RCAAP Repository

A western margin frontal zone is described, from measurements of temperature, salinity and currents, in a section taken with R/V "Prof. W. Besnard" in December 1980, crossing the shelf break border at latitude 26º30'S. The analyses of the sections showed consistently the occurrence of an ascension of the T and S isolines over the shelf break. Simultaneous current measurements showed a surface eddy structure with clockwise circulation and anti-clockwise circulation having a common stem over the break characterizing a shelf break upwelling.

Feeding behavior of immature green turtles, Chelonia mydas, has been observed on rocky shores along the northern part of State of São Paulo, southeastern Brazil. This turtle forages on underwater ledges, at depths of 1 to 3 m and grazes on benthic algae. The turtle seems to visually scan the algae during feeding and moves slowly, walking from one patch of vegetation to another. Gut contents of four individuals (331-452 mmCCL) consisted mainly of red and brown algae. Comparisons between gut contents and algae growing at the grazing sites, together with scanning behavior suggest selective feeding. Syntopic large herbivorous fishes of the genera Kyphosus, Sparisma, and Acanthurus showed little feeding overlap with the green turtle.

Levels of 0.123 0.60 and 2.20 of total DDT were found in three out of ten water samples of Santos Bay and estuarine region of Santos and São Vieente (SP).

The copepods of plankton samples collected with a Bongo net of 0.333 mm mesh in 66 oceanographic stations of 4 transects off the States of Rio de Janeiro (RJ) and Santa Catarina (SC) in Nov./Dec. 75 and May 76 were qualitatively and quantitatively studied. An amount of 173 species was identified, of which Paivella naporai Wheeler, Xanthocalanus marlyae Campaner, and Corycaeus giesbrechti F. Dahl were taxonomically reviewed. Frequency and density of each species, and absolute and mean density of total copepods were determined for every station, as well as frequency of adult females and males, and young forms. Abundance was higher in the neritic than in the oceanic zone, the mean density being twice greater of the neritic zone of RJ than in that of SC and almost identical in the oceanic zone off both States except for SC in Nov./Dec. 75, where values were thrice greater than in RJ. These results were related to the distribution of water masses in the sampling areas. Copepod associations were determined for neritic and oceanic zones off the States of RJ and SC at both sampling seasons.

Size compositions and total landings of skipjack tuna caught in the southeastern Brazilian waters by bait-boats are used as the basis of the assessment of the population for 1980-1983 period, employing the length cohort analysis and virtual population analysis. From monthly size frequency data it is suggested that there is constant immigration and emigration of different modal groups in the fishing area with an interval of two to three months. The exploitation rate was very low for length class between 35-45 cm FL, then increased gradually. The weighted mean exploitation rates were 0.060 and 0.448, respectively for length classes smaller and larger than 55 cmFL. The estimate of the average number of fish attaining a size of 43 cm FL (recruit) was 11.0 x 10(6) fish for assumed values of M - 0.7 and K = 0.307. Increasing the fishing mortality rate by 30% and 50%, an estimated increment in yield is 8% and 12%, respectively. From virtual population analysis, we obtained the biomass estimate of skipjack population older than two years-old to be 70.3 thousand tonnes for assumed value of M = 0.7 and the estimated MSY was 24.6 thousand tonnes.

Morphological changes in a sector of the State of São Paulo coastline, known as "Enseada de Caraguatatuba", were recognized through interpretation of air photographs in 1:25.000, 1:20.000 and 1:8.000 scales and field surveys done during the period November of 1978 to August of 1981. Grain size, shape, roundness and cluster analyses of 53 samples from the associated sedimentary deposits allowed us to characterize their textural properties, as well as to understand the coastal processes involved in the evolution of the area during the last years.

