Planktonic dinoflagelltes cysts in areas from the southwestern atlantic shelf: I. Taxonomic report on the Peridiniacace ehreber

This work constitutes a first contribution to the taxonomy of dinoflagellate resting cysts in planktonic samples of this region, being studied nine species of Protoperidinium Bergh and Zybabikodinium Loeblich Jr. et Loeblich III of the family Peridiniaceae. Incubation experiments with living material and parental thecae containing resting cysts in fixed samples allowed setting up of the cyst-theca relationship in P. obtusum (Karst.) Parke et Dodge, and also that verification for P. excentricum (Pauls.) Bal., P. claudicans (Pauls.) Bal., P. oblongum (Aur.) Parke et Dodge and Z. lanticalatum Loeb. Jr. et Loeb. III. P. conicides (Pauls.) Bal., P. antcuiciticum (Schimp.) Bal. P. pentagonum (Gran) Bal. and P. compressum (Abe) Bal. cysts were ' studied offering also an analysis for thecal sulcal plates for the latter species. Geographic distribution and temperature and salinity data for samples with living cysts are given

Enrique Eduardo Boschi

This year a pioneer of marine sciences in our country has passed away. With a prolific and extensive professional life, Enrique dedicated himself both to research and teaching, as well as to institutional strengthening and consolidation work that he was able to develop both in Argentina and internationally, mainly in Latin America. This brief review of his career and contributions to research, teaching and institutional consolidation precedes the next appearance of a publicaion dealing with these aspects in detail, together with the list of his publications and works as editor.Este año nos ha dejado un pionero de las ciencias marinas de nuestro país. Con una vida profesionalprolífica y amplia, Enrique se dedicó tanto a la investigación y la docencia, como a labores de construccióny consolidación institucional que supo desarrollar tanto en Argentina como en el ámbito internacional,principalmente Latinoamericano. Este breve reordatorio sobre su trayectoria y aportes en investigación, docencia y consolidación institucional precede a la próxima aparición de un trabajo en el que trataremos en detalle estos aspectos en conjunto con el listado de sus publicaciones y de las obras de las que fue editor

Occurrence of marine biotoxins and shellfish poisoning events and their causative organisms in argentine marine waters

In the Argentine Sea, marine phycotoxins of microalgal origin associatedwith five shellfish poisoning syndromes have been reported. The most problematic interms of toxicity and geographic distribution is paralytic shellfish poisoning (PSP), followedby diarrhetic shellfish poisoning (DSP). In contrast, amnesic shellfish poisoning(ASP), spiroimine shellfish poisoning (SSP), and azaspiracid shellfish poisoning (AZP)have not been reported to cause human illness or closures of shellfish harvest sites inArgentina to date but pose a potential risk, as associated toxins and producing organismsare present in Southwest Atlantic waters and were detected at subregulatory levelsin mollusks. Alexandrium catenella and Gymnodinium catenatum have been identifiedas producers of the PSP toxins C1/2, gonyautoxins (GTX1-4), saxitoxin (STX),and neosaxitoxin (NEO) in the Argentine Sea. Nine potentially toxigenic species ofthe diatom genus Pseudo-nitzschia have been reported for Argentinean coastal waters:P. australis, P. brasiliana, P. delicatissima, P. fraudulenta, P. multiseries, P. pseudodelicatissima,P. pungens, P. seriata, and P. turgidula, all of which are known to produce theneurotoxin domoic acid that causes ASP. Two genera have been identified as producersof DSP toxins in Argentina: the benthic dinoflagellate Prorocentrum lima and severalspecies of the pelagic dinoflagellate genus Dinophysis: D. acuminata, D. caudata,D. fortii, D. norvegica, and D. tripos. The occurrence of these species in Argentine watersis associated with okadaic acid (OA), dinophysistoxin-1 (DTX-1), pectenotoxin-2(PTX-2), and pectenotoxin-2 seco acid (PTX-2sa). Historically, yessotoxins (YTXs)were also included in DSP syndrome and all three known YTX-producers have beenconfirmed in Argentinean waters: Gonyaulax spinifera, Lingulodinium polyedra, andProtoceratium reticulatum, but of these only P. reticulatum could be associated with YTXproduction to date. Several species of the family Amphidomataceae, which cause AZP,have been reported for Argentina: Amphidoma languida, Azadinium dexteroporum,Az. luciferelloides, Az. poporum, and Az. spinosum. In Argentinean coastal waters, outof these species only Az. poporum has been identified as toxigenic to date, as it producesazaspiracid-2 (AZA-2) and its phosphorylated form. Currently in Argentina, seafood ismonitored for the risk of ASP, AZP, DSP, and PSP.Fil: Krock, Bernd. Alfred-Wegener-Institut. Helmholtz-Zentrum für Polar und Meeresforschung; AlemaniaFil: Ferrario, Martha Elba. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Ficología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Akselman Cardella, Rut. Instituto Nacional de Investigaciones y Desarrollo Pesquero; ArgentinaFil: Montoya, Nora Gladys. Instituto Nacional de Investigaciones y Desarrollo Pesquero; Argentin

