significativos- um com período de 8,25 dias e outro com período de 6,6 dias, contribuindo, respectivamente, com 17 e 32% da variância total da série. A forçante atmosférica apresentou um período característico de 200-264 horas enquanto que a escala de resposta da biomassa fitoplanctônica variou de 144-192 horas e a de produtividade primária um período de 360 horas. Em relação à biomassa e nitrogênio total, a produtividade primária apresentou uma defasagem de 96-144 horas

Comparação de produtos MODIS-Aqua de cor do oceano com dados in situ em águas costeiras de Ubatuba (SP), plataforma continental sudeste brasileira

Ocean colour remote sensing is an important tool for environmental monitoring, especially involving climate change and anthropogenic impacts. Besides the chlorophyll a concentration (Chla) and the remote sensing reflectance (Rrs) of the oceans surface layers, new products, such as, the diffuse attenuation coefficient ((Kd(490)), Coloured Dissolved Organic Matter (CDOM) index, and particulate organic matter concentration (POC), have multiplied remote sensing applications for oceanographic researches. However, the estimation of these parameters in coastal zones, with optically complex waters, is still a great challenge. In this context, the present work aimed to evaluate the performance of MODIS-Aqua ocean colour products in coastal waters of Ubatuba (SP/Brazil), with in situ validation at the ANTARES-Ubatuba station. The station is characterized by a mixture of Case 1 and 2 waters. The Rrs (412, 443, 490, 510 e 555 nm) showed higher errors associated to the 412 and 443 nm bands, which have greatest challenges in the atmospheric correction. Anyway, the Chla and Kd(490) showed very good association with in situ data (R 2 = 0.81 and 0.82, respectively). The CDOM index did not work, because the dependency relationship between CDOM and Chla, used in the index model, wasnt encountered in the study area. Other models that derive the constituents separately (e.g. semi-analytical) should be tested for the CDOM retrieval. The POC, on the other hand, showed a reasonable performance (R2 = 0.44), with good potential of application for the Ubatuba coastal waters.Pages: 7168-717