Five-nearly-synoptic spatial oceanographic observations, taken from January, 1970 to February, 1971, in the region between Cape of São Tomé and Guanabara Bay, are used to describe the seasonal circulation and flow conditions of the Brazil Current, close to the continental slope. The relative geostrophic velocities were calculated over isanosteric surfaces, according to the method suggested by Montgomery (1937). The precision of the method has been analysed, on the basis of the propagation of the instrumental errors for temperature, salinity and depth to the specific volume anomaly and acceleration potential, leading to a precision of about ± 3,0 cm s-1 for the relative speed, and a¹ maximum of ± 2,5 Sv, for the volume transport through a transversal section. The surface geostrophic currents, computed with reference to the isanosteric surface of the 100 cl ton-1 , are generally stronger through the sections east of Cabo Frio, where they reach maximum values (~90 cm s-1 on the edge of the continental shelf during the summer, and values up to 86 cm s-1 occur in the winter further offshore, at distances from the coast higher than 140 km. The T-S diagrams show the details of the flow distributions on characteristic classes and the fact that 50% of the net flow transports the Tropical Water Mass, above the 220 cl ton-1 isanosteric surface. The variations of the total transport flow in the water column, from the surface to the reference isanosteric surface, were analysed to estimate the transport-per-unit-width.

Oxidable POC, at two stations in the Cananéia estuary, was found to be largely dependent upon the smallest size POC. The correlation factors between POC and the numerical abundance of cells, heterotrofic particles and bacteria, in each of the size categories studied, were generally low and non-significant for both stations, with a few exceptions. At St. I the number of heterotrophic particles seems to account for some of the POC variation over the year. At St. II, the only significant correlation found was between the number of the largest and intermediate size classes bacteria and the equivalent size classes POC. At this station the importance of the detritus component is suggested. The differences found between the stations, concerning the numerical contribution of cells, particles and bacteria to total POC, have been attributed to the differential hydrodynamic conditions acting upon material coming from land, due to diverse location of the stations. Sampling date and the collection of different water masses have also been considered as factors that may greatly affect the relationships studied.

Primary growth was analysed on artificial substrata submerged at three sites of the Santos estuary (State of São Paulo, Brazil). Research on sessile ciliates was emphasized because they were the most conspicuous organisms of the primary growth developed along this estuary. Zoothamnium commune, dominated near the headwaters of the estuary, where the greatest amount of suspended matter in the water was found. Ephelota gemmipara dominated downstream. Although short time variability was observed in the colonization of substrata submerged on subsequent days, seasonal patterns could be determined. These patterns were characterized by a greater number of rare species of sessile ciliates, and a higher density of the most frequent ones, during spring and summer.

The objective of this work is to study the possibility of estimating the heat flux balance at the sea surface from GOSSTCOMP (Global Ocean Sea Surface Temperature Computation) developed by NOAA/NESS, USA, and sea surface current data based from ships drift information obtained from Pilot Charts, published by the Diretoria de Hidrografia e Navegação (DHN, Brazilian Navy). The annual mean value of the heat flux balance at the sea surface off southeast Brazil for 1977, is estimated from data on the balance between the heat transported by the currents and that transported by eddy diffusion for each volume defined as 2º x 2º (Lat. x Long.) square with a constant depth equivalent to an oceanic mixed layer, 100 m thick. Results show several oceanic areas where there are net flows of heat from atmosphere towards the sea surface. In front of Rio de Janeiro the heat flow was downward and up to 70 ly day-1 and is probably related to the upwellirug phenomenon normally occurring in that area. Another coastal area between Lat. 25ºS to 28ºS indicated an downward flow up to 50 ly day-1; and for an area south of Lat. 27ºS, Long. 040ºW - 048ºW an downward flow up to 200 ly day-1, where the transfer was probably due to the cold water of a nortward flux from the Falkland (Malvinas) Current. Results also show several oceanic areas where net flows of heat (of about -100 ly day-1) were toward the atmosphere. In the oceanic areas Lat. 19ºS - 23ºS and Lat. 24ºS - 30ºS, the flows were probably due to the warm water of a southward flux of the Brazil Current. The resulting fluxes from the warm waters of the Brazil Current when compared with those from warm waters of the Gulf Stream and Kuroshio, indicate that the Gulf Stream carries about 3.3 times and the Kuroshio 1.7 times more heat than the Brazil Current. These values agree with those of data available on the heat fluxes of the above mentioned Currents calculated by different methods (Budyko, 1974).

