Flávia Marisa Prado Saldanha-Corrêa

Instantaneous transport of salt, nutrients, suspended matter and chlorophyll-a in the tropical estuarine system of Santos

The contribution of the polluted Sao Vicente and Santos estuarine channels to the eutrophication of Santos bay was assessed through the quantification of instantaneous transport of salt, dissolved inorganic nitrogen (DIN) and phosphate, organic and inorganic matter (OSM and ISM) and chlorophyll-a (Chl-a), during dry (austral winter- August/ 1999) and rainy (austral summer- January/2000) seasons. Samplings were carried out during spring and neap tides, in flood and ebb phases, in two transversal sections at the mouths of the Sao Vicente and Santos channels. Instantaneous transport values generally indicated importation of salt to the estuarine channels, exportation of DIN to the bay, mainly as N-NH4, at a maximum rate of 1155.1 g s-1 during the rainy season; importation of phosphate during the dry season (maximum of 385 g s-1) and exportation of ISM, OSM and Chl-a during periods of greater freshwater discharge. These results demonstrate the great contribution made by the Santos and Sao Vicente estuaries to the eutrophication of Santos bay, especially in the rainy season.

Trichodesmium erythraeum Bloom on the Continental Shelf off Santos, Southeast Brazil

Samplings were undertaken on the basis of a grid of 40 oceanographic stations distributed along eight sections with the same point of origin: in the middle portion of the mouth of Santos Bay (Fig. 1). Surface water samples were collected using a Niskin bottle. The water samples were filtered through AP-40 Millipore filters for chlorophyll-

Assessment of plankton community and environmental conditions in São Sebastião Channel prior to the construction of a produced water outfall

A comunidade planctonica e condicoes hidrologicas foram avaliadas como parte de um diagnostico ambiental no Canal de Sao Sebastiao, previamente a construcao de um emissario submarino de agua de producao, oriunda do terminal maritimo da PETROBRAS. As amostras foram coletadas em vinte estacoes oceanograficas situadas na area adjacente ao terminal petrolifero, durante a primavera de 1991. As concentracoes de nutrientes inorgânicos dissolvidos e de cIorofila-a obtidas, indicam um ambiente oligo-mesotrofico. Fenois e sulfetos nao foram detectados e os valores de 080, com excecao de tres pontos, foram caracteristicos de ambientes nao poluidos, apesar da contaminacao por oleos e graxas ter sido observada em metade das estacoes amostradas. O fito e o zooplâncton apresentaram altos indices de diversidade e equitatividade para toda area estudada. O fitoplâncton foi dominado por fitoflagelados, enquanto que o zooplâncton foi dominado por copepodos, especialmente Paracalanus quasimodo. A composicao da comunidade planctonica foi similar a de outras areas adjacentes, sob baixa pressao aotropogenica.

A microcosm approach on the potential effects of the vertical mixing of water masses over the primary productivity and phytoplankton biomass in the southern Brazilian coastal region

The vertical mixing between South Atlantic Central Water (SACW) and Coastal Water (CW) was simulated through microcosm experiments using the autochthonous phytoplankton community (fraction 20°C) and oligotrophic. The phytoplankton growth potential of SACW, CW and an equivalent mixture of both (SACW+CW) was compared, under 100, 30 and 10% of sunlight, at surface seawater temperature, in winter and summer conditions. Results demonstrate the importance of SACW as a natural eutrophication agent for the mixing layer, allowing the occurrence of new production by nutrient input, and also as a biological seeder through the development of its autochthonous phytoplankton community when it reaches the euphotic zone. The time lag for phytoplankton development during winter was around 4-5 days, against 1-2 days in summer. The hypothesis of physiological differences between surface and bottom phytoplankton populations from a deep (80 m) and thermally homogeneous water column (common winter feature) was also tested through the microcosm experiments. Results obtained clearly demonstrate that bottom water presented higher phytoplankton growth potential than the surface one.

