Florecimientos algales nocivos producidos por Pyrodinium bahamense en Oaxaca, México (2009-2010) / Harmful algal blooms produced by Pyrodinium bahamense in Oaxaca, Mexico (2009-2010)

Objetivo. Monitorear el dinoflagelado Pyrodinium bahamense y sus toxinas en ostión de roca Striostrea prismatica en Santiago Astata y en Puerto Escondido, Oaxaca, de septiembre de 2009 a junio de 2010. Material y métodos. Se analizó mensualmente la abundancia de Pyrodinium bahamense mediante el método de Sedgewick-Rafter y la concentración de toxinas paralizantes y perfil tóxico en tejido blando del molusco en muestras compuestas de cada zona por el método de cromatografía líquida de alta resolución. Resultados. Se encontró alta abundancia de Pyrodinium bahamense en Santiago Astata en diciembre, febrero, abril y junio, y en Puerto Escondido en abril y junio. Los niveles de toxinas paralizantes fueron superiores al límite permisible para consumo humano en Santiago Astata en noviembre, diciembre, enero, febrero y junio; en la zona de Puerto Escondido, en diciembre y junio. Conclusiones. Estos niveles de toxinas representaron riesgo para la salud pública en la zona de estudio.

Objective. Pyrodinium bahamense monitoring in water and their toxins in rock oyster Striostrea prismatica in Santiago Astata and Puerto Escondido Oaxaca was performed from September 2009 to July 2010. Materials and methods. Pyrodinium bahamense abundance in water, and concentration and toxic profile of paralytic shellfish toxins were analyzed monthly in soft tissue of mollusk in composite samples in high performance liquid chromatography. Results. High abundance of Pyrodinium bahamense was found in Santiago Astata on December, February, April and June; and in Puerto Escondido on April and June. The concentrations of the paralyzing toxin that exceeded the regulatory limit for human consumption of mollusks (800 µg STX eq. kg-1) were presented in Santiago Astata on November, December, January, February and June; and in Puerto Escondido on December and June. Conclusions. For several months there was risk to public health due to the presence of paralytic shellfish toxins above the regulatory limit in oysters from the study area.

Population fluctuations of Pyrodinium bahamense and Ceratium furca (Dinophyceae) in Laguna Grande, Puerto Rico, and environmental variables associated during a three-year period / Fluctuaciones poblacionales de Pyrodinium bahamense y Ceratium furca (Dinophyceae) en Laguna Grande, Puerto Rico, y variables ambientales asociadas durante un periodo de tres años

Bioluminescent bays and lagoons are unique natural environments and popular tourist attractions. However, the bioluminescence in many of these water bodies has declined, principally due to anthropogenic activities. In the Caribbean, the bioluminescence in these bays and lagoons is mostly produced by the dinoflagellate Pyrodinium bahamense var. bahamense. Laguna Grande is one of the three year-round bioluminescent water bodies in Puerto Rico that are known to remain but P. bahamense var. bahamense density fluctuations have not been studied. In this study we describe water quality parameters and density fluctuations of the most common dinoflagellates in Laguna Grande, P. bahamense var. bahamense and Ceratium furca, over a three-year period. For this, three sampling stations were established in Laguna Grande from which water samples were collected in triplicate and analyzed for temperature, phosphates, nitrates, salinity, water transparency, fluorescence, and dinoflagellate densities, at the water surface and at 2m depth, from May 2003 to May 2006. The results showed a density fluctuation pattern for P. bahamense var. bahamense, where higher densities were observed mainly from April to September, and lower densities from October to February. Density fluctuations of C. furca were more erratic and a repetitive pattern was not observed. Densities of P. bahamense var. bahamense ranged from 0.48 to 90 978 cells/L and densities of C. furca ranged from 0 to 11 200 cells/L. The mean population density throughout the sampling period was significantly higher in P. bahamense var. bahamense (mean=18 958.5 cells/L) than in C. furca (mean=2 601.9 cells/L). Population densities of P. bahamense var. bahamense were negatively correlated with C. furca densities during the first year of sampling; however, they were positively correlated during the third year. Non-significant differences between surface and 2m depth samples were observed for temperature, phosphates, nitrates, salinity, fluorescence, and densities of P. bahamense var. bahamense and C. furca, suggesting a vertically mixed water column. Water transparency was positively correlated with salinity and negatively correlated with fluorescence. Fluorescence was negatively correlated with salinity. The mean population densities of P. bahamense var. bahamense and C. furca observed in this study were within the range of previous reports in other bioluminescent water bodies in Puerto Rico and Florida, USA. In order to conserve the continuous P. bahamense var. bahamense populations in Laguna Grande, as well as its bioluminescence, it is recommended to maintain the existing water flow levels in the 1.5km long inlet/outlet channel; to maintain unpolluted water quality parameters within the bay, the hydrographical basin and adjacent waters, and to preserve mangrove communities within the basin and adjacent areas. Results of this study may help to develop management plans aiming to conserve P. bahamense, its bioluminescence and the lagoon attraction.