Characteristics of the structure and sea water properties on the continental shelf and waters adjacent to the continental slope, were studied based on the temperature-salinity (T-S) relationships. The water sampling was carried out with standard methods in a network of hydrographie stations worked in five-time intervals (5-10 days), from January 1970 through February 1971. The classification review of the water masses used under regional conditions confirm that the Subtropical-Deep (STDW), Subtropical (STW) and South Atlantic Central (SACW) Water Masses are different nomenclature for the same water mass; the latter is suggested to indicate a water mass with a thermohaline index given by (20.0 ºC; 36.36 ‰), observed underneath the Tropical Water Mass. This salinity value is slightly higher than the modified thermohaline index of the SACW (36.20 ‰), and can be used with great simplification in volumetric studies in the area. Polynomial expressions of the mean T-S curve, whose coefficients were computed with the least squares method, were given for practical applications. From these applications, alternative methods for the determination of the thermohaline derivative and constant density ratio (Rρ = αdT/βdS) were obtained.

In population studies based on genetic-biochemical markers, variations induced by ontogenetic development, sex and gonad maturation act as a potencial source of bias. These aspects were analysed for patterns of eye-lens proteins of Micropogonias furnieri (Sciaenidae), following electrophoregrams obtained from 546 specimens ranging from 98 and 710 mm in length, collected along the southeastern Brazilian coast (23º S - 29º21'S). Proteins were extracted in 0.9% NaCl solution, processed on cellulose acetate membranes in a bridge buffer discontinuous system trisglicine-barbital, for 25 minutes at 300 V, and stained with Ponceau S. The basic pattern obtained was divided into 4 sets and 8 fractions, that were evaluated by scanning in a ATAGO-QUICK densitometer. No differences were found in the patterns of right and left eye-lens, male and female and maturity stages for the same length class. Patterns variations related to ontogenetic development were found: set I present a decrease, while sets II, III and IV show an increase in their relative concentration. Set II showed two fractions for young (until 300-350 mm) and only one for adults. Fractions I, II-1, II-2, III-3 become stable above 300-350 mm and I and IV-2 above 450-500 mm length. For the utilization of this genetic-biochemical markers and according to the study purpose the comparison of fractions or patterns should consider: a - only fractions whose relative concentration were stable (III-1, III-2 and IV-1) or, b - only electrophoregrams from fishes of narrow total length range, whithout ontogenetic influence or, c - only patterns of individuals with total length above of which the fractions concentration become stable (II-2 and III-3 above 300 mm and/or I and IV-2 above 450 mm) or, d - only the basic patterns of the adults, when fractions number and relative concentration become stable. This last alternative (d) seems to be more appropriate either in interspecific studies when the aim is restricted to spacial populations delimitation, or in taxonomic studies, when there are no problems concerning to the classification of young forms.

Five stations were sampled monthly in the Bay of Paranaguá during one year cycle (1983-1984) to measure basic environmental parameters, phytoplankton biomass and photosynthesis with the purpose of understanding the principal factors that regulate the phytoplankton growth and distribution throughout the year. Surface temperature varied from 17 to 30ºC. The yearly average values for salinity, dissolved oxygen and pH ranged from 9.38 to 32.00‰, 5.17 to 5.53 ml/l and 7.46 to 8.18, respectively. Average concentrations of total inorganic nitrogen, phosphate and silicate varied from 3.31 to 8.48, 0.38 to 0.97 and 27.68 to 98.36 µg-at/l, respectively, with increasing concentrations toward the inner bay. Chlorophyll-a at the surface varied between 2.86 and 13.99 mg/m³ with high concentrations in the inner bay associated with high nutrient contents and lower salinities. Low photosynthetic rates were measured at the surface, varying from 0.01 to 7.36 mgC/m³/h. Phytoflagellates and Skeletonema costatum dominated the phytoplankton population during the study period. The temporal fluctuations in the inner bay are associated with the rainfall regime. High amounts of precipitation increase the concentrations of nutrients and consequently improve the phytoplankton growth. This is however limited by nitrogen deficiency (as indicated by the low N to P ratios observed) and turbidity.

Macrodon ancylodon was obtained from landings in Santos Port (São Paulo State) of fish caught monthly by commercial vessels, on the southern coast of Brazil during September 1976 to August 1977. The measurements of total lenght, total weight determination of sex and maturity stages were made. The food items found in stomach contents were: shrimp (Artemesia longinaris), fishes (Paralonchurus brasiliensis, Macrodon ancylodon, Trichirus lepturus, Gadidae, Engraulidae), molluscs (Loliginidae, Bivalvia) and Stomatopoda. Widening of food spectrum was observed in winter. The index of preponderance showed that immature females, immature and mature males fed predominantly on shrimp, while mature females fed mainly on fishes. During spring and summer (spawning season) M. ancylodon exhibited relatively low percentage of full stomachs. Cannibalism was encountered more intensively for mature fish.

