Studies on Cyclotella meneghiniana Kutz III. The frustule

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On Camptylonema indicum Schmidle and Camptylonemops is gen. nov.

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Electron microscopy and algology

Since 1936, when the first alga was investigated with the help of the Electron Microscope more and more algae have been studied. These studies have greatly contributed to our knowledge of the submicroscopic morphology of algae. A review of the most important aspects of these investigations is given in this paper. The utilization of the results of these Electron Microscopic investigations in taxonomy is discussed

Taenioma J. Ag. from India

Both the known species of Taenioma, T. perpusillum J. Ag. and T. nanum (Kuetz.) Papenfuss, are here reported for the first time from India. General features of thallus organisation in both species are described in detail. The development of tetrasporangia in T.Perpusillum is described. In general, the writers' observations are in agreement with those of Papenfuss. The taxonomy of the genus is discussed and the authors agree with Papenfuss in keeping the two species distinct

Mastigocladopsis jogensis gen. et sp. nov., a new member of the stigonemataceae

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Effects of increased salinity on the diatom assemblage in Fonda Lake, Michigan

A salt storage facility has been located adjacent to Fonda Lake since 1953. In February 1981 a core was taken from the profundal sediments of the lake and analyzed to determine the effects of salt perturbation on the diatom community over a 32-year period. Diatom assemblages from different levels were compared using multivariate techniques including cluster analysis and principal component analysis. Shifts in diatom composition related to salinification were revealed most clearly by subdominant taxa. Five distinct groups of diatom taxa were found to correspond with 5 depth intervals. The diatom component of the lake up to 1960 included two groups of taxa which were alkaliphilous and chloride indifferent. A reduction in species diversity beginning in 1960 may indicate a salt effect. By 1968, when diversity reached a minimum, a variety of halophilic taxa (including Diatoma tenue, Navicula gregaria and Synedra fasciculata ) attained their highest relative abundances. At the top of the core, diversity increased slightly and some halophilic taxa decreased in relative abundance, which suggests a possible decrease in salt loading to the lake.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42866/1/10750_2004_Article_BF00011577.pd

SEASONAL ASSESSMENT OF HYDROGRAPHIC VARIABLES AND PHYTOPLANKTON COMMUNITY IN THE ARABIAN SEA WATERS OF KERALA, SOUTHWEST COAST OF INDIA

The seasonal variation of the hydrographic variables and phytoplankton species in the Arabian Sea waters of the Kerala coast, Southern India was investigated during different seasons. The variables such as pH, temperature, salinity, turbidity and chlorophyll-a contents of water were found to be high during pre-monsoon season and the dissolved oxygen content was minimal. The concentration of nutrients viz., nitrate, phosphate, silicate varied independently. In the study a total of 53 species of phytoplankton were recorded. Their density was higher during the post-monsoon season than during other seasons and the diatoms were found to be the dominant species. The major phytoplankton in terms of frequency and abundance were the species namely, Biddulphia mobiliensis, Chaetoceros curvisetus, Licmophora abbreviata, Skeletonema costatum, Prorocentrum micans and Oscillatoria sp. They showed significant positive correlation with pH, temperature, salinity, nitrate, phosphate and chlorophyll-a contents, whereas turbidity, dissolved oxygen and silicate exhibited significant negative correlation. The Principal Component Analysis (PCA) developed two principal components with 84.74% of total variability in the water quality which separated pre- and post-monsoon periods from the monsoon season on axis I, and pre-monsoon and monsoon periods from post-monsoon on axis II

Remarks on the morphology and distribution of some rare centric diatoms in southern Brazilian continental shelf and slope waters