Este estudio describe parámetros de calidad de agua y fluctuaciones en la densidad poblacional de Pyrodinium bahamense Plate 1906 y Ceratium furca (Ehrenberg) Claparède & Lachmann 1859, los dos dinoflagelados más abundantes en las bahías y lagunas bioluminiscentes de Puerto Rico, durante un periodo de tres años, en Laguna Grande, Puerto Rico. En P. bahamense se observó un patrón de densidad poblacional, donde se bservaron las densidades más altas mayormente desde abril hasta septiembre y las más bajas desde octubre hasta febrero. En C. furca las fluctuaciones en densidad fueron más erráticas y no se observó un patrón repetitivo. La densidad poblacional promedio de P. bahamense (media=18 958.5 células/L) fue significantemente mayor que la de C. furca (media=2 601.9 células/L). No se encontraron diferencias significantes entre las muestras de superficie y las de 2m de profundidad para temperatura, fosfatos, nitratos, salinidad, fluorescencia, y las densidades de P. bahamense y C. furca, lo que sugiere que la columna de agua está mezclada verticalmente. La densidad poblacional media de P. bahamense y C. furca en Laguna Grande está dentro del rango de las densidades que han sido reportadas para otras lagunas bioluminiscentes en Puerto Rico y Florida, EE.UU.

Bloom of Gymnodinium catenatum in Bahía Santiago and Bahía Manzanillo, Colima, Mexico

Gymnodinium bloom events are of concern, since they produce toxins, which have unfavorable consequences to marine ecosystems, human health and the economy. This report describes the physico-chemical conditions that were present during the algal bloom event on May 2010 in Bahía Manzanillo and Bahía Santiago, Colima, Mexico. For this, seawater nutrient analysis, phytoplankton counts, identification, and toxicity tests were undertaken. Nutrients in seawater were determined using colorimetric techniques, the higher concentrations (8.88μM DIN, 0.78μM PO4 and 24.34μM SiO2) were related with upwelling waters that promoted the algal bloom that began after registering the year lowest sea-surface temperature, favoring the rapid growth of G. catenatum (up to 1.02 x10(7)cells/L). Phytoplankton counting was carried out using sedimentation chambers and cells enumerated on appropriated area. The bloom persisted in the bays for approximately two weeks and was associated with toxicity (determined with HPLC) in local oysters (1525.8μg STXeq/100g), and in phytoplankton (10.9pg STXeq/cells) samples. Strong variations in cell toxicity (1.4 to 10.9pg STXeq/cells), most likely reflected the availability of inorganic nutrients. The toxin profile of the phytoplankton samples consisted of 11 toxins and resembled those recorded for several strains of G. catenatum isolated from other coastal areas of Mexico.