A three-dimensional linear hydrodynamical numerical model, Heaps type, was developed and applied to the southeastern Brazilian continental shelf, to simulate motions in the sea due to astronomical and meteorological effects. The first experiment of the model reproduced the propagation of the principal lunar tidal component (M2), allowing the plotting of its cotidal lines and current ellipses. In the second experiment, the circulation generated by astronomical factors only was simulated. And in the third experiment, the effect of the principal astronomical tidal components and meteorological effects observed in the area were reproduced, representing the total circulation in the shelf, in a period of high tidal elevations in the coast, due to the incursion of a deep cold front in this region.

Feeding of males and females of the Gammaridea Hyate media at mature and immature stages were tested in laboratory experiments. Macro and microscopic algae as well as dead or alive animals were utilized as food. This gammarid is omnivorous, feeding by predation, scavenging, browsing and scraping. Feeding behaviour was discontinuous. Padina vickersiae was more utilized in winter and Ulva fasciata in summer. The feeding activity of all the animals showed great variability in relation to the type of food. Higher temperatures probably account for the higher consumption observed in summer.

A preliminary study was carried out on electropherograms of eye-lens, muscle proteins and zymograms of muscle esterases of ten Notothenia larseni, six Notothenia nudifrons and one lanternfish, Electrona antarctica. The fish were collected by the R/V "Prof. W. Besnard" of the Institute of Oceanography, University of São Paulo, during the First Brazilian Expedition to Antarctica. Eye-lens proteins were analysed on cellulose acetate membrane, muscle proteins and esterases on gel of polyaorylamide. Eye-lens proteins showed three types of electropherograms for N. larseni, and two types for N. nudifrons. One of the electropherograms of N. larseni can be readily distinguished from those of N. nudifrons. Electropherograms of muscle proteins of N. larseni and N. nudifrons are very similar and, consist of sixteen to seventeen fractions. Electropherograms of muscle proteins of N. larseni are severely affected by the conservation of the extracts overnight under -20ºC. All N. nudifrons were of the same zymograms of esterases while those of N. larseni varied. Electropherograms of eye-lens and muscle proteins as well as zymograms of esterases of the lanternfish are different from those of nototheniids.

The tidal analysis of data from the Equatorial region, given by inverted echo-sounders, show considerable residuals in the frequency band of approximately 2 cycles per day. In the even harmonics of 4 and 6 cycles per day, tidal components statistically not negligible are also identified. Spectral analysis of temperature series from the same area show, on the other hand, variabilities in the same frequency bands, which suggests the occurrence of internal waves with energy distributed in these frequency bands, in the Atlantic Equatorial area.

In the present paper 90.418 individuals belonging to 186 species of fish were examined. The samples were taken on the southeastern Brazilian shelf, from Cabo de São Tome (RJ) (22º21'S) to Torres (RJ) (29º21'S) - Brazil. The present results indicate the presence of 12 different parasitic species of Cymothoidae and 13 host-species of fish. A high degree of specificity between Cymothoa sp1** and the host, Chloroscombrus chrysurus (Pisces, Carangidae) was disclosed. Although Lironeca redmanni is not specific-parasite, it was found mainly on Cynoscion striatus (Pisces, Sciaenidae).

Environment-zooplankton relationships were analysed in Maldonado Bay (Uruguay), an estuarine area between the River Plate and the Atlantic Ocean. This was done through Principal Component Analysis. Most of the environment variability is accounted for, primarily, by the outflow of the River Plate and the inflow of coastal waters which change through the annual cycle, and in the second place by surface water conditions. On the other hand, most of the zooplankton variability is accounted for by 17 taxa abundant in April and February and by one dominant species present only from May to August. A second source of zooplanktonic variability is due to species which occurred in fall only The main observed variabili ty occurred on an annual scale. On it, variations on smaller scales overlap: from one day to another, between Maldonado Bay and the adjacent waters of the River Plate. The main factors involved were different at each scale. The Bay is relatively isolated from adjacent waters, but the degree of isolation varies throughout the year. The influence of coastal water is greater and occurs first outside the Bay. Biological processes may develop under different conditions in the Bay and in the adjacent waters of the River Plate.