Diversity of the diatom genus Fragilariopsis in the Argentine Sea and Antarctic waters: Morphology, distribution and abundance

Fragilariopsis species composition and abundance from the Argentine Sea and Antarctic waters were analyzed using light and electron microscopy. Twelve species (F. curta, F. cylindrus, F. kerguelensis, F. nana, F. obliquecostata, F. peragallii, F. pseudonana, F. rhombica, F. ritscheri, F. separanda, F. sublinearis and F. vanheurckii) are described and compared with samples from the Frenguelli Collection, Museo de La Plata, Argentina. F. peragallii was examined for the first time using electron microscopy, and F. pseudonana was recorded for the first time in Argentinean shelf waters. New information on the girdle view is included, except for the species F. curta, F. cylindrus and F. nana, for which information already existed. In the Argentine Sea, F. pseudonana was the most abundant Fragilariopsis species, and in Antarctic waters, F. curta was most abundant. Of the twelve species of Fragilariopsis documented, four occurred in the Argentine Sea, nine in the Drake Passage and twelve in the Weddell Sea. F. curta, F. kerguelensis, F. pseudonana and F. rhombica were present everywhere.Facultad de Ciencias Naturales y Muse

Diversity of the diatom genus Fragilariopsis in the Argentine Sea and Antarctic waters: Morphology, distribution and abundance

Fragilariopsis species composition and abundance from the Argentine Sea and Antarctic waters were analyzed using light and electron microscopy. Twelve species (F. curta, F. cylindrus, F. kerguelensis, F. nana, F. obliquecostata, F. peragallii, F. pseudonana, F. rhombica, F. ritscheri, F. separanda, F. sublinearis and F. vanheurckii) are described and compared with samples from the Frenguelli Collection, Museo de La Plata, Argentina. F. peragallii was examined for the first time using electron microscopy, and F. pseudonana was recorded for the first time in Argentinean shelf waters. New information on the girdle view is included, except for the species F. curta, F. cylindrus and F. nana, for which information already existed. In the Argentine Sea, F. pseudonana was the most abundant Fragilariopsis species, and in Antarctic waters, F. curta was most abundant. Of the twelve species of Fragilariopsis documented, four occurred in the Argentine Sea, nine in the Drake Passage and twelve in the Weddell Sea. F. curta, F. kerguelensis, F. pseudonana and F. rhombica were present everywhere.Facultad de Ciencias Naturales y Muse

Revisiting the 1991 algal bloom in shelf waters off Argentina: Azadinium luciferelloides sp. nov. (Amphidomataceae, Dinophyceae) identified as the causative species in a diverse community of other amphidomataceans

Amphidoma (Amphidomataceae) mostly attract attention because of their production potential of the lipophilic polyether phycotoxin azaspiracid (AZA). The genus Azadinium probably has a very wide geographical distribution. Blooms of Azadinium from the continental shelf off Argentina have been observed back in the early 1990, but were just recently published, and the causative species, identified at that time as Azadinium cf. spinosum, could not unequivocally be determined. Here we retrospectively analyzed old archived samples of one of the South Atlantic Azadinium bloom from 1991 with electron microscopy. It turned out that the dominant nanoplanktonic dinophycean species in fact represent a new species which we describe here based on the morphology. Azadinium luciferelloides sp. nov. is a small (approximately 9–14 μm cell length) thecate dinoflagellate with the dominant plate pattern of the genus (Po, X, 4´, 3a, 6´´ , 6C, 5S, 6´´´, 2´´´´), and with a small antapical spine. Azadinium luciferelloides differed from all other described species of Azadinium by the position of the ventral pore, which was located on the right ventral side in a notch of an otherwise symmetric pore plate. In addition, we recorded and documented the presence of other similar sized species of the Amphidomataceae in the samples. Our finding of Az. spinosum, Az. dalianense, Az. dexteroporum, and Amphidoma languida are the first record for the South Atlantic and thus describe an important range extension of these species. The diversity and importance of the Amphidomataceae for South Atlantic spring bloom plankton is now known and taxonomically documented, but cultures and/or analysis of AZA in field samples of the area are needed to clarify the AZA production potential of the local species and populations in order to finally evaluate the risk potential of AZA for AZA shellfish contamination in the Southwestern Atlantic region