La proliferación de Gymnodinium son motivo de preocupación, debido a que en algunas circunstancias producen toxinas, que tienen consecuencias desfavorables para los ecosistemas marinos, la salud humana y la economía. Este trabajo describe las condiciones fisicoquímicas presentes durante una proliferación algal detectado en mayo de 2010 en la Bahía de Santiago y Bahía Manzanillo (Colima, México). La proliferación algal inició poco tiempo después de registrarse las temperaturas oceánicas superficiales más bajas del año, las cuales permitieron un aumento de las concentraciones de nutrientes (8.88μM DIN, 0.78μM PO4 and 24.34μM SiO2) que favorecieron el desarrollo de G. catenatum (hasta 1.02 x10(7)cel/L). Esta proliferación se detectó en las bahías durante dos semanas y fue relacionada con toxicidad en ostiones de la localidad (1525.8μg STXeq/100g) y en muestras de fitoplancton (10.9pg STXeq/cel). Fuertes variaciones en la toxicidad de G. catenatum (1.4 a 10.9pg STXeq/cel) pudieron reflejar la disponibilidad de nutrientes inorgánicos. El perfil de toxinas de las muestras del fitoplancton consistieron en 11 toxinas semejantes a las de varias cepas de G. catenatum aisladas de otras áreas de las costas de México.

Utilization of various nitrogen, phosphorus, and selenium compounds by Cochlodinium polykrikoides.

The abilityof Cochlodinium polykrikoides to use various nitrogen, phosphorus, and selenium compounds as a nutrient source was examined in batch culture experiments to obtain biological information on the mechanism of C. polykrikoides bloom formation. C. polykrikoides grew using a variety of organic or inorganic nitrogen sources except for L-proline. Maximum yields of C. polykrikoides were obtained by gradually increasing ammonium from 5 to 20 microM, but the yield was inhibited by addition of more than 50 microM. Growth was observed in media containing various phosphorus sources, such as phosphate and 11 different organic compounds. Organic nitrogen and phosphorus seem to play an important role in the dominance of phytoplankton species and mass growth of C. polykrikoides. The ability to use a variety of organic nutrients may allow C. polykrikoides to grow to a high density in spite of inorganic nitrogen and phosphorus depletion. C. polykrikoides grew in the presence of selenite, selenate, and Se-(methyl) selenocysteine hydrochloride. However, growth yield was inhibited by addition of more than 500 microM selenate and 1000 microM Se-(methyl) selenocysteine hydrochloride. Therefore, much of the oil effluents seen in 2005 may have a temporary inhibitory action on C. polykrikoides growth but can be expected to have a positive effect in the long term.

Growth, delayed fluorescence and pigment composition of four Prorocentrum minimum strains growing at two salinities

Prorocentrum minimum is a potentially harmful and widely distributed marine dinoflagellate. Several P. minimum strains have already been studied, showing phylogenetical relations of strains isolated from the same geographical regions. Similarity among the strains was further examined on the basis of their physiology. Pigment composition and concentration, as well as delayed fluorescence (DF) decay kinetics and intensity, were measured in four P. minimum strains isolated from the Baltic and Adriatic Seas. The strains were grown at two salinities characteristic of the Baltic (8 PSU) and North Adriatic Seas (32 PSU). Strain differences in DF decay kinetics and growth did not always follow their genetic relations. While two strains showed similarities to the previously described strains from the Baltic and Adriatic Seas in DF parameters, the other two strains seemed to be specific. The differences among strains isolated from the same sea could stem from adaptations to conditions in the specific habitats. Cluster analysis based on the ratio of individual carotenoid pigments concentrations to the chlorophyll a concentration or to total carotenoids were not conclusive in showing relations among the strains. Among the measured pigments, only peridinin concentration depended on salinity in all st.

