Inés Sunesen

The diatom genus Thalassiosira: species from the northern San Matias Gulf (Rio Negro, Argentina)

This study deals with the morphology, taxonomy and distribution of species belonging to the diatom genus Thalassiosira found in the marine waters along the northern coast of San Matias Gulf, Argentina. Net samples were collected from the surface layer of the water column at Punta Orengo, Las Garzas, Banco Reparo, Los Alamos, Las Grutas, Piedras Coloradas, Bajo de Oliveira and El Fuerte from April 1998 to February 2000. Untreated and cleaned diatom samples were examined by light and scanning electron microscopy. Eighteen taxa were identified. T. frenguelliopsis is reported for the first time after its original description. T. mediterranea is a new record for the southwestern Atlantic Ocean, T. mala is a new record for Argentina, and T. angulata, T. endoseriata, T. hendeyi, T. nanolineata, T. pacifica and T. proschkinae are new records for Patagonia. Descriptions, illustrations, analysis of valve morphology and distribution are provided for the species not previously studied in detail from Argentinian coastal waters. New observations on T. frenguelliopsis and comparisons with related species known to have, or suspected of having, a similar ultrastructure are also included.

Marine diatoms from Buenos Aires coastal waters (Argentina). V. Species of the genus Chaetoceros

El genero Chaetoceros es un componente importante del plancton marino, de amplia distribucion mundial en terminos de diversidad y biomasa. El presente trabajo esta abocado a la morfologia, taxonomia y distribucion de las especies pertenecientes al genero Chaetoceros encontradas en aguas costeras marinas de la Provincia de Buenos Aires, Argentina. Las muestras fitoplanctonicas fueron recolectadas desde noviembre de 1994 hasta septiembre de 2000 en siete estaciones ubicadas a lo largo de la costa bonaerense entre los paralelos 36o20� y 37°20� S. El material fue estudiado con microscopia optica y electronica de barrido. Veinte taxa fueron encontrados, identificados, descriptos, ilustrados y comparados con los taxa mas allegados. Tres de esos taxa pertenecen al subgenero Chaetoceros (= Phaeoceros) y los restantes diecisiete pertenecen al subgenero Hyalochaete. Chaetoceros filiferus y C. compressus var. hirtisetus son reportados por primera vez para el Oceano Atlantico sudoccidental. C. danicus, C. debilis, C. lorenzianus y C. socialis, mencionadas como especies nocivas en otras areas geograficas, no fueron asociados a eventos nocivos en el area de estudio durante este periodo.

Cocconeis Ehrenberg and Psammococconeis García (Bacillariophyta) from the Gulf of San Matías, Patagonia, Argentina

The morphology and taxonomy of species of the genera Cocconeis Ehrenberg and Psammococconeis Garcia from the Gulf of San Matías (Patagonia, Argentina) is documented in the present study. A total of 16 taxa of Cocconeis and one species of Psammococconeis were found in surface net hauls taken in shallow coastal waters of the Gulf. Cocconeis fluminensis var. fluminensis, C. fluminensis var. subimpleta, C. guttata, C. peltoides and C. neothumensis var. marina are new records for the southwestern Atlantic Ocean.

Dinophysis spp. asociadas a detección de toxinas diarreicas (DSTs) en moluscos y a intoxicación diarreica en humanos (Provincia de Buenos Aires, Argentina)

During January and February 2010 lipophilic shellfish toxins were detected in two bivalve species from Villa Gesell and Mar Azul (Argentina) by the mouse bio...

Marine diatoms from Buenos Aires coastal waters (Argentina). II. Thalassionemataceae and Rhaphoneidaceae

Este estudio describe la diversidad de especies de diatomeas pertenecientes a las familias Thalassionemataceae Round and Rhaphoneidaceae Forti encontradas frecuentemente en aguas costeras marinas de la Provincia de Buenos Aires, Argentina, entre octubre de 1994 y septiembre de 2000. En el se lleva a cabo el estudio morfologico, taxonomico y distribucional de las especies halladas en muestras planctonicas colectadas en San Clemente del Tuyu, Santa Teresita, La Lucila del Mar, Mar de Ajo, Nueva Atlantis, Pinamar y Villa Gesell. Material sin tratar y tratado fue analizado con microscopio optico y microscopio electronico de barrido. Cuatro taxa de Thalassionema Grunow ex Mereschkowsky amend. Hallegraeff, uno de Lioloma Hasle, dos de Delphineis Andrews y uno de Rhaphoneis Ehrenberg, fueron identificados. Thalassionema pseudonitzschioides (Schuette & Schrader) Hasle, Thalassionema synedriforme (Greville) Hasle y Lioloma pacificum (Cupp) Hasle in Hasle & Syvertsen son reportadas por primera vez para aguas costeras de Argentina

Marine diatoms from Buenos Aires coastal waters (Argentina). IV. Rhizosolenia s. str., Neocalyptrella, Pseudosolenia, Proboscia