Quistes planctonicos de dinoficeas en areas de plataforma del atlantico sudoccidental: I. Reporte taxonomico de la família Peridiniaceae ehrenberg Planktonic dinoflagelltes cysts in areas from the southwestern atlantic shelf: I. Taxonomic report on the Peridiniacace ehreber

This work constitutes a first contribution to the taxonomy of dinoflagellate resting cysts in planktonic samples of this region, being studied nine species of Protoperidinium Bergh and Zybabikodinium Loeblich Jr. et Loeblich III of the family Peridiniaceae. Incubation experiments with living material and parental thecae containing resting cysts in fixed samples allowed setting up of the cyst-theca relationship in P. obtusum (Karst.) Parke et Dodge, and also that verification for P. excentricum (Pauls.) Bal., P. claudicans (Pauls.) Bal., P. oblongum (Aur.) Parke et Dodge and Z. lanticalatum Loeb. Jr. et Loeb. III. P. conicides (Pauls.) Bal., P. antcuiciticum (Schimp.) Bal. P. pentagonum (Gran) Bal. and P. compressum (Abe) Bal. cysts were ' studied offering also an analysis for thecal sulcal plates for the latter species. Geographic distribution and temperature and salinity data for samples with living cysts are given

Estudios ecológicos en el Golfo San Jorge y adyacencias (Atlántico Sudoccidental) : Distribución, abundancia y variación estacional del fitoplancton en relación a factores Físico-químicos y la dinámica hidrológica

El estudio, basado en cuatro campañas estacionales durante 1984 y 1985, indicó la presencia -por advección de la masa de Agua Costera- de un frente termohalíno que presenta una rama hacia plataforma y otra costera. Entre primavera avanzada y otoño se desarrolla una termoclina, con reducidas concentraciones de nutrientes inorgánicos en la capa superior. Durante el invierno -con condiciones de homogeneidad vertical- existe elevada concentración de nutrientes. El desarrollo fitoplanctónico presenta una secuencia estacional típica de regiones templadas. En invierno las poblaciones fueron reducidas, con preponderancia de diatomeas. Durante el florecimiento primaveral se observaron los valores más elevados del ciclo asociados a Thalassiosira anguste-lineata, Alexandrium tamarense, Heterocapsa triquetra y Prorocentrum micans. En verano decreció abruptamente -predominando los dinoflagelados-, con un incremento menor en otoño debido a las diatomeas. En general, el desarrollo de diatomeas se vinculó al sistema frontal. La composición florística cuali-cuantitativa señala al golfo como área austral de transición con preponderancia de comunidades templado-frías. En primavera se presentó una rica flora de quistes de dinoflagelados, observándose enquistamiento. Se identificaron relaciones tróficas en el microplancton, observándose un acoplamiento espacial entre dinoflagelados predadores y dinoflagelados-presa fotosíntéticos. Se estímaron consumo e índices de pastoreo y selectividad de presas.This study was based on four seasonal cruises during 1984 and l985. It revealed a thermo-haline frontal system formed by the advection of the Coastal Water mass flowing in two branches, one ninning towards the coast and the other mid-shelf directed. The thermocline developed between late spring and autumn results in a low inorgarric nutrient concentration in the upper layer. Nonetheless in winter, a vertical homogeneity and high nutrient concentration were observed Phytoplankton development presented a typical temperate-seas armual cycle. ln winter, reduced populations were dominated by diatoms. The highest biomass concentration in the cycle coincided with the spring blooming, to which Thalassiosira anguste-lineata, Alexandrium tamarense, Heterocapsa triquetra and Prorocemrum micans were associated. Summer concentration decreased sharply with dinoflagellates being dominant, and a minor increase followed in auturnn owing to diatom populations. Usually, diatom growth was linked to the frontal region. The quali-quantitative flora composition denote this gulf as a southern transitional area with a dominance of temperate-cold communities. A high dinoflagellate cysts richeness and encystment were detected in spring. Trophic relations in the microplankton community were identified, and a spatial coupling of predator-dinoflagellates and photosynthetic prey-dinoflagellates was noted. Consumption and grazing and prey selectivity indexes were also estimated.Fil:Akselman, Rut. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Marine diatoms of Argentina: textile art-netting with science and art

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