Epiphytic dinoflagellates associated with ciguatera in the northwestern coast of Cuba

The spatial and temporal abundance of epiphytic dinoflagellates associated with ciguatera was studied over two annual cycles (March 1999 to March 2000 and March 2001 to March 2002) in the northwestern coast of Cuba. From 14 species of macroalgae (Phaeophyta, Chlorophyta, and Rhodophyta), 1340 samples were obtained identifying seven species as potentially noxious; five of them are new reports for Cuba's phytobenthos: Prorocentrum belizeanum Faust, P. concavum Fukuyo, P. mexicanum Tafall, Coolia monotis Meunier, and Ostreopsis lenticularis Fukuyo. ANOVA/MANOVA analysis showed significant spatial differences: lower cell abundance near the shoreline adjacent to a river inlet and higher cell abundance in the deepest area. Prorocentrum lima (Ehrenberg) Dodge 1975 was found mainly on Phaeophyta followed by Chlorophyta and Rhodophyta. Gambierdiscus toxicus was found mainly on Phaeophyta followed by Rhodophyta and Chlorophyta. All the species reported in the study area were mainly on Padina spp. (Phaeophyta). Acanthophora spicifera (Rhodophyta) did not host dinoflagellate species. Environmental conditions in summer (higher temperature, more nutrients, greater water transparency, and low wind intensity) are suitable for macroalgae development, which serves as a substrate for potentially harmful dinoflagellates, and possibly the main vector for spreading ciguatera along the coast of Cuba.

Se estudió la abundancia espacial y temporal de dinoflagelados epífitos asociados a la ciguatera durante dos ciclos anuales (marzo 1999 a marzo 2000, y marzo 2001 a marzo 2002) en la costa del noroeste de Cuba. Recolectamos 14 especies de macroalgas (Phaeophyta, Chlorophyta y Rhodophyta) y obtuvimos 1340 muestras. Identificamos siete especies de dinoflagelados potencialmente nocivas, cinco de ellas nuevos registros para el fitobentos cubano: Prorocentrum belizeanum Faust, P. concavum Fukuyo, P. mexicanum Tafall, Coolia monotis Meunier, y Ostreopsis lenticulares Fukuyo. El análisis de ANOVA/MANOVA mostró diferencias espaciales significativas: la abundancia celular más baja se encontró cerca de la desembocadura del río y la más alta en el área más profunda. Prorocentrum lima (Ehrenberg) Dodge, se encontró principalmente sobre las Phaeophyta seguido de las Chlorophyta y Rhodophyta. Gambierdiscus toxicus se encontró principalmente sobre las Phaeophyta seguido de las Rhodophyta y Chlorophyta. Todas las especies halladas en el área del estudio estaban sobre Padina spp. (Phaeophyta). No se encontró ninguna especie de dinoflagelado sobre Acanthophora spicifera (Rhodophyta). Las condiciones ambientales en verano (temperatura, nutrientes, transparencia de agua y la baja velocidad del viento) favorecen el desarrollo de las macroalgas, siendo un substrato adecuado para el desarrollo de dinoflagelados potencialmente nocivos, y posiblemente el vector principal para la extensión de la ciguatera en la costa noroeste cubana.

Presencia de Cochlodinium catenatum (Gymnodiniales: Gymnodiniaceae) en mareas rojas de Bahía de Banderas, Pacífico mexicano / Presence of Cochlodinium catenatum (Gymnodiniales: Gymnodiniaceae) in red tides of Bahia de Banderas, Mexican Pacific

Se describe la evolución de una proliferación algal ictiotóxica (julio a diciembre del 2000) causada por el dinoflagelado Cochlodinium catenatum. La multiplicación anormal de este dinoflagelado se presentó a manera de decoloraciones dispersas dentro de un intervalo de temperatura de 25-32 º C y salinidades de 33-35 ups. La densidad de C. catenatum fue desde no detectable hasta 10 841 éls ml-1 . El evento se presentó en grandes extensiones en la Bahía de Banderas, afectando a 13 especies de peces, cuya muerte masiva se debió a sofocación por la obstrucción en las agallas y por excesiva producción de mucus. La población humana aledaña no presentó afecciones respiratorias ni irritaciones en la piel. Las dimensiones de C. catenatum sugieren que pueda presentar una reproducción hologámica y heterotálica. Por sus características morfológicas se sugiere que C. polykrikoides, C. heterolobatum y C. catenatum son una única especie. Esta última parece de reciente introducción en el Pacífico mexicano