I. Sunesen & E.A. Sar 2007. Marine diatoms from Buenos Aires coastal waters (Argentina). IV. Rhizosolenia s. str., Neocalyptrella, Pseudosolenia, Proboscia. Phycologia 46: 628–643. DOI: 10.2216/07-13.1 The present paper describes the morphology, taxonomy, and distribution of species belonging to the diatom genera Rhizosolenia s. str., Neocalyptrella, Pseudosolenia and Proboscia, found in the marine coastal waters of Buenos Aires Province, Argentina. The phytoplankton samples were collected from October 1994 to September 2000 at seven locations and were analyzed by light and scanning electron microscopy. Rhizosolenia antennata f. antennata, R. bergonii, R. hyalina, R. imbricata, R. setigera f. setigera, R. setigera f. pungens, Neocalyptrella robusta, Pseudosolenia calcar-avis, Proboscia alata and P. indica were studied and compared with allied taxa. Morphology of the frustule and of the resting spore of R. setigera, which is considered by some authors incerta sedis, shows that this species might be included into the genus Rhizosolenia s. str. Rhizosolenia hyalina is reported for the first time from Argentinean coastal waters. R. setigera f. setigera, R. setigera f. pungens, P. alata, and P. calcar-avis, cited as harmful non-toxigenic taxa in other geographical areas, were never associated with harmful events in the study area.

Thalassiosira fryxelliae nov. spec. (Bacillariophyceae) from Argentinian coastal waters

Abstract The new marine nanoplanktonic diatom, Thalassiosira fryxelliae, is described with light and scanning electron microscopy from material collected in Argentinian coastal waters. T. fryxelliae is a morphologically distinctive species with: 1) cells embedded in irregular gelatinous masses, 2) absence of central, sub-central and scattered strutted processes on the valve surface, 3) one marginal ring of strutted processes with external tubes, 4) one marginal labiate process included in the ring of the strutted processes, 5) areolation pattern variable linear, sublinear, eccentric or irregular. Externally, the marginal strutted processes have double tubes, at least in the distal part, cut distally and with the half-cylinder bent vertically with crenulated distal edges and the labiate process has a simple tube. Internally, the strutted processes are short with four operculate satellite pores and the labiate process is sessile and radially located. Thalassiosira fryxelliae is similar to T. angulata and T. nanolineata in morphology and distribution pattern of the marginal strutted processes and in the location of the labiate process and to T. leptopus and some specimens of T. guillardii and T. pseudonana in lacking one central strutted process.

Diatomeas marinas de aguas costeras de la provincia de Buenos Aires (Argentina).: III Géneros potencialmente nocivos Asterionellopsis, Cerataulina, Ceratoneis y Leptocylindrus

El presente trabajo esta abocado al estudio morfologico, taxonomico y distribucional de las especies de diatomeas pertenecientes a los generos Asterionellopsis, Cerataulina, Ceratoneis y Leptocylindrus halladas en aguas costeras marinas de la provincia de Buenos Aires, Argentina. Las muestras planctonicas fueron colectadas en San Clemente del Tuyu, Santa Teresita, La Lucila del Mar, Mar de Ajo, Nueva Atlantis, Pinamar y Villa Gesell, entre noviembre de 1994 y septiembre de 2000. Material sin tratar y tratado fue analizado con microscopio optico y microscopio electronico de barrido. Seis taxa correspondientes a los generos mencionados fueron determinados, de los cuales Cerataulina dentata es citada por primera vez para Argentina y Leptocylindrus minimus es citada por primera vez para el area costera de la provincia de Buenos Aires. Todas las especies reportadas como nocivas no toxigenas para otras areas geograficas fueron encontradas. Cerataulina pelagica, Ceratoneis closterium y Leptocylindrus minimus, componentes ocasionales del plancton del area siempre en bajas densidades, no fueron nunca asociadas a episodios de floracion. Asterionellopsis glacialis, componente habitual del plancton, fue causante de discoloraciones nocivas para el turismo y las actividades recreacionales

Studies on Amphora subgenus Halamphora (Bacillariophyta): the revision of some species described by Hustedt using type material

As part of an analysis of type material of Amphora species described by Hustedt, the lectotypes of Amphora fontinalis, A. rugosa and A. schroederi and the holotype of A. subturgida were analysed. Light microscopy showed that all these tropical freshwater taxa are similar in frustule and valve outline, position of the raphe, appearance of the dorsal striae and thickening of the central dorsal virgae. Scanning electron microscopy allowed reliable differentiation between the four, based on the morphology of dorsal striae, dorsal areolae, conopeum, proximal raphe fissures, presence or absence of an inner longitudinal rib close to the raphe sternum, and degree of thickening of the central dorsal virgae. Previous reports of A. fontinalis from Tahiti and Moorea were confirmed while reports of this species from Australia and of A. subturgida from Mauritius, Papua and Israel were refuted. Based on our results, species descriptions are emended and the distributions of these four species are revised. Comparisons of these species and others of the subgenus Halamphora are presented.

AN EMENDED DESCRIPTION OF AMPHORA TUMIDA HUSTEDT (BACILLARIOPHYCEAE)

Material chosen as the lectotype of Amphora tumida Hustedt by Simonsen was examined with light and scanning electron microscopy. Based on this analysis a more comprehensive concept of this taxon was established and the description emended. A comparison with the morphologically similar A. subacutiuscula Schoeman and A. acutiuscula Kützing sensu Archibald strongly suggests that A. tumida is present in South African waters, in addition to its confirmed records from Venezuela and Argentina.