Short-term variability and transport of nutrients and Chlorophyll-a in Bertioga Channel, São Paulo State, Brazil

Short-term variability of nutrients, chlorophyll-a (Chl-a) and seston (TSS) concentrations were followed up at a fixed station in the Bertioga Channel (BC), Southeastern Brazil, over two full tidal cycles of neap and spring tides, during the winter of 1991. Simultaneous data on hydrographic structure, tidal level and currents allowed the computation of the net transport of those properties. Tidal advection and freshwater flow were the main forcing agents on the water column structure, nutrient availability and Chl-a distribution. Dissolved inorganic nitrogen and phosphate average values were high (16.88 and 0.98 ¼M, respectively, at neap tide and 10.18 and 0.77¼M at spring tide). Despite N and P availability, Chl-a average values were low: 1.13 in the neap and 3.11 mg m-3 in the spring tide, suggesting that the renovation rate of BC waters limits phytoplankton accumulation inside the estuary. The highest Chl-a was associated with the entrance of saltier waters, while the high nutrient concentrations were associated with brackish waters. Nutrients were exported on both tides, TSS and Chl-a were exported on the spring tide and Chl-a was imported on the neap tide. The study of the main transport components indicated that this system is susceptible to the occasional introduction of pollutants from the coastal area, thus presenting a facet of potential fragility.

On the determination of a conversion factor from labelled thymidine incorporation by bacteria to cell production in a sub-tropical estuary: preliminary results

Faculdade de Ciencias Ambientais - Oceanografia. Centro Universitario Monte Serrat - UNIMONTE. (Campus Ponta da Praia, Av. Saldanha da Gama, 89, 11030-220, Santos, SP, Brasil) Bacterial carbon production has become a key parameter in quantifying carbon flows through aquatic food webs (Smith & Azam, 1992). Measurement of

A comparison of the retention capability among three different glass-fiber filters used for chlorophyll-a determinations

Instituto Oceanografico da Universidade de Sao Paulo (Praca do Oceanografico, 191 05508-900, Sao Paulo, SP, Brasil) *fsalcorr@usp.br Chlorophyll-a (Chl-a) is a ubiquitous photosynthetic pigment in phytoplanktonic species, which include eukaryotic and prokaryotic organisms (cyanobacteria). Thus it has been used commonly as a reliable proxy for total phytoplankton biomass (Gregor & Marsalek, 2004) since the early 1930s (Phinney & Yentsch, 1985). Glass fiber filters have traditionally been used to concentrate phytoplankton cells to extract the pigments for spectrophotometric measurements. However, after the discovery of photoautotrophers smaller than 1 µm, such as cyanobacteria (Waterbury

Nephroselmis viridis (Nephroselmidophyceae, Chlorophyta), a new record for the Atlantic Ocean based on molecular phylogeny and ultrastructure

Nephroselmis is composed by unicellular nanoplanktonic organisms, occurring predominantly in marine environments. Currently, 14 species are taxonomically accepted. Nephroselmis viridis was described in 2011 and strains were isolated from Indic and Pacific Oceans. Since then, it was not recorded in other places. A strain was isolated from coastal waters of Brazil by micropipetting and washing, and cultivated in f/2 medium for morphological observations (light, confocal, SEM and TEM) and molecular phylogeny inferences (maximum likelihood and Bayesian). The cells are asymmetrical, have two unequal flagella, one cup-shaped chloroplast with an eyespot, and a large starch covered pyrenoid. Chloroplast thylakoids intrude into the pyrenoid and organic scales cover all cell body and flagella. Molecular phylogeny (18S rRNA) clustered the isolated strain with other Nephroselmis viridis sequences, and the species is the sister of the N. olivacea, the type species of the genus. Morphology and molecular phylogeny corroborate the strain identification, and it is the first time this species is recorded in Brazil and in the Atlantic Ocean.