The evolution of an ichthiotoxic algal bloom caused by the dinoflagellate Cochlodinium catenatum was studied from July to December 2000. The abnormal multiplication of this dinoflagellate occurred in the form of a discoloration spreading between a temperature and salinity interval of 25-32°C and 33-35 ups, respectively. The density of C. catenatum reached 10 841 cells ml-1 . The event was observed in large areas of Banderas Bay affecting 13 fish species, whose massive killing was due to suffocation (gill obstruction and excessive mucus production). The human population around the area did not present respiratory affections or skin irritation. The C. catenatum measurements suggest a hologamic and heterothalic reproduction. Their morphological characteristics suggest that C. polykrikoides, C. heterolobatum and C. catenatum are the same species. It is estimated that the species could be a recent introduction in the Mexican Pacific

Blooms of Cochlodinium polykrikoides (Gymnodiniaceae) in the Gulf of California, Mexico

Cochlodinium polykrikoides was the species responsible for the discoloration that occurred between September 15th and 27th , 2000 in a shallow coastal lagoon located in the southern part of the Bahía de La Paz, on the west side of the Gulf of California. Blooms of C. polykrikoides were observed four days after two rainy days with a seawater temperature of 29 to 31°C. Nutrient concentration ranges during the bloom were 0.165- 0.897 µM NO2 +NO3 , 0.16-3.25 µM PO4 , and 1.0-35.36 µM SiO4 . Abundance of C. polykrikoides ranged from 360 x 103 to 7.05 x 106 /cells l-1 . Biomass expressed in terms of chlorophyll a was high, ranging from 2.7 to 56.8 mg/m3 . A typical dinoflagellate pigment profile (chlorophyll a and c, peridinin, diadinoxantin, and b -carotene) was recorded. In this study, the red tide occurred in front of several fish and shrimp-culture ponds. No PST toxins were found in the samples. However, 180 fish were found dead in the infected fish-pond; the gills were the most affected part. C. polykrikoides is a cyst-forming species that recurs in this area. New blooms were observed in November 2000 and September-November 2001 in the same area. Anthropogenic activities, such as eutrophication caused by water discharge in this shallow lagoon, and nutrient enrichment in the culture ponds, as well as effects from precipitation and wind stress, could have favored the outbreak of this dinoflagellate

Durante el desarrollo de una marea roja ocurrida del 15 al 27 de septiembre del año 2000 en la Ensenada de La Paz, B.C.S. se tomaron muestras de agua con una botella Van Dorn para determinar la temperatura, la especie causante y la cantidad de nutrientes y pigmentos fotosintéticos. Se hicieron análisis de toxinas de Cochlodinium polykrikoides, la especie responsable de esta marea roja. La mayoría de los especimenes formaron cadenas de cuatro células y raramente de dos. La abundancia fue de 360 x 103 a 7.05 x 106 /cels l-1 . Los florecimientos de C. polykrikoides ocurrieron cuatro días después de dos días lluviosos; el intervalo de temperatura fue de 29 a 31°C. La concentración de nutrientes registrada durante este fenómeno fue 0.165-0.897 µM NO2 +NO3 , 0.16-3.25 µM PO4 , y 1.0-35.36 µM SiO4 . El perfil pigmentario reveló la presencia de clorofila a y c, peridinina, diadinoxantina, y b -caroteno. La biomasa total expresada en clorofila a fue alta, oscilando entre 2.7 y 56.8 mg/m3 , mientras que la biomasa de Cochlodinium, expresada en peridinina, varió entre 0.68 y 32.03 mg/m3 . En este estudio, la marea roja se desarrolló cerca de varios estanques de cultivo de peces y camarón. En uno de ellos proliferó C. polykrikoides. Los análisis de toxinas PST fueron negativos; sin embargo, durante el incremento de las proliferaciones algunos estanques fueron alcanzados y murieron 180 peces, principalmente pargos (Lutjanus argentiventis, Pomadasys macracantus). Las branquias fueron las partes más afectadas. En condiciones desfavorables C. polykrikoides forma quistes, lo cual ha provocado su recurrente proliferación en el área, registrándose nuevas proliferaciones en noviembre del 2000 y en septiembre-noviembre del 2001. Actividades antropogénicas como la eutroficación causada por la descarga de aguas residuales y de nutrientes de los estanques de cultivo, pudieran estar favoreciendo la proliferación de este dinoflagelado

