Dinoflagelados (pyrrhophyta) del archipiélago los Roques (Venezuela): familias prorocentraceae y ostreopsidaceae / Dinoflagellates (pyrrhophyta) from the los Roques archipielago (Venezuela): families prorocentraceae and ostreopsidaceae

Se examinaron muestras provenientes del Parque Nacional Archipiélago Los Roques, en el Mar Caribe Sur-Oriental (Venezuela), mediante microscopía óptica. Se describen quince (15) especies de dinoflagelados (Pyrrhophyta) pertenecientes a las familias Procentraceae y Ostreopsidaceae. Los símbolos (*) y (**) señalan nuevos registros para Venezuela y el Mar Caribe respectivamente. Se encontraron diez especies para Prorocetraceae: Mesoporos perforatus (Gran) Lillick, Prorocentrum compressum (Bailey) Abé ex Dodge, *Prorocentrum concavum Fukuyo, *Prorocentrum emarginatum Fukuyo, *Prorocentrum gracile Schütt, Prorocentrum lima (Ehrenberg) Dodge, Prorocentrum micans Ehrenberg, *Prorocentrum rhathymun loeblich III, Sherley & Schmidt, *Prorocentrum scutellum Schröder y Prorocentrum triestinum Schiller. En Ostreopsidaceae se encontraron cinco especies: Coolia monotis Meunier, *Gambierdiscus toxicus Adachi&Fukuyo, ** Ostreopsis lenticularis Schmidt, *Ostreopsis ovata Fukuyo y **Ostreopsis siamensis Schmidt. Finalmente se presenta una clave para las especies Prorocentrum y Ostreopsis encontradas en este estudio.

Estrutura da comunidade fitoplanctônica da lagoa de Juturnaíba, Araruama, RJ, Brasil: uma comparaçäo entre o centro da regiäo limnética, tributários e canal de drenagem / Structure of phytoplankton community of lagoa de Juturnaíba, Araruama, RJ, Brazil: a comparison between centrum of limnetical region, tributaries and drainage channel

Foi comparada a estrutura da comunidade fitoplanctônica da regiäo limnética da Lagoa, com seus tributários e seu canal de drenagem. A composiçäo florística, diversidade, equitabilidade, abundância e análise qualitativa da afinidade, mostraram maiores semelhanças entre o centro da Lagoa e seu canal de drenagem, sendo estes diferenciados dos tributários. A análise quantitativa da afinidade separou os ambientes em funçäo das concentraçöes das populaçöes de algas, e evidenciou a formaçäo de grupos de espécies abundantes, onde destacam-se o grupo de espécies de Oscillatoria, exclusivo das estaçöes lóticas, e o grupo de espécies que apresentam uma maior adaptaçäo às variaçöes ambientais

Ficoflórula do açude de Apipucos (Recife-PE) / Ficoflorula of the Apipucos reservoir (Recife-PE)

O Açude de Apipucos está localizado na área urbana do Recife, há anos vem sofrendo efeito da eutrofizaçäo artificial, pois recebe freqëntemente despejos, principalmente de natureza orgânica, tais como, esgotos e lixo domiciliares. A Ficoflórula está distribuída em 4 (quatro) Divisöes, 12 (doze) Ordens, 48 (quarenta e oito) gêneros, 36 (trinta e seis) espécies, 10 (dez) variedades e 3 (três) formas. A ordem Chlorococcales foi a melhor representada, tanto em termos qualitativos e quantitativos. Cerca de 95% das espécies identificadas säo características de águas eutróficas

Further use of fluorochromes in the cytochemical characterization of phytoplankton.

The rapid, specific effects of 25 fluorochromes at low concentration and physiological conditions of pH and temperature were investigated on live cells of five phytoplankton species (Prorocentrum micans, Amphidinium carterae, Dunaliella tertiolecta, Chlamydomonas moewusii and Fragilaria crotonensis). They allowed the identification of cellular components such as the plasma membrane, endoplasmic reticulum, Golgi apparatus, thecal plates, nucleus, mitochondria, trichocysts, vacuoles/lysosomes, polyphosphate and starch granules, lipid bodies and hydrolytic enzymes. Morphological alterations of some of these constituents were examined in cells at different metabolic states. It was found that the thickness of Prorocentrum thecal plates increases during cell development while surface pores appear to be formed in the early stages of thecal formation. The number and size of mitochondria varies among cells at different stages of growth. The number of trichocysts, the size of vacuoles and the quantity of polyphosphates, starch or lipid inclusions increases in nitrogen-depleted cells. Photodegradation and photoenhancement phenomena are described. Some important factors helping to avoid quenching and some applications of the fluorochroming technique are presented.