This paper provides information on the morphology and occurrence of extant diatoms of the family Asterolampraceae and Azpeitia species of the southernmost Brazilian continental shelf and slope waters in the Southwestern Atlantic Ocean (28 -34ºS), under the influence of Tropical, Subtropical, Subantarctic Waters, terrestrial discharges from La Plata River and Lagoa dos Patos lagoon. Plankton was sampled (20 µm net; vertical hauls) at the same 27 stations in winter 2005 and summer 2007. Among Asterolampraceae, Asteromphalus flabellatus was the most frequent species (57% of samples) observed mainly in winter samples (92%) in Subtropical Shelf Water but also under the influence of La Plata River plume (salinity O trabalho apresenta informações morfológicas e sobre a ocorrência de diatomáceas atuais da família Asterolampraceae e de espécies de Azpeitia encontradas na plataforma continental e talude do extremo sul do Brasil no Oceano Atlântico Sul (28 -34ºS), sob influência de Águas Tropical, Subtropical e Subantártica, bem como do aporte terrestre do Rio La Plata e da Lagoa dos Patos. O plâncton foi amostrado (rede de 20 µm; arrastos verticais) em 27 estações de coleta no inverno de 2005 e verão de 2007. Entre as Asterolampraceae, Asteromphalus flabellatus foi a espécie mais freqüente (57% das amostras), principalmente nas amostras de inverno (92%) em água Subtropical de Plataforma, mas também sob influência da pluma do Rio La Plata (salinidade <35). Asterolampra marylandica, Asteromphalus elegans, Asteromphalus heptactis and Spatangidium arachne ocorreram em menor frequência. Quatro espécies de Azpeitia foram observadas: A. barronii e A. neocrenulata, são citadas pela primeira vez para o Oceano Atlântico Sul, enquanto A. africana e A. nodulifer, já foram reportadas em áreas equatoriais e meridionais brasileiras. Todas as espécies de Azpeitia foram raras (19%) nas amostras de alto-mar (entre as isobatas de 100-200 m). Considerações sobre a morfologia baseada em observações ao microscópio óptico e eletrônico de varredura são fornecidas juntamente com dados de distribuição das espécies na área estudada

Phytoplankton dynamics in a highly eutrophic estuary in tropical Brazil

The port of Recife in northeastern Brazil is an important ecological and social area but little is known about its environmental quality. Observations, sampling and measurements of phytoplankton were performed during spring and neap tides in the dry (January-February, 2005) and rainy (June, 2005) seasons to assess the environmental quality of the port of Recife. The area had chlorophyll-a concentrations ranging from 3.30 to 54.40 mg m-3, the highest values occurring at low tide during the dry season. A total of 129 species were identified: 53 of them in the dry season and 97 in the rainy season. Diatoms were the most diverse group and comprised 75.47% of the phytoplankton collected in the dry season and 60.82% of those collected in the rainy season. The dry season was characterized by Coscinodiscus sp. and Helicotheca tamesis; the rainy season by Oscillatoria sp. and Coscinodiscus centralis. Species diversity indices varied from 1.06 to 3.74 bits cel-1. Low indices were related to the dominance of Helicotheca tamesis, Coscinodiscus centralis, Coscinodiscus sp. and Aulacoseira granulata. Seasonal forcing, rather than the estuarine flux, determined the phytoplankton community structure. The area is exposed to seasonally varying negative impacts due to metropolitan degradation and the high level of eutrophication.Para avaliar a qualidade ambiental Porto do Recife (Nordeste do Brasil), uma área ecológica e socialmente importante mas pouco investigada, observações, medições e amostragem do fitoplâncton foram realizadas durante as marés de sizígia e quadratura no período de estiagem (janeiro-fevereiro / 2005) e chuvoso (junho/2005). A área apresentou concentração de clorofila a variando de 3,30 a 54,40 mg m-3, com maiores valores registrados durante a maré baixa no período de estiagem. Um total de 129 espécies foi identificada com 53 espécies durante o período de estiagem e 97 espécies no chuvoso. As diatomáceas formaram o grupo mais diverso, com 75,47% no período de estiagem e 60,82% no chuvoso. Coscinodiscus sp. e Helicotheca tamesis caracterizaram o período de estiagem e Oscillatoria sp. e Coscinodiscus centralis o período chuvoso. A diversidade de espécie variou de 1,06 a 3,74 bits cel-1 . Os baixos índices foram relacionados com a dominância de Helicotheca tamesis, Coscinodiscus centralis, Coscinodiscus sp. e Aulacoseira granulata. A sazonalidade determinou a estrutura da comunidade fitoplanctônica, em vez do fluxo estuarino. A área é exposta sazonalmente a vários impactos negativos, devido à degradação metropolitana e ao elevado nível de eutrofização