Paralytic Shellfish Poisoning (PSP) in Margarita Island, Venezuela

A severe outbreak of Paralytic Shellfish Poisoning (PSP) occurred in Manzanillo and Guayacán, northwestern coast of Margarita Island, Venezuela, between August and October 1991. A bloom of dinoflagellates including Prorocentrum gracile, Gymnodinium catenatum and Alexandrium tamarense seemed to be responsible for this outbreak. Levels of PSP toxins in mussels (Perna perna) exceeded the international safety limit of saxitoxin, 80 µg STX/100 g meat. PSP toxin values varied between 2 548 and 115 µg STX/100 g meat in Manzanillo, and between 1 422 and 86 µg STX/100 g meat in Guayacán. At both locations, the highest levels were detected in August, when 24 patients exhibited typical symptoms of PSP toxicity after consuming cooked mussels (16 required hospitalization). A high pressure liquid chromatographic (HPLC) procedure was recently used on the 1991 samples. The major toxin detected in samples of both locations was decarbamoyl saxitoxin (dcSTX), but low concentrations of saxitoxin were also found in Manzanillo samples. Gonyautoxins GTX1, GTX2 and GTX3 were detected only at Guayacán, while in both locations, decarbamoylgonyatouxin (dcGTX2,3) toxins were detected. These findings represent the first time that causative toxins of PSP in Venezuela have been chemically identified, and confirm the presence of dcSTX and dcGTX in mussels from the Caribbean Sea. The presence of dcSTX and dcGTX in shellfish is indicative that Gymnodinium catenatum was a causative organism for outbreak of PSP

Un severo brote de intoxicación paralizante por moluscos (PSP en inglés) ocurrió en Manzanillo y Guayacán en la costa noroeste de la Isla de Margarita, Venezuela entre agosto y octubre de 1991. Una proliferación de Prorocentrum gracile, Gymnodinium catenatum y Alexandrium tamarense causó el brote. Los niveles de PSP en mejillón (Perna perna) superaron los niveles máximos permisibles de saxitoxina, 80 µg STX/100g carne. Los niveles de toxinas variaron entre 2 548 y 115 µg STX/100 g carne en Manzanillo y entre 1 422 y 86 µg STX/100g carne en Guayacán. En ambas localidades, los máximos niveles se detectaron en agosto, cuando 24 personas presentaron síntomas típicos de PSP después de consumir mejillones cocidos (16 fueron hospitalizados). Se aplicó recientemente cromatografía líquida de alta presión (HPLC) a muestras del año 1991 y la toxina más detectada fue decarbamoyl saxitoxina (dcSTX), pero también se encontró saxitoxinas en muestras de Manzanillo. Las gonyautoxinas GTX1, GTX2 y GTX3 solo se encontraron en Guayacán; en ambas localidades se detectó decarbamoylgonyatouxin (dcGTX2,3). Estos hallazgos representan la primera vez que las toxinas causantes de un brote de PSP en Venezuela han sido químicamente identificadas, confirmando la presencia de dcSTX y dcGTX en mejillones del mar Caribe. La presencia de dcSTX y dcGTX en moluscos, indica que G. catenatum fue el organismo responsable de la intoxicación

Dinámica espacio-temporal de organismos precursores de marea roja en la costa Pacífica de América del Norte y Centroamérica / Spatial-temporal dynamics of red tide precursor organisms at the Pacific coast of North and Central America

La región costera del Pacífico de Centro y Norte America ha sido afectada de manera frecuente por fenómenos que se denominan proliferaciones algales nocivas o en inglés, "Harmful Algal Blooms" (HAB). A pesar de la gran cantidad de efectos en la salud pública, las actividades económicas y el medio ambiente, aún existe una abrumadora carencia de información en el tema. Esto no permite establecer si las causas principales de este evidente aumento en el número e intensidad de los eventos son naturales o antropogénicas. La incrementada utilización de las zonas costeras para actividades humanas encuentra paralelo en el denominado cambio climático, lo que dificulta discriminar entre la posible influencia de estos dos fenómenos. Series de datos de larga duración en regiones reducidas, así como las observaciones esporádicas realizadas cuando se presenta algún evento, nos permite comparar regímenes climáticos, condiciones geográficas, disponibilidad de nutrientes (incluyendo la eutroficación) y parámetros oceanográficos que promueven o permiten el desarrollo y mantenimiento de las proliferaciones, haciendo evidentes cambios drásticos en la biodiversidad y la biogeografía de los organismos productores de HAB

The Pacific coast of Central and North America has long been and still is impacted by the flourishing of microalgal populations known as Harmful Algal Blooms (HABs). The organisms that have caused recent HABs episodes in the region are among others, Gymnodinium catenatum, Pyrodinium bahamense var. compressum, and recently Cochlodinium cf. catenatum. In spite of the accumulated effects on the human health, the economic activities and the environment, scarce information is available on the subject. The augmented use of coastal zones for human activities is also paralleled by increased awareness of global climate changes. Thus, it is not an easy task to discriminate anthropogenic or natural phenomena, or both, as the major driving forces. The long-term data sets available for limited regions, as well as some sporadic observations during notorious blooms, allowed us to discriminate major changes in the biodiversity and biogeography of HAB organisms. Main changes refer to number of events, covered area, duration and frequency, number of blooming species and appearance of not previously reported harmful taxa. The variables more clearly related to these dynamic phenomena, seems to be sea surface temperature and wind force, but it is not yet possible to weight their contributions. The participation of rain is not fully evaluated to date. The collaborative communication among small-budget monitoring operations in the region allowed to "pass the voice" about peaking concentrations of HAB organisms, diminishing the risk of poisoning

Effects of basic oxygen furnace slag and inorganic nutrients on the germination of resting cysts of two toxic dinoflagellates.

Effects of basic oxygen furnace (BOF) slag, inorganic nutrients and H2S on the germination of resting cysts of two toxic dinoflagellates Alexandrium catenella/tamarense and Gymnodinium catenatum were studied in batch cultures. The germination rate of the test species has increased by 23-25%, when the concentration of NO3--N or H2S in culture medium has increased to 2.0 ppm. At the treatment of enriched NH4+-N and PO43--p, the germination of resting cyst was increased. Nevertheless, the increased range in germination rates was less than those of NO3--N and H2S. When BOF slag in culture medium increased to 50 mg/ml (or 500 g/m2), the cyst germination rate fell to less than 5%. At higher level of concentrations germination was completely inhibited. Adding BOF slag to the culture medium reduced the concentration of inorganic salts and H2S in seawater and sediments, resulting in the inhibition of cyst germination. These findings demonstrate the potential use of BOF slag on the sediments seed bank of red tide organism because it has an ability to inhibit resting cysts germination.