Estudo qualitativo do fitoplâncton da represa de Serraria, Estado de Säo Paulo, Brasil / Qualitative study of phytoplankton from Serraria reservoir, state of Säo Paulo, Brazil

Durante o ano de 1979, foram realizadas coletas para o estudo qualitativo do fitoplâncton da Represa de Serraria, Estado de Säo Paulo, Brasil. Em cada coleta foram obtidas com garrafa Van Dorn, 6 amostras, nas profundidades correspondentes a 100, 50, 25, 10, 1 e 0% (zona afótica) de penetraçäo de luz, além de mais duas amostras, coletadas em toda d'água com redes de 20 e 53 micronm de abertura de malha. Foram identificados 108 táxons, sendo 45 de Chlorophyceae, 18 de Cyanophyceae, 18 de Zygnemaphyceae, 8 de Euglenophyceae, 6 de Diatomophyceae, 6 de Dinophyceae, 5 de Chrysophyceae, 1 de Oedogoniophyceae e 1 de Xanthophyceae. Uma nova forma de Staurastrum ellipticum W. West foi descrita neste trabalho

Analysis of phytoplankton by flow cytometry.

Optical properties of eight algae species were measured on a flow cytometer. Forward and perpendicular light scatter measurements provide information on the size and shape of algae cells. The intensity of chlorophyll fluorescence varies greatly among the studied algae species and can be used to distinguish them. Measurements of chlorophyll fluorescence after excitation with different wavelengths provide a fluorescence excitation spectrum for each species over the available wavelength range. These spectra reflect the different photosynthetic pigment contents of the species. Staining algae cells with the DNA stains, Hoechst 33342 and DAPI, provides two additional optical parameters to distinguish algae populations: blue nuclear fluorescence and yellow granular fluorescence. The combination of these optical measurements enables the distinction of each algae species into a small cluster in a hyperspace of parameters. The automation of phytoplankton analysis on the flow cytometer may lead to the rapid and objective assessment of water quality.

Molecular weight fractionation of dissolved organic matter (DOM) released by phytoplankton.

The application of an ultrafiltration procedure for fractionation of molecular weight of dissolved organic matter (DOM) extracellularly released by phytoplankton is described. Seven ultrafiltration membranes Diaflo (Amicon Corp. USA), with range 500--300,000 molecular weight (MW), were used for separation of different molecular weight compounds released by phytoplankton in Rhode River estuary of Chesapeake Bay, and their composition was determined. Percentage of extracellular release of DOM by phytoplankton varied from 3.92--68.07% of total carbon fixed in photosynthesis. The composition of algal extracellular products varied with different phytoplankton populations. However, two fractions of molecular weight compounds dominated in the composition of DOM released, i.e. a low molecular weight fraction of less than 1,000 MW and the fraction between 10,000--30,000 MW. The ultrafiltration procedure is effective for studying the composition of DOM released by phytoplankton in natural waters.

Preliminary study of the occurrence and distribution of DDT residues in the Jordan watershed, 1971.

Data obtained from the Jordan watershed in 1971 revealed the presence of DDT and its metabolites at various levels along the food chain. Detectable levels of sigmaDDT in water of the Jordan River and two fish ponds ranged from 0.019 to 0.500 ppb, which is 1/10 to 1/500 the maximum level permitted in water by the U.S. Government. Mean residue in phytoplankton was 0.906 mug/g; in zooplankton the mean was 6.49 mug/g. SigmaDDT residue in fish of the Jordan watershed averaged 0.37 mg/kg in carp, 2.59 mg/kg in benith, and 3.34 mg/